diff options
Diffstat (limited to 'websdk/mercurial/tags.py')
| -rw-r--r--[l---------] | websdk/mercurial/tags.py | 293 |
1 files changed, 292 insertions, 1 deletions
diff --git a/websdk/mercurial/tags.py b/websdk/mercurial/tags.py index bda3a6e..0ef4192 120000..100644 --- a/websdk/mercurial/tags.py +++ b/websdk/mercurial/tags.py @@ -1 +1,292 @@ -/usr/share/pyshared/mercurial/tags.py
\ No newline at end of file +# tags.py - read tag info from local repository +# +# Copyright 2009 Matt Mackall <mpm@selenic.com> +# Copyright 2009 Greg Ward <greg@gerg.ca> +# +# This software may be used and distributed according to the terms of the +# GNU General Public License version 2 or any later version. + +# Currently this module only deals with reading and caching tags. +# Eventually, it could take care of updating (adding/removing/moving) +# tags too. + +from node import nullid, bin, hex, short +from i18n import _ +import encoding +import error +import errno + +def findglobaltags(ui, repo, alltags, tagtypes): + '''Find global tags in repo by reading .hgtags from every head that + has a distinct version of it, using a cache to avoid excess work. + Updates the dicts alltags, tagtypes in place: alltags maps tag name + to (node, hist) pair (see _readtags() below), and tagtypes maps tag + name to tag type ("global" in this case).''' + # 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 + + seen = set() # set of fnode + fctx = None + for head in reversed(heads): # oldest to newest + assert head in repo.changelog.nodemap, \ + "tag cache returned bogus head %s" % short(head) + + fnode = tagfnode.get(head) + if fnode and fnode not in seen: + seen.add(fnode) + if not fctx: + fctx = repo.filectx('.hgtags', fileid=fnode) + else: + fctx = fctx.filectx(fnode) + + 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) + +def readlocaltags(ui, repo, alltags, tagtypes): + '''Read local tags in repo. Update alltags and tagtypes.''' + try: + data = repo.opener.read("localtags") + except IOError, inst: + if inst.errno != errno.ENOENT: + raise + return + + # localtags is in the local encoding; re-encode to UTF-8 on + # input for consistency with the rest of this module. + filetags = _readtags( + ui, repo, data.splitlines(), "localtags", + recode=encoding.fromlocal) + _updatetags(filetags, "local", alltags, tagtypes) + +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.''' + + filetags = {} # map tag name to (node, hist) + count = 0 + + def warn(msg): + ui.warn(_("%s, line %s: %s\n") % (fn, count, msg)) + + for line in lines: + count += 1 + if not line: + continue + 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 + + # update filetags + hist = [] + if name in filetags: + n, hist = filetags[name] + hist.append(n) + filetags[name] = (nodebin, hist) + return filetags + +def _updatetags(filetags, tagtype, alltags, tagtypes): + '''Incorporate the tag info read from one file into the two + dictionaries, alltags and tagtypes, that contain all tag + info (global across all heads plus local).''' + + for name, nodehist in filetags.iteritems(): + if name not in alltags: + alltags[name] = nodehist + tagtypes[name] = tagtype + continue + + # we prefer alltags[name] if: + # it supercedes us OR + # mutual supercedes and it has a higher rank + # otherwise we win because we're tip-most + anode, ahist = nodehist + bnode, bhist = alltags[name] + if (bnode != anode and anode in bhist and + (bnode not in ahist or len(bhist) > len(ahist))): + anode = bnode + ahist.extend([n for n in bhist if n not in ahist]) + alltags[name] = anode, ahist + tagtypes[name] = tagtype + + +# The tag cache only stores info about heads, not the tag contents +# from each head. I.e. it doesn't try to squeeze out the maximum +# performance, but is simpler has a better chance of actually +# working correctly. And this gives the biggest performance win: it +# 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('cache/tags', 'r') + # force reading the file for static-http + cachelines = iter(cachefile) + except IOError: + cachefile = None + + # The cache file consists of lines like + # <headrev> <headnode> [<tagnode>] + # where <headrev> and <headnode> redundantly identify a repository + # head from the time the cache was written, and <tagnode> is the + # filenode of .hgtags on that head. Heads with no .hgtags file will + # have no <tagnode>. The cache is ordered from tip to oldest (which + # is part of why <headrev> is there: a quick visual check is all + # that's required to ensure correct order). + # + # This information is enough to let us avoid the most expensive part + # of finding global tags, which is looking up <tagnode> in the + # manifest for each head. + cacherevs = [] # list of headrev + cacheheads = [] # list of headnode + cachefnode = {} # map headnode to filenode + if cachefile: + try: + for line in cachelines: + 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 + except Exception: + # corruption of the tags cache, just recompute it + ui.warn(_('.hg/cache/tags is corrupt, rebuilding it\n')) + cacheheads = [] + cacherevs = [] + cachefnode = {} + + 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: + tags = _readtags(ui, repo, cachelines, 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. + + # Case 4 (uncommon): tip rev decreased. This should only happen + # when we're called from localrepository.destroyed(). Refresh the + # cache so future invocations will not see disappeared heads in the + # cache. + + # Case 5 (common): tip has changed, so we've added/replaced heads. + + # As it happens, the code to handle cases 3, 4, 5 is the same. + + # N.B. in case 4 (nodes destroyed), "new head" really means "newly + # exposed". + newheads = [head + for head in repoheads + if head not in set(cacheheads)] + + # Now we have to lookup the .hgtags filenode for every new head. + # This is the most expensive part of finding tags, so performance + # depends primarily on the size of newheads. Worst case: no cache + # file, so newheads == repoheads. + for head in newheads: + cctx = repo[head] + try: + fnode = cctx.filenode('.hgtags') + cachefnode[head] = fnode + except error.LookupError: + # 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): + + try: + cachefile = repo.opener('cache/tags', 'w', atomictemp=True) + except (OSError, IOError): + return + + realheads = repo.heads() # for sanity checks below + for head in heads: + # temporary sanity checks; these can probably be removed + # once this code has been in crew for a few weeks + assert head in repo.changelog.nodemap, \ + 'trying to write non-existent node %s to tag cache' % short(head) + assert head in realheads, \ + 'trying to write non-head %s to tag cache' % short(head) + assert head != nullid, \ + 'trying to write nullid to tag cache' + + # This can't fail because of the first assert above. When/if we + # remove that assert, we might want to catch LookupError here + # and downgrade it to a warning. + rev = repo.changelog.rev(head) + + fnode = tagfnode.get(head) + 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)) + + try: + cachefile.close() + except (OSError, IOError): + pass |