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

chrome/browser/extensions/shared_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/shared_user_script_master.h"
+
+#include "chrome/browser/extensions/extension_util.h"
+#include "chrome/browser/profiles/profile.h"

[Devlin, 2014/08/06 15:59:25]

Don't need this.

[Mark Dittmer, 2014/08/06 22:08:18]

Do too :-P  For profile_.

[Devlin, 2014/08/07 15:46:31]

We never really use profile_, so just knowing that "something" is a profile is
sufficient (via a forward declare).  But we actually *do* need it for
ExtensionRegistry::Get(), because it takes a BrowserContext, so we need to know
that a profile is a browser context, so we need profile.h.  D'oh.  My bad. :)

[Mark Dittmer, 2014/08/11 14:08:04]

Acknowledged.

+#include "chrome/common/extensions/manifest_handlers/content_scripts_handler.h"
+#include "extensions/browser/extension_registry.h"
+
+namespace extensions {
+
+SharedUserScriptMaster::SharedUserScriptMaster(Profile* profile)
+    : loader_(profile,
+              std::string() /* owner_extension_id */,
+              true /* listen_for_extension_system_loaded */),
+      profile_(profile),
+      extension_registry_observer_(this) {
+  extension_registry_observer_.Add(ExtensionRegistry::Get(profile_));
+}
+
+SharedUserScriptMaster::~SharedUserScriptMaster() {
+}
+
+void SharedUserScriptMaster::OnExtensionLoaded(
+    content::BrowserContext* browser_context,
+    const Extension* extension) {
+  loader_.AddScripts(GetScriptsMetadata(extension));
+}
+
+void SharedUserScriptMaster::OnExtensionUnloaded(
+    content::BrowserContext* browser_context,
+    const Extension* extension,
+    UnloadedExtensionInfo::Reason reason) {
+  loader_.RemoveScripts(GetScriptsMetadata(extension));
+  loader_.ClearExtensionInfo(extension->id());
+  scripts_metadata_.erase(extension->id());
+}
+
+const std::set<UserScript>& SharedUserScriptMaster::GetScriptsMetadata(
+    const Extension* extension) {
+  const ExtensionId& id = extension->id();
+  std::map<ExtensionId, std::set<UserScript> >::const_iterator iter =
+      scripts_metadata_.find(id);
+  if (iter != scripts_metadata_.end())
+    return iter->second;
+
+  scripts_metadata_[id] = std::set<UserScript>();

[Devlin, 2014/08/06 15:59:25]

I'm somewhat dubious of the benefit of storing all these scripts in memory.  We
only need them in loaded and unloaded, so it might be better to just fetch them
each time (and for unloaded, we don't need to go through the trouble of setting
the incognito bit).  But I'll leave it up to you.

[Mark Dittmer, 2014/08/06 22:08:18]

Got rid of scripts_metadata_, but I am leaving the incognito part alone. The
lookup shouldn't be expensive, and branching on a variable, set_incognito, makes
this simple function needlessly complex -- either we check set_incognito on
every iteration, or we duplicate nearly the whole function with and without
set_incognito_enabled().

[Devlin, 2014/08/07 15:46:31]

Works for me.

[Mark Dittmer, 2014/08/11 14:08:04]

Acknowledged.

+  bool incognito_enabled = util::IsIncognitoEnabled(id, profile_);
+  const UserScriptList& fetched_scripts =
+      ContentScriptsInfo::GetContentScripts(extension);
+  std::set<UserScript>& stored_scripts = scripts_metadata_[id];
+  for (UserScriptList::const_iterator it = fetched_scripts.begin();
+       it != fetched_scripts.end();
+       ++it) {
+    UserScript script = *it;
+    script.set_incognito_enabled(incognito_enabled);
+    stored_scripts.insert(script);
+  }
+
+  return stored_scripts;
+}
+
+}  // namespace extensions