Declarative content scripts: Browser-side: per-extension shared memory regions (lazily loaded)

chrome/browser/extensions/user_script_master.h

 // Copyright (c) 2012 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_BROWSER_EXTENSIONS_USER_SCRIPT_MASTER_H_
 #define CHROME_BROWSER_EXTENSIONS_USER_SCRIPT_MASTER_H_
 
 #include <map>
 #include <string>
 
 #include "base/compiler_specific.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
-#include "base/scoped_observer.h"
 #include "content/public/browser/browser_thread.h"
-#include "content/public/browser/notification_observer.h"
-#include "content/public/browser/notification_registrar.h"
-#include "extensions/browser/extension_registry_observer.h"
 #include "extensions/common/extension_messages.h"
 #include "extensions/common/extension_set.h"
 #include "extensions/common/user_script.h"
 
 namespace base {
 class SharedMemory;
 }
 
 namespace content {
 class RenderProcessHost;
 }
 
 class Profile;
 
 namespace extensions {
 
 class ContentVerifier;
 class ExtensionRegistry;
 
 typedef std::map<std::string, ExtensionSet::ExtensionPathAndDefaultLocale>
     ExtensionsInfo;
 
 // Manages a segment of shared memory that contains the user scripts the user
 // has installed.  Lives on the UI thread.
-class UserScriptMaster : public content::NotificationObserver,
-                         public ExtensionRegistryObserver {
+class UserScriptMaster {
  public:
   // Parses the includes out of |script| and returns them in |includes|.
   static bool ParseMetadataHeader(const base::StringPiece& script_text,
                                   UserScript* script);
 
   // A wrapper around the method to load user scripts, which is normally run on
   // the file thread. Exposed only for tests.
   static void LoadScriptsForTest(UserScriptList* user_scripts);
 
   explicit UserScriptMaster(Profile* profile);
   virtual ~UserScriptMaster();
 
   // Kicks off a process on the file thread to reload scripts from disk
   // into a new chunk of shared memory and notify renderers.
-  virtual void StartLoad();
+  virtual void StartLoad() = 0;
 
   // Gets the segment of shared memory for the scripts.
   base::SharedMemory* GetSharedMemory() const {
     return shared_memory_.get();
   }
 
   // Return true if we have any scripts ready.
   bool ScriptsReady() const { return shared_memory_.get() != NULL; }
 
- private:
-  // content::NotificationObserver implementation.
-  virtual void Observe(int type,
-                       const content::NotificationSource& source,
-                       const content::NotificationDetails& details) OVERRIDE;
-
-  // ExtensionRegistryObserver implementation.
-  virtual void OnExtensionLoaded(content::BrowserContext* browser_context,
-                                 const Extension* extension) OVERRIDE;
-  virtual void OnExtensionUnloaded(
-      content::BrowserContext* browser_context,
-      const Extension* extension,
-      UnloadedExtensionInfo::Reason reason) OVERRIDE;
-
   // Called once we have finished loading the scripts on the file thread.
   void OnScriptsLoaded(scoped_ptr<UserScriptList> user_scripts,
                        scoped_ptr<base::SharedMemory> shared_memory);
 
+ protected:
+  typedef base::Callback<
+      void(scoped_ptr<UserScriptList>, scoped_ptr<base::SharedMemory>)>
+      LoadScriptsCallback;
+
+  static void LoadScriptsOnFileThread(
+      scoped_ptr<UserScriptList> user_scripts,
+      const ExtensionsInfo& extensions_info,
+      const std::set<std::string>& new_extensions,
+      scoped_refptr<ContentVerifier> verifier,
+      LoadScriptsCallback callback);
+
+  bool is_loading() const {
+    // Ownership of |user_scripts_| is passed to the file thread when loading.
+    return user_scripts_.get() == NULL;
+  }
+
   // Sends the renderer process a new set of user scripts. If
   // |changed_extensions| is not empty, this signals that only the scripts from
   // those extensions should be updated. Otherwise, all extensions will be
   // updated.
   void SendUpdate(content::RenderProcessHost* process,
                   base::SharedMemory* shared_memory,
                   const std::set<std::string>& changed_extensions);
 
-  bool is_loading() const {
-    // Ownership of |user_scripts_| is passed to the file thread when loading.
-    return user_scripts_.get() == NULL;
-  }
-
-  // Manages our notification registrations.
-  content::NotificationRegistrar registrar_;
-
-  // Contains the scripts that were found the last time scripts were updated.
-  scoped_ptr<base::SharedMemory> shared_memory_;
-
   // List of scripts from currently-installed extensions we should load.
   scoped_ptr<UserScriptList> user_scripts_;
 
   // Maps extension info needed for localization to an extension ID.
   ExtensionsInfo extensions_info_;
 
   // The IDs of the extensions which have changed since the last update sent to
   // the renderer.
   std::set<std::string> changed_extensions_;
 
   // The mutually-exclusive sets of extensions that were added or removed since
   // the last script load.
   std::set<std::string> added_extensions_;
   std::set<std::string> removed_extensions_;
 
   // If the extensions service has finished loading its initial set of
   // extensions.
   bool extensions_service_ready_;
 
   // If list of user scripts is modified while we're loading it, we note
   // that we're currently mid-load and then start over again once the load
   // finishes.  This boolean tracks whether another load is pending.
   bool pending_load_;
 
+  // The profile for which the scripts managed here are installed.
+  Profile* profile_;
+
+  base::WeakPtrFactory<UserScriptMaster> weak_factory_;
+
+  // ID of extension that owns this region, if any. This is the empty string in
+  // the case of the memory region for statically declared content scripts,
+  // which is shared between extensions.
+  ExtensionId owner_extension_id_;
+
+ private:
+  // Contains the scripts that were found the last time scripts were updated.
+  scoped_ptr<base::SharedMemory> shared_memory_;
+
   // Whether or not we are currently loading.
   bool is_loading_;
 
-  // The profile for which the scripts managed here are installed.
-  Profile* profile_;
-
-  // Listen to extension load, unloaded notifications.
-  ScopedObserver<ExtensionRegistry, ExtensionRegistryObserver>
-      extension_registry_observer_;
-
-  base::WeakPtrFactory<UserScriptMaster> weak_factory_;
-
   DISALLOW_COPY_AND_ASSIGN(UserScriptMaster);
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_USER_SCRIPT_MASTER_H_