annotate mercurial/graphmod.py @ 46150:a132aa5979ec

copies: no longer cache the ChangedFiles during copy tracing

Now that the copies information for both parents are processed all at once, we
no longer needs to cache this information, so we simplify the code.


The simpler code is also a (tiny) bit faster overall.

Repo            Case                                  Source-Rev   Dest-Rev      # of revisions  old time    new time      Difference    Factor    time per rev
---------------------------------------------------------------------------------------------------------------------------------------------------------------
mercurial       x_revs_x_added_0_copies               ad6b123de1c7 39cfcef4f463 :      1 revs,   0.000041 s,   0.000041 s,  +0.000000 s, × 1.0000,    41 µs/rev
mercurial       x_revs_x_added_x_copies               2b1c78674230 0c1d10351869 :      6 revs,   0.000102 s,   0.000096 s,  -0.000006 s, × 0.9412,    16 µs/rev
mercurial       x000_revs_x000_added_x_copies         81f8ff2a9bf2 dd3267698d84 :   1032 revs,   0.004254 s,   0.004039 s,  -0.000215 s, × 0.9495,     3 µs/rev
pypy            x_revs_x_added_0_copies               aed021ee8ae8 099ed31b181b :      9 revs,   0.000282 s,   0.000189 s,  -0.000093 s, × 0.6702,    21 µs/rev
pypy            x_revs_x000_added_0_copies            4aa4e1f8e19a 359343b9ac0e :      1 revs,   0.000048 s,   0.000047 s,  -0.000001 s, × 0.9792,    47 µs/rev
pypy            x_revs_x_added_x_copies               ac52eb7bbbb0 72e022663155 :      7 revs,   0.000211 s,   0.000103 s,  -0.000108 s, × 0.4882,    14 µs/rev
pypy            x_revs_x00_added_x_copies             c3b14617fbd7 ace7255d9a26 :      1 revs,   0.000375 s,   0.000286 s,  -0.000089 s, × 0.7627,   286 µs/rev
pypy            x_revs_x000_added_x000_copies         df6f7a526b60 a83dc6a2d56f :      6 revs,   0.010574 s,   0.010436 s,  -0.000138 s, × 0.9869,  1739 µs/rev
pypy            x000_revs_xx00_added_0_copies         89a76aede314 2f22446ff07e :   4785 revs,   0.049974 s,   0.047465 s,  -0.002509 s, × 0.9498,     9 µs/rev
pypy            x000_revs_x000_added_x_copies         8a3b5bfd266e 2c68e87c3efe :   6780 revs,   0.084300 s,   0.082351 s,  -0.001949 s, × 0.9769,    12 µs/rev
pypy            x000_revs_x000_added_x000_copies      89a76aede314 7b3dda341c84 :   5441 revs,   0.060128 s,   0.058757 s,  -0.001371 s, × 0.9772,    10 µs/rev
pypy            x0000_revs_x_added_0_copies           d1defd0dc478 c9cb1334cc78 :  43645 revs,   0.686542 s,   0.674129 s,  -0.012413 s, × 0.9819,    15 µs/rev
pypy            x0000_revs_xx000_added_0_copies       bf2c629d0071 4ffed77c095c :      2 revs,   0.009277 s,   0.009434 s,  +0.000157 s, × 1.0169,  4717 µs/rev
pypy            x0000_revs_xx000_added_x000_copies    08ea3258278e d9fa043f30c0 :  11316 revs,   0.114733 s,   0.111935 s,  -0.002798 s, × 0.9756,     9 µs/rev
netbeans        x_revs_x_added_0_copies               fb0955ffcbcd a01e9239f9e7 :      2 revs,   0.000081 s,   0.000078 s,  -0.000003 s, × 0.9630,    39 µs/rev
netbeans        x_revs_x000_added_0_copies            6f360122949f 20eb231cc7d0 :      2 revs,   0.000107 s,   0.000106 s,  -0.000001 s, × 0.9907,    53 µs/rev
