Refactor PPAPI proxy resource handling to maintain which host they came from,...

ppapi/proxy/plugin_resource_tracker.h

 // Copyright (c) 2011 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_PLUGIN_RESOURCE_TRACKER_H_
 #define PPAPI_PROXY_PLUGIN_RESOURCE_TRACKER_H_
 
 #include <map>
+#include <utility>
 
 #include "base/linked_ptr.h"
 #include "ppapi/c/pp_completion_callback.h"
+#include "ppapi/c/pp_instance.h"
 #include "ppapi/c/pp_stdint.h"
 #include "ppapi/c/pp_resource.h"
 #include "ppapi/c/pp_var.h"
+#include "ppapi/proxy/host_resource.h"
 
 template<typename T> struct DefaultSingletonTraits;
 
 namespace pp {
 namespace proxy {
 
 class PluginDispatcher;
 class PluginResource;
 
 class PluginResourceTracker {
  public:
+  // Called by tests that want to specify a specific ResourceTracker. This
+  // allows them to use a unique one each time and avoids singletons sticking
+  // around across tests.
+  static void SetInstanceForTest(PluginResourceTracker* tracker);
+
   // Returns the global singleton resource tracker for the plugin.
   static PluginResourceTracker* GetInstance();
 
   // Returns the object associated with the given resource ID, or NULL if
   // there isn't one.
   PluginResource* GetResourceObject(PP_Resource pp_resource);
 
-  void AddResource(PP_Resource pp_resource, linked_ptr<PluginResource> object);
+  // Adds the given resource object to the tracked list, and returns the
+  // plugin-local PP_Resource ID that identifies the resource. Note that this
+  // PP_Resource is not valid to send to the host, use
+  // PluginResource.host_resource() to get that.
+  PP_Resource AddResource(linked_ptr<PluginResource> object);
 
   void AddRefResource(PP_Resource resource);
   void ReleaseResource(PP_Resource resource);
 
-  // Checks if the resource just returned from the renderer is already
-  // tracked by the plugin side and adjusts the refcounts if so.
-  //
-  // When the browser returns a PP_Resource, it could be a new one, in which
-  // case the proxy wants to create a corresponding object and call
-  // AddResource() on it. However, if the resouce is already known, then the
-  // refcount needs to be adjusted in both the plugin and the renderer side
-  // and no such object needs to be created.
-  //
-  // Returns true if the resource was previously known. The refcount will be
-  // fixed up such that it's ready to use by the plugin. A proxy can then
-  // just return the resource without doing any more work.
-  //
-  // Typical usage:
-  //
-  //   PP_Resource result;
-  //   dispatcher->Send(new MyMessage(..., &result));
-  //   if (PluginResourceTracker::GetInstance()->
-  //           PreparePreviouslyTrackedResource(result))
-  //     return result;
-  //   ... create resource object ...
-  //   PluginResourceTracker::GetInstance()->AddResource(result, object);
-  //   return result;
-  bool PreparePreviouslyTrackedResource(PP_Resource resource);
+  // Given a host resource, maps it to an existing plugin resource ID if it
+  // exists, or returns 0 on failure.
+  PP_Resource PluginResourceForHostResource(
+      const HostResource& resource) const;
 
  private:
   friend struct DefaultSingletonTraits<PluginResourceTracker>;
+  friend class PluginResourceTrackerTest;
+  friend class PluginProxyTest;
 
   PluginResourceTracker();
   ~PluginResourceTracker();
 
   struct ResourceInfo {
     ResourceInfo();
     ResourceInfo(int ref_count, linked_ptr<PluginResource> r);
     ResourceInfo(const ResourceInfo& other);
     ~ResourceInfo();
 
     ResourceInfo& operator=(const ResourceInfo& other);
 
     int ref_count;
     linked_ptr<PluginResource> resource;  // May be NULL.
   };
 
   void ReleasePluginResourceRef(const PP_Resource& var,
                                 bool notify_browser_on_release);
 
   // Sends a ReleaseResource message to the host corresponding to the given
   // resource.
   void SendReleaseResourceToHost(PP_Resource resource_id,
                                  PluginResource* resource);
 
+  // Map of plugin resource IDs to the information tracking that resource.
   typedef std::map<PP_Resource, ResourceInfo> ResourceMap;
   ResourceMap resource_map_;
+
+  // Map of host instance/resource pairs to a plugin resource ID.
+  typedef std::map<HostResource, PP_Resource> HostResourceMap;
+  HostResourceMap host_resource_map_;
+
+  // Tracks the last ID we've sent out as a plugin resource so we don't send
+  // duplicates.
+  PP_Resource last_resource_id_;
+
+  DISALLOW_COPY_AND_ASSIGN(PluginResourceTracker);
 };
 
 }  // namespace proxy
 }  // namespace pp
 
 #endif  // PPAPI_PROXY_PLUGIN_RESOURCE_TRACKER_H_