fix speed regression in mdiff caused by line split bugfix.

mercurial/mdiff.py

@@ -1,210 +1,205 b''
 # mdiff.py - diff and patch routines for mercurial
 #
 # Copyright 2005 Matt Mackall <[e-mail]>
 #
 # This software may be used and distributed according to the terms
 # of the GNU General Public License, incorporated herein by reference.
 
 from demandload import demandload
 import struct, bdiff, util, mpatch
 demandload(globals(), "re")
 
-
-def splitnewlines(text, keepends=False):
+def splitnewlines(text):
     '''like str.splitlines, but only split on newlines.'''
-    i = 0
-    lines = []
-    while True:
-        n = text.find('\n', i)
-        if n == -1:
-            last = text[i:]
-            if last:
-                lines.append(last)
-            return lines
-        lines.append(text[i:keepends and n+1 or n])
-        i = n + 1
+    lines = [l + '\n' for l in text.split('\n')]
+    if lines:
+        if lines[-1] == '\n':
+            lines.pop()
+        else:
+            lines[-1] = lines[-1][:-1]
+    return lines
 
 def unidiff(a, ad, b, bd, fn, r=None, text=False,
             showfunc=False, ignorews=False):
 
     if not a and not b: return ""
     epoch = util.datestr((0, 0))
 
     if not text and (util.binary(a) or util.binary(b)):
         l = ['Binary file %s has changed\n' % fn]
     elif not a:
-        b = splitnewlines(b, keepends=True)
+        b = splitnewlines(b)
         if a is None:
             l1 = "--- %s\t%s\n" % ("/dev/null", epoch)
         else:
             l1 = "--- %s\t%s\n" % ("a/" + fn, ad)
         l2 = "+++ %s\t%s\n" % ("b/" + fn, bd)
         l3 = "@@ -0,0 +1,%d @@\n" % len(b)
         l = [l1, l2, l3] + ["+" + e for e in b]
     elif not b:
-        a = splitnewlines(a, keepends=True)
+        a = splitnewlines(a)
         l1 = "--- %s\t%s\n" % ("a/" + fn, ad)
         if b is None:
             l2 = "+++ %s\t%s\n" % ("/dev/null", epoch)
         else:
             l2 = "+++ %s\t%s\n" % ("b/" + fn, bd)
         l3 = "@@ -1,%d +0,0 @@\n" % len(a)
         l = [l1, l2, l3] + ["-" + e for e in a]
     else:
-        al = splitnewlines(a, keepends=True)
-        bl = splitnewlines(b, keepends=True)
+        al = splitnewlines(a)
+        bl = splitnewlines(b)
         l = list(bunidiff(a, b, al, bl, "a/" + fn, "b/" + fn,
                           showfunc=showfunc, ignorews=ignorews))
         if not l: return ""
         # difflib uses a space, rather than a tab
         l[0] = "%s\t%s\n" % (l[0][:-2], ad)
         l[1] = "%s\t%s\n" % (l[1][:-2], bd)
 
     for ln in xrange(len(l)):
         if l[ln][-1] != '\n':
             l[ln] += "\n\ No newline at end of file\n"
 
     if r:
         l.insert(0, "diff %s %s\n" %
                     (' '.join(["-r %s" % rev for rev in r]), fn))
 
     return "".join(l)
 
 # somewhat self contained replacement for difflib.unified_diff
 # t1 and t2 are the text to be diffed
 # l1 and l2 are the text broken up into lines
 # header1 and header2 are the filenames for the diff output
 # context is the number of context lines
 # showfunc enables diff -p output
 # ignorews ignores all whitespace changes in the diff
 def bunidiff(t1, t2, l1, l2, header1, header2, context=3, showfunc=False,
              ignorews=False):
     def contextend(l, len):
         ret = l + context
         if ret > len:
             ret = len
         return ret
 
     def contextstart(l):
         ret = l - context
         if ret < 0:
             return 0
         return ret
 
     def yieldhunk(hunk, header):
         if header:
             for x in header:
                 yield x
         (astart, a2, bstart, b2, delta) = hunk
         aend = contextend(a2, len(l1))
         alen = aend - astart
         blen = b2 - bstart + aend - a2
 
         func = ""
         if showfunc:
             # walk backwards from the start of the context
             # to find a line starting with an alphanumeric char.
             for x in xrange(astart, -1, -1):
                 t = l1[x].rstrip()
                 if funcre.match(t):
                     func = ' ' + t[:40]
                     break
 
         yield "@@ -%d,%d +%d,%d @@%s\n" % (astart + 1, alen,
                                            bstart + 1, blen, func)
         for x in delta:
             yield x
         for x in xrange(a2, aend):
             yield ' ' + l1[x]
 
     header = [ "--- %s\t\n" % header1, "+++ %s\t\n" % header2 ]
 
     if showfunc:
         funcre = re.compile('\w')
     if ignorews:
         wsre = re.compile('[ \t]')
 
     # bdiff.blocks gives us the matching sequences in the files.  The loop
     # below finds the spaces between those matching sequences and translates
     # them into diff output.
     #
     diff = bdiff.blocks(t1, t2)
     hunk = None
     for i in xrange(len(diff)):
         # The first match is special.
         # we've either found a match starting at line 0 or a match later
         # in the file.  If it starts later, old and new below will both be
         # empty and we'll continue to the next match.
         if i > 0:
             s = diff[i-1]
         else:
             s = [0, 0, 0, 0]
         delta = []
         s1 = diff[i]
         a1 = s[1]
         a2 = s1[0]
         b1 = s[3]
         b2 = s1[2]
 
         old = l1[a1:a2]
         new = l2[b1:b2]
 
         # bdiff sometimes gives huge matches past eof, this check eats them,
         # and deals with the special first match case described above
         if not old and not new:
             continue
 
         if ignorews:
             wsold = wsre.sub('', "".join(old))
             wsnew = wsre.sub('', "".join(new))
             if wsold == wsnew:
                 continue
 
         astart = contextstart(a1)
         bstart = contextstart(b1)
         prev = None
         if hunk:
             # join with the previous hunk if it falls inside the context
             if astart < hunk[1] + context + 1:
                 prev = hunk
                 astart = hunk[1]
                 bstart = hunk[3]
             else:
                 for x in yieldhunk(hunk, header):
                     yield x
                 # we only want to yield the header if the files differ, and
                 # we only want to yield it once.
                 header = None
         if prev:
             # we've joined the previous hunk, record the new ending points.
             hunk[1] = a2
             hunk[3] = b2
             delta = hunk[4]
         else:
             # create a new hunk
             hunk = [ astart, a2, bstart, b2, delta ]
 
         delta[len(delta):] = [ ' ' + x for x in l1[astart:a1] ]
         delta[len(delta):] = [ '-' + x for x in old ]
         delta[len(delta):] = [ '+' + x for x in new ]
 
     if hunk:
         for x in yieldhunk(hunk, header):
             yield x
 
 def patchtext(bin):
     pos = 0
     t = []
     while pos < len(bin):
         p1, p2, l = struct.unpack(">lll", bin[pos:pos + 12])
         pos += 12
         t.append(bin[pos:pos + l])
         pos += l
     return "".join(t)
 
 def patch(a, bin):
     return mpatch.patches(a, [bin])
 
 patches = mpatch.patches
 patchedsize = mpatch.patchedsize
 textdiff = bdiff.bdiff