Extensions Docs Server: Efficient MemcacheFileSystem

chrome/common/extensions/docs/server2/handler.py

 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import logging
 import os
 import sys
 
 from appengine_wrappers import webapp
 from appengine_wrappers import memcache
@@ skipping 14 matching lines @@
 from subversion_file_system import SubversionFileSystem
 from template_data_source import TemplateDataSource
 from appengine_url_fetcher import AppEngineUrlFetcher
 
 # The branch that the server will default to when no branch is specified in the
 # URL. This is necessary because it is not possible to pass flags to the script
 # handler.
 DEFAULT_BRANCH = 'local'
 
 SVN_URL = 'http://src.chromium.org/chrome'
+VIEWVC_URL = 'http://src.chromium.org/viewvc/chrome'
 TRUNK_URL = SVN_URL + '/trunk'
 BRANCH_URL = SVN_URL + '/branches'
 
 OMAHA_PROXY_URL = 'http://omahaproxy.appspot.com/json'
 BRANCH_UTILITY_MEMCACHE = AppEngineMemcache('branch_utility')
 BRANCH_UTILITY = BranchUtility(OMAHA_PROXY_URL,
                                DEFAULT_BRANCH,
                                AppEngineUrlFetcher(''),
                                BRANCH_UTILITY_MEMCACHE)
 
@@ skipping 10 matching lines @@
 
 # Global cache of instances because Handler is recreated for every request.
 SERVER_INSTANCES = {}
 
 def _GetInstanceForBranch(branch, local_path):
   if branch in SERVER_INSTANCES:
     return SERVER_INSTANCES[branch]
   if branch == 'local':
     file_system = LocalFileSystem(local_path)
   else:
-    fetcher = AppEngineUrlFetcher(
-        _GetURLFromBranch(branch) + '/' + EXTENSIONS_PATH)
-    file_system = MemcacheFileSystem(SubversionFileSystem(fetcher),
-                                     AppEngineMemcache(branch))
+    svn_url = _GetURLFromBranch(branch) + '/' + EXTENSIONS_PATH
+    stat_fetcher = AppEngineUrlFetcher(svn_url.replace(SVN_URL, VIEWVC_URL))
+    fetcher = AppEngineUrlFetcher(svn_url)
+    file_system = MemcacheFileSystem(
+        SubversionFileSystem(fetcher, stat_fetcher),
+        AppEngineMemcache(branch))
 
   cache_builder = FileSystemCache.Builder(file_system)
   api_list_data_source = APIListDataSource(cache_builder,
                                            file_system,
                                            API_PATH,
                                            PUBLIC_TEMPLATE_PATH)
   intro_data_source = IntroDataSource(cache_builder,
                                       [INTRO_PATH, ARTICLE_PATH])
   samples_data_source_factory = SamplesDataSource.Factory(branch,
                                                           file_system,
@@ skipping 55 matching lines @@
       self._NavigateToPath('stable/extensions/samples.html')
       return
 
     # Redirect paths like "directory" to "directory/". This is so relative file
     # paths will know to treat this as a directory.
     if os.path.splitext(path)[1] == '' and path[-1] != '/':
       self.redirect(path + '/')
     path = path.replace('/chrome/', '')
     path = path.strip('/')
     self._NavigateToPath(path)