PPAPI: Disallow blocking callbacks while handling a blocking message

ppapi/proxy/ppb_message_loop_proxy.h

 // 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.
 
 #ifndef PPAPI_PROXY_PPB_MESSAGE_LOOP_PROXY_H_
 #define PPAPI_PROXY_PPB_MESSAGE_LOOP_PROXY_H_
 
 #include "base/basictypes.h"
 #include "base/bind.h"
 #include "base/memory/ref_counted.h"
@@ skipping 30 matching lines @@
   static MessageLoopResource* GetCurrent();
   void DetachFromThread();
   bool is_main_thread_loop() const {
     return is_main_thread_loop_;
   }
 
   const scoped_refptr<base::MessageLoopProxy>& message_loop_proxy() {
     return loop_proxy_;
   }
 
+  void set_currently_handling_blocking_message(bool handling_blocking_message) {
+    currently_handling_blocking_message_ = handling_blocking_message;
+  }
+
  private:
   struct TaskInfo {
     tracked_objects::Location from_here;
     base::Closure closure;
     int64 delay_ms;
   };
 
   // Returns true if the object is associated with the current thread.
   bool IsCurrent() const;
 
+  // MessageLoopShared implementation.
+  //
   // Handles posting to the message loop if there is one, or the pending queue
   // if there isn't.
   // NOTE: The given closure will be run *WITHOUT* acquiring the Proxy lock.
   //       This only makes sense for user code and completely thread-safe
   //       proxy operations (e.g., MessageLoop::QuitClosure).
   virtual void PostClosure(const tracked_objects::Location& from_here,
                            const base::Closure& closure,
                            int64 delay_ms) OVERRIDE;
-
   virtual base::MessageLoopProxy* GetMessageLoopProxy() OVERRIDE;
+  virtual bool CurrentlyHandlingBlockingMessage() OVERRIDE;
 
   // TLS destructor function.
   static void ReleaseMessageLoop(void* value);
 
   // Created when we attach to the current thread, since MessageLoop assumes
   // that it's created on the thread it will run on. NULL for the main thread
   // loop, since that's owned by somebody else. This is needed for Run and Quit.
   // Any time we post tasks, we should post them using loop_proxy_.
   scoped_ptr<base::MessageLoop> loop_;
   scoped_refptr<base::MessageLoopProxy> loop_proxy_;
 
   // Number of invocations of Run currently on the stack.
   int nested_invocations_;
 
   // Set to true when the message loop is destroyed to prevent forther
   // posting of work.
   bool destroyed_;
 
   // Set to true if all message loop invocations should exit and that the
   // loop should be destroyed once it reaches the outermost Run invocation.
   bool should_destroy_;
 
   bool is_main_thread_loop_;
 
+  bool currently_handling_blocking_message_;
+
   // Since we allow tasks to be posted before the message loop is actually
   // created (when it's associated with a thread), we keep tasks posted here
   // until that happens. Once the loop_ is created, this is unused.
   std::vector<TaskInfo> pending_tasks_;
 
   DISALLOW_COPY_AND_ASSIGN(MessageLoopResource);
 };
 
 class PPB_MessageLoop_Proxy : public InterfaceProxy {
  public:
   explicit PPB_MessageLoop_Proxy(Dispatcher* dispatcher);
   virtual ~PPB_MessageLoop_Proxy();
 
   static const PPB_MessageLoop_1_0* GetInterface();
 
  private:
   DISALLOW_COPY_AND_ASSIGN(PPB_MessageLoop_Proxy);
 };
 
 }  // namespace proxy
 }  // namespace ppapi
 
 #endif  // PPAPI_PROXY_PPB_MESSAGE_LOOP_PROXY_H_