rust-nodemap: pure Rust example
To run, use `cargo run --release --example nodemap`
This demonstrates that simple scenarios entirely written
in Rust can content themselves with `NodeTree<T>`.
The example mmaps both the nodemap file and the changelog index.
We had of course to include an implementation of `RevlogIndex`
directly, which isn't much at this stage. It felt a bit
prematurate to include it in the lib.
Here are some first performance measurements, obtained with
this example, on a clone of mozilla-central with 440000
changesets:
(create) Nodemap constructed in RAM in 153.638305ms
(query
CAE63161B68962) found in 22.362us: Ok(Some(269489))
(bench) Did 3 queries in 36.418µs (mean 12.139µs)
(bench) Did 50 queries in 184.318µs (mean 3.686µs)
(bench) Did 100000 queries in 31.053461ms (mean 310ns)
To be fair, even between bench runs, results tend to depend whether
the file is still in kernel caches, and it's not so easy to
get back to a real cold start. The worst we've seen was in the
50us ballpark.
In any busy server setting, the pages would always be in RAM.
We hope it's good enough not to be significantly slower on any
concrete Mercurial operation than the C nodetree when fully in RAM,
and of course this implementation has the serious headstart advantage
of persistence.
Differential Revision: https://phab.mercurial-scm.org/D7797
# hook.py - hook support for mercurial
#
# Copyright 2007 Matt Mackall <mpm@selenic.com>
#
# 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 os
import sys
from .i18n import _
from .pycompat import getattr
from . import (
demandimport,
encoding,
error,
extensions,
pycompat,
util,
)
from .utils import (
procutil,
resourceutil,
stringutil,
)
def pythonhook(ui, repo, htype, hname, funcname, args, throw):
'''call python hook. hook is callable object, looked up as
name in python module. if callable returns "true", hook
fails, else passes. if hook raises exception, treated as
hook failure. exception propagates if throw is "true".
reason for "true" meaning "hook failed" is so that
unmodified commands (e.g. mercurial.commands.update) can
be run as hooks without wrappers to convert return values.'''
if callable(funcname):
obj = funcname
funcname = pycompat.sysbytes(obj.__module__ + "." + obj.__name__)
else:
d = funcname.rfind(b'.')
if d == -1:
raise error.HookLoadError(
_(b'%s hook is invalid: "%s" not in a module')
% (hname, funcname)
)
modname = funcname[:d]
oldpaths = sys.path
if resourceutil.mainfrozen():
# binary installs require sys.path manipulation
modpath, modfile = os.path.split(modname)
if modpath and modfile:
sys.path = sys.path[:] + [modpath]
modname = modfile
with demandimport.deactivated():
try:
obj = __import__(pycompat.sysstr(modname))
except (ImportError, SyntaxError):
e1 = sys.exc_info()
try:
# extensions are loaded with hgext_ prefix
obj = __import__("hgext_%s" % pycompat.sysstr(modname))
except (ImportError, SyntaxError):
e2 = sys.exc_info()
if ui.tracebackflag:
ui.warn(
_(
b'exception from first failed import '
b'attempt:\n'
)
)
ui.traceback(e1)
if ui.tracebackflag:
ui.warn(
_(
b'exception from second failed import '
b'attempt:\n'
)
)
ui.traceback(e2)
if not ui.tracebackflag:
tracebackhint = _(
b'run with --traceback for stack trace'
)
else:
tracebackhint = None
raise error.HookLoadError(
_(b'%s hook is invalid: import of "%s" failed')
% (hname, modname),
hint=tracebackhint,
)
sys.path = oldpaths
try:
for p in funcname.split(b'.')[1:]:
obj = getattr(obj, p)
except AttributeError:
raise error.HookLoadError(
_(b'%s hook is invalid: "%s" is not defined')
% (hname, funcname)
)
if not callable(obj):
raise error.HookLoadError(
_(b'%s hook is invalid: "%s" is not callable')
% (hname, funcname)
)
ui.note(_(b"calling hook %s: %s\n") % (hname, funcname))
starttime = util.timer()
try:
r = obj(ui=ui, repo=repo, hooktype=htype, **pycompat.strkwargs(args))
except Exception as exc:
if isinstance(exc, error.Abort):
ui.warn(_(b'error: %s hook failed: %s\n') % (hname, exc.args[0]))
else:
ui.warn(
_(b'error: %s hook raised an exception: %s\n')
% (hname, stringutil.forcebytestr(exc))
)
if throw:
raise
if not ui.tracebackflag:
ui.warn(_(b'(run with --traceback for stack trace)\n'))
ui.traceback()
return True, True
finally:
duration = util.timer() - starttime
ui.log(
b'pythonhook',
b'pythonhook-%s: %s finished in %0.2f seconds\n',
htype,
funcname,
duration,
)
if r:
if throw:
raise error.HookAbort(_(b'%s hook failed') % hname)
ui.warn(_(b'warning: %s hook failed\n') % hname)
return r, False
def _exthook(ui, repo, htype, name, cmd, args, throw):
starttime = util.timer()
env = {}
# make in-memory changes visible to external process
if repo is not None:
tr = repo.currenttransaction()
repo.dirstate.write(tr)
if tr and tr.writepending():
env[b'HG_PENDING'] = repo.root
env[b'HG_HOOKTYPE'] = htype
env[b'HG_HOOKNAME'] = name
for k, v in pycompat.iteritems(args):
if callable(v):
v = v()
if isinstance(v, (dict, list)):
v = stringutil.pprint(v)
env[b'HG_' + k.upper()] = v
if ui.configbool(b'hooks', b'tonative.%s' % name, False):
oldcmd = cmd
cmd = procutil.shelltonative(cmd, env)
if cmd != oldcmd:
ui.note(_(b'converting hook "%s" to native\n') % name)
ui.note(_(b"running hook %s: %s\n") % (name, cmd))
if repo:
cwd = repo.root
else:
cwd = encoding.getcwd()
r = ui.system(cmd, environ=env, cwd=cwd, blockedtag=b'exthook-%s' % (name,))
duration = util.timer() - starttime
ui.log(
b'exthook',
b'exthook-%s: %s finished in %0.2f seconds\n',
name,
cmd,
duration,
)
if r:
desc = procutil.explainexit(r)
if throw:
raise error.HookAbort(_(b'%s hook %s') % (name, desc))
ui.warn(_(b'warning: %s hook %s\n') % (name, desc))
return r
# represent an untrusted hook command
_fromuntrusted = object()
def _allhooks(ui):
"""return a list of (hook-id, cmd) pairs sorted by priority"""
hooks = _hookitems(ui)
