Extensions Docs Server: Efficient MemcacheFileSystem

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

Index: chrome/common/extensions/docs/server2/memcache_file_system.py
diff --git a/chrome/common/extensions/docs/server2/memcache_file_system.py b/chrome/common/extensions/docs/server2/memcache_file_system.py
index 5ac407237cabd5055aeee07a1def863a80b4d147..e46f8c91fa6fc50ded9c0de8053f46820b7d9275 100644
--- a/chrome/common/extensions/docs/server2/memcache_file_system.py
+++ b/chrome/common/extensions/docs/server2/memcache_file_system.py
@@ -23,8 +23,13 @@ class MemcacheFileSystem(FileSystem):
       self._memcache.Set(path,
                          stat_info.version,
                          memcache.MEMCACHE_FILE_SYSTEM_STAT)
+      if stat_info.child_versions is not None:
+        for child_path, child_version in stat_info.child_versions.iteritems():
+          self._memcache.Set(path.rsplit('/', 1)[0] + '/' + child_path,
+                             child_version,
+                             memcache.MEMCACHE_FILE_SYSTEM_STAT)
     else:
-      stat_info = self.StatInfo(version)
+      stat_info = self.StatInfo(version, None)
     return stat_info
 
   def Read(self, paths, binary=False):
@@ -45,12 +50,13 @@ class MemcacheFileSystem(FileSystem):
         uncached.append(path)
         continue
       result[path] = data
-    new_items = self._file_system.Read(uncached, binary=binary).Get()
-    for item in new_items:
-      version = self.Stat(item).version
-      value = new_items[item]
-      self._memcache.Set(item,
-                         (value, version),
-                         memcache.MEMCACHE_FILE_SYSTEM_READ)
-      result[item] = value
+    if uncached:
+      new_items = self._file_system.Read(uncached, binary=binary).Get()

[not at google - send to devlin, 2012/08/13 23:02:14]

Add a TODO here,

TODO(cduvall): if there are uncached items we should return an asynchronous
future.

there might be an appropriate bug filed about that somewhere. Seems kind of
important to fix actually, since this would prevent us being able to download
things in parallel.

[cduvall, 2012/08/14 18:15:00]

Done.

+      for item in new_items:
+        version = self.Stat(item).version
+        value = new_items[item]
+        self._memcache.Set(item,
+                           (value, version),
+                           memcache.MEMCACHE_FILE_SYSTEM_READ)
+        result[item] = value
     return Future(value=result)