view mercurial/graphmod.py @ 12296:d7fff529d85d

clone: only use stream when we understand the revlog format

This patch fixes issues with stream cloning in the presense of parentdelta,
lwcopy and similar additions that change the interpretation of the revlog
format, or the format itself.

Currently, the stream capability is sent like this:
stream=<version of changelog>

But the client doesn't actually check the version number; also, it only checks
the changelog and it doesn't capture the interpretation-changes and
flag-changes in parentdelta and lwcopy.

This patch removes the 'stream' capability whenever we use a non-basic revlog
format, to prevent old clients from receiving incorrect data. In those cases,
a new capability called 'streamreqs' is added instead. Instead of a revlog
version, it comes with a list of revlog-format relevant requirements, which
are a subset of the repository requirements, excluding things that are not
relevant for stream.

New clients use this to determine whether or not they can stream. Old clients
only look for the 'stream' capability, as always. New servers will still send
this when serving old repositories.

# 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

CHANGESET = 'C'

def revisions(repo, start, stop):
    """cset DAG generator yielding (id, CHANGESET, ctx, [parentids]) tuples

    This generator function walks through the revision history from revision
    start to revision stop (which must be less than or equal to start). 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.
    """
    cur = start
    while cur >= stop:
        ctx = repo[cur]
        parents = [p.rev() for p in ctx.parents() if p.rev() != nullrev]
        yield (cur, CHANGESET, ctx, sorted(parents))
        cur -= 1

def filerevs(repo, path, start, stop, limit=None):
    """file cset DAG generator yielding (id, CHANGESET, ctx, [parentids]) tuples

    This generator function walks through the revision history of a single
    file from revision start down to revision stop.
    """
    filerev = len(repo.file(path)) - 1
    rev = stop + 1
    count = 0
    while filerev >= 0 and rev > stop:
        fctx = repo.filectx(path, fileid=filerev)
        parents = [f.linkrev() for f in fctx.parents() if f.path() == path]
        rev = fctx.rev()
        if rev <= start:
            yield (rev, CHANGESET, fctx.changectx(), sorted(parents))
            count += 1
            if count == limit:
                break
        filerev -= 1

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 = [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