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

ppapi/proxy/plugin_resource_tracker.cc

 // 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.
 
 #include "ppapi/proxy/plugin_resource_tracker.h"
 
 #include "base/logging.h"
 #include "base/singleton.h"
 #include "ppapi/proxy/plugin_dispatcher.h"
 #include "ppapi/proxy/ppapi_messages.h"
 #include "ppapi/proxy/plugin_resource.h"
 #include "ppapi/proxy/serialized_var.h"
 
 namespace pp {
 namespace proxy {
 
+namespace {
+
+// When non-NULL, this object overrides the ResourceTrackerSingleton.
+PluginResourceTracker* g_resource_tracker_override = NULL;
+
+}  // namespace
+
 PluginResourceTracker::ResourceInfo::ResourceInfo() : ref_count(0) {
 }
 
 PluginResourceTracker::ResourceInfo::ResourceInfo(int rc,
                                                   linked_ptr<PluginResource> r)
     : ref_count(rc),
       resource(r) {
 }
 
 PluginResourceTracker::ResourceInfo::ResourceInfo(const ResourceInfo& other)
     : ref_count(other.ref_count),
       resource(other.resource) {
 }
 
 PluginResourceTracker::ResourceInfo::~ResourceInfo() {
 }
 
 PluginResourceTracker::ResourceInfo&
 PluginResourceTracker::ResourceInfo::operator=(
     const ResourceInfo& other) {
   ref_count = other.ref_count;
   resource = other.resource;
   return *this;
 }
 
-PluginResourceTracker::PluginResourceTracker() {
+// Start counting resources at a high number to avoid collisions with vars (to
+// help debugging).
+PluginResourceTracker::PluginResourceTracker()
+    : last_resource_id_(0x00100000) {
 }
 
 PluginResourceTracker::~PluginResourceTracker() {
 }
 
 // static
+void PluginResourceTracker::SetInstanceForTest(PluginResourceTracker* tracker) {
+  g_resource_tracker_override = tracker;
+}
+
+// static
 PluginResourceTracker* PluginResourceTracker::GetInstance() {
+  if (g_resource_tracker_override)
+    return g_resource_tracker_override;
   return Singleton<PluginResourceTracker>::get();
 }
 
 PluginResource* PluginResourceTracker::GetResourceObject(
     PP_Resource pp_resource) {
   ResourceMap::iterator found = resource_map_.find(pp_resource);
   if (found == resource_map_.end())
     return NULL;
   return found->second.resource.get();
 }
 
-void PluginResourceTracker::AddResource(PP_Resource pp_resource,
-                                        linked_ptr<PluginResource> object) {
-  DCHECK(resource_map_.find(pp_resource) == resource_map_.end());
-  resource_map_[pp_resource] = ResourceInfo(1, object);
+PP_Resource PluginResourceTracker::AddResource(
+    linked_ptr<PluginResource> object) {
+  if (object->host_resource().is_null()) {
+    // Prevent adding null resources or GetResourceObject(0) will return a
+    // valid pointer!
+    NOTREACHED();
+    return 0;
+  }
+
+  PP_Resource plugin_resource = ++last_resource_id_;
+  DCHECK(resource_map_.find(plugin_resource) == resource_map_.end());
+  resource_map_[plugin_resource] = ResourceInfo(1, object);
+  host_resource_map_[object->host_resource()] = plugin_resource;
+  return plugin_resource;
 }
 
 void PluginResourceTracker::AddRefResource(PP_Resource resource) {
-  resource_map_[resource].ref_count++;
+  ResourceMap::iterator found = resource_map_.find(resource);
+  if (found == resource_map_.end()) {
+    NOTREACHED();
+    return;
+  }
+  found->second.ref_count++;
 }
 
 void PluginResourceTracker::ReleaseResource(PP_Resource resource) {
   ReleasePluginResourceRef(resource, true);
 }
 
-bool PluginResourceTracker::PreparePreviouslyTrackedResource(
-    PP_Resource resource) {
-  ResourceMap::iterator found = resource_map_.find(resource);
-  if (found == resource_map_.end())
-    return false;  // We've not seen this resource before.
-
-  // We have already seen this resource and the caller wants the plugin to
-  // have one more ref to the object (this function is called when retuning
-  // a resource).
-  //
-  // This is like the PluginVarTracker::ReceiveObjectPassRef. We do an AddRef
-  // in the plugin for the additional ref, and then a Release in the renderer
-  // because the code in the renderer addrefed on behalf of the caller.
-  found->second.ref_count++;
-
-  SendReleaseResourceToHost(resource, found->second.resource.get());
-  return true;
+PP_Resource PluginResourceTracker::PluginResourceForHostResource(
+    const HostResource& resource) const {
+  HostResourceMap::const_iterator found = host_resource_map_.find(resource);
+  if (found == host_resource_map_.end())
+    return 0;
+  return found->second;
 }
 
 void PluginResourceTracker::ReleasePluginResourceRef(
     const PP_Resource& resource,
     bool notify_browser_on_release) {
   ResourceMap::iterator found = resource_map_.find(resource);
   if (found == resource_map_.end())
     return;
   found->second.ref_count--;
   if (found->second.ref_count == 0) {
+    PluginResource* plugin_resource = found->second.resource.get();
     if (notify_browser_on_release)
-      SendReleaseResourceToHost(resource, found->second.resource.get());
+      SendReleaseResourceToHost(resource, plugin_resource);
+    host_resource_map_.erase(plugin_resource->host_resource());
     resource_map_.erase(found);
   }
 }
 
 void PluginResourceTracker::SendReleaseResourceToHost(
     PP_Resource resource_id,
     PluginResource* resource) {
   PluginDispatcher* dispatcher =
       PluginDispatcher::GetForInstance(resource->instance());
   if (dispatcher) {
     dispatcher->Send(new PpapiHostMsg_PPBCore_ReleaseResource(
-        INTERFACE_ID_PPB_CORE, resource_id));
+        INTERFACE_ID_PPB_CORE, resource->host_resource()));
   } else {
     NOTREACHED();
   }
 }
 
 }  // namespace proxy
 }  // namespace pp