PPAPI: Make blocking completion callbacks work.

ppapi/proxy/ppb_network_monitor_private_proxy.cc

 // 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.
 
 #include "ppapi/proxy/ppb_network_monitor_private_proxy.h"
 
 #include "ppapi/proxy/enter_proxy.h"
 #include "ppapi/proxy/plugin_proxy_delegate.h"
 #include "ppapi/proxy/ppapi_messages.h"
+#include "ppapi/shared_impl/proxy_lock.h"
 #include "ppapi/thunk/ppb_network_monitor_private_api.h"
 
 namespace ppapi {
 namespace proxy {
 
 class PPB_NetworkMonitor_Private_Proxy::NetworkMonitor
     : public Resource,
       public thunk::PPB_NetworkMonitor_Private_API,
       public base::SupportsWeakPtr<
           PPB_NetworkMonitor_Private_Proxy::NetworkMonitor> {
@@ skipping 12 matching lines @@
     proxy_->OnNetworkMonitorDeleted(this, pp_instance());
   }
 
 
   // Resource overrides.
   virtual ppapi::thunk::PPB_NetworkMonitor_Private_API*
   AsPPB_NetworkMonitor_Private_API() OVERRIDE {
     return this;
   }
 
-  void OnNetworkListReceived(const scoped_refptr<NetworkListStorage>& list) {
+  // This is invoked when a network list is received for this monitor (either
+  // initially or on a change). It acquires the ProxyLock inside because
+  // ObserverListThreadSafe does not support Bind/Closure, otherwise we would
+  // wrap the call with a lock using RunWhileLocked.
+  void OnNetworkListReceivedLocks(
+      const scoped_refptr<NetworkListStorage>& list) {
+    ProxyAutoLock lock;
     PP_Resource list_resource =
         PPB_NetworkList_Private_Shared::Create(
             OBJECT_IS_PROXY, pp_instance(), list);
     CallWhileUnlocked(callback_, user_data_, list_resource);
   }
 
  private:
   PPB_NetworkMonitor_Private_Proxy* proxy_;
   PPB_NetworkMonitor_Callback callback_;
   void* user_data_;
@@ skipping 10 matching lines @@
 
 PPB_NetworkMonitor_Private_Proxy::~PPB_NetworkMonitor_Private_Proxy() {
   monitors_->AssertEmpty();
 }
 
 // static
 PP_Resource PPB_NetworkMonitor_Private_Proxy::CreateProxyResource(
     PP_Instance instance,
     PPB_NetworkMonitor_Callback callback,
     void* user_data) {
+  // TODO(dmichael): Check that this thread has a valid message loop associated
+  //                 with it.
   if (!callback)
     return 0;
 
   PluginDispatcher* dispatcher = PluginDispatcher::GetForInstance(instance);
   if (!dispatcher)
     return 0;
   PPB_NetworkMonitor_Private_Proxy* proxy =
       static_cast<PPB_NetworkMonitor_Private_Proxy*>(
           dispatcher->GetInterfaceProxy(kApiID));
   if (!proxy)
     return 0;
 
   scoped_refptr<NetworkMonitor> result(
       new NetworkMonitor(instance, proxy, callback, user_data));
   proxy->monitors_->AddObserver(result.get());
 
   proxy->monitors_count_++;
   if (proxy->monitors_count_ == 1) {
     // If that is the first network monitor then send Start message.
     PluginGlobals::Get()->plugin_proxy_delegate()->SendToBrowser(
         new PpapiHostMsg_PPBNetworkMonitor_Start(
             dispatcher->plugin_dispatcher_id()));
 
     // We could have received network list message after sending the
     // previous Stop message. This list is stale now, so reset it
     // here.
     proxy->current_list_ = NULL;
   } else if (proxy->current_list_.get()) {
-    MessageLoop::current()->PostTask(FROM_HERE, RunWhileLocked(base::Bind(
-        &NetworkMonitor::OnNetworkListReceived,
-        result->AsWeakPtr(), proxy->current_list_)));
+    MessageLoop::current()->PostTask(FROM_HERE, base::Bind(
+        &NetworkMonitor::OnNetworkListReceivedLocks,
+        result->AsWeakPtr(), proxy->current_list_));
   }
 
   return result->GetReference();
 }
 
 bool PPB_NetworkMonitor_Private_Proxy::OnMessageReceived(
     const IPC::Message& msg) {
   bool handled = true;
   IPC_BEGIN_MESSAGE_MAP(PPB_NetworkMonitor_Private_Proxy, msg)
     IPC_MESSAGE_HANDLER(PpapiMsg_PPBNetworkMonitor_NetworkList,
                         OnPluginMsgNetworkList)
     IPC_MESSAGE_UNHANDLED(handled = false)
   IPC_END_MESSAGE_MAP()
   return handled;
 }
 
 void PPB_NetworkMonitor_Private_Proxy::OnPluginMsgNetworkList(
     uint32 plugin_dispatcher_id,
     const ppapi::NetworkList& list) {
   scoped_refptr<NetworkListStorage> list_storage(new NetworkListStorage(list));
   current_list_ = list_storage;
-  monitors_->Notify(&NetworkMonitor::OnNetworkListReceived, list_storage);
+  monitors_->Notify(&NetworkMonitor::OnNetworkListReceivedLocks, list_storage);
 }
 
 void PPB_NetworkMonitor_Private_Proxy::OnNetworkMonitorDeleted(
     NetworkMonitor* monitor,
     PP_Instance instance) {
   monitors_->RemoveObserver(monitor);
   monitors_count_--;
   if (monitors_count_ == 0) {
     // Send Stop message if that was the last NetworkMonitor.
     PluginDispatcher* dispatcher = PluginDispatcher::GetForInstance(instance);
     if (dispatcher) {
       PluginGlobals::Get()->plugin_proxy_delegate()->SendToBrowser(
           new PpapiHostMsg_PPBNetworkMonitor_Stop(
               dispatcher->plugin_dispatcher_id()));
     }
     current_list_ = NULL;
   }
 }
 
 }  // namespace proxy
 }  // namespace ppapi