--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mercurial/graphmod.py	Wed Jun 18 07:06:41 2008 +0200
@@ -0,0 +1,74 @@
+# Revision graph generator for Mercurial
+#
+# Copyright 2008 Dirkjan Ochtman <dirkjan@ochtman.nl>
+# Copyright 2007 Joel Rosdahl <joel@rosdahl.net>
+#
+# This software may be used and distributed according to the terms of
+# the GNU General Public License, incorporated herein by reference.
+
+from node import nullrev, short
+import ui, hg, util, templatefilters
+
+def graph(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 node
+      - Column and color for the current node
+      - Edges; a list of (col, next_col, color) indicating the edges between
+        the current node and its parents.
+      - First line of the changeset description
+      - The changeset author
+      - The changeset date/time
+    """
+
+    assert start_rev >= stop_rev
+    curr_rev = start_rev
+    revs = []
+    cl = repo.changelog
+    colors = {}
+    new_color = 1
+
+    while curr_rev >= stop_rev:
+        node = cl.node(curr_rev)
+
+        # Compute revs and next_revs
+        if curr_rev not in revs:
+            revs.append(curr_rev) # new head
+            colors[curr_rev] = new_color
+            new_color += 1
+
+        idx = revs.index(curr_rev)
+        color = colors.pop(curr_rev)
+        next = revs[:]
+
+        # Add parents to next_revs
+        parents = [x for x in cl.parentrevs(curr_rev) if x != nullrev]
+        addparents = [p for p in parents if p not in next]
+        next[idx:idx + 1] = addparents
+
+        # Set colors for the parents
+        for i, p in enumerate(addparents):
+            if not i:
+                colors[p] = color
+            else:
+                colors[p] = new_color
+                new_color += 1
+
+        # Add edges to the graph
+        edges = []
+        for col, r in enumerate(revs):
+            if r in next:
+                edges.append((col, next.index(r), colors[r]))
+            elif r == curr_rev:
+                for p in parents:
+                    edges.append((col, next.index(p), colors[p]))
+
+        # Yield and move on
+        yield (repo.changectx(curr_rev), (idx, color), edges)
+        revs = next
+        curr_rev -= 1