From 1c5481ea27625ae9ecb2f386bc115d479fdf50c4 Mon Sep 17 00:00:00 2001
From: Robert Carr <racarr@google.com>
Date: Mon, 1 Jul 2019 14:42:27 -0700
Subject: SurfaceFlinger: Hide Z order relatives when relativeOf is
 hiddenByPolicy.

Now that we are using relative Z for the SurfaceView background we
encounter yet another edge case. During Surface preservation we reparent
the SurfaceView from one WindowStateAnimator to a second. When we reparent
it we hide the old surface and show the new one. However at this time
the background is still relative to the OLD surface, which is Z ordered
on top of the new Surface. To fix this we ensure that if a layers relative
Z parent is hidden by policy the layer is also invisible.

Bug: 136061599
Test: TransactionTest#HideRelativeParentHidesLayer
Change-Id: I941fb9060dab79dba89300a5c86d6ea1a69f577d
---
 services/surfaceflinger/Layer.cpp                  | 10 ++++-
 services/surfaceflinger/Layer.h                    |  2 +-
 services/surfaceflinger/tests/Transaction_test.cpp | 50 ++++++++++++++++++++++
 3 files changed, 60 insertions(+), 2 deletions(-)

diff --git a/services/surfaceflinger/Layer.cpp b/services/surfaceflinger/Layer.cpp
index bda7e4308f..1318bc0b2a 100644
--- a/services/surfaceflinger/Layer.cpp
+++ b/services/surfaceflinger/Layer.cpp
@@ -1231,6 +1231,14 @@ bool Layer::isHiddenByPolicy() const {
     if (parent != nullptr && parent->isHiddenByPolicy()) {
         return true;
     }
+    if (usingRelativeZ(LayerVector::StateSet::Drawing)) {
+        auto zOrderRelativeOf = mDrawingState.zOrderRelativeOf.promote();
+        if (zOrderRelativeOf != nullptr) {
+            if (zOrderRelativeOf->isHiddenByPolicy()) {
+                return true;
+            }
+        }
+    }
     return s.flags & layer_state_t::eLayerHidden;
 }
 
@@ -1612,7 +1620,7 @@ int32_t Layer::getZ() const {
     return mDrawingState.z;
 }
 
-bool Layer::usingRelativeZ(LayerVector::StateSet stateSet) {
+bool Layer::usingRelativeZ(LayerVector::StateSet stateSet) const {
     const bool useDrawing = stateSet == LayerVector::StateSet::Drawing;
     const State& state = useDrawing ? mDrawingState : mCurrentState;
     return state.zOrderRelativeOf != nullptr;
diff --git a/services/surfaceflinger/Layer.h b/services/surfaceflinger/Layer.h
index 5c55111b40..8a80e15f29 100644
--- a/services/surfaceflinger/Layer.h
+++ b/services/surfaceflinger/Layer.h
@@ -824,7 +824,7 @@ public:
 
 protected:
     // -----------------------------------------------------------------------
-    bool usingRelativeZ(LayerVector::StateSet stateSet);
+    bool usingRelativeZ(LayerVector::StateSet stateSet) const;
 
     bool mPremultipliedAlpha{true};
     String8 mName;
diff --git a/services/surfaceflinger/tests/Transaction_test.cpp b/services/surfaceflinger/tests/Transaction_test.cpp
index f83b3eafe6..d5f65348d8 100644
--- a/services/surfaceflinger/tests/Transaction_test.cpp
+++ b/services/surfaceflinger/tests/Transaction_test.cpp
@@ -1115,6 +1115,56 @@ TEST_P(LayerTypeTransactionTest, SetLayerAndRelative) {
     }
 }
 
+TEST_P(LayerTypeTransactionTest, HideRelativeParentHidesLayer) {
+    sp<SurfaceControl> parent =
+            LayerTransactionTest::createLayer("Parent", 0 /* buffer width */, 0 /* buffer height */,
+                                              ISurfaceComposerClient::eFXSurfaceColor);
+    sp<SurfaceControl> relativeParent =
+            LayerTransactionTest::createLayer("RelativeParent", 0 /* buffer width */,
+                    0 /* buffer height */, ISurfaceComposerClient::eFXSurfaceColor);
+
+    sp<SurfaceControl> childLayer;
+    ASSERT_NO_FATAL_FAILURE(
+            childLayer = LayerTransactionTest::createLayer("childLayer", 0 /* buffer width */,
+                                                           0 /* buffer height */,
+                                                           ISurfaceComposerClient::eFXSurfaceColor,
+                                                           parent.get()));
+    Transaction()
+            .setColor(childLayer, half3{1.0f, 0.0f, 0.0f})
+            .setColor(parent, half3{0.0f, 0.0f, 0.0f})
+            .setColor(relativeParent, half3{0.0f, 1.0f, 0.0f})
+            .show(childLayer)
+            .show(parent)
+            .show(relativeParent)
+            .setLayer(parent, mLayerZBase - 1)
+            .setLayer(relativeParent, mLayerZBase)
+            .apply();
+
+    Transaction()
+            .setRelativeLayer(childLayer, relativeParent->getHandle(), 1)
+            .apply();
+
+    {
+        SCOPED_TRACE("setLayer above");
+        // Set layer should get applied and place the child above.
+        std::unique_ptr<ScreenCapture> screenshot;
+        ScreenCapture::captureScreen(&screenshot);
+        screenshot->expectColor(Rect(0, 0, 20, 30), Color::RED);
+    }
+
+    Transaction()
+        .hide(relativeParent)
+        .apply();
+
+    {
+        SCOPED_TRACE("hide relative parent");
+        // The relative should no longer be visible.
+        std::unique_ptr<ScreenCapture> screenshot;
+        ScreenCapture::captureScreen(&screenshot);
+        screenshot->expectColor(Rect(0, 0, 20, 30), Color::BLACK);
+    }
+}
+
 void LayerRenderTypeTransactionTest::setRelativeZGroupHelper(uint32_t layerType) {
     sp<SurfaceControl> layerR;
     sp<SurfaceControl> layerG;
-- 
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