From 29ae5b4e5697c7937fab28e70b16075cf094be13 Mon Sep 17 00:00:00 2001
From: Riddle Hsu <riddlehsu@google.com>
Date: Fri, 11 Nov 2022 18:17:26 +0800
Subject: [PATCH] Optimize traversal methods from DisplayArea

There are dozen of display areas won't contain activity or task.
So if a traversal method for task/activity is called on a display
or root, it can be skipped directly. This can save 200+ times to
go through the areas during an activity launch.

Also simplify AR#getDisplayId a bit: no need to use root task.
If the activity is detached, its task will be null. And if the
task is detached, its display will be null.

Bug: 159103089
Test: CtsWindowManagerDeviceTestCases
Change-Id: Iacd20f14bf8681d9ef156721d056bbe5e5a0c3c8
---
 .../com/android/server/wm/ActivityRecord.java |  7 +--
 .../com/android/server/wm/DisplayArea.java    | 49 +++++++++++++++++++
 2 files changed, 51 insertions(+), 5 deletions(-)

diff --git a/services/core/java/com/android/server/wm/ActivityRecord.java b/services/core/java/com/android/server/wm/ActivityRecord.java
index 17a9a63a7f805..711d2296ba307 100644
--- a/services/core/java/com/android/server/wm/ActivityRecord.java
+++ b/services/core/java/com/android/server/wm/ActivityRecord.java
@@ -6912,11 +6912,8 @@ final class ActivityRecord extends WindowToken implements WindowManagerService.A
      *         {@link android.view.Display#INVALID_DISPLAY} if not attached.
      */
     int getDisplayId() {
-        final Task rootTask = getRootTask();
-        if (rootTask == null) {
-            return INVALID_DISPLAY;
-        }
-        return rootTask.getDisplayId();
+        return task != null && task.mDisplayContent != null
+                 ? task.mDisplayContent.mDisplayId : INVALID_DISPLAY;
     }
 
     final boolean isDestroyable() {
diff --git a/services/core/java/com/android/server/wm/DisplayArea.java b/services/core/java/com/android/server/wm/DisplayArea.java
index b84b2d8805dee..bedeabeb6141f 100644
--- a/services/core/java/com/android/server/wm/DisplayArea.java
+++ b/services/core/java/com/android/server/wm/DisplayArea.java
@@ -368,6 +368,55 @@ public class DisplayArea<T extends WindowContainer> extends WindowContainer<T> {
         return null;
     }
 
+    @Override
+    ActivityRecord getActivity(Predicate<ActivityRecord> callback, boolean traverseTopToBottom,
+            ActivityRecord boundary) {
+        if (mType == Type.ABOVE_TASKS || mType == Type.BELOW_TASKS) {
+            return null;
+        }
+        return super.getActivity(callback, traverseTopToBottom, boundary);
+    }
+
+    @Override
+    Task getTask(Predicate<Task> callback, boolean traverseTopToBottom) {
+        if (mType == Type.ABOVE_TASKS || mType == Type.BELOW_TASKS) {
+            return null;
+        }
+        return super.getTask(callback, traverseTopToBottom);
+    }
+
+    @Override
+    boolean forAllActivities(Predicate<ActivityRecord> callback, boolean traverseTopToBottom) {
+        if (mType == Type.ABOVE_TASKS || mType == Type.BELOW_TASKS) {
+            return false;
+        }
+        return super.forAllActivities(callback, traverseTopToBottom);
+    }
+
+    @Override
+    boolean forAllRootTasks(Predicate<Task> callback, boolean traverseTopToBottom) {
+        if (mType == Type.ABOVE_TASKS || mType == Type.BELOW_TASKS) {
+            return false;
+        }
+        return super.forAllRootTasks(callback, traverseTopToBottom);
+    }
+
+    @Override
+    boolean forAllTasks(Predicate<Task> callback) {
+        if (mType == Type.ABOVE_TASKS || mType == Type.BELOW_TASKS) {
+            return false;
+        }
+        return super.forAllTasks(callback);
+    }
+
+    @Override
+    boolean forAllLeafTasks(Predicate<Task> callback) {
+        if (mType == Type.ABOVE_TASKS || mType == Type.BELOW_TASKS) {
+            return false;
+        }
+        return super.forAllLeafTasks(callback);
+    }
+
     @Override
     void forAllDisplayAreas(Consumer<DisplayArea> callback) {
         super.forAllDisplayAreas(callback);