Mercurial > hg
view mercurial/revlogutils/flagutil.py @ 42881:519b45603880
flagprocessors: deprecate _processflags
People should use the specialized version instead now.
Differential Revision: https://phab.mercurial-scm.org/D6806
author | Pierre-Yves David <pierre-yves.david@octobus.net> |
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date | Sat, 07 Sep 2019 10:06:32 -0700 |
parents | 87a934684c3b |
children | 3bed541aa65d |
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# flagutils.py - code to deal with revlog flags and their processors # # Copyright 2016 Remi Chaintron <remi@fb.com> # Copyright 2016-2019 Pierre-Yves David <pierre-yves.david@ens-lyon.org> # # 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 ..i18n import _ from .constants import ( REVIDX_DEFAULT_FLAGS, REVIDX_ELLIPSIS, REVIDX_EXTSTORED, REVIDX_FLAGS_ORDER, REVIDX_ISCENSORED, REVIDX_RAWTEXT_CHANGING_FLAGS, ) from .. import ( error, util ) # blanked usage of all the name to prevent pyflakes constraints # We need these name available in the module for extensions. REVIDX_ISCENSORED REVIDX_ELLIPSIS REVIDX_EXTSTORED REVIDX_DEFAULT_FLAGS REVIDX_FLAGS_ORDER REVIDX_RAWTEXT_CHANGING_FLAGS REVIDX_KNOWN_FLAGS = util.bitsfrom(REVIDX_FLAGS_ORDER) # Store flag processors (cf. 'addflagprocessor()' to register) flagprocessors = { REVIDX_ISCENSORED: None, } def addflagprocessor(flag, processor): """Register a flag processor on a revision data flag. Invariant: - Flags need to be defined in REVIDX_KNOWN_FLAGS and REVIDX_FLAGS_ORDER, and REVIDX_RAWTEXT_CHANGING_FLAGS if they can alter rawtext. - Only one flag processor can be registered on a specific flag. - flagprocessors must be 3-tuples of functions (read, write, raw) with the following signatures: - (read) f(self, rawtext) -> text, bool - (write) f(self, text) -> rawtext, bool - (raw) f(self, rawtext) -> bool "text" is presented to the user. "rawtext" is stored in revlog data, not directly visible to the user. The boolean returned by these transforms is used to determine whether the returned text can be used for hash integrity checking. For example, if "write" returns False, then "text" is used to generate hash. If "write" returns True, that basically means "rawtext" returned by "write" should be used to generate hash. Usually, "write" and "read" return different booleans. And "raw" returns a same boolean as "write". Note: The 'raw' transform is used for changegroup generation and in some debug commands. In this case the transform only indicates whether the contents can be used for hash integrity checks. """ insertflagprocessor(flag, processor, flagprocessors) def insertflagprocessor(flag, processor, flagprocessors): if not flag & REVIDX_KNOWN_FLAGS: msg = _("cannot register processor on unknown flag '%#x'.") % (flag) raise error.ProgrammingError(msg) if flag not in REVIDX_FLAGS_ORDER: msg = _("flag '%#x' undefined in REVIDX_FLAGS_ORDER.") % (flag) raise error.ProgrammingError(msg) if flag in flagprocessors: msg = _("cannot register multiple processors on flag '%#x'.") % (flag) raise error.Abort(msg) flagprocessors[flag] = processor class flagprocessorsmixin(object): """basic mixin to support revlog flag processing Make sure the `_flagprocessors` attribute is set at ``__init__`` time. See the documentation of the ``_processflags`` method for details. """ _flagserrorclass = error.RevlogError def _processflags(self, text, flags, operation, raw=False): """deprecated entry point to access flag processors""" msg = ('_processflag(...) use the specialized variant') util.nouideprecwarn(msg, '5.2', stacklevel=2) if raw: return text, self._processflagsraw(text, flags) elif operation == 'read': return self._processflagsread(text, flags) else: # write operation return self._processflagswrite(text, flags) def _processflagsread(self, text, flags): """Inspect revision data flags and applies read transformations defined by registered flag processors. ``text`` - the revision data to process ``flags`` - the revision flags ``raw`` - an optional argument describing if the raw transform should be applied. This method processes the flags in the order (or reverse order if ``operation`` is 'write') defined by REVIDX_FLAGS_ORDER, applying the flag processors registered for present flags. The order of flags defined in REVIDX_FLAGS_ORDER needs to be stable to allow non-commutativity. Returns a 2-tuple of ``(text, validatehash)`` where ``text`` is the processed text and ``validatehash`` is a bool indicating whether the returned text should be checked for hash integrity. """ return self._processflagsfunc(text, flags, 'read') def _processflagswrite(self, text, flags): """Inspect revision data flags and applies write transformations defined by registered flag processors. ``text`` - the revision data to process ``flags`` - the revision flags This method processes the flags in the order (or reverse order if ``operation`` is 'write') defined by REVIDX_FLAGS_ORDER, applying the flag processors registered for present flags. The order of flags defined in REVIDX_FLAGS_ORDER needs to be stable to allow non-commutativity. Returns a 2-tuple of ``(text, validatehash)`` where ``text`` is the processed text and ``validatehash`` is a bool indicating whether the returned text should be checked for hash integrity. """ return self._processflagsfunc(text, flags, 'write') def _processflagsraw(self, text, flags): """Inspect revision data flags to check is the content hash should be validated. ``text`` - the revision data to process ``flags`` - the revision flags This method processes the flags in the order (or reverse order if ``operation`` is 'write') defined by REVIDX_FLAGS_ORDER, applying the flag processors registered for present flags. The order of flags defined in REVIDX_FLAGS_ORDER needs to be stable to allow non-commutativity. Returns a 2-tuple of ``(text, validatehash)`` where ``text`` is the processed text and ``validatehash`` is a bool indicating whether the returned text should be checked for hash integrity. """ return self._processflagsfunc(text, flags, 'read', raw=True)[1] def _processflagsfunc(self, text, flags, operation, raw=False): # fast path: no flag processors will run if flags == 0: return text, True if not operation in ('read', 'write'): raise error.ProgrammingError(_("invalid '%s' operation") % operation) # Check all flags are known. if flags & ~REVIDX_KNOWN_FLAGS: raise self._flagserrorclass(_("incompatible revision flag '%#x'") % (flags & ~REVIDX_KNOWN_FLAGS)) validatehash = True # Depending on the operation (read or write), the order might be # reversed due to non-commutative transforms. orderedflags = REVIDX_FLAGS_ORDER if operation == 'write': orderedflags = reversed(orderedflags) for flag in orderedflags: # If a flagprocessor has been registered for a known flag, apply the # related operation transform and update result tuple. if flag & flags: vhash = True if flag not in self._flagprocessors: message = _("missing processor for flag '%#x'") % (flag) raise self._flagserrorclass(message) processor = self._flagprocessors[flag] if processor is not None: readtransform, writetransform, rawtransform = processor if raw: vhash = rawtransform(self, text) elif operation == 'read': text, vhash = readtransform(self, text) else: # write operation text, vhash = writetransform(self, text) validatehash = validatehash and vhash return text, validatehash