commit b8aaea16b889ef4859138cc528986551001f3add
author David Sodman <dsodman@google.com> Thu Dec 14 15:54:51 2017 -0800
committer David Sodman <dsodman@google.com> Thu Aug 09 19:07:19 2018 -0700
tree 076d4aa5b8f4fc3cfea4a39beea17659e68acfa1
parent f4c8f3869475239fc2105d557b5f3527360c31c2

SF: use shared_ptr to track hwcLayer

Use std::shared_ptr to track hwcLayer pointers.
This is necessary because the calculation of
data for HWComposer is done in Layer and the processing of that
data is done in SurfaceFlinger, and we need to make sure that
the hwcLayer is not destroyed by Layer while or before being
used by SurfaceFlinger.

Bug: 112259502
Test: cts -m CtsViewTestCases
      SurfaceFlinger_test
      vrflinger_test

Change-Id: I683dd071efbeebd9a9941053183daf4efb88469e

services/surfaceflinger/Layer.cpp

diff --git a/services/surfaceflinger/Layer.cpp b/services/surfaceflinger/Layer.cpp
index ee9ee78..fef53bb 100644
--- a/services/surfaceflinger/Layer.cpp
+++ b/services/surfaceflinger/Layer.cpp
@@ -230,7 +230,10 @@
 bool Layer::createHwcLayer(HWComposer* hwc, int32_t displayId) {
     LOG_ALWAYS_FATAL_IF(getBE().mHwcLayers.count(displayId) != 0,
                         "Already have a layer for display %d", displayId);
-    HWC2::Layer* layer = hwc->createLayer(displayId);
+    auto layer = std::shared_ptr<HWC2::Layer>(
+            hwc->createLayer(displayId),
+            [hwc, displayId](HWC2::Layer* layer) {
+               hwc->destroyLayer(displayId, layer); });
     if (!layer) {
         return false;
     }
@@ -249,11 +252,8 @@
     auto& hwcInfo = getBE().mHwcLayers[displayId];
     LOG_ALWAYS_FATAL_IF(hwcInfo.layer == nullptr, "Attempt to destroy null layer");
     LOG_ALWAYS_FATAL_IF(hwcInfo.hwc == nullptr, "Missing HWComposer");
-    hwcInfo.hwc->destroyLayer(displayId, hwcInfo.layer);
-    // The layer destroyed listener should have cleