branchmap: avoid ancestor computations in absence of non-continous branches
The branchhead computation is one of the more heavy operations for
bigger repositories as it has to scan all changesets and potentially
involves the expensive computation of the ancestor sets. Redo the
computation to handle the common cases directly and use tighter
conditions for when the ancestor scan is necessary. Most importantly,
avoid it completely if the non-continous branches are processed in one
update as seen in the initial computation after a clone.
For the Mercurial repository, it gives a small 2-3% performance boost.
For the NetBSD test repository, it cuts the time in half.
Differential Revision: https://phab.mercurial-scm.org/D9631
# Copyright 2020 Joerg Sonnenberger <joerg@bec.de>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
"""export repositories as git fast-import stream"""
# The format specification for fast-import streams can be found at
# https://git-scm.com/docs/git-fast-import#_input_format
from __future__ import absolute_import
import re
from mercurial.i18n import _
from mercurial.node import hex, nullrev
from mercurial.utils import stringutil
from mercurial import (
error,
pycompat,
registrar,
scmutil,
)
from .convert import convcmd
# Note for extension authors: ONLY specify testedwith = 'ships-with-hg-core' for
# extensions which SHIP WITH MERCURIAL. Non-mainline extensions should
# be specifying the version(s) of Mercurial they are tested with, or
# leave the attribute unspecified.
testedwith = b"ships-with-hg-core"
cmdtable = {}
command = registrar.command(cmdtable)
GIT_PERSON_PROHIBITED = re.compile(b'[<>\n"]')
GIT_EMAIL_PROHIBITED = re.compile(b"[<> \n]")
def convert_to_git_user(authormap, user, rev):
mapped_user = authormap.get(user, user)
user_person = stringutil.person(mapped_user)
user_email = stringutil.email(mapped_user)
if GIT_EMAIL_PROHIBITED.match(user_email) or GIT_PERSON_PROHIBITED.match(
user_person
):
raise error.Abort(
_(b"Unable to parse user into person and email for revision %s")
% rev
)
if user_person:
return b'"' + user_person + b'" <' + user_email + b'>'
else:
return b"<" + user_email + b">"
def convert_to_git_date(date):
timestamp, utcoff = date
tzsign = b"+" if utcoff <= 0 else b"-"
if utcoff % 60 != 0:
raise error.Abort(
_(b"UTC offset in %b is not an integer number of seconds") % (date,)
)
utcoff = abs(utcoff) // 60
tzh = utcoff // 60
tzmin = utcoff % 60
return b"%d " % int(timestamp) + tzsign + b"%02d%02d" % (tzh, tzmin)
def convert_to_git_ref(branch):
# XXX filter/map depending on git restrictions
return b"refs/heads/" + branch
def write_data(buf, data, skip_newline):
buf.append(b"data %d\n" % len(data))
buf.append(data)
if not skip_newline or data[-1:] != b"\n":
buf.append(b"\n")
def export_commit(ui, repo, rev, marks, authormap):
ctx = repo[rev]
revid = ctx.hex()
if revid in marks:
ui.debug(b"warning: revision %s already exported, skipped\n" % revid)
return
parents = [p for p in ctx.parents() if p.rev() != nullrev]
for p in parents:
if p.hex() not in marks:
ui.warn(
_(b"warning: parent %s of %s has not been exported, skipped\n")
% (p, revid)
)
return
# For all files modified by the commit, check if they have already
# been exported and otherwise dump the blob with the new mark.
for fname in ctx.files():
if fname not in ctx:
continue
filectx = ctx.filectx(fname)
filerev = hex(filectx.filenode())
if filerev not in marks:
mark = len(marks) + 1
marks[filerev] = mark
data = filectx.data()
buf = [b"blob\n", b"mark :%d\n" % mark]
write_data(buf, data, False)
ui.write(*buf, keepprogressbar=True)
del buf
# Assign a mark for the current revision for references by
# latter merge commits.
mark = len(marks) + 1
marks[revid] = mark
ref = convert_to_git_ref(ctx.branch())
buf = [
b"commit %s\n" % ref,
b"mark :%d\n" % mark,
b"committer %s %s\n"
% (
convert_to_git_user(authormap, ctx.user(), revid),
convert_to_git_date(ctx.date()),
),
]
write_data(buf, ctx.description(), True)
if parents:
buf.append(b"from :%d\n" % marks[parents[0].hex()])
if len(parents) == 2:
buf.append(b"merge :%d\n" % marks[parents[1].hex()])
p0ctx = repo[parents[0]]
files = ctx.manifest().diff(p0ctx.manifest())
else:
files = ctx.files()
filebuf = []
for fname in files:
if fname not in ctx:
filebuf.append((fname, b"D %s\n" % fname))
else:
filectx = ctx.filectx(fname)
filerev = filectx.filenode()
fileperm = b"755" if filectx.isexec() else b"644"
changed = b"M %s :%d %s\n" % (fileperm, marks[hex(filerev)], fname)
filebuf.append((fname, changed))
filebuf.sort()
buf.extend(changed for (fname, changed) in filebuf)
del filebuf
buf.append(b"\n")
ui.write(*buf, keepprogressbar=True)
del buf
isrev = re.compile(b"^[0-9a-f]{40}$")
@command(
b"fastexport",
[
(b"r", b"rev", [], _(b"revisions to export"), _(b"REV")),
(b"i", b"import-marks", b"", _(b"old marks file to read"), _(b"FILE")),
(b"e", b"export-marks", b"", _(b"new marks file to write"), _(b"FILE")),
(
b"A",
b"authormap",
b"",
_(b"remap usernames using this file"),
_(b"FILE"),
),
],
_(b"[OPTION]... [REV]..."),
helpcategory=command.CATEGORY_IMPORT_EXPORT,
)
def fastexport(ui, repo, *revs, **opts):
"""export repository as git fast-import stream
This command lets you dump a repository as a human-readable text stream.
It can be piped into corresponding import routines like "git fast-import".
Incremental dumps can be created by using marks files.
"""
opts = pycompat.byteskwargs(opts)
revs += tuple(opts.get(b"rev", []))
if not revs:
revs = scmutil.revrange(repo, [b":"])
else:
revs = scmutil.revrange(repo, revs)
if not revs:
raise error.Abort(_(b"no revisions matched"))
authorfile = opts.get(b"authormap")
if authorfile:
authormap = convcmd.readauthormap(ui, authorfile)
else:
authormap = {}
import_marks = opts.get(b"import_marks")
marks = {}
if import_marks:
with open(import_marks, "rb") as import_marks_file:
for line in import_marks_file:
line = line.strip()
if not isrev.match(line) or line in marks:
raise error.Abort(_(b"Corrupted marks file"))
marks[line] = len(marks) + 1
revs.sort()
with ui.makeprogress(
_(b"exporting"), unit=_(b"revisions"), total=len(revs)
) as progress:
for rev in revs:
export_commit(ui, repo, rev, marks, authormap)
progress.increment()
export_marks = opts.get(b"export_marks")
if export_marks:
with open(export_marks, "wb") as export_marks_file:
output_marks = [None] * len(marks)
for k, v in marks.items():
output_marks[v - 1] = k
for k in output_marks:
export_marks_file.write(k + b"\n")