[PATCH 3 of 5 V2] manifest: introduce manifestlog and manifestctx classes
Durham Goode
durham at fb.com
Tue Aug 23 13:30:24 EDT 2016
On 8/22/16 3:32 PM, Martin von Zweigbergk wrote:
> On Wed, Aug 17, 2016 at 2:07 PM, Durham Goode <durham at fb.com> wrote:
>> # HG changeset patch
>> # User Durham Goode <durham at fb.com>
>> # Date 1471465513 25200
>> # Wed Aug 17 13:25:13 2016 -0700
>> # Node ID 00f8d3832aad368660c69eff4be3e03a5568aebe
>> # Parent 8ddbe86953023c40beb7be9dcb8025d1055813c5
>> manifest: introduce manifestlog and manifestctx classes
>>
>> This is the start of a large refactoring of the manifest class. It introduces
>> the new manifestlog and manifestctx classes which will represent the collection
>> of all manifests and individual instances, respectively.
>>
>> Future patches will begin to convert usages of repo.manifest to
>> repo.manifestlog, adding the necessary functionality to manifestlog and instance
>> as they are needed.
>>
>> diff --git a/mercurial/localrepo.py b/mercurial/localrepo.py
>> --- a/mercurial/localrepo.py
>> +++ b/mercurial/localrepo.py
>> @@ -504,6 +504,10 @@ class localrepository(object):
>> def manifest(self):
>> return manifest.manifest(self.svfs)
>>
>> + @storecache('00manifest.i')
>> + def manifestlog(self):
>> + return manifest.manifestlog(self.svfs, self.manifest)
>> +
>> @repofilecache('dirstate')
>> def dirstate(self):
>> return dirstate.dirstate(self.vfs, self.ui, self.root,
>> diff --git a/mercurial/manifest.py b/mercurial/manifest.py
>> --- a/mercurial/manifest.py
>> +++ b/mercurial/manifest.py
>> @@ -914,6 +914,70 @@ class manifestrevlog(revlog.revlog):
>> super(manifestrevlog, self).clearcaches()
>> self._fulltextcache.clear()
>>
>> +class manifestlog(object):
>> + """A collection class representing the collection of manifest snapshots
>> + referenced by commits in the repository.
>> +
>> + In this situation, 'manifest' refers to the abstract concept of a snapshot
>> + of the list of files in the given commit. Consumers of the output of this
>> + class do not care about the implementation details of the actual manifests
>> + they receive (i.e. tree or flat or lazily loaded, etc)."""
>> + def __init__(self, opener, oldmanifest):
>> + self._revlog = oldmanifest
>> +
>> + # We'll separate this into it's own cache once oldmanifest is no longer
>> + # used
>> + self._mancache = oldmanifest._mancache
>> +
>> + # _revlog is the same as _oldmanifest right now, but we eventually want
>> + # to delete _oldmanifest while still allowing manifestlog to access the
>> + # revlog specific apis.
>> + self._oldmanifest = oldmanifest
>> +
>> + def __getitem__(self, node):
>> + """Retrieves the manifest instance for the given node. Throws a KeyError
>> + if not found.
>> + """
>> + if (self._oldmanifest._treeondisk
>> + or self._oldmanifest._treeinmem):
>> + # TODO: come back and support tree manifests directly
>> + return self._oldmanifest.read(node)
>> +
>> + if node == revlog.nullid:
>> + return manifestdict()
>> + if node in self._mancache:
>> + cachemf = self._mancache[node]
>> + # The old manifest may put non-ctx manifests in the cache, so skip
>> + # those since they don't implement the full api.
>> + if isinstance(cachemf, manifestctx):
>> + return cachemf
>> +
>> + m = manifestctx(self._revlog, node)
>> + self._mancache[node] = m
>> + return m
>> +
>> +class manifestctx(manifestdict):
> Btw, I don't really like this inheritance. It feels like the context
> *has*, not *is*, a manifest (the revlog data). Will it make sense to
> drop the manifestdict and treemanifest classes at the end and just
> have the context objects that have both the data (manifest) and the
> metadata (p1 etc)?
No, we still use manifestdict and treemanifest to return transient
results (like diff results). We could probably remove this inheritance,
but it would make the migration a bit messier, since every place that
accesses a manifestdict would have to be replaced to access a
manifestctx and then fetch the dict out of it. I can look into it
though, because a future patch makes the dict contents lazy loaded and I
don't really like how it works.
>> + """A class representing a single revision of a manifest, including its
>> + contents, its parent revs, and its linkrev.
>> + """
>> + def __init__(self, revlog, node):
>> + self._revlog = revlog
>> +
>> + self._node = node
>> + self.p1, self.p2 = revlog.parents(node)
>> + rev = revlog.rev(node)
>> + self.linkrev = revlog.linkrev(rev)
>> +
>> + # This should eventually be made lazy loaded, so consumers can access
>> + # the node/p1/linkrev data without having to parse the whole manifest.
>> + data = revlog.revision(node)
>> + arraytext = array.array('c', data)
>> + revlog._fulltextcache[node] = arraytext
>> + super(manifestctx, self).__init__(data)
>> +
>> + def node(self):
>> + return self._node
>> +
>> class manifest(manifestrevlog):
>> def __init__(self, opener, dir='', dirlogcache=None):
>> '''The 'dir' and 'dirlogcache' arguments are for internal use by
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