view mercurial/txnutil.py @ 38899:7a154778fb46

changegroup: consolidate tree manifests sending into cg1packer

Previously, we overrode a method to control how manifests were
serialized. This method was redefined on cg3packer to send tree
manifests.

This commit moves the tree manifests sending variation to cg1packer
and teaches the cgpacker constructor to control which version to
use.

After these changes, cg3packer was empty. So it has been removed.

Differential Revision: https://phab.mercurial-scm.org/D4081

# txnutil.py - transaction related utilities
#
#  Copyright FUJIWARA Katsunori <[e-mail]> and others
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

from __future__ import absolute_import

import errno

from . import (
    encoding,
)

def mayhavepending(root):
    '''return whether 'root' may have pending changes, which are
    visible to this process.
    '''
    return root == encoding.environ.get('HG_PENDING')

def trypending(root, vfs, filename, **kwargs):
    '''Open  file to be read according to HG_PENDING environment variable

    This opens '.pending' of specified 'filename' only when HG_PENDING
    is equal to 'root'.

    This returns '(fp, is_pending_opened)' tuple.
    '''
    if mayhavepending(root):
        try:
            return (vfs('%s.pending' % filename, **kwargs), True)
        except IOError as inst:
            if inst.errno != errno.ENOENT:
                raise
    return (vfs(filename, **kwargs), False)