comparison mercurial/tags.py @ 9152:4017291c4c48

tags: support 'instant' tag retrieval (issue548)

- modify _readtagcache() and _writetagcache() to read/write tag->node
  mapping for global tags
- if (and only if) tip unchanged, use that cached mapping to avoid
  reading any revisions of .hgtags
- change so tag names are UTF-8 in memory in tags.py, and converted to
  local encoding as late as possible (in localrepository._findtags())

9151:f528d1a93491

            ui, repo, fctx.data().splitlines(), fctx)
        _updatetags(filetags, "global", alltags, tagtypes)

def findglobaltags2(ui, repo, alltags, tagtypes):
    '''Same as findglobaltags1(), but with caching.'''
    (heads, tagfnode, shouldwrite) = _readtagcache(ui, repo)

    _debug(ui, "reading tags from %d head(s): %s\n"
           % (len(heads), map(short, reversed(heads))))
    seen = set()                    # set of fnode
    fctx = None

            filetags = _readtags(ui, repo, fctx.data().splitlines(), fctx)
            _updatetags(filetags, 'global', alltags, tagtypes)

    # and update the cache (if necessary)
    if shouldwrite:
        _writetagcache(ui, repo, heads, tagfnode)

# Set this to findglobaltags1 to disable tag caching.
findglobaltags = findglobaltags2

def readlocaltags(ui, repo, alltags, tagtypes):
    '''Read local tags in repo.  Update alltags and tagtypes.'''
    try:
        data = encoding.fromlocal(repo.opener("localtags").read())
        # localtags are stored in the local character set
        # while the internal tag table is stored in UTF-8
        filetags = _readtags(
            ui, repo, data.splitlines(), "localtags")
        _updatetags(filetags, "local", alltags, tagtypes)
    except IOError:
        pass

def _readtags(ui, repo, lines, fn):
    '''Read tag definitions from a file (or any source of lines).
    Return a mapping from tag name to (node, hist): node is the node id
    from the last line read for that name, and hist is the list of node
    ids previously associated with it (in file order).  All node ids are
    binary, not hex.'''

        try:
            (nodehex, name) = line.split(" ", 1)
        except ValueError:
            warn(_("cannot parse entry"))
            continue
        name = encoding.tolocal(name.strip()) # stored in UTF-8
        try:
            nodebin = bin(nodehex)
        except TypeError:
            warn(_("node '%s' is not well formed") % nodehex)
            continue

# avoids looking up .hgtags in the manifest for every head, and it
# can avoid calling heads() at all if there have been no changes to
# the repo.

def _readtagcache(ui, repo):
    '''Read the tag cache and return a tuple (heads, fnodes,
    shouldwrite).  heads is the list of all heads currently in the
    repository (ordered from tip to oldest) and fnodes is a mapping from
    head to .hgtags filenode.  Caller is responsible for reading tag
    info from each head.'''

    try:
        cachefile = repo.opener('tags.cache', 'r')
        _debug(ui, 'reading tag cache from %s\n' % cachefile.name)
    except IOError:

    cacherevs = []                      # list of headrev
    cacheheads = []                     # list of headnode
    cachefnode = {}                     # map headnode to filenode
    if cachefile:
        for line in cachefile:
            line = line.rstrip().split()
            cacherevs.append(int(line[0]))
            headnode = bin(line[1])
            cacheheads.append(headnode)
            if len(line) == 3:
                fnode = bin(line[2])
                cachefnode[headnode] = fnode

        cachefile.close()

    tipnode = repo.changelog.tip()
    tiprev = len(repo.changelog) - 1

    # Case 1 (common): tip is the same, so nothing has changed.
    # (Unchanged tip trivially means no changesets have been added.
    # But, thanks to localrepository.destroyed(), it also means none
    # have been destroyed by strip or rollback.)
    if cacheheads and cacheheads[0] == tipnode and cacherevs[0] == tiprev:
        _debug(ui, "tag cache: tip unchanged\n")
        return (cacheheads, cachefnode, False)
        
    repoheads = repo.heads()

    # Case 2 (uncommon): empty repo; get out quickly and don't bother
    # writing an empty cache.
    if repoheads == [nullid]:
        return ([], {}, False)

    # Case 3 (uncommon): cache file missing or empty.
    if not cacheheads:
        _debug(ui, 'tag cache: cache file missing or empty\n')

            # no .hgtags file on this head
            pass

    # Caller has to iterate over all heads, but can use the filenodes in
    # cachefnode to get to each .hgtags revision quickly.
    return (repoheads, cachefnode, True)

def _writetagcache(ui, repo, heads, tagfnode):

    cachefile = repo.opener('tags.cache', 'w', atomictemp=True)
    _debug(ui, 'writing cache file %s\n' % cachefile.name)

    realheads = repo.heads()            # for sanity checks below

        if fnode:
            cachefile.write('%d %s %s\n' % (rev, hex(head), hex(fnode)))
        else:
            cachefile.write('%d %s\n' % (rev, hex(head)))

    cachefile.rename()
    cachefile.close()

9152:4017291c4c48

            ui, repo, fctx.data().splitlines(), fctx)
        _updatetags(filetags, "global", alltags, tagtypes)

def findglobaltags2(ui, repo, alltags, tagtypes):
    '''Same as findglobaltags1(), but with caching.'''
    # This is so we can be lazy and assume alltags contains only global
    # tags when we pass it to _writetagcache().
    assert len(alltags) == len(tagtypes) == 0, \
           "findglobaltags() should be called first"