netbeans        x_revs_x_added_x_copies               1ada3faf6fb6 5a39d12eecf4 :      3 revs,   0.000173 s,   0.000162 s,  -0.000011 s, × 0.9364,    54 µs/rev
netbeans        x_revs_x00_added_x_copies             35be93ba1e2c 9eec5e90c05f :      9 revs,   0.000698 s,   0.000695 s,  -0.000003 s, × 0.9957,    77 µs/rev
netbeans        x000_revs_xx00_added_0_copies         eac3045b4fdd 51d4ae7f1290 :   1421 revs,   0.009248 s,   0.008901 s,  -0.000347 s, × 0.9625,     6 µs/rev
netbeans        x000_revs_x000_added_x_copies         e2063d266acd 6081d72689dc :   1533 revs,   0.015446 s,   0.014333 s,  -0.001113 s, × 0.9279,     9 µs/rev
netbeans        x000_revs_x000_added_x000_copies      ff453e9fee32 411350406ec2 :   5750 revs,   0.074373 s,   0.071998 s,  -0.002375 s, × 0.9681,    12 µs/rev
netbeans        x0000_revs_xx000_added_x000_copies    588c2d1ced70 1aad62e59ddd :  66949 revs,   0.639870 s,   0.615346 s,  -0.024524 s, × 0.9617,     9 µs/rev
mozilla-central x_revs_x_added_0_copies               3697f962bb7b 7015fcdd43a2 :      2 revs,   0.000088 s,   0.000085 s,  -0.000003 s, × 0.9659,    42 µs/rev
mozilla-central x_revs_x000_added_0_copies            dd390860c6c9 40d0c5bed75d :      8 revs,   0.000199 s,   0.000199 s,  +0.000000 s, × 1.0000,    24 µs/rev
mozilla-central x_revs_x_added_x_copies               8d198483ae3b 14207ffc2b2f :      9 revs,   0.000171 s,   0.000169 s,  -0.000002 s, × 0.9883,    18 µs/rev
mozilla-central x_revs_x00_added_x_copies             98cbc58cc6bc 446a150332c3 :      7 revs,   0.000592 s,   0.000590 s,  -0.000002 s, × 0.9966,    84 µs/rev
mozilla-central x_revs_x000_added_x000_copies         3c684b4b8f68 0a5e72d1b479 :      3 revs,   0.003151 s,   0.003122 s,  -0.000029 s, × 0.9908,  1040 µs/rev
mozilla-central x_revs_x0000_added_x0000_copies       effb563bb7e5 c07a39dc4e80 :      6 revs,   0.061612 s,   0.061192 s,  -0.000420 s, × 0.9932, 10198 µs/rev
mozilla-central x000_revs_xx00_added_0_copies         6100d773079a 04a55431795e :   1593 revs,   0.005381 s,   0.005137 s,  -0.000244 s, × 0.9547,     3 µs/rev
mozilla-central x000_revs_x000_added_x_copies         9f17a6fc04f9 2d37b966abed :     41 revs,   0.003742 s,   0.003585 s,  -0.000157 s, × 0.9580,    87 µs/rev
mozilla-central x000_revs_x000_added_x000_copies      7c97034feb78 4407bd0c6330 :   7839 revs,   0.061983 s,   0.060592 s,  -0.001391 s, × 0.9776,     7 µs/rev
mozilla-central x0000_revs_xx000_added_0_copies       9eec5917337d 67118cc6dcad :    615 revs,   0.019861 s,   0.019596 s,  -0.000265 s, × 0.9867,    31 µs/rev
mozilla-central x0000_revs_xx000_added_x000_copies    f78c615a656c 96a38b690156 :  30263 revs,   0.188101 s,   0.183558 s,  -0.004543 s, × 0.9758,     6 µs/rev
mozilla-central x00000_revs_x0000_added_x0000_copies  6832ae71433c 4c222a1d9a00 : 153721 revs,   1.806696 s,   1.758083 s,  -0.048613 s, × 0.9731,    11 µs/rev
mozilla-central x00000_revs_x00000_added_x000_copies  76caed42cf7c 1daa622bbe42 : 204976 revs,   2.682987 s,   2.592955 s,  -0.090032 s, × 0.9664,    12 µs/rev
mozilla-try     x_revs_x_added_0_copies               aaf6dde0deb8 9790f499805a :      2 revs,   0.000852 s,   0.000844 s,  -0.000008 s, × 0.9906,   422 µs/rev
mozilla-try     x_revs_x000_added_0_copies            d8d0222927b4 5bb8ce8c7450 :      2 revs,   0.000859 s,   0.000861 s,  +0.000002 s, × 1.0023,   430 µs/rev
