mercurial/streamclone.py

Add support for multiple possible bisect results (issue1228, issue1182)

The real reason for both issue is that bisect can not handle cases where there
are multiple possibilities for the result.

Example (from issue1228):
rev 0 -> good
rev 1 -> skipped
rev 2 -> skipped
rev 3 -> skipped
rev 4 -> bad

Note that this patch does not only fix the reported Assertion Error but also
the problem of a non converging bisect:

hg init
for i in `seq 3`; do echo $i > $i; hg add $i; hg ci -m$i; done
hg bisect -b 2
hg bisect -g 0
hg bisect -s

From this state on, you can:
 a) mark as bad forever (non converging!)
 b) mark as good to get an inconsistent state
 c) skip for the Assertion Error

Minor description and code edits by pmezard.

# streamclone.py - streaming clone server support for mercurial
#
# Copyright 2006 Vadim Gelfer <[e-mail]>
#
# This software may be used and distributed according to the terms
# of the GNU General Public License, incorporated herein by reference.

import os, osutil, stat, util, lock

# if server supports streaming clone, it advertises "stream"
# capability with value that is version+flags of repo it is serving.
# client only streams if it can read that repo format.

def walkrepo(root):
    '''iterate over metadata files in repository.
    walk in natural (sorted) order.
    yields 2-tuples: name of .d or .i file, size of file.'''

    strip_count = len(root) + len(os.sep)
    def walk(path, recurse):
        for e, kind, st in osutil.listdir(path, stat=True):
            pe = os.path.join(path, e)
            if kind == stat.S_IFDIR:
                if recurse:
                    for x in walk(pe, True):
                        yield x
            else:
                if kind != stat.S_IFREG or len(e) < 2:
                    continue
                sfx = e[-2:]
                if sfx in ('.d', '.i'):
                    yield pe[strip_count:], st.st_size
    # write file data first
    for x in walk(os.path.join(root, 'data'), True):
        yield x
    # write manifest before changelog
    meta = list(walk(root, False))
    meta.sort()
    meta.reverse()
    for x in meta:
        yield x

# stream file format is simple.
#
# server writes out line that says how many files, how many total
# bytes.  separator is ascii space, byte counts are strings.
#
# then for each file:
#
#   server writes out line that says file name, how many bytes in
#   file.  separator is ascii nul, byte count is string.
#
#   server writes out raw file data.

def stream_out(repo, fileobj, untrusted=False):
    '''stream out all metadata files in repository.
    writes to file-like object, must support write() and optional flush().'''

    if not repo.ui.configbool('server', 'uncompressed', untrusted=untrusted):
        fileobj.write('1\n')
        return

    # get consistent snapshot of repo. lock during scan so lock not
    # needed while we stream, and commits can happen.
    repolock = None
    try:
        try:
            repolock = repo.lock()
        except (lock.LockHeld, lock.LockUnavailable), inst:
            repo.ui.warn('locking the repository failed: %s\n' % (inst,))
            fileobj.write('2\n')
            return

        fileobj.write('0\n')
        repo.ui.debug('scanning\n')
        entries = []
        total_bytes = 0
        for name, size in walkrepo(repo.spath):
            name = repo.decodefn(util.pconvert(name))
            entries.append((name, size))
            total_bytes += size
    finally:
        del repolock

    repo.ui.debug('%d files, %d bytes to transfer\n' %
                  (len(entries), total_bytes))
    fileobj.write('%d %d\n' % (len(entries), total_bytes))
    for name, size in entries:
        repo.ui.debug('sending %s (%d bytes)\n' % (name, size))
        fileobj.write('%s\0%d\n' % (name, size))
        for chunk in util.filechunkiter(repo.sopener(name), limit=size):
            fileobj.write(chunk)
    flush = getattr(fileobj, 'flush', None)
    if flush: flush()