D4386: manifest: proxy to revlog instance instead of inheriting

indygreg (Gregory Szorc) phabricator at mercurial-scm.org
Mon Aug 27 16:01:09 UTC 2018


indygreg created this revision.
Herald added a subscriber: mercurial-devel.
Herald added a reviewer: hg-reviewers.

REVISION SUMMARY
  Previously, manifestrevlog inherited revlog.revlog and therefore
  exposed all its APIs. This inevitably resulted in consumers calling
  low-level revlog APIs.
  
  As part of abstracting storage, we want to formalize the interface
  for manifest storage. The revlog API is much too large to define as
  the interface.
  
  Like we did for filelog, this commit divorces the manifest class
  from revlog so that we can standardize on a smaller API surface.
  
  The way I went about this commit was I broke the inheritance, ran
  tests, and added proxies until all tests passed. Like filelog, there
  are a handful of attributes that don't belong on the interface.
  And like filelog, we'll tease these out in the future.
  
  As part of this, we formalize an interface for manifest storage and
  add checks that manifestrevlog conforms to the interface.
  
  .. api:: manifest.manifestrevlog no longer inherits from revlog
  
    The manifestrevlog class now wraps a revlog instance instead of
    inheriting from revlog. Various attributes and methods on instances
    are no longer available.

REPOSITORY
  rHG Mercurial

REVISION DETAIL
  https://phab.mercurial-scm.org/D4386

AFFECTED FILES
  mercurial/manifest.py
  mercurial/repository.py
  tests/test-check-interfaces.py

CHANGE DETAILS

diff --git a/tests/test-check-interfaces.py b/tests/test-check-interfaces.py
--- a/tests/test-check-interfaces.py
+++ b/tests/test-check-interfaces.py
@@ -177,6 +177,7 @@
     ziverify.verifyClass(repository.imanifestrevisionwritable,
                          manifest.memtreemanifestctx)
     ziverify.verifyClass(repository.imanifestlog, manifest.manifestlog)
+    ziverify.verifyClass(repository.imanifeststorage, manifest.manifestrevlog)
 
     vfs = vfsmod.vfs(b'.')
     fl = filelog.filelog(vfs, b'dummy.i')
@@ -198,6 +199,9 @@
     # Conforms to imanifestdict.
     checkzobject(mctx.read())
 
+    mrl = manifest.manifestrevlog(vfs)
+    checkzobject(mrl)
+
     ziverify.verifyClass(repository.irevisiondelta,
                          revlog.revlogrevisiondelta)
     ziverify.verifyClass(repository.irevisiondeltarequest,
diff --git a/mercurial/repository.py b/mercurial/repository.py
--- a/mercurial/repository.py
+++ b/mercurial/repository.py
@@ -988,6 +988,166 @@
         Returns the binary node of the created revision.
         """
 
+class imanifeststorage(interfaceutil.Interface):
+    """Storage interface for manifest data."""
+
+    index = interfaceutil.Attribute(
+        """An ``ifilerevisionssequence`` instance.""")
+
+    indexfile = interfaceutil.Attribute(
+        """Path of revlog index file.
+
+        TODO this is revlog specific and should not be exposed.
+        """)
+
+    opener = interfaceutil.Attribute(
+        """VFS opener to use to access underlying files used for storage.
+
+        TODO this is revlog specific and should not be exposed.
+        """)
+
+    version = interfaceutil.Attribute(
+        """Revlog version number.
+
+        TODO this is revlog specific and should not be exposed.
+        """)
+
+    _generaldelta = interfaceutil.Attribute(
+        """Whether generaldelta storage is being used.
+
+        TODO this is revlog specific and should not be exposed.
+        """)
+
+    fulltextcache = interfaceutil.Attribute(
+        """Dict with cache of fulltexts.
+
+        TODO this doesn't feel appropriate for the storage interface.
+        """)
+
+    def __len__():
+        """Obtain the number of revisions stored for this manifest."""
+
+    def __iter__():
+        """Iterate over revision numbers for this manifest."""
+
+    def rev(node):
+        """Obtain the revision number given a binary node.
+
+        Raises ``error.LookupError`` if the node is not known.
+        """
+
+    def node(rev):
+        """Obtain the node value given a revision number.
+
+        Raises ``error.LookupError`` if the revision is not known.
+        """
+
+    def lookup(value):
+        """Attempt to resolve a value to a node.
+
+        Value can be a binary node, hex node, revision number, or a bytes
+        that can be converted to an integer.
+
+        Raises ``error.LookupError`` if a ndoe could not be resolved.
+
+        TODO this is only used by debug* commands and can probably be deleted
+        easily.
+        """
+
+    def parents(node):
+        """Returns a 2-tuple of parent nodes for a node.
+
+        Values will be ``nullid`` if the parent is empty.
+        """
+
+    def parentrevs(rev):
+        """Like parents() but operates on revision numbers."""
+
+    def linkrev(rev):
+        """Obtain the changeset revision number a revision is linked to."""
+
+    def revision(node, _df=None, raw=False):
+        """Obtain fulltext data for a node."""
+
+    def revdiff(rev1, rev2):
+        """Obtain a delta between two revision numbers.
+
+        The returned data is the result of ``bdiff.bdiff()`` on the raw
+        revision data.
+        """
+
+    def cmp(node, fulltext):
+        """Compare fulltext to another revision.
+
+        Returns True if the fulltext is different from what is stored.
+        """
+
+    def emitrevisiondeltas(requests):
+        """Produce ``irevisiondelta`` from ``irevisiondeltarequest``s.
+
+        See the documentation for ``ifiledata`` for more.
+        """
+
+    def addgroup(deltas, linkmapper, transaction, addrevisioncb=None):
+        """Process a series of deltas for storage.
+
+        See the documentation in ``ifilemutation`` for more.
+        """
+
+    def getstrippoint(minlink):
+        """Find minimum revision that must be stripped to strip a linkrev.
+
+        See the documentation in ``ifilemutation`` for more.
+        """
+
+    def strip(minlink, transaction):
+        """Remove storage of items starting at a linkrev.
+
+        See the documentation in ``ifilemutation`` for more.
+        """
+
+    def checksize():
+        """Obtain the expected sizes of backing files.
+
+        TODO this is used by verify and it should not be part of the interface.
+        """
+
+    def files():
+        """Obtain paths that are backing storage for this manifest.
+
+        TODO this is used by verify and there should probably be a better API
+        for this functionality.
+        """
+
+    def deltaparent(rev):
+        """Obtain the revision that a revision is delta'd against.
+
+        TODO delta encoding is an implementation detail of storage and should
+        not be exposed to the storage interface.
+        """
+
+    def clone(tr, dest, **kwargs):
+        """Clone this instance to another."""
+
+    def clearcaches(clear_persisted_data=False):
+        """Clear any caches associated with this instance."""
+
+    def dirlog(d):
+        """Obtain a manifest storage instance for a tree."""
+
+    def add(m, transaction, link, p1, p2, added, removed, readtree=None):
+        """Add a revision to storage.
+
+        ``m`` is an object conforming to ``imanifestdict``.
+
+        ``link`` is the linkrev revision number.
+
+        ``p1`` and ``p2`` are the parent revision numbers.
+
+        ``added`` and ``removed`` are iterables of added and removed paths,
+        respectively.
+        """
+
 class imanifestlog(interfaceutil.Interface):
     """Interface representing a collection of manifest snapshots.
 
diff --git a/mercurial/manifest.py b/mercurial/manifest.py
--- a/mercurial/manifest.py
+++ b/mercurial/manifest.py
@@ -1246,7 +1246,8 @@
             self.write()
         self._read = False
 
-class manifestrevlog(revlog.revlog):
+ at interfaceutil.implementer(repository.imanifeststorage)
+class manifestrevlog(object):
     '''A revlog that stores manifest texts. This is responsible for caching the
     full-text manifest contents.
     '''
@@ -1291,10 +1292,14 @@
         else:
             self._dirlogcache = {'': self}
 
