Bug 1168607 - Add a native Mercurial finder; r=glandium

The hglib Mercurial finder was nice. But it is somewhat slow, as it
involves a separate Mercurial process.

This commit introduces a native Mercurial finder that speaks directly
to a Mercurial repository instance. It is significantly faster.

The new code is isolated to its own file because it imports Mercurial
code, which is GPL.

--HG--
extra : commitid : 8CzDFt3lQmx
extra : rebase_source : 1540ad20d795086926b316612062e2a1f10c4958

python/mozbuild/mozpack/files.py

@@ -1013,7 +1013,7 @@ class MercurialRevisionFinder(BaseFinder):
 
         # Immediately populate the list of files in the repo since nearly every
         # operation requires this list.
-        out = self._client.rawcommand([b'files', b'--rev', self._rev])
+        out = self._client.rawcommand([b'files', b'--rev', str(self._rev)])
         for relpath in out.splitlines():
             self._files[relpath] = None
 

python/mozbuild/mozpack/hg.py

@@ -0,0 +1,93 @@
+# Copyright (C) 2015 Mozilla Contributors
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License
+# as published by the Free Software Foundation; either version 2
+# of the License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+#
+# As a special exception, the copyright holders of this code give you
+# permission to combine this code with the software known as 'mozbuild',
+# and to distribute those combinations without any restriction
+# coming from the use of this file. (The General Public License
+# restrictions do apply in other respects; for example, they cover
+# modification of the file, and distribution when not combined with
+# mozbuild.)
+#
+# If you modify this code, you may extend this exception to your
+# version of the code, but you are not obliged to do so. If you
+# do not wish to do so, delete this exception statement from your
+# version.
+
+import mercurial.error as error
+import mercurial.hg as hg
+import mercurial.ui as hgui
+
+from .files import (
+    BaseFinder,
+    MercurialFile,
+)
+import mozpack.path as mozpath
+
+
+# This isn't a complete implementation of BaseFile. But it is complete
+# enough for moz.build reading.
+class MercurialNativeFile(MercurialFile):
+    def __init__(self, data):
+        self.data = data
+
+    def read(self):
+        return self.data
+
+
+class MercurialNativeRevisionFinder(BaseFinder):
+    def __init__(self, repo, rev='.', recognize_repo_paths=False):
+        """Create a finder attached to a specific changeset.
+
+        Accepts a Mercurial localrepo and changectx instance.
+        """
+        if isinstance(repo, (str, unicode)):
+            path = repo
+            repo = hg.repository(hgui.ui(), repo)
+        else:
+            path = repo.root
+
+        super(MercurialNativeRevisionFinder, self).__init__(base=repo.root)
+
+        self._repo = repo
+        self._rev = rev
+        self._root = mozpath.normpath(path)
+        self._recognize_repo_paths = recognize_repo_paths
+
+    def _find(self, pattern):
+        if self._recognize_repo_paths:
+            raise NotImplementedError('cannot use find with recognize_repo_path')
+
+        return self._find_helper(pattern, self._repo[self._rev], self._get)
+
+    def get(self, path):
+        if self._recognize_repo_paths:
+            if not path.startswith(self._root):
+                raise ValueError('lookups in recognize_repo_paths mode must be '
+                                 'prefixed with repo path: %s' % path)
+            path = path[len(self._root) + 1:]
+
+        return self._get(path)
+
+    def _get(self, path):
+        if isinstance(path, unicode):
+            path = path.encode('utf-8', 'replace')
+
+        try:
+            fctx = self._repo.filectx(path, self._rev)
+            return MercurialNativeFile(fctx.data())
+        except error.LookupError:
+            return None

python/mozbuild/mozpack/test/test_files.py

@@ -33,6 +33,11 @@ try:
 except ImportError:
     hglib = None
 
+try:
+    from mozpack.hg import MercurialNativeRevisionFinder
+except ImportError:
+    MercurialNativeRevisionFinder = None
+
 from mozpack.mozjar import (
     JarReader,
     JarWriter,
@@ -1042,11 +1047,14 @@ class TestMercurialRevisionFinder(MatchTestTemplate, TestWithTmpDir):
     def do_check(self, pattern, result):
         do_check(self, self.finder, pattern, result)
 
+    def _get_finder(self, *args, **kwargs):
+        return MercurialRevisionFinder(*args, **kwargs)
+
     def test_default_revision(self):
         self.prepare_match_test()
         c = hglib.open(self.tmpdir)
         c.commit('initial commit')
-        self.finder = MercurialRevisionFinder(self.tmpdir)
+        self.finder = self._get_finder(self.tmpdir)
         self.do_match_test()
 
         self.assertIsNone(self.finder.get('does-not-exist'))
@@ -1069,13 +1077,13 @@ class TestMercurialRevisionFinder(MatchTestTemplate, TestWithTmpDir):
         # finding anything from the filesystem.
         c.rawcommand(['update', 'null'])
 
-        finder = MercurialRevisionFinder(self.tmpdir, rev='0')
+        finder = self._get_finder(self.tmpdir, 0)
         f = finder.get('foo')
         self.assertEqual(f.read(), 'foo initial')
         self.assertEqual(f.read(), 'foo initial', 'read again for good measure')
         self.assertIsNone(finder.get('bar'))
 
-        finder = MercurialRevisionFinder(self.tmpdir, rev='1')
+        finder = MercurialRevisionFinder(self.tmpdir, rev=1)
         f = finder.get('foo')
         self.assertEqual(f.read(), 'foo second')
         f = finder.get('bar')
@@ -1089,8 +1097,8 @@ class TestMercurialRevisionFinder(MatchTestTemplate, TestWithTmpDir):
         c.commit('initial')
         c.rawcommand(['update', 'null'])
 
-        finder = MercurialRevisionFinder(self.tmpdir, rev='0',
-                                         recognize_repo_paths=True)
+        finder = self._get_finder(self.tmpdir, 0,
+                                  recognize_repo_paths=True)
         with self.assertRaises(NotImplementedError):
             list(finder.find(''))
 
@@ -1104,5 +1112,11 @@ class TestMercurialRevisionFinder(MatchTestTemplate, TestWithTmpDir):
         self.assertEqual(f.read(), 'initial')
 
 
+@unittest.skipUnless(MercurialNativeRevisionFinder, 'hgnative not available')
+class TestMercurialNativeRevisionFinder(TestMercurialRevisionFinder):
+    def _get_finder(self, *args, **kwargs):
+        return MercurialNativeRevisionFinder(*args, **kwargs)
+
+
 if __name__ == '__main__':
     mozunit.main()