revlog: remove some knowledge of sentinel nullid in index
I think the "-2" to mean "last position in index, not counting the
null revision at the end" is an implementation detail of the index
that we should avoid spreading knowledge of. I hope we can even remove
support for index[-2].
Differential Revision: https://phab.mercurial-scm.org/D4016
# registrar.py - utilities to register function for specific purpose
#
# Copyright FUJIWARA Katsunori <foozy@lares.dti.ne.jp> 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
from . import (
configitems,
error,
pycompat,
util,
)
# unlike the other registered items, config options are neither functions or
# classes. Registering the option is just small function call.
#
# We still add the official API to the registrar module for consistency with
# the other items extensions want might to register.
configitem = configitems.getitemregister
class _funcregistrarbase(object):
"""Base of decorator to register a function for specific purpose
This decorator stores decorated functions into own dict 'table'.
The least derived class can be defined by overriding 'formatdoc',
for example::
class keyword(_funcregistrarbase):
_docformat = ":%s: %s"
This should be used as below:
keyword = registrar.keyword()
@keyword('bar')
def barfunc(*args, **kwargs):
'''Explanation of bar keyword ....
'''
pass
In this case:
- 'barfunc' is stored as 'bar' in '_table' of an instance 'keyword' above
- 'barfunc.__doc__' becomes ":bar: Explanation of bar keyword"
"""
def __init__(self, table=None):
if table is None:
self._table = {}
else:
self._table = table
def __call__(self, decl, *args, **kwargs):
return lambda func: self._doregister(func, decl, *args, **kwargs)
def _doregister(self, func, decl, *args, **kwargs):
name = self._getname(decl)
if name in self._table:
msg = 'duplicate registration for name: "%s"' % name
raise error.ProgrammingError(msg)
if func.__doc__ and not util.safehasattr(func, '_origdoc'):
doc = pycompat.sysbytes(func.__doc__).strip()
func._origdoc = doc
func.__doc__ = pycompat.sysstr(self._formatdoc(decl, doc))
self._table[name] = func
self._extrasetup(name, func, *args, **kwargs)
return func
def _parsefuncdecl(self, decl):
"""Parse function declaration and return the name of function in it
"""
i = decl.find('(')
if i >= 0:
return decl[:i]
else:
return decl
def _getname(self, decl):
"""Return the name of the registered function from decl
Derived class should override this, if it allows more
descriptive 'decl' string than just a name.
"""
return decl
_docformat = None
def _formatdoc(self, decl, doc):
"""Return formatted document of the registered function for help
'doc' is '__doc__.strip()' of the registered function.
"""
return self._docformat % (decl, doc)
def _extrasetup(self, name, func):
"""Execute exra setup for registered function, if needed
"""
class command(_funcregistrarbase):
"""Decorator to register a command function to table
This class receives a command table as its argument. The table should
be a dict.
The created object can be used as a decorator for adding commands to
that command table. This accepts multiple arguments to define a command.
The first argument is the command name (as bytes).
The `options` keyword argument is an iterable of tuples defining command
arguments. See ``mercurial.fancyopts.fancyopts()`` for the format of each
tuple.
The `synopsis` argument defines a short, one line summary of how to use the
command. This shows up in the help output.
There are three arguments that control what repository (if any) is found
and passed to the decorated function: `norepo`, `optionalrepo`, and
`inferrepo`.
The `norepo` argument defines whether the command does not require a
local repository. Most commands operate against a repository, thus the
default is False. When True, no repository will be passed.
The `optionalrepo` argument defines whether the command optionally requires
a local repository. If no repository can be found, None will be passed
to the decorated function.
The `inferrepo` argument defines whether to try to find a repository from
the command line arguments. If True, arguments will be examined for
potential repository locations. See ``findrepo()``. If a repository is
found, it will be used and passed to the decorated function.
The `intents` argument defines a set of intended actions or capabilities
the command is taking. These intents can be used to affect the construction
of the repository object passed to the command. For example, commands
declaring that they are read-only could receive a repository that doesn't
have any methods allowing repository mutation. Other intents could be used
to prevent the command from running if the requested intent could not be
fulfilled.
The following intents are defined:
readonly
The command is read-only
The signature of the decorated function looks like this:
def cmd(ui[, repo] [, <args>] [, <options>])
`repo` is required if `norepo` is False.
