view mercurial/graphmod.py @ 14365:a8e3931e3fb5

revlog: linearize created changegroups in generaldelta revlogs This greatly improves the speed of the bundling process, and often reduces the bundle size considerably. (Although if the repository is already ordered, this has little effect on both time and bundle size.) For non-generaldelta clients, the reduced bundle size translates to a reduced repository size, similar to shrinking the revlogs (which uses the exact same algorithm). For generaldelta clients the difference is minor. When the new bundle format comes, reordering will not be necessary since we can then store the deltaparent relationsships directly. The eventual default behavior for clients and servers is presented in the table below, where "new" implies support for GD as well as the new bundle format: old client new client old server old bundle, no reorder old bundle, no reorder new server, non-GD old bundle, no reorder[1] old bundle, no reorder[2] new server, GD old bundle, reorder[3] new bundle, no reorder[4] [1] reordering is expensive on the server in this case, skip it [2] client can choose to do its own redelta here [3] reordering is needed because otherwise the pull does a lot of extra work on the server [4] reordering isn't needed because client can get deltabase in bundle format Currently, the default is to reorder on GD-servers, and not otherwise. A new setting, bundle.reorder, has been added to override the default reordering behavior. It can be set to either 'auto' (the default), or any true or false value as a standard boolean setting, to either force the reordering on or off regardless of generaldelta. Some timing data from a relatively branch test repository follows. All bundling is done with --all --type none options. Non-generaldelta, non-shrunk repo: ----------------------------------- Size: 276M Without reorder (default): Bundle time: 14.4 seconds Bundle size: 939M With reorder: Bundle time: 1 minute, 29.3 seconds Bundle size: 381M Generaldelta, non-shrunk repo: ----------------------------------- Size: 87M Without reorder: Bundle time: 2 minutes, 1.4 seconds Bundle size: 939M With reorder (default): Bundle time: 25.5 seconds Bundle size: 381M
author Sune Foldager <cryo@cyanite.org>
date Wed, 18 May 2011 23:26:26 +0200
parents 03e1c2d35c6a
children 5e50982c633c
line wrap: on
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# 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 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

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):
    """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
    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:
                edges.append((ecol, next.index(eid), colors[eid]))
            elif eid == cur:
                for p in parents:
                    edges.append((ecol, next.index(p), 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)