Merge "Don't allow stacks above pinned stack." into oc-dev
am: 22d4ef008d

Change-Id: I740f62046d5f37a634e8c656ee76a82ecb244ff1
diff --git a/services/core/java/com/android/server/wm/DisplayContent.java b/services/core/java/com/android/server/wm/DisplayContent.java
index 058fdae..1823610 100644
--- a/services/core/java/com/android/server/wm/DisplayContent.java
+++ b/services/core/java/com/android/server/wm/DisplayContent.java
@@ -125,6 +125,7 @@
 import android.view.SurfaceControl;
 import android.view.WindowManagerPolicy;
 
+import com.android.internal.annotations.VisibleForTesting;
 import com.android.internal.util.ToBooleanFunction;
 import com.android.internal.view.IInputMethodClient;
 
@@ -1396,6 +1397,22 @@
         return null;
     }
 
+    @VisibleForTesting
+    int getStackCount() {
+        return mTaskStackContainers.size();
+    }
+
+    @VisibleForTesting
+    int getStaskPosById(int stackId) {
+        for (int i = mTaskStackContainers.size() - 1; i >= 0; --i) {
+            final TaskStack stack = mTaskStackContainers.get(i);
+            if (stack.mStackId == stackId) {
+                return i;
+            }
+        }
+        return -1;
+    }
+
     @Override
     void onConfigurationChanged(Configuration newParentConfig) {
         super.onConfigurationChanged(newParentConfig);
@@ -3274,8 +3291,9 @@
                     : requestedPosition >= topChildPosition;
             int targetPosition = requestedPosition;
 
-            if (toTop && isStackVisible(PINNED_STACK_ID) && stack.mStackId != PINNED_STACK_ID) {
-                // The pinned stack is always the top most stack (always-on-top) when it is visible.
+            if (toTop && stack.mStackId != PINNED_STACK_ID
+                    && getStackById(PINNED_STACK_ID) != null) {
+                // The pinned stack is always the top most stack (always-on-top) when it is present.
                 TaskStack topStack = mChildren.get(topChildPosition);
                 if (topStack.mStackId != PINNED_STACK_ID) {
                     throw new IllegalStateException("Pinned stack isn't top stack??? " + mChildren);
diff --git a/services/tests/servicestests/src/com/android/server/wm/DisplayContentTests.java b/services/tests/servicestests/src/com/android/server/wm/DisplayContentTests.java
index 0270bb9..837ce56 100644
--- a/services/tests/servicestests/src/com/android/server/wm/DisplayContentTests.java
+++ b/services/tests/servicestests/src/com/android/server/wm/DisplayContentTests.java
@@ -16,6 +16,7 @@
 
 package com.android.server.wm;
 
+import static android.app.ActivityManager.StackId.PINNED_STACK_ID;
 import static android.view.Display.DEFAULT_DISPLAY;
 import static android.view.WindowManager.LayoutParams.TYPE_APPLICATION;
 import static android.view.WindowManager.LayoutParams.TYPE_APPLICATION_ATTACHED_DIALOG;
@@ -289,6 +290,24 @@
         verifySizes(sDisplayContent, smallerWidth, smallerHeight, smallerDensity);
     }
 
+    /**
+     * This test enforces that the pinned stack is always kept as the top stack.
+     */
+    @Test
+    public void testPinnedStackLocation() {
+        createStackControllerOnStackOnDisplay(PINNED_STACK_ID, sDisplayContent);
+        final int initialStackCount = sDisplayContent.getStackCount();
+        // Ensure that the pinned stack was placed at the end
+        assertEquals(initialStackCount - 1, sDisplayContent.getStaskPosById(PINNED_STACK_ID));
+        // By default, this should try to create a new stack on top
+        createTaskStackOnDisplay(sDisplayContent);
+        final int afterStackCount = sDisplayContent.getStackCount();
+        // Make sure the stack count has increased
+        assertEquals(initialStackCount + 1, afterStackCount);
+        // Ensure that the pinned stack is still on top
+        assertEquals(afterStackCount - 1, sDisplayContent.getStaskPosById(PINNED_STACK_ID));
+    }
+
     private static void verifySizes(DisplayContent displayContent, int expectedBaseWidth,
                              int expectedBaseHeight, int expectedBaseDensity) {
         assertEquals(displayContent.mBaseDisplayWidth, expectedBaseWidth);