# Be careful in this section, propagating the real commands from untrusted
# sources would create a security vulnerability, make sure anything altered
# in that section uses "_fromuntrusted" as its command.
untrustedhooks = _hookitems(ui, _untrusted=True)
for name, value in untrustedhooks.items():
trustedvalue = hooks.get(name, (None, None, name, _fromuntrusted))
if value != trustedvalue:
(lp, lo, lk, lv) = trustedvalue
hooks[name] = (lp, lo, lk, _fromuntrusted)
# (end of the security sensitive section)
return [(k, v) for p, o, k, v in sorted(hooks.values())]
def _hookitems(ui, _untrusted=False):
"""return all hooks items ready to be sorted"""
hooks = {}
for name, cmd in ui.configitems(b'hooks', untrusted=_untrusted):
if name.startswith(b'priority.') or name.startswith(b'tonative.'):
continue
priority = ui.configint(b'hooks', b'priority.%s' % name, 0)
hooks[name] = (-priority, len(hooks), name, cmd)
return hooks
_redirect = False
def redirect(state):
global _redirect
_redirect = state
def hashook(ui, htype):
"""return True if a hook is configured for 'htype'"""
if not ui.callhooks:
return False
for hname, cmd in _allhooks(ui):
if hname.split(b'.')[0] == htype and cmd:
return True
return False
def hook(ui, repo, htype, throw=False, **args):
if not ui.callhooks:
return False
hooks = []
for hname, cmd in _allhooks(ui):
if hname.split(b'.')[0] == htype and cmd:
hooks.append((hname, cmd))
res = runhooks(ui, repo, htype, hooks, throw=throw, **args)
r = False
for hname, cmd in hooks:
r = res[hname][0] or r
return r
def runhooks(ui, repo, htype, hooks, throw=False, **args):
args = pycompat.byteskwargs(args)
res = {}
oldstdout = -1
try:
for hname, cmd in hooks:
if oldstdout == -1 and _redirect:
try:
stdoutno = procutil.stdout.fileno()
stderrno = procutil.stderr.fileno()
# temporarily redirect stdout to stderr, if possible
if stdoutno >= 0 and stderrno >= 0:
procutil.stdout.flush()
oldstdout = os.dup(stdoutno)
os.dup2(stderrno, stdoutno)
except (OSError, AttributeError):
# files seem to be bogus, give up on redirecting (WSGI, etc)
pass
if cmd is _fromuntrusted:
if throw:
raise error.HookAbort(
_(b'untrusted hook %s not executed') % hname,
hint=_(b"see 'hg help config.trusted'"),
)
ui.warn(_(b'warning: untrusted hook %s not executed\n') % hname)
r = 1
raised = False
elif callable(cmd):
r, raised = pythonhook(ui, repo, htype, hname, cmd, args, throw)
elif cmd.startswith(b'python:'):
if cmd.count(b':') >= 2:
path, cmd = cmd[7:].rsplit(b':', 1)
path = util.expandpath(path)
if repo:
path = os.path.join(repo.root, path)
try:
mod = extensions.loadpath(path, b'hghook.%s' % hname)
except Exception:
ui.write(_(b"loading %s hook failed:\n") % hname)
raise
hookfn = getattr(mod, cmd)
else:
hookfn = cmd[7:].strip()
r, raised = pythonhook(
ui, repo, htype, hname, hookfn, args, throw
)
else:
r = _exthook(ui, repo, htype, hname, cmd, args, throw)
raised = False
res[hname] = r, raised
finally:
# The stderr is fully buffered on Windows when connected to a pipe.
# A forcible flush is required to make small stderr data in the
# remote side available to the client immediately.
procutil.stderr.flush()
if _redirect and oldstdout >= 0:
procutil.stdout.flush() # write hook output to stderr fd
os.dup2(oldstdout, stdoutno)
os.close(oldstdout)
return res