From 1adc33b5ff527b8c296de0219f8c4e4e31fab871 Mon Sep 17 00:00:00 2001
From: Chavi Weingarten <chaviw@google.com>
Date: Tue, 28 Jun 2022 19:12:46 +0000
Subject: [PATCH] Allow canceled draws to get retried for sync

Apps can cancel draws using the PreDrawListener. When this happens during a sync request, we don't allow another draw to happen since we are trying to avoid multiple draw requests until a sync is complete.

This change makes sure we can draw once before respecting the cancelDraw flag sent from WMS. So even if WMS says it can't draw again, we will allow retries if the cancel happened due to PreDrawListener

Test: Apps that cancel draw don't get stuck during sync
Fixes: 236910512
Change-Id: I67742d03b78306855e258f06c1496b2ba29ca74e
---
 core/java/android/view/ViewRootImpl.java | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/core/java/android/view/ViewRootImpl.java b/core/java/android/view/ViewRootImpl.java
index 64151d9d6c3fb..36f8dd976d690 100644
--- a/core/java/android/view/ViewRootImpl.java
+++ b/core/java/android/view/ViewRootImpl.java
@@ -604,6 +604,8 @@ public final class ViewRootImpl implements ViewParent,
      */
     private boolean mCheckIfCanDraw = false;
 
+    private boolean mDrewOnceForSync = false;
+
     int mSyncSeqId = 0;
     int mLastSyncSeqId = 0;
 
@@ -2991,6 +2993,9 @@ public final class ViewRootImpl implements ViewParent,
                     reportNextDraw();
                     mSyncBuffer = true;
                     isSyncRequest = true;
+                    if (!cancelDraw) {
+                        mDrewOnceForSync = false;
+                    }
                 }
 
                 final boolean surfaceControlChanged =
@@ -3512,9 +3517,11 @@ public final class ViewRootImpl implements ViewParent,
 
         mCheckIfCanDraw = isSyncRequest || cancelDraw;
 
-        boolean cancelAndRedraw = mAttachInfo.mTreeObserver.dispatchOnPreDraw() || cancelDraw;
+        boolean cancelAndRedraw =
+                mAttachInfo.mTreeObserver.dispatchOnPreDraw() || (cancelDraw && mDrewOnceForSync);
         if (!cancelAndRedraw) {
             createSyncIfNeeded();
+            mDrewOnceForSync = true;
         }
 
         if (!isViewVisible) {