# 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, incorporated herein by reference.

"""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.

"""

import sys

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=sys.maxint):

    """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), colors[p]))

        # Yield and move on

        yield (cur, type, data, (col, color), edges)

        seen = next