diffs: replace compare controller with new html based diffs:

* side/side + unified support
* redesign of diff changes/operations
* added button to see file before the change
* auto collapses large diffs

refs  #4232

licenses/diff_match_patch_license.txt

@@ -0,0 +1,14 b''
+Copyright 2006 Google Inc.
+http://code.google.com/p/google-diff-match-patch/
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+  http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.

rhodecode/lib/diff_match_patch.py

@@ -0,0 +1,1919 b''
+#!/usr/bin/python2.4
+
+from __future__ import division
+
+"""Diff Match and Patch
+
+Copyright 2006 Google Inc.
+http://code.google.com/p/google-diff-match-patch/
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+  http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+"""
+
+"""Functions for diff, match and patch.
+
+Computes the difference between two texts to create a patch.
+Applies the patch onto another text, allowing for errors.
+"""
+
+__author__ = '[e-mail] (Neil Fraser)'
+
+import math
+import re
+import sys
+import time
+import urllib
+
+class diff_match_patch:
+  """Class containing the diff, match and patch methods.
+
+  Also contains the behaviour settings.
+  """
+
+  def __init__(self):
+    """Inits a diff_match_patch object with default settings.
+    Redefine these in your program to override the defaults.
+    """
+
+    # Number of seconds to map a diff before giving up (0 for infinity).
+    self.Diff_Timeout = 1.0
+    # Cost of an empty edit operation in terms of edit characters.
+    self.Diff_EditCost = 4
+    # At what point is no match declared (0.0 = perfection, 1.0 = very loose).
+    self.Match_Threshold = 0.5
+    # How far to search for a match (0 = exact location, 1000+ = broad match).
+    # A match this many characters away from the expected location will add
+    # 1.0 to the score (0.0 is a perfect match).
+    self.Match_Distance = 1000
+    # When deleting a large block of text (over ~64 characters), how close do
+    # the contents have to be to match the expected contents. (0.0 = perfection,
+    # 1.0 = very loose).  Note that Match_Threshold controls how closely the
+    # end points of a delete need to match.
+    self.Patch_DeleteThreshold = 0.5
+    # Chunk size for context length.
+    self.Patch_Margin = 4
+
+    # The number of bits in an int.
+    # Python has no maximum, thus to disable patch splitting set to 0.
+    # However to avoid long patches in certain pathological cases, use 32.
+    # Multiple short patches (using native ints) are much faster than long ones.
+    self.Match_MaxBits = 32
+
+  #  DIFF FUNCTIONS
+
+  # The data structure representing a diff is an array of tuples:
+  # [(DIFF_DELETE, "Hello"), (DIFF_INSERT, "Goodbye"), (DIFF_EQUAL, " world.")]
+  # which means: delete "Hello", add "Goodbye" and keep " world."
+  DIFF_DELETE = -1
+  DIFF_INSERT = 1
+  DIFF_EQUAL = 0
+
+  def diff_main(self, text1, text2, checklines=True, deadline=None):
+    """Find the differences between two texts.  Simplifies the problem by
+      stripping any common prefix or suffix off the texts before diffing.
+
+    Args:
+      text1: Old string to be diffed.
+      text2: New string to be diffed.
+      checklines: Optional speedup flag.  If present and false, then don't run
+        a line-level diff first to identify the changed areas.
+        Defaults to true, which does a faster, slightly less optimal diff.
+      deadline: Optional time when the diff should be complete by.  Used
+        internally for recursive calls.  Users should set DiffTimeout instead.
+
+    Returns:
+      Array of changes.
+    """
+    # Set a deadline by which time the diff must be complete.
+    if deadline == None:
+      # Unlike in most languages, Python counts time in seconds.
+      if self.Diff_Timeout <= 0:
+        deadline = sys.maxint
+      else:
+        deadline = time.time() + self.Diff_Timeout
+
+    # Check for null inputs.
+    if text1 == None or text2 == None:
+      raise ValueError("Null inputs. (diff_main)")
+
+    # Check for equality (speedup).
+    if text1 == text2:
+      if text1:
+        return [(self.DIFF_EQUAL, text1)]
+      return []
+
+    # Trim off common prefix (speedup).
+    commonlength = self.diff_commonPrefix(text1, text2)
+    commonprefix = text1[:commonlength]
+    text1 = text1[commonlength:]
+    text2 = text2[commonlength:]
+
+    # Trim off common suffix (speedup).
+    commonlength = self.diff_commonSuffix(text1, text2)
+    if commonlength == 0:
+      commonsuffix = ''
+    else:
+      commonsuffix = text1[-commonlength:]
+      text1 = text1[:-commonlength]
+      text2 = text2[:-commonlength]
+
+    # Compute the diff on the middle block.
+    diffs = self.diff_compute(text1, text2, checklines, deadline)
+
+    # Restore the prefix and suffix.
+    if commonprefix:
+      diffs[:0] = [(self.DIFF_EQUAL, commonprefix)]
+    if commonsuffix:
+      diffs.append((self.DIFF_EQUAL, commonsuffix))
+    self.diff_cleanupMerge(diffs)
+    return diffs
+
+  def diff_compute(self, text1, text2, checklines, deadline):
+    """Find the differences between two texts.  Assumes that the texts do not
+      have any common prefix or suffix.
+
+    Args:
+      text1: Old string to be diffed.
+      text2: New string to be diffed.
+      checklines: Speedup flag.  If false, then don't run a line-level diff
+        first to identify the changed areas.
+        If true, then run a faster, slightly less optimal diff.
+      deadline: Time when the diff should be complete by.
+
+    Returns:
+      Array of changes.
+    """
+    if not text1:
+      # Just add some text (speedup).
+      return [(self.DIFF_INSERT, text2)]
+
+    if not text2:
+      # Just delete some text (speedup).
+      return [(self.DIFF_DELETE, text1)]
+
+    if len(text1) > len(text2):
+      (longtext, shorttext) = (text1, text2)
+    else:
+      (shorttext, longtext) = (text1, text2)
+    i = longtext.find(shorttext)
+    if i != -1:
+      # Shorter text is inside the longer text (speedup).
+      diffs = [(self.DIFF_INSERT, longtext[:i]), (self.DIFF_EQUAL, shorttext),
+               (self.DIFF_INSERT, longtext[i + len(shorttext):])]
+      # Swap insertions for deletions if diff is reversed.
+      if len(text1) > len(text2):
+        diffs[0] = (self.DIFF_DELETE, diffs[0][1])
+        diffs[2] = (self.DIFF_DELETE, diffs[2][1])
+      return diffs
+
+    if len(shorttext) == 1:
+      # Single character string.
+      # After the previous speedup, the character can't be an equality.
+      return [(self.DIFF_DELETE, text1), (self.DIFF_INSERT, text2)]
+
+    # Check to see if the problem can be split in two.
+    hm = self.diff_halfMatch(text1, text2)
+    if hm:
+      # A half-match was found, sort out the return data.
+      (text1_a, text1_b, text2_a, text2_b, mid_common) = hm
+      # Send both pairs off for separate processing.
+      diffs_a = self.diff_main(text1_a, text2_a, checklines, deadline)
+      diffs_b = self.diff_main(text1_b, text2_b, checklines, deadline)
+      # Merge the results.
+      return diffs_a + [(self.DIFF_EQUAL, mid_common)] + diffs_b
+
+    if checklines and len(text1) > 100 and len(text2) > 100:
+      return self.diff_lineMode(text1, text2, deadline)
+
+    return self.diff_bisect(text1, text2, deadline)
+
+  def diff_lineMode(self, text1, text2, deadline):
+    """Do a quick line-level diff on both strings, then rediff the parts for
+      greater accuracy.
+      This speedup can produce non-minimal diffs.
+
+    Args:
+      text1: Old string to be diffed.
+      text2: New string to be diffed.
+      deadline: Time when the diff should be complete by.
+
+    Returns:
+      Array of changes.
+    """
+
+    # Scan the text on a line-by-line basis first.
+    (text1, text2, linearray) = self.diff_linesToChars(text1, text2)
+
+    diffs = self.diff_main(text1, text2, False, deadline)
+
+    # Convert the diff back to original text.
+    self.diff_charsToLines(diffs, linearray)
+    # Eliminate freak matches (e.g. blank lines)
+    self.diff_cleanupSemantic(diffs)
+
+    # Rediff any replacement blocks, this time character-by-character.
+    # Add a dummy entry at the end.
+    diffs.append((self.DIFF_EQUAL, ''))
+    pointer = 0
+    count_delete = 0
+    count_insert = 0
+    text_delete = ''
+    text_insert = ''
+    while pointer < len(diffs):
+      if diffs[pointer][0] == self.DIFF_INSERT:
+        count_insert += 1
+        text_insert += diffs[pointer][1]
+      elif diffs[pointer][0] == self.DIFF_DELETE:
+        count_delete += 1
+        text_delete += diffs[pointer][1]
+      elif diffs[pointer][0] == self.DIFF_EQUAL:
+        # Upon reaching an equality, check for prior redundancies.
+        if count_delete >= 1 and count_insert >= 1:
+          # Delete the offending records and add the merged ones.
+          a = self.diff_main(text_delete, text_insert, False, deadline)
+          diffs[pointer - count_delete - count_insert : pointer] = a
+          pointer = pointer - count_delete - count_insert + len(a)
+        count_insert = 0
+        count_delete = 0
+        text_delete = ''
+        text_insert = ''
+
+      pointer += 1
+
+    diffs.pop()  # Remove the dummy entry at the end.
+
+    return diffs
+
+  def diff_bisect(self, text1, text2, deadline):
+    """Find the 'middle snake' of a diff, split the problem in two
+      and return the recursively constructed diff.
+      See Myers 1986 paper: An O(ND) Difference Algorithm and Its Variations.
+
+    Args:
+      text1: Old string to be diffed.
+      text2: New string to be diffed.
+      deadline: Time at which to bail if not yet complete.
+
+    Returns:
+      Array of diff tuples.
+    """
+
+    # Cache the text lengths to prevent multiple calls.
+    text1_length = len(text1)
+    text2_length = len(text2)
+    max_d = (text1_length + text2_length + 1) // 2
+    v_offset = max_d
+    v_length = 2 * max_d
+    v1 = [-1] * v_length
+    v1[v_offset + 1] = 0
+    v2 = v1[:]
+    delta = text1_length - text2_length
+    # If the total number of characters is odd, then the front path will
+    # collide with the reverse path.
+    front = (delta % 2 != 0)
+    # Offsets for start and end of k loop.
+    # Prevents mapping of space beyond the grid.
+    k1start = 0
+    k1end = 0
+    k2start = 0
+    k2end = 0
+    for d in xrange(max_d):
+      # Bail out if deadline is reached.
+      if time.time() > deadline:
+        break
+
+      # Walk the front path one step.
+      for k1 in xrange(-d + k1start, d + 1 - k1end, 2):
+        k1_offset = v_offset + k1
+        if k1 == -d or (k1 != d and
+            v1[k1_offset - 1] < v1[k1_offset + 1]):
+          x1 = v1[k1_offset + 1]
+        else:
+          x1 = v1[k1_offset - 1] + 1
+        y1 = x1 - k1
+        while (x1 < text1_length and y1 < text2_length and
+               text1[x1] == text2[y1]):
+          x1 += 1
+          y1 += 1
+        v1[k1_offset] = x1
+        if x1 > text1_length:
+          # Ran off the right of the graph.
+          k1end += 2
+        elif y1 > text2_length:
+          # Ran off the bottom of the graph.
+          k1start += 2
+        elif front:
+          k2_offset = v_offset + delta - k1
+          if k2_offset >= 0 and k2_offset < v_length and v2[k2_offset] != -1:
+            # Mirror x2 onto top-left coordinate system.
+            x2 = text1_length - v2[k2_offset]
+            if x1 >= x2:
+              # Overlap detected.
+              return self.diff_bisectSplit(text1, text2, x1, y1, deadline)
+
+      # Walk the reverse path one step.
+      for k2 in xrange(-d + k2start, d + 1 - k2end, 2):
+        k2_offset = v_offset + k2
+        if k2 == -d or (k2 != d and
+            v2[k2_offset - 1] < v2[k2_offset + 1]):
+          x2 = v2[k2_offset + 1]
+        else:
+          x2 = v2[k2_offset - 1] + 1
+        y2 = x2 - k2
+        while (x2 < text1_length and y2 < text2_length and
+               text1[-x2 - 1] == text2[-y2 - 1]):
+          x2 += 1
+          y2 += 1
+        v2[k2_offset] = x2
+        if x2 > text1_length:
+          # Ran off the left of the graph.
+          k2end += 2
+        elif y2 > text2_length:
+          # Ran off the top of the graph.
+          k2start += 2
+        elif not front:
+          k1_offset = v_offset + delta - k2
+          if k1_offset >= 0 and k1_offset < v_length and v1[k1_offset] != -1:
+            x1 = v1[k1_offset]
+            y1 = v_offset + x1 - k1_offset
+            # Mirror x2 onto top-left coordinate system.
+            x2 = text1_length - x2
+            if x1 >= x2:
+              # Overlap detected.
+              return self.diff_bisectSplit(text1, text2, x1, y1, deadline)
+
+    # Diff took too long and hit the deadline or
+    # number of diffs equals number of characters, no commonality at all.
+    return [(self.DIFF_DELETE, text1), (self.DIFF_INSERT, text2)]
+
+  def diff_bisectSplit(self, text1, text2, x, y, deadline):
+    """Given the location of the 'middle snake', split the diff in two parts
+    and recurse.
+
+    Args:
+      text1: Old string to be diffed.
+      text2: New string to be diffed.
+      x: Index of split point in text1.
+      y: Index of split point in text2.
+      deadline: Time at which to bail if not yet complete.
+
+    Returns:
+      Array of diff tuples.
+    """
+    text1a = text1[:x]
+    text2a = text2[:y]
+    text1b = text1[x:]
+    text2b = text2[y:]
+
+    # Compute both diffs serially.
+    diffs = self.diff_main(text1a, text2a, False, deadline)
+    diffsb = self.diff_main(text1b, text2b, False, deadline)
+
+    return diffs + diffsb
+
+  def diff_linesToChars(self, text1, text2):
+    """Split two texts into an array of strings.  Reduce the texts to a string
+    of hashes where each Unicode character represents one line.
+
+    Args:
+      text1: First string.
+      text2: Second string.
+
+    Returns:
+      Three element tuple, containing the encoded text1, the encoded text2 and
+      the array of unique strings.  The zeroth element of the array of unique
+      strings is intentionally blank.
+    """
+    lineArray = []  # e.g. lineArray[4] == "Hello\n"
+    lineHash = {}   # e.g. lineHash["Hello\n"] == 4
+
+    # "\x00" is a valid character, but various debuggers don't like it.
+    # So we'll insert a junk entry to avoid generating a null character.
+    lineArray.append('')
+
+    def diff_linesToCharsMunge(text):
+      """Split a text into an array of strings.  Reduce the texts to a string
+      of hashes where each Unicode character represents one line.
+      Modifies linearray and linehash through being a closure.
+
+      Args:
+        text: String to encode.
+
+      Returns:
+        Encoded string.
+      """
+      chars = []
+      # Walk the text, pulling out a substring for each line.
+      # text.split('\n') would would temporarily double our memory footprint.
+      # Modifying text would create many large strings to garbage collect.
+      lineStart = 0
+      lineEnd = -1
+      while lineEnd < len(text) - 1:
+        lineEnd = text.find('\n', lineStart)
+        if lineEnd == -1:
+          lineEnd = len(text) - 1
+        line = text[lineStart:lineEnd + 1]
+        lineStart = lineEnd + 1
+
+        if line in lineHash:
+          chars.append(unichr(lineHash[line]))
+        else:
+          lineArray.append(line)
+          lineHash[line] = len(lineArray) - 1
+          chars.append(unichr(len(lineArray) - 1))
+      return "".join(chars)
+
+    chars1 = diff_linesToCharsMunge(text1)
+    chars2 = diff_linesToCharsMunge(text2)
+    return (chars1, chars2, lineArray)
+
+  def diff_charsToLines(self, diffs, lineArray):
+    """Rehydrate the text in a diff from a string of line hashes to real lines
+    of text.
+
+    Args:
+      diffs: Array of diff tuples.
+      lineArray: Array of unique strings.
+    """
+    for x in xrange(len(diffs)):
+      text = []
+      for char in diffs[x][1]:
+        text.append(lineArray[ord(char)])
+      diffs[x] = (diffs[x][0], "".join(text))
+
+  def diff_commonPrefix(self, text1, text2):
+    """Determine the common prefix of two strings.
+
+    Args:
+      text1: First string.
+      text2: Second string.
+
+    Returns:
+      The number of characters common to the start of each string.
+    """
+    # Quick check for common null cases.
+    if not text1 or not text2 or text1[0] != text2[0]:
+      return 0
+    # Binary search.
+    # Performance analysis: http://neil.fraser.name/news/2007/10/09/
+    pointermin = 0
+    pointermax = min(len(text1), len(text2))
+    pointermid = pointermax
+    pointerstart = 0
+    while pointermin < pointermid:
+      if text1[pointerstart:pointermid] == text2[pointerstart:pointermid]:
+        pointermin = pointermid
+        pointerstart = pointermin
+      else:
+        pointermax = pointermid
+      pointermid = (pointermax - pointermin) // 2 + pointermin
+    return pointermid
+
+  def diff_commonSuffix(self, text1, text2):
+    """Determine the common suffix of two strings.
+
+    Args:
+      text1: First string.
+      text2: Second string.
+
+    Returns:
+      The number of characters common to the end of each string.
+    """
+    # Quick check for common null cases.
+    if not text1 or not text2 or text1[-1] != text2[-1]:
+      return 0
+    # Binary search.
+    # Performance analysis: http://neil.fraser.name/news/2007/10/09/
+    pointermin = 0
