view mercurial/graphmod.py @ 31765:264baeef3588

show: new extension for displaying various repository data Currently, Mercurial has a number of commands to show information. And, there are features coming down the pipe that will introduce more commands for showing information. Currently, when introducing a new class of data or a view that we wish to expose to the user, the strategy is to introduce a new command or overload an existing command, sometimes both. For example, there is a desire to formalize the wip/smartlog/underway/mine functionality that many have devised. There is also a desire to introduce a "topics" concept. Others would like views of "the current stack." In the current model, we'd need a new command for wip/smartlog/etc (that behaves a lot like a pre-defined alias of `hg log`). For topics, we'd likely overload `hg topic[s]` to both display and manipulate topics. Adding new commands for every pre-defined query doesn't scale well and pollutes `hg help`. Overloading commands to perform read-only and write operations is arguably an UX anti-pattern: while having all functionality for a given concept in one command is nice, having a single command doing multiple discrete operations is not. Furthermore, a user may be surprised that a command they thought was read-only actually changes something. We discussed this at the Mercurial 4.0 Sprint in Paris and decided that having a single command where we could hang pre-defined views of various data would be a good idea. Having such a command would: * Help prevent an explosion of new query-related commands * Create a clear separation between read and write operations (mitigates footguns) * Avoids overloading the meaning of commands that manipulate data (bookmark, tag, branch, etc) (while we can't take away the existing behavior for BC reasons, we now won't introduce this behavior on new commands) * Allows users to discover informational views more easily by aggregating them in a single location * Lowers the barrier to creating the new views (since the barrier to creating a top-level command is relatively high) So, this commit introduces the `hg show` command via the "show" extension. This command accepts a positional argument of the "view" to show. New views can be registered with a decorator. To prove it works, we implement the "bookmarks" view, which shows a table of bookmarks and their associated nodes. We introduce a new style to hold everything used by `hg show`. For our initial bookmarks view, the output varies from `hg bookmarks`: * Padding is performed in the template itself as opposed to Python * Revision integers are not shown * shortest() is used to display a 5 character node by default (as opposed to static 12 characters) I chose to implement the "bookmarks" view first because it is simple and shouldn't invite too much bikeshedding that detracts from the evaluation of `hg show` itself. But there is an important point to consider: we now have 2 ways to show a list of bookmarks. I'm not a fan of introducing multiple ways to do very similar things. So it might be worth discussing how we wish to tackle this issue for bookmarks, tags, branches, MQ series, etc. I also made the choice of explicitly declaring the default show template not part of the standard BC guarantees. History has shown that we make mistakes and poor choices with output formatting but can't fix these mistakes later because random tools are parsing output and we don't want to break these tools. Optimizing for human consumption is one of my goals for `hg show`. So, by not covering the formatting as part of BC, the barrier to future change is much lower and humans benefit. There are some improvements that can be made to formatting. For example, we don't yet use label() in the templates. We obviously want this for color. But I'm not sure if we should reuse the existing log.* labels or invent new ones. I figure we can punt that to a follow-up. At the aforementioned Sprint, we discussed and discarded various alternatives to `hg show`. We considered making `hg log <view>` perform this behavior. The main reason we can't do this is because a positional argument to `hg log` can be a file path and if there is a conflict between a path name and a view name, behavior is ambiguous. We could have introduced `hg log --view` or similar, but we felt that required too much typing (we don't want to require a command flag to show a view) and wasn't very discoverable. Furthermore, `hg log` is optimized for showing changelog data and there are things that `hg display` could display that aren't changelog centric. There were concerns about using "show" as the command name. Some users already have a "show" alias that is similar to `hg export`. There were also concerns that Git users adapted to `git show` would be confused by `hg show`'s different behavior. The main difference here is `git show` prints an `hg export` like view of the current commit by default and `hg show` requires an argument. `git show` can also display any Git object. `git show` does not support displaying more complex views: just single objects. If we implemented `hg show <hash>` or `hg show <identifier>`, `hg show` would be a superset of `git show`. Although, I'm hesitant to do that at this time because I view `hg show` as a higher-level querying command and there are namespace collisions between valid identifiers and registered views. There is also a prefix collision with `hg showconfig`, which is an alias of `hg config`. We also considered `hg view`, but that is already used by the "hgk" extension. `hg display` was also proposed at one point. It has a prefix collision with `hg diff`. General consensus was "show" or "view" are the best verbs. And since "view" was taken, "show" was chosen. There are a number of inline TODOs in this patch. Some of these represent decisions yet to be made. Others represent features requiring non-trivial complexity. Rather than bloat the patch or invite additional bikeshedding, I figured I'd document future enhancements via TODO so we can get a minimal implmentation landed. Something is better than nothing.
author Gregory Szorc <gregory.szorc@gmail.com>
date Fri, 24 Mar 2017 19:19:00 -0700
parents d0b9e9803caf
children 906da89821ce
line wrap: on
line source

