Athena: Adding basic resource management framework (un-/re-loading) of V2 applications

athena/content/app_activity_registry.cc

Index: athena/content/app_activity_registry.cc
diff --git a/athena/content/app_activity_registry.cc b/athena/content/app_activity_registry.cc
new file mode 100644
index 0000000000000000000000000000000000000000..dc7bce9c75cc97245faa1de253f35045ae16d6a6
--- /dev/null
+++ b/athena/content/app_activity_registry.cc
@@ -0,0 +1,146 @@
+// 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 "athena/content/app_activity_registry.h"
+
+#include "athena/activity/public/activity_manager.h"
+#include "athena/content/app_activity.h"
+#include "athena/content/app_activity_proxy.h"
+#include "athena/content/public/app_content_control_delegate.h"
+#include "athena/content/public/app_registry.h"
+#include "ui/aura/window.h"
+#include "ui/views/view.h"
+#include "ui/views/widget/widget.h"
+
+namespace athena {
+
+AppActivityRegistry::AppActivityRegistry(
+    const std::string& app_id,
+    content::BrowserContext* browser_context) :
+      app_id_(app_id),
+      browser_context_(browser_context),
+      unloaded_activity_proxy_(NULL) {}
+
+AppActivityRegistry::~AppActivityRegistry() {
+  CHECK(activity_list_.empty());
+  if (unloaded_activity_proxy_)
+    ActivityManager::Get()->RemoveActivity(unloaded_activity_proxy_);
+  DCHECK(!unloaded_activity_proxy_);
+}
+
+void AppActivityRegistry::RegisterAppActivity(AppActivity* app_activity) {
+  if (unloaded_activity_proxy_) {
+    // Since we add an application window, the activity isn't unloaded anymore.
+    ActivityManager::Get()->RemoveActivity(unloaded_activity_proxy_);
+    // With the removal the object should have been deleted and we should have
+    // been informed of the object's destruction.
+    DCHECK(!unloaded_activity_proxy_);
+  }
+  // The same window should never be added twice.
+  CHECK(std::find(activity_list_.begin(),
+                  activity_list_.end(),
+                  app_activity) == activity_list_.end());
+  activity_list_.push_back(app_activity);
+}
+
+void AppActivityRegistry::UnregisterAppActivity(AppActivity* app_activity) {
+  // It is possible that a detach gets called without ever being attached.
+  std::vector<AppActivity*>::iterator it =
+      std::find(activity_list_.begin(), activity_list_.end(), app_activity);
+  if (it == activity_list_.end())
+    return;
+
+  activity_list_.erase(it);
+  // When the last window gets destroyed and there is no proxy to restart, we
+  // delete ourselves.
+  if (activity_list_.empty() && !unloaded_activity_proxy_) {
+    AppRegistry::Get()->RemoveAppActivityRegistry(this);
+    // after this call this object should be gone.
+  }
+}
+
+AppActivity* AppActivityRegistry::GetAppActivityAt(size_t index) {
+  if (index >= activity_list_.size())
+    return NULL;
+  return activity_list_[index];
+}
+
+void AppActivityRegistry::Unload() {
+  CHECK(!unloaded_activity_proxy_);
+  DCHECK(!activity_list_.empty());
+
+  // In order to allow an entire application to unload we require that all of
+  // its activities are marked as unloaded.
+  for (std::vector<AppActivity*>::iterator it = activity_list_.begin();
+       it != activity_list_.end(); ++it) {
+    if ((*it)->GetCurrentState() != Activity::ACTIVITY_UNLOADED)
+      return;
+  }
+
+  // Create an activity proxy which can be used to re-activate the app. Insert
+  // the proxy then into the activity stream at the location of the (newest)
+  // current activity.
+  unloaded_activity_proxy_ =
+      new AppActivityProxy(activity_list_[0]->GetActivityViewModel(), this);
+  ActivityManager::Get()->AddActivity(unloaded_activity_proxy_);
+  // The new activity should be in the place of the most recently used app
+  // window. To get it there, we get the most recently used application window
+  // and place the proxy activities window in front or behind, so that when the
+  // activity disappears it takes its place.
+  MoveBeforeMruApplicationWindow(unloaded_activity_proxy_->GetWindow());
+
+  // Unload the application. This operation will be asynchronous.
+  if (!AppRegistry::Get()->GetDelegate()->UnloadApplication(app_id_,
+                                                            browser_context_)) {
+    while(!activity_list_.empty())
+      delete activity_list_.back();
+  }
+}
+
+void AppActivityRegistry::ProxyDestroyed(AppActivityProxy* proxy) {
+  DCHECK_EQ(unloaded_activity_proxy_, proxy);
+  unloaded_activity_proxy_ = NULL;
+  if (activity_list_.empty()) {
+    AppRegistry::Get()->RemoveAppActivityRegistry(this);
+    // |This| is gone now.
+  }
+}
+
+void AppActivityRegistry::RestartApplication(AppActivityProxy* proxy) {
+  DCHECK_EQ(unloaded_activity_proxy_, proxy);
+  // Restart the application.
+  AppRegistry::Get()->GetDelegate()->RestartApplication(app_id_,
+                                                        browser_context_);
+  // Remove the activity from the Activity manager.
+  ActivityManager::Get()->RemoveActivity(unloaded_activity_proxy_);
+  delete unloaded_activity_proxy_;  // Will call ProxyDestroyed.
+  // After this call |this| might be gone if the app did not open a window yet.
+}
+
+void AppActivityRegistry::MoveBeforeMruApplicationWindow(aura::Window* window) {
+  DCHECK(activity_list_.size());
+  // TODO(skuhne): This needs to be changed to some kind of delegate which
+  // resides in the window manager.
+  const aura::Window::Windows children =
+      activity_list_[0]->GetWindow()->parent()->children();;
+  // Find the first window in the container which is part of the application.
+  for (aura::Window::Windows::const_iterator child_iterator = children.begin();
+      child_iterator != children.end(); ++child_iterator) {
+    for (std::vector<AppActivity*>::iterator app_iterator =
+             activity_list_.begin();
+         app_iterator != activity_list_.end(); ++app_iterator) {
+      if (*child_iterator == (*app_iterator)->GetWindow()) {
+        // Since "StackChildBelow" does not change the order if the window
+        // if the window is below - but not immediately behind - the target
+        // window, we re-stack both ways.
+        window->parent()->StackChildBelow(window, *child_iterator);
+        window->parent()->StackChildBelow(*child_iterator, window);
+        return;
+      }
+    }
+  }
+  NOTREACHED() << "The application does not get tracked by the mru list";
+}
+
+}  // namespace athena