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

chrome/browser/extensions/declarative_user_script_master.cc

+// 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.
+
+#include "chrome/browser/extensions/declarative_user_script_master.h"
+
+#include "chrome/browser/chrome_notification_types.h"
+#include "chrome/browser/extensions/extension_util.h"
+#include "chrome/browser/profiles/profile.h"
+#include "chrome/common/extensions/api/i18n/default_locale_handler.h"
+#include "content/public/browser/notification_service.h"
+#include "content/public/browser/render_process_host.h"
+#include "extensions/browser/content_verifier.h"
+#include "extensions/browser/extension_registry.h"
+#include "extensions/browser/extension_system.h"
+
+namespace extensions {
+
+DeclarativeUserScriptMaster::DeclarativeUserScriptMaster(
+    Profile* profile,
+    const ExtensionId& extension_id)
+    : UserScriptMaster(profile, extension_id),
+      user_scripts_(new UserScriptList()) {
+  owner_extension_as_set_.insert(extension_id);
+  const Extension* extension =
+      ExtensionRegistry::Get(this->profile())
+          ->GetExtensionById(owner_extension_id(), ExtensionRegistry::ENABLED);
+  DCHECK(extension);
+  extensions_info_[owner_extension_id()] =
+      ExtensionSet::ExtensionPathAndDefaultLocale(
+          extension->path(), LocaleInfo::GetDefaultLocale(extension));
+}
+
+DeclarativeUserScriptMaster::~DeclarativeUserScriptMaster() {
+}
+
+void DeclarativeUserScriptMaster::AddScript(const UserScript& script) {
+  scripts_to_add_.insert(script);
+  AttemptLoad();
+}
+
+void DeclarativeUserScriptMaster::RemoveScript(const UserScript& script) {
+  if (scripts_to_add_.count(script) != 0)
+    scripts_to_add_.erase(script);
+  else
+    scripts_to_remove_.insert(script);
+  AttemptLoad();

[Devlin, 2014/07/31 20:32:23]

Seems to me there's no reason to attempt the load if it was just removed from
the scripts_to_add_ list, right?  Similarly, no reason to reload if the script
is not present in user_scripts_?  And if clear_scripts_ is set to true, we want
to not add this to scripts_to_remove_?

+}
+
+void DeclarativeUserScriptMaster::ClearScripts() {
+  clear_scripts_ = true;
+  scripts_to_add_.clear();
+  scripts_to_remove_.clear();
+  AttemptLoad();
+}
+
+void DeclarativeUserScriptMaster::StartLoad() {
+  if (clear_scripts_) {
+    user_scripts_->clear();
+  }
+  bool incognito_enabled =
+      util::IsIncognitoEnabled(owner_extension_id(), profile());
+  std::set<UserScript> new_user_scripts;
+  new_user_scripts.insert(user_scripts_->begin(), user_scripts_->end());

[Devlin, 2014/07/31 20:32:23]

If we wanted to be cool, we would do:
user_scripts_ = STLSetUnion(STLSetDifference(user_scripts_, scripts_to_remove_),
                            scripts_to_add_);

+  for (std::set<UserScript>::iterator it = scripts_to_remove_.begin();
+       it != scripts_to_remove_.end();
+       ++it) {
+    new_user_scripts.erase(*it);
+  }
+  for (std::set<UserScript>::const_iterator it = scripts_to_add_.begin();
+       it != scripts_to_add_.end();
+       ++it) {
+    UserScript script = *it;
+    script.set_incognito_enabled(incognito_enabled);
+    new_user_scripts.insert(script);
+  }
+  user_scripts_->assign(new_user_scripts.begin(), new_user_scripts.end());
+
+  LoadScripts(user_scripts_.Pass(), extensions_info_);
+
+  user_scripts_.reset(NULL);
+  scripts_to_add_.clear();
+  scripts_to_remove_.clear();
+  clear_scripts_ = false;
+}
+
+void DeclarativeUserScriptMaster::AcquireUserScripts(
+    scoped_ptr<UserScriptList> scripts) {
+  user_scripts_.reset(scripts.release());
+}
+
+ExtensionsInfo DeclarativeUserScriptMaster::GetExtensionsInfo() {
+  return extensions_info_;
+}
+
+std::set<ExtensionId> DeclarativeUserScriptMaster::GetAddedExtensions() {
+  // If loading from the file thread has been triggered, then reload scripts
+  // for the one extension that we manage.
+  return owner_extension_as_set_;
+}
+
+std::set<ExtensionId> DeclarativeUserScriptMaster::GetAllManagedExtensions() {
+  return owner_extension_as_set_;
+}
+
+std::set<ExtensionId> DeclarativeUserScriptMaster::GetChangedExtensions() {
+  // In any context where we need to know which extensions have changed, assume
+  // that the extension we manage may have changed.
+  return owner_extension_as_set_;
+}
+
+void DeclarativeUserScriptMaster::ResetChangedExtensions() {
+  // No extra bookkeeping for tracking changed extensions.
+}
+
+void DeclarativeUserScriptMaster::AttemptLoad() {
+  if (is_loading())
+    MaybeSignalPendingLoad();
+  else
+    StartLoad();
+}
+
+void DeclarativeUserScriptMaster::MaybeSignalPendingLoad() {
+  if (clear_scripts_ || scripts_to_add_.size() > 0 ||
+      scripts_to_remove_.size() > 0)
+    SignalPendingLoad();
+}
+
+}  // namespace extensions