+    pointermax = min(len(text1), len(text2))
+    pointermid = pointermax
+    pointerend = 0
+    while pointermin < pointermid:
+      if (text1[-pointermid:len(text1) - pointerend] ==
+          text2[-pointermid:len(text2) - pointerend]):
+        pointermin = pointermid
+        pointerend = pointermin
+      else:
+        pointermax = pointermid
+      pointermid = (pointermax - pointermin) // 2 + pointermin
+    return pointermid
+
+  def diff_commonOverlap(self, text1, text2):
+    """Determine if the suffix of one string is the prefix of another.
+
+    Args:
+      text1 First string.
+      text2 Second string.
+
+    Returns:
+      The number of characters common to the end of the first
+      string and the start of the second string.
+    """
+    # Cache the text lengths to prevent multiple calls.
+    text1_length = len(text1)
+    text2_length = len(text2)
+    # Eliminate the null case.
+    if text1_length == 0 or text2_length == 0:
+      return 0
+    # Truncate the longer string.
+    if text1_length > text2_length:
+      text1 = text1[-text2_length:]
+    elif text1_length < text2_length:
+      text2 = text2[:text1_length]
+    text_length = min(text1_length, text2_length)
+    # Quick check for the worst case.
+    if text1 == text2:
+      return text_length
+
+    # Start by looking for a single character match
+    # and increase length until no match is found.
+    # Performance analysis: http://neil.fraser.name/news/2010/11/04/
+    best = 0
+    length = 1
+    while True:
+      pattern = text1[-length:]
+      found = text2.find(pattern)
+      if found == -1:
+        return best
+      length += found
+      if found == 0 or text1[-length:] == text2[:length]:
+        best = length
+        length += 1
+
+  def diff_halfMatch(self, text1, text2):
+    """Do the two texts share a substring which is at least half the length of
+    the longer text?
+    This speedup can produce non-minimal diffs.
+
+    Args:
+      text1: First string.
+      text2: Second string.
+
+    Returns:
+      Five element Array, containing the prefix of text1, the suffix of text1,
+      the prefix of text2, the suffix of text2 and the common middle.  Or None
+      if there was no match.
+    """
+    if self.Diff_Timeout <= 0:
+      # Don't risk returning a non-optimal diff if we have unlimited time.
+      return None
+    if len(text1) > len(text2):
+      (longtext, shorttext) = (text1, text2)
+    else:
+      (shorttext, longtext) = (text1, text2)
+    if len(longtext) < 4 or len(shorttext) * 2 < len(longtext):
+      return None  # Pointless.
+
+    def diff_halfMatchI(longtext, shorttext, i):
+      """Does a substring of shorttext exist within longtext such that the
+      substring is at least half the length of longtext?
+      Closure, but does not reference any external variables.
+
+      Args:
+        longtext: Longer string.
+        shorttext: Shorter string.
+        i: Start index of quarter length substring within longtext.
+
+      Returns:
+        Five element Array, containing the prefix of longtext, the suffix of
+        longtext, the prefix of shorttext, the suffix of shorttext and the
+        common middle.  Or None if there was no match.
+      """
+      seed = longtext[i:i + len(longtext) // 4]
+      best_common = ''
+      j = shorttext.find(seed)
+      while j != -1:
+        prefixLength = self.diff_commonPrefix(longtext[i:], shorttext[j:])
+        suffixLength = self.diff_commonSuffix(longtext[:i], shorttext[:j])
+        if len(best_common) < suffixLength + prefixLength:
+          best_common = (shorttext[j - suffixLength:j] +
+              shorttext[j:j + prefixLength])
+          best_longtext_a = longtext[:i - suffixLength]
+          best_longtext_b = longtext[i + prefixLength:]
+          best_shorttext_a = shorttext[:j - suffixLength]
+          best_shorttext_b = shorttext[j + prefixLength:]
+        j = shorttext.find(seed, j + 1)
+
+      if len(best_common) * 2 >= len(longtext):
+        return (best_longtext_a, best_longtext_b,
+                best_shorttext_a, best_shorttext_b, best_common)
+      else:
+        return None
+
+    # First check if the second quarter is the seed for a half-match.
+    hm1 = diff_halfMatchI(longtext, shorttext, (len(longtext) + 3) // 4)
+    # Check again based on the third quarter.
+    hm2 = diff_halfMatchI(longtext, shorttext, (len(longtext) + 1) // 2)
+    if not hm1 and not hm2:
+      return None
+    elif not hm2:
+      hm = hm1
+    elif not hm1:
+      hm = hm2
+    else:
+      # Both matched.  Select the longest.
+      if len(hm1[4]) > len(hm2[4]):
+        hm = hm1
+      else:
+        hm = hm2
+
+    # A half-match was found, sort out the return data.
+    if len(text1) > len(text2):
+      (text1_a, text1_b, text2_a, text2_b, mid_common) = hm
+    else:
+      (text2_a, text2_b, text1_a, text1_b, mid_common) = hm
+    return (text1_a, text1_b, text2_a, text2_b, mid_common)
+
+  def diff_cleanupSemantic(self, diffs):
+    """Reduce the number of edits by eliminating semantically trivial
+    equalities.
+
+    Args:
+      diffs: Array of diff tuples.
+    """
+    changes = False
+    equalities = []  # Stack of indices where equalities are found.
+    lastequality = None  # Always equal to diffs[equalities[-1]][1]
+    pointer = 0  # Index of current position.
+    # Number of chars that changed prior to the equality.
+    length_insertions1, length_deletions1 = 0, 0
+    # Number of chars that changed after the equality.
+    length_insertions2, length_deletions2 = 0, 0
+    while pointer < len(diffs):
+      if diffs[pointer][0] == self.DIFF_EQUAL:  # Equality found.
+        equalities.append(pointer)
+        length_insertions1, length_insertions2 = length_insertions2, 0
+        length_deletions1, length_deletions2 = length_deletions2, 0
+        lastequality = diffs[pointer][1]
+      else:  # An insertion or deletion.
+        if diffs[pointer][0] == self.DIFF_INSERT:
+          length_insertions2 += len(diffs[pointer][1])
+        else:
+          length_deletions2 += len(diffs[pointer][1])
+        # Eliminate an equality that is smaller or equal to the edits on both
+        # sides of it.
+        if (lastequality and (len(lastequality) <=
+            max(length_insertions1, length_deletions1)) and
+            (len(lastequality) <= max(length_insertions2, length_deletions2))):
+          # Duplicate record.
+          diffs.insert(equalities[-1], (self.DIFF_DELETE, lastequality))
+          # Change second copy to insert.
+          diffs[equalities[-1] + 1] = (self.DIFF_INSERT,
+              diffs[equalities[-1] + 1][1])
+          # Throw away the equality we just deleted.
+          equalities.pop()
+          # Throw away the previous equality (it needs to be reevaluated).
+          if len(equalities):
+            equalities.pop()
+          if len(equalities):
+            pointer = equalities[-1]
+          else:
+            pointer = -1
+          # Reset the counters.
+          length_insertions1, length_deletions1 = 0, 0
+          length_insertions2, length_deletions2 = 0, 0
+          lastequality = None
+          changes = True
+      pointer += 1
+
+    # Normalize the diff.
+    if changes:
+      self.diff_cleanupMerge(diffs)
+    self.diff_cleanupSemanticLossless(diffs)
+
+    # Find any overlaps between deletions and insertions.
+    # e.g: <del>abcxxx</del><ins>xxxdef</ins>
+    #   -> <del>abc</del>xxx<ins>def</ins>
+    # e.g: <del>xxxabc</del><ins>defxxx</ins>
+    #   -> <ins>def</ins>xxx<del>abc</del>
+    # Only extract an overlap if it is as big as the edit ahead or behind it.
+    pointer = 1
+    while pointer < len(diffs):
+      if (diffs[pointer - 1][0] == self.DIFF_DELETE and
+          diffs[pointer][0] == self.DIFF_INSERT):
+        deletion = diffs[pointer - 1][1]
+        insertion = diffs[pointer][1]
+        overlap_length1 = self.diff_commonOverlap(deletion, insertion)
+        overlap_length2 = self.diff_commonOverlap(insertion, deletion)
+        if overlap_length1 >= overlap_length2:
+          if (overlap_length1 >= len(deletion) / 2.0 or
+              overlap_length1 >= len(insertion) / 2.0):
+            # Overlap found.  Insert an equality and trim the surrounding edits.
+            diffs.insert(pointer, (self.DIFF_EQUAL,
+                                   insertion[:overlap_length1]))
+            diffs[pointer - 1] = (self.DIFF_DELETE,
+                                  deletion[:len(deletion) - overlap_length1])
+            diffs[pointer + 1] = (self.DIFF_INSERT,
+                                  insertion[overlap_length1:])
+            pointer += 1
+        else:
+          if (overlap_length2 >= len(deletion) / 2.0 or
+              overlap_length2 >= len(insertion) / 2.0):
+            # Reverse overlap found.
+            # Insert an equality and swap and trim the surrounding edits.
+            diffs.insert(pointer, (self.DIFF_EQUAL, deletion[:overlap_length2]))
+            diffs[pointer - 1] = (self.DIFF_INSERT,
+                                  insertion[:len(insertion) - overlap_length2])
+            diffs[pointer + 1] = (self.DIFF_DELETE, deletion[overlap_length2:])
+            pointer += 1
+        pointer += 1
+      pointer += 1
+
+  def diff_cleanupSemanticLossless(self, diffs):
+    """Look for single edits surrounded on both sides by equalities
+    which can be shifted sideways to align the edit to a word boundary.
+    e.g: The c<ins>at c</ins>ame. -> The <ins>cat </ins>came.
+
+    Args:
+      diffs: Array of diff tuples.
+    """
+
+    def diff_cleanupSemanticScore(one, two):
+      """Given two strings, compute a score representing whether the
+      internal boundary falls on logical boundaries.
+      Scores range from 6 (best) to 0 (worst).
+      Closure, but does not reference any external variables.
+
+      Args:
+        one: First string.
+        two: Second string.
+
+      Returns:
+        The score.
+      """
+      if not one or not two:
+        # Edges are the best.
+        return 6
+
+      # Each port of this function behaves slightly differently due to
+      # subtle differences in each language's definition of things like
+      # 'whitespace'.  Since this function's purpose is largely cosmetic,
+      # the choice has been made to use each language's native features
+      # rather than force total conformity.
+      char1 = one[-1]
+      char2 = two[0]
+      nonAlphaNumeric1 = not char1.isalnum()
+      nonAlphaNumeric2 = not char2.isalnum()
+      whitespace1 = nonAlphaNumeric1 and char1.isspace()
+      whitespace2 = nonAlphaNumeric2 and char2.isspace()
+      lineBreak1 = whitespace1 and (char1 == "\r" or char1 == "\n")
+      lineBreak2 = whitespace2 and (char2 == "\r" or char2 == "\n")
+      blankLine1 = lineBreak1 and self.BLANKLINEEND.search(one)
+      blankLine2 = lineBreak2 and self.BLANKLINESTART.match(two)
+
+      if blankLine1 or blankLine2:
+        # Five points for blank lines.
+        return 5
+      elif lineBreak1 or lineBreak2:
+        # Four points for line breaks.
+        return 4
+      elif nonAlphaNumeric1 and not whitespace1 and whitespace2:
+        # Three points for end of sentences.
+        return 3
+      elif whitespace1 or whitespace2:
+        # Two points for whitespace.
+        return 2
+      elif nonAlphaNumeric1 or nonAlphaNumeric2:
+        # One point for non-alphanumeric.
+        return 1
+      return 0
+
+    pointer = 1
+    # Intentionally ignore the first and last element (don't need checking).
+    while pointer < len(diffs) - 1:
+      if (diffs[pointer - 1][0] == self.DIFF_EQUAL and
+          diffs[pointer + 1][0] == self.DIFF_EQUAL):
+        # This is a single edit surrounded by equalities.
+        equality1 = diffs[pointer - 1][1]
+        edit = diffs[pointer][1]
+        equality2 = diffs[pointer + 1][1]
+
+        # First, shift the edit as far left as possible.
+        commonOffset = self.diff_commonSuffix(equality1, edit)
+        if commonOffset:
+          commonString = edit[-commonOffset:]
+          equality1 = equality1[:-commonOffset]
+          edit = commonString + edit[:-commonOffset]
+          equality2 = commonString + equality2
+
+        # Second, step character by character right, looking for the best fit.
+        bestEquality1 = equality1
+        bestEdit = edit
+        bestEquality2 = equality2
+        bestScore = (diff_cleanupSemanticScore(equality1, edit) +
+            diff_cleanupSemanticScore(edit, equality2))
+        while edit and equality2 and edit[0] == equality2[0]:
+          equality1 += edit[0]
+          edit = edit[1:] + equality2[0]
+          equality2 = equality2[1:]
+          score = (diff_cleanupSemanticScore(equality1, edit) +
+              diff_cleanupSemanticScore(edit, equality2))
+          # The >= encourages trailing rather than leading whitespace on edits.
+          if score >= bestScore:
+            bestScore = score
+            bestEquality1 = equality1
+            bestEdit = edit
+            bestEquality2 = equality2
+
+        if diffs[pointer - 1][1] != bestEquality1:
+          # We have an improvement, save it back to the diff.
+          if bestEquality1:
+            diffs[pointer - 1] = (diffs[pointer - 1][0], bestEquality1)
+          else:
+            del diffs[pointer - 1]
+            pointer -= 1
+          diffs[pointer] = (diffs[pointer][0], bestEdit)
+          if bestEquality2:
+            diffs[pointer + 1] = (diffs[pointer + 1][0], bestEquality2)
+          else:
+            del diffs[pointer + 1]
+            pointer -= 1
+      pointer += 1
+
+  # Define some regex patterns for matching boundaries.
+  BLANKLINEEND = re.compile(r"\n\r?\n$");
+  BLANKLINESTART = re.compile(r"^\r?\n\r?\n");
+
+  def diff_cleanupEfficiency(self, diffs):
+    """Reduce the number of edits by eliminating operationally trivial
+    equalities.
+
+    Args:
+      diffs: Array of diff tuples.
+    """
+    changes = False
+    equalities = []  # Stack of indices where equalities are found.
+    lastequality = None  # Always equal to diffs[equalities[-1]][1]
+    pointer = 0  # Index of current position.
+    pre_ins = False  # Is there an insertion operation before the last equality.
+    pre_del = False  # Is there a deletion operation before the last equality.
+    post_ins = False  # Is there an insertion operation after the last equality.
+    post_del = False  # Is there a deletion operation after the last equality.
+    while pointer < len(diffs):
+      if diffs[pointer][0] == self.DIFF_EQUAL:  # Equality found.
+        if (len(diffs[pointer][1]) < self.Diff_EditCost and
+            (post_ins or post_del)):
+          # Candidate found.
+          equalities.append(pointer)
+          pre_ins = post_ins
+          pre_del = post_del
+          lastequality = diffs[pointer][1]
+        else:
+          # Not a candidate, and can never become one.
+          equalities = []
+          lastequality = None
+
+        post_ins = post_del = False
+      else:  # An insertion or deletion.
+        if diffs[pointer][0] == self.DIFF_DELETE:
+          post_del = True
+        else:
+          post_ins = True
+
+        # Five types to be split:
+        # <ins>A</ins><del>B</del>XY<ins>C</ins><del>D</del>
+        # <ins>A</ins>X<ins>C</ins><del>D</del>
+        # <ins>A</ins><del>B</del>X<ins>C</ins>
+        # <ins>A</del>X<ins>C</ins><del>D</del>
+        # <ins>A</ins><del>B</del>X<del>C</del>
+
+        if lastequality and ((pre_ins and pre_del and post_ins and post_del) or
+                             ((len(lastequality) < self.Diff_EditCost / 2) and
+                              (pre_ins + pre_del + post_ins + post_del) == 3)):
+          # Duplicate record.
+          diffs.insert(equalities[-1], (self.DIFF_DELETE, lastequality))
+          # Change second copy to insert.
+          diffs[equalities[-1] + 1] = (self.DIFF_INSERT,
+              diffs[equalities[-1] + 1][1])
+          equalities.pop()  # Throw away the equality we just deleted.
+          lastequality = None
+          if pre_ins and pre_del:
+            # No changes made which could affect previous entry, keep going.
+            post_ins = post_del = True
+            equalities = []
+          else:
+            if len(equalities):
+              equalities.pop()  # Throw away the previous equality.
+            if len(equalities):
+              pointer = equalities[-1]
+            else:
+              pointer = -1
+            post_ins = post_del = False
+          changes = True
+      pointer += 1
+
+    if changes:
+      self.diff_cleanupMerge(diffs)
+
+  def diff_cleanupMerge(self, diffs):
+    """Reorder and merge like edit sections.  Merge equalities.
+    Any edit section can move as long as it doesn't cross an equality.
+
+    Args:
+      diffs: Array of diff tuples.
+    """
+    diffs.append((self.DIFF_EQUAL, ''))  # Add a dummy entry at the end.
+    pointer = 0
+    count_delete = 0
+    count_insert = 0
+    text_delete = ''
+    text_insert = ''
+    while pointer < len(diffs):
+      if diffs[pointer][0] == self.DIFF_INSERT:
+        count_insert += 1
+        text_insert += diffs[pointer][1]
+        pointer += 1
+      elif diffs[pointer][0] == self.DIFF_DELETE:
+        count_delete += 1
+        text_delete += diffs[pointer][1]
+        pointer += 1
