comparison mercurial/cmdutil.py @ 45650:0356b41fe01d

cmdutil: rewrite walkchangerevs() by using logcmdutil functions

cmdutil.walkchangerevs() now takes (revs, makefilematcher) in place of
(match, opts), and only provides the "windowing" functionality. Unused
classes and functions will be removed by the next patch.

"hg grep --follow" (--all-files) is still broken since there is no logic
to follow copies while traversing changelog, but at least, it does follow
the DAG.

45649:bba730d7a6f4

                return True

        return False


def walkchangerevs(repo, match, opts, prepare):
    '''Iterate over files and the revs in which they changed.

    Callers most commonly need to iterate backwards over the history
    in which they are interested. Doing so has awful (quadratic-looking)
    performance, so we use iterators in a "windowed" way.

    This function returns an iterator yielding contexts. Before
    yielding each context, the iterator will first call the prepare
    function on each context in the window in forward order.'''

    allfiles = opts.get(b'all_files')
    follow = opts.get(b'follow') or opts.get(b'follow_first')
    revs = _walkrevs(repo, opts)
    if not revs:
        return []
    wanted = set()
    slowpath = match.anypats() or (not match.always() and opts.get(b'removed'))
    fncache = {}
    change = repo.__getitem__

    # First step is to fill wanted, the set of revisions that we want to yield.
    # When it does not induce extra cost, we also fill fncache for revisions in
    # wanted: a cache of filenames that were changed (ctx.files()) and that
    # match the file filtering conditions.

    if match.always() or allfiles:
        # No files, no patterns.  Display all revs.
        wanted = revs
    elif not slowpath:
        # We only have to read through the filelog to find wanted revisions

        try:
            wanted = walkfilerevs(repo, match, follow, revs, fncache)
        except FileWalkError:
            slowpath = True

            # We decided to fall back to the slowpath because at least one
            # of the paths was not a file. Check to see if at least one of them
            # existed in history, otherwise simply return
            for path in match.files():
                if path == b'.' or path in repo.store:
                    break
            else:
                return []

    if slowpath:
        # We have to read the changelog to match filenames against
        # changed files

        if follow:
            raise error.Abort(
                _(b'can only follow copies/renames for explicit filenames')
            )

        # The slow path checks files modified in every changeset.
        # This is really slow on large repos, so compute the set lazily.
        class lazywantedset(object):
            def __init__(self):
                self.set = set()
                self.revs = set(revs)

            # No need to worry about locality here because it will be accessed
            # in the same order as the increasing window below.
            def __contains__(self, value):
                if value in self.set:
                    return True
                elif not value in self.revs:
                    return False
                else:
                    self.revs.discard(value)
                    ctx = change(value)
                    if allfiles:
                        matches = list(ctx.manifest().walk(match))
                    else:
                        matches = [f for f in ctx.files() if match(f)]
                    if matches:
                        fncache[value] = matches
                        self.set.add(value)
                        return True
                    return False

            def discard(self, value):
                self.revs.discard(value)
                self.set.discard(value)

        wanted = lazywantedset()

    # it might be worthwhile to do this in the iterator if the rev range
    # is descending and the prune args are all within that range
    for rev in opts.get(b'prune', ()):
        rev = repo[rev].rev()
        ff = _followfilter(repo)
        stop = min(revs[0], revs[-1])
        for x in pycompat.xrange(rev, stop - 1, -1):
            if ff.match(x):
                wanted = wanted - [x]

    # Now that wanted is correctly initialized, we can iterate over the
    # revision range, yielding only revisions in wanted.
    def iterate():
        if follow and match.always():
            ff = _followfilter(repo, onlyfirst=opts.get(b'follow_first'))

            def want(rev):
                return ff.match(rev) and rev in wanted

        else:

            def want(rev):
                return rev in wanted

        it = iter(revs)
        stopiteration = False
        for windowsize in increasingwindows():
            nrevs = []
            for i in pycompat.xrange(windowsize):
                rev = next(it, None)
                if rev is None:
                    stopiteration = True
                    break
                elif want(rev):
                    nrevs.append(rev)
            for rev in sorted(nrevs):
                fns = fncache.get(rev)
                ctx = change(rev)
                if not fns:

                    def fns_generator():
                        if allfiles:

                            def bad(f, msg):
                                pass

                            for f in ctx.matches(matchmod.badmatch(match, bad)):
                                yield f
                        else:
                            for f in ctx.files():
                                if match(f):
                                    yield f

                    fns = fns_generator()
                prepare(ctx, scmutil.matchfiles(repo, fns))
            for rev in nrevs:
                yield change(rev)

            if stopiteration:
                break

45650:0356b41fe01d

                return True

        return False


def walkchangerevs(repo, revs, makefilematcher, prepare):
    '''Iterate over files and the revs in a "windowed" way.

    Callers most commonly need to iterate backwards over the history
    in which they are interested. Doing so has awful (quadratic-looking)
    performance, so we use iterators in a "windowed" way.

    This function returns an iterator yielding contexts. Before
    yielding each context, the iterator will first call the prepare
    function on each context in the window in forward order.'''

    if not revs:
        return []
    change = repo.__getitem__

    def iterate():
        it = iter(revs)
        stopiteration = False
        for windowsize in increasingwindows():
            nrevs = []
            for i in pycompat.xrange(windowsize):
                rev = next(it, None)
                if rev is None:
                    stopiteration = True
                    break
                nrevs.append(rev)
            for rev in sorted(nrevs):
                ctx = change(rev)
                prepare(ctx, makefilematcher(ctx))
            for rev in nrevs:
                yield change(rev)

            if stopiteration:
                break