mozilla-try     x_revs_x_added_x_copies               092fcca11bdb 936255a0384a :      4 revs,   0.000150 s,   0.000150 s,  +0.000000 s, × 1.0000,    37 µs/rev
mozilla-try     x_revs_x00_added_x_copies             b53d2fadbdb5 017afae788ec :      2 revs,   0.001158 s,   0.001166 s,  +0.000008 s, × 1.0069,   583 µs/rev
mozilla-try     x_revs_x000_added_x000_copies         20408ad61ce5 6f0ee96e21ad :      1 revs,   0.027240 s,   0.027359 s,  +0.000119 s, × 1.0044, 27359 µs/rev
mozilla-try     x_revs_x0000_added_x0000_copies       effb563bb7e5 c07a39dc4e80 :      6 revs,   0.062824 s,   0.061848 s,  -0.000976 s, × 0.9845, 10308 µs/rev
mozilla-try     x000_revs_xx00_added_0_copies         6100d773079a 04a55431795e :   1593 revs,   0.005463 s,   0.005110 s,  -0.000353 s, × 0.9354,     3 µs/rev
mozilla-try     x000_revs_x000_added_x_copies         9f17a6fc04f9 2d37b966abed :     41 revs,   0.004238 s,   0.004168 s,  -0.000070 s, × 0.9835,   101 µs/rev
mozilla-try     x000_revs_x000_added_x000_copies      1346fd0130e4 4c65cbdabc1f :   6657 revs,   0.064113 s,   0.063414 s,  -0.000699 s, × 0.9891,     9 µs/rev
mozilla-try     x0000_revs_x_added_0_copies           63519bfd42ee a36a2a865d92 :  40314 revs,   0.294063 s,   0.288301 s,  -0.005762 s, × 0.9804,     7 µs/rev
mozilla-try     x0000_revs_x_added_x_copies           9fe69ff0762d bcabf2a78927 :  38690 revs,   0.281493 s,   0.275798 s,  -0.005695 s, × 0.9798,     7 µs/rev
mozilla-try     x0000_revs_xx000_added_x_copies       156f6e2674f2 4d0f2c178e66 :   8598 revs,   0.076323 s,   0.074640 s,  -0.001683 s, × 0.9779,     8 µs/rev
mozilla-try     x0000_revs_xx000_added_0_copies       9eec5917337d 67118cc6dcad :    615 revs,   0.020390 s,   0.020327 s,  -0.000063 s, × 0.9969,    33 µs/rev
mozilla-try     x0000_revs_xx000_added_x000_copies    89294cd501d9 7ccb2fc7ccb5 :  97052 revs,   3.023879 s,   2.970385 s,  -0.053494 s, × 0.9823,    30 µs/rev
mozilla-try     x0000_revs_x0000_added_x0000_copies   e928c65095ed e951f4ad123a :  52031 revs,   0.735549 s,   0.719432 s,  -0.016117 s, × 0.9781,    13 µs/rev
mozilla-try     x00000_revs_x_added_0_copies          6a320851d377 1ebb79acd503 : 363753 revs,  18.568900 s,  18.165143 s,  -0.403757 s, × 0.9783,    49 µs/rev
mozilla-try     x00000_revs_x00000_added_0_copies     dc8a3ca7010e d16fde900c9c :  34414 revs,   0.502584 s,   0.486769 s,  -0.015815 s, × 0.9685,    14 µs/rev
mozilla-try     x00000_revs_x_added_x_copies          5173c4b6f97c 95d83ee7242d : 362229 revs,  18.356645 s,  17.913924 s,  -0.442721 s, × 0.9759,    49 µs/rev
mozilla-try     x00000_revs_x000_added_x_copies       9126823d0e9c ca82787bb23c : 359344 revs,  18.250393 s,  17.660113 s,  -0.590280 s, × 0.9677,    49 µs/rev
mozilla-try     x00000_revs_x0000_added_x0000_copies  8d3fafa80d4b eb884023b810 : 192665 revs,   2.792459 s,   2.709446 s,  -0.083013 s, × 0.9703,    14 µs/rev
mozilla-try     x00000_revs_x00000_added_x0000_copies 1b661134e2ca 1ae03d022d6d : 228985 revs, 107.697264 s, 107.796891 s,  +0.099627 s, × 1.0009,   470 µs/rev
mozilla-try     x00000_revs_x00000_added_x000_copies  9b2a99adc05e 8e29777b48e6 : 382065 revs,  63.961040 s,  63.575217 s,  -0.385823 s, × 0.9940,   166 µs/rev