+      elif diffs[pointer][0] == self.DIFF_EQUAL:
+        # Upon reaching an equality, check for prior redundancies.
+        if count_delete + count_insert > 1:
+          if count_delete != 0 and count_insert != 0:
+            # Factor out any common prefixies.
+            commonlength = self.diff_commonPrefix(text_insert, text_delete)
+            if commonlength != 0:
+              x = pointer - count_delete - count_insert - 1
+              if x >= 0 and diffs[x][0] == self.DIFF_EQUAL:
+                diffs[x] = (diffs[x][0], diffs[x][1] +
+                            text_insert[:commonlength])
+              else:
+                diffs.insert(0, (self.DIFF_EQUAL, text_insert[:commonlength]))
+                pointer += 1
+              text_insert = text_insert[commonlength:]
+              text_delete = text_delete[commonlength:]
+            # Factor out any common suffixies.
+            commonlength = self.diff_commonSuffix(text_insert, text_delete)
+            if commonlength != 0:
+              diffs[pointer] = (diffs[pointer][0], text_insert[-commonlength:] +
+                  diffs[pointer][1])
+              text_insert = text_insert[:-commonlength]
+              text_delete = text_delete[:-commonlength]
+          # Delete the offending records and add the merged ones.
+          if count_delete == 0:
+            diffs[pointer - count_insert : pointer] = [
+                (self.DIFF_INSERT, text_insert)]
+          elif count_insert == 0:
+            diffs[pointer - count_delete : pointer] = [
+                (self.DIFF_DELETE, text_delete)]
+          else:
+            diffs[pointer - count_delete - count_insert : pointer] = [
+                (self.DIFF_DELETE, text_delete),
+                (self.DIFF_INSERT, text_insert)]
+          pointer = pointer - count_delete - count_insert + 1
+          if count_delete != 0:
+            pointer += 1
+          if count_insert != 0:
+            pointer += 1
+        elif pointer != 0 and diffs[pointer - 1][0] == self.DIFF_EQUAL:
+          # Merge this equality with the previous one.
+          diffs[pointer - 1] = (diffs[pointer - 1][0],
+                                diffs[pointer - 1][1] + diffs[pointer][1])
+          del diffs[pointer]
+        else:
+          pointer += 1
+
+        count_insert = 0
+        count_delete = 0
+        text_delete = ''
+        text_insert = ''
+
+    if diffs[-1][1] == '':
+      diffs.pop()  # Remove the dummy entry at the end.
+
+    # Second pass: look for single edits surrounded on both sides by equalities
+    # which can be shifted sideways to eliminate an equality.
+    # e.g: A<ins>BA</ins>C -> <ins>AB</ins>AC
+    changes = False
+    pointer = 1
+    # Intentionally ignore the first and last element (don't need checking).
+    while pointer < len(diffs) - 1:
+      if (diffs[pointer - 1][0] == self.DIFF_EQUAL and
+          diffs[pointer + 1][0] == self.DIFF_EQUAL):
+        # This is a single edit surrounded by equalities.
+        if diffs[pointer][1].endswith(diffs[pointer - 1][1]):
+          # Shift the edit over the previous equality.
+          diffs[pointer] = (diffs[pointer][0],
+              diffs[pointer - 1][1] +
+              diffs[pointer][1][:-len(diffs[pointer - 1][1])])
+          diffs[pointer + 1] = (diffs[pointer + 1][0],
+                                diffs[pointer - 1][1] + diffs[pointer + 1][1])
+          del diffs[pointer - 1]
+          changes = True
+        elif diffs[pointer][1].startswith(diffs[pointer + 1][1]):
+          # Shift the edit over the next equality.
+          diffs[pointer - 1] = (diffs[pointer - 1][0],
+                                diffs[pointer - 1][1] + diffs[pointer + 1][1])
+          diffs[pointer] = (diffs[pointer][0],
+              diffs[pointer][1][len(diffs[pointer + 1][1]):] +
+              diffs[pointer + 1][1])
+          del diffs[pointer + 1]
+          changes = True
+      pointer += 1
+
+    # If shifts were made, the diff needs reordering and another shift sweep.
+    if changes:
+      self.diff_cleanupMerge(diffs)
+
+  def diff_xIndex(self, diffs, loc):
+    """loc is a location in text1, compute and return the equivalent location
+    in text2.  e.g. "The cat" vs "The big cat", 1->1, 5->8
+
+    Args:
+      diffs: Array of diff tuples.
+      loc: Location within text1.
+
+    Returns:
+      Location within text2.
+    """
+    chars1 = 0
+    chars2 = 0
+    last_chars1 = 0
+    last_chars2 = 0
+    for x in xrange(len(diffs)):
+      (op, text) = diffs[x]
+      if op != self.DIFF_INSERT:  # Equality or deletion.
+        chars1 += len(text)
+      if op != self.DIFF_DELETE:  # Equality or insertion.
+        chars2 += len(text)
+      if chars1 > loc:  # Overshot the location.
+        break
+      last_chars1 = chars1
+      last_chars2 = chars2
+
+    if len(diffs) != x and diffs[x][0] == self.DIFF_DELETE:
+      # The location was deleted.
+      return last_chars2
+    # Add the remaining len(character).
+    return last_chars2 + (loc - last_chars1)
+
+  def diff_prettyHtml(self, diffs):
+    """Convert a diff array into a pretty HTML report.
+
+    Args:
+      diffs: Array of diff tuples.
+
+    Returns:
+      HTML representation.
+    """
+    html = []
+    for (op, data) in diffs:
+      text = (data.replace("&", "&amp;").replace("<", "&lt;")
+                 .replace(">", "&gt;").replace("\n", "&para;<br>"))
+      if op == self.DIFF_INSERT:
+        html.append("<ins style=\"background:#e6ffe6;\">%s</ins>" % text)
+      elif op == self.DIFF_DELETE:
+        html.append("<del style=\"background:#ffe6e6;\">%s</del>" % text)
+      elif op == self.DIFF_EQUAL:
+        html.append("<span>%s</span>" % text)
+    return "".join(html)
+
+  def diff_text1(self, diffs):
+    """Compute and return the source text (all equalities and deletions).
+
+    Args:
+      diffs: Array of diff tuples.
+
+    Returns:
+      Source text.
+    """
+    text = []
+    for (op, data) in diffs:
+      if op != self.DIFF_INSERT:
+        text.append(data)
+    return "".join(text)
+
+  def diff_text2(self, diffs):
+    """Compute and return the destination text (all equalities and insertions).
+
+    Args:
+      diffs: Array of diff tuples.
+
+    Returns:
+      Destination text.
+    """
+    text = []
+    for (op, data) in diffs:
+      if op != self.DIFF_DELETE:
+        text.append(data)
+    return "".join(text)
+
+  def diff_levenshtein(self, diffs):
+    """Compute the Levenshtein distance; the number of inserted, deleted or
+    substituted characters.
+
+    Args:
+      diffs: Array of diff tuples.
+
+    Returns:
+      Number of changes.
+    """
+    levenshtein = 0
+    insertions = 0
+    deletions = 0
+    for (op, data) in diffs:
+      if op == self.DIFF_INSERT:
+        insertions += len(data)
+      elif op == self.DIFF_DELETE:
+        deletions += len(data)
+      elif op == self.DIFF_EQUAL:
+        # A deletion and an insertion is one substitution.
+        levenshtein += max(insertions, deletions)
+        insertions = 0
+        deletions = 0
+    levenshtein += max(insertions, deletions)
+    return levenshtein
+
+  def diff_toDelta(self, diffs):
+    """Crush the diff into an encoded string which describes the operations
+    required to transform text1 into text2.
+    E.g. =3\t-2\t+ing  -> Keep 3 chars, delete 2 chars, insert 'ing'.
+    Operations are tab-separated.  Inserted text is escaped using %xx notation.
+
+    Args:
+      diffs: Array of diff tuples.
+
+    Returns:
+      Delta text.
+    """
+    text = []
+    for (op, data) in diffs:
+      if op == self.DIFF_INSERT:
+        # High ascii will raise UnicodeDecodeError.  Use Unicode instead.
+        data = data.encode("utf-8")
+        text.append("+" + urllib.quote(data, "!~*'();/?:@&=+$,# "))
+      elif op == self.DIFF_DELETE:
+        text.append("-%d" % len(data))
+      elif op == self.DIFF_EQUAL:
+        text.append("=%d" % len(data))
+    return "\t".join(text)
+
+  def diff_fromDelta(self, text1, delta):
+    """Given the original text1, and an encoded string which describes the
+    operations required to transform text1 into text2, compute the full diff.
+
+    Args:
+      text1: Source string for the diff.
+      delta: Delta text.
+
+    Returns:
+      Array of diff tuples.
+
+    Raises:
+      ValueError: If invalid input.
+    """
+    if type(delta) == unicode:
+      # Deltas should be composed of a subset of ascii chars, Unicode not
+      # required.  If this encode raises UnicodeEncodeError, delta is invalid.
+      delta = delta.encode("ascii")
+    diffs = []
+    pointer = 0  # Cursor in text1
+    tokens = delta.split("\t")
+    for token in tokens:
+      if token == "":
+        # Blank tokens are ok (from a trailing \t).
+        continue
+      # Each token begins with a one character parameter which specifies the
+      # operation of this token (delete, insert, equality).
+      param = token[1:]
+      if token[0] == "+":
+        param = urllib.unquote(param).decode("utf-8")
+        diffs.append((self.DIFF_INSERT, param))
+      elif token[0] == "-" or token[0] == "=":
+        try:
+          n = int(param)
+        except ValueError:
+          raise ValueError("Invalid number in diff_fromDelta: " + param)
+        if n < 0:
+          raise ValueError("Negative number in diff_fromDelta: " + param)
+        text = text1[pointer : pointer + n]
+        pointer += n
+        if token[0] == "=":
+          diffs.append((self.DIFF_EQUAL, text))
+        else:
+          diffs.append((self.DIFF_DELETE, text))
+      else:
+        # Anything else is an error.
+        raise ValueError("Invalid diff operation in diff_fromDelta: " +
+            token[0])
+    if pointer != len(text1):
+      raise ValueError(
+          "Delta length (%d) does not equal source text length (%d)." %
+         (pointer, len(text1)))
+    return diffs
+
+  #  MATCH FUNCTIONS
+
+  def match_main(self, text, pattern, loc):
+    """Locate the best instance of 'pattern' in 'text' near 'loc'.
+
+    Args:
+      text: The text to search.
+      pattern: The pattern to search for.
+      loc: The location to search around.
+
+    Returns:
+      Best match index or -1.
+    """
+    # Check for null inputs.
+    if text == None or pattern == None:
+      raise ValueError("Null inputs. (match_main)")
+
+    loc = max(0, min(loc, len(text)))
+    if text == pattern:
+      # Shortcut (potentially not guaranteed by the algorithm)
+      return 0
+    elif not text:
+      # Nothing to match.
+      return -1
+    elif text[loc:loc + len(pattern)] == pattern:
+      # Perfect match at the perfect spot!  (Includes case of null pattern)
+      return loc
+    else:
+      # Do a fuzzy compare.
+      match = self.match_bitap(text, pattern, loc)
+      return match
+
+  def match_bitap(self, text, pattern, loc):
+    """Locate the best instance of 'pattern' in 'text' near 'loc' using the
+    Bitap algorithm.
+
+    Args:
+      text: The text to search.
+      pattern: The pattern to search for.
+      loc: The location to search around.
+
+    Returns:
+      Best match index or -1.
+    """
+    # Python doesn't have a maxint limit, so ignore this check.
+    #if self.Match_MaxBits != 0 and len(pattern) > self.Match_MaxBits:
+    #  raise ValueError("Pattern too long for this application.")
+
+    # Initialise the alphabet.
+    s = self.match_alphabet(pattern)
+
+    def match_bitapScore(e, x):
+      """Compute and return the score for a match with e errors and x location.
+      Accesses loc and pattern through being a closure.
+
+      Args:
+        e: Number of errors in match.
+        x: Location of match.
+
+      Returns:
+        Overall score for match (0.0 = good, 1.0 = bad).
+      """
+      accuracy = float(e) / len(pattern)
+      proximity = abs(loc - x)
+      if not self.Match_Distance:
+        # Dodge divide by zero error.
+        return proximity and 1.0 or accuracy
+      return accuracy + (proximity / float(self.Match_Distance))
+
+    # Highest score beyond which we give up.
+    score_threshold = self.Match_Threshold
+    # Is there a nearby exact match? (speedup)
+    best_loc = text.find(pattern, loc)
+    if best_loc != -1:
+      score_threshold = min(match_bitapScore(0, best_loc), score_threshold)
+      # What about in the other direction? (speedup)
+      best_loc = text.rfind(pattern, loc + len(pattern))
+      if best_loc != -1:
+        score_threshold = min(match_bitapScore(0, best_loc), score_threshold)
+
+    # Initialise the bit arrays.
+    matchmask = 1 << (len(pattern) - 1)
+    best_loc = -1
+
+    bin_max = len(pattern) + len(text)
+    # Empty initialization added to appease pychecker.
+    last_rd = None
+    for d in xrange(len(pattern)):
+      # Scan for the best match each iteration allows for one more error.
+      # Run a binary search to determine how far from 'loc' we can stray at
+      # this error level.
+      bin_min = 0
+      bin_mid = bin_max
+      while bin_min < bin_mid:
+        if match_bitapScore(d, loc + bin_mid) <= score_threshold:
+          bin_min = bin_mid
+        else:
+          bin_max = bin_mid
+        bin_mid = (bin_max - bin_min) // 2 + bin_min
+
+      # Use the result from this iteration as the maximum for the next.
+      bin_max = bin_mid
+      start = max(1, loc - bin_mid + 1)
+      finish = min(loc + bin_mid, len(text)) + len(pattern)
+
+      rd = [0] * (finish + 2)
+      rd[finish + 1] = (1 << d) - 1
+      for j in xrange(finish, start - 1, -1):
+        if len(text) <= j - 1:
+          # Out of range.
+          charMatch = 0
+        else:
+          charMatch = s.get(text[j - 1], 0)
+        if d == 0:  # First pass: exact match.
+          rd[j] = ((rd[j + 1] << 1) | 1) & charMatch
+        else:  # Subsequent passes: fuzzy match.
+          rd[j] = (((rd[j + 1] << 1) | 1) & charMatch) | (
+              ((last_rd[j + 1] | last_rd[j]) << 1) | 1) | last_rd[j + 1]
+        if rd[j] & matchmask:
+          score = match_bitapScore(d, j - 1)
+          # This match will almost certainly be better than any existing match.
+          # But check anyway.
+          if score <= score_threshold:
+            # Told you so.
+            score_threshold = score
+            best_loc = j - 1
+            if best_loc > loc:
+              # When passing loc, don't exceed our current distance from loc.
+              start = max(1, 2 * loc - best_loc)
+            else:
+              # Already passed loc, downhill from here on in.
+              break
+      # No hope for a (better) match at greater error levels.
+      if match_bitapScore(d + 1, loc) > score_threshold:
+        break
+      last_rd = rd
+    return best_loc
+
+  def match_alphabet(self, pattern):
+    """Initialise the alphabet for the Bitap algorithm.
+
+    Args:
+      pattern: The text to encode.
+
+    Returns:
+      Hash of character locations.
+    """
+    s = {}
+    for char in pattern:
+      s[char] = 0
+    for i in xrange(len(pattern)):
+      s[pattern[i]] |= 1 << (len(pattern) - i - 1)
+    return s
+
+  #  PATCH FUNCTIONS
+
+  def patch_addContext(self, patch, text):
+    """Increase the context until it is unique,
+    but don't let the pattern expand beyond Match_MaxBits.
+
+    Args:
+      patch: The patch to grow.
+      text: Source text.
+    """
+    if len(text) == 0:
+      return
+    pattern = text[patch.start2 : patch.start2 + patch.length1]
+    padding = 0
+
+    # Look for the first and last matches of pattern in text.  If two different
+    # matches are found, increase the pattern length.
+    while (text.find(pattern) != text.rfind(pattern) and (self.Match_MaxBits ==
+        0 or len(pattern) < self.Match_MaxBits - self.Patch_Margin -
+        self.Patch_Margin)):
+      padding += self.Patch_Margin
+      pattern = text[max(0, patch.start2 - padding) :
+                     patch.start2 + patch.length1 + padding]
+    # Add one chunk for good luck.
+    padding += self.Patch_Margin
+
+    # Add the prefix.
+    prefix = text[max(0, patch.start2 - padding) : patch.start2]
+    if prefix:
+      patch.diffs[:0] = [(self.DIFF_EQUAL, prefix)]
+    # Add the suffix.
+    suffix = text[patch.start2 + patch.length1 :
+                  patch.start2 + patch.length1 + padding]
+    if suffix:
+      patch.diffs.append((self.DIFF_EQUAL, suffix))
+
+    # Roll back the start points.
+    patch.start1 -= len(prefix)
+    patch.start2 -= len(prefix)
+    # Extend lengths.
+    patch.length1 += len(prefix) + len(suffix)
+    patch.length2 += len(prefix) + len(suffix)
+
+  def patch_make(self, a, b=None, c=None):
+    """Compute a list of patches to turn text1 into text2.
+    Use diffs if provided, otherwise compute it ourselves.
+    There are four ways to call this function, depending on what data is
+    available to the caller:
+    Method 1:
+    a = text1, b = text2
+    Method 2:
+    a = diffs
+    Method 3 (optimal):
+    a = text1, b = diffs
+    Method 4 (deprecated, use method 3):
+    a = text1, b = text2, c = diffs
+
+    Args:
+      a: text1 (methods 1,3,4) or Array of diff tuples for text1 to
+          text2 (method 2).
+      b: text2 (methods 1,4) or Array of diff tuples for text1 to
+          text2 (method 3) or undefined (method 2).
+      c: Array of diff tuples for text1 to text2 (method 4) or
+          undefined (methods 1,2,3).
+
+    Returns:
+      Array of Patch objects.
