view mercurial/subrepoutil.py @ 37711:65a23cc8e75b

cborutil: implement support for streaming encoding, bytestring decoding

The vendored cbor2 package is... a bit disappointing.

On the encoding side, it insists that you pass it something with
a write() to send data to. That means if you want to emit data to
a generator, you have to construct an e.g. io.BytesIO(), write()
to it, then get the data back out. There can be non-trivial overhead
involved.

The encoder also doesn't support indefinite types - bytestrings, arrays,
and maps that don't have a known length. Again, this is really
unfortunate because it requires you to buffer the entire source and
destination in memory to encode large things.

On the decoding side, it supports reading indefinite length types.
But it buffers them completely before returning. More sadness.

This commit implements "streaming" encoders for various CBOR types.
Encoding emits a generator of hunks. So you can efficiently stream
encoded data elsewhere.

It also implements support for emitting indefinite length bytestrings,
arrays, and maps.

On the decoding side, we only implement support for decoding an
indefinite length bytestring from a file object. It will emit a
generator of raw chunks from the source.

I didn't want to reinvent so many wheels. But profiling the wire
protocol revealed that the overhead of constructing io.BytesIO()
instances to temporarily hold results has a non-trivial overhead.
We're talking >15% of execution time for operations like
"transfer the fulltexts of all files in a revision." So I can
justify this effort.

Fortunately, CBOR is a relatively straightforward format. And we have
a reference implementation in the repo we can test against.

Differential Revision: https://phab.mercurial-scm.org/D3303

# subrepoutil.py - sub-repository operations and substate handling
#
# Copyright 2009-2010 Matt Mackall <[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.

from __future__ import absolute_import

import errno
import os
import posixpath
import re

from .i18n import _
from . import (
    config,
    error,
    filemerge,
    pathutil,
    phases,
    util,
)
from .utils import (
    stringutil,
)

nullstate = ('', '', 'empty')

def state(ctx, ui):
    """return a state dict, mapping subrepo paths configured in .hgsub
    to tuple: (source from .hgsub, revision from .hgsubstate, kind
    (key in types dict))
    """
    p = config.config()
    repo = ctx.repo()
    def read(f, sections=None, remap=None):
        if f in ctx:
            try:
                data = ctx[f].data()
            except IOError as err:
                if err.errno != errno.ENOENT:
                    raise
                # handle missing subrepo spec files as removed
                ui.warn(_("warning: subrepo spec file \'%s\' not found\n") %
                        repo.pathto(f))
                return
            p.parse(f, data, sections, remap, read)
        else:
            raise error.Abort(_("subrepo spec file \'%s\' not found") %
                             repo.pathto(f))
    if '.hgsub' in ctx:
        read('.hgsub')

    for path, src in ui.configitems('subpaths'):
        p.set('subpaths', path, src, ui.configsource('subpaths', path))

    rev = {}
    if '.hgsubstate' in ctx:
        try:
            for i, l in enumerate(ctx['.hgsubstate'].data().splitlines()):
                l = l.lstrip()
                if not l:
                    continue
                try:
                    revision, path = l.split(" ", 1)
                except ValueError:
                    raise error.Abort(_("invalid subrepository revision "
                                       "specifier in \'%s\' line %d")
                                     % (repo.pathto('.hgsubstate'), (i + 1)))
                rev[path] = revision
        except IOError as err:
            if err.errno != errno.ENOENT:
                raise

    def remap(src):
        for pattern, repl in p.items('subpaths'):
            # Turn r'C:\foo\bar' into r'C:\\foo\\bar' since re.sub
            # does a string decode.
            repl = stringutil.escapestr(repl)
            # However, we still want to allow back references to go
            # through unharmed, so we turn r'\\1' into r'\1'. Again,
            # extra escapes are needed because re.sub string decodes.
            repl = re.sub(br'\\\\([0-9]+)', br'\\\1', repl)
            try:
                src = re.sub(pattern, repl, src, 1)
            except re.error as e:
                raise error.Abort(_("bad subrepository pattern in %s: %s")
                                 % (p.source('subpaths', pattern),
                                    stringutil.forcebytestr(e)))
        return src

    state = {}
    for path, src in p[''].items():
        kind = 'hg'
        if src.startswith('['):
            if ']' not in src:
                raise error.Abort(_('missing ] in subrepository source'))
            kind, src = src.split(']', 1)
            kind = kind[1:]
            src = src.lstrip() # strip any extra whitespace after ']'

        if not util.url(src).isabs():
            parent = _abssource(repo, abort=False)
            if parent:
                parent = util.url(parent)
                parent.path = posixpath.join(parent.path or '', src)
                parent.path = posixpath.normpath(parent.path)
                joined = bytes(parent)
                # Remap the full joined path and use it if it changes,
                # else remap the original source.
                remapped = remap(joined)
                if remapped == joined:
                    src = remap(src)
                else:
                    src = remapped

        src = remap(src)
        state[util.pconvert(path)] = (src.strip(), rev.get(path, ''), kind)

