mercurial/sshserver.py

add support for streaming clone.

existing clone code uses pull to get changes from remote repo.  is very
slow, uses lots of memory and cpu.

new clone code has server write file data straight to client, client
writes file data straight to disk.  memory and cpu used are very low,
clone is much faster over lan.

new client can still clone with pull, can still clone from older servers.
new server can still serve older clients.

# sshserver.py - ssh protocol server support for mercurial
#
# Copyright 2005 Matt Mackall <[e-mail]>
#
# This software may be used and distributed according to the terms
# of the GNU General Public License, incorporated herein by reference.

from demandload import demandload
from i18n import gettext as _
from node import *
demandload(globals(), "os streamclone sys tempfile util")

class sshserver(object):
    def __init__(self, ui, repo):
        self.ui = ui
        self.repo = repo
        self.lock = None
        self.fin = sys.stdin
        self.fout = sys.stdout

        sys.stdout = sys.stderr

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

    def getarg(self):
        argline = self.fin.readline()[:-1]
        arg, l = argline.split()
        val = self.fin.read(int(l))
        return arg, val

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

    def serve_forever(self):
        while self.serve_one(): pass
        sys.exit(0)

    def serve_one(self):
        cmd = self.fin.readline()[:-1]
        if cmd:
            impl = getattr(self, 'do_' + cmd, None)
            if impl: impl()
            else: self.respond("")
        return cmd != ''

    def do_heads(self):
        h = self.repo.heads()
        self.respond(" ".join(map(hex, h)) + "\n")

    def do_hello(self):
        '''the hello command returns a set of lines describing various
        interesting things about the server, in an RFC822-like format.
        Currently the only one defined is "capabilities", which
        consists of a line in the form:

        capabilities: space separated list of tokens
        '''

        r = "capabilities: unbundle stream=%d\n" % (self.repo.revlogversion,)
        self.respond(r)

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

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

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

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

    def do_branches(self):
        arg, nodes = self.getarg()
        nodes = map(bin, nodes.split(" "))
        r = []
        for b in self.repo.branches(nodes):
            r.append(" ".join(map(hex, b)) + "\n")
        self.respond("".join(r))

    def do_between(self):
        arg, pairs = self.getarg()
        pairs = [map(bin, p.split("-")) for p in pairs.split(" ")]
        r = []
        for b in self.repo.between(pairs):
            r.append(" ".join(map(hex, b)) + "\n")
        self.respond("".join(r))

    def do_changegroup(self):
        nodes = []
        arg, roots = self.getarg()
        nodes = map(bin, roots.split(" "))

        cg = self.repo.changegroup(nodes, 'serve')
        while True:
            d = cg.read(4096)
            if not d:
                break
            self.fout.write(d)

        self.fout.flush()

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

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

        self.respond("")
        r = self.repo.addchangegroup(self.fin, 'serve')
        self.respond(str(r))

    def do_unbundle(self):
        their_heads = self.getarg()[1].split()

        def check_heads():
            heads = map(hex, self.repo.heads())
            return their_heads == [hex('force')] or their_heads == heads

        # fail early if possible
        if not check_heads():
            self.respond(_('unsynced changes'))
            return

        self.respond('')

        # write bundle data to temporary file because it can be big

        try:
            fd, tempname = tempfile.mkstemp(prefix='hg-unbundle-')
            fp = os.fdopen(fd, 'wb+')

            count = int(self.fin.readline())
            while count:
                fp.write(self.fin.read(count))
                count = int(self.fin.readline())

            was_locked = self.lock is not None
            if not was_locked:
                self.lock = self.repo.lock()
            try:
                if not check_heads():
                    # someone else committed/pushed/unbundled while we
                    # were transferring data
                    self.respond(_('unsynced changes'))
                    return
                self.respond('')

                # push can proceed

                fp.seek(0)
                r = self.repo.addchangegroup(fp, 'serve')
                self.respond(str(r))
            finally:
                if not was_locked:
                    self.lock.release()
                    self.lock = None
        finally:
            fp.close()
            os.unlink(tempname)

    def do_stream_out(self):
        streamclone.stream_out(self.repo, self.fout)