+    """
+    text1 = None
+    diffs = None
+    # Note that texts may arrive as 'str' or 'unicode'.
+    if isinstance(a, basestring) and isinstance(b, basestring) and c is None:
+      # Method 1: text1, text2
+      # Compute diffs from text1 and text2.
+      text1 = a
+      diffs = self.diff_main(text1, b, True)
+      if len(diffs) > 2:
+        self.diff_cleanupSemantic(diffs)
+        self.diff_cleanupEfficiency(diffs)
+    elif isinstance(a, list) and b is None and c is None:
+      # Method 2: diffs
+      # Compute text1 from diffs.
+      diffs = a
+      text1 = self.diff_text1(diffs)
+    elif isinstance(a, basestring) and isinstance(b, list) and c is None:
+      # Method 3: text1, diffs
+      text1 = a
+      diffs = b
+    elif (isinstance(a, basestring) and isinstance(b, basestring) and
+          isinstance(c, list)):
+      # Method 4: text1, text2, diffs
+      # text2 is not used.
+      text1 = a
+      diffs = c
+    else:
+      raise ValueError("Unknown call format to patch_make.")
+
+    if not diffs:
+      return []  # Get rid of the None case.
+    patches = []
+    patch = patch_obj()
+    char_count1 = 0  # Number of characters into the text1 string.
+    char_count2 = 0  # Number of characters into the text2 string.
+    prepatch_text = text1  # Recreate the patches to determine context info.
+    postpatch_text = text1
+    for x in xrange(len(diffs)):
+      (diff_type, diff_text) = diffs[x]
+      if len(patch.diffs) == 0 and diff_type != self.DIFF_EQUAL:
+        # A new patch starts here.
+        patch.start1 = char_count1
+        patch.start2 = char_count2
+      if diff_type == self.DIFF_INSERT:
+        # Insertion
+        patch.diffs.append(diffs[x])
+        patch.length2 += len(diff_text)
+        postpatch_text = (postpatch_text[:char_count2] + diff_text +
+                          postpatch_text[char_count2:])
+      elif diff_type == self.DIFF_DELETE:
+        # Deletion.
+        patch.length1 += len(diff_text)
+        patch.diffs.append(diffs[x])
+        postpatch_text = (postpatch_text[:char_count2] +
+                          postpatch_text[char_count2 + len(diff_text):])
+      elif (diff_type == self.DIFF_EQUAL and
+            len(diff_text) <= 2 * self.Patch_Margin and
+            len(patch.diffs) != 0 and len(diffs) != x + 1):
+        # Small equality inside a patch.
+        patch.diffs.append(diffs[x])
+        patch.length1 += len(diff_text)
+        patch.length2 += len(diff_text)
+
+      if (diff_type == self.DIFF_EQUAL and
+          len(diff_text) >= 2 * self.Patch_Margin):
+        # Time for a new patch.
+        if len(patch.diffs) != 0:
+          self.patch_addContext(patch, prepatch_text)
+          patches.append(patch)
+          patch = patch_obj()
+          # Unlike Unidiff, our patch lists have a rolling context.
+          # http://code.google.com/p/google-diff-match-patch/wiki/Unidiff
+          # Update prepatch text & pos to reflect the application of the
+          # just completed patch.
+          prepatch_text = postpatch_text
+          char_count1 = char_count2
+
+      # Update the current character count.
+      if diff_type != self.DIFF_INSERT:
+        char_count1 += len(diff_text)
+      if diff_type != self.DIFF_DELETE:
+        char_count2 += len(diff_text)
+
+    # Pick up the leftover patch if not empty.
+    if len(patch.diffs) != 0:
+      self.patch_addContext(patch, prepatch_text)
+      patches.append(patch)
+    return patches
+
+  def patch_deepCopy(self, patches):
+    """Given an array of patches, return another array that is identical.
+
+    Args:
+      patches: Array of Patch objects.
+
+    Returns:
+      Array of Patch objects.
+    """
+    patchesCopy = []
+    for patch in patches:
+      patchCopy = patch_obj()
+      # No need to deep copy the tuples since they are immutable.
+      patchCopy.diffs = patch.diffs[:]
+      patchCopy.start1 = patch.start1
+      patchCopy.start2 = patch.start2
+      patchCopy.length1 = patch.length1
+      patchCopy.length2 = patch.length2
+      patchesCopy.append(patchCopy)
+    return patchesCopy
+
+  def patch_apply(self, patches, text):
+    """Merge a set of patches onto the text.  Return a patched text, as well
+    as a list of true/false values indicating which patches were applied.
+
+    Args:
+      patches: Array of Patch objects.
+      text: Old text.
+
+    Returns:
+      Two element Array, containing the new text and an array of boolean values.
+    """
+    if not patches:
+      return (text, [])
+
+    # Deep copy the patches so that no changes are made to originals.
+    patches = self.patch_deepCopy(patches)
+
+    nullPadding = self.patch_addPadding(patches)
+    text = nullPadding + text + nullPadding
+    self.patch_splitMax(patches)
+
+    # delta keeps track of the offset between the expected and actual location
+    # of the previous patch.  If there are patches expected at positions 10 and
+    # 20, but the first patch was found at 12, delta is 2 and the second patch
+    # has an effective expected position of 22.
+    delta = 0
+    results = []
+    for patch in patches:
+      expected_loc = patch.start2 + delta
+      text1 = self.diff_text1(patch.diffs)
+      end_loc = -1
+      if len(text1) > self.Match_MaxBits:
+        # patch_splitMax will only provide an oversized pattern in the case of
+        # a monster delete.
+        start_loc = self.match_main(text, text1[:self.Match_MaxBits],
+                                    expected_loc)
+        if start_loc != -1:
+          end_loc = self.match_main(text, text1[-self.Match_MaxBits:],
+              expected_loc + len(text1) - self.Match_MaxBits)
+          if end_loc == -1 or start_loc >= end_loc:
+            # Can't find valid trailing context.  Drop this patch.
+            start_loc = -1
+      else:
+        start_loc = self.match_main(text, text1, expected_loc)
+      if start_loc == -1:
+        # No match found.  :(
+        results.append(False)
+        # Subtract the delta for this failed patch from subsequent patches.
+        delta -= patch.length2 - patch.length1
+      else:
+        # Found a match.  :)
+        results.append(True)
+        delta = start_loc - expected_loc
+        if end_loc == -1:
+          text2 = text[start_loc : start_loc + len(text1)]
+        else:
+          text2 = text[start_loc : end_loc + self.Match_MaxBits]
+        if text1 == text2:
+          # Perfect match, just shove the replacement text in.
+          text = (text[:start_loc] + self.diff_text2(patch.diffs) +
+                      text[start_loc + len(text1):])
+        else:
+          # Imperfect match.
+          # Run a diff to get a framework of equivalent indices.
+          diffs = self.diff_main(text1, text2, False)
+          if (len(text1) > self.Match_MaxBits and
+              self.diff_levenshtein(diffs) / float(len(text1)) >
+              self.Patch_DeleteThreshold):
+            # The end points match, but the content is unacceptably bad.
+            results[-1] = False
+          else:
+            self.diff_cleanupSemanticLossless(diffs)
+            index1 = 0
+            for (op, data) in patch.diffs:
+              if op != self.DIFF_EQUAL:
+                index2 = self.diff_xIndex(diffs, index1)
+              if op == self.DIFF_INSERT:  # Insertion
+                text = text[:start_loc + index2] + data + text[start_loc +
+                                                               index2:]
+              elif op == self.DIFF_DELETE:  # Deletion
+                text = text[:start_loc + index2] + text[start_loc +
+                    self.diff_xIndex(diffs, index1 + len(data)):]
+              if op != self.DIFF_DELETE:
+                index1 += len(data)
+    # Strip the padding off.
+    text = text[len(nullPadding):-len(nullPadding)]
+    return (text, results)
+
+  def patch_addPadding(self, patches):
+    """Add some padding on text start and end so that edges can match
+    something.  Intended to be called only from within patch_apply.
+
+    Args:
+      patches: Array of Patch objects.
+
+    Returns:
+      The padding string added to each side.
+    """
+    paddingLength = self.Patch_Margin
+    nullPadding = ""
+    for x in xrange(1, paddingLength + 1):
+      nullPadding += chr(x)
+
+    # Bump all the patches forward.
+    for patch in patches:
+      patch.start1 += paddingLength
+      patch.start2 += paddingLength
+
+    # Add some padding on start of first diff.
+    patch = patches[0]
+    diffs = patch.diffs
+    if not diffs or diffs[0][0] != self.DIFF_EQUAL:
+      # Add nullPadding equality.
+      diffs.insert(0, (self.DIFF_EQUAL, nullPadding))
+      patch.start1 -= paddingLength  # Should be 0.
+      patch.start2 -= paddingLength  # Should be 0.
+      patch.length1 += paddingLength
+      patch.length2 += paddingLength
+    elif paddingLength > len(diffs[0][1]):
+      # Grow first equality.
+      extraLength = paddingLength - len(diffs[0][1])
+      newText = nullPadding[len(diffs[0][1]):] + diffs[0][1]
+      diffs[0] = (diffs[0][0], newText)
+      patch.start1 -= extraLength
+      patch.start2 -= extraLength
+      patch.length1 += extraLength
+      patch.length2 += extraLength
+
+    # Add some padding on end of last diff.
+    patch = patches[-1]
+    diffs = patch.diffs
+    if not diffs or diffs[-1][0] != self.DIFF_EQUAL:
+      # Add nullPadding equality.
+      diffs.append((self.DIFF_EQUAL, nullPadding))
+      patch.length1 += paddingLength
+      patch.length2 += paddingLength
+    elif paddingLength > len(diffs[-1][1]):
+      # Grow last equality.
+      extraLength = paddingLength - len(diffs[-1][1])
+      newText = diffs[-1][1] + nullPadding[:extraLength]
+      diffs[-1] = (diffs[-1][0], newText)
+      patch.length1 += extraLength
+      patch.length2 += extraLength
+
+    return nullPadding
+
+  def patch_splitMax(self, patches):
+    """Look through the patches and break up any which are longer than the
+    maximum limit of the match algorithm.
+    Intended to be called only from within patch_apply.
+
+    Args:
+      patches: Array of Patch objects.
+    """
+    patch_size = self.Match_MaxBits
+    if patch_size == 0:
+      # Python has the option of not splitting strings due to its ability
+      # to handle integers of arbitrary precision.
+      return
+    for x in xrange(len(patches)):
+      if patches[x].length1 <= patch_size:
+        continue
+      bigpatch = patches[x]
+      # Remove the big old patch.
+      del patches[x]
+      x -= 1
+      start1 = bigpatch.start1
+      start2 = bigpatch.start2
+      precontext = ''
+      while len(bigpatch.diffs) != 0:
+        # Create one of several smaller patches.
+        patch = patch_obj()
+        empty = True
+        patch.start1 = start1 - len(precontext)
+        patch.start2 = start2 - len(precontext)
+        if precontext:
+          patch.length1 = patch.length2 = len(precontext)
+          patch.diffs.append((self.DIFF_EQUAL, precontext))
+
+        while (len(bigpatch.diffs) != 0 and
+               patch.length1 < patch_size - self.Patch_Margin):
+          (diff_type, diff_text) = bigpatch.diffs[0]
+          if diff_type == self.DIFF_INSERT:
+            # Insertions are harmless.
+            patch.length2 += len(diff_text)
+            start2 += len(diff_text)
+            patch.diffs.append(bigpatch.diffs.pop(0))
+            empty = False
+          elif (diff_type == self.DIFF_DELETE and len(patch.diffs) == 1 and
+              patch.diffs[0][0] == self.DIFF_EQUAL and
+              len(diff_text) > 2 * patch_size):
+            # This is a large deletion.  Let it pass in one chunk.
+            patch.length1 += len(diff_text)
+            start1 += len(diff_text)
+            empty = False
+            patch.diffs.append((diff_type, diff_text))
+            del bigpatch.diffs[0]
+          else:
+            # Deletion or equality.  Only take as much as we can stomach.
+            diff_text = diff_text[:patch_size - patch.length1 -
+                                  self.Patch_Margin]
+            patch.length1 += len(diff_text)
+            start1 += len(diff_text)
+            if diff_type == self.DIFF_EQUAL:
+              patch.length2 += len(diff_text)
+              start2 += len(diff_text)
+            else:
+              empty = False
+
+            patch.diffs.append((diff_type, diff_text))
+            if diff_text == bigpatch.diffs[0][1]:
+              del bigpatch.diffs[0]
+            else:
+              bigpatch.diffs[0] = (bigpatch.diffs[0][0],
+                                   bigpatch.diffs[0][1][len(diff_text):])
+
+        # Compute the head context for the next patch.
+        precontext = self.diff_text2(patch.diffs)
+        precontext = precontext[-self.Patch_Margin:]
+        # Append the end context for this patch.
+        postcontext = self.diff_text1(bigpatch.diffs)[:self.Patch_Margin]
+        if postcontext:
+          patch.length1 += len(postcontext)
+          patch.length2 += len(postcontext)
+          if len(patch.diffs) != 0 and patch.diffs[-1][0] == self.DIFF_EQUAL:
+            patch.diffs[-1] = (self.DIFF_EQUAL, patch.diffs[-1][1] +
+                               postcontext)
+          else:
+            patch.diffs.append((self.DIFF_EQUAL, postcontext))
+
+        if not empty:
+          x += 1
+          patches.insert(x, patch)
+
+  def patch_toText(self, patches):
+    """Take a list of patches and return a textual representation.
+
+    Args:
+      patches: Array of Patch objects.
+
+    Returns:
+      Text representation of patches.
+    """
+    text = []
+    for patch in patches:
+      text.append(str(patch))
+    return "".join(text)
+
+  def patch_fromText(self, textline):
+    """Parse a textual representation of patches and return a list of patch
+    objects.
+
+    Args:
+      textline: Text representation of patches.
+
+    Returns:
+      Array of Patch objects.
+
+    Raises:
+      ValueError: If invalid input.
+    """
+    if type(textline) == unicode:
+      # Patches should be composed of a subset of ascii chars, Unicode not
+      # required.  If this encode raises UnicodeEncodeError, patch is invalid.
+      textline = textline.encode("ascii")
+    patches = []
+    if not textline:
+      return patches
+    text = textline.split('\n')
+    while len(text) != 0:
+      m = re.match("^@@ -(\d+),?(\d*) \+(\d+),?(\d*) @@$", text[0])
+      if not m:
+        raise ValueError("Invalid patch string: " + text[0])
+      patch = patch_obj()
+      patches.append(patch)
+      patch.start1 = int(m.group(1))
+      if m.group(2) == '':
+        patch.start1 -= 1
+        patch.length1 = 1
+      elif m.group(2) == '0':
+        patch.length1 = 0
+      else:
+        patch.start1 -= 1
+        patch.length1 = int(m.group(2))
+
+      patch.start2 = int(m.group(3))
+      if m.group(4) == '':
+        patch.start2 -= 1
+        patch.length2 = 1
+      elif m.group(4) == '0':
+        patch.length2 = 0
+      else:
+        patch.start2 -= 1
+        patch.length2 = int(m.group(4))
+
+      del text[0]
+
+      while len(text) != 0:
+        if text[0]:
+          sign = text[0][0]
+        else:
+          sign = ''
+        line = urllib.unquote(text[0][1:])
+        line = line.decode("utf-8")
+        if sign == '+':
+          # Insertion.
+          patch.diffs.append((self.DIFF_INSERT, line))
+        elif sign == '-':
+          # Deletion.
+          patch.diffs.append((self.DIFF_DELETE, line))
+        elif sign == ' ':
+          # Minor equality.
+          patch.diffs.append((self.DIFF_EQUAL, line))
+        elif sign == '@':
+          # Start of next patch.
+          break
+        elif sign == '':
+          # Blank line?  Whatever.
+          pass
+        else:
+          # WTF?
+          raise ValueError("Invalid patch mode: '%s'\n%s" % (sign, line))
+        del text[0]
+    return patches
+
+
+class patch_obj:
+  """Class representing one patch operation.
+  """
+
+  def __init__(self):
+    """Initializes with an empty list of diffs.
+    """
+    self.diffs = []
+    self.start1 = None
+    self.start2 = None
+    self.length1 = 0
+    self.length2 = 0
+
+  def __str__(self):
+    """Emmulate GNU diff's format.
+    Header: @@ -382,8 +481,9 @@
+    Indicies are printed as 1-based, not 0-based.
+
+    Returns:
+      The GNU diff string.
+    """
+    if self.length1 == 0:
+      coords1 = str(self.start1) + ",0"
+    elif self.length1 == 1:
+      coords1 = str(self.start1 + 1)
+    else:
+      coords1 = str(self.start1 + 1) + "," + str(self.length1)
+    if self.length2 == 0:
+      coords2 = str(self.start2) + ",0"
+    elif self.length2 == 1:
+      coords2 = str(self.start2 + 1)
+    else:
+      coords2 = str(self.start2 + 1) + "," + str(self.length2)
+    text = ["@@ -", coords1, " +", coords2, " @@\n"]
+    # Escape the body of the patch with %xx notation.
+    for (op, data) in self.diffs:
+      if op == diff_match_patch.DIFF_INSERT:
+        text.append("+")
+      elif op == diff_match_patch.DIFF_DELETE:
+        text.append("-")
+      elif op == diff_match_patch.DIFF_EQUAL:
+        text.append(" ")
+      # High ascii will raise UnicodeDecodeError.  Use Unicode instead.
+      data = data.encode("utf-8")
+      text.append(urllib.quote(data, "!~*'();/?:@&=+$,# ") + "\n")
+    return "".join(text)
  No newline at end of file

