Screensaver implementation for ChromeOS.

chrome/browser/chromeos/screensaver/screensaver_controller.cc

Index: chrome/browser/chromeos/screensaver/screensaver_controller.cc
diff --git a/chrome/browser/chromeos/screensaver/screensaver_controller.cc b/chrome/browser/chromeos/screensaver/screensaver_controller.cc
new file mode 100644
index 0000000000000000000000000000000000000000..01934981ebd61f00db7f7d5f8dc17aa0afef6502
--- /dev/null
+++ b/chrome/browser/chromeos/screensaver/screensaver_controller.cc
@@ -0,0 +1,184 @@
+// 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.
+
+#include "chrome/browser/chromeos/screensaver/screensaver_controller.h"
+
+#include "ash/screensaver/screensaver_view.h"
+#include "ash/shell.h"
+#include "ash/wm/user_activity_detector.h"
+#include "base/bind.h"
+#include "base/callback.h"
+#include "base/logging.h"
+#include "chrome/browser/extensions/extension_service.h"
+#include "chrome/browser/extensions/extension_system.h"
+#include "chrome/browser/profiles/profile_manager.h"
+#include "chrome/common/chrome_notification_types.h"
+#include "chrome/common/extensions/extension.h"
+#include "chromeos/dbus/dbus_thread_manager.h"
+#include "chromeos/dbus/power_manager_client.h"
+#include "content/public/browser/notification_service.h"
+
+namespace {
+
+const int kScreensaverTimeoutMinutes = 2;
+
+ExtensionService* GetDefaultExtensionService() {
+  Profile* default_profile = ProfileManager::GetDefaultProfile();
+  DCHECK(default_profile);
+  ExtensionService* service =
+      extensions::ExtensionSystem::Get(default_profile)->extension_service();
+  DCHECK(service);
+
+  return service;
+}
+
+// Find the screensaver extension for the given service, excluding
+// the one with exclude_id.
+std::string FindScreensaverExtension(ExtensionService* service,
+                                     const std::string& exclude_id) {
+  const ExtensionSet* extensions = service->extensions();
+  if (!extensions)
+    return std::string();
+
+  for (ExtensionSet::const_iterator it = extensions->begin();
+      it != extensions->end();
+      ++it) {
+    const extensions::Extension* extension = *it;
+    if (extension &&
+        extension->id() != exclude_id &&
+        extension->HasAPIPermission(extensions::APIPermission::kScreensaver))
+      return extension->id();

[stevenjb, 2013/01/31 23:42:18]

nit: {}

[rkc, 2013/02/01 00:35:45]

Done.

+  }
+
+  return std::string();
+}
+
+void UninstallPreviousScreensavers(const extensions::Extension* current) {
+  Profile* default_profile = ProfileManager::GetDefaultProfile();
+  DCHECK(default_profile);
+  ExtensionService* service =
+      extensions::ExtensionSystem::Get(default_profile)->extension_service();
+  DCHECK(service);
+
+  std::string screensaver_id;
+  while (!(screensaver_id =
+      FindScreensaverExtension(service, current->id())).empty()) {

[stevenjb, 2013/01/31 23:42:18]

Does this compile? I'm not sure what this logic is supposed to be...

[rkc, 2013/02/01 00:35:45]

This is fairly standard C++ syntax. It is equivalent to,
screensaver_id = FindScreensaverExtension(service, current->id());
while (!screensaver_id.empty()) {
  screensaver_id = FindScreensaverExtension(service, current->id());
  ...
}

It simplifies the above code into one line.


I've compiled and tested this code manually. The browsertest also tests this
code.

[stevenjb, 2013/02/01 04:16:27]

Ahhh.... I'm familiar with the pattern, but I completely missed the .empty() at
the end of the line.

On the one hand I should have seen that, on the other, it is a bit hard to
parse. Maybe consider:

while ((screensaver_id = FindScreensaverExtension(service, current->id()))
        != "") {
}
or put the .empty() on the second line instead? It's fine as-is, but it clearly
confused me :)

[rkc, 2013/02/01 08:37:39]

Done.

+    string16 error;
+    if (!service->UninstallExtension(screensaver_id, false, &error))
+      LOG(ERROR) <<
+          "Couldn't uninstall previous screensaver extension with id: " <<
+          screensaver_id << " \nError: " << error;

[stevenjb, 2013/01/31 23:42:18]

{}
nit: << at beginning of line

[rkc, 2013/02/01 00:35:45]

Done.

