Mercurial > hg-stable
view mercurial/registrar.py @ 39646:9c2c77c73f23
wireprotov2: define and implement "changesetdata" command
This commit introduces the "changesetdata" wire protocol command.
The role of the command is to expose data associated with changelog
revisions, including the raw revision data itself.
This command is the first piece of a new clone/pull strategy that
is built on top of domain-specific commands for data retrieval.
Instead of a monolithic "getbundle" command that transfers all of the
things, we'll be introducing commands for fetching specific pieces
of data.
Since the changeset is the fundamental unit from which we derive
pointers to other data (manifests, file nodes, etc), it makes sense
to start reimplementing pull with this data.
The command accepts as arguments a set of root and head revisions
defining the changesets that should be fetched as well as an explicit
list of nodes. By default, the command returns only the node values:
the client must explicitly request additional fields be added to the
response. Current supported fields are the list of parent nodes and
the revision fulltext.
My plan is to eventually add support for transferring other data
associated with changesets, including phases, bookmarks, obsolescence
markers, etc. Since the response format is CBOR, we'll be able to add
this data into the response object relatively easily (it should be
as simple as adding a key in a map).
The documentation captures a number of TODO items. Some of these may
require BC breaking changes. That's fine: wire protocol v2 is still
highly experimental.
Differential Revision: https://phab.mercurial-scm.org/D4481
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Wed, 12 Sep 2018 10:01:16 -0700 |
parents | 5d3b58472660 |
children | 170926caf44c |
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# 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. There are predefined weights in the 'filesetlang' module. ====== ============================================================= 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 (DEPRECATED) @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, binary=False, symlink=False): 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"). Optional argument 'binary' is a binary files capability of internal merge tool. 'nomerge' merge type implies binary=True. Optional argument 'symlink' is a symlinks capability of inetrnal merge function. 'nomerge' merge type implies symlink=True. '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, binary=False, symlink=False): func.mergetype = mergetype func.onfailure = onfailure func.precheck = precheck binarycap = binary or mergetype == self.nomerge symlinkcap = symlink or mergetype == self.nomerge # actual capabilities, which this internal merge tool has func.capabilities = {"binary": binarycap, "symlink": symlinkcap}