graphlog: extract ascii drawing code into graphmod

hgext/graphlog.py

@@ -1,582 +1,379 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 version 2 or any later version.
 
 '''command to view revision graphs from a shell
 
 This extension adds a --graph option to the incoming, outgoing and log
 commands. When this options is given, an ASCII representation of the
 revision graph is also shown.
 '''
 
 from mercurial.cmdutil import show_changeset
 from mercurial.i18n import _
 from mercurial import cmdutil, commands, extensions, scmutil
 from mercurial import hg, util, graphmod, templatekw, revset
 
 cmdtable = {}
 command = cmdutil.command(cmdtable)
 testedwith = 'internal'
 
-def asciiedges(type, char, lines, seen, rev, parents):
-    """adds edge info to changelog DAG walk suitable for ascii()"""
-    if rev not in seen:
-        seen.append(rev)
-    nodeidx = seen.index(rev)
-
-    knownparents = []
-    newparents = []
-    for parent in parents:
-        if parent in seen:
-            knownparents.append(parent)
-        else:
-            newparents.append(parent)
-
-    ncols = len(seen)
-    nextseen = seen[:]
-    nextseen[nodeidx:nodeidx + 1] = newparents
-    edges = [(nodeidx, nextseen.index(p)) for p in knownparents]
-
-    while len(newparents) > 2:
-        # ascii() only knows how to add or remove a single column between two
-        # calls. Nodes with more than two parents break this constraint so we
-        # introduce intermediate expansion lines to grow the active node list
-        # slowly.
-        edges.append((nodeidx, nodeidx))
-        edges.append((nodeidx, nodeidx + 1))
-        nmorecols = 1
-        yield (type, char, lines, (nodeidx, edges, ncols, nmorecols))
-        char = '\\'
-        lines = []
-        nodeidx += 1
-        ncols += 1
-        edges = []
-        del newparents[0]
-
-    if len(newparents) > 0:
-        edges.append((nodeidx, nodeidx))
-    if len(newparents) > 1:
-        edges.append((nodeidx, nodeidx + 1))
-    nmorecols = len(nextseen) - ncols
-    seen[:] = nextseen
-    yield (type, char, lines, (nodeidx, edges, ncols, nmorecols))
-
-def _fixlongrightedges(edges):
-    for (i, (start, end)) in enumerate(edges):
-        if end > start:
-            edges[i] = (start, end + 1)
-
-def _getnodelineedgestail(
-        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 _drawedges(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:
-            if 2 * end >= len(nodeline):
-                continue
-            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 _getpaddingline(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 asciistate():
-    """returns the initial value for the "state" argument to ascii()"""
-    return [0, 0]
-
-def ascii(ui, state, type, char, text, coldata):
-    """prints an ASCII graph of the DAG
-
-    takes the following arguments (one call per node in the graph):
-
-      - ui to write to
-      - Somewhere to keep the needed state in (init to asciistate())
-      - Column of the current node in the set of ongoing edges.
-      - Type indicator of node data, usually 'C' for changesets.
-      - Payload: (char, lines):
-        - Character to use as node's symbol.
-        - List of lines to display as the node's text.
-      - 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.
-    """
-
-    idx, edges, ncols, coldiff = coldata
-    assert -2 < coldiff < 2
-    if coldiff == -1:
-        # Transform
-        #
-        #     | | |        | | |
-        #     o | |  into  o---+
-        #     |X /         |/ /
-        #     | |          | |
-        _fixlongrightedges(edges)
-
-    # add_padding_line says whether to rewrite
-    #
-    #     | | | |        | | | |
-    #     | o---+  into  | o---+
-    #     |  / /         |   | |  # <--- padding line
-    #     o | |          |  / /
-    #                    o | |
-    add_padding_line = (len(text) > 2 and coldiff == -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(text) <= 2 and not add_padding_line
-
-    # nodeline is the line containing the node character (typically o)
-    nodeline = ["|", " "] * idx
-    nodeline.extend([char, " "])
-
-    nodeline.extend(
-        _getnodelineedgestail(idx, state[1], ncols, coldiff,
-                              state[0], fix_nodeline_tail))
-
-    # shift_interline is the line containing the non-vertical
-    # edges between this entry and the next
-    shift_interline = ["|", " "] * idx
-    if coldiff == -1:
-        n_spaces = 1
-        edge_ch = "/"
-    elif coldiff == 0:
-        n_spaces = 2
-        edge_ch = "|"
-    else:
-        n_spaces = 3
-        edge_ch = "\\"
-    shift_interline.extend(n_spaces * [" "])
-    shift_interline.extend([edge_ch, " "] * (ncols - idx - 1))
-
-    # draw edges from the current node to its parents
-    _drawedges(edges, nodeline, shift_interline)
-
-    # lines is the list of all graph lines to print
-    lines = [nodeline]
-    if add_padding_line:
-        lines.append(_getpaddingline(idx, ncols, edges))
-    lines.append(shift_interline)
-
-    # make sure that there are as many graph lines as there are
-    # log strings
-    while len(text) < len(lines):
-        text.append("")
-    if len(lines) < len(text):
-        extra_interline = ["|", " "] * (ncols + coldiff)
-        while len(lines) < len(text):
-            lines.append(extra_interline)
-
-    # print lines
-    indentation_level = max(ncols, ncols + coldiff)
-    for (line, logstr) in zip(lines, text):
-        ln = "%-*s %s" % (2 * indentation_level, "".join(line), logstr)
-        ui.write(ln.rstrip() + '\n')
-
-    # ... and start over
-    state[0] = coldiff
-    state[1] = idx
-
 def _checkunsupportedflags(pats, opts):
     for op in ["newest_first"]:
         if op in opts and opts[op]:
             raise util.Abort(_("-G/--graph option is incompatible with --%s")
                              % op.replace("_", "-"))
 
