homescreenhandler: keep track of active apps

When the current app window is closed, the current behavior depends on
whether this action terminates the app:
- if the app is terminated, then we switch back to the launcher
- in the other case, we display the background, even if other apps are
  running

In order to implement a better behavior, we should keep track of active
apps and switch back to the previously active one when the current app
window is closed.

Bug-AGL: SPEC-4222
Signed-off-by: Arnaud Ferraris <arnaud.ferraris@collabora.com>
Change-Id: Idf1fe42886e95e2b37349b066204fde002d7c3b5

2 files changed, 30 insertions, 2 deletions

diff --git a/homescreen/src/homescreenhandler.cpp b/homescreen/src/homescreenhandler.cpp
index 4a8b9cd..5ed1fab 100644
--- a/homescreen/src/homescreenhandler.cpp
+++ b/homescreen/src/homescreenhandler.cpp
@@ -89,6 +89,27 @@ activate_app:
     appStarted(application_id);
 }
 
+/*
+ * Keep track of currently running apps and the order in which
+ * they were activated. That way, when an app is closed, we can
+ * switch back to the previously active one.
+ */
+void HomescreenHandler::addAppToStack(const QString& application_id)
+{
+    if (application_id == "homescreen")
+        return;
+
+    if (!apps_stack.contains(application_id)) {
+        apps_stack << application_id;
+    } else {
+        int current_pos = apps_stack.indexOf(application_id);
+        int last_pos = apps_stack.size() - 1;
+
+        if (current_pos != last_pos)
+            apps_stack.move(current_pos, last_pos);
+    }
+}
+
 void HomescreenHandler::appStarted(const QString& application_id)
 {
     struct agl_shell *agl_shell = aglShell->shell.get();
@@ -97,10 +118,14 @@ void HomescreenHandler::appStarted(const QString& application_id)
 
     HMI_DEBUG("HomeScreen", "Activating application %s", application_id.toStdString().c_str());
     agl_shell_activate_app(agl_shell, application_id.toStdString().c_str(), output);
+    addAppToStack(application_id);
 }
 
 void HomescreenHandler::appTerminated(const QString& application_id)
 {
-    HMI_DEBUG("HomeScreen", "Application %s terminated, activating launcher", application_id.toStdString().c_str());
-    appStarted("launcher");
+    HMI_DEBUG("HomeScreen", "Application %s terminated, activating last app", application_id.toStdString().c_str());
+    if (apps_stack.contains(application_id)) {
+        apps_stack.removeOne(application_id);
+        appStarted(apps_stack.last());
+    }
 }
diff --git a/homescreen/src/homescreenhandler.h b/homescreen/src/homescreenhandler.h
index d94740b..503221a 100644
--- a/homescreen/src/homescreenhandler.h
+++ b/homescreen/src/homescreenhandler.h
@@ -48,6 +48,8 @@ public:
     static void onEv_static(const string& event, struct json_object* event_contents);
 #endif
 
+    void addAppToStack(const QString& application_id);
+
 signals:
     void showNotification(QString application_id, QString icon_path, QString text);
     void showInformation(QString info);
@@ -60,6 +62,7 @@ private:
     ApplicationLauncher *mp_launcher;
     Shell *aglShell;
     org::automotivelinux::AppLaunch *applaunch_iface;
+    QStringList apps_stack;
 };
 
 #endif // HOMESCREENHANDLER_H