rhodecode/templates/codeblocks/diffs.html

@@ -0,0 +1,398 b''
+<%def name="diff_line_anchor(filename, line, type)"><%
+return '%s_%s_%i' % (h.safeid(filename), type, line)
+%></%def>
+
+<%def name="action_class(action)"><%
+    return {
+        '-': 'cb-deletion',
+        '+': 'cb-addition',
+        ' ': 'cb-context',
+        }.get(action, 'cb-empty')
+%></%def>
+
+<%def name="op_class(op_id)"><%
+    return {
+        DEL_FILENODE: 'deletion', # file deleted
+        BIN_FILENODE: 'warning' # binary diff hidden
+    }.get(op_id, 'addition')
+%></%def>
+
+<%def name="link_for(**kw)"><%
+new_args = request.GET.mixed()
+new_args.update(kw)
+return h.url('', **new_args)
+%></%def>
+
+<%def name="render_diffset(diffset,
+
+    # collapse all file diff entries when there are more than this amount of files in the diff
+    collapse_when_files_over=20,
+
+    # collapse lines in the diff when more than this amount of lines changed in the file diff
+    lines_changed_limit=500,
+)">
+<%
+# TODO: dan: move this to an argument - and set a cookie so that it is saved
+# default option for future requests
+diff_mode = request.GET.get('diffmode', 'sideside')
+if diff_mode not in ('sideside', 'unified'):
+    diff_mode = 'sideside'
+
+collapse_all = len(diffset.files) > collapse_when_files_over
+%>
+
+%if diff_mode == 'sideside':
+<style>
+.wrapper {
+    max-width: 1600px !important;
+}
+</style>
+%endif
+
+% if diffset.limited_diff:
+<div class="alert alert-warning">
+    ${_('The requested commit is too big and content was truncated.')} <a href="${link_for(fulldiff=1)}" onclick="return confirm('${_("Showing a big diff might take some time and resources, continue?")}')">${_('Show full diff')}</a>
+</div>
+% endif
+
+<div class="cs_files">
+    <div class="cs_files_title">
+        %if diffset.files:
+        <div class="pull-right">
+            <div class="btn-group">
+                <a
+                    class="btn ${diff_mode == 'sideside' and 'btn-primary'} tooltip"
+                    title="${_('View side by side')}"
+                    href="${link_for(diffmode='sideside')}">
+                    <span>${_('Side by Side')}</span>
+                </a>
+                <a
+                    class="btn ${diff_mode == 'unified' and 'btn-primary'} tooltip"
+                    title="${_('View unified')}" href="${link_for(diffmode='unified')}">
+                    <span>${_('Unified')}</span>
+                </a>
+            </div>
+        </div>
+        <div class="pull-left">
+            <div class="btn-group">
+                <a
+                    class="btn"
+                    href="#"
+                    onclick="$('input[class=diff-collapse-state]').prop('checked', false); return false">${_('Expand All')}</a>
+                <a
+                    class="btn"
+                    href="#"
+                    onclick="$('input[class=diff-collapse-state]').prop('checked', true); return false">${_('Collapse All')}</a>
+            </div>
+        </div>
+        %endif
+        <h2 style="padding: 5px; text-align: center;">
+    %if diffset.limited_diff:
+        ${ungettext('%(num)s file changed', '%(num)s files changed', diffset.changed_files) % {'num': diffset.changed_files}}
+    %else:
+        ${ungettext('%(num)s file changed: %(linesadd)s inserted, ''%(linesdel)s deleted',
+                    '%(num)s files changed: %(linesadd)s inserted, %(linesdel)s deleted', diffset.changed_files) % {'num': diffset.changed_files, 'linesadd': diffset.lines_added, 'linesdel': diffset.lines_deleted}}
+    %endif
+        </h2>
+    </div>
+
+    %if not diffset.files:
+        <p class="empty_data">${_('No files')}</p>
+    %endif
+
+    <div class="filediffs">
+    %for i, filediff in enumerate(diffset.files):
+    <%
+    lines_changed = filediff['patch']['stats']['added'] + filediff['patch']['stats']['deleted']
+    over_lines_changed_limit = lines_changed > lines_changed_limit
+    %>
+        <input ${collapse_all and 'checked' or ''} class="diff-collapse-state" id="diff-collapse-${i}" type="checkbox">
+        <div
+            class="diff"
+            data-f-path="${filediff['patch']['filename']}"
+            id="a_${h.FID('', filediff['patch']['filename'])}">
+            <label for="diff-collapse-${i}" class="diff-heading">
+                <div class="diff-collapse-indicator"></div>
+                ${diff_ops(filediff)}
+            </label>
+            ${diff_menu(filediff)}
+            <table class="cb cb-diff-${diff_mode} code-highlight ${over_lines_changed_limit and 'cb-collapsed' or ''}">
+        %if not filediff.hunks:
+            %for op_id, op_text in filediff['patch']['stats']['ops'].items():
+                <tr>
+                    <td class="cb-text cb-${op_class(op_id)}" ${diff_mode == 'unified' and 'colspan=3' or 'colspan=4'}>
+                        %if op_id == DEL_FILENODE:
+                        ${_('File was deleted')}
+                        %elif op_id == BIN_FILENODE:
+                        ${_('Binary file hidden')}
+                        %else:
+                        ${op_text}
+                        %endif
+                    </td>
+                </tr>
+            %endfor
+        %endif
+        %if over_lines_changed_limit:
+                <tr class="cb-warning cb-collapser">
+                    <td class="cb-text" ${diff_mode == 'unified' and 'colspan=3' or 'colspan=4'}>
+                        ${_('This diff has been collapsed as it changes many lines, (%i lines changed)' % lines_changed)}
+                        <a href="#" class="cb-expand"
+                           onclick="$(this).closest('table').removeClass('cb-collapsed'); return false;">${_('Show them')}
+                        </a>
+                        <a href="#" class="cb-collapse"
+                           onclick="$(this).closest('table').addClass('cb-collapsed'); return false;">${_('Hide them')}
+                        </a>
+                    </td>
+                </tr>
+        %endif
+        %if filediff.patch['is_limited_diff']:
+                <tr class="cb-warning cb-collapser">
+                    <td class="cb-text" ${diff_mode == 'unified' and 'colspan=3' or 'colspan=4'}>
+                        ${_('The requested commit is too big and content was truncated.')} <a href="${link_for(fulldiff=1)}" onclick="return confirm('${_("Showing a big diff might take some time and resources, continue?")}')">${_('Show full diff')}</a>
+                    </td>
+                </tr>
+        %endif
+        %for hunk in filediff.hunks:
+                <tr class="cb-hunk">
+                    <td ${diff_mode == 'unified' and 'colspan=2' or ''}>
+                        ## TODO: dan: add ajax loading of more context here
+                        ## <a href="#">
+                            <i class="icon-more"></i>
+                        ## </a>
+                    </td>
+                    <td ${diff_mode == 'sideside' and 'colspan=3' or ''}>
+                        @@
+                        -${hunk.source_start},${hunk.source_length}
+                        +${hunk.target_start},${hunk.target_length}
+                        ${hunk.section_header}
+                    </td>
+                </tr>
+            %if diff_mode == 'unified':
+                    ${render_hunk_lines_unified(hunk)}
+            %elif diff_mode == 'sideside':
+                    ${render_hunk_lines_sideside(hunk)}
+            %else:
+                <tr class="cb-line">
+                    <td>unknown diff mode</td>
+                </tr>
+            %endif
+        %endfor
+            </table>
+        </div>
+    %endfor
+    </div>
+</div>
+</%def>
+
+<%def name="diff_ops(filediff)">
+<%
+stats = filediff['patch']['stats']
+from rhodecode.lib.diffs import NEW_FILENODE, DEL_FILENODE, \
+    MOD_FILENODE, RENAMED_FILENODE, CHMOD_FILENODE, BIN_FILENODE
+%>
+    <span class="diff-pill">
+        %if filediff.source_file_path and filediff.target_file_path:
+            %if filediff.source_file_path != filediff.target_file_path: # file was renamed
+                  <strong>${filediff.target_file_path}</strong> ⬅ <del>${filediff.source_file_path}</del>
+            %else:
+                ## file was modified
+                <strong>${filediff.source_file_path}</strong>
+            %endif
+        %else:
+            %if filediff.source_file_path:
+                ## file was deleted
+                <strong>${filediff.source_file_path}</strong>
+            %else:
+                ## file was added
+                <strong>${filediff.target_file_path}</strong>
+            %endif
+        %endif
+    </span>
+    <span class="diff-pill-group" style="float: left">
+        %if filediff.patch['is_limited_diff']:
+        <span class="diff-pill tooltip" op="limited" title="The stats for this diff are not complete">limited diff</span>
+        %endif
+        %if RENAMED_FILENODE in stats['ops']:
+        <span class="diff-pill" op="renamed">renamed</span>
+        %endif
+
+        %if NEW_FILENODE in stats['ops']:
+        <span class="diff-pill" op="created">created</span>
+            %if filediff['target_mode'].startswith('120'):
+        <span class="diff-pill" op="symlink">symlink</span>
+            %else:
+        <span class="diff-pill" op="mode">${nice_mode(filediff['target_mode'])}</span>
+            %endif
+        %endif
+
+        %if DEL_FILENODE in stats['ops']:
+        <span class="diff-pill" op="removed">removed</span>
+        %endif
+
+        %if CHMOD_FILENODE in stats['ops']:
+        <span class="diff-pill" op="mode">
+            ${nice_mode(filediff['source_mode'])} ➡ ${nice_mode(filediff['target_mode'])}
+        </span>
+        %endif
+    </span>
+
+    <a class="diff-pill diff-anchor" href="#a_${h.FID('', filediff.patch['filename'])}">¶</a>
+
+    <span class="diff-pill-group" style="float: right">
+        %if BIN_FILENODE in stats['ops']:
+        <span class="diff-pill" op="binary">binary</span>
+            %if MOD_FILENODE in stats['ops']:
+            <span class="diff-pill" op="modified">modified</span>
+            %endif
+        %endif
+        %if stats['deleted']:
+        <span class="diff-pill" op="deleted">-${stats['deleted']}</span>
+        %endif
+        %if stats['added']:
+        <span class="diff-pill" op="added">+${stats['added']}</span>
+        %endif
+    </span>
+
+</%def>
+
+<%def name="nice_mode(filemode)">
+    ${filemode.startswith('100') and filemode[3:] or filemode}
+</%def>
+
+<%def name="diff_menu(filediff)">
+    <div class="diff-menu">
+%if filediff.diffset.source_ref:
+    %if filediff.patch['operation'] in ['D', 'M']:
+        <a
+            class="tooltip"
+            href="${h.url('files_home',repo_name=c.repo_name,f_path=filediff.source_file_path,revision=filediff.diffset.source_ref)}"
+            title="${h.tooltip(_('Show file at commit: %(commit_id)s') % {'commit_id': filediff.diffset.source_ref[:12]})}"
+        >
+            ${_('Show file before')}
+        </a>
+    %else:
+        <a
+            disabled
+            class="tooltip"
+            title="${h.tooltip(_('File no longer present at commit: %(commit_id)s') % {'commit_id': filediff.diffset.source_ref[:12]})}"
+        >
+            ${_('Show file before')}
+        </a>
+    %endif
+    %if filediff.patch['operation'] in ['A', 'M']:
+        <a
+            class="tooltip"
+            href="${h.url('files_home',repo_name=c.repo_name,f_path=filediff.target_file_path,revision=filediff.diffset.target_ref)}"
+            title="${h.tooltip(_('Show file at commit: %(commit_id)s') % {'commit_id': filediff.diffset.target_ref[:12]})}"
+        >
+            ${_('Show file after')}
+        </a>
+    %else:
+        <a
+            disabled
+            class="tooltip"
+            title="${h.tooltip(_('File no longer present at commit: %(commit_id)s') % {'commit_id': filediff.diffset.target_ref[:12]})}"
+            >
+                ${_('Show file after')}
+        </a>
+    %endif
+        <a
+            class="tooltip"
+            title="${h.tooltip(_('Raw diff'))}"
+            href="${h.url('files_diff_home',repo_name=c.repo_name,f_path=filediff.target_file_path,diff2=filediff.diffset.target_ref,diff1=filediff.diffset.source_ref,diff='raw')}"
+        >
+            ${_('Raw diff')}
+        </a>
+        <a
+            class="tooltip"
+            title="${h.tooltip(_('Download diff'))}"
+            href="${h.url('files_diff_home',repo_name=c.repo_name,f_path=filediff.target_file_path,diff2=filediff.diffset.target_ref,diff1=filediff.diffset.source_ref,diff='download')}"
+        >
+            ${_('Download diff')}
+        </a>
+%endif
+    </div>
+</%def>
+
+
+<%def name="render_hunk_lines_sideside(hunk)">
+    %for i, line in enumerate(hunk.sideside):
+    <%
+    old_line_anchor, new_line_anchor = None, None
+    if line.original.lineno:
+        old_line_anchor = diff_line_anchor(hunk.filediff.source_file_path, line.original.lineno, 'o')
+    if line.modified.lineno:
+        new_line_anchor = diff_line_anchor(hunk.filediff.target_file_path, line.modified.lineno, 'n')
+    %>
+    <tr class="cb-line">
+        <td class="cb-lineno ${action_class(line.original.action)}"
+            data-line-number="${line.original.lineno}"
+            %if old_line_anchor:
+            id="${old_line_anchor}"
+            %endif
+        >
+            %if line.original.lineno:
+            <a name="${old_line_anchor}" href="#${old_line_anchor}">${line.original.lineno}</a>
+            %endif
+        </td>
+        <td class="cb-content ${action_class(line.original.action)}"
+            data-line-number="o${line.original.lineno}"
+            ><span class="cb-code">${line.original.action} ${line.original.content or '' | n}</span>
+        </td>
+        <td class="cb-lineno ${action_class(line.modified.action)}"
+            data-line-number="${line.modified.lineno}"
+            %if new_line_anchor:
+            id="${new_line_anchor}"
+            %endif
+            >
+            %if line.modified.lineno:
+                <a name="${new_line_anchor}" href="#${new_line_anchor}">${line.modified.lineno}</a>
+            %endif
+            </td>
+        <td class="cb-content ${action_class(line.modified.action)}"
+            data-line-number="n${line.modified.lineno}"
+            >
+            <span class="cb-code">${line.modified.action} ${line.modified.content or '' | n}</span>
+        </td>
+    </tr>
+    %endfor
+</%def>
+
+
+<%def name="render_hunk_lines_unified(hunk)">
+    %for old_line_no, new_line_no, action, content in hunk.unified:
+    <%
+    old_line_anchor, new_line_anchor = None, None
+    if old_line_no:
+        old_line_anchor = diff_line_anchor(hunk.filediff.source_file_path, old_line_no, 'o')
+    if new_line_no:
+        new_line_anchor = diff_line_anchor(hunk.filediff.target_file_path, new_line_no, 'n')
+    %>
+    <tr class="cb-line">
+        <td class="cb-lineno ${action_class(action)}"
+            data-line-number="${old_line_no}"
+            %if old_line_anchor:
+            id="${old_line_anchor}"
+            %endif
+        >
+            %if old_line_anchor:
+            <a name="${old_line_anchor}" href="#${old_line_anchor}">${old_line_no}</a>
+            %endif
+        </td>
+        <td class="cb-lineno ${action_class(action)}"
+            data-line-number="${new_line_no}"
+            %if new_line_anchor:
+            id="${new_line_anchor}"
+            %endif
+        >
+            %if new_line_anchor:
+            <a name="${new_line_anchor}" href="#${new_line_anchor}">${new_line_no}</a>
+            %endif
+        </td>
+        <td class="cb-content ${action_class(action)}"
+            data-line-number="${new_line_no and 'n' or 'o'}${new_line_no or old_line_no}"
+            ><span class="cb-code">${action} ${content or '' | n}</span>
+          </td>
+    </tr>
+    %endfor
+</%def>

