Prevent Pepper plugin reentrncy for synchronous messages.

ppapi/proxy/host_dispatcher.h

 // Copyright (c) 2010 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_HOST_DISPATCHER_H_
 #define PPAPI_PROXY_HOST_DISPATCHER_H_
 
 #include <map>
 #include <string>
 #include <vector>
@@ skipping 41 matching lines @@
   // Returns the host's notion of our PP_Module. This will be different than
   // the plugin's notion of its PP_Module because the plugin process may be
   // used by multiple renderer processes.
   //
   // Use this value instead of a value from the plugin whenever talking to the
   // host.
   PP_Module pp_module() const { return pp_module_; }
 
   // Dispatcher overrides.
   virtual bool IsPlugin() const;
+  virtual bool Send(IPC::Message* msg);
 
   // IPC::Channel::Listener.
   virtual bool OnMessageReceived(const IPC::Message& msg);
   virtual void OnChannelError();
 
   // Proxied version of calling GetInterface on the plugin. This will check
   // if the plugin supports the given interface (with caching) and returns the
   // pointer to the proxied interface if it is supported. Returns NULL if the
   // given interface isn't supported by the plugin or the proxy.
   const void* GetProxiedInterface(const std::string& interface);
 
   // Returns the proxy object associated with the given interface ID, creating
   // it if necessary. This is used in cases where a proxy needs to access code
   // in the proxy for another interface. It's assumed that the interface always
   // exists, so this is only used for browser proxies.
   //
   // Will return NULL if an interface isn't supported.
   InterfaceProxy* GetOrCreatePPBInterfaceProxy(InterfaceID id);
 
+  // See the value below. Call this when processing a scripting message from
+  // the plugin that can be reentered.
+  void set_allow_plugin_reentrancy() {
+    allow_plugin_reentrancy_ = true;
+  }
+
   // Returns the proxy interface for talking to the implementation.
   const PPB_Proxy_Private* ppb_proxy() const { return ppb_proxy_; }
 
  private:
   friend class HostDispatcherTest;
 
   // Makes an instance of the given PPB interface proxy, storing it in the
   // target_proxies_ array. An proxy for this interface must not exist yet.
   InterfaceProxy* CreatePPBInterfaceProxy(const InterfaceProxy::Info* info);
 
   PP_Module pp_module_;
 
   enum PluginInterfaceSupport {
     INTERFACE_UNQUERIED = 0,  // Must be 0 so memset(0) will clear the list.
     INTERFACE_SUPPORTED,
     INTERFACE_UNSUPPORTED
   };
   PluginInterfaceSupport plugin_interface_support_[INTERFACE_ID_COUNT];
 
   // All target proxies currently created. These are ones that receive
   // messages. They are created on demand when we receive messages.
   scoped_ptr<InterfaceProxy> target_proxies_[INTERFACE_ID_COUNT];
 
   // Guaranteed non-NULL.
   const PPB_Proxy_Private* ppb_proxy_;
 
+  // Set to true when the plugin is in a state that it can be reentered by a
+  // sync message from the host. We allow reentrancy only when we're processing
+  // a sync message from the renderer that is a scripting command. When the
+  // plugin is in this state, it needs to accept reentrancy since scripting may
+  // ultimately call back into the plugin.
+  bool allow_plugin_reentrancy_;
+
   DISALLOW_COPY_AND_ASSIGN(HostDispatcher);
 };
 
 }  // namespace proxy
 }  // namespace pp
 
 #endif  // PPAPI_PROXY_HOST_DISPATCHER_H_