graphlog: split the actual DAG grapher out into a separate method

This allows extensions like pbranch to use asciigraph() to graph dependencies
for patch branches, but could be used for basically any DAG.

hgext/graphlog.py

@@ -1,325 +1,349 b''
 # ASCII graph log extension for Mercurial
 #
 # Copyright 2007 Joel Rosdahl <[e-mail]>
 #
 # This software may be used and distributed according to the terms of
 # the GNU General Public License, incorporated herein by reference.
 '''show revision graphs in terminal windows'''
 
 import os
 import sys
 from mercurial.cmdutil import revrange, show_changeset
 from mercurial.commands import templateopts
 from mercurial.i18n import _
 from mercurial.node import nullrev
 from mercurial.util import Abort, canonpath
 from mercurial import util
 
 def revision_grapher(repo, start_rev, stop_rev):
     """incremental revision grapher
 
     This generator function walks through the revision history from
     revision start_rev to revision stop_rev (which must be less than
     or equal to start_rev) and for each revision emits tuples with the
     following elements:
 
       - Current revision.
       - Current node.
       - Column of the current node in the set of ongoing edges.
       - Edges; a list of (col, next_col) indicating the edges between
         the current node and its parents.
       - Number of columns (ongoing edges) in the current revision.
       - The difference between the number of columns (ongoing edges)
         in the next revision and the number of columns (ongoing edges)
         in the current revision. That is: -1 means one column removed;
         0 means no columns added or removed; 1 means one column added.
     """
 
     assert start_rev >= stop_rev
     curr_rev = start_rev
     revs = []
     while curr_rev >= stop_rev:
         node = repo.changelog.node(curr_rev)
 
         # Compute revs and next_revs.
         if curr_rev not in revs:
             # New head.
             revs.append(curr_rev)
         rev_index = revs.index(curr_rev)
         next_revs = revs[:]
 
         # Add parents to next_revs.
         parents = get_rev_parents(repo, curr_rev)
         parents_to_add = []
         for parent in parents:
             if parent not in next_revs:
                 parents_to_add.append(parent)
         next_revs[rev_index:rev_index + 1] = util.sort(parents_to_add)
 
         edges = []
         for parent in parents:
             edges.append((rev_index, next_revs.index(parent)))
 
         n_columns_diff = len(next_revs) - len(revs)
         yield (curr_rev, node, rev_index, edges, len(revs), n_columns_diff)
 
         revs = next_revs
         curr_rev -= 1
 
 def filelog_grapher(repo, path, start_rev, stop_rev):
     """incremental file log grapher
 
     This generator function walks through the revision history of a
     single file from revision start_rev to revision stop_rev (which must
     be less than or equal to start_rev) and for each revision emits
     tuples with the following elements:
 
       - Current revision.
       - Current node.
       - Column of the current node in the set of ongoing edges.
       - Edges; a list of (col, next_col) indicating the edges between
         the current node and its parents.
       - Number of columns (ongoing edges) in the current revision.
       - The difference between the number of columns (ongoing edges)
         in the next revision and the number of columns (ongoing edges)
         in the current revision. That is: -1 means one column removed;
         0 means no columns added or removed; 1 means one column added.
     """
 
     assert start_rev >= stop_rev
     revs = []
     filerev = len(repo.file(path)) - 1
     while filerev >= 0:
         fctx = repo.filectx(path, fileid=filerev)
 
         # Compute revs and next_revs.
         if filerev not in revs:
             revs.append(filerev)
         rev_index = revs.index(filerev)
         next_revs = revs[:]
 
         # Add parents to next_revs.
         parents = [f.filerev() for f in fctx.parents() if f.path() == path]
         parents_to_add = []
         for parent in parents:
             if parent not in next_revs:
                 parents_to_add.append(parent)
         next_revs[rev_index:rev_index + 1] = util.sort(parents_to_add)
 
         edges = []
         for parent in parents:
             edges.append((rev_index, next_revs.index(parent)))
 
         changerev = fctx.linkrev()
         if changerev <= start_rev:
             node = repo.changelog.node(changerev)
             n_columns_diff = len(next_revs) - len(revs)
             yield (changerev, node, rev_index, edges, len(revs), n_columns_diff)
         if changerev <= stop_rev:
             break
         revs = next_revs
         filerev -= 1
 
 def get_rev_parents(repo, rev):
     return [x for x in repo.changelog.parentrevs(rev) if x != nullrev]
 
 def fix_long_right_edges(edges):
     for (i, (start, end)) in enumerate(edges):
         if end > start:
             edges[i] = (start, end + 1)
 