+  }
+}
+
+}  // namespace
+
+namespace chromeos {
+
+ScreensaverController::ScreensaverController()
+    : threshold_(base::TimeDelta::FromMinutes(kScreensaverTimeoutMinutes)),
+      weak_ptr_factory_(ALLOW_THIS_IN_INITIALIZER_LIST(this)) {
+  // Register for extension changes.
+  registrar_.Add(this, chrome::NOTIFICATION_EXTENSION_LOADED,
+                 content::NotificationService::AllSources());
+  registrar_.Add(this, chrome::NOTIFICATION_EXTENSION_UNLOADED,
+                 content::NotificationService::AllSources());
+
+  std::string screensaver_extension_id =
+      FindScreensaverExtension(GetDefaultExtensionService(), std::string());
+  if (!screensaver_extension_id.empty())
+    SetupScreensaver(screensaver_extension_id);
+}
+
+ScreensaverController::~ScreensaverController() {
+  TeardownScreensaver();
+}
+
+void ScreensaverController::Observe(
+    int type,
+    const content::NotificationSource& source,
+    const content::NotificationDetails& details) {
+  switch (type) {
+    case chrome::NOTIFICATION_EXTENSION_INSTALLED: {
+      const extensions::Extension* extension =
+          content::Details<const extensions::Extension>(details).ptr();
+      // Uninstall any previously installed screensaver extensions if a new
+      // screensaver extension is installed.
+      if (extension->HasAPIPermission(extensions::APIPermission::kScreensaver))
+        UninstallPreviousScreensavers(extension);
+      break;
+    }
+    case chrome::NOTIFICATION_EXTENSION_LOADED: {
+      const extensions::Extension* extension =
+          content::Details<const extensions::Extension>(details).ptr();
+      if (!extension->HasAPIPermission(extensions::APIPermission::kScreensaver))
+        return;

[stevenjb, 2013/01/31 23:42:18]

nit: Use either if (HasAPIPermission) {} or if (!HasAPIPermission) return;
consistently here and above

[rkc, 2013/02/01 00:35:45]

Done.

+
+      SetupScreensaver(extension->id());
+      break;
+    }
+    case chrome::NOTIFICATION_EXTENSION_UNLOADED: {
+      const extensions::Extension* extension =
+          content::Details<extensions::UnloadedExtensionInfo>(
+              details)->extension;
+      if (extension->id() == screensaver_extension_id_)
+        TeardownScreensaver();
+      break;
+    }
+  }
+}
+
+void ScreensaverController::IdleNotify(int64 threshold) {
+  ExtensionService* service = GetDefaultExtensionService();
+  const extensions::Extension* screensaver_extension =
+      service->GetExtensionById(screensaver_extension_id_,
+                                ExtensionService::INCLUDE_ENABLED);
+  ash::ShowScreensaver(screensaver_extension->GetFullLaunchURL());
+
+  if (!ash::Shell::GetInstance()->user_activity_detector()->HasObserver(this))
+    ash::Shell::GetInstance()->user_activity_detector()->AddObserver(this);
+}
+
+void ScreensaverController::OnUserActivity() {
+  // We don't want to handle further user notifications; we'll either login
+  // the user and close out or or at least close the screensaver.
+  if (ash::Shell::GetInstance()->user_activity_detector()->HasObserver(this))
+    ash::Shell::GetInstance()->user_activity_detector()->RemoveObserver(this);
+  ash::CloseScreensaver();
+
+  RequestNextIdleNotification();
+}
+
+void ScreensaverController::SetupScreensaver(
+    const std::string& screensaver_extension_id) {
+  screensaver_extension_id_ = screensaver_extension_id;
+
+  PowerManagerClient* power_manager =
+      DBusThreadManager::Get()->GetPowerManagerClient();
+  if (!power_manager->HasObserver(this))
+    power_manager->AddObserver(this);
+
+  RequestNextIdleNotification();
+}
+
+void ScreensaverController::TeardownScreensaver() {
+  PowerManagerClient* power_manager =
+      DBusThreadManager::Get()->GetPowerManagerClient();
+  if (power_manager && power_manager->HasObserver(this))
+    power_manager->RemoveObserver(this);
+
+  if (ash::Shell::GetInstance() &&
+      ash::Shell::GetInstance()->user_activity_detector()->HasObserver(this))
+    ash::Shell::GetInstance()->user_activity_detector()->RemoveObserver(this);

[stevenjb, 2013/01/31 23:42:18]

{}

[rkc, 2013/02/01 00:35:45]

Done.

+
+  ash::CloseScreensaver();
+  screensaver_extension_id_ = "";
+}
+
+void ScreensaverController::RequestNextIdleNotification() {
+  DBusThreadManager::Get()->GetPowerManagerClient()->
+      RequestIdleNotification(threshold_.InMilliseconds());
+}
+
+}  // namespace chromeos