Differential Revision: https://phab.mercurial-scm.org/D9423

# 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 __future__ import absolute_import

from .node import nullrev
from .thirdparty import attr
from . import (
    dagop,
    pycompat,
    smartset,
    util,
)

CHANGESET = b'C'
PARENT = b'P'
GRANDPARENT = b'G'
MISSINGPARENT = b'M'
# Style of line to draw. None signals a line that ends and is removed at this
# point. A number prefix means only the last N characters of the current block
# will use that style, the rest will use the PARENT style. Add a - sign
# (so making N negative) and all but the first N characters use that style.
EDGES = {PARENT: b'|', GRANDPARENT: b':', MISSINGPARENT: None}


def dagwalker(repo, revs):
    """cset DAG generator yielding (id, CHANGESET, ctx, [parentinfo]) tuples

    This generator function walks through revisions (which should be ordered
    from bigger to lower). It returns a tuple for each node.

    Each parentinfo entry is a tuple with (edgetype, parentid), where edgetype
    is one of PARENT, GRANDPARENT or MISSINGPARENT. The node and parent ids
    are arbitrary integers which identify a node in the context of the graph
    returned.

    """
    gpcache = {}

    for rev in revs:
        ctx = repo[rev]
        # partition into parents in the rev set and missing parents, then
        # augment the lists with markers, to inform graph drawing code about
        # what kind of edge to draw between nodes.
        pset = {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 pset
        ]
        parents = [(PARENT, p) for p in sorted(pset)]

        for mpar in mpars:
            gp = gpcache.get(mpar)
            if gp is None:
                # precompute slow query as we know reachableroots() goes
                # through all revs (issue4782)
                if not isinstance(revs, smartset.baseset):
                    revs = smartset.baseset(revs)
                gp = gpcache[mpar] = sorted(
                    set(dagop.reachableroots(repo, revs, [mpar]))
                )
            if not gp:
                parents.append((MISSINGPARENT, mpar))
                pset.add(mpar)
            else:
                parents.extend((GRANDPARENT, g) for g in gp if g not in pset)
                pset.update(gp)

        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 = {
            (PARENT, 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(b'graph'):
        if b'.' in key:
            branch, setting = key.rsplit(b'.', 1)
            # Validation
            if setting == b"width" and val.isdigit():
                config.setdefault(branch, {})[setting] = int(val)
            elif setting == b"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 pt, 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(b'width', -1),
                        bconf.get(b'color', b''),
                    )
                )
            elif eid == cur:
                for ptype, p in parents:
                    bconf = getconf(p)
                    edges.append(
                        (
                            ecol,
                            next.index(p),
                            color,
                            bconf.get(b'width', -1),
                            bconf.get(b'color', b''),
                        )
                    )

        # Yield and move on
        yield (cur, type, data, (col, color), edges)
        seen = next


def asciiedges(type, char, state, rev, parents):
    """adds edge info to changelog DAG walk suitable for ascii()"""
    seen = state.seen
    if rev not in seen:
        seen.append(rev)
    nodeidx = seen.index(rev)

    knownparents = []
    newparents = []
    for ptype, parent in parents:
        if parent == rev:
            # self reference (should only be seen in null rev)
            continue
        if parent in seen:
            knownparents.append(parent)
        else:
            newparents.append(parent)
            state.edges[parent] = state.styles.get(ptype, b'|')

    ncols = len(seen)
    width = 1 + ncols * 2
    nextseen = seen[:]
    nextseen[nodeidx : nodeidx + 1] = newparents
    edges = [(nodeidx, nextseen.index(p)) for p in knownparents]