`<args>` are positional args (or `*args`) arguments, of non-option
arguments from the command line.
`<options>` are keyword arguments (or `**options`) of option arguments
from the command line.
See the WritingExtensions and MercurialApi documentation for more exhaustive
descriptions and examples.
"""
def _doregister(self, func, name, options=(), synopsis=None,
norepo=False, optionalrepo=False, inferrepo=False,
intents=None):
func.norepo = norepo
func.optionalrepo = optionalrepo
func.inferrepo = inferrepo
func.intents = intents or set()
if synopsis:
self._table[name] = func, list(options), synopsis
else:
self._table[name] = func, list(options)
return func
INTENT_READONLY = b'readonly'
class revsetpredicate(_funcregistrarbase):
"""Decorator to register revset predicate
Usage::
revsetpredicate = registrar.revsetpredicate()
@revsetpredicate('mypredicate(arg1, arg2[, arg3])')
def mypredicatefunc(repo, subset, x):
'''Explanation of this revset predicate ....
'''
pass
The first string argument is used also in online help.
Optional argument 'safe' indicates whether a predicate is safe for
DoS attack (False by default).
Optional argument 'takeorder' indicates whether a predicate function
takes ordering policy as the last argument.
Optional argument 'weight' indicates the estimated run-time cost, useful
for static optimization, default is 1. Higher weight means more expensive.
Usually, revsets that are fast and return only one revision has a weight of
0.5 (ex. a symbol); revsets with O(changelog) complexity and read only the
changelog have weight 10 (ex. author); revsets reading manifest deltas have
weight 30 (ex. adds); revset reading manifest contents have weight 100
(ex. contains). Note: those values are flexible. If the revset has a
same big-O time complexity as 'contains', but with a smaller constant, it
might have a weight of 90.
'revsetpredicate' instance in example above can be used to
decorate multiple functions.
Decorated functions are registered automatically at loading
extension, if an instance named as 'revsetpredicate' is used for
decorating in extension.
Otherwise, explicit 'revset.loadpredicate()' is needed.
"""
_getname = _funcregistrarbase._parsefuncdecl
_docformat = "``%s``\n %s"
def _extrasetup(self, name, func, safe=False, takeorder=False, weight=1):
func._safe = safe
func._takeorder = takeorder
func._weight = weight
class filesetpredicate(_funcregistrarbase):
"""Decorator to register fileset predicate
Usage::
filesetpredicate = registrar.filesetpredicate()
@filesetpredicate('mypredicate()')
def mypredicatefunc(mctx, x):
'''Explanation of this fileset predicate ....
'''
pass
The first string argument is used also in online help.
Optional argument 'callstatus' indicates whether a predicate
implies 'matchctx.status()' at runtime or not (False, by
default).
Optional argument 'weight' indicates the estimated run-time cost, useful
for static optimization, default is 1. Higher weight means more expensive.
====== =============================================================
Weight Description and examples
====== =============================================================
0.5 basic match patterns (e.g. a symbol)
10 computing status (e.g. added()) or accessing a few files
30 reading file content for each (e.g. grep())
50 scanning working directory (ignored())
====== =============================================================
'filesetpredicate' instance in example above can be used to
decorate multiple functions.
Decorated functions are registered automatically at loading
extension, if an instance named as 'filesetpredicate' is used for
decorating in extension.
Otherwise, explicit 'fileset.loadpredicate()' is needed.
"""
_getname = _funcregistrarbase._parsefuncdecl
_docformat = "``%s``\n %s"
def _extrasetup(self, name, func, callstatus=False, weight=1):
func._callstatus = callstatus
func._weight = weight
class _templateregistrarbase(_funcregistrarbase):
"""Base of decorator to register functions as template specific one
"""
_docformat = ":%s: %s"
class templatekeyword(_templateregistrarbase):
"""Decorator to register template keyword
Usage::
templatekeyword = registrar.templatekeyword()
# new API (since Mercurial 4.6)
@templatekeyword('mykeyword', requires={'repo', 'ctx'})
def mykeywordfunc(context, mapping):
'''Explanation of this template keyword ....
'''
pass
# old API
@templatekeyword('mykeyword')
def mykeywordfunc(repo, ctx, templ, cache, revcache, **args):
'''Explanation of this template keyword ....
