[PATCH] lfs: register the flag processors per repository

[Matt Harbison]

# HG changeset patch
# User Matt Harbison <matt_harbison at yahoo.com>
# Date 1538626646 14400
#      Thu Oct 04 00:17:26 2018 -0400
# Node ID e010a7be6dc96ea7d48be81a7c5e8a8ed8bf6c31
# Parent  7a347d362a455d84bccf34347171d89724b9c9df
lfs: register the flag processors per repository

Previously, enabling the extension for any repo in commandserver or hgweb would
enable the flags on all repos.  Since localrepo.resolverevlogstorevfsoptions()
is called so early, the svfs option needs to be forced on later in reposetup()
to handle the case where the extension loads, but no lfs requirement has been
set.  That way, the flags processor is enabled when committing or unbundling.
This will also ensure that the flags processor is available on all revlogs in a
long running process.

I'm not sure if we need a formal API to add options like this- narrow doesn't
seem to need it.  I'm also not sure if REPO_FEATURE_LFS should just be added
unconditionally in reposetup()- it's easy enough to check the requirements to
see if a blob was actually committed.

diff --git a/hgext/lfs/__init__.py b/hgext/lfs/__init__.py
--- a/hgext/lfs/__init__.py
+++ b/hgext/lfs/__init__.py
@@ -218,6 +218,7 @@ def reposetup(ui, repo):
 
     repo.svfs.lfslocalblobstore = blobstore.local(repo)
     repo.svfs.lfsremoteblobstore = blobstore.remote(repo)
+    repo.svfs.options[b'enableextstored'] = True
 
     class lfsrepo(repo.__class__):
         @localrepo.unfilteredmethod
@@ -334,14 +335,9 @@ def extsetup(ui):
     wrapfunction(context.basefilectx, 'isbinary', wrapper.filectxisbinary)
     context.basefilectx.islfs = wrapper.filectxislfs
 
-    revlog.addflagprocessor(
-        revlog.REVIDX_EXTSTORED,
-        (
-            wrapper.readfromstore,
-            wrapper.writetostore,
-            wrapper.bypasscheckhash,
-        ),
-    )
+    wrapfunction(revlog, 'extstoredrawprocessor', wrapper.bypasscheckhash)
+    wrapfunction(revlog, 'extstoredreadprocessor', wrapper.readfromstore)
+    wrapfunction(revlog, 'extstoredwriteprocessor', wrapper.writetostore)
 
     scmutil.fileprefetchhooks.add('lfs', wrapper._prefetchfiles)
 
diff --git a/hgext/lfs/wrapper.py b/hgext/lfs/wrapper.py
--- a/hgext/lfs/wrapper.py
+++ b/hgext/lfs/wrapper.py
@@ -50,10 +50,10 @@ def _capabilities(orig, repo, proto):
         caps.append('lfs')
     return caps
 
-def bypasscheckhash(self, text):
+def bypasscheckhash(orig, self, text):
     return False
 
-def readfromstore(self, text):
+def readfromstore(orig, self, text):
     """Read filelog content from local blobstore transform for flagprocessor.
 
     Default tranform for flagprocessor, returning contents from blobstore.
@@ -81,7 +81,7 @@ def readfromstore(self, text):
 
     return (text, True)
 
-def writetostore(self, text):
+def writetostore(orig, self, text):
     # hg filelog metadata (includes rename, etc)
     hgmeta, offset = storageutil.parsemeta(text)
     if offset and offset > 0:
diff --git a/mercurial/localrepo.py b/mercurial/localrepo.py
--- a/mercurial/localrepo.py
+++ b/mercurial/localrepo.py
@@ -763,6 +763,9 @@ def resolverevlogstorevfsoptions(ui, req
         if r.startswith(b'exp-compression-'):
             options[b'compengine'] = r[len(b'exp-compression-'):]
 
+    if b'lfs' in requirements:
+        options[b'enableextstored'] = True
+
     if repository.NARROW_REQUIREMENT in requirements:
         options[b'enableellipsis'] = True
 
diff --git a/mercurial/revlog.py b/mercurial/revlog.py
--- a/mercurial/revlog.py
+++ b/mercurial/revlog.py
@@ -110,6 +110,26 @@ parsers = policy.importmod(r'parsers')
     REVIDX_ISCENSORED: None,
 }
 
+# Flag processors for REVIDX_EXTSTORED.
+def extstoredreadprocessor(rl, text):
+    raise error.ProgrammingError(b'extstored flags processor enabled without'
+                                 b' wrapping processor function')
+
+def extstoredwriteprocessor(rl, text):
+    raise error.ProgrammingError(b'extstored flags processor enabled without'
+                                 b' wrapping processor function')
+
+def extstoredrawprocessor(rl, text):
+    raise error.ProgrammingError(b'extstored flags processor enabled without'
+                                 b' wrapping processor function')
+
+# Lambdas are needed here so that these methods can be wrapped by lfs.
+extstoredprocessor = (
+    lambda rl, text: extstoredreadprocessor(rl, text),
+    lambda rl, text: extstoredwriteprocessor(rl, text),
+    lambda rl, text: extstoredrawprocessor(rl, text),
+)
+
 # Flag processors for REVIDX_ELLIPSIS.
 def ellipsisreadprocessor(rl, text):
     return text, False
@@ -405,6 +425,8 @@ class revlog(object):
                 self._srdensitythreshold = opts['sparse-read-density-threshold']
             if 'sparse-read-min-gap-size' in opts:
                 self._srmingapsize = opts['sparse-read-min-gap-size']
+            if opts.get('enableextstored'):
+                self._flagprocessors[REVIDX_EXTSTORED] = extstoredprocessor
             if opts.get('enableellipsis'):
                 self._flagprocessors[REVIDX_ELLIPSIS] = ellipsisprocessor