commit 412903fce3a93f411c85c54375a1851bfb370400
author Dan Stoza <stoza@google.com> Thu Apr 27 13:42:17 2017 -0700
committer Dan Stoza <stoza@google.com> Tue May 02 13:34:34 2017 -0700
tree e6f831161b9e544cc81c1f2c9cd7e771644f0e8c
parent 2041913a05b79b96c5c084f30bb8944049a976c8

SurfaceFlinger: Select which layer state to visit

Modifies the traverseIn[Reverse]ZOrder methods to also take an enum
value specifying whether to traverse the current state or the drawing
state.

This has the effect of fixing a bug where we weren't performing
transactions on a child layer because its parent was only visiting its
drawing layers (rather than its current layers) and was thus skipping
the child, which had not yet been moved from current to drawing.

Bug: 36858924
Test: ChildLayerTest.Bug36858924 doesn't hang
Change-Id: I1959f40bc07e77864ba024511d429592a398a67a

services/surfaceflinger/Layer.cpp

diff --git a/services/surfaceflinger/Layer.cpp b/services/surfaceflinger/Layer.cpp
index 406debf..d33d370 100644
--- a/services/surfaceflinger/Layer.cpp
+++ b/services/surfaceflinger/Layer.cpp
@@ -1033,7 +1033,7 @@
         // figure out if there is something below us
         Region under;
         bool finished = false;
-        mFlinger->mDrawingState.layersSortedByZ.traverseInZOrder([&](Layer* layer) {
+        mFlinger->mDrawingState.traverseInZOrder([&](Layer* layer) {
             if (finished || layer == static_cast<Layer const*>(this)) {
                 finished = true;
                 return;
@@ -2519,7 +2519,7 @@
 }
 
 bool Layer::detachChildren() {
-    traverseInZOrder([this](Layer* child) {
+    traverseInZOrder(LayerVector::StateSet::Drawing, [this](Layer* child) {
         if (child == this) {
             return;
         }
@@ -2553,20 +2553,26 @@
     return mDrawingState.z;
 }
 
-LayerVector Layer::makeTraversalList() {
-    if (mDrawingState.zOrderRelatives.size() == 0) {
-        return mDrawingChildren;
+LayerVector Layer::makeTraversalList(LayerVector::StateSet stateSet) {
+    LOG_ALWAYS_FATAL_IF(stateSet == LayerVector::StateSet::Invalid,
+                        "makeTraversalList received invalid stateSet");
+    const bool useDrawing = stateSet == LayerVector::StateSet::Drawing;
+    const LayerVector& children = useDrawing ? mDrawingChildren : mCurrentChildren;
+    const State& state = useDrawing ? mDrawingState : mCurrentState;
+
+    if (state.zOrderRelatives.size() == 0) {
+        return children;
     }
     LayerVector traverse;
 
-    for (const wp<Layer>& weakRelative : mDrawingState.zOrderRelatives) {
+    for (const wp<Layer>& weakRelative : state.zOrderRelatives) {
         sp<Layer> strongRelative = weakRelative.promote();
         if (strongRelative != nullptr) {
             traverse.add(strongRelative);
         }
     }
 
-    for (const sp<Layer>& child : mDrawingChildren) {
+    for (const sp<Layer>& child : children) {
         traverse.add(child);
     }
 
@@ -2576,8 +2582,8 @@
 /**
  * Negatively signed relatives are before 'this' in Z-order.
  */
-void Layer::traverseInZOrder(const std::function<void(Layer*)>& exec) {
-    LayerVector list = makeTraversalList();
+void Layer::traverseInZOrder(LayerVector::StateSet stateSet, const LayerVector::Visitor& visitor) {
+    LayerVector list = makeTraversalList(stateSet);
 
     size_t i = 0;
     for (; i < list.size(); i++) {
@@ -2585,20 +2591,21 @@
         if (relative->getZ() >= 0) {
             break;
         }
-        relative->traverseInZOrder(exec);
+        relative->traverseInZOrder(stateSet, visitor);
     }
-    exec(this);
+    visitor(this);
     for (; i < list.size(); i++) {
         const auto& relative = list[i];
-        relative->traverseInZOrder(exec);
+        relative->traverseInZOrder(stateSet, visitor);
     }
 }
 
 /**
  * Positively signed relatives are before 'this' in reverse Z-order.
  */
-void Layer::traverseInReverseZOrder(const std::function<void(Layer*)>& exec) {
-    LayerVector list = makeTraversalList();
+void Layer::traverseInReverseZOrder(LayerVector::StateSet stateSet,
+                                    const LayerVector::Visitor& visitor) {
+    LayerVector list = makeTraversalList(stateSet);
 
     int32_t i = 0;
     for (i = list.size()-1; i>=0; i--) {
@@ -2606,12 +2613,12 @@
         if (relative->getZ() < 0) {
             break;
         }
-        relative->traverseInReverseZOrder(exec);
+        relative->traverseInReverseZOrder(stateSet, visitor);
     }
-    exec(this);
+    visitor(this);
     for (; i>=0; i--) {
         const auto& relative = list[i];
-        relative->traverseInReverseZOrder(exec);
+        relative->traverseInReverseZOrder(stateSet, visitor);
     }
 }