 def draw_edges(edges, nodeline, interline):
     for (start, end) in edges:
         if start == end + 1:
             interline[2 * end + 1] = "/"
         elif start == end - 1:
             interline[2 * start + 1] = "\\"
         elif start == end:
             interline[2 * start] = "|"
         else:
             nodeline[2 * end] = "+"
             if start > end:
                 (start, end) = (end,start)
             for i in range(2 * start + 1, 2 * end):
                 if nodeline[i] != "+":
                     nodeline[i] = "-"
 
 def format_line(line, level, logstr):
     text = "%-*s %s" % (2 * level, "".join(line), logstr)
     return "%s\n" % text.rstrip()
 
 def get_nodeline_edges_tail(
         node_index, p_node_index, n_columns, n_columns_diff, p_diff, fix_tail):
     if fix_tail and n_columns_diff == p_diff and n_columns_diff != 0:
         # Still going in the same non-vertical direction.
         if n_columns_diff == -1:
             start = max(node_index + 1, p_node_index)
             tail = ["|", " "] * (start - node_index - 1)
             tail.extend(["/", " "] * (n_columns - start))
             return tail
         else:
             return ["\\", " "] * (n_columns - node_index - 1)
     else:
         return ["|", " "] * (n_columns - node_index - 1)
 
 def get_padding_line(ni, n_columns, edges):
     line = []
     line.extend(["|", " "] * ni)
     if (ni, ni - 1) in edges or (ni, ni) in edges:
         # (ni, ni - 1)      (ni, ni)
         # | | | |           | | | |
         # +---o |           | o---+
         # | | c |           | c | |
         # | |/ /            | |/ /
         # | | |             | | |
         c = "|"
     else:
         c = " "
     line.extend([c, " "])
     line.extend(["|", " "] * (n_columns - ni - 1))
     return line
 
 def get_limit(limit_opt):
     if limit_opt:
         try:
             limit = int(limit_opt)
         except ValueError:
             raise Abort(_("limit must be a positive integer"))
         if limit <= 0:
             raise Abort(_("limit must be positive"))
     else:
         limit = sys.maxint
     return limit
 
 def get_revs(repo, rev_opt):
     if rev_opt:
         revs = revrange(repo, rev_opt)
         return (max(revs), min(revs))
     else:
         return (len(repo) - 1, 0)
 
-def graphlog(ui, repo, path=None, **opts):
-    """show revision history alongside an ASCII revision graph
+def ascii(ui, grapher):
+    """prints an ASCII graph of the DAG returned by the grapher
 
-    Print a revision history alongside a revision graph drawn with
-    ASCII characters.
-
-    Nodes printed as an @ character are parents of the working
-    directory.
-    """
+    grapher is a generator that emits tuples with the following elements:
 
-    limit = get_limit(opts["limit"])
-    (start_rev, stop_rev) = get_revs(repo, opts["rev"])
-    stop_rev = max(stop_rev, start_rev - limit + 1)
-    if start_rev == nullrev:
-        return
-    cs_printer = show_changeset(ui, repo, opts)
-    if path:
-        path = canonpath(repo.root, os.getcwd(), path)
-    if path:
-        grapher = filelog_grapher(repo, path, start_rev, stop_rev)
-    else:
-        grapher = revision_grapher(repo, start_rev, stop_rev)
-    repo_parents = repo.dirstate.parents()
+      - Character to use as node's symbol.
+      - List of lines to display as the node's text.
+      - Column of the current node in the set of ongoing edges.
+      - Edges; a list of (col, next_col) indicating the edges between
+        the current node and its parents.
+      - Number of columns (ongoing edges) in the current revision.
+      - The difference between the number of columns (ongoing edges)
+        in the next revision and the number of columns (ongoing edges)
+        in the current revision. That is: -1 means one column removed;
+        0 means no columns added or removed; 1 means one column added.
+    """
     prev_n_columns_diff = 0
     prev_node_index = 0
-
-    for (rev, node, node_index, edges, n_columns, n_columns_diff) in grapher:
+    for (node_ch, node_lines, node_index, edges, n_columns, n_columns_diff) in grapher:
         # node_lines is the list of all text lines to draw alongside the graph
-        ui.pushbuffer()
-        cs_printer.show(rev, node)
-        node_lines = ui.popbuffer().split("\n")[:-1]
 
         if n_columns_diff == -1:
             # Transform
             #
             #     | | |        | | |
             #     o | |  into  o---+
             #     |X /         |/ /
             #     | |          | |
             fix_long_right_edges(edges)
 