    seen[:] = nextseen
    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
        width += 2
        yield (type, char, width, (nodeidx, edges, ncols, nmorecols))
        char = b'\\'
        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
    if nmorecols > 0:
        width += 2
    # remove current node from edge characters, no longer needed
    state.edges.pop(rev, None)
    yield (type, char, width, (nodeidx, edges, ncols, nmorecols))


def _fixlongrightedges(edges):
    for (i, (start, end)) in enumerate(edges):
        if end > start:
            edges[i] = (start, end + 1)


def _getnodelineedgestail(echars, idx, pidx, ncols, coldiff, pdiff, fix_tail):
    if fix_tail and coldiff == pdiff and coldiff != 0:
        # Still going in the same non-vertical direction.
        if coldiff == -1:
            start = max(idx + 1, pidx)
            tail = echars[idx * 2 : (start - 1) * 2]
            tail.extend([b"/", b" "] * (ncols - start))
            return tail
        else:
            return [b"\\", b" "] * (ncols - idx - 1)
    else:
        remainder = ncols - idx - 1
        return echars[-(remainder * 2) :] if remainder > 0 else []


def _drawedges(echars, edges, nodeline, interline):
    for (start, end) in edges:
        if start == end + 1:
            interline[2 * end + 1] = b"/"
        elif start == end - 1:
            interline[2 * start + 1] = b"\\"
        elif start == end:
            interline[2 * start] = echars[2 * start]
        else:
            if 2 * end >= len(nodeline):
                continue
            nodeline[2 * end] = b"+"
            if start > end:
                (start, end) = (end, start)
            for i in range(2 * start + 1, 2 * end):
                if nodeline[i] != b"+":
                    nodeline[i] = b"-"


def _getpaddingline(echars, idx, ncols, edges):
    # all edges up to the current node
    line = echars[: idx * 2]
    # an edge for the current node, if there is one
    if (idx, idx - 1) in edges or (idx, idx) in edges:
        # (idx, idx - 1)      (idx, idx)
        # | | | |           | | | |
        # +---o |           | o---+
        # | | X |           | X | |
        # | |/ /            | |/ /
        # | | |             | | |
        line.extend(echars[idx * 2 : (idx + 1) * 2])
    else:
        line.extend([b' ', b' '])
    # all edges to the right of the current node
    remainder = ncols - idx - 1
    if remainder > 0:
        line.extend(echars[-(remainder * 2) :])
    return line


def _drawendinglines(lines, extra, edgemap, seen, state):
    """Draw ending lines for missing parent edges

    None indicates an edge that ends at between this node and the next
    Replace with a short line ending in ~ and add / lines to any edges to
    the right.

    """
    if None not in edgemap.values():
        return

    # Check for more edges to the right of our ending edges.
    # We need enough space to draw adjustment lines for these.
    edgechars = extra[::2]
    while edgechars and edgechars[-1] is None:
        edgechars.pop()
    shift_size = max((edgechars.count(None) * 2) - 1, 0)
    minlines = 3 if not state.graphshorten else 2
    while len(lines) < minlines + shift_size:
        lines.append(extra[:])

    if shift_size:
        empties = []
        toshift = []
        first_empty = extra.index(None)
        for i, c in enumerate(extra[first_empty::2], first_empty // 2):
            if c is None:
                empties.append(i * 2)
            else:
                toshift.append(i * 2)
        targets = list(range(first_empty, first_empty + len(toshift) * 2, 2))
        positions = toshift[:]
        for line in lines[-shift_size:]:
            line[first_empty:] = [b' '] * (len(line) - first_empty)
            for i in range(len(positions)):
                pos = positions[i] - 1
                positions[i] = max(pos, targets[i])
                line[pos] = b'/' if pos > targets[i] else extra[toshift[i]]

    map = {1: b'|', 2: b'~'} if not state.graphshorten else {1: b'~'}
    for i, line in enumerate(lines):
        if None not in line:
            continue
        line[:] = [c or map.get(i, b' ') for c in line]

    # remove edges that ended
    remove = [p for p, c in edgemap.items() if c is None]
    for parent in remove:
        del edgemap[parent]
        seen.remove(parent)