 def _makefilematcher(repo, pats, followfirst):
     # When displaying a revision with --patch --follow FILE, we have
     # to know which file of the revision must be diffed. With
     # --follow, we want the names of the ancestors of FILE in the
     # revision, stored in "fcache". "fcache" is populated by
     # reproducing the graph traversal already done by --follow revset
     # and relating linkrevs to file names (which is not "correct" but
     # good enough).
     fcache = {}
     fcacheready = [False]
     pctx = repo['.']
     wctx = repo[None]
 
     def populate():
         for fn in pats:
             for i in ((pctx[fn],), pctx[fn].ancestors(followfirst=followfirst)):
                 for c in i:
                     fcache.setdefault(c.linkrev(), set()).add(c.path())
 
     def filematcher(rev):
         if not fcacheready[0]:
             # Lazy initialization
             fcacheready[0] = True
             populate()
         return scmutil.match(wctx, fcache.get(rev, []), default='path')
 
     return filematcher
 
 def _makelogrevset(repo, pats, opts, revs):
     """Return (expr, filematcher) where expr is a revset string built
     from log options and file patterns or None. If --stat or --patch
     are not passed filematcher is None. Otherwise it is a callable
     taking a revision number and returning a match objects filtering
     the files to be detailed when displaying the revision.
     """
     opt2revset = {
         'no_merges':        ('not merge()', None),
         'only_merges':      ('merge()', None),
         '_ancestors':       ('ancestors(%(val)s)', None),
         '_fancestors':      ('_firstancestors(%(val)s)', None),
         '_descendants':     ('descendants(%(val)s)', None),
         '_fdescendants':    ('_firstdescendants(%(val)s)', None),
         '_matchfiles':      ('_matchfiles(%(val)s)', None),
         'date':             ('date(%(val)r)', None),
         'branch':           ('branch(%(val)r)', ' or '),
         '_patslog':         ('filelog(%(val)r)', ' or '),
         '_patsfollow':      ('follow(%(val)r)', ' or '),
         '_patsfollowfirst': ('_followfirst(%(val)r)', ' or '),
         'keyword':          ('keyword(%(val)r)', ' or '),
         'prune':            ('not (%(val)r or ancestors(%(val)r))', ' and '),
         'user':             ('user(%(val)r)', ' or '),
         }
 
     opts = dict(opts)
     # follow or not follow?
     follow = opts.get('follow') or opts.get('follow_first')
     followfirst = opts.get('follow_first') and 1 or 0
     # --follow with FILE behaviour depends on revs...
     startrev = revs[0]
     followdescendants = (len(revs) > 1 and revs[0] < revs[1]) and 1 or 0
 
