commit a0292284fa4f80b29a7e931209aa535bba54b735
author Vishnu Nair <vishnun@google.com> Sat Dec 16 14:32:00 2023 -0800
committer Vishnu Nair <vishnun@google.com> Sat Dec 16 14:32:38 2023 -0800
tree 7d1b4609310e12bf4ea1176cd0742a6e06473841
parent 8597755c385471ef4bf2286558d381b5ef8c94bb

Detect and recover from relative z loops

The caller can create loops in the hierarchy by relatively
reparenting layers to each other. This can be done directly
or via a chain of layers.

The logic to detect and fix this was not being called. Fix this
by making loop detection a bit harder to ignore and part of
hierarchy builder's update call.

Test: presubmit
Bug: 316236833
Change-Id: I484f9b8e2742fef22a5d76362a715eb6850c26f6

services/surfaceflinger/tests/unittests/LayerHierarchyTest.h

diff --git a/services/surfaceflinger/tests/unittests/LayerHierarchyTest.h b/services/surfaceflinger/tests/unittests/LayerHierarchyTest.h
index 7e9abce..67e6249 100644
--- a/services/surfaceflinger/tests/unittests/LayerHierarchyTest.h
+++ b/services/surfaceflinger/tests/unittests/LayerHierarchyTest.h
@@ -176,14 +176,12 @@
     void destroyLayerHandle(uint32_t id) { mLifecycleManager.onHandlesDestroyed({{id, "test"}}); }
 
     void updateAndVerify(LayerHierarchyBuilder& hierarchyBuilder) {
-        if (mLifecycleManager.getGlobalChanges().test(RequestedLayerState::Changes::Hierarchy)) {
-            hierarchyBuilder.update(mLifecycleManager.getLayers(),
-                                    mLifecycleManager.getDestroyedLayers());
-        }
+        hierarchyBuilder.update(mLifecycleManager);
         mLifecycleManager.commitChanges();
 
         // rebuild layer hierarchy from scratch and verify that it matches the updated state.
-        LayerHierarchyBuilder newBuilder(mLifecycleManager.getLayers());
+        LayerHierarchyBuilder newBuilder;
+        newBuilder.update(mLifecycleManager);
         EXPECT_EQ(getTraversalPath(hierarchyBuilder.getHierarchy()),
                   getTraversalPath(newBuilder.getHierarchy()));
         EXPECT_EQ(getTraversalPathInZOrder(hierarchyBuilder.getHierarchy()),
@@ -512,10 +510,7 @@
     }
 
     void update(LayerSnapshotBuilder& snapshotBuilder) {
-        if (mLifecycleManager.getGlobalChanges().test(RequestedLayerState::Changes::Hierarchy)) {
-            mHierarchyBuilder.update(mLifecycleManager.getLayers(),
-                                     mLifecycleManager.getDestroyedLayers());
-        }
+        mHierarchyBuilder.update(mLifecycleManager);
         LayerSnapshotBuilder::Args args{.root = mHierarchyBuilder.getHierarchy(),
                                         .layerLifecycleManager = mLifecycleManager,
                                         .includeMetadata = false,
@@ -530,7 +525,7 @@
         mLifecycleManager.commitChanges();
     }
 
-    LayerHierarchyBuilder mHierarchyBuilder{{}};
+    LayerHierarchyBuilder mHierarchyBuilder;
 
     DisplayInfos mFrontEndDisplayInfos;
     bool mHasDisplayChanges = false;