'''
pass
The first string argument is used also in online help.
Optional argument 'requires' should be a collection of resource names
which the template keyword depends on. This also serves as a flag to
switch to the new API. If 'requires' is unspecified, all template
keywords and resources are expanded to the function arguments.
'templatekeyword' instance in example above can be used to
decorate multiple functions.
Decorated functions are registered automatically at loading
extension, if an instance named as 'templatekeyword' is used for
decorating in extension.
Otherwise, explicit 'templatekw.loadkeyword()' is needed.
"""
def _extrasetup(self, name, func, requires=None):
func._requires = requires
class templatefilter(_templateregistrarbase):
"""Decorator to register template filer
Usage::
templatefilter = registrar.templatefilter()
@templatefilter('myfilter', intype=bytes)
def myfilterfunc(text):
'''Explanation of this template filter ....
'''
pass
The first string argument is used also in online help.
Optional argument 'intype' defines the type of the input argument,
which should be (bytes, int, templateutil.date, or None for any.)
'templatefilter' instance in example above can be used to
decorate multiple functions.
Decorated functions are registered automatically at loading
extension, if an instance named as 'templatefilter' is used for
decorating in extension.
Otherwise, explicit 'templatefilters.loadkeyword()' is needed.
"""
def _extrasetup(self, name, func, intype=None):
func._intype = intype
class templatefunc(_templateregistrarbase):
"""Decorator to register template function
Usage::
templatefunc = registrar.templatefunc()
@templatefunc('myfunc(arg1, arg2[, arg3])', argspec='arg1 arg2 arg3',
requires={'ctx'})
def myfuncfunc(context, mapping, args):
'''Explanation of this template function ....
'''
pass
The first string argument is used also in online help.
If optional 'argspec' is defined, the function will receive 'args' as
a dict of named arguments. Otherwise 'args' is a list of positional
arguments.
Optional argument 'requires' should be a collection of resource names
which the template function depends on.
'templatefunc' instance in example above can be used to
decorate multiple functions.
Decorated functions are registered automatically at loading
extension, if an instance named as 'templatefunc' is used for
decorating in extension.
Otherwise, explicit 'templatefuncs.loadfunction()' is needed.
"""
_getname = _funcregistrarbase._parsefuncdecl
def _extrasetup(self, name, func, argspec=None, requires=()):
func._argspec = argspec
func._requires = requires
class internalmerge(_funcregistrarbase):
"""Decorator to register in-process merge tool
Usage::
internalmerge = registrar.internalmerge()
@internalmerge('mymerge', internalmerge.mergeonly,
onfailure=None, precheck=None):
def mymergefunc(repo, mynode, orig, fcd, fco, fca,
toolconf, files, labels=None):
'''Explanation of this internal merge tool ....
'''
return 1, False # means "conflicted", "no deletion needed"
The first string argument is used to compose actual merge tool name,
":name" and "internal:name" (the latter is historical one).
The second argument is one of merge types below:
========== ======== ======== =========
merge type precheck premerge fullmerge
========== ======== ======== =========
nomerge x x x
mergeonly o x o
fullmerge o o o
========== ======== ======== =========
Optional argument 'onfailure' is the format of warning message
to be used at failure of merging (target filename is specified
at formatting). Or, None or so, if warning message should be
suppressed.
Optional argument 'precheck' is the function to be used
before actual invocation of internal merge tool itself.
It takes as same arguments as internal merge tool does, other than
'files' and 'labels'. If it returns false value, merging is aborted
immediately (and file is marked as "unresolved").
'internalmerge' instance in example above can be used to
decorate multiple functions.
Decorated functions are registered automatically at loading
extension, if an instance named as 'internalmerge' is used for
decorating in extension.
Otherwise, explicit 'filemerge.loadinternalmerge()' is needed.
"""
_docformat = "``:%s``\n %s"
# merge type definitions:
nomerge = None
mergeonly = 'mergeonly' # just the full merge, no premerge
fullmerge = 'fullmerge' # both premerge and merge
def _extrasetup(self, name, func, mergetype,
onfailure=None, precheck=None):
func.mergetype = mergetype
func.onfailure = onfailure
func.precheck = precheck