fastannotate: add hgweb support

Summary:
This adds fastannotate support for hgweb. There are some issues with "path"
handling, which will be addressed in follow up patches.

A minor change has been made in this patch to support revision numbers
(previously only global changeset hashes are supported).

Test Plan:
Run `hg serve --config fastannotate.hgweb=1` on the `hg-committed` repo, open
the following URL and confirm it's using fastannotate:
http://localhost:8000/annotate/9af6f8434430/mercurial/commands.py

Reviewers: #sourcecontrol, simonfar

Reviewed By: simonfar

Subscribers: simonfar, mjpieters

Differential Revision: https://phabricator.intern.facebook.com/D3993636

Signature: t1:3993636:1476026586:cb0628aa7107bdbfde852a6a1471f70dcb21a5ef

fastannotate/__init__.py

@@ -22,6 +22,11 @@ be faster than the vanilla 'annotate' if the cache is present.
     mainbranch = master
     # add a "fastannotate" command, and replace the default "annotate" command
     commands = fastannotate, annotate
+    # replace hgweb's annotate implementation (default: False)
+    # note: mainbranch should be set to a forward-only name, otherwise the
+    # linelog cache may be rebuilt frequently, which leads to errors and
+    # poor performance
+    hgweb = True
     # use unfiltered repo for better performance
     unfilteredrepo = True
     # sacrifice correctness in some cases for performance (default: False)
@@ -54,3 +59,7 @@ def uisetup(ui):
         else:
             raise hgerror.Abort(_('%s: invalid fastannotate.commands option')
                                 % name)
+    if ui.configbool('fastannotate', 'hgweb'):
+        # local import to avoid overhead of loading hgweb for non-hgweb usages
+        from fastannotate import hgwebsupport
+        hgwebsupport.replacehgwebannotate()

fastannotate/context.py

@@ -94,7 +94,7 @@ def resolvefctx(repo, rev, path, resolverev=False, adjustctx=None):
     is 'linkrev', trust the linkrev and do not adjust it. this is noticeably
     faster for big repos but is incorrect for some cases.
     """
-    if resolverev:
+    if resolverev and not isinstance(rev, int):
         ctx = _revsingle(repo, rev)
     else:
         ctx = repo[rev]
@@ -352,11 +352,12 @@ class _annotatecontext(object):
         """
         result = True
         f = None
-        if len(rev) == 20 and rev in self.revmap:
-            f = rev
-        elif len(rev) == 40 and node.bin(rev) in self.revmap:
-            f = node.bin(rev)
-        else:
+        if not isinstance(rev, int):
+            if len(rev) == 20 and rev in self.revmap:
+                f = rev
+            elif len(rev) == 40 and node.bin(rev) in self.revmap:
+                f = node.bin(rev)
+        if f is None:
             adjustctx = 'linkrev' if self._perfhack else True
             f = self._resolvefctx(rev, adjustctx=adjustctx, resolverev=True)
             result = f in self.revmap

fastannotate/hgwebsupport.py

@@ -0,0 +1,40 @@
+# Copyright 2016-present Facebook. All Rights Reserved.
+#
+# hgwebsupport: fastannotate support for hgweb
+#
+# This software may be used and distributed according to the terms of the
+# GNU General Public License version 2 or any later version.
+
+from __future__ import absolute_import
+
+from mercurial import (
+    extensions,
+    patch,
+)
+from mercurial.hgweb import webutil
+
+from fastannotate import context
+
+def _annotate(orig, fctx, ui):
+    diffopts = patch.difffeatureopts(ui, untrusted=True,
+                                     section='annotate', whitespace=True)
+    aopts = context.annotateopts(diffopts=diffopts)
+    master = ui.config('fastannotate', 'mainbranch', 'default')
+    with context.annotatecontext(fctx.repo(), fctx.path(), aopts) as ac:
+        # fastannotate returns: [(nodeid, linenum, path)], [linecontent]
+        annotated, contents = ac.annotate(fctx.rev(), master=master,
+                                          showpath=True, showlines=True)
+
+    # convert to what fctx.annotate returns: [((fctx, number), linecontent)]
+    fctxmap = {} # {(nodeid, path): fctx}
+    repo = fctx.repo()
+    results = []
+    for i, (hsh, linenum, path) in enumerate(annotated):
+        if (hsh, path) not in fctxmap:
+            fctxmap[(hsh, path)] = context.resolvefctx(repo, hsh, path)
+        results.append(((fctxmap[(hsh, path)], linenum), contents[i]))
+
+    return results
+
+def replacehgwebannotate():
+    extensions.wrapfunction(webutil, 'annotate', _annotate)