encoding: fix trim() to be O(n) instead of O(n^2)
`encoding.trim()` iterated over the possible lengths smaller than the
input and created a slice for each. It then calculated the column
width of the result, which is of course O(n), so the overall algorithm
was O(n). This patch rewrites it to iterate over the unicode
characters, keeping track of the length so far. Also, the old
algorithm started from the end of the string, which made it much worse
when the input is large and the limit is small (such as the typical 72
we pass to it).
You can time it by running something like this:
```
time python3 -c 'from mercurial.utils import stringutil; print(stringutil.ellipsis(b"0123456789" * 1000, 5))'
```
That drops from 4.05 s to 83 ms with this patch (and most of that is
of course startup time).
Differential Revision: https://phab.mercurial-scm.org/D12089
# Copyright 2016-present Facebook. All Rights Reserved.
#
# protocol: logic for a server providing fastannotate support
#
# 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 contextlib
import os
from mercurial.i18n import _
from mercurial.pycompat import open
from mercurial import (
error,
extensions,
hg,
pycompat,
util,
wireprotov1peer,
wireprotov1server,
)
from mercurial.utils import (
urlutil,
)
from . import context
# common
def _getmaster(ui):
"""get the mainbranch, and enforce it is set"""
master = ui.config(b'fastannotate', b'mainbranch')
if not master:
raise error.Abort(
_(
b'fastannotate.mainbranch is required '
b'for both the client and the server'
)
)
return master
# server-side
def _capabilities(orig, repo, proto):
result = orig(repo, proto)
result.append(b'getannotate')
return result
def _getannotate(repo, proto, path, lastnode):
# output:
# FILE := vfspath + '\0' + str(size) + '\0' + content
# OUTPUT := '' | FILE + OUTPUT
result = b''
buildondemand = repo.ui.configbool(
b'fastannotate', b'serverbuildondemand', True
)
with context.annotatecontext(repo, path) as actx:
if buildondemand:
# update before responding to the client
master = _getmaster(repo.ui)
try:
if not actx.isuptodate(master):
actx.annotate(master, master)
except Exception:
# non-fast-forward move or corrupted. rebuild automically.
actx.rebuild()
try:
actx.annotate(master, master)
except Exception:
actx.rebuild() # delete files
finally:
# although the "with" context will also do a close/flush, we
# need to do it early so we can send the correct respond to
# client.
actx.close()
# send back the full content of revmap and linelog, in the future we
# may want to do some rsync-like fancy updating.
# the lastnode check is not necessary if the client and the server
# agree where the main branch is.
if actx.lastnode != lastnode:
for p in [actx.revmappath, actx.linelogpath]:
if not os.path.exists(p):
continue
with open(p, b'rb') as f:
content = f.read()
vfsbaselen = len(repo.vfs.base + b'/')
relpath = p[vfsbaselen:]
result += b'%s\0%d\0%s' % (relpath, len(content), content)
return result
def _registerwireprotocommand():
if b'getannotate' in wireprotov1server.commands:
return
wireprotov1server.wireprotocommand(b'getannotate', b'path lastnode')(
_getannotate
)
def serveruisetup(ui):
_registerwireprotocommand()
extensions.wrapfunction(wireprotov1server, b'_capabilities', _capabilities)
# client-side
def _parseresponse(payload):
result = {}
i = 0
l = len(payload) - 1
state = 0 # 0: vfspath, 1: size
vfspath = size = b''
while i < l:
ch = payload[i : i + 1]
if ch == b'\0':
if state == 1:
result[vfspath] = payload[i + 1 : i + 1 + int(size)]
i += int(size)
state = 0
vfspath = size = b''
elif state == 0:
state = 1
else:
if state == 1:
size += ch
elif state == 0:
vfspath += ch
i += 1
return result
def peersetup(ui, peer):
class fastannotatepeer(peer.__class__):
@wireprotov1peer.batchable
def getannotate(self, path, lastnode=None):
if not self.capable(b'getannotate'):
ui.warn(_(b'remote peer cannot provide annotate cache\n'))
return None, None
else:
args = {b'path': path, b'lastnode': lastnode or b''}
return args, _parseresponse
peer.__class__ = fastannotatepeer
@contextlib.contextmanager
def annotatepeer(repo):
ui = repo.ui
remotedest = ui.config(b'fastannotate', b'remotepath', b'default')
r = urlutil.get_unique_pull_path(b'fastannotate', repo, ui, remotedest)
remotepath = r[0]
peer = hg.peer(ui, {}, remotepath)
try:
yield peer
finally:
peer.close()
def clientfetch(repo, paths, lastnodemap=None, peer=None):
"""download annotate cache from the server for paths"""
if not paths:
return
if peer is None:
with annotatepeer(repo) as peer:
return clientfetch(repo, paths, lastnodemap, peer)
if lastnodemap is None:
lastnodemap = {}
ui = repo.ui
results = []
with peer.commandexecutor() as batcher:
ui.debug(b'fastannotate: requesting %d files\n' % len(paths))
for p in paths:
results.append(
batcher.callcommand(
b'getannotate',
{b'path': p, b'lastnode': lastnodemap.get(p)},
)
)
for result in results:
r = result.result()
# TODO: pconvert these paths on the server?
r = {util.pconvert(p): v for p, v in pycompat.iteritems(r)}
for path in sorted(r):
# ignore malicious paths
if not path.startswith(b'fastannotate/') or b'/../' in (
path + b'/'
):
ui.debug(
b'fastannotate: ignored malicious path %s\n' % path
)
continue
content = r[path]
if ui.debugflag:
ui.debug(
b'fastannotate: writing %d bytes to %s\n'
% (len(content), path)
)
repo.vfs.makedirs(os.path.dirname(path))
with repo.vfs(path, b'wb') as f:
f.write(content)
def _filterfetchpaths(repo, paths):
"""return a subset of paths whose history is long and need to fetch linelog
from the server. works with remotefilelog and non-remotefilelog repos.
"""
threshold = repo.ui.configint(b'fastannotate', b'clientfetchthreshold', 10)
if threshold <= 0:
return paths
result = []
for path in paths:
try:
if len(repo.file(path)) >= threshold:
result.append(path)
except Exception: # file not found etc.
result.append(path)
return result
def localreposetup(ui, repo):
class fastannotaterepo(repo.__class__):
def prefetchfastannotate(self, paths, peer=None):
master = _getmaster(self.ui)
needupdatepaths = []
lastnodemap = {}
try:
for path in _filterfetchpaths(self, paths):
with context.annotatecontext(self, path) as actx:
if not actx.isuptodate(master, strict=False):
needupdatepaths.append(path)
lastnodemap[path] = actx.lastnode
if needupdatepaths:
clientfetch(self, needupdatepaths, lastnodemap, peer)
except Exception as ex:
# could be directory not writable or so, not fatal
self.ui.debug(b'fastannotate: prefetch failed: %r\n' % ex)
repo.__class__ = fastannotaterepo
def clientreposetup(ui, repo):
_registerwireprotocommand()
if repo.local():
localreposetup(ui, repo)
# TODO: this mutates global state, but only if at least one repo
# has the extension enabled. This is probably bad for hgweb.
if peersetup not in hg.wirepeersetupfuncs:
hg.wirepeersetupfuncs.append(peersetup)