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

chrome/browser/extensions/user_script_loader.h

+// Copyright 2014 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_LOADER_H_
+#define CHROME_BROWSER_EXTENSIONS_USER_SCRIPT_LOADER_H_
+
+#include <map>
+#include <set>
+
+#include "base/compiler_specific.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/memory/weak_ptr.h"
+#include "content/public/browser/notification_observer.h"
+#include "content/public/browser/notification_registrar.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<ExtensionId, ExtensionSet::ExtensionPathAndDefaultLocale>
+    ExtensionsInfo;
+
+// Manages one "logical unit" of user scripts in shared memory by constructing a
+// new shared memory region when the set of scripts changes. Also notifies
+// renderers of new shared memory region when new renderers appear, or when
+// script reloading completes. Script loading lives on the UI thread. Instances
+// of this class are embedded within classes with names ending in
+// UserScriptMaster. These "master" classes implement the strategy for which
+// scripts to load/unload on this logical unit of scripts.
+class UserScriptLoader : public content::NotificationObserver {
+ 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(std::set<UserScript>* user_scripts);
+
+  UserScriptLoader(Profile* profile,
+                   const ExtensionId& owner_extension_id,
+                   bool listen_for_extension_system_loaded);
+  virtual ~UserScriptLoader();
+
+  // Gets the segment of shared memory for the scripts.
+  base::SharedMemory* GetSharedMemory() const { return shared_memory_.get(); }

[Devlin, 2014/08/05 21:47:27]

Do we need this?

[Mark Dittmer, 2014/08/06 15:32:25]

Not really. Removed.

+
+  // Return true if we have any scripts ready.
+  bool scripts_ready() const { return shared_memory_.get() != NULL; }

[Devlin, 2014/08/05 21:47:27]

nit: prefer accessors right above private:

[Mark Dittmer, 2014/08/06 15:32:25]

Done.

+
+  // Add |scripts| to the set of scripts managed by this loader.
+  void AddScripts(const std::set<UserScript>& scripts);
+
+  // Remove |scripts| from the set of scripts managed by this loader.
+  void RemoveScripts(const std::set<UserScript>& scripts);
+
+  // Clear the set of scripts managed by this loader; i.e., make this set be

[Devlin, 2014/08/05 21:47:27]

lose the i.e..  I think "clear the set" is suitably clear.

[Mark Dittmer, 2014/08/06 15:32:25]

Done.

+  // the empty set.
+  void ClearScripts();
+
+  // Initiates procedure to start loading scripts on the file thread.
+  void StartLoad();
+
+ private:
+  // Initiates script load when we have been waiting for the extension system
+  // to be ready.
+  void OnExtensionSystemReady();
+
+  // content::NotificationObserver implementation.
+  virtual void Observe(int type,
+                       const content::NotificationSource& source,
+                       const content::NotificationDetails& details) OVERRIDE;
+
+  // Attempt to initiate a load.
+  void AttemptLoad();
+
+  // Called once we have finished loading the scripts on the file thread.
+  void OnScriptsLoaded(scoped_ptr<std::set<UserScript> > user_scripts,
+                       scoped_ptr<base::SharedMemory> shared_memory);

[Devlin, 2014/08/05 21:47:27]

newline

[Mark Dittmer, 2014/08/06 15:32:25]

Done.

+  // 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<ExtensionId>& changed_extensions);
+
+  // Update |changed_extensions_| to be the extensions referred to in
+  // |added_scripts_| and |removed_scripts_|.
+  void ComputeChangedExtensions();
+
+  // Update |extensions_info_| to contain info for each element of
+  // |changed_extensions_|.
+  void UpdateExtensionsInfo();
+
+  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_;
+
+  // Set of scripts from currently-installed extensions we should load.
+  scoped_ptr<std::set<UserScript> > user_scripts_;
+
+  // Maps extension info needed for localization to an extension ID.
+  ExtensionsInfo extensions_info_;
+
+  // The mutually-exclusive sets of scripts that were added or removed since the
+  // last script load.
+  std::set<UserScript> added_scripts_;
+  std::set<UserScript> removed_scripts_;
+
+  // Indicates whether the the collection of scripts should be cleared before
+  // additions and removals on the next script load.
+  bool clear_scripts_;
+
+  // The IDs of the extensions which changed in the last update sent to the
+  // renderer.
+  std::set<ExtensionId> changed_extensions_;
+
+  // If the extensions service has finished loading its initial set of
+  // extensions.
+  bool extension_system_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_;
+
+  // Whether or not we are currently loading.
+  bool is_loading_;
+
+  // The profile for which the scripts managed here are installed.
+  Profile* profile_;
+
+  // ID of the extension that owns these scripts, if any. This is only set to a
+  // non-empty value for declarative user script shared memory regions.
+  ExtensionId owner_extension_id_;
+
+  base::WeakPtrFactory<UserScriptLoader> weak_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(UserScriptLoader);
+};
+
+}  // namespace extensions
+
+#endif  // CHROME_BROWSER_EXTENSIONS_USER_SCRIPT_LOADER_H_