mercurial/sshserver.py

dirstate: delay writing out to ensure timestamp of each entries explicitly

Even though "dirstate.write()" is invoked explicitly after "normal"
invocations, timestamp field of entries may be still "unset" in the
"dirstate" file itself , because "pack_dirstate" drops it when it is
equal to the timestamp of "dirstate" file itself.

This can avoid overlooking modification of files, which are updated at
same time in the second. But on the other hand, this may hide timing
critical problems.

For example, incorrect "normal"-ing (or lack of "normallookup"-ing on
the already "normal"-ed entry) is visible only when:

  - the target file is modified in the working directory at T1, and
  - "dirstate" file is written out at T2 (!= T1)

Otherwise, T1 is dropped by "pack_dirstate" in "dirstate.write()"
invocation, and "unset" is stored into "dirstate" file.

It often fails to reproduce problems from incorrect "normal"-ing by
Mercurial testset, because automated actions in the small repository
almost always causes that T1 and T2 are same.

This patch adds the debug feature to delay writing out to ensure
timestamp of each entries explicitly.

This feature is used to make timing critical "dirstate" problems
reproducable in subsequent patches.

# sshserver.py - ssh protocol server support for mercurial
#
# Copyright 2005-2007 Matt Mackall <[e-mail]>
# Copyright 2006 Vadim Gelfer <[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.

import util, hook, wireproto, changegroup
import os, sys

class sshserver(wireproto.abstractserverproto):
    def __init__(self, ui, repo):
        self.ui = ui
        self.repo = repo
        self.lock = None
        self.fin = ui.fin
        self.fout = ui.fout

        hook.redirect(True)
        ui.fout = repo.ui.fout = ui.ferr

        # Prevent insertion/deletion of CRs
        util.setbinary(self.fin)
        util.setbinary(self.fout)

    def getargs(self, args):
        data = {}
        keys = args.split()
        for n in xrange(len(keys)):
            argline = self.fin.readline()[:-1]
            arg, l = argline.split()
            if arg not in keys:
                raise util.Abort("unexpected parameter %r" % arg)
            if arg == '*':
                star = {}
                for k in xrange(int(l)):
                    argline = self.fin.readline()[:-1]
                    arg, l = argline.split()
                    val = self.fin.read(int(l))
                    star[arg] = val
                data['*'] = star
            else:
                val = self.fin.read(int(l))
                data[arg] = val
        return [data[k] for k in keys]

    def getarg(self, name):
        return self.getargs(name)[0]

    def getfile(self, fpout):
        self.sendresponse('')
        count = int(self.fin.readline())
        while count:
            fpout.write(self.fin.read(count))
            count = int(self.fin.readline())

    def redirect(self):
        pass

    def groupchunks(self, changegroup):
        while True:
            d = changegroup.read(4096)
            if not d:
                break
            yield d

    def sendresponse(self, v):
        self.fout.write("%d\n" % len(v))
        self.fout.write(v)
        self.fout.flush()

    def sendstream(self, source):
        write = self.fout.write
        for chunk in source.gen:
            write(chunk)
        self.fout.flush()

    def sendpushresponse(self, rsp):
        self.sendresponse('')
        self.sendresponse(str(rsp.res))

    def sendpusherror(self, rsp):
        self.sendresponse(rsp.res)

    def sendooberror(self, rsp):
        self.ui.ferr.write('%s\n-\n' % rsp.message)
        self.ui.ferr.flush()
        self.fout.write('\n')
        self.fout.flush()

    def serve_forever(self):
        try:
            while self.serve_one():
                pass
        finally:
            if self.lock is not None:
                self.lock.release()
        sys.exit(0)

    handlers = {
        str: sendresponse,
        wireproto.streamres: sendstream,
        wireproto.pushres: sendpushresponse,
        wireproto.pusherr: sendpusherror,
        wireproto.ooberror: sendooberror,
    }

    def serve_one(self):
        cmd = self.fin.readline()[:-1]
        if cmd and cmd in wireproto.commands:
            rsp = wireproto.dispatch(self.repo, self, cmd)
            self.handlers[rsp.__class__](self, rsp)
        elif cmd:
            impl = getattr(self, 'do_' + cmd, None)
            if impl:
                r = impl()
                if r is not None:
                    self.sendresponse(r)
            else: self.sendresponse("")
        return cmd != ''

    def do_lock(self):
        '''DEPRECATED - allowing remote client to lock repo is not safe'''

        self.lock = self.repo.lock()
        return ""

    def do_unlock(self):
        '''DEPRECATED'''

        if self.lock:
            self.lock.release()
        self.lock = None
        return ""

    def do_addchangegroup(self):
        '''DEPRECATED'''

        if not self.lock:
            self.sendresponse("not locked")
            return

        self.sendresponse("")
        cg = changegroup.unbundle10(self.fin, "UN")
        r = changegroup.addchangegroup(self.repo, cg, 'serve', self._client())
        self.lock.release()
        return str(r)

    def _client(self):
        client = os.environ.get('SSH_CLIENT', '').split(' ', 1)[0]
        return 'remote:ssh:' + client