A proposal for an initial postMessage interface. This will allow JavaScript ...

webkit/plugins/ppapi/ppapi_plugin_instance.cc

Index: webkit/plugins/ppapi/ppapi_plugin_instance.cc
===================================================================
--- webkit/plugins/ppapi/ppapi_plugin_instance.cc	(revision 77426)
+++ webkit/plugins/ppapi/ppapi_plugin_instance.cc	(working copy)
@@ -42,6 +42,7 @@
 #include "webkit/plugins/ppapi/common.h"
 #include "webkit/plugins/ppapi/event_conversion.h"
 #include "webkit/plugins/ppapi/fullscreen_container.h"
+#include "webkit/plugins/ppapi/message_channel.h"
 #include "webkit/plugins/ppapi/plugin_delegate.h"
 #include "webkit/plugins/ppapi/plugin_module.h"
 #include "webkit/plugins/ppapi/plugin_object.h"
@@ -99,7 +100,8 @@
 namespace {
 
 #define COMPILE_ASSERT_MATCHING_ENUM(webkit_name, np_name) \
-    COMPILE_ASSERT(int(WebCursorInfo::webkit_name) == int(np_name), \
+    COMPILE_ASSERT(static_cast<int>(WebCursorInfo::webkit_name) \
+                       == static_cast<int>(np_name), \
                    mismatching_enums)
 
 COMPILE_ASSERT_MATCHING_ENUM(TypePointer, PP_CURSORTYPE_POINTER);
@@ -201,12 +203,20 @@
   return instance->ExecuteScript(script, exception);
 }
 
+void PostMessage(PP_Instance instance_id, PP_Var message) {
+  PluginInstance* instance = ResourceTracker::Get()->GetInstance(instance_id);
+  if (!instance)
+    return;
+  instance->PostMessage(message);
+}
+
 const PPB_Instance ppb_instance = {
   &GetWindowObject,
   &GetOwnerElementObject,
   &BindGraphics,
   &IsFullFrame,
   &ExecuteScript,
+  &PostMessage
 };
 
 void NumberOfFindResultsChanged(PP_Instance instance_id,
@@ -314,7 +324,8 @@
 
 PluginInstance::PluginInstance(PluginDelegate* delegate,
                                PluginModule* module,
-                               const PPP_Instance* instance_interface)
+                               const PPP_Instance* instance_interface,
+                               InterfaceOwner ppp_instance_owner)
     : delegate_(delegate),
       module_(module),
       instance_interface_(instance_interface),
@@ -335,13 +346,16 @@
       plugin_graphics_3d_interface_(NULL),
       always_on_top_(false),
       fullscreen_container_(NULL),
-      fullscreen_(false) {
+      fullscreen_(false),
+      message_channel_(NULL),
+      ppp_instance_owner_(ppp_instance_owner) {
   pp_instance_ = ResourceTracker::Get()->AddInstance(this);
 
   memset(&current_print_settings_, 0, sizeof(current_print_settings_));
   DCHECK(delegate);
   module_->InstanceCreated(this);
   delegate_->InstanceCreated(this);
+  message_channel_.reset(new MessageChannel(this));
 }
 
 PluginInstance::~PluginInstance() {
@@ -363,11 +377,25 @@
 #if defined(OS_LINUX)
   ranges_.clear();
 #endif  // defined(OS_LINUX)
+
+  if (BROWSER_OWNS_INTERFACE == ppp_instance_owner_)
+    delete const_cast<PPP_Instance*>(instance_interface_);
 }
 
 // static
-const PPB_Instance* PluginInstance::GetInterface() {
-  return &ppb_instance;
+const void* PluginInstance::GetInterface(const std::string& interface) {
+  // At the time of writing, we support both 0.4 and 0.5.  But for future-
+  // proofing, we also compare to PPB_INSTANCE_INTERFACE so that we can work
+  // with later versions, assuming other parts work.  If PPB_Instance changes
+  // in a fashion that breaks the struct layout (e.g. modifying or deleting
+  // functions), this code must either get more complicated (to return a
+  // different, backwards-compatible struct) or just get rid of support for
+  // 0.4 and 0.5.
+  if ((interface == PPB_INSTANCE_INTERFACE_0_4)
+      || (interface == PPB_INSTANCE_INTERFACE_0_5)
+      || (interface == PPB_INSTANCE_INTERFACE))
+    return &ppb_instance;
+  return NULL;
 }
 
 // static
@@ -590,6 +618,10 @@
   return ret;
 }
 
+void PluginInstance::PostMessage(PP_Var message) {
+  message_channel_->PostMessageToJavaScript(message);
+}
+
 void PluginInstance::Delete() {
   // Keep a reference on the stack. See NOTE above.
   scoped_refptr<PluginInstance> ref(this);
@@ -649,6 +681,13 @@
   return rv;
 }
 
+void PluginInstance::HandleMessage(PP_Var message) {
+  if ((instance_interface_ != NULL) &&
+      (instance_interface_->HandleMessage != NULL)) {
+    instance_interface_->HandleMessage(pp_instance(), message);
+  }
+}
+
 PP_Var PluginInstance::GetInstanceObject() {
   return instance_interface_->GetInstanceObject(pp_instance());
 }