mercurial/streamclone.py

purge: abort with missing files avoiding problems with name-mangling fs

In a name mangling filesystem (e.g. a case insensitive one)
dirstate.walk() can yield filenames different from the ones
stored in the dirstate. This already confuses the status and
add commands, but with purge this may cause data loss.

To prevent this purge refuses to work if there are missing
files and has a 'force' option if the user knows it is safe.

Even with the force option purge checks if any of the missing
files is still available in the working dir: if so there
may be some problem with the underlying filesystem, so it
unconditionally aborts.

# 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.

from i18n import _
import os, 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):
        ents = os.listdir(path)
        ents.sort()
        for e in ents:
            pe = os.path.join(path, e)
            st = os.lstat(pe)
            if stat.S_ISDIR(st.st_mode):
                if recurse:
                    for x in walk(pe, True):
                        yield x
            else:
                if not stat.S_ISREG(st.st_mode) 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):
    '''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'):
        fileobj.write('1\n')
        return

    # get consistent snapshot of repo. lock during scan so lock not
    # needed while we stream, and commits can happen.
    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
    repolock.release()

    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()