# 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 __future__ import absolute_import

from .node import nullrev
from . import (
    revset,
    smartset,
    util,
)

CHANGESET = 'C'
PARENT = 'P'
GRANDPARENT = 'G'
MISSINGPARENT = '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: '|', GRANDPARENT: ':', 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.

    """
    if not revs:
        return

    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 = 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 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(revset.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 = set((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('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 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('width', -1),
                    bconf.get('color', '')))
            elif eid == cur:
                for ptype, 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 asciiedges(type, char, lines, 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, '|')

    ncols = len(seen)
    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
        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
    # remove current node from edge characters, no longer needed
    state['edges'].pop(rev, None)
    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(
        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(["/", " "] * (ncols - start))
            return tail
        else:
            return ["\\", " "] * (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] = "/"
        elif start == end - 1:
            interline[2 * start + 1] = "\\"
        elif start == end:
            interline[2 * start] = echars[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(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('  ')
    # 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):
    """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)
    while len(lines) < 3 + 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:] = [' '] * (len(line) - first_empty)
            for i in range(len(positions)):
                pos = positions[i] - 1
                positions[i] = max(pos, targets[i])
                line[pos] = '/' if pos > targets[i] else extra[toshift[i]]

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

def asciistate():
    """returns the initial value for the "state" argument to ascii()"""
    return {
        'seen': [],
        'edges': {},
        'lastcoldiff': 0,
        'lastindex': 0,
        'styles': EDGES.copy(),
        'graphshorten': False,
    }

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, '|'), ' ')]
    echars.extend(('|', ' ') * 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, " "])

    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]
    shift_interline.extend(' ' * (2 + coldiff))
    count = ncols - idx - 1
    if coldiff == -1:
        shift_interline.extend('/ ' * count)
    elif coldiff == 0:
        shift_interline.extend(echars[(idx + 1) * 2:ncols * 2])
    else:
        shift_interline.extend(r'\ ' * count)

    # 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 '\/' 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)

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

    if any(len(char) > 1 for char in edgemap.values()):
        # limit drawing an edge to the first or last N lines of the current
        # section the rest of the edge is drawn like a parent line.
        parent = state['styles'][PARENT][-1]
        def _drawgp(char, i):
            # should a grandparent character be drawn for this line?
            if len(char) < 2:
                return True
            num = int(char[:-1])
            # either skip first num lines or take last num lines, based on sign
            return -num <= i if num < 0 else (len(lines) - i) <= num
        for i, line in enumerate(lines):
            line[:] = [c[-1] if _drawgp(c, i) else parent for c in line]
        edgemap.update(
            (e, (c if len(c) < 2 else parent)) for e, c in edgemap.items())

    # print lines
    indentation_level = max(ncols, ncols + coldiff)
    for (line, logstr) in zip(lines, text):
        ln = "%-*s %s" % (2 * indentation_level, "".join(line), logstr)
        ui.write(ln.rstrip() + '\n')

    # ... and start over
    state['lastcoldiff'] = coldiff
    state['lastindex'] = idx