-        super(manifestrevlog, self).__init__(opener, indexfile,
-                                             # only root indexfile is cached
-                                             checkambig=not bool(tree),
-                                             mmaplargeindex=True)
+        self._revlog = revlog.revlog(opener, indexfile,
+                                     # only root indexfile is cached
+                                     checkambig=not bool(tree),
+                                     mmaplargeindex=True)
+
+        self.index = self._revlog.index
+        self.version = self._revlog.version
+        self._generaldelta = self._revlog._generaldelta
 
     def _setupmanifestcachehooks(self, repo):
         """Persist the manifestfulltextcache on lock release"""
@@ -1323,7 +1328,7 @@
         return self._fulltextcache
 
     def clearcaches(self, clear_persisted_data=False):
-        super(manifestrevlog, self).clearcaches()
+        self._revlog.clearcaches()
         self._fulltextcache.clear(clear_persisted_data=clear_persisted_data)
         self._dirlogcache = {self._tree: self}
 
@@ -1350,9 +1355,10 @@
                                [(x, True) for x in removed])
 
             arraytext, deltatext = m.fastdelta(self.fulltextcache[p1], work)
-            cachedelta = self.rev(p1), deltatext
+            cachedelta = self._revlog.rev(p1), deltatext
             text = util.buffer(arraytext)
-            n = self.addrevision(text, transaction, link, p1, p2, cachedelta)
+            n = self._revlog.addrevision(text, transaction, link, p1, p2,
+                                         cachedelta)
         else:
             # The first parent manifest isn't already loaded, so we'll
             # just encode a fulltext of the manifest and pass that
@@ -1366,7 +1372,7 @@
                 arraytext = None
             else:
                 text = m.text()
-                n = self.addrevision(text, transaction, link, p1, p2)
+                n = self._revlog.addrevision(text, transaction, link, p1, p2)
                 arraytext = bytearray(text)
 
         if arraytext is not None:
@@ -1395,12 +1401,90 @@
                 n = m2.node()
 
         if not n:
-            n = self.addrevision(text, transaction, link, m1.node(), m2.node())
+            n = self._revlog.addrevision(text, transaction, link, m1.node(),
+                                         m2.node())
 
         # Save nodeid so parent manifest can calculate its nodeid
         m.setnode(n)
         return n
 
+    def __len__(self):
+        return len(self._revlog)
+
+    def __iter__(self):
+        return self._revlog.__iter__()
+
+    def rev(self, node):
+        return self._revlog.rev(node)
+
+    def node(self, rev):
+        return self._revlog.node(rev)
+
+    def lookup(self, value):
+        return self._revlog.lookup(value)
+
+    def parentrevs(self, rev):
+        return self._revlog.parentrevs(rev)
+
+    def parents(self, node):
+        return self._revlog.parents(node)
+
+    def linkrev(self, rev):
+        return self._revlog.linkrev(rev)
+
+    def checksize(self):
+        return self._revlog.checksize()
+
+    def revision(self, node, _df=None, raw=False):
+        return self._revlog.revision(node, _df=_df, raw=raw)
+
+    def revdiff(self, rev1, rev2):
+        return self._revlog.revdiff(rev1, rev2)
+
+    def cmp(self, node, text):
+        return self._revlog.cmp(node, text)
+
+    def deltaparent(self, rev):
+        return self._revlog.deltaparent(rev)
+
+    def emitrevisiondeltas(self, requests):
+        return self._revlog.emitrevisiondeltas(requests)
+
+    def addgroup(self, deltas, linkmapper, transaction, addrevisioncb=None):
+        return self._revlog.addgroup(deltas, linkmapper, transaction,
+                                     addrevisioncb=addrevisioncb)
+
+    def getstrippoint(self, minlink):
+        return self._revlog.getstrippoint(minlink)
+
+    def strip(self, minlink, transaction):
+        return self._revlog.strip(minlink, transaction)
+
+    def files(self):
+        return self._revlog.files()
+
+    def clone(self, tr, destrevlog, **kwargs):
+        if not isinstance(destrevlog, manifestrevlog):
+            raise error.ProgrammingError('expected manifestrevlog to clone()')
+
+        return self._revlog.clone(tr, destrevlog._revlog, **kwargs)
+
+    @property
+    def indexfile(self):
+        return self._revlog.indexfile
+
+    @indexfile.setter
+    def indexfile(self, value):
+        self._revlog.indexfile = value
+
+    @property
+    def opener(self):
+        return self._revlog.opener
+
+    @opener.setter
+    def opener(self, value):
+        self._revlog.opener = value
+
 @interfaceutil.implementer(repository.imanifestlog)
 class manifestlog(object):
     """A collection class representing the collection of manifest snapshots



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