Simplfy Pepepr2 bolierplate code.

webkit/glue/plugins/pepper_resource.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 WEBKIT_GLUE_PLUGINS_PEPPER_RESOURCE_H_
 #define WEBKIT_GLUE_PLUGINS_PEPPER_RESOURCE_H_
 
 #include "base/basictypes.h"
 #include "base/ref_counted.h"
 #include "third_party/ppapi/c/pp_resource.h"
+#include "webkit/glue/plugins/pepper_resource_tracker.h"
 
 namespace pepper {
 
 class Buffer;
 class DeviceContext2D;
 class DirectoryReader;
 class FileChooser;
 class FileIO;
 class FileRef;
 class ImageData;
 class PluginModule;
 class URLLoader;
 class URLRequestInfo;
 class URLResponseInfo;
 
 class Resource : public base::RefCountedThreadSafe<Resource> {
  public:
   explicit Resource(PluginModule* module);
   virtual ~Resource();
 
+  // Returns NULL if the resource is invalid or is a different type.
+  template<typename T>
+  static scoped_refptr<T> GetAs(PP_Resource res) {
+    scoped_refptr<Resource> resource = ResourceTracker::Get()->GetResource(res);
+    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
+  // resource does not match the specified type. Specializations of this
+  // template call into As* functions.
+  template <typename T> T* Cast() { return NULL; }
+
+ private:
   // Type-specific getters for individual resource types. These will return
-  // NULL if the resource does not match the specified type.
+  // NULL if the resource does not match the specified type. Used by the Cast()
+  // function.
   virtual Buffer* AsBuffer() { return NULL; }
   virtual DeviceContext2D* AsDeviceContext2D() { return NULL; }
   virtual DirectoryReader* AsDirectoryReader() { return NULL; }
   virtual FileChooser* AsFileChooser() { return NULL; }
   virtual FileIO* AsFileIO() { return NULL; }
   virtual FileRef* AsFileRef() { return NULL; }
   virtual ImageData* AsImageData() { return NULL; }
   virtual URLLoader* AsURLLoader() { return NULL; }
   virtual URLRequestInfo* AsURLRequestInfo() { return NULL; }
   virtual URLResponseInfo* AsURLResponseInfo() { return NULL; }
 
- private:
   PluginModule* module_;  // Non-owning pointer to our module.
 
   DISALLOW_COPY_AND_ASSIGN(Resource);
 };
 
+// Cast() specializations.
+#define DEFINE_RESOURCE_CAST(Type)                   \
+  template <> inline Type* Resource::Cast<Type>() {  \
+      return As##Type();                             \
+  }
+
+DEFINE_RESOURCE_CAST(Buffer)
+DEFINE_RESOURCE_CAST(DeviceContext2D)
+DEFINE_RESOURCE_CAST(DirectoryReader)
+DEFINE_RESOURCE_CAST(FileChooser)
+DEFINE_RESOURCE_CAST(FileIO)
+DEFINE_RESOURCE_CAST(FileRef)
+DEFINE_RESOURCE_CAST(ImageData)
+DEFINE_RESOURCE_CAST(URLLoader)
+DEFINE_RESOURCE_CAST(URLRequestInfo)
+DEFINE_RESOURCE_CAST(URLResponseInfo)
+
+#undef DEFINE_RESOURCE_CAST
 }  // namespace pepper

[darin (slow to review), 2010/06/28 19:57:07]

nit: add a new line above the close of the namespace

 
 #endif  // WEBKIT_GLUE_PLUGINS_PEPPER_RESOURCE_H_