1 files changed, 43 insertions, 5 deletions

diff --git a/webkit/glue/plugins/pepper_resource.h b/webkit/glue/plugins/pepper_resource.h
index 4e347cb..417a06b 100644
--- a/webkit/glue/plugins/pepper_resource.h
+++ b/webkit/glue/plugins/pepper_resource.h
@@ -5,6 +5,7 @@
 #ifndef WEBKIT_GLUE_PLUGINS_PEPPER_RESOURCE_H_
 #define WEBKIT_GLUE_PLUGINS_PEPPER_RESOURCE_H_
 
+#include "base/logging.h"
 #include "base/basictypes.h"
 #include "base/ref_counted.h"
 #include "third_party/ppapi/c/pp_resource.h"
@@ -29,8 +30,8 @@ class Widget;
 
 class Resource : public base::RefCountedThreadSafe<Resource> {
  public:
-  explicit Resource(PluginModule* module);
-  virtual ~Resource();
+  explicit Resource(PluginModule* module)  : resource_id_(0), module_(module) {}
+  virtual ~Resource() {}
 
   // Returns NULL if the resource is invalid or is a different type.
   template<typename T>
@@ -39,8 +40,6 @@ class Resource : public base::RefCountedThreadSafe<Resource> {
     return resource ? resource->Cast<T>() : NULL;
   }
 
-  PP_Resource GetResource() const;
-
   PluginModule* module() const { return module_; }
 
   // Cast the resource into a specified type. This will return NULL if the
@@ -48,6 +47,27 @@ class Resource : public base::RefCountedThreadSafe<Resource> {
   // template call into As* functions.
   template <typename T> T* Cast() { return NULL; }
 
+  // Returns an resource id of this object. If the object doesn't have a
+  // resource id, new one is created with plugin refcount of 1. If it does,
+  // the refcount is incremented. Use this when you need to return a new
+  // reference to the plugin.
+  PP_Resource GetReference();
+
+  // When you need to ensure that a resource has a reference, but you do not
+  // want to increase the refcount (for example, if you need to call a plugin
+  // callback function with a reference), you can use this class. For example:
+  //
+  // plugin_callback(.., ScopedResourceId(resource).id, ...);
+  class ScopedResourceId {
+   public:
+    explicit ScopedResourceId(Resource* resource)
+        : id(resource->GetReference()) {}
+    ~ScopedResourceId() {
+      ResourceTracker::Get()->UnrefResource(id);
+    }
+    const PP_Resource id;
+  };
+
  private:
   // Type-specific getters for individual resource types. These will return
   // NULL if the resource does not match the specified type. Used by the Cast()
@@ -66,7 +86,25 @@ class Resource : public base::RefCountedThreadSafe<Resource> {
   virtual URLResponseInfo* AsURLResponseInfo() { return NULL; }
   virtual Widget* AsWidget() { return NULL; }
 
-  PluginModule* module_;  // Non-owning pointer to our module.
+ private:
+  // If referenced by a plugin, holds the id of this resource object. Do not
+  // access this member directly, because it is possible that the plugin holds
+  // no references to the object, and therefore the resource_id_ is zero. Use
+  // either GetReference() to obtain a new resource_id and increase the
+  // refcount, or TemporaryReference when you do not want to increase the
+  // refcount.
+  PP_Resource resource_id_;
+
+  // Non-owning pointer to our module.
+  PluginModule* module_;
+
+  // Called by the resource tracker when the last plugin reference has been
+  // dropped.
+  friend class ResourceTracker;
+  void StoppedTracking() {
+    DCHECK(resource_id_ != 0);
+    resource_id_ = 0;
+  }
 
   DISALLOW_COPY_AND_ASSIGN(Resource);
 };