     # branch and only_branch are really aliases and must be handled at
     # the same time
     opts['branch'] = opts.get('branch', []) + opts.get('only_branch', [])
     opts['branch'] = [repo.lookupbranch(b) for b in opts['branch']]
     # pats/include/exclude are passed to match.match() directly in
     # _matchfile() revset but walkchangerevs() builds its matcher with
     # scmutil.match(). The difference is input pats are globbed on
     # platforms without shell expansion (windows).
     pctx = repo[None]
     match, pats = scmutil.matchandpats(pctx, pats, opts)
     slowpath = match.anypats() or (match.files() and opts.get('removed'))
     if not slowpath:
         for f in match.files():
             if follow and f not in pctx:
                 raise util.Abort(_('cannot follow file not in parent '
                                    'revision: "%s"') % f)
             filelog = repo.file(f)
             if not len(filelog):
                 # A zero count may be a directory or deleted file, so
                 # try to find matching entries on the slow path.
                 if follow:
                     raise util.Abort(
                         _('cannot follow nonexistent file: "%s"') % f)
                 slowpath = True
     if slowpath:
         # See cmdutil.walkchangerevs() slow path.
         #
         if follow:
             raise util.Abort(_('can only follow copies/renames for explicit '
                                'filenames'))
         # pats/include/exclude cannot be represented as separate
         # revset expressions as their filtering logic applies at file
         # level. For instance "-I a -X a" matches a revision touching
         # "a" and "b" while "file(a) and not file(b)" does
         # not. Besides, filesets are evaluated against the working
         # directory.
         matchargs = ['r:', 'd:relpath']
         for p in pats:
             matchargs.append('p:' + p)
         for p in opts.get('include', []):
             matchargs.append('i:' + p)
         for p in opts.get('exclude', []):
             matchargs.append('x:' + p)
         matchargs = ','.join(('%r' % p) for p in matchargs)
         opts['_matchfiles'] = matchargs
     else:
         if follow:
             fpats = ('_patsfollow', '_patsfollowfirst')
             fnopats = (('_ancestors', '_fancestors'),
                        ('_descendants', '_fdescendants'))
             if pats:
                 # follow() revset inteprets its file argument as a
                 # manifest entry, so use match.files(), not pats.
                 opts[fpats[followfirst]] = list(match.files())
             else:
                 opts[fnopats[followdescendants][followfirst]] = str(startrev)
         else:
             opts['_patslog'] = list(pats)
 
     filematcher = None
     if opts.get('patch') or opts.get('stat'):
         if follow:
             filematcher = _makefilematcher(repo, pats, followfirst)
         else:
             filematcher = lambda rev: match
 
     expr = []
     for op, val in opts.iteritems():
         if not val:
             continue
         if op not in opt2revset:
             continue
         revop, andor = opt2revset[op]
         if '%(val)' not in revop:
             expr.append(revop)
         else:
             if not isinstance(val, list):
                 e = revop % {'val': val}
             else:
                 e = '(' + andor.join((revop % {'val': v}) for v in val) + ')'
             expr.append(e)
 
     if expr:
         expr = '(' + ' and '.join(expr) + ')'
     else:
         expr = None
     return expr, filematcher
 
 def getlogrevs(repo, pats, opts):
     """Return (revs, expr, filematcher) where revs is an iterable of
     revision numbers, expr is a revset string built from log options
     and file patterns or None, and used to filter 'revs'. If --stat or
     --patch are not passed filematcher is None. Otherwise it is a
     callable taking a revision number and returning a match objects
     filtering the files to be detailed when displaying the revision.
     """
     def increasingrevs(repo, revs, matcher):
         # The sorted input rev sequence is chopped in sub-sequences
         # which are sorted in ascending order and passed to the
         # matcher. The filtered revs are sorted again as they were in
         # the original sub-sequence. This achieve several things:
         #
         # - getlogrevs() now returns a generator which behaviour is
         #   adapted to log need. First results come fast, last ones
         #   are batched for performances.
         #
         # - revset matchers often operate faster on revision in
         #   changelog order, because most filters deal with the
         #   changelog.
         #
         # - revset matchers can reorder revisions. "A or B" typically
         #   returns returns the revision matching A then the revision
         #   matching B. We want to hide this internal implementation
         #   detail from the caller, and sorting the filtered revision
         #   again achieves this.
         for i, window in cmdutil.increasingwindows(0, len(revs), windowsize=1):
             orevs = revs[i:i + window]
             nrevs = set(matcher(repo, sorted(orevs)))
             for rev in orevs:
                 if rev in nrevs:
                     yield rev
 
