# 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

import util

import heapq

CHANGESET = 'C'

    """yield revision from heads to roots one (topo) branch after the other.

    This function aims to be used by a graph generator that wishes to minimize

    the amount of parallel branches and their interleaving.

    Example iteration order:

      o  4

      |

      o  1

      |

      | o  3

      | |

      | o  2

      |/

      o  0

    Currently consider every changeset under a merge to be on the same branch

    using revision number to sort them.

    ### Quick summary of the algorithm

    #

    # This function is based around a "retention" principle. We keep revisions

    # in memory until we are ready to emit a whole branch that immediately

    # "merge" into an existing one. This reduce the number of branch "ongoing"

    # at the same time.

    #

    # During iteration revs are split into two groups:

    # A) revision already emitted

    # B) revision in "retention". They are stored as different subgroups.

    #

    # for each REV, we do the follow logic:

    #

    #   a) if REV is a parent of (A), we will emit it. But before emitting it,

    #   we'll "free" all the revs from subgroup in (B) that were waiting for

    #   REV to be available. So we emit all revision of such subgroup before

    #   emitting REV

    #

    #   b) else, we'll search for a subgroup in (B) awaiting for REV to be

    #   available, if such subgroup exist, we add REV to it and the subgroup is

    #   now awaiting for REV.parents() to be available.

    #

    #   c) finally if no such group existed in (B), we create a new subgroup.

    #

    #

    # To bootstrap the algorithm, we emit the tipmost revision.

    revs.sort(reverse=True)

    # Set of parents of revision that have been yield. They can be considered

    # unblocked as the graph generator is already aware of them so there is no

    # need to delay the one that reference them.

    # list of group waiting to be displayed, each group is defined by:

    #

    #   (revs:    lists of revs waiting to be displayed,

    #    blocked: set of that cannot be displayed before those in 'revs')

    #

    # The second value ('blocked') correspond to parents of any revision in the

    # group ('revs') that is not itself contained in the group. The main idea

    # of this algorithm is to delay as much as possible the emission of any

    # revision.  This means waiting for the moment we are about to display

    # theses parents to display the revs in a group.

    #

    # This first implementation is smart until it meet a merge: it will emit

    # revs as soon as any parents is about to be emitted and can grow an

    # arbitrary number of revs in 'blocked'. In practice this mean we properly

    # retains new branches but give up on any special ordering for ancestors of

    # merges. The implementation can be improved to handle this better.

    #

    # The first subgroup is special. It correspond to all the revision that

    # were already emitted. The 'revs' lists is expected to be empty and the

    # 'blocked' set contains the parents revisions of already emitted revision.

    #

    # You could pre-seed the <parents> set of groups[0] to a specific

    # changesets to select what the first emitted branch should be.

    groups = [([], unblocked)]

    pendingheap = []

    pendingset = set()

    heapq.heapify(pendingheap)

    heappop = heapq.heappop

    heappush = heapq.heappush

    for currentrev in revs:

        # Heap works with smallest element, we want highest so we invert

        if currentrev not in pendingset:

            heappush(pendingheap, -currentrev)

            pendingset.add(currentrev)

        # iterates on pending rev until after the current rev have been

        # processeed.

        rev = None

        while rev != currentrev:

            rev = -heappop(pendingheap)

            pendingset.remove(rev)

            # Seek for a subgroup blocked, waiting for the current revision.

            matching = [i for i, g in enumerate(groups) if rev in g[1]]

            if matching:

                # The main idea is to gather together all sets that await on

                # the same revision.

                #

                # This merging is done at the time we are about to add this

                # common awaited to the subgroup for simplicity purpose. Such

                # merge could happen sooner when we update the "blocked" set of

                # revision.

                #

                # We also always keep the oldest subgroup first. We can

                # probably improve the behavior by having the longuest set

                # first. That way, graph algorythms could minimise the length

                # of parallele lines their draw. This is currently not done.

                targetidx = matching.pop(0)

                trevs, tparents = groups[targetidx]

                for i in matching:

                    gr = groups[i]

                    trevs.extend(gr[0])

                    tparents |= gr[1]

                # delete all merged subgroups (but the one we keep) (starting

                # from the last subgroup for performance and sanity reason)

                for i in reversed(matching):

                    del groups[i]

            else:

                # This is a new head. We create a new subgroup for it.

                targetidx = len(groups)

                groups.append(([], set([rev])))

            gr = groups[targetidx]

            # We now adds the current nodes to this subgroups. This is done

            # after the subgroup merging because all elements from a subgroup

            # that relied on this rev must preceed it.

            #

            # we also update the <parents> set to includes the parents on the

            # new nodes.

            if rev == currentrev: # only display stuff in rev

                gr[0].append(rev)

            gr[1].remove(rev)

            parents = [p for p in parentsfunc(rev) if p > nullrev]

            gr[1].update(parents)

            for p in parents:

                if p not in pendingset:

                    pendingset.add(p)

                    heappush(pendingheap, -p)

            # Look for a subgroup to display

            #

            # When unblocked is empty (if clause), We are not waiting over any

            # revision during the first iteration (if no priority was given) or

            # if we outputed a whole disconnected sets of the graph (reached a

            # root).  In that case we arbitrarily takes the oldest known

            # subgroup. The heuristique could probably be better.

            #

            # Otherwise (elif clause) this mean we have some emitted revision.

            # if the subgroup awaits on the same revision that the outputed

            # ones, we can safely output it.

            if not unblocked:

                if len(groups) > 1:  # display other subset

                    targetidx = 1

                    gr = groups[1]

            elif not gr[1] & unblocked:

                gr = None

            if gr is not None:

                # update the set of awaited revisions with the one from the

                # subgroup

                unblocked |= gr[1]

                # output all revisions in the subgroup

                for r in gr[0]:

                    yield r

                # delete the subgroup that you just output

                # unless it is groups[0] in which case you just empty it.

                if targetidx:

                    del groups[targetidx]

                else:

                    gr[0][:] = []

    # Check if we have some subgroup waiting for revision we are not going to

    # iterate over

    for g in groups:

        for r in g[0]:

            yield r

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 = revs.min()

    gpcache = {}

    if repo.ui.configbool('experimental', 'graph-topological', False):

    for rev in revs:

        ctx = repo[rev]

        parents = sorted(set([p.rev() for p in ctx.parents()

                              if p.rev() in revs]))

        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 if p != nullrev]

    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