unionrevlog: extract 'baserevision' and 'baserevdiff' methods

This makes possible to use unionrevlog class with subclasses of revlog that
override revlog's 'revision' and 'revdiff' methods. In particular this change
is necessary to implement manifest compression, as it allows extension to
replace manifest class and override 'revision' amd 'revdiff' methods there.

mercurial/unionrepo.py

@@ -1,208 +1,239 b''
 # unionrepo.py - repository class for viewing union of repository changesets
 #
 # Derived from bundlerepo.py
 # Copyright 2006, 2007 Benoit Boissinot <[e-mail]>
 # Copyright 2013 Unity Technologies, Mads Kiilerich <[e-mail]>
 #
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2 or any later version.
 
 """Repository class for "in-memory pull" of one local repository to another,
 allowing operations like diff and log with revsets.
 """
 
 from node import nullid
 from i18n import _
 import os
 import util, mdiff, cmdutil, scmutil
 import localrepo, changelog, manifest, filelog, revlog
 
 class unionrevlog(revlog.revlog):
     def __init__(self, opener, indexfile, revlog2, linkmapper):
         # How it works:
         # To retrieve a revision, we just need to know the node id so we can
         # look it up in revlog2.
         #
         # To differentiate a rev in the second revlog from a rev in the revlog,
         # we check revision against repotiprev.
         opener = scmutil.readonlyvfs(opener)
         revlog.revlog.__init__(self, opener, indexfile)
         self.revlog2 = revlog2
 
         n = len(self)
         self.repotiprev = n - 1
         self.bundlerevs = set() # used by 'bundle()' revset expression
         for rev2 in self.revlog2:
             rev = self.revlog2.index[rev2]
             # rev numbers - in revlog2, very different from self.rev
             _start, _csize, _rsize, _base, linkrev, p1rev, p2rev, node = rev
 
             if linkmapper is None: # link is to same revlog
                 assert linkrev == rev2 # we never link back
                 link = n
             else: # rev must be mapped from repo2 cl to unified cl by linkmapper
                 link = linkmapper(linkrev)
 
             if node in self.nodemap:
                 # this happens for the common revlog revisions
                 self.bundlerevs.add(self.nodemap[node])
                 continue
 
             p1node = self.revlog2.node(p1rev)
             p2node = self.revlog2.node(p2rev)
 
             e = (None, None, None, None,
                  link, self.rev(p1node), self.rev(p2node), node)
             self.index.insert(-1, e)
             self.nodemap[node] = n
             self.bundlerevs.add(n)
             n += 1
 
     def _chunk(self, rev):
         if rev <= self.repotiprev:
             return revlog.revlog._chunk(self, rev)
         return self.revlog2._chunk(self.node(rev))
 
     def revdiff(self, rev1, rev2):
         """return or calculate a delta between two revisions"""
         if rev1 > self.repotiprev and rev2 > self.repotiprev:
             return self.revlog2.revdiff(
                 self.revlog2.rev(self.node(rev1)),
                 self.revlog2.rev(self.node(rev2)))
         elif rev1 <= self.repotiprev and rev2 <= self.repotiprev:
-            return revlog.revlog.revdiff(self, rev1, rev2)
+            return self.baserevdiff(rev1, rev2)
 
         return mdiff.textdiff(self.revision(self.node(rev1)),
                               self.revision(self.node(rev2)))
 
     def revision(self, nodeorrev):
         """return an uncompressed revision of a given node or revision
         number.
         """
         if isinstance(nodeorrev, int):
             rev = nodeorrev
             node = self.node(rev)
         else:
             node = nodeorrev
             rev = self.rev(node)
 
         if node == nullid:
             return ""
 
         if rev > self.repotiprev:
             text = self.revlog2.revision(node)
             self._cache = (node, rev, text)
         else:
-            text = revlog.revlog.revision(self, rev)
+            text = self.baserevision(rev)
             # already cached
         return text
 
+    def baserevision(self, nodeorrev):
+        # Revlog subclasses may override 'revision' method to modify format of
+        # content retrieved from revlog. To use unionrevlog with such class one
+        # needs to override 'baserevision' and make more specific call here.
+        return revlog.revlog.revision(self, nodeorrev)
+
+    def baserevdiff(self, rev1, rev2):
+        # Exists for the same purpose as baserevision.
+        return revlog.revlog.revdiff(self, rev1, rev2)
+
     def addrevision(self, text, transaction, link, p1=None, p2=None, d=None):
         raise NotImplementedError
     def addgroup(self, revs, linkmapper, transaction):
         raise NotImplementedError
     def strip(self, rev, minlink):
         raise NotImplementedError
     def checksize(self):
         raise NotImplementedError
 
 class unionchangelog(unionrevlog, changelog.changelog):
     def __init__(self, opener, opener2):
         changelog.changelog.__init__(self, opener)
         linkmapper = None
         changelog2 = changelog.changelog(opener2)
         unionrevlog.__init__(self, opener, self.indexfile, changelog2,
                              linkmapper)
 