LICENSE.txt

@@ -14,6 +14,8 b' permission notice:'
        file:licenses/tornado_license.txt
    Copyright (c) 2015 - pygments-markdown-lexer
        file:licenses/pygments_markdown_lexer_license.txt
+   Copyright 2006 - diff_match_patch
+       file:licenses/diff_match_patch_license.txt
 
 All licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.

rhodecode/controllers/compare.py

@@ -31,13 +31,14 b' from pylons.i18n.translation import _'
 
 from rhodecode.controllers.utils import parse_path_ref, get_commit_from_ref_name
 from rhodecode.lib import helpers as h
-from rhodecode.lib import diffs
+from rhodecode.lib import diffs, codeblocks
 from rhodecode.lib.auth import LoginRequired, HasRepoPermissionAnyDecorator
 from rhodecode.lib.base import BaseRepoController, render
 from rhodecode.lib.utils import safe_str
 from rhodecode.lib.utils2 import safe_unicode, str2bool
 from rhodecode.lib.vcs.exceptions import (
-    EmptyRepositoryError, RepositoryError, RepositoryRequirementError)
+    EmptyRepositoryError, RepositoryError, RepositoryRequirementError,
+    NodeDoesNotExistError)
 from rhodecode.model.db import Repository, ChangesetStatus
 
 log = logging.getLogger(__name__)
@@ -78,7 +79,7 b' class CompareController(BaseRepoControll'
     def index(self, repo_name):
         c.compare_home = True
         c.commit_ranges = []
-        c.files = []
+        c.diffset = None
         c.limited_diff = False
         source_repo = c.rhodecode_db_repo.repo_name
         target_repo = request.GET.get('target_repo', source_repo)
@@ -239,28 +240,23 b' class CompareController(BaseRepoControll'
             commit1=source_commit, commit2=target_commit,
             path1=source_path, path=target_path)
         diff_processor = diffs.DiffProcessor(
-            txtdiff, format='gitdiff', diff_limit=diff_limit,
+            txtdiff, format='newdiff', diff_limit=diff_limit,
             file_limit=file_limit, show_full_diff=c.fulldiff)
         _parsed = diff_processor.prepare()
 
-        c.limited_diff = False
-        if isinstance(_parsed, diffs.LimitedDiffContainer):
-            c.limited_diff = True
+        def _node_getter(commit):
+            """ Returns a function that returns a node for a commit or None """
+            def get_node(fname):
+                try:
+                    return commit.get_node(fname)
+                except NodeDoesNotExistError:
+                    return None
+            return get_node
 
-        c.files = []
-        c.changes = {}
-        c.lines_added = 0
-        c.lines_deleted = 0
-        for f in _parsed:
-            st = f['stats']
-            if not st['binary']:
-                c.lines_added += st['added']
-                c.lines_deleted += st['deleted']
-            fid = h.FID('', f['filename'])
-            c.files.append([fid, f['operation'], f['filename'], f['stats'], f])
-            htmldiff = diff_processor.as_html(
-                enable_comments=False, parsed_lines=[f])
-            c.changes[fid] = [f['operation'], f['filename'], htmldiff, f]
+        c.diffset = codeblocks.DiffSet(
+            source_node_getter=_node_getter(source_commit),
+            target_node_getter=_node_getter(target_commit),
+        ).render_patchset(_parsed, source_ref, target_ref)
 
         c.preview_mode = merge
 

rhodecode/lib/codeblocks.py

@@ -19,13 +19,17 b''
 # and proprietary license terms, please see https://rhodecode.com/licenses/
 
 import logging
+import difflib
 from itertools import groupby
 
 from pygments import lex
 from pygments.formatters.html import _get_ttype_class as pygment_token_class
-from rhodecode.lib.helpers import get_lexer_for_filenode, html_escape
+from rhodecode.lib.helpers import (
+    get_lexer_for_filenode, get_lexer_safe, html_escape)
 from rhodecode.lib.utils2 import AttributeDict
 from rhodecode.lib.vcs.nodes import FileNode
+from rhodecode.lib.diff_match_patch import diff_match_patch
+from rhodecode.lib.diffs import LimitedDiffContainer
 from pygments.lexers import get_lexer_by_name
 
 plain_text_lexer = get_lexer_by_name(
@@ -38,7 +42,7 b' log = logging.getLogger()'
 def filenode_as_lines_tokens(filenode, lexer=None):
     lexer = lexer or get_lexer_for_filenode(filenode)
     log.debug('Generating file node pygment tokens for %s, %s', lexer, filenode)
-    tokens = tokenize_string(filenode.content, get_lexer_for_filenode(filenode))
+    tokens = tokenize_string(filenode.content, lexer)
     lines = split_token_stream(tokens, split_string='\n')
     rv = list(lines)
     return rv
@@ -146,7 +150,11 b' def render_tokenstream(tokenstream):'
                 result.append(u'<%s>' % op_tag)
 
             escaped_text = html_escape(token_text)
-            escaped_text = escaped_text.replace('\n', '<nl>\n</nl>')
+
+            # TODO: dan: investigate showing hidden characters like space/nl/tab
+            # escaped_text = escaped_text.replace(' ', '<sp> </sp>')
+            # escaped_text = escaped_text.replace('\n', '<nl>\n</nl>')
+            # escaped_text = escaped_text.replace('\t', '<tab>\t</tab>')
 
             result.append(escaped_text)
 
@@ -212,3 +220,416 b' def rollup_tokenstream(tokenstream):'
             ops.append((token_op, ''.join(text_buffer)))
         result.append((token_class, ops))
     return result
+
+
+def tokens_diff(old_tokens, new_tokens, use_diff_match_patch=True):
+    """
+    Converts a list of (token_class, token_text) tuples to a list of
+    (token_class, token_op, token_text) tuples where token_op is one of
+    ('ins', 'del', '')
+
+    :param old_tokens: list of (token_class, token_text) tuples of old line
+    :param new_tokens: list of (token_class, token_text) tuples of new line
+    :param use_diff_match_patch: boolean, will use google's diff match patch
+        library which has options to 'smooth' out the character by character
+        differences making nicer ins/del blocks
+    """
+
+    old_tokens_result = []
+    new_tokens_result = []
+
+    similarity = difflib.SequenceMatcher(None,
+        ''.join(token_text for token_class, token_text in old_tokens),
+        ''.join(token_text for token_class, token_text in new_tokens)
+    ).ratio()
+
+    if similarity < 0.6: # return, the blocks are too different
+        for token_class, token_text in old_tokens:
+            old_tokens_result.append((token_class, '', token_text))
+        for token_class, token_text in new_tokens:
+            new_tokens_result.append((token_class, '', token_text))
+        return old_tokens_result, new_tokens_result, similarity
+
+    token_sequence_matcher = difflib.SequenceMatcher(None,
+        [x[1] for x in old_tokens],
+        [x[1] for x in new_tokens])
+
+    for tag, o1, o2, n1, n2 in token_sequence_matcher.get_opcodes():
+        # check the differences by token block types first to give a more
+        # nicer "block" level replacement vs character diffs
+
+        if tag == 'equal':
+            for token_class, token_text in old_tokens[o1:o2]:
+                old_tokens_result.append((token_class, '', token_text))
+            for token_class, token_text in new_tokens[n1:n2]:
+                new_tokens_result.append((token_class, '', token_text))
+        elif tag == 'delete':
+            for token_class, token_text in old_tokens[o1:o2]:
+                old_tokens_result.append((token_class, 'del', token_text))
+        elif tag == 'insert':
+            for token_class, token_text in new_tokens[n1:n2]:
+                new_tokens_result.append((token_class, 'ins', token_text))
+        elif tag == 'replace':
+            # if same type token blocks must be replaced, do a diff on the
+            # characters in the token blocks to show individual changes
+
+            old_char_tokens = []
+            new_char_tokens = []
+            for token_class, token_text in old_tokens[o1:o2]:
+                for char in token_text:
+                    old_char_tokens.append((token_class, char))
+
+            for token_class, token_text in new_tokens[n1:n2]:
+                for char in token_text:
+                    new_char_tokens.append((token_class, char))
+
+            old_string = ''.join([token_text for
+                token_class, token_text in old_char_tokens])
+            new_string = ''.join([token_text for
+                token_class, token_text in new_char_tokens])
+
+            char_sequence = difflib.SequenceMatcher(
+                None, old_string, new_string)
+            copcodes = char_sequence.get_opcodes()
+            obuffer, nbuffer = [], []
+
+            if use_diff_match_patch:
+                dmp = diff_match_patch()
+                dmp.Diff_EditCost = 11 # TODO: dan: extract this to a setting
+                reps = dmp.diff_main(old_string, new_string)
+                dmp.diff_cleanupEfficiency(reps)
+
+                a, b = 0, 0
+                for op, rep in reps:
+                    l = len(rep)
+                    if op == 0:
+                        for i, c in enumerate(rep):
+                            obuffer.append((old_char_tokens[a+i][0], '', c))
+                            nbuffer.append((new_char_tokens[b+i][0], '', c))
+                        a += l
+                        b += l
+                    elif op == -1:
+                        for i, c in enumerate(rep):
+                            obuffer.append((old_char_tokens[a+i][0], 'del', c))
+                        a += l
+                    elif op == 1:
+                        for i, c in enumerate(rep):
+                            nbuffer.append((new_char_tokens[b+i][0], 'ins', c))
+                        b += l
+            else:
+                for ctag, co1, co2, cn1, cn2 in copcodes:
+                    if ctag == 'equal':
+                        for token_class, token_text in old_char_tokens[co1:co2]:
+                            obuffer.append((token_class, '', token_text))
+                        for token_class, token_text in new_char_tokens[cn1:cn2]:
+                            nbuffer.append((token_class, '', token_text))
+                    elif ctag == 'delete':
+                        for token_class, token_text in old_char_tokens[co1:co2]:
+                            obuffer.append((token_class, 'del', token_text))
+                    elif ctag == 'insert':
+                        for token_class, token_text in new_char_tokens[cn1:cn2]:
+                            nbuffer.append((token_class, 'ins', token_text))
+                    elif ctag == 'replace':
+                        for token_class, token_text in old_char_tokens[co1:co2]:
+                            obuffer.append((token_class, 'del', token_text))
+                        for token_class, token_text in new_char_tokens[cn1:cn2]:
+                            nbuffer.append((token_class, 'ins', token_text))
+
+            old_tokens_result.extend(obuffer)
+            new_tokens_result.extend(nbuffer)
+
+    return old_tokens_result, new_tokens_result, similarity
+
+
+class DiffSet(object):
+    """
+    An object for parsing the diff result from diffs.DiffProcessor and
+    adding highlighting, side by side/unified renderings and line diffs
+    """
+
+    HL_REAL = 'REAL' # highlights using original file, slow
+    HL_FAST = 'FAST' # highlights using just the line, fast but not correct
+                     # in the case of multiline code
+    HL_NONE = 'NONE' # no highlighting, fastest
+
+    def __init__(self, highlight_mode=HL_REAL,
+                 source_node_getter=lambda filename: None,
+                 target_node_getter=lambda filename: None,
+                 source_nodes=None, target_nodes=None,
+                 max_file_size_limit=150 * 1024, # files over this size will
+                                                 # use fast highlighting
+                 ):
+
+        self.highlight_mode = highlight_mode
+        self.highlighted_filenodes = {}
+        self.source_node_getter = source_node_getter
+        self.target_node_getter = target_node_getter
+        self.source_nodes = source_nodes or {}
+        self.target_nodes = target_nodes or {}
+
+
+        self.max_file_size_limit = max_file_size_limit
+
+    def render_patchset(self, patchset, source_ref=None, target_ref=None):
+        diffset = AttributeDict(dict(
+            lines_added=0,
+            lines_deleted=0,
+            changed_files=0,
+            files=[],
+            limited_diff=isinstance(patchset, LimitedDiffContainer),
+            source_ref=source_ref,
+            target_ref=target_ref,
+        ))
+        for patch in patchset:
+            filediff = self.render_patch(patch)
+            filediff.diffset = diffset
+            diffset.files.append(filediff)
+            diffset.changed_files += 1
+            if not patch['stats']['binary']:
+                diffset.lines_added += patch['stats']['added']
+                diffset.lines_deleted += patch['stats']['deleted']
+
+        return diffset
+
+    _lexer_cache = {}
+    def _get_lexer_for_filename(self, filename):
+        # cached because we might need to call it twice for source/target
+        if filename not in self._lexer_cache:
+            self._lexer_cache[filename] = get_lexer_safe(filepath=filename)
+        return self._lexer_cache[filename]
+
+    def render_patch(self, patch):
+        log.debug('rendering diff for %r' % patch['filename'])
+
+        source_filename = patch['original_filename']
+        target_filename = patch['filename']
+
+        source_lexer = plain_text_lexer
+        target_lexer = plain_text_lexer
+
+        if not patch['stats']['binary']:
+            if self.highlight_mode == self.HL_REAL:
+                if (source_filename and patch['operation'] in ('D', 'M')
+                    and source_filename not in self.source_nodes):
+                        self.source_nodes[source_filename] = (
+                            self.source_node_getter(source_filename))
+
+                if (target_filename and patch['operation'] in ('A', 'M')
+                    and target_filename not in self.target_nodes):
+                        self.target_nodes[target_filename] = (
+                            self.target_node_getter(target_filename))
+
+            elif self.highlight_mode == self.HL_FAST:
+                source_lexer = self._get_lexer_for_filename(source_filename)
+                target_lexer = self._get_lexer_for_filename(target_filename)
+
+        source_file = self.source_nodes.get(source_filename, source_filename)
+        target_file = self.target_nodes.get(target_filename, target_filename)
+
+        source_filenode, target_filenode = None, None
+
+        # TODO: dan: FileNode.lexer works on the content of the file - which
+        # can be slow - issue #4289 explains a lexer clean up - which once
+        # done can allow caching a lexer for a filenode to avoid the file lookup
+        if isinstance(source_file, FileNode):
+            source_filenode = source_file
+            source_lexer = source_file.lexer
+        if isinstance(target_file, FileNode):
+            target_filenode = target_file
+            target_lexer = target_file.lexer
+
+        source_file_path, target_file_path = None, None
+
+        if source_filename != '/dev/null':
+            source_file_path = source_filename
+        if target_filename != '/dev/null':
+            target_file_path = target_filename
+
+        source_file_type = source_lexer.name
+        target_file_type = target_lexer.name
+
+        op_hunks = patch['chunks'][0]
+        hunks = patch['chunks'][1:]
+
+        filediff = AttributeDict({
+            'source_file_path': source_file_path,
+            'target_file_path': target_file_path,
+            'source_filenode': source_filenode,
+            'target_filenode': target_filenode,
+            'hunks': [],
+            'source_file_type': target_file_type,
+            'target_file_type': source_file_type,
+            'patch': patch,
+            'source_mode': patch['stats']['old_mode'],
+            'target_mode': patch['stats']['new_mode'],
+            'limited_diff': isinstance(patch, LimitedDiffContainer),
+            'diffset': self,
+        })
+
+        for hunk in hunks:
+            hunkbit = self.parse_hunk(hunk, source_file, target_file)
+            hunkbit.filediff = filediff
+            filediff.hunks.append(hunkbit)
+        return filediff
+
+    def parse_hunk(self, hunk, source_file, target_file):
+        result = AttributeDict(dict(
+            source_start=hunk['source_start'],
+            source_length=hunk['source_length'],
+            target_start=hunk['target_start'],
+            target_length=hunk['target_length'],
+            section_header=hunk['section_header'],
+            lines=[],
+        ))
+        before, after = [], []
+
+        for line in hunk['lines']:
+            if line['action'] == 'unmod':
+                result.lines.extend(
+                    self.parse_lines(before, after, source_file, target_file))
+                after.append(line)
+                before.append(line)
+            elif line['action'] == 'add':
+                after.append(line)
+            elif line['action'] == 'del':
+                before.append(line)
+            elif line['action'] == 'context-old':
+                before.append(line)
+            elif line['action'] == 'context-new':
+                after.append(line)
+
+        result.lines.extend(
+            self.parse_lines(before, after, source_file, target_file))
+        result.unified = self.as_unified(result.lines)
+        result.sideside = result.lines
+        return result
+
+    def parse_lines(self, before_lines, after_lines, source_file, target_file):
+        # TODO: dan: investigate doing the diff comparison and fast highlighting
+        # on the entire before and after buffered block lines rather than by
+        # line, this means we can get better 'fast' highlighting if the context
+        # allows it - eg.
+        # line 4: """
+        # line 5: this gets highlighted as a string
+        # line 6: """
+
+        lines = []
+        while before_lines or after_lines:
+            before, after = None, None
+            before_tokens, after_tokens = None, None
+
+            if before_lines:
+                before = before_lines.pop(0)
+            if after_lines:
+                after = after_lines.pop(0)
+
+            original = AttributeDict()
+            modified = AttributeDict()
+
+            if before:
+                before_tokens = self.get_line_tokens(
+                    line_text=before['line'], line_number=before['old_lineno'],
+                    file=source_file)
+                original.lineno = before['old_lineno']
+                original.content = before['line']
+                original.action = self.action_to_op(before['action'])
+
+            if after:
+                after_tokens = self.get_line_tokens(
+                    line_text=after['line'], line_number=after['new_lineno'],
+                    file=target_file)
+                modified.lineno = after['new_lineno']
+                modified.content = after['line']
+                modified.action = self.action_to_op(after['action'])
+
+
+            # diff the lines
+            if before_tokens and after_tokens:
+                o_tokens, m_tokens, similarity = tokens_diff(before_tokens, after_tokens)
+                original.content = render_tokenstream(o_tokens)
+                modified.content = render_tokenstream(m_tokens)
+            elif before_tokens:
+                original.content = render_tokenstream(
+                    [(x[0], '', x[1]) for x in before_tokens])
+            elif after_tokens:
+                modified.content = render_tokenstream(
+                    [(x[0], '', x[1]) for x in after_tokens])
+
+            lines.append(AttributeDict({
+                'original': original,
+                'modified': modified,
+            }))
+
+        return lines
+
+    def get_line_tokens(self, line_text, line_number, file=None):
+        filenode = None
+        filename = None
+
+        if isinstance(file, basestring):
+            filename = file
+        elif isinstance(file, FileNode):
+            filenode = file
+            filename = file.unicode_path
+
+        if self.highlight_mode == self.HL_REAL and filenode:
+            if line_number and file.size < self.max_file_size_limit:
+                return self.get_tokenized_filenode_line(file, line_number)
+
+        if self.highlight_mode in (self.HL_REAL, self.HL_FAST) and filename:
+            lexer = self._get_lexer_for_filename(filename)
+            return list(tokenize_string(line_text, lexer))
+
+        return list(tokenize_string(line_text, plain_text_lexer))
+
+    def get_tokenized_filenode_line(self, filenode, line_number):
+
+        if filenode not in self.highlighted_filenodes:
+            tokenized_lines = filenode_as_lines_tokens(filenode, filenode.lexer)
+            self.highlighted_filenodes[filenode] = tokenized_lines
+        return self.highlighted_filenodes[filenode][line_number - 1]
+
+    def action_to_op(self, action):
+        return {
+            'add': '+',
+            'del': '-',
+            'unmod': ' ',
+            'context-old': ' ',
+            'context-new': ' ',
+        }.get(action, action)
+
+    def as_unified(self, lines):
+        """ Return a generator that yields the lines of a diff in unified order """
+        def generator():
+            buf = []
+            for line in lines:
+
+                if buf and not line.original or line.original.action == ' ':
+                    for b in buf:
+                        yield b
+                    buf = []
+
+                if line.original:
+                    if line.original.action == ' ':
+                        yield (line.original.lineno, line.modified.lineno,
+                               line.original.action, line.original.content)
+                        continue
+
+                    if line.original.action == '-':
+                        yield (line.original.lineno, None,
+                               line.original.action, line.original.content)
+
+                    if line.modified.action == '+':
+                        buf.append((
+                            None, line.modified.lineno,
+                            line.modified.action, line.modified.content))
+                        continue
+
+                if line.modified:
+                    yield (None, line.modified.lineno,
+                           line.modified.action, line.modified.content)
+
+            for b in buf:
+                yield b
+
+        return generator()