     if not len(repo):
         return iter([]), None, None
     # Default --rev value depends on --follow but --follow behaviour
     # depends on revisions resolved from --rev...
     follow = opts.get('follow') or opts.get('follow_first')
     if opts.get('rev'):
         revs = scmutil.revrange(repo, opts['rev'])
     else:
         if follow and len(repo) > 0:
             revs = scmutil.revrange(repo, ['.:0'])
         else:
             revs = range(len(repo) - 1, -1, -1)
     if not revs:
         return iter([]), None, None
     expr, filematcher = _makelogrevset(repo, pats, opts, revs)
     if expr:
         matcher = revset.match(repo.ui, expr)
         revs = increasingrevs(repo, revs, matcher)
     if not opts.get('hidden'):
         # --hidden is still experimental and not worth a dedicated revset
         # yet. Fortunately, filtering revision number is fast.
         revs = (r for r in revs if r not in repo.changelog.hiddenrevs)
     else:
         revs = iter(revs)
     return revs, expr, filematcher
 
 def generate(ui, dag, displayer, showparents, edgefn, getrenamed=None,
              filematcher=None):
-    seen, state = [], asciistate()
+    seen, state = [], graphmod.asciistate()
     for rev, type, ctx, parents in dag:
         char = 'o'
         if ctx.node() in showparents:
             char = '@'
         elif ctx.obsolete():
             char = 'x'
         copies = None
         if getrenamed and ctx.rev():
             copies = []
             for fn in ctx.files():
                 rename = getrenamed(fn, ctx.rev())
                 if rename:
                     copies.append((fn, rename[0]))
         revmatchfn = None
         if filematcher is not None:
             revmatchfn = filematcher(ctx.rev())
         displayer.show(ctx, copies=copies, matchfn=revmatchfn)
         lines = displayer.hunk.pop(rev).split('\n')
         if not lines[-1]:
             del lines[-1]
         displayer.flush(rev)
         edges = edgefn(type, char, lines, seen, rev, parents)
         for type, char, lines, coldata in edges:
-            ascii(ui, state, type, char, lines, coldata)
+            graphmod.ascii(ui, state, type, char, lines, coldata)
     displayer.close()
 
 @command('glog',
     [('f', 'follow', None,
      _('follow changeset history, or file history across copies and renames')),
     ('', 'follow-first', None,
      _('only follow the first parent of merge changesets (DEPRECATED)')),
     ('d', 'date', '', _('show revisions matching date spec'), _('DATE')),
     ('C', 'copies', None, _('show copied files')),
     ('k', 'keyword', [],
      _('do case-insensitive search for a given text'), _('TEXT')),
     ('r', 'rev', [], _('show the specified revision or range'), _('REV')),
     ('', 'removed', None, _('include revisions where files were removed')),
     ('m', 'only-merges', None, _('show only merges (DEPRECATED)')),
     ('u', 'user', [], _('revisions committed by user'), _('USER')),
     ('', 'only-branch', [],
      _('show only changesets within the given named branch (DEPRECATED)'),
      _('BRANCH')),
     ('b', 'branch', [],
      _('show changesets within the given named branch'), _('BRANCH')),
     ('P', 'prune', [],
      _('do not display revision or any of its ancestors'), _('REV')),
     ('', 'hidden', False, _('show hidden changesets (DEPRECATED)')),
     ] + commands.logopts + commands.walkopts,
     _('[OPTION]... [FILE]'))
 def graphlog(ui, repo, *pats, **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.
     """
 
     revs, expr, filematcher = getlogrevs(repo, pats, opts)
     revs = sorted(revs, reverse=1)
     limit = cmdutil.loglimit(opts)
     if limit is not None:
         revs = revs[:limit]
     revdag = graphmod.dagwalker(repo, revs)
 
