# streamclone.py - streaming clone server support for mercurial

#

# Copyright 2006 Vadim Gelfer <vadim.gelfer@gmail.com>

#

# 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 _

demandload(globals(), "os stat util")

# 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(reverse=True)

    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().'''

    # get consistent snapshot of repo. lock during scan so lock not

    # needed while we stream, and commits can happen.

    lock = repo.lock()

    repo.ui.debug('scanning\n')

    entries = []

    total_bytes = 0

    for name, size in walkrepo(repo.path):

        entries.append((name, size))

        total_bytes += size

    lock.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.opener(name), limit=size):

            fileobj.write(chunk)

    flush = getattr(fileobj, 'flush', None)

    if flush: flush()