    return state

def writestate(repo, state):
    """rewrite .hgsubstate in (outer) repo with these subrepo states"""
    lines = ['%s %s\n' % (state[s][1], s) for s in sorted(state)
                                                if state[s][1] != nullstate[1]]
    repo.wwrite('.hgsubstate', ''.join(lines), '')

def submerge(repo, wctx, mctx, actx, overwrite, labels=None):
    """delegated from merge.applyupdates: merging of .hgsubstate file
    in working context, merging context and ancestor context"""
    if mctx == actx: # backwards?
        actx = wctx.p1()
    s1 = wctx.substate
    s2 = mctx.substate
    sa = actx.substate
    sm = {}

    repo.ui.debug("subrepo merge %s %s %s\n" % (wctx, mctx, actx))

    def debug(s, msg, r=""):
        if r:
            r = "%s:%s:%s" % r
        repo.ui.debug("  subrepo %s: %s %s\n" % (s, msg, r))

    promptssrc = filemerge.partextras(labels)
    for s, l in sorted(s1.iteritems()):
        prompts = None
        a = sa.get(s, nullstate)
        ld = l # local state with possible dirty flag for compares
        if wctx.sub(s).dirty():
            ld = (l[0], l[1] + "+")
        if wctx == actx: # overwrite
            a = ld

        prompts = promptssrc.copy()
        prompts['s'] = s
        if s in s2:
            r = s2[s]
            if ld == r or r == a: # no change or local is newer
                sm[s] = l
                continue
            elif ld == a: # other side changed
                debug(s, "other changed, get", r)
                wctx.sub(s).get(r, overwrite)
                sm[s] = r
            elif ld[0] != r[0]: # sources differ
                prompts['lo'] = l[0]
                prompts['ro'] = r[0]
                if repo.ui.promptchoice(
                    _(' subrepository sources for %(s)s differ\n'
                      'use (l)ocal%(l)s source (%(lo)s)'
                      ' or (r)emote%(o)s source (%(ro)s)?'
                      '$$ &Local $$ &Remote') % prompts, 0):
                    debug(s, "prompt changed, get", r)
                    wctx.sub(s).get(r, overwrite)
                    sm[s] = r
            elif ld[1] == a[1]: # local side is unchanged
                debug(s, "other side changed, get", r)
                wctx.sub(s).get(r, overwrite)
                sm[s] = r
            else:
                debug(s, "both sides changed")
                srepo = wctx.sub(s)
                prompts['sl'] = srepo.shortid(l[1])
                prompts['sr'] = srepo.shortid(r[1])
                option = repo.ui.promptchoice(
                    _(' subrepository %(s)s diverged (local revision: %(sl)s, '
                      'remote revision: %(sr)s)\n'
                      '(M)erge, keep (l)ocal%(l)s or keep (r)emote%(o)s?'
                      '$$ &Merge $$ &Local $$ &Remote')
                    % prompts, 0)
                if option == 0:
                    wctx.sub(s).merge(r)
                    sm[s] = l
                    debug(s, "merge with", r)
                elif option == 1:
                    sm[s] = l
                    debug(s, "keep local subrepo revision", l)
                else:
                    wctx.sub(s).get(r, overwrite)
                    sm[s] = r
                    debug(s, "get remote subrepo revision", r)
        elif ld == a: # remote removed, local unchanged
            debug(s, "remote removed, remove")
            wctx.sub(s).remove()
        elif a == nullstate: # not present in remote or ancestor
            debug(s, "local added, keep")
            sm[s] = l
            continue
        else:
            if repo.ui.promptchoice(
                _(' local%(l)s changed subrepository %(s)s'
                  ' which remote%(o)s removed\n'
                  'use (c)hanged version or (d)elete?'
                  '$$ &Changed $$ &Delete') % prompts, 0):
                debug(s, "prompt remove")
                wctx.sub(s).remove()

    for s, r in sorted(s2.items()):
        prompts = None
        if s in s1:
            continue
        elif s not in sa:
            debug(s, "remote added, get", r)
            mctx.sub(s).get(r)
            sm[s] = r
        elif r != sa[s]:
            prompts = promptssrc.copy()
            prompts['s'] = s
            if repo.ui.promptchoice(
                _(' remote%(o)s changed subrepository %(s)s'
                  ' which local%(l)s removed\n'
                  'use (c)hanged version or (d)elete?'
                  '$$ &Changed $$ &Delete') % prompts, 0) == 0:
                debug(s, "prompt recreate", r)
                mctx.sub(s).get(r)
                sm[s] = r

    # record merged .hgsubstate
    writestate(repo, sm)
    return sm

def precommit(ui, wctx, status, match, force=False):
    """Calculate .hgsubstate changes that should be applied before committing

    Returns (subs, commitsubs, newstate) where
    - subs: changed subrepos (including dirty ones)
    - commitsubs: dirty subrepos which the caller needs to commit recursively
    - newstate: new state dict which the caller must write to .hgsubstate

    This also updates the given status argument.
    """
    subs = []
    commitsubs = set()
    newstate = wctx.substate.copy()

    # only manage subrepos and .hgsubstate if .hgsub is present
    if '.hgsub' in wctx:
        # we'll decide whether to track this ourselves, thanks
        for c in status.modified, status.added, status.removed:
            if '.hgsubstate' in c:
                c.remove('.hgsubstate')

        # compare current state to last committed state
        # build new substate based on last committed state
        oldstate = wctx.p1().substate
        for s in sorted(newstate.keys()):
            if not match(s):
                # ignore working copy, use old state if present
                if s in oldstate:
                    newstate[s] = oldstate[s]
                    continue
                if not force:
                    raise error.Abort(
                        _("commit with new subrepo %s excluded") % s)
            dirtyreason = wctx.sub(s).dirtyreason(True)
            if dirtyreason:
                if not ui.configbool('ui', 'commitsubrepos'):
                    raise error.Abort(dirtyreason,
                        hint=_("use --subrepos for recursive commit"))
                subs.append(s)
                commitsubs.add(s)
            else:
                bs = wctx.sub(s).basestate()
                newstate[s] = (newstate[s][0], bs, newstate[s][2])
                if oldstate.get(s, (None, None, None))[1] != bs:
                    subs.append(s)

        # check for removed subrepos
        for p in wctx.parents():
            r = [s for s in p.substate if s not in newstate]
            subs += [s for s in r if match(s)]
        if subs:
            if (not match('.hgsub') and
                '.hgsub' in (wctx.modified() + wctx.added())):
                raise error.Abort(_("can't commit subrepos without .hgsub"))
            status.modified.insert(0, '.hgsubstate')

    elif '.hgsub' in status.removed:
        # clean up .hgsubstate when .hgsub is removed
        if ('.hgsubstate' in wctx and
            '.hgsubstate' not in (status.modified + status.added +
                                  status.removed)):
            status.removed.insert(0, '.hgsubstate')

    return subs, commitsubs, newstate

def reporelpath(repo):
    """return path to this (sub)repo as seen from outermost repo"""
    parent = repo
    while util.safehasattr(parent, '_subparent'):
        parent = parent._subparent
    return repo.root[len(pathutil.normasprefix(parent.root)):]

def subrelpath(sub):
    """return path to this subrepo as seen from outermost repo"""
    return sub._relpath

def _abssource(repo, push=False, abort=True):
    """return pull/push path of repo - either based on parent repo .hgsub info
    or on the top repo config. Abort or return None if no source found."""
    if util.safehasattr(repo, '_subparent'):
        source = util.url(repo._subsource)
        if source.isabs():
            return bytes(source)
        source.path = posixpath.normpath(source.path)
        parent = _abssource(repo._subparent, push, abort=False)
        if parent:
            parent = util.url(util.pconvert(parent))
            parent.path = posixpath.join(parent.path or '', source.path)
            parent.path = posixpath.normpath(parent.path)
            return bytes(parent)
    else: # recursion reached top repo
        path = None
        if util.safehasattr(repo, '_subtoppath'):
            path = repo._subtoppath
        elif push and repo.ui.config('paths', 'default-push'):
            path = repo.ui.config('paths', 'default-push')
        elif repo.ui.config('paths', 'default'):
            path = repo.ui.config('paths', 'default')
        elif repo.shared():
            # chop off the .hg component to get the default path form.  This has
            # already run through vfsmod.vfs(..., realpath=True), so it doesn't
            # have problems with 'C:'
            return os.path.dirname(repo.sharedpath)
        if path:
            # issue5770: 'C:\' and 'C:' are not equivalent paths.  The former is
            # as expected: an absolute path to the root of the C: drive.  The
            # latter is a relative path, and works like so:
            #
            #   C:\>cd C:\some\path
            #   C:\>D:
            #   D:\>python -c "import os; print os.path.abspath('C:')"
            #   C:\some\path
            #
            #   D:\>python -c "import os; print os.path.abspath('C:relative')"
            #   C:\some\path\relative
            if util.hasdriveletter(path):
                if len(path) == 2 or path[2:3] not in br'\/':
                    path = os.path.abspath(path)
            return path

    if abort:
        raise error.Abort(_("default path for subrepository not found"))

def newcommitphase(ui, ctx):
    commitphase = phases.newcommitphase(ui)
    substate = getattr(ctx, "substate", None)
    if not substate:
        return commitphase
    check = ui.config('phases', 'checksubrepos')
    if check not in ('ignore', 'follow', 'abort'):
        raise error.Abort(_('invalid phases.checksubrepos configuration: %s')
                         % (check))
    if check == 'ignore':
        return commitphase
    maxphase = phases.public
    maxsub = None
    for s in sorted(substate):
        sub = ctx.sub(s)
        subphase = sub.phase(substate[s][1])
        if maxphase < subphase:
            maxphase = subphase
            maxsub = s
    if commitphase < maxphase:
        if check == 'abort':
            raise error.Abort(_("can't commit in %s phase"
                               " conflicting %s from subrepository %s") %
                             (phases.phasenames[commitphase],
                              phases.phasenames[maxphase], maxsub))
        ui.warn(_("warning: changes are committed in"
                  " %s phase from subrepository %s\n") %
                (phases.phasenames[maxphase], maxsub))
        return maxphase
    return commitphase