     getrenamed = None
     if opts.get('copies'):
         endrev = None
         if opts.get('rev'):
             endrev = max(scmutil.revrange(repo, opts.get('rev'))) + 1
         getrenamed = templatekw.getrenamedfn(repo, endrev=endrev)
     displayer = show_changeset(ui, repo, opts, buffered=True)
     showparents = [ctx.node() for ctx in repo[None].parents()]
-    generate(ui, revdag, displayer, showparents, asciiedges, getrenamed,
-             filematcher)
+    generate(ui, revdag, displayer, showparents, graphmod.asciiedges,
+             getrenamed, filematcher)
 
 def graphrevs(repo, nodes, opts):
     limit = cmdutil.loglimit(opts)
     nodes.reverse()
     if limit is not None:
         nodes = nodes[:limit]
     return graphmod.nodes(repo, nodes)
 
 def goutgoing(ui, repo, dest=None, **opts):
     """show the outgoing changesets alongside an ASCII revision graph
 
     Print the outgoing changesets alongside a revision graph drawn with
     ASCII characters.
 
     Nodes printed as an @ character are parents of the working
     directory.
     """
 
     _checkunsupportedflags([], opts)
     o = hg._outgoing(ui, repo, dest, opts)
     if o is None:
         return
 
     revdag = graphrevs(repo, o, opts)
     displayer = show_changeset(ui, repo, opts, buffered=True)
     showparents = [ctx.node() for ctx in repo[None].parents()]
-    generate(ui, revdag, displayer, showparents, asciiedges)
+    generate(ui, revdag, displayer, showparents, graphmod.asciiedges)
 
 def gincoming(ui, repo, source="default", **opts):
     """show the incoming changesets alongside an ASCII revision graph
 
     Print the incoming changesets alongside a revision graph drawn with
     ASCII characters.
 
     Nodes printed as an @ character are parents of the working
     directory.
     """
     def subreporecurse():
         return 1
 
     _checkunsupportedflags([], opts)
     def display(other, chlist, displayer):
         revdag = graphrevs(other, chlist, opts)
         showparents = [ctx.node() for ctx in repo[None].parents()]
-        generate(ui, revdag, displayer, showparents, asciiedges)
+        generate(ui, revdag, displayer, showparents, graphmod.asciiedges)
 
     hg._incoming(display, subreporecurse, ui, repo, source, opts, buffered=True)
 
 def uisetup(ui):
     '''Initialize the extension.'''
     _wrapcmd('log', commands.table, graphlog)
     _wrapcmd('incoming', commands.table, gincoming)
     _wrapcmd('outgoing', commands.table, goutgoing)
 
 def _wrapcmd(cmd, table, wrapfn):
     '''wrap the command'''
     def graph(orig, *args, **kwargs):
         if kwargs['graph']:
             return wrapfn(*args, **kwargs)
         return orig(*args, **kwargs)
     entry = extensions.wrapcommand(table, cmd, graph)
     entry[1].append(('G', 'graph', None, _("show the revision DAG")))

mercurial/graphmod.py

@@ -1,165 +1,368 b''
 # Revision graph generator for Mercurial
 #
 # Copyright 2008 Dirkjan Ochtman <[e-mail]>
 # Copyright 2007 Joel Rosdahl <[e-mail]>
 #
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2 or any later version.
 
 """supports walking the history as DAGs suitable for graphical output
 
 The most basic format we use is that of::
 
   (id, type, data, [parentids])
 
 The node and parent ids are arbitrary integers which identify a node in the
 context of the graph returned. Type is a constant specifying the node type.
 Data depends on type.
 """
 
 from mercurial.node import nullrev
 import util
 
 CHANGESET = 'C'
 
 def dagwalker(repo, revs):
     """cset DAG generator yielding (id, CHANGESET, ctx, [parentids]) tuples
 
