Cloning a bunch of stuff from the native_client repository at r6528

ppapi/native_client/src/shared/ppapi_proxy/plugin_resource.h

Index: ppapi/native_client/src/shared/ppapi_proxy/plugin_resource.h
===================================================================
--- ppapi/native_client/src/shared/ppapi_proxy/plugin_resource.h	(revision 0)
+++ ppapi/native_client/src/shared/ppapi_proxy/plugin_resource.h	(revision 0)
@@ -0,0 +1,149 @@
+// Copyright (c) 2011 The Native Client 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 NATIVE_CLIENT_SRC_SHARED_PPAPI_PROXY_PLUGIN_RESOURCE_H_
+#define NATIVE_CLIENT_SRC_SHARED_PPAPI_PROXY_PLUGIN_RESOURCE_H_
+
+#include "native_client/src/include/nacl_base.h"
+#include "native_client/src/include/ref_counted.h"
+#include "native_client/src/shared/ppapi_proxy/plugin_resource_tracker.h"
+#include "ppapi/c/pp_resource.h"
+
+namespace ppapi_proxy {
+
+// If you inherit from resource, make sure you add the class name here.
+#define FOR_ALL_RESOURCES(F) \
+  F(PluginAudio) \
+  F(PluginAudioConfig) \
+  F(PluginBuffer) \
+  F(PluginFont) \
+  F(PluginGraphics2D) \
+  F(PluginGraphics3D) \
+  F(PluginImageData) \
+  F(PluginInputEvent)
+
+// Forward declaration of PluginResource classes.
+#define DECLARE_RESOURCE_CLASS(RESOURCE) class RESOURCE;
+FOR_ALL_RESOURCES(DECLARE_RESOURCE_CLASS)
+#undef DECLARE_RESOURCE_CLASS
+
+class PluginResource : public nacl::RefCounted<PluginResource> {
+ public:
+  PluginResource();
+  virtual ~PluginResource();
+
+  // Returns NULL if the resource is invalid or is a different type.
+  template<typename T>
+  static scoped_refptr<T> GetAs(PP_Resource res) {
+    // See if we have the resource cached.
+    scoped_refptr<PluginResource> resource =
+        PluginResourceTracker::Get()->GetExistingResource(res);
+
+    return resource ? resource->Cast<T>() : NULL;
+  }
+
+  // Adopt the given PP_Resource as type T. Use this function for resources that
+  // the browser provides to the plugin with an incremented ref count (i.e.,
+  // calls AddRefResource); it initializes the browser refcount to 1 or
+  // increments it if the resource already exists.
+  // Returns NULL if the resource is invalid or is a different type.
+  template<typename T>
+  static scoped_refptr<T> AdoptAs(PP_Resource res);
+
+  // Adopt the given PP_Resource as type T. Use this function for resources
+  // when the browser drops the refcount immediately. These resources are
+  // typically meant to be cached on the plugin side, with little or no
+  // interaction back to the browser. For an example, see PluginInputEvent.
+  // This is like AdoptAs above, except it initializes the browser_refcount to
+  // 0 for resources that are new to the plugin, and does not increment the
+  // browser_refcount for resources that exist.
+  // Returns NULL if the resource is invalid or is a different type.
+  template<typename T>
+  static scoped_refptr<T> AdoptAsWithNoBrowserCount(PP_Resource res);
+
+  // 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; }
+
+ protected:
+  virtual bool InitFromBrowserResource(PP_Resource resource) = 0;
+
+ 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()
+  // function.
+  #define DEFINE_TYPE_GETTER(RESOURCE)  \
+      virtual RESOURCE* As##RESOURCE() { return NULL; }
+  FOR_ALL_RESOURCES(DEFINE_TYPE_GETTER)
+  #undef DEFINE_TYPE_GETTER
+
+  // Call this macro in the derived class declaration to actually implement the
+  // type getter.
+  #define IMPLEMENT_RESOURCE(RESOURCE)  \
+      virtual RESOURCE* As##RESOURCE() { return this; }
+
+  DISALLOW_COPY_AND_ASSIGN(PluginResource);
+};
+
+// Cast() specializations.
+#define DEFINE_RESOURCE_CAST(Type)                         \
+  template <> inline Type* PluginResource::Cast<Type>() {  \
+      return As##Type();                                   \
+  }
+
+FOR_ALL_RESOURCES(DEFINE_RESOURCE_CAST)
+#undef DEFINE_RESOURCE_CAST
+
+#undef FOR_ALL_RESOURCES
+
+template<typename T> scoped_refptr<T>
+PluginResourceTracker::AdoptBrowserResource(PP_Resource res,
+                                            size_t browser_refcount) {
+  ResourceMap::iterator result = live_resources_.find(res);
+  // Do we have it already?
+  if (result == live_resources_.end()) {
+    // No - try to create a new one.
+    scoped_refptr<T> new_resource = new T();
+    if (new_resource->InitFromBrowserResource(res)) {
+      AddResource(new_resource, res, browser_refcount);
+      return new_resource;
+    } else {
+      return scoped_refptr<T>();
+    }
+  } else {
+    // Consume more browser refcounts (unless browser_refcount is 0).
+    result->second.browser_refcount += browser_refcount;
+    return result->second.resource->Cast<T>();
+  }
+}
+
+template<typename T>
+scoped_refptr<T> PluginResource::AdoptAs(PP_Resource res) {
+  // Short-circuit if null resource.
+  if (!res)
+    return NULL;
+
+  // Adopt the resource with 1 browser-side refcount.
+  const size_t browser_refcount = 1;
+  return PluginResourceTracker::Get()->AdoptBrowserResource<T>(
+      res, browser_refcount);
+}
+
+template<typename T>
+scoped_refptr<T> PluginResource::AdoptAsWithNoBrowserCount(PP_Resource res) {
+  // Short-circuit if null resource.
+  if (!res)
+    return NULL;
+
+  // Adopt the resource with 0 browser-side refcount.
+  const size_t browser_refcount = 0;
+  return PluginResourceTracker::Get()->AdoptBrowserResource<T>(
+      res, browser_refcount);
+}
+
+}  // namespace ppapi_proxy
+
+#endif  // NATIVE_CLIENT_SRC_SHARED_PPAPI_PROXY_PLUGIN_RESOURCE_H_
+