comparison mercurial/dirstate.py @ 34672:e159f217230e

dirstate: move _read into dirstatemap

As part of separating the dirstate business logic from the storage, let's move
the read code into the new dirstatemap class.

Differential Revision: https://phab.mercurial-scm.org/D977

34671:16d73491416b

        except: # re-raises
            f.discard()
            raise

    def _read(self):
        self._map = dirstatemap(self._ui, self._opener, self._root)

        # ignore HG_PENDING because identity is used only for writing
        self._identity = util.filestat.frompath(
            self._opener.join(self._filename))
        try:
            fp = self._map._opendirstatefile()
            try:
                st = fp.read()
            finally:
                fp.close()
        except IOError as err:
            if err.errno != errno.ENOENT:
                raise
            return
        if not st:
            return

        if util.safehasattr(parsers, 'dict_new_presized'):
            # Make an estimate of the number of files in the dirstate based on
            # its size. From a linear regression on a set of real-world repos,
            # all over 10,000 files, the size of a dirstate entry is 85
            # bytes. The cost of resizing is significantly higher than the cost
            # of filling in a larger presized dict, so subtract 20% from the
            # size.
            #
            # This heuristic is imperfect in many ways, so in a future dirstate
            # format update it makes sense to just record the number of entries
            # on write.
            self._map._map = parsers.dict_new_presized(len(st) / 71)

        # Python's garbage collector triggers a GC each time a certain number
        # of container objects (the number being defined by
        # gc.get_threshold()) are allocated. parse_dirstate creates a tuple
        # for each file in the dirstate. The C version then immediately marks
        # them as not to be tracked by the collector. However, this has no
        # effect on when GCs are triggered, only on what objects the GC looks
        # into. This means that O(number of files) GCs are unavoidable.
        # Depending on when in the process's lifetime the dirstate is parsed,
        # this can get very expensive. As a workaround, disable GC while
        # parsing the dirstate.
        #
        # (we cannot decorate the function directly since it is in a C module)
        parse_dirstate = util.nogc(parsers.parse_dirstate)
        p = parse_dirstate(self._map._map, self._map.copymap, st)
        if not self._map._dirtyparents:
            self._map.setparents(*p)

    def invalidate(self):
        '''Causes the next access to reread the dirstate.

        This is different from localrepo.invalidatedirstate() because it always

        return self._parents

    def setparents(self, p1, p2):
        self._parents = (p1, p2)
        self._dirtyparents = True

34672:e159f217230e

        except: # re-raises
            f.discard()
            raise

    def _read(self):
        # ignore HG_PENDING because identity is used only for writing
        self._identity = util.filestat.frompath(
            self._opener.join(self._filename))
        self._map = dirstatemap(self._ui, self._opener, self._root)
        self._map.read()

    def invalidate(self):
        '''Causes the next access to reread the dirstate.

        This is different from localrepo.invalidatedirstate() because it always

        return self._parents

    def setparents(self, p1, p2):
        self._parents = (p1, p2)
        self._dirtyparents = True

    def read(self):
        try:
            fp = self._opendirstatefile()
            try:
                st = fp.read()
            finally:
                fp.close()
        except IOError as err:
            if err.errno != errno.ENOENT:
                raise
            return
        if not st:
            return

        if util.safehasattr(parsers, 'dict_new_presized'):
            # Make an estimate of the number of files in the dirstate based on
            # its size. From a linear regression on a set of real-world repos,
            # all over 10,000 files, the size of a dirstate entry is 85
            # bytes. The cost of resizing is significantly higher than the cost
            # of filling in a larger presized dict, so subtract 20% from the
            # size.
            #
            # This heuristic is imperfect in many ways, so in a future dirstate
            # format update it makes sense to just record the number of entries
            # on write.
            self._map = parsers.dict_new_presized(len(st) / 71)

        # Python's garbage collector triggers a GC each time a certain number
        # of container objects (the number being defined by
        # gc.get_threshold()) are allocated. parse_dirstate creates a tuple
        # for each file in the dirstate. The C version then immediately marks
        # them as not to be tracked by the collector. However, this has no
        # effect on when GCs are triggered, only on what objects the GC looks
        # into. This means that O(number of files) GCs are unavoidable.
        # Depending on when in the process's lifetime the dirstate is parsed,
        # this can get very expensive. As a workaround, disable GC while
        # parsing the dirstate.
        #
        # (we cannot decorate the function directly since it is in a C module)
        parse_dirstate = util.nogc(parsers.parse_dirstate)
        p = parse_dirstate(self._map, self.copymap, st)
        if not self._dirtyparents:
            self.setparents(*p)