Take the snapshot if the thumbnail cache returns empty.

To avoid Recents thumbnail being empty, a snapshot is triggered if no
cache exists.

Bug: 191272693
Test: manually test with Exo (Host apps on virtual display.) to check if
the Recents displays non-empty thumbnail.

Change-Id: I2a898d5127e18e6209ff236d3a72aa22c2a0ca82

5 files changed, 20 insertions, 9 deletions

diff --git a/core/java/android/app/IActivityTaskManager.aidl b/core/java/android/app/IActivityTaskManager.aidl
index fe75dd302beb..dc6825c85705 100644
--- a/core/java/android/app/IActivityTaskManager.aidl
+++ b/core/java/android/app/IActivityTaskManager.aidl
@@ -263,9 +263,12 @@ interface IActivityTaskManager {
      * @param taskId the id of the task to retrieve the sAutoapshots for
      * @param isLowResolution if set, if the snapshot needs to be loaded from disk, this will load
      *                          a reduced resolution of it, which is much faster
+     * @param takeSnapshotIfNeeded if set, call {@link #takeTaskSnapshot} to trigger the snapshot
+                                   if no cache exists.
      * @return a graphic buffer representing a screenshot of a task
      */
-    android.window.TaskSnapshot getTaskSnapshot(int taskId, boolean isLowResolution);
+    android.window.TaskSnapshot getTaskSnapshot(
+            int taskId, boolean isLowResolution, boolean takeSnapshotIfNeeded);
 
     /**
      * @param taskId the id of the task to take a snapshot of
diff --git a/libs/WindowManager/Shell/src/com/android/wm/shell/pip/PipUtils.java b/libs/WindowManager/Shell/src/com/android/wm/shell/pip/PipUtils.java
index dc60bcf742ce..29434f73e84b 100644
--- a/libs/WindowManager/Shell/src/com/android/wm/shell/pip/PipUtils.java
+++ b/libs/WindowManager/Shell/src/com/android/wm/shell/pip/PipUtils.java
@@ -116,7 +116,7 @@ public class PipUtils {
         if (taskId <= 0) return null;
         try {
             return ActivityTaskManager.getService().getTaskSnapshot(
-                    taskId, isLowResolution);
+                    taskId, isLowResolution, false /* takeSnapshotIfNeeded */);
         } catch (RemoteException e) {
             Log.e(TAG, "Failed to get task snapshot, taskId=" + taskId, e);
             return null;
diff --git a/packages/SystemUI/shared/src/com/android/systemui/shared/system/ActivityManagerWrapper.java b/packages/SystemUI/shared/src/com/android/systemui/shared/system/ActivityManagerWrapper.java
index be3dfdcf05d5..c5beaa7ee0b1 100644
--- a/packages/SystemUI/shared/src/com/android/systemui/shared/system/ActivityManagerWrapper.java
+++ b/packages/SystemUI/shared/src/com/android/systemui/shared/system/ActivityManagerWrapper.java
@@ -137,12 +137,14 @@ public class ActivityManagerWrapper {
     }
 
     /**
-     * @return the task snapshot for the given {@param taskId}.
+     * @return a {@link ThumbnailData} with {@link TaskSnapshot} for the given {@param taskId}.
+     *         The snapshot will be triggered if no cached {@link TaskSnapshot} exists.
      */
     public @NonNull ThumbnailData getTaskThumbnail(int taskId, boolean isLowResolution) {
         TaskSnapshot snapshot = null;
         try {
-            snapshot = getService().getTaskSnapshot(taskId, isLowResolution);
+            snapshot = getService().getTaskSnapshot(taskId, isLowResolution,
+                    true /* takeSnapshotIfNeeded */);
         } catch (RemoteException e) {
             Log.w(TAG, "Failed to retrieve task snapshot", e);
         }
diff --git a/services/core/java/com/android/server/wm/ActivityTaskManagerService.java b/services/core/java/com/android/server/wm/ActivityTaskManagerService.java
index 7bc551b2aacc..5ae0f4722a20 100644
--- a/services/core/java/com/android/server/wm/ActivityTaskManagerService.java
+++ b/services/core/java/com/android/server/wm/ActivityTaskManagerService.java
@@ -3668,7 +3668,8 @@ public class ActivityTaskManagerService extends IActivityTaskManager.Stub {
     }
 
     @Override
-    public TaskSnapshot getTaskSnapshot(int taskId, boolean isLowResolution) {
+    public TaskSnapshot getTaskSnapshot(int taskId, boolean isLowResolution,
+            boolean takeSnapshotIfNeeded) {
         mAmInternal.enforceCallingPermission(READ_FRAME_BUFFER, "getTaskSnapshot()");
         final long ident = Binder.clearCallingIdentity();
         try {
@@ -3682,8 +3683,12 @@ public class ActivityTaskManagerService extends IActivityTaskManager.Stub {
                 }
             }
             // Don't call this while holding the lock as this operation might hit the disk.
-            return mWindowManager.mTaskSnapshotController.getSnapshot(taskId, task.mUserId,
-                    true /* restoreFromDisk */, isLowResolution);
+            TaskSnapshot taskSnapshot = mWindowManager.mTaskSnapshotController.getSnapshot(taskId,
+                    task.mUserId, true /* restoreFromDisk */, isLowResolution);
+            if (taskSnapshot == null && takeSnapshotIfNeeded) {
+                taskSnapshot = takeTaskSnapshot(taskId);
+            }
+            return taskSnapshot;
         } finally {
             Binder.restoreCallingIdentity(ident);
         }
@@ -6656,7 +6661,8 @@ public class ActivityTaskManagerService extends IActivityTaskManager.Stub {
         @Override
         public TaskSnapshot getTaskSnapshotBlocking(
                 int taskId, boolean isLowResolution) {
-            return ActivityTaskManagerService.this.getTaskSnapshot(taskId, isLowResolution);
+            return ActivityTaskManagerService.this.getTaskSnapshot(taskId, isLowResolution,
+                    false /* takeSnapshotIfNeeded */);
         }
 
         @Override
diff --git a/services/tests/wmtests/src/com/android/server/wm/RecentTasksTest.java b/services/tests/wmtests/src/com/android/server/wm/RecentTasksTest.java
index 1708ed7d4686..83f375f85fa3 100644
--- a/services/tests/wmtests/src/com/android/server/wm/RecentTasksTest.java
+++ b/services/tests/wmtests/src/com/android/server/wm/RecentTasksTest.java
@@ -1332,7 +1332,7 @@ public class RecentTasksTest extends WindowTestsBase {
         });
         assertSecurityException(expectCallable,
                 () -> mAtm.startActivityFromRecents(0, new Bundle()));
-        assertSecurityException(expectCallable, () -> mAtm.getTaskSnapshot(0, true));
+        assertSecurityException(expectCallable, () -> mAtm.getTaskSnapshot(0, true, false));
         assertSecurityException(expectCallable, () -> mAtm.registerTaskStackListener(null));
         assertSecurityException(expectCallable,
                 () -> mAtm.unregisterTaskStackListener(null));