comparison mercurial/repoview.py @ 32478:1cc7c96cad75

hidden: drop the hidden cache logic

The improvement in time complexitty and the speed-up in computation is large
enough that the has little use now. Its update time can even gets in the way. So
we drop it.

This will allow us to unify the static/dynamic blockers logic in the next
changeset.

32477:20c1c2fb8106

# GNU General Public License version 2 or any later version.

from __future__ import absolute_import

import copy
import hashlib
import struct

from .node import nullrev
from . import (
    error,
    obsolete,
    phases,
    tags as tagsmod,
)

            if p != nullrev and p in domain and p not in ancestors:
                ancestors.add(p)
                stack.append(p)
    return ancestors

cacheversion = 1
cachefile = 'cache/hidden'

def cachehash(repo, hideable):
    """return sha1 hash of repository data to identify a valid cache.

    We calculate a sha1 of repo heads and the content of the obsstore and write
    it to the cache. Upon reading we can easily validate by checking the hash
    against the stored one and discard the cache in case the hashes don't match.
    """
    h = hashlib.sha1()
    h.update(''.join(repo.heads()))
    h.update('%d' % hash(frozenset(hideable)))
    return h.digest()

def _writehiddencache(cachefile, cachehash, hidden):
    """write hidden data to a cache file"""
    data = struct.pack('>%ii' % len(hidden), *sorted(hidden))
    cachefile.write(struct.pack(">H", cacheversion))
    cachefile.write(cachehash)
    cachefile.write(data)

def trywritehiddencache(repo, hideable, hidden):
    """write cache of hidden changesets to disk

    Will not write the cache if a wlock cannot be obtained lazily.
    The cache consists of a head of 22byte:
       2 byte    version number of the cache
      20 byte    sha1 to validate the cache
     n*4 byte    hidden revs
    """
    wlock = fh = None
    try:
        wlock = repo.wlock(wait=False)
        # write cache to file
        newhash = cachehash(repo, hideable)
        fh = repo.vfs.open(cachefile, 'w+b', atomictemp=True)
        _writehiddencache(fh, newhash, hidden)
        fh.close()
    except (IOError, OSError):
        repo.ui.debug('error writing hidden changesets cache\n')
    except error.LockHeld:
        repo.ui.debug('cannot obtain lock to write hidden changesets cache\n')
    finally:
        if wlock:
            wlock.release()

def _readhiddencache(repo, cachefilename, newhash):
    hidden = fh = None
    try:
        if repo.vfs.exists(cachefile):
            fh = repo.vfs.open(cachefile, 'rb')
            version, = struct.unpack(">H", fh.read(2))
            oldhash = fh.read(20)
            if (cacheversion, oldhash) == (version, newhash):
                # cache is valid, so we can start reading the hidden revs
                data = fh.read()
                count = len(data) / 4
                hidden = frozenset(struct.unpack('>%ii' % count, data))
        return hidden
    except struct.error:
        repo.ui.debug('corrupted hidden cache\n')
        # No need to fix the content as it will get rewritten
        return None
    except (IOError, OSError):
        repo.ui.debug('cannot read hidden cache\n')
        return None
    finally:
        if fh:
            fh.close()

def tryreadcache(repo, hideable):
    """read a cache if the cache exists and is valid, otherwise returns None."""
    newhash = cachehash(repo, hideable)
    return _readhiddencache(repo, cachefile, newhash)

def computehidden(repo):
    """compute the set of hidden revision to filter

    During most operation hidden should be filtered."""
    assert not repo.changelog.filteredrevs

    hidden = frozenset()
    hideable = hideablerevs(repo)
    if hideable:
        cl = repo.changelog
        hidden = tryreadcache(repo, hideable)
        if hidden is None:
            hidden = frozenset(_getstatichidden(repo))
            trywritehiddencache(repo, hideable, hidden)

        # check if we have wd parents, bookmarks or tags pointing to hidden
        # changesets and remove those.
        dynamic = hidden & revealedrevs(repo)
        if dynamic:

32478:1cc7c96cad75

# GNU General Public License version 2 or any later version.

from __future__ import absolute_import

import copy

from .node import nullrev
from . import (
    obsolete,
    phases,
    tags as tagsmod,
)

            if p != nullrev and p in domain and p not in ancestors:
                ancestors.add(p)
                stack.append(p)
    return ancestors

def computehidden(repo):
    """compute the set of hidden revision to filter

    During most operation hidden should be filtered."""
    assert not repo.changelog.filteredrevs

    hidden = frozenset()
    hideable = hideablerevs(repo)
    if hideable:
        cl = repo.changelog
        hidden = frozenset(_getstatichidden(repo))

        # check if we have wd parents, bookmarks or tags pointing to hidden
        # changesets and remove those.
        dynamic = hidden & revealedrevs(repo)
        if dynamic: