view mercurial/interfaces/dirstate.py @ 47338:f27f2afb15da

dirstate-tree: Skip readdir() in `hg status -mard`

When running the status algorithm in a mode where we don’t list unknown
or ignored files, all we care about are files that are listed in the dirstate.
We can there for skip making expensive calls to readdir() to list the contents
of filesystem directories, and instead only run stat() to get the filesystem
state of files listed in the dirstate. (This state may be an error for files
that don’t exist anymore on the filesystem.)

On 16 CPU threads, this reduces the time spent in the `status()` function for
`hg status -mard` on an old snapshot of mozilla-central from ~70ms to ~50ms.

Differential Revision: https://phab.mercurial-scm.org/D10752

from __future__ import absolute_import, print_function

import contextlib

from . import util as interfaceutil


class idirstate(interfaceutil.Interface):
    def __init__(
        opener,
        ui,
        root,
        validate,
        sparsematchfn,
        nodeconstants,
        use_dirstate_v2,
    ):
        """Create a new dirstate object.

        opener is an open()-like callable that can be used to open the
        dirstate file; root is the root of the directory tracked by
        the dirstate.
        """

    # TODO: all these private methods and attributes should be made
    # public or removed from the interface.
    _ignore = interfaceutil.Attribute("""Matcher for ignored files.""")

    def _ignorefiles():
        """Return a list of files containing patterns to ignore."""

    def _ignorefileandline(f):
        """Given a file `f`, return the ignore file and line that ignores it."""

    _checklink = interfaceutil.Attribute("""Callable for checking symlinks.""")
    _checkexec = interfaceutil.Attribute("""Callable for checking exec bits.""")

    @contextlib.contextmanager
    def parentchange():
        """Context manager for handling dirstate parents.

        If an exception occurs in the scope of the context manager,
        the incoherent dirstate won't be written when wlock is
        released.
        """

    def pendingparentchange():
        """Returns true if the dirstate is in the middle of a set of changes
        that modify the dirstate parent.
        """

    def hasdir(d):
        pass

    def flagfunc(buildfallback):
        pass

    def getcwd():
        """Return the path from which a canonical path is calculated.

        This path should be used to resolve file patterns or to convert
        canonical paths back to file paths for display. It shouldn't be
        used to get real file paths. Use vfs functions instead.
        """

    def pathto(f, cwd=None):
        pass

    def __getitem__(key):
        """Return the current state of key (a filename) in the dirstate.

        States are:
          n  normal
          m  needs merging
          r  marked for removal
          a  marked for addition
          ?  not tracked
        """

    def __contains__(key):
        """Check if bytestring `key` is known to the dirstate."""

    def __iter__():
        """Iterate the dirstate's contained filenames as bytestrings."""

    def items():
        """Iterate the dirstate's entries as (filename, dirstatetuple).

        As usual, filename is a bytestring.
        """

    iteritems = items

    def parents():
        pass

    def p1():
        pass

    def p2():
        pass

    def branch():
        pass

    def setparents(p1, p2=None):
        """Set dirstate parents to p1 and p2.

        When moving from two parents to one, 'm' merged entries a
        adjusted to normal and previous copy records discarded and
        returned by the call.

        See localrepo.setparents()
        """

    def setbranch(branch):
        pass

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

        This is different from localrepo.invalidatedirstate() because it always
        rereads the dirstate. Use localrepo.invalidatedirstate() if you want to
        check whether the dirstate has changed before rereading it."""

    def copy(source, dest):
        """Mark dest as a copy of source. Unmark dest if source is None."""

    def copied(file):
        pass

    def copies():
        pass

    def normal(f, parentfiledata=None):
        """Mark a file normal and clean.

        parentfiledata: (mode, size, mtime) of the clean file

        parentfiledata should be computed from memory (for mode,
        size), as or close as possible from the point where we
        determined the file was clean, to limit the risk of the
        file having been changed by an external process between the
        moment where the file was determined to be clean and now."""
        pass

    def normallookup(f):
        '''Mark a file normal, but possibly dirty.'''

    def otherparent(f):
        '''Mark as coming from the other parent, always dirty.'''

    def add(f):
        '''Mark a file added.'''

    def remove(f):
        '''Mark a file removed.'''

    def merge(f):
        '''Mark a file merged.'''

    def drop(f):
        '''Drop a file from the dirstate'''

    def normalize(path, isknown=False, ignoremissing=False):
        """
        normalize the case of a pathname when on a casefolding filesystem

        isknown specifies whether the filename came from walking the
        disk, to avoid extra filesystem access.

        If ignoremissing is True, missing path are returned
        unchanged. Otherwise, we try harder to normalize possibly
        existing path components.

        The normalized case is determined based on the following precedence:

        - version of name already stored in the dirstate
        - version of name stored on disk
        - version provided via command arguments
        """

    def clear():
        pass

    def rebuild(parent, allfiles, changedfiles=None):
        pass

    def identity():
        """Return identity of dirstate it to detect changing in storage

        If identity of previous dirstate is equal to this, writing
        changes based on the former dirstate out can keep consistency.
        """

    def write(tr):
        pass

    def addparentchangecallback(category, callback):
        """add a callback to be called when the wd parents are changed

        Callback will be called with the following arguments:
            dirstate, (oldp1, oldp2), (newp1, newp2)

        Category is a unique identifier to allow overwriting an old callback
        with a newer callback.
        """

    def walk(match, subrepos, unknown, ignored, full=True):
        """
        Walk recursively through the directory tree, finding all files
        matched by match.

        If full is False, maybe skip some known-clean files.

        Return a dict mapping filename to stat-like object (either
        mercurial.osutil.stat instance or return value of os.stat()).

        """

    def status(match, subrepos, ignored, clean, unknown):
        """Determine the status of the working copy relative to the
        dirstate and return a pair of (unsure, status), where status is of type
        scmutil.status and:

          unsure:
            files that might have been modified since the dirstate was
            written, but need to be read to be sure (size is the same
            but mtime differs)
          status.modified:
            files that have definitely been modified since the dirstate
            was written (different size or mode)
          status.clean:
            files that have definitely not been modified since the
            dirstate was written
        """

    def matches(match):
        """
        return files in the dirstate (in whatever state) filtered by match
        """

    def savebackup(tr, backupname):
        '''Save current dirstate into backup file'''

    def restorebackup(tr, backupname):
        '''Restore dirstate by backup file'''

    def clearbackup(tr, backupname):
        '''Clear backup file'''