rhodecode/lib/diffs.py

@@ -180,6 +180,8 b' class Action(object):'
     UNMODIFIED = 'unmod'
 
     CONTEXT = 'context'
+    CONTEXT_OLD = 'context-old'
+    CONTEXT_NEW = 'context-new'
 
 
 class DiffProcessor(object):
@@ -227,7 +229,7 b' class DiffProcessor(object):'
             self._parser = self._parse_gitdiff
         else:
             self.differ = self._highlight_line_udiff
-            self._parser = self._parse_udiff
+            self._parser = self._new_parse_gitdiff
 
     def _copy_iterator(self):
         """
@@ -491,9 +493,181 b' class DiffProcessor(object):'
 
         return diff_container(sorted(_files, key=sorter))
 
-    def _parse_udiff(self, inline_diff=True):
-        raise NotImplementedError()
+
+    # FIXME: NEWDIFFS: dan: this replaces the old _escaper function
+    def _process_line(self, string):
+        """
+        Process a diff line, checks the diff limit
+
+        :param string:
+        """
+
+        self.cur_diff_size += len(string)
+
+        if not self.show_full_diff and (self.cur_diff_size > self.diff_limit):
+            raise DiffLimitExceeded('Diff Limit Exceeded')
+
+        return safe_unicode(string)
+
+    # FIXME: NEWDIFFS: dan: this replaces _parse_gitdiff
+    def _new_parse_gitdiff(self, inline_diff=True):
+        _files = []
+        diff_container = lambda arg: arg
+        for chunk in self._diff.chunks():
+            head = chunk.header
+            log.debug('parsing diff %r' % head)
+
+            diff = imap(self._process_line, chunk.diff.splitlines(1))
+            raw_diff = chunk.raw
+            limited_diff = False
+            exceeds_limit = False
+            # if 'empty_file_to_modify_and_rename' in head['a_path']:
+            #     1/0
+            op = None
+            stats = {
+                'added': 0,
+                'deleted': 0,
+                'binary': False,
+                'old_mode': None,
+                'new_mode': None,
+                'ops': {},
+            }
+            if head['old_mode']:
+                stats['old_mode'] = head['old_mode']
+            if head['new_mode']:
+                stats['new_mode'] = head['new_mode']
+            if head['b_mode']:
+                stats['new_mode'] = head['b_mode']
+
+            if head['deleted_file_mode']:
+                op = OPS.DEL
+                stats['binary'] = True
+                stats['ops'][DEL_FILENODE] = 'deleted file'
+
+            elif head['new_file_mode']:
+                op = OPS.ADD
+                stats['binary'] = True
+                stats['old_mode'] = None
+                stats['new_mode'] = head['new_file_mode']
+                stats['ops'][NEW_FILENODE] = 'new file %s' % head['new_file_mode']
+            else:  # modify operation, can be copy, rename or chmod
+
+                # CHMOD
+                if head['new_mode'] and head['old_mode']:
+                    op = OPS.MOD
+                    stats['binary'] = True
+                    stats['ops'][CHMOD_FILENODE] = (
+                        'modified file chmod %s => %s' % (
+                            head['old_mode'], head['new_mode']))
+
+                # RENAME
+                if head['rename_from'] != head['rename_to']:
+                    op = OPS.MOD
+                    stats['binary'] = True
+                    stats['renamed'] = (head['rename_from'], head['rename_to'])
+                    stats['ops'][RENAMED_FILENODE] = (
+                        'file renamed from %s to %s' % (
+                            head['rename_from'], head['rename_to']))
+                # COPY
+                if head.get('copy_from') and head.get('copy_to'):
+                    op = OPS.MOD
+                    stats['binary'] = True
+                    stats['copied'] = (head['copy_from'], head['copy_to'])
+                    stats['ops'][COPIED_FILENODE] = (
+                        'file copied from %s to %s' % (
+                            head['copy_from'], head['copy_to']))
 
+                # If our new parsed headers didn't match anything fallback to
+                # old style detection
+                if op is None:
+                    if not head['a_file'] and head['b_file']:
+                        op = OPS.ADD
+                        stats['binary'] = True
+                        stats['new_file'] = True
+                        stats['ops'][NEW_FILENODE] = 'new file'
+
+                    elif head['a_file'] and not head['b_file']:
+                        op = OPS.DEL
+                        stats['binary'] = True
+                        stats['ops'][DEL_FILENODE] = 'deleted file'
+
+                # it's not ADD not DELETE
+                if op is None:
+                    op = OPS.MOD
+                    stats['binary'] = True
+                    stats['ops'][MOD_FILENODE] = 'modified file'
+
+            # a real non-binary diff
+            if head['a_file'] or head['b_file']:
+                try:
+                    raw_diff, chunks, _stats = self._new_parse_lines(diff)
+                    stats['binary'] = False
+                    stats['added'] = _stats[0]
+                    stats['deleted'] = _stats[1]
+                    # explicit mark that it's a modified file
+                    if op == OPS.MOD:
+                        stats['ops'][MOD_FILENODE] = 'modified file'
+                    exceeds_limit = len(raw_diff) > self.file_limit
+
+                    # changed from _escaper function so we validate size of
+                    # each file instead of the whole diff
+                    # diff will hide big files but still show small ones
+                    # from my tests, big files are fairly safe to be parsed
+                    # but the browser is the bottleneck
+                    if not self.show_full_diff and exceeds_limit:
+                        raise DiffLimitExceeded('File Limit Exceeded')
+
+                except DiffLimitExceeded:
+                    diff_container = lambda _diff: \
+                        LimitedDiffContainer(
+                            self.diff_limit, self.cur_diff_size, _diff)
+
+                    exceeds_limit = len(raw_diff) > self.file_limit
+                    limited_diff = True
+                    chunks = []
+
+            else:  # GIT format binary patch, or possibly empty diff
+                if head['bin_patch']:
+                    # we have operation already extracted, but we mark simply
+                    # it's a diff we wont show for binary files
+                    stats['ops'][BIN_FILENODE] = 'binary diff hidden'
+                chunks = []
+
+            if chunks and not self.show_full_diff and op == OPS.DEL:
+                # if not full diff mode show deleted file contents
+                # TODO: anderson: if the view is not too big, there is no way
+                # to see the content of the file
+                chunks = []
+
+            chunks.insert(0, [{
+                                  'old_lineno': '',
+                                  'new_lineno': '',
+                                  'action': Action.CONTEXT,
+                                  'line': msg,
+                              } for _op, msg in stats['ops'].iteritems()
+                              if _op not in [MOD_FILENODE]])
+
+            original_filename = safe_unicode(head['a_path'])
+            _files.append({
+                'original_filename': original_filename,
+                'filename': safe_unicode(head['b_path']),
+                'old_revision': head['a_blob_id'],
+                'new_revision': head['b_blob_id'],
+                'chunks': chunks,
+                'raw_diff': safe_unicode(raw_diff),
+                'operation': op,
+                'stats': stats,
+                'exceeds_limit': exceeds_limit,
+                'is_limited_diff': limited_diff,
+            })
+
+
+        sorter = lambda info: {OPS.ADD: 0, OPS.MOD: 1,
+                               OPS.DEL: 2}.get(info['operation'])
+
+        return diff_container(sorted(_files, key=sorter))
+
+    # FIXME: NEWDIFFS: dan: this gets replaced by _new_parse_lines
     def _parse_lines(self, diff):
         """
         Parse the diff an return data for the template.
@@ -588,6 +762,107 b' class DiffProcessor(object):'
             pass
         return ''.join(raw_diff), chunks, stats
 
+    # FIXME: NEWDIFFS: dan: this replaces _parse_lines
+    def _new_parse_lines(self, diff):
+        """
+        Parse the diff an return data for the template.
+        """
+
+        lineiter = iter(diff)
+        stats = [0, 0]
+        chunks = []
+        raw_diff = []
+
+        try:
+            line = lineiter.next()
+
+            while line:
+                raw_diff.append(line)
+                match = self._chunk_re.match(line)
+
+                if not match:
+                    break
+
+                gr = match.groups()
+                (old_line, old_end,
+                 new_line, new_end) = [int(x or 1) for x in gr[:-1]]
+
+                lines = []
+                hunk = {
+                    'section_header': gr[-1],
+                    'source_start': old_line,
+                    'source_length': old_end,
+                    'target_start': new_line,
+                    'target_length': new_end,
+                    'lines': lines,
+                }
+                chunks.append(hunk)
+
+                old_line -= 1
+                new_line -= 1
+
+                context = len(gr) == 5
+                old_end += old_line
+                new_end += new_line
+
+                line = lineiter.next()
+
+                while old_line < old_end or new_line < new_end:
+                    command = ' '
+                    if line:
+                        command = line[0]
+
+                    affects_old = affects_new = False
+
+                    # ignore those if we don't expect them
+                    if command in '#@':
+                        continue
+                    elif command == '+':
+                        affects_new = True
+                        action = Action.ADD
+                        stats[0] += 1
+                    elif command == '-':
+                        affects_old = True
+                        action = Action.DELETE
+                        stats[1] += 1
+                    else:
+                        affects_old = affects_new = True
+                        action = Action.UNMODIFIED
+
+                    if not self._newline_marker.match(line):
+                        old_line += affects_old
+                        new_line += affects_new
+                        lines.append({
+                            'old_lineno':   affects_old and old_line or '',
+                            'new_lineno':   affects_new and new_line or '',
+                            'action':       action,
+                            'line':         self._clean_line(line, command)
+                        })
+                        raw_diff.append(line)
+
+                    line = lineiter.next()
+
+                    if self._newline_marker.match(line):
+                        # we need to append to lines, since this is not
+                        # counted in the line specs of diff
+                        if affects_old:
+                            action = Action.CONTEXT_OLD
+                        elif affects_new:
+                            action = Action.CONTEXT_NEW
+                        else:
+                            raise Exception('invalid context for no newline')
+
+                        lines.append({
+                            'old_lineno':   None,
+                            'new_lineno':   None,
+                            'action':       action,
+                            'line':         self._clean_line(line, command)
+                        })
+
+        except StopIteration:
+            pass
+        return ''.join(raw_diff), chunks, stats
+
     def _safe_id(self, idstring):
         """Make a string safe for including in an id attribute.
 

rhodecode/lib/vcs/backends/git/diff.py

@@ -32,11 +32,13 b' class GitDiff(base.Diff):'
     _header_re = re.compile(r"""
         #^diff[ ]--git
             [ ]"?a/(?P<a_path>.+?)"?[ ]"?b/(?P<b_path>.+?)"?\n
-        (?:^similarity[ ]index[ ](?P<similarity_index>\d+)%\n
-           ^rename[ ]from[ ](?P<rename_from>[^\r\n]+)\n
-           ^rename[ ]to[ ](?P<rename_to>[^\r\n]+)(?:\n|$))?
         (?:^old[ ]mode[ ](?P<old_mode>\d+)\n
            ^new[ ]mode[ ](?P<new_mode>\d+)(?:\n|$))?
+        (?:^similarity[ ]index[ ](?P<similarity_index>\d+)%(?:\n|$))?
+        (?:^rename[ ]from[ ](?P<rename_from>[^\r\n]+)\n
+           ^rename[ ]to[ ](?P<rename_to>[^\r\n]+)(?:\n|$))?
+        (?:^copy[ ]from[ ](?P<copy_from>[^\r\n]+)\n
+           ^copy[ ]to[ ](?P<copy_to>[^\r\n]+)(?:\n|$))?
         (?:^new[ ]file[ ]mode[ ](?P<new_file_mode>.+)(?:\n|$))?
         (?:^deleted[ ]file[ ]mode[ ](?P<deleted_file_mode>.+)(?:\n|$))?
         (?:^index[ ](?P<a_blob_id>[0-9A-Fa-f]+)

rhodecode/public/css/buttons.less

@@ -188,6 +188,14 b' input[type="button"] {'
     padding: @padding * 1.2;
 }
 
+.btn-group {
+    display: inline-block;
+    .btn {
+        float: left;
+        margin: 0 0 0 -1px;
+    }
+}
+
 .btn-link {
     background: transparent;
     border: none;
@@ -326,15 +334,15 b' input[type="submit"],'
 input[type="reset"] {
     &.btn-danger {
         &:extend(.btn-danger);
-    
+
         &:focus {
             outline: 0;
         }
-    
+
         &:hover {
             &:extend(.btn-danger:hover);
         }
-    
+
         &.btn-link {
             &:extend(.btn-link);
             color: @alert2;

rhodecode/public/css/code-block.less

@@ -646,14 +646,210 b' pre.literal-block, .codehilite pre{'
 
 @cb-line-height: 18px;
 @cb-line-code-padding: 10px;
+@cb-text-padding: 5px;
 