+    def baserevision(self, nodeorrev):
+        # Although changelog doesn't override 'revision' method, some extensions
+        # may replace this class with another that does. Same story with
+        # manifest and filelog classes.
+        return changelog.changelog.revision(self, nodeorrev)
+
+    def baserevdiff(self, rev1, rev2):
+        return changelog.changelog.revdiff(self, rev1, rev2)
+
 class unionmanifest(unionrevlog, manifest.manifest):
     def __init__(self, opener, opener2, linkmapper):
         manifest.manifest.__init__(self, opener)
         manifest2 = manifest.manifest(opener2)
         unionrevlog.__init__(self, opener, self.indexfile, manifest2,
                              linkmapper)
 
+    def baserevision(self, nodeorrev):
+        return manifest.manifest.revision(self, nodeorrev)
+
+    def baserevdiff(self, rev1, rev2):
+        return manifest.manifest.revdiff(self, rev1, rev2)
+
 class unionfilelog(unionrevlog, filelog.filelog):
     def __init__(self, opener, path, opener2, linkmapper, repo):
         filelog.filelog.__init__(self, opener, path)
         filelog2 = filelog.filelog(opener2, path)
         unionrevlog.__init__(self, opener, self.indexfile, filelog2,
                              linkmapper)
         self._repo = repo
 
+    def baserevision(self, nodeorrev):
+        return filelog.filelog.revision(self, nodeorrev)
+
+    def baserevdiff(self, rev1, rev2):
+        return filelog.filelog.revdiff(self, rev1, rev2)
+
     def _file(self, f):
         self._repo.file(f)
 
 class unionpeer(localrepo.localpeer):
     def canpush(self):
         return False
 
 class unionrepository(localrepo.localrepository):
     def __init__(self, ui, path, path2):
         localrepo.localrepository.__init__(self, ui, path)
         self.ui.setconfig('phases', 'publish', False)
 
         self._url = 'union:%s+%s' % (util.expandpath(path),
                                      util.expandpath(path2))
         self.repo2 = localrepo.localrepository(ui, path2)
 
     @localrepo.unfilteredpropertycache
     def changelog(self):
         return unionchangelog(self.sopener, self.repo2.sopener)
 
     def _clrev(self, rev2):
         """map from repo2 changelog rev to temporary rev in self.changelog"""
         node = self.repo2.changelog.node(rev2)
         return self.changelog.rev(node)
 
     @localrepo.unfilteredpropertycache
     def manifest(self):
         return unionmanifest(self.sopener, self.repo2.sopener,
                              self._clrev)
 
     def url(self):
         return self._url
 
     def file(self, f):
         return unionfilelog(self.sopener, f, self.repo2.sopener,
                             self._clrev, self)
 
     def close(self):
         self.repo2.close()
 
     def cancopy(self):
         return False
 
     def peer(self):
         return unionpeer(self)
 
     def getcwd(self):
         return os.getcwd() # always outside the repo
 
 def instance(ui, path, create):
     if create:
         raise util.Abort(_('cannot create new union repository'))
     parentpath = ui.config("bundle", "mainreporoot", "")
     if not parentpath:
         # try to find the correct path to the working directory repo
         parentpath = cmdutil.findrepo(os.getcwd())
         if parentpath is None:
             parentpath = ''
     if parentpath:
         # Try to make the full path relative so we get a nice, short URL.
         # In particular, we don't want temp dir names in test outputs.
         cwd = os.getcwd()
         if parentpath == cwd:
             parentpath = ''
         else:
             cwd = os.path.join(cwd,'')
             if parentpath.startswith(cwd):
                 parentpath = parentpath[len(cwd):]
     if path.startswith('union:'):
         s = path.split(":", 1)[1].split("+", 1)
         if len(s) == 1:
             repopath, repopath2 = parentpath, s[0]
         else:
             repopath, repopath2 = s
     else:
         repopath, repopath2 = parentpath, path
     return unionrepository(ui, repopath, repopath2)