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

chrome/browser/extensions/shared_user_script_master.cc

+// Copyright (c) 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 "base/bind.h"
+#include "base/memory/shared_memory.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 "chrome/common/extensions/manifest_handlers/content_scripts_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_system.h"
+
+namespace extensions {
+
+SharedUserScriptMaster::SharedUserScriptMaster(Profile* profile)
+    : UserScriptMaster(profile), extension_registry_observer_(this) {
+  extension_registry_observer_.Add(ExtensionRegistry::Get(profile_));
+  registrar_.Add(this,
+                 chrome::NOTIFICATION_EXTENSIONS_READY,
+                 content::Source<Profile>(profile_));
+  registrar_.Add(this,
+                 content::NOTIFICATION_RENDERER_PROCESS_CREATED,
+                 content::NotificationService::AllBrowserContextsAndSources());
+}
+
+SharedUserScriptMaster::~SharedUserScriptMaster() {
+}
+
+void SharedUserScriptMaster::OnExtensionLoaded(
+    content::BrowserContext* browser_context,
+    const Extension* extension) {
+  added_extensions_.insert(extension->id());
+  removed_extensions_.erase(extension->id());
+  extensions_info_[extension->id()] =
+      ExtensionSet::ExtensionPathAndDefaultLocale(
+          extension->path(), LocaleInfo::GetDefaultLocale(extension));
+  if (extensions_service_ready_) {
+    changed_extensions_.insert(extension->id());
+    if (is_loading())
+      pending_load_ = true;
+    else
+      StartLoad();
+  }
+}
+
+void SharedUserScriptMaster::OnExtensionUnloaded(
+    content::BrowserContext* browser_context,
+    const Extension* extension,
+    UnloadedExtensionInfo::Reason reason) {
+  removed_extensions_.insert(extension->id());
+  added_extensions_.erase(extension->id());
+  // Remove any content scripts.
+  extensions_info_.erase(extension->id());
+  changed_extensions_.insert(extension->id());
+  if (is_loading())
+    pending_load_ = true;
+  else
+    StartLoad();
+}
+
+void SharedUserScriptMaster::Observe(
+    int type,
+    const content::NotificationSource& source,
+    const content::NotificationDetails& details) {
+  bool should_start_load = false;
+  switch (type) {
+    case chrome::NOTIFICATION_EXTENSIONS_READY:
+      extensions_service_ready_ = true;
+      should_start_load = true;
+      break;
+    case content::NOTIFICATION_RENDERER_PROCESS_CREATED: {
+      content::RenderProcessHost* process =
+          content::Source<content::RenderProcessHost>(source).ptr();
+      Profile* profile =
+          Profile::FromBrowserContext(process->GetBrowserContext());
+      if (!profile_->IsSameProfile(profile))
+        return;
+      if (ScriptsReady()) {
+        SendUpdate(process,

[Devlin, 2014/07/30 21:20:38]

(This comment is in a random spot)

To me, this whole class hierarchy seems a bit ugly.  In particular, it's very
difficult to tell what's each class is doing.  Can we clean this up?  In
particular, try to avoid the use of protected member variables and code that
looks a lot alike (for instance, the code here and in
DeclarativeUserScriptMaster::Observe is very similar).

If there's only a small change in the two methods (for instance, in StartLoad()
it looks like the biggest change is the scripts we pass), it's typically fairly
easy to just factor that small piece into a helper method, like
GetScriptsToLoad(), which each implementation can override, rather than the full
method.

This is pretty vague, so if you want more specifics on how we might be able to
clean this up, lemme know and we'll work it out.

+                   GetSharedMemory(),
+                   std::set<std::string>());  // Include all extensions.
+      }
+      break;
+    }
+    default:
+      DCHECK(false);
+  }
+
+  if (should_start_load) {
+    if (is_loading())
+      pending_load_ = true;
+    else
+      StartLoad();
+  }
+}
+
+void SharedUserScriptMaster::StartLoad() {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+  DCHECK(!is_loading());
+
+  // Remove any user scripts belonging to any extension that was updated or
+  // removed.
+  for (UserScriptList::iterator iter = user_scripts_->begin();
+       iter != user_scripts_->end();) {
+    if (removed_extensions_.count(iter->extension_id()) > 0 ||
+        added_extensions_.count(iter->extension_id()) > 0) {
+      iter = user_scripts_->erase(iter);
+    } else {
+      ++iter;
+    }
+  }
+
+  // Add any content scripts for extensions that were recently loaded.
+  const ExtensionSet& enabled_extensions =
+      ExtensionRegistry::Get(profile_)->enabled_extensions();
+  for (std::set<std::string>::const_iterator iter = added_extensions_.begin();
+       iter != added_extensions_.end();
+       ++iter) {
+    const Extension* extension = enabled_extensions.GetByID(*iter);
+    if (!extension)
+      continue;
+    bool incognito_enabled =
+        util::IsIncognitoEnabled(extension->id(), profile_);
+    const UserScriptList& scripts =
+        ContentScriptsInfo::GetContentScripts(extension);
+    for (UserScriptList::const_iterator script = scripts.begin();
+         script != scripts.end();
+         ++script) {
+      user_scripts_->push_back(*script);
+      user_scripts_->back().set_incognito_enabled(incognito_enabled);
+    }
+  }
+
+  content::BrowserThread::PostTask(
+      content::BrowserThread::FILE,
+      FROM_HERE,
+      base::Bind(&UserScriptMaster::LoadScriptsOnFileThread,
+                 base::Passed(&user_scripts_),
+                 extensions_info_,
+                 added_extensions_,
+                 make_scoped_refptr(
+                     ExtensionSystem::Get(profile_)->content_verifier()),
+                 base::Bind(&UserScriptMaster::OnScriptsLoaded,
+                            weak_factory_.GetWeakPtr())));
+  added_extensions_.clear();
+  removed_extensions_.clear();
+  user_scripts_.reset(NULL);
+}
+
+}  // namespace extensions