Refactor extension bindings to share code, avoid exposing hidden variables

chrome/renderer/extensions/bindings_utils.h

 // Copyright (c) 2009 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 CHROME_RENDERER_EXTENSIONS_BINDINGS_UTILS_H_
 #define CHROME_RENDERER_EXTENSIONS_BINDINGS_UTILS_H_
 
 #include "app/resource_bundle.h"
+#include "base/linked_ptr.h"
 #include "base/singleton.h"
 #include "base/string_piece.h"
 #include "v8/include/v8.h"
 
+#include <list>
 #include <string>
 
 class RenderView;
+class WebFrame;
+
+namespace bindings_utils {
+
+// This is a base class for chrome extension bindings.  Common features that
+// are shared by different modules go here.
+class ExtensionBase : public v8::Extension {
+ public:
+  ExtensionBase(const char* name,
+                const char* source,
+                int dep_count,
+                const char** deps)
+      : v8::Extension(name, source, dep_count, deps) {}
+
+  // Derived classes should call this at the end of their implementation in
+  // order to expose common native functions, like GetChromeHidden, to the
+  // v8 extension.
+  virtual v8::Handle<v8::FunctionTemplate>
+      GetNativeFunction(v8::Handle<v8::String> name);
+
+ protected:
+  // Returns a hidden variable for use by the bindings that is unreachable
+  // by the page.
+  static v8::Handle<v8::Value> GetChromeHidden(const v8::Arguments& args);
+
+  // Starts an API request to the browser, with an optional callback.  The
+  // callback will be dispatched to EventBindings::HandleResponse.
+  static v8::Handle<v8::Value> StartRequest(const v8::Arguments& args);
+};
 
 template<int kResourceId>
 struct StringResourceTemplate {
   StringResourceTemplate()
       : resource(ResourceBundle::GetSharedInstance().GetRawDataResource(
             kResourceId).as_string()) {
   }
   std::string resource;
 };
 
 template<int kResourceId>
 const char* GetStringResource() {
   return
       Singleton< StringResourceTemplate<kResourceId> >::get()->resource.c_str();
 }
 
+// Contains information about a single Javascript context.
+struct ContextInfo {
+  v8::Persistent<v8::Context> context;
+  std::string extension_id;  // empty if the context is not an extension
+
+  ContextInfo(v8::Persistent<v8::Context> context,
+              const std::string& extension_id)
+      : context(context), extension_id(extension_id) {}
+};
+typedef std::list< linked_ptr<ContextInfo> > ContextList;
+
+// Returns a mutable reference to the ContextList.
+ContextList& GetContexts();
+
+// Returns a (copied) list of contexts that have the given extension_id.
+ContextList GetContextsForExtension(const std::string& extension_id);
+
+// Returns the ContextInfo item that has the given context.
+ContextList::iterator FindContext(v8::Handle<v8::Context> context);
+
+// Contains info relevant to a pending API request.
+struct PendingRequest {
+ public :
+  PendingRequest(v8::Persistent<v8::Context> context, const std::string& name)
+      : context(context), name(name) {
+  }
+  v8::Persistent<v8::Context> context;
+  std::string name;
+};
+typedef std::map<int, linked_ptr<PendingRequest> > PendingRequestMap;
+
+// Returns a mutable reference to the PendingRequestMap.
+PendingRequestMap& GetPendingRequestMap();
+
 // Returns the current RenderView, based on which V8 context is current.  It is
 // an error to call this when not in a V8 context.
 RenderView* GetRenderViewForCurrentContext();
 
 // Call the named javascript function with the given arguments in a context.
-// The function name should be reachable from the global object, and can be a
-// sub-property like "chrome.handleResponse_".
+// The function name should be reachable from the chromeHidden object, and can
+// be a sub-property like "Port.dispatchOnMessage".
 void CallFunctionInContext(v8::Handle<v8::Context> context,
                            const std::string& function_name, int argc,
                            v8::Handle<v8::Value>* argv);
 
+}  // namespace bindings_utils
+
 #endif  // CHROME_RENDERER_EXTENSIONS_BINDINGS_UTILS_H_