revlog: move censor logic out of censor extension
The censor extension is doing very low-level things with revlogs.
It is fundamentally impossible for this logic to remain in the censor
extension while support multiple storage backends: we need each
storage backend to implement censor in its own storage-specific
way.
This commit effectively moves the revlog-specific censoring code to
be a method of revlogs themselves.
We've defined a new API on the file storage interface for censoring
an individual node. Even though the current censoring code doesn't
use it, the API requires a transaction instance because it logically
makes sense for storage backends to require an active transaction
(which implies a held write lock) in order to rewrite storage.
After this commit, the censor extension has been reduced to
boilerplate precondition checking before invoking the generic
storage API.
I tried to keep the code as similar as possible. But some minor
changes were made:
* We use self._io instead of instantiating a new revlogio instance.
* We compare self.version against REVLOGV0 instead of != REVLOGV1
because presumably all future revlog versions will support censoring.
* We use self.opener instead of going through repo.svfs (we don't have
a handle on the repo instance from a revlog).
* "revlog" dropped
* Replace "flog" with "self".
Differential Revision: https://phab.mercurial-scm.org/D4656
#require test-repo pyflakes hg10
$ . "$TESTDIR/helpers-testrepo.sh"
run pyflakes on all tracked files ending in .py or without a file ending
(skipping binary file random-seed)
$ cat > test.py <<EOF
> print(undefinedname)
> EOF
$ pyflakes test.py 2>/dev/null | "$TESTDIR/filterpyflakes.py"
test.py:1: undefined name 'undefinedname'
$ cd "`dirname "$TESTDIR"`"
$ testrepohg locate 'set:**.py or grep("^#!.*python")' \
> -X hgext/fsmonitor/pywatchman \
> -X mercurial/pycompat.py -X contrib/python-zstandard \
> -X mercurial/thirdparty/cbor \
> -X mercurial/thirdparty/concurrent \
> -X mercurial/thirdparty/zope \
> 2>/dev/null \
> | xargs pyflakes 2>/dev/null | "$TESTDIR/filterpyflakes.py"