@attr.s
class asciistate(object):
    """State of ascii() graph rendering"""

    seen = attr.ib(init=False, default=attr.Factory(list))
    edges = attr.ib(init=False, default=attr.Factory(dict))
    lastcoldiff = attr.ib(init=False, default=0)
    lastindex = attr.ib(init=False, default=0)
    styles = attr.ib(init=False, default=attr.Factory(EDGES.copy))
    graphshorten = attr.ib(init=False, default=False)


def outputgraph(ui, graph):
    """outputs an ASCII graph of a DAG

    this is a helper function for 'ascii' below.

    takes the following arguments:

    - ui to write to
    - graph data: list of { graph nodes/edges, text }

    this function can be monkey-patched by extensions to alter graph display
    without needing to mimic all of the edge-fixup logic in ascii()
    """
    for (ln, logstr) in graph:
        ui.write((ln + logstr).rstrip() + b"\n")


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

    edgemap, seen = state.edges, state.seen
    # Be tolerant of history issues; make sure we have at least ncols + coldiff
    # elements to work with. See test-glog.t for broken history test cases.
    echars = [c for p in seen for c in (edgemap.get(p, b'|'), b' ')]
    echars.extend((b'|', b' ') * max(ncols + coldiff - len(seen), 0))

    if coldiff == -1:
        # Transform
        #
        #     | | |        | | |
        #     o | |  into  o---+
        #     |X /         |/ /
        #     | |          | |
        _fixlongrightedges(edges)

    # add_padding_line says whether to rewrite
    #
    #     | | | |        | | | |
    #     | o---+  into  | o---+
    #     |  / /         |   | |  # <--- padding line
    #     o | |          |  / /
    #                    o | |
    add_padding_line = (
        len(text) > 2 and coldiff == -1 and [x for (x, y) in edges if x + 1 < y]
    )

    # fix_nodeline_tail says whether to rewrite
    #
    #     | | o | |        | | o | |
    #     | | |/ /         | | |/ /
    #     | o | |    into  | o / /   # <--- fixed nodeline tail
    #     | |/ /           | |/ /
    #     o | |            o | |
    fix_nodeline_tail = len(text) <= 2 and not add_padding_line

    # nodeline is the line containing the node character (typically o)
    nodeline = echars[: idx * 2]
    nodeline.extend([char, b" "])

    nodeline.extend(
        _getnodelineedgestail(
            echars,
            idx,
            state.lastindex,
            ncols,
            coldiff,
            state.lastcoldiff,
            fix_nodeline_tail,
        )
    )

    # shift_interline is the line containing the non-vertical
    # edges between this entry and the next
    shift_interline = echars[: idx * 2]
    for i in pycompat.xrange(2 + coldiff):
        shift_interline.append(b' ')
    count = ncols - idx - 1
    if coldiff == -1:
        for i in pycompat.xrange(count):
            shift_interline.extend([b'/', b' '])
    elif coldiff == 0:
        shift_interline.extend(echars[(idx + 1) * 2 : ncols * 2])
    else:
        for i in pycompat.xrange(count):
            shift_interline.extend([b'\\', b' '])

    # draw edges from the current node to its parents
    _drawedges(echars, edges, nodeline, shift_interline)

    # lines is the list of all graph lines to print
    lines = [nodeline]
    if add_padding_line:
        lines.append(_getpaddingline(echars, idx, ncols, edges))

    # If 'graphshorten' config, only draw shift_interline
    # when there is any non vertical flow in graph.
    if state.graphshorten:
        if any(c in br'\/' for c in shift_interline if c):
            lines.append(shift_interline)
    # Else, no 'graphshorten' config so draw shift_interline.
    else:
        lines.append(shift_interline)

    # make sure that there are as many graph lines as there are
    # log strings
    extra_interline = echars[: (ncols + coldiff) * 2]
    if len(lines) < len(text):
        while len(lines) < len(text):
            lines.append(extra_interline[:])

    _drawendinglines(lines, extra_interline, edgemap, seen, state)

    while len(text) < len(lines):
        text.append(b"")

    # print lines
    indentation_level = max(ncols, ncols + coldiff)
    lines = [
        b"%-*s " % (2 * indentation_level, b"".join(line)) for line in lines
    ]
    outputgraph(ui, zip(lines, text))

    # ... and start over
    state.lastcoldiff = coldiff
    state.lastindex = idx