view hgext/fastannotate/protocol.py @ 39715:d8a7690ccc74

fastannotate: process files as they arrive

peer.commandexecutor()'s context manager waits for all responses to
arrive in its __exit__() method. We want to process the results as
they arrive, so we should do that inside the context manager
scope. Note that the futures' result() methods have been replaced to
make sure that the command executor's sendcommands() method is called
when the first future's result is requested, so we don't need to do
that.

A minor side-effect is that we can no longer easily tell when the
server has started sending us responses, so that long statement was
lost.

Differential Revision: https://phab.mercurial-scm.org/D4666

# Copyright 2016-present Facebook. All Rights Reserved.
#
# protocol: logic for a server providing fastannotate support
#
# 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 contextlib
import os

from mercurial.i18n import _
from mercurial import (
    error,
    extensions,
    hg,
    util,
    wireprotov1peer,
    wireprotov1server,
)
from . import context

# common

def _getmaster(ui):
    """get the mainbranch, and enforce it is set"""
    master = ui.config('fastannotate', 'mainbranch')
    if not master:
        raise error.Abort(_('fastannotate.mainbranch is required '
                            'for both the client and the server'))
    return master

# server-side

def _capabilities(orig, repo, proto):
    result = orig(repo, proto)
    result.append('getannotate')
    return result

def _getannotate(repo, proto, path, lastnode):
    # output:
    #   FILE := vfspath + '\0' + str(size) + '\0' + content
    #   OUTPUT := '' | FILE + OUTPUT
    result = ''
    buildondemand = repo.ui.configbool('fastannotate', 'serverbuildondemand',
                                       True)
    with context.annotatecontext(repo, path) as actx:
        if buildondemand:
            # update before responding to the client
            master = _getmaster(repo.ui)
            try:
                if not actx.isuptodate(master):
                    actx.annotate(master, master)
            except Exception:
                # non-fast-forward move or corrupted. rebuild automically.
                actx.rebuild()
                try:
                    actx.annotate(master, master)
                except Exception:
                    actx.rebuild() # delete files
            finally:
                # although the "with" context will also do a close/flush, we
                # need to do it early so we can send the correct respond to
                # client.
                actx.close()
        # send back the full content of revmap and linelog, in the future we
        # may want to do some rsync-like fancy updating.
        # the lastnode check is not necessary if the client and the server
        # agree where the main branch is.
        if actx.lastnode != lastnode:
            for p in [actx.revmappath, actx.linelogpath]:
                if not os.path.exists(p):
                    continue
                content = ''
                with open(p, 'rb') as f:
                    content = f.read()
                vfsbaselen = len(repo.vfs.base + '/')
                relpath = p[vfsbaselen:]
                result += '%s\0%d\0%s' % (relpath, len(content), content)
    return result

def _registerwireprotocommand():
    if 'getannotate' in wireprotov1server.commands:
        return
    wireprotov1server.wireprotocommand(
        'getannotate', 'path lastnode')(_getannotate)

def serveruisetup(ui):
    _registerwireprotocommand()
    extensions.wrapfunction(wireprotov1server, '_capabilities', _capabilities)

# client-side

def _parseresponse(payload):
    result = {}
    i = 0
    l = len(payload) - 1
    state = 0 # 0: vfspath, 1: size
    vfspath = size = ''
    while i < l:
        ch = payload[i]
        if ch == '\0':
            if state == 1:
                result[vfspath] = buffer(payload, i + 1, int(size))
                i += int(size)
                state = 0
                vfspath = size = ''
            elif state == 0:
                state = 1
        else:
            if state == 1:
                size += ch
            elif state == 0:
                vfspath += ch
        i += 1
    return result

def peersetup(ui, peer):
    class fastannotatepeer(peer.__class__):
        @wireprotov1peer.batchable
        def getannotate(self, path, lastnode=None):
            if not self.capable('getannotate'):
                ui.warn(_('remote peer cannot provide annotate cache\n'))
                yield None, None
            else:
                args = {'path': path, 'lastnode': lastnode or ''}
                f = wireprotov1peer.future()
                yield args, f
                yield _parseresponse(f.value)
    peer.__class__ = fastannotatepeer

@contextlib.contextmanager
def annotatepeer(repo):
    ui = repo.ui

    remotepath = ui.expandpath(
        ui.config('fastannotate', 'remotepath', 'default'))
    peer = hg.peer(ui, {}, remotepath)

    try:
        yield peer
    finally:
        peer.close()

def clientfetch(repo, paths, lastnodemap=None, peer=None):
    """download annotate cache from the server for paths"""
    if not paths:
        return

    if peer is None:
        with annotatepeer(repo) as peer:
            return clientfetch(repo, paths, lastnodemap, peer)

    if lastnodemap is None:
        lastnodemap = {}

    ui = repo.ui
    results = []
    with peer.commandexecutor() as batcher:
        ui.debug('fastannotate: requesting %d files\n' % len(paths))
        for p in paths:
            results.append(batcher.callcommand(
                'getannotate',
                {'path': p, 'lastnode':lastnodemap.get(p)}))

        for result in results:
            r = result.result()
            # TODO: pconvert these paths on the server?
            r = {util.pconvert(p): v for p, v in r.iteritems()}
            for path in sorted(r):
                # ignore malicious paths
                if (not path.startswith('fastannotate/')
                    or '/../' in (path + '/')):
                    ui.debug('fastannotate: ignored malicious path %s\n' % path)
                    continue
                content = r[path]
                if ui.debugflag:
                    ui.debug('fastannotate: writing %d bytes to %s\n'
                             % (len(content), path))
                repo.vfs.makedirs(os.path.dirname(path))
                with repo.vfs(path, 'wb') as f:
                    f.write(content)

def _filterfetchpaths(repo, paths):
    """return a subset of paths whose history is long and need to fetch linelog
    from the server. works with remotefilelog and non-remotefilelog repos.
    """
    threshold = repo.ui.configint('fastannotate', 'clientfetchthreshold', 10)
    if threshold <= 0:
        return paths

    result = []
    for path in paths:
        try:
            if len(repo.file(path)) >= threshold:
                result.append(path)
        except Exception: # file not found etc.
            result.append(path)

    return result

def localreposetup(ui, repo):
    class fastannotaterepo(repo.__class__):
        def prefetchfastannotate(self, paths, peer=None):
            master = _getmaster(self.ui)
            needupdatepaths = []
            lastnodemap = {}
            try:
                for path in _filterfetchpaths(self, paths):
                    with context.annotatecontext(self, path) as actx:
                        if not actx.isuptodate(master, strict=False):
                            needupdatepaths.append(path)
                            lastnodemap[path] = actx.lastnode
                if needupdatepaths:
                    clientfetch(self, needupdatepaths, lastnodemap, peer)
            except Exception as ex:
                # could be directory not writable or so, not fatal
                self.ui.debug('fastannotate: prefetch failed: %r\n' % ex)
    repo.__class__ = fastannotaterepo

def clientreposetup(ui, repo):
    _registerwireprotocommand()
    if repo.local():
        localreposetup(ui, repo)
    # TODO: this mutates global state, but only if at least one repo
    # has the extension enabled. This is probably bad for hgweb.
    if peersetup not in hg.wirepeersetupfuncs:
        hg.wirepeersetupfuncs.append(peersetup)