         # add_padding_line says whether to rewrite
         #
         #     | | | |        | | | |
         #     | o---+  into  | o---+
         #     |  / /         |   | |  # <--- padding line
         #     o | |          |  / /
         #                    o | |
         add_padding_line = (len(node_lines) > 2 and
                             n_columns_diff == -1 and
                             [x for (x, y) in edges if x + 1 < y])
 
         # fix_nodeline_tail says whether to rewrite
         #
         #     | | o | |        | | o | |
         #     | | |/ /         | | |/ /
         #     | o | |    into  | o / /   # <--- fixed nodeline tail
         #     | |/ /           | |/ /
         #     o | |            o | |
         fix_nodeline_tail = len(node_lines) <= 2 and not add_padding_line
 
         # nodeline is the line containing the node character (typically o)
         nodeline = ["|", " "] * node_index
-        if node in repo_parents:
-            node_ch = "@"
-        else:
-            node_ch = "o"
         nodeline.extend([node_ch, " "])
 
         nodeline.extend(
             get_nodeline_edges_tail(
                 node_index, prev_node_index, n_columns, n_columns_diff,
                 prev_n_columns_diff, fix_nodeline_tail))
 
         # shift_interline is the line containing the non-vertical
         # edges between this entry and the next
         shift_interline = ["|", " "] * node_index
         if n_columns_diff == -1:
             n_spaces = 1
             edge_ch = "/"
         elif n_columns_diff == 0:
             n_spaces = 2
             edge_ch = "|"
         else:
             n_spaces = 3
             edge_ch = "\\"
         shift_interline.extend(n_spaces * [" "])
         shift_interline.extend([edge_ch, " "] * (n_columns - node_index - 1))
 
         # draw edges from the current node to its parents
         draw_edges(edges, nodeline, shift_interline)
 
         # lines is the list of all graph lines to print
         lines = [nodeline]
         if add_padding_line:
             lines.append(get_padding_line(node_index, n_columns, edges))
         lines.append(shift_interline)
 
         # make sure that there are as many graph lines as there are
         # log strings
         while len(node_lines) < len(lines):
             node_lines.append("")
         if len(lines) < len(node_lines):
             extra_interline = ["|", " "] * (n_columns + n_columns_diff)
             while len(lines) < len(node_lines):
                 lines.append(extra_interline)
 
         # print lines
         indentation_level = max(n_columns, n_columns + n_columns_diff)
         for (line, logstr) in zip(lines, node_lines):
             ui.write(format_line(line, indentation_level, logstr))
 
         # ... and start over
         prev_node_index = node_index
         prev_n_columns_diff = n_columns_diff
 
+def graphlog(ui, repo, path=None, **opts):
+    """show revision history alongside an ASCII revision graph
+
+    Print a revision history alongside a revision graph drawn with
+    ASCII characters.
+
+    Nodes printed as an @ character are parents of the working
+    directory.
+    """
+
+    limit = get_limit(opts["limit"])
+    (start_rev, stop_rev) = get_revs(repo, opts["rev"])
+    stop_rev = max(stop_rev, start_rev - limit + 1)
+    if start_rev == nullrev:
+        return
+    if path:
+        path = canonpath(repo.root, os.getcwd(), path)
+    if path:
+        revgrapher = filelog_grapher(repo, path, start_rev, stop_rev)
+    else:
+        revgrapher = revision_grapher(repo, start_rev, stop_rev)
+
+    repo_parents = repo.dirstate.parents()
+    cs_printer = show_changeset(ui, repo, opts)
+    def grapher():
+        for (rev, node, node_index, edges, n_columns, n_columns_diff) in revgrapher:
+            # log_strings is the list of all log strings to draw alongside
+            # the graph.
+            ui.pushbuffer()
+            cs_printer.show(rev, node)
+            log_strings = ui.popbuffer().split("\n")[:-1]
+            if node in repo_parents:
+                node_ch = "@"
+            else:
+                node_ch = "o"
+            yield (node_ch, log_strings, node_index, edges, n_columns, n_columns_diff)
+
+    ascii(ui, grapher())
+
 cmdtable = {
     "glog":
         (graphlog,
          [('l', 'limit', '', _('limit number of changes displayed')),
           ('p', 'patch', False, _('show patch')),
           ('r', 'rev', [], _('show the specified revision or range')),
          ] + templateopts,
          _('hg glog [OPTION]... [FILE]')),
 }