    (heads, tagfnode, cachetags, shouldwrite) = _readtagcache(ui, repo)
    if cachetags is not None:
        assert not shouldwrite
        # XXX is this really 100% correct?  are there oddball special
        # cases where a global tag should outrank a local tag but won't,
        # because cachetags does not contain rank info?
        _updatetags(cachetags, 'global', alltags, tagtypes)
        return

    _debug(ui, "reading tags from %d head(s): %s\n"
           % (len(heads), map(short, reversed(heads))))
    seen = set()                    # set of fnode
    fctx = None

            filetags = _readtags(ui, repo, fctx.data().splitlines(), fctx)
            _updatetags(filetags, 'global', alltags, tagtypes)

    # and update the cache (if necessary)
    if shouldwrite:
        _writetagcache(ui, repo, heads, tagfnode, alltags)

# Set this to findglobaltags1 to disable tag caching.
findglobaltags = findglobaltags2

def readlocaltags(ui, repo, alltags, tagtypes):
    '''Read local tags in repo.  Update alltags and tagtypes.'''
    try:
        # localtags is in the local encoding; re-encode to UTF-8 on
        # input for consistency with the rest of this module.
        data = repo.opener("localtags").read()
        filetags = _readtags(
            ui, repo, data.splitlines(), "localtags",
            recode=encoding.fromlocal)
        _updatetags(filetags, "local", alltags, tagtypes)
    except IOError:
        pass

def _readtags(ui, repo, lines, fn, recode=None):
    '''Read tag definitions from a file (or any source of lines).
    Return a mapping from tag name to (node, hist): node is the node id
    from the last line read for that name, and hist is the list of node
    ids previously associated with it (in file order).  All node ids are
    binary, not hex.'''

        try:
            (nodehex, name) = line.split(" ", 1)
        except ValueError:
            warn(_("cannot parse entry"))
            continue
        name = name.strip()
        if recode:
            name = recode(name)
        try:
            nodebin = bin(nodehex)
        except TypeError:
            warn(_("node '%s' is not well formed") % nodehex)
            continue

# avoids looking up .hgtags in the manifest for every head, and it
# can avoid calling heads() at all if there have been no changes to
# the repo.

def _readtagcache(ui, repo):
    '''Read the tag cache and return a tuple (heads, fnodes, cachetags,
    shouldwrite).  If the cache is completely up-to-date, cachetags is a
    dict of the form returned by _readtags(); otherwise, it is None and
    heads and fnodes are set.  In that case, heads is the list of all
    heads currently in the repository (ordered from tip to oldest) and
    fnodes is a mapping from head to .hgtags filenode.  If those two are
    set, caller is responsible for reading tag info from each head.'''

    try:
        cachefile = repo.opener('tags.cache', 'r')
        _debug(ui, 'reading tag cache from %s\n' % cachefile.name)
    except IOError:

    cacherevs = []                      # list of headrev
    cacheheads = []                     # list of headnode
    cachefnode = {}                     # map headnode to filenode
    if cachefile:
        for line in cachefile:
            if line == "\n":
                break
            line = line.rstrip().split()
            cacherevs.append(int(line[0]))
            headnode = bin(line[1])
            cacheheads.append(headnode)
            if len(line) == 3:
                fnode = bin(line[2])
                cachefnode[headnode] = fnode

    tipnode = repo.changelog.tip()
    tiprev = len(repo.changelog) - 1

    # Case 1 (common): tip is the same, so nothing has changed.
    # (Unchanged tip trivially means no changesets have been added.
    # But, thanks to localrepository.destroyed(), it also means none
    # have been destroyed by strip or rollback.)
    if cacheheads and cacheheads[0] == tipnode and cacherevs[0] == tiprev:
        _debug(ui, "tag cache: tip unchanged\n")
        tags = _readtags(ui, repo, cachefile, cachefile.name)
        cachefile.close()
        return (None, None, tags, False)
    if cachefile:
        cachefile.close()               # ignore rest of file
        
    repoheads = repo.heads()

    # Case 2 (uncommon): empty repo; get out quickly and don't bother
    # writing an empty cache.
    if repoheads == [nullid]:
        return ([], {}, {}, False)

    # Case 3 (uncommon): cache file missing or empty.
    if not cacheheads:
        _debug(ui, 'tag cache: cache file missing or empty\n')

            # no .hgtags file on this head
            pass

    # Caller has to iterate over all heads, but can use the filenodes in
    # cachefnode to get to each .hgtags revision quickly.
    return (repoheads, cachefnode, None, True)

def _writetagcache(ui, repo, heads, tagfnode, cachetags):

    cachefile = repo.opener('tags.cache', 'w', atomictemp=True)
    _debug(ui, 'writing cache file %s\n' % cachefile.name)

    realheads = repo.heads()            # for sanity checks below

        if fnode:
            cachefile.write('%d %s %s\n' % (rev, hex(head), hex(fnode)))
        else:
            cachefile.write('%d %s\n' % (rev, hex(head)))

    # Tag names in the cache are in UTF-8 -- which is the whole reason
    # we keep them in UTF-8 throughout this module.  If we converted
    # them local encoding on input, we would lose info writing them to
    # the cache.
    cachefile.write('\n')
    for (name, (node, hist)) in cachetags.iteritems():
        cachefile.write("%s %s\n" % (hex(node), name))

    cachefile.rename()
    cachefile.close()