     This generator function walks through revisions (which should be ordered
     from bigger to lower). It returns a tuple for each node. The node and parent
     ids are arbitrary integers which identify a node in the context of the graph
     returned.
     """
     if not revs:
         return
 
     cl = repo.changelog
     lowestrev = min(revs)
     gpcache = {}
 
     knownrevs = set(revs)
     for rev in revs:
         ctx = repo[rev]
         parents = sorted(set([p.rev() for p in ctx.parents()
                               if p.rev() in knownrevs]))
         mpars = [p.rev() for p in ctx.parents() if
                  p.rev() != nullrev and p.rev() not in parents]
 
         for mpar in mpars:
             gp = gpcache.get(mpar)
             if gp is None:
                 gp = gpcache[mpar] = grandparent(cl, lowestrev, revs, mpar)
             if not gp:
                 parents.append(mpar)
             else:
                 parents.extend(g for g in gp if g not in parents)
 
         yield (ctx.rev(), CHANGESET, ctx, parents)
 
 def nodes(repo, nodes):
     """cset DAG generator yielding (id, CHANGESET, ctx, [parentids]) tuples
 
     This generator function walks the given nodes. It only returns parents
     that are in nodes, too.
     """
     include = set(nodes)
     for node in nodes:
         ctx = repo[node]
         parents = set([p.rev() for p in ctx.parents() if p.node() in include])
         yield (ctx.rev(), CHANGESET, ctx, sorted(parents))
 
 def colored(dag, repo):
     """annotates a DAG with colored edge information
 
     For each DAG node this function emits tuples::
 
       (id, type, data, (col, color), [(col, nextcol, color)])
 
     with the following new elements:
 
       - Tuple (col, color) with column and color index for the current node
       - A list of tuples indicating the edges between the current node and its
         parents.
     """
     seen = []
     colors = {}
     newcolor = 1
     config = {}
 
     for key, val in repo.ui.configitems('graph'):
         if '.' in key:
             branch, setting = key.rsplit('.', 1)
             # Validation
             if setting == "width" and val.isdigit():
                 config.setdefault(branch, {})[setting] = int(val)
             elif setting == "color" and val.isalnum():
                 config.setdefault(branch, {})[setting] = val
 
     if config:
         getconf = util.lrucachefunc(
             lambda rev: config.get(repo[rev].branch(), {}))
     else:
         getconf = lambda rev: {}
 
     for (cur, type, data, parents) in dag:
 
         # Compute seen and next
         if cur not in seen:
             seen.append(cur) # new head
             colors[cur] = newcolor
             newcolor += 1
 
         col = seen.index(cur)
         color = colors.pop(cur)
         next = seen[:]
 
         # Add parents to next
         addparents = [p for p in parents if p not in next]
         next[col:col + 1] = addparents
 
         # Set colors for the parents
         for i, p in enumerate(addparents):
             if not i:
                 colors[p] = color
             else:
                 colors[p] = newcolor
                 newcolor += 1
 
         # Add edges to the graph
         edges = []
         for ecol, eid in enumerate(seen):
             if eid in next:
                 bconf = getconf(eid)
                 edges.append((
                     ecol, next.index(eid), colors[eid],
                     bconf.get('width', -1),
                     bconf.get('color', '')))
             elif eid == cur:
                 for p in parents:
                     bconf = getconf(p)
                     edges.append((
                         ecol, next.index(p), color,
                         bconf.get('width', -1),
                         bconf.get('color', '')))
 
         # Yield and move on
         yield (cur, type, data, (col, color), edges)
         seen = next
 
 def grandparent(cl, lowestrev, roots, head):
     """Return all ancestors of head in roots which revision is
     greater or equal to lowestrev.
     """
     pending = set([head])
     seen = set()
     kept = set()
     llowestrev = max(nullrev, lowestrev)
     while pending:
         r = pending.pop()
         if r >= llowestrev and r not in seen:
             if r in roots:
                 kept.add(r)
             else:
                 pending.update([p for p in cl.parentrevs(r)])
             seen.add(r)
     return sorted(kept)
+
+def asciiedges(type, char, lines, seen, rev, parents):
+    """adds edge info to changelog DAG walk suitable for ascii()"""
+    if rev not in seen:
+        seen.append(rev)
+    nodeidx = seen.index(rev)
+
+    knownparents = []
+    newparents = []
+    for parent in parents:
+        if parent in seen:
+            knownparents.append(parent)
+        else:
+            newparents.append(parent)
+
+    ncols = len(seen)
+    nextseen = seen[:]
+    nextseen[nodeidx:nodeidx + 1] = newparents
+    edges = [(nodeidx, nextseen.index(p)) for p in knownparents]
+
+    while len(newparents) > 2:
+        # ascii() only knows how to add or remove a single column between two
+        # calls. Nodes with more than two parents break this constraint so we
+        # introduce intermediate expansion lines to grow the active node list
+        # slowly.
+        edges.append((nodeidx, nodeidx))
+        edges.append((nodeidx, nodeidx + 1))
+        nmorecols = 1
+        yield (type, char, lines, (nodeidx, edges, ncols, nmorecols))
+        char = '\\'
+        lines = []
+        nodeidx += 1
+        ncols += 1
+        edges = []
+        del newparents[0]
+
+    if len(newparents) > 0:
+        edges.append((nodeidx, nodeidx))
+    if len(newparents) > 1:
+        edges.append((nodeidx, nodeidx + 1))
+    nmorecols = len(nextseen) - ncols
+    seen[:] = nextseen
+    yield (type, char, lines, (nodeidx, edges, ncols, nmorecols))
+
+def _fixlongrightedges(edges):
+    for (i, (start, end)) in enumerate(edges):
+        if end > start:
+            edges[i] = (start, end + 1)
+
+def _getnodelineedgestail(
+        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 _drawedges(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:
+            if 2 * end >= len(nodeline):
+                continue
+            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 _getpaddingline(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 asciistate():
+    """returns the initial value for the "state" argument to ascii()"""
+    return [0, 0]
+
+def ascii(ui, state, type, char, text, coldata):
+    """prints an ASCII graph of the DAG
+
+    takes the following arguments (one call per node in the graph):
+
+      - ui to write to
+      - Somewhere to keep the needed state in (init to asciistate())
+      - Column of the current node in the set of ongoing edges.
+      - Type indicator of node data, usually 'C' for changesets.
+      - Payload: (char, lines):
+        - Character to use as node's symbol.
+        - List of lines to display as the node's text.
+      - 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.
+    """
+
+    idx, edges, ncols, coldiff = coldata
+    assert -2 < coldiff < 2
+    if coldiff == -1:
+        # Transform
+        #
+        #     | | |        | | |
+        #     o | |  into  o---+
+        #     |X /         |/ /
+        #     | |          | |
+        _fixlongrightedges(edges)
+
+    # add_padding_line says whether to rewrite
+    #
+    #     | | | |        | | | |
+    #     | o---+  into  | o---+
+    #     |  / /         |   | |  # <--- padding line
+    #     o | |          |  / /
+    #                    o | |
+    add_padding_line = (len(text) > 2 and coldiff == -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(text) <= 2 and not add_padding_line
+
+    # nodeline is the line containing the node character (typically o)
+    nodeline = ["|", " "] * idx
+    nodeline.extend([char, " "])
+
+    nodeline.extend(
+        _getnodelineedgestail(idx, state[1], ncols, coldiff,
+                              state[0], fix_nodeline_tail))
+
+    # shift_interline is the line containing the non-vertical
+    # edges between this entry and the next
+    shift_interline = ["|", " "] * idx
+    if coldiff == -1:
+        n_spaces = 1
+        edge_ch = "/"
+    elif coldiff == 0:
+        n_spaces = 2
+        edge_ch = "|"
+    else:
+        n_spaces = 3
+        edge_ch = "\\"
+    shift_interline.extend(n_spaces * [" "])
+    shift_interline.extend([edge_ch, " "] * (ncols - idx - 1))
+
+    # draw edges from the current node to its parents
+    _drawedges(edges, nodeline, shift_interline)
+
+    # lines is the list of all graph lines to print
+    lines = [nodeline]
+    if add_padding_line:
+        lines.append(_getpaddingline(idx, ncols, edges))
+    lines.append(shift_interline)
+
+    # make sure that there are as many graph lines as there are
+    # log strings
+    while len(text) < len(lines):
+        text.append("")
+    if len(lines) < len(text):
+        extra_interline = ["|", " "] * (ncols + coldiff)
+        while len(lines) < len(text):
+            lines.append(extra_interline)
+
+    # print lines
+    indentation_level = max(ncols, ncols + coldiff)
+    for (line, logstr) in zip(lines, text):
+        ln = "%-*s %s" % (2 * indentation_level, "".join(line), logstr)
+        ui.write(ln.rstrip() + '\n')
+
+    # ... and start over
+    state[0] = coldiff
+    state[1] = idx