Adding session-only localStorage.

content/browser/in_process_webkit/dom_storage_message_filter.cc

Index: content/browser/in_process_webkit/dom_storage_message_filter.cc
diff --git a/content/browser/in_process_webkit/dom_storage_message_filter.cc b/content/browser/in_process_webkit/dom_storage_message_filter.cc
index 8a327131b99001bd5d30d8ddb374605de9c8408c..50b611ea5d4175adbd3407eb32fe729a731aa1dd 100644
--- a/content/browser/in_process_webkit/dom_storage_message_filter.cc
+++ b/content/browser/in_process_webkit/dom_storage_message_filter.cc
@@ -83,7 +83,8 @@ bool DOMStorageMessageFilter::OnMessageReceived(const IPC::Message& message,
                                                 bool* message_was_ok) {
   bool handled = true;
   IPC_BEGIN_MESSAGE_MAP_EX(DOMStorageMessageFilter, message, *message_was_ok)
-    IPC_MESSAGE_HANDLER(DOMStorageHostMsg_StorageAreaId, OnStorageAreaId)
+    IPC_MESSAGE_HANDLER_DELAY_REPLY(
+        DOMStorageHostMsg_StorageAreaId, OnStorageAreaId)
     IPC_MESSAGE_HANDLER(DOMStorageHostMsg_Length, OnLength)
     IPC_MESSAGE_HANDLER(DOMStorageHostMsg_Key, OnKey)
     IPC_MESSAGE_HANDLER(DOMStorageHostMsg_GetItem, OnGetItem)
@@ -100,6 +101,19 @@ void DOMStorageMessageFilter::OnDestruct() const {
   BrowserThread::DeleteOnIOThread::Destruct(this);
 }
 
+void DOMStorageMessageFilter::OnGotStorageArea(DOMStorageArea* storage_area,
+                                               IPC::Message* reply_msg) {
+  if (storage_area) {
+    DOMStorageHostMsg_StorageAreaId::WriteReplyParams(reply_msg,
+                                                      storage_area->id());
+  } else {
+    DOMStorageHostMsg_StorageAreaId::WriteReplyParams(
+        reply_msg,
+        DOMStorageContext::kInvalidStorageId);
+  }
+  Send(reply_msg);
+}
+
 void DOMStorageMessageFilter::OverrideThreadForMessage(

[michaeln, 2011/07/30 16:49:24]

This additional thread context switching (from IO to WEBKIT, ,back to IO, back
to WEBKIT, then back to IO) is kind of going in circles. The point of the
OverrideThreadForMessage stuff was to simplify and streamline handling of
messages on other threads. But now that the DOMStorageHostMsg_StorageAreaId does
require processing on the IO thread, it probably would be cleaner and more
straightforward to not override the thread for that particular message.

void DOMStorageMessageFilter::OnStorageAreaId(int64 namespace_id,
                                              const string16& origin,
                                              IPC::Message* reply_msg) {
  // Initiate handling on the IO thread to get the content setting value.
  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
  bool content_setting_value = // get setting for this origin
  // Do the bulk of the work on the webkit thread.
  PostTask(OnStorageAreaIdWebKitThread,
           namespace_id, origin, content_setting_value , reply_msg);
}

void DOMStorageMessageFilter::OnStorageAreaIdWebKitThread(
                                              int64 namespace_id,
                                              const string16& origin,
                                              bool content_setting_value ,
                                              IPC::Message* reply_msg) {
  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::WEBKIT));
  DOMStorageNamespace* storage_namespace =
      Context()->GetStorageNamespace(namespace_id, content_setting_value ,
true);
  ...
  DOMStorageHostMsg_StorageAreaId::WriteReplyParams(reply_msg, area_id);
  Send(reply_msg);
}

wdyt?

[marja, 2011/08/01 09:41:27]

Done.

Thanks for the tip, this made the code a lot simpler.

     const IPC::Message& message,
     BrowserThread::ID* thread) {
@@ -109,17 +123,22 @@ void DOMStorageMessageFilter::OverrideThreadForMessage(
 
 void DOMStorageMessageFilter::OnStorageAreaId(int64 namespace_id,
                                               const string16& origin,
-                                              int64* storage_area_id) {
+                                              IPC::Message* reply_msg) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::WEBKIT));
 
   DOMStorageNamespace* storage_namespace =
       Context()->GetStorageNamespace(namespace_id, true);
   if (!storage_namespace) {
-    *storage_area_id = DOMStorageContext::kInvalidStorageId;
+    OnGotStorageArea(NULL, reply_msg);
     return;
   }
-  DOMStorageArea* storage_area = storage_namespace->GetStorageArea(origin);
-  *storage_area_id = storage_area->id();
+  DOMStorageArea* storage_area = storage_namespace->GetStorageArea(origin,
+                                                                   this,
+                                                                   reply_msg);
+  if (storage_area != NULL) {
+    OnGotStorageArea(storage_area, reply_msg);
+  }
+  // Else continues in OnGotStorageArea asynchronously.
 }
 
 void DOMStorageMessageFilter::OnLength(int64 storage_area_id,