Mercurial > hg
view mercurial/commandserver.py @ 29304:5e32852fa4bd
revset: make filteredset.__nonzero__ respect the order of the filteredset
This fix allows __nonzero__ to respect the direction of iteration of the
whole filteredset. Here's the case when it matters. Imagine that we have a
very large repository and we want to execute a command like:
$ hg log --rev '(tip:0) and user(ikostia)' --limit 1
(we want to get the latest commit by me).
Mercurial will evaluate a filteredset lazy data structure, an
instance of the filteredset class, which will know that it has to iterate
in a descending order (isdescending() will return True if called). This
means that when some code iterates over the instance of this filteredset,
the 'and user(ikostia)' condition will be first checked on the latest
revision, then on the second latest and so on, allowing Mercurial to
print matches as it founds them. However, cmdutil.getgraphlogrevs
contains the following code:
revs = _logrevs(repo, opts)
if not revs:
return revset.baseset(), None, None
The "not revs" expression is evaluated by calling filteredset.__nonzero__,
which in its current implementation will try to iterate the filteredset
in ascending order until it finds a revision that matches the 'and user(..'
condition. If the condition is only true on late revisions, a lot of
useless iterations will be done. These iterations could be avoided if
__nonzero__ followed the order of the filteredset, which in my opinion
is a sensible thing to do here.
The problem gets even worse when instead of 'user(ikostia)' some more
expensive check is performed, like grepping the commit diff.
I tested this fix on a very large repo where tip is my commit and my very
first commit comes fairly late in the revision history. Results of timing
of the above command on that very large repo.
-with my fix:
real 0m1.795s
user 0m1.657s
sys 0m0.135s
-without my fix:
real 1m29.245s
user 1m28.223s
sys 0m0.929s
I understand that this is a very specific kind of problem that presents
itself very rarely, only on very big repositories and with expensive
checks and so on. But I don't see any disadvantages to this kind of fix
either.
author | Kostia Balytskyi <ikostia@fb.com> |
---|---|
date | Thu, 02 Jun 2016 22:39:01 +0100 |
parents | ff5f923fca3c |
children | d269e7db2f55 |
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# commandserver.py - communicate with Mercurial's API over a pipe # # Copyright Matt Mackall <mpm@selenic.com> # # 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 SocketServer import errno import os import struct import sys import traceback from .i18n import _ from . import ( encoding, error, util, ) logfile = None def log(*args): if not logfile: return for a in args: logfile.write(str(a)) logfile.flush() class channeledoutput(object): """ Write data to out in the following format: data length (unsigned int), data """ def __init__(self, out, channel): self.out = out self.channel = channel @property def name(self): return '<%c-channel>' % self.channel def write(self, data): if not data: return self.out.write(struct.pack('>cI', self.channel, len(data))) self.out.write(data) self.out.flush() def __getattr__(self, attr): if attr in ('isatty', 'fileno', 'tell', 'seek'): raise AttributeError(attr) return getattr(self.out, attr) class channeledinput(object): """ Read data from in_. Requests for input are written to out in the following format: channel identifier - 'I' for plain input, 'L' line based (1 byte) how many bytes to send at most (unsigned int), The client replies with: data length (unsigned int), 0 meaning EOF data """ maxchunksize = 4 * 1024 def __init__(self, in_, out, channel): self.in_ = in_ self.out = out self.channel = channel @property def name(self): return '<%c-channel>' % self.channel def read(self, size=-1): if size < 0: # if we need to consume all the clients input, ask for 4k chunks # so the pipe doesn't fill up risking a deadlock size = self.maxchunksize s = self._read(size, self.channel) buf = s while s: s = self._read(size, self.channel) buf += s return buf else: return self._read(size, self.channel) def _read(self, size, channel): if not size: return '' assert size > 0 # tell the client we need at most size bytes self.out.write(struct.pack('>cI', channel, size)) self.out.flush() length = self.in_.read(4) length = struct.unpack('>I', length)[0] if not length: return '' else: return self.in_.read(length) def readline(self, size=-1): if size < 0: size = self.maxchunksize s = self._read(size, 'L') buf = s # keep asking for more until there's either no more or # we got a full line while s and s[-1] != '\n': s = self._read(size, 'L') buf += s return buf else: return self._read(size, 'L') def __iter__(self): return self def next(self): l = self.readline() if not l: raise StopIteration return l def __getattr__(self, attr): if attr in ('isatty', 'fileno', 'tell', 'seek'): raise AttributeError(attr) return getattr(self.in_, attr) class server(object): """ Listens for commands on fin, runs them and writes the output on a channel based stream to fout. """ def __init__(self, ui, repo, fin, fout): self.cwd = os.getcwd() # developer config: cmdserver.log logpath = ui.config("cmdserver", "log", None) if logpath: global logfile if logpath == '-': # write log on a special 'd' (debug) channel logfile = channeledoutput(fout, 'd') else: logfile = open(logpath, 'a') if repo: # the ui here is really the repo ui so take its baseui so we don't # end up with its local configuration self.ui = repo.baseui self.repo = repo self.repoui = repo.ui else: self.ui = ui self.repo = self.repoui = None self.cerr = channeledoutput(fout, 'e') self.cout = channeledoutput(fout, 'o') self.cin = channeledinput(fin, fout, 'I') self.cresult = channeledoutput(fout, 'r') self.client = fin def _read(self, size): if not size: return '' data = self.client.read(size) # is the other end closed? if not data: raise EOFError return data def _readstr(self): """read a string from the channel format: data length (uint32), data """ length = struct.unpack('>I', self._read(4))[0] if not length: return '' return self._read(length) def _readlist(self): """read a list of NULL separated strings from the channel""" s = self._readstr() if s: return s.split('\0') else: return [] def runcommand(self): """ reads a list of \0 terminated arguments, executes and writes the return code to the result channel """ from . import dispatch # avoid cycle args = self._readlist() # copy the uis so changes (e.g. --config or --verbose) don't # persist between requests copiedui = self.ui.copy() uis = [copiedui] if self.repo: self.repo.baseui = copiedui # clone ui without using ui.copy because this is protected repoui = self.repoui.__class__(self.repoui) repoui.copy = copiedui.copy # redo copy protection uis.append(repoui) self.repo.ui = self.repo.dirstate._ui = repoui self.repo.invalidateall() # reset last-print time of progress bar per command # (progbar is singleton, we don't have to do for all uis) if copiedui._progbar: copiedui._progbar.resetstate() for ui in uis: # any kind of interaction must use server channels, but chg may # replace channels by fully functional tty files. so nontty is # enforced only if cin is a channel. if not util.safehasattr(self.cin, 'fileno'): ui.setconfig('ui', 'nontty', 'true', 'commandserver') req = dispatch.request(args[:], copiedui, self.repo, self.cin, self.cout, self.cerr) ret = (dispatch.dispatch(req) or 0) & 255 # might return None # restore old cwd if '--cwd' in args: os.chdir(self.cwd) self.cresult.write(struct.pack('>i', int(ret))) def getencoding(self): """ writes the current encoding to the result channel """ self.cresult.write(encoding.encoding) def serveone(self): cmd = self.client.readline()[:-1] if cmd: handler = self.capabilities.get(cmd) if handler: handler(self) else: # clients are expected to check what commands are supported by # looking at the servers capabilities raise error.Abort(_('unknown command %s') % cmd) return cmd != '' capabilities = {'runcommand' : runcommand, 'getencoding' : getencoding} def serve(self): hellomsg = 'capabilities: ' + ' '.join(sorted(self.capabilities)) hellomsg += '\n' hellomsg += 'encoding: ' + encoding.encoding hellomsg += '\n' hellomsg += 'pid: %d' % util.getpid() # write the hello msg in -one- chunk self.cout.write(hellomsg) try: while self.serveone(): pass except EOFError: # we'll get here if the client disconnected while we were reading # its request return 1 return 0 def _protectio(ui): """ duplicates streams and redirect original to null if ui uses stdio """ ui.flush() newfiles = [] nullfd = os.open(os.devnull, os.O_RDWR) for f, sysf, mode in [(ui.fin, sys.stdin, 'rb'), (ui.fout, sys.stdout, 'wb')]: if f is sysf: newfd = os.dup(f.fileno()) os.dup2(nullfd, f.fileno()) f = os.fdopen(newfd, mode) newfiles.append(f) os.close(nullfd) return tuple(newfiles) def _restoreio(ui, fin, fout): """ restores streams from duplicated ones """ ui.flush() for f, uif in [(fin, ui.fin), (fout, ui.fout)]: if f is not uif: os.dup2(f.fileno(), uif.fileno()) f.close() class pipeservice(object): def __init__(self, ui, repo, opts): self.ui = ui self.repo = repo def init(self): pass def run(self): ui = self.ui # redirect stdio to null device so that broken extensions or in-process # hooks will never cause corruption of channel protocol. fin, fout = _protectio(ui) try: sv = server(ui, self.repo, fin, fout) return sv.serve() finally: _restoreio(ui, fin, fout) class _requesthandler(SocketServer.StreamRequestHandler): def handle(self): ui = self.server.ui repo = self.server.repo sv = None try: sv = server(ui, repo, self.rfile, self.wfile) try: sv.serve() # handle exceptions that may be raised by command server. most of # known exceptions are caught by dispatch. except error.Abort as inst: ui.warn(_('abort: %s\n') % inst) except IOError as inst: if inst.errno != errno.EPIPE: raise except KeyboardInterrupt: pass except: # re-raises # also write traceback to error channel. otherwise client cannot # see it because it is written to server's stderr by default. if sv: cerr = sv.cerr else: cerr = channeledoutput(self.wfile, 'e') traceback.print_exc(file=cerr) raise class unixservice(object): """ Listens on unix domain socket and forks server per connection """ def __init__(self, ui, repo, opts): self.ui = ui self.repo = repo self.address = opts['address'] if not util.safehasattr(SocketServer, 'UnixStreamServer'): raise error.Abort(_('unsupported platform')) if not self.address: raise error.Abort(_('no socket path specified with --address')) def init(self): class cls(SocketServer.ForkingMixIn, SocketServer.UnixStreamServer): ui = self.ui repo = self.repo self.server = cls(self.address, _requesthandler) self.ui.status(_('listening at %s\n') % self.address) self.ui.flush() # avoid buffering of status message def run(self): try: self.server.serve_forever() finally: os.unlink(self.address) _servicemap = { 'pipe': pipeservice, 'unix': unixservice, } def createservice(ui, repo, opts): mode = opts['cmdserver'] try: return _servicemap[mode](ui, repo, opts) except KeyError: raise error.Abort(_('unknown mode %s') % mode)