+@diff-pill-padding: 2px 7px;
+
+input.diff-collapse-state {
+    display: none;
+
+    &:checked + .diff { /* file diff is collapsed */
+        .cb {
+            display: none
+        }
+        .diff-collapse-indicator {
+            border-width: 9px 0 9px 15.6px;
+            border-color: transparent transparent transparent #ccc;
+        }
+        .diff-menu {
+            display: none;
+        }
+        margin: -1px 0 0 0;
+    }
+
+    &+ .diff { /* file diff is expanded */
+        .diff-collapse-indicator {
+            border-width: 15.6px 9px 0 9px;
+            border-color: #ccc transparent transparent transparent;
+        }
+        .diff-menu {
+            display: block;
+        }
+        margin: 20px 0;
+    }
+}
+.diff {
+    border: 1px solid @grey5;
+
+    /* START OVERRIDES */
+    .code-highlight {
+        border: none;  // TODO: remove this border from the global
+                       // .code-highlight, it doesn't belong there
+    }
+    label {
+        margin: 0; // TODO: remove this margin definition from global label
+                   // it doesn't belong there - if margin on labels
+                   // are needed for a form they should be defined
+                   // in the form's class
+    }
+    /* END OVERRIDES */
+
+    * {
+        box-sizing: border-box;
+    }
+    .diff-anchor {
+        visibility: hidden;
+    }
+    &:hover {
+        .diff-anchor {
+            visibility: visible;
+        }
+    }
+
+    .diff-collapse-indicator {
+        width: 0;
+        height: 0;
+        border-style: solid;
+        float: left;
+        margin: 2px 2px 0 0;
+        cursor: pointer;
+    }
+
+    .diff-heading {
+        background: @grey7;
+        cursor: pointer;
+        display: block;
+        padding: 5px 10px;
+    }
+    .diff-heading:after {
+        content: "";
+        display: table;
+        clear: both;
+    }
+    .diff-heading:hover {
+        background: #e1e9f4 !important;
+    }
+
+    .diff-menu {
+        float: right;
+        a, button {
+            padding: 5px;
+            display: block;
+            float: left
+        }
+    }
+    .diff-pill {
+        display: block;
+        float: left;
+        padding: @diff-pill-padding;
+    }
+    .diff-pill-group {
+        .diff-pill {
+            opacity: .8;
+            &:first-child {
+                border-radius: @border-radius 0 0 @border-radius;
+            }
+            &:last-child {
+                border-radius: 0 @border-radius @border-radius 0;
+            }
+            &:only-child {
+                border-radius: @border-radius;
+            }
+        }
+    }
+    .diff-pill {
+        &[op="name"] {
+            background: none;
+            color: @grey2;
+            opacity: 1;
+            color: white;
+        }
+        &[op="limited"] {
+            background: @grey2;
+            color: white;
+        }
+        &[op="binary"] {
+            background: @color7;
+            color: white;
+        }
+        &[op="modified"] {
+            background: @alert1;
+            color: white;
+        }
+        &[op="renamed"] {
+            background: @color4;
+            color: white;
+        }
+        &[op="mode"] {
+            background: @grey3;
+            color: white;
+        }
+        &[op="symlink"] {
+            background: @color8;
+            color: white;
+        }
+
+        &[op="added"] { /* added lines */
+            background: @alert1;
+            color: white;
+        }
+        &[op="deleted"] { /* deleted lines */
+            background: @alert2;
+            color: white;
+        }
+
+        &[op="created"] { /* created file */
+            background: @alert1;
+            color: white;
+        }
+        &[op="removed"] { /* deleted file */
+            background: @color5;
+            color: white;
+        }
+    }
+
+    .diff-collapse-button, .diff-expand-button {
+        cursor: pointer;
+    }
+    .diff-collapse-button {
+        display: inline;
+    }
+    .diff-expand-button {
+        display: none;
+    }
+    .diff-collapsed .diff-collapse-button {
+        display: none;
+    }
+    .diff-collapsed .diff-expand-button {
+        display: inline;
+    }
+}
 table.cb {
     width: 100%;
     border-collapse: collapse;
-    margin-bottom: 10px;
 
-    * {
-        box-sizing: border-box;
+    .cb-text {
+        padding: @cb-text-padding;
+    }
+    .cb-hunk {
+        padding: @cb-text-padding;
+    }
+    .cb-expand {
+        display: none;
+    }
+    .cb-collapse {
+        display: inline;
+    }
+    &.cb-collapsed {
+        .cb-line {
+            display: none;
+        }
+        .cb-expand {
+            display: inline;
+        }
+        .cb-collapse {
+            display: none;
+        }
     }
 
     /* intentionally general selector since .cb-line-selected must override it
@@ -663,18 +859,45 b' table.cb {'
     .cb-line-fresh .cb-content {
         background: white !important;
     }
+    .cb-warning {
+        background: #fff4dd;
+    }
 
-    tr.cb-annotate {
-        border-top: 1px solid #eee;
+    &.cb-diff-sideside {
+        td {
+            &.cb-content {
+                width: 50%;
+            }
+        }
+    }
 
-        &+ .cb-line {
+    tr {
+        &.cb-annotate {
             border-top: 1px solid #eee;
+
+            &+ .cb-line {
+                border-top: 1px solid #eee;
+            }
+
+            &:first-child {
+                border-top: none;
+                &+ .cb-line {
+                    border-top: none;
+                }
+            }
         }
 
-        &:first-child {
-            border-top: none;
-            &+ .cb-line {
-                border-top: none;
+        &.cb-hunk {
+            font-family: @font-family-monospace;
+            color: rgba(0, 0, 0, 0.3);
+
+            td {
+                &:first-child {
+                    background: #edf2f9;
+                }
+                &:last-child {
+                    background: #f4f7fb;
+                }
             }
         }
     }
@@ -686,9 +909,14 b' table.cb {'
         &.cb-content {
             font-size: 12.35px;
 
+            &.cb-line-selected .cb-code {
+                background: @comment-highlight-color !important;
+            }
+
             span.cb-code {
                 line-height: @cb-line-height;
                 padding-left: @cb-line-code-padding;
+                padding-right: @cb-line-code-padding;
                 display: block;
                 white-space: pre-wrap;
                 font-family: @font-family-monospace;
@@ -714,14 +942,38 b' table.cb {'
             a {
                 display: block;
                 padding-right: @cb-line-code-padding;
+                padding-left: @cb-line-code-padding;
                 line-height: @cb-line-height;
                 color: rgba(0, 0, 0, 0.3);
             }
         }
 
-        &.cb-content {
-            &.cb-line-selected .cb-code {
-                background: @comment-highlight-color !important;
+        &.cb-empty {
+            background: @grey7;
+        }
+
+        ins {
+            color: black;
+            background: #a6f3a6;
+            text-decoration: none;
+        }
+        del {
+            color: black;
+            background: #f8cbcb;
+            text-decoration: none;
+        }
+        &.cb-addition {
+            background: #ecffec;
+
+            &.blob-lineno {
+                background: #ddffdd;
+            }
+        }
+        &.cb-deletion {
+            background: #ffecec;
+
+            &.blob-lineno {
+                background: #ffdddd;
             }
         }
 

rhodecode/public/js/src/rhodecode.js

@@ -221,14 +221,32 b' var formatSelect2SelectionRefs = functio'
 };
 
 // takes a given html element and scrolls it down offset pixels
-function offsetScroll(element, offset){
-    setTimeout(function(){
+function offsetScroll(element, offset) {
+    setTimeout(function() {
         var location = element.offset().top;
         // some browsers use body, some use html
         $('html, body').animate({ scrollTop: (location - offset) });
     }, 100);
 }
 
+// scroll an element `percent`% from the top of page in `time` ms
+function scrollToElement(element, percent, time) {
+    percent = (percent === undefined ? 25 : percent);
+    time = (time === undefined ? 100 : time);
+
+    var $element = $(element);
+    var elOffset = $element.offset().top;
+    var elHeight = $element.height();
+    var windowHeight = $(window).height();
+    var offset = elOffset;
+    if (elHeight < windowHeight) {
+        offset = elOffset - ((windowHeight / (100 / percent)) - (elHeight / 2));
+    }
+    setTimeout(function() {
+        $('html, body').animate({ scrollTop: offset});
+    }, time);
+}
+
 /**
  * global hooks after DOM is loaded
  */
@@ -418,6 +436,10 b' function offsetScroll(element, offset){'
         var result = splitDelimitedHash(location.hash);
         var loc  = result.loc;
         if (loc.length > 1) {
+
+            var highlightable_line_tds = [];
+
+            // source code line format
             var page_highlights = loc.substring(
                 loc.indexOf('#') + 1).split('L');
 
@@ -442,33 +464,27 b' function offsetScroll(element, offset){'
                 for (pos in h_lines) {
                     var line_td = $('td.cb-lineno#L' + h_lines[pos]);
                     if (line_td.length) {
-                        line_td.addClass('cb-line-selected'); // line number td
-                        line_td.next().addClass('cb-line-selected'); // line content
+                        highlightable_line_tds.push(line_td);
                     }
                 }
-                var first_line_td = $('td.cb-lineno#L' + h_lines[0]);
-                if (first_line_td.length) {
-                    var elOffset = first_line_td.offset().top;
-                    var elHeight = first_line_td.height();
-                    var windowHeight = $(window).height();
-                    var offset;
+            }
 
-                    if (elHeight < windowHeight) {
-                        offset = elOffset - ((windowHeight / 4) - (elHeight / 2));
-                    }
-                    else {
-                        offset = elOffset;
-                    }
-                    $(function() { // let browser scroll to hash first, then
-                                   // scroll the line to the middle of page
-                        setTimeout(function() {
-                            $('html, body').animate({ scrollTop: offset });
-                          }, 100);
-                    });
-                    $.Topic('/ui/plugins/code/anchor_focus').prepareOrPublish({
-                        lineno: first_line_td,
-                        remainder: result.remainder});
-                }
+            // now check a direct id reference (diff page)
+            if ($(loc).length && $(loc).hasClass('cb-lineno')) {
+                highlightable_line_tds.push($(loc));
+            }
+            $.each(highlightable_line_tds, function (i, $td) {
+                $td.addClass('cb-line-selected'); // line number td
+                $td.next().addClass('cb-line-selected'); // line content
+            });
+
+            if (highlightable_line_tds.length) {
+                var $first_line_td = highlightable_line_tds[0];
+                scrollToElement($first_line_td);
+                $.Topic('/ui/plugins/code/anchor_focus').prepareOrPublish({
+                    lineno: $first_line_td,
+                    remainder: result.remainder
+                });
             }
         }
     }

rhodecode/templates/compare/compare_diff.html

@@ -1,5 +1,6 b''
 ## -*- coding: utf-8 -*-
 <%inherit file="/base/base.html"/>
+<%namespace name="cbdiffs" file="/codeblocks/diffs.html"/>
 
 <%def name="title()">
     %if c.compare_home:
@@ -53,7 +54,7 b''
                                     <a id="btn-swap" class="btn btn-primary" href="${c.swap_url}"><i class="icon-refresh"></i> ${_('Swap')}</a>
                                 %endif
                                 <div id="compare_revs" class="btn btn-primary"><i class ="icon-loop"></i> ${_('Compare Commits')}</div>
-                                %if c.files:
+                                %if c.diffset and c.diffset.files:
                                     <div id="compare_changeset_status_toggle" class="btn btn-primary">${_('Comment')}</div>
                                 %endif
                             </div>
@@ -248,72 +249,7 b''
                 <div id="changeset_compare_view_content">
                     ##CS
                     <%include file="compare_commits.html"/>
-
-                    ## FILES
-                  <div class="cs_files_title">
-                    <span class="cs_files_expand">
-                        <span id="expand_all_files">${_('Expand All')}</span> | <span id="collapse_all_files">${_('Collapse All')}</span>
-                    </span>
-                    <h2>
-                        ${diff_block.diff_summary_text(len(c.files), c.lines_added, c.lines_deleted, c.limited_diff)}
-                    </h2>
-                  </div>
-                    <div class="cs_files">
-                      %if not c.files:
-                         <p class="empty_data">${_('No files')}</p>
-                      %endif
-                  <table class="compare_view_files">
-                  <%namespace name="diff_block" file="/changeset/diff_block.html"/>
-                    %for FID, change, path, stats, file in c.files:
-                    <tr class="cs_${change} collapse_file" fid="${FID}">
-                        <td class="cs_icon_td">
-                            <span class="collapse_file_icon" fid="${FID}"></span>
-                        </td>
-                        <td class="cs_icon_td">
-                            <div class="flag_status not_reviewed hidden"></div>
-                        </td>
-                        <td class="cs_${change}" id="a_${FID}">
-                            <div class="node">
-                                <a href="#a_${FID}">
-                                    <i class="icon-file-${change.lower()}"></i>
-                                    ${h.safe_unicode(path)}
-                                </a>
-                            </div>
-                        </td>
-                        <td>
-                            <div class="changes pull-right">${h.fancy_file_stats(stats)}</div>
-                            <div class="comment-bubble pull-right" data-path="${path}">
-                              <i class="icon-comment"></i>
-                            </div>
-                        </td>
-                    </tr>
-                    <tr fid="${FID}" id="diff_${FID}" class="diff_links">
-                        <td></td>
-                        <td></td>
-                        <td class="cs_${change}">
-                            %if c.target_repo.repo_name == c.repo_name:
-                                ${diff_block.diff_menu(c.repo_name, h.safe_unicode(path), c.source_ref, c.target_ref, change, file)}
-                            %else:
-                                ## this is slightly different case later, since the target repo can have this
-                                ## file in target state than the source repo
-                                ${diff_block.diff_menu(c.target_repo.repo_name, h.safe_unicode(path), c.source_ref, c.target_ref, change, file)}
-                            %endif
-                        </td>
-                        <td class="td-actions rc-form">
-                        </td>
-                    </tr>
-                    <tr id="tr_${FID}">
-                      <td></td>
-                      <td></td>
-                      <td class="injected_diff" colspan="2">
-                          ${diff_block.diff_block_simple([c.changes[FID]])}
-                      </td>
-                    </tr>
-                  %endfor
-                  </table>
-                    % if c.limited_diff:
-                        ${diff_block.changeset_message()}
-                    % endif
+                    ${cbdiffs.render_diffset(c.diffset)}
                  </div>
             %endif
         </div>

rhodecode/tests/functional/test_changeset.py

@@ -104,7 +104,7 b' class TestChangesetController(object):'
 
         response.mustcontain(_shorten_commit_id(commit_ids[0]))
         response.mustcontain(_shorten_commit_id(commit_ids[1]))
-        
+
         # svn is special
         if backend.alias == 'svn':
             response.mustcontain('new file 10644')
@@ -146,7 +146,7 b' class TestChangesetController(object):'
         # files op files
         response.mustcontain('File no longer present at commit: %s' %
                              _shorten_commit_id(commit_ids[1]))
-        
+
         # svn is special
         if backend.alias == 'svn':
             response.mustcontain('new file 10644')
@@ -158,7 +158,7 b' class TestChangesetController(object):'
         response.mustcontain('Added docstrings to vcs.cli')  # commit msg
         response.mustcontain('Changed theme to ADC theme')  # commit msg
 
-        self._check_diff_menus(response)
+        self._check_new_diff_menus(response)
 
     def test_changeset_range(self, backend):
         self._check_changeset_range(
@@ -273,7 +273,7 b' Added a symlink'
 """ + diffs['svn'],
     }
 
-    def _check_diff_menus(self, response, right_menu=False):
+    def _check_diff_menus(self, response, right_menu=False,):
         # diff menus
         for elem in ['Show File', 'Unified Diff', 'Side-by-side Diff',
                      'Raw Diff', 'Download Diff']:
@@ -284,3 +284,16 b' Added a symlink'
             for elem in ['Ignore whitespace', 'Increase context',
                          'Hide comments']:
                 response.mustcontain(elem)
+
+
+    def _check_new_diff_menus(self, response, right_menu=False,):
+        # diff menus
+        for elem in ['Show file before', 'Show file after',
+                     'Raw diff', 'Download diff']:
+            response.mustcontain(elem)
+
+        # right pane diff menus
+        if right_menu:
+            for elem in ['Ignore whitespace', 'Increase context',
+                         'Hide comments']:
+                response.mustcontain(elem)

rhodecode/tests/functional/test_compare.py

@@ -20,6 +20,7 b''
 
 import mock
 import pytest
+import lxml.html
 
 from rhodecode.lib.vcs.backends.base import EmptyCommit
 from rhodecode.lib.vcs.exceptions import RepositoryRequirementError
@@ -609,9 +610,12 b' class ComparePage(AssertResponse):'
     """
 
     def contains_file_links_and_anchors(self, files):
+        doc = lxml.html.fromstring(self.response.body)
         for filename, file_id in files:
-            self.contains_one_link(filename, '#' + file_id)
             self.contains_one_anchor(file_id)
+            diffblock = doc.cssselect('[data-f-path="%s"]' % filename)
+            assert len(diffblock) == 1
+            assert len(diffblock[0].cssselect('a[href="#%s"]' % file_id)) == 1
 
     def contains_change_summary(self, files_changed, inserted, deleted):
         template = (

rhodecode/tests/lib/test_codeblocks.py

@@ -264,19 +264,19 b' class TestRenderTokenStream(object):'
         ),
         (
             [('A', '', u'two\n'), ('A', '', u'lines')],
-            '<span class="A">two<nl>\n</nl>lines</span>',
+            '<span class="A">two\nlines</span>',
         ),
         (
             [('A', '', u'\nthree\n'), ('A', '', u'lines')],
-            '<span class="A"><nl>\n</nl>three<nl>\n</nl>lines</span>',
+            '<span class="A">\nthree\nlines</span>',
         ),
         (
             [('', '', u'\n'), ('A', '', u'line')],
-            '<span><nl>\n</nl></span><span class="A">line</span>',
+            '<span>\n</span><span class="A">line</span>',
         ),
         (
             [('', 'ins', u'\n'), ('A', '', u'line')],
-            '<span><ins><nl>\n</nl></ins></span><span class="A">line</span>',
+            '<span><ins>\n</ins></span><span class="A">line</span>',
         ),
         (
             [('A', '', u'hel'), ('A', 'ins', u'lo')],