view mercurial/subrepoutil.py @ 37051:40206e227412

wireproto: define and implement protocol for issuing requests

The existing HTTP and SSH wire protocols suffer from a host of flaws
and shortcomings. I've been wanting to rewrite the protocol for a while
now. Supporting partial clone - which will require new wire protocol
commands and capabilities - and other advanced server functionality
will be much easier if we start from a clean slate and don't have
to be constrained by limitations of the existing wire protocol.

This commit starts to introduce a new data exchange format for
use over the wire protocol.

The new protocol is built on top of "frames," which are atomic
units of metadata + data. Frames will make it easier to implement
proxies and other mechanisms that want to inspect data without
having to maintain state. The existing frame metadata is very
minimal and it will evolve heavily. (We will eventually support
things like concurrent requests, out-of-order responses,
compression, side-channels for status updates, etc. Some of
these will require additions to the frame header.)

Another benefit of frames is that all reads are of a fixed size.
A reader works by consuming a frame header, extracting the payload
length, then reading that many bytes. No lookahead, buffering, or
memory reallocations are needed.

The new protocol attempts to be transport agnostic. I want all that's
required to use the new protocol to be a pair of unidirectional,
half-duplex pipes. (Yes, we will eventually make use of full-duplex
pipes, but that's for another commit.) Notably, when the SSH
transport switches to this new protocol, stderr will be unused.
This is by design: the lack of stderr on HTTP harms protocol
behavior there. By shoehorning everything into a pair of pipes,
we can have more consistent behavior across transports.

We currently only define the client side parts of the new protocol,
specifically the bits for requesting that a command run. This keeps
the new code and feature small and somewhat easy to review.

We add support to `hg debugwireproto` for writing frames into
HTTP request bodies. Our tests that issue commands to the new
HTTP endpoint have been updated to transmit frames. The server
bits haven't been touched to consume the frames yet. This will
occur in the next commit...

Astute readers may notice that the command name is transmitted in
both the HTTP request URL and the command request frame. This is
partially a kludge from me initially implementing the frame-based
protocol for SSH first. But it is also a feature: I intend to
eventually support issuing multiple commands per HTTP request. This
will allow us to replace the abomination that is the "batch" wire
protocol command with a protocol-level mechanism for performing
multi-dispatch. Because I want the frame-based protocol to be
as similar as possible across transports, I'd rather we (redundantly)
include the command name in the frame than differ behavior between
transports that have out-of-band routing information (like HTTP)
readily available.

Differential Revision: https://phab.mercurial-scm.org/D2851

# 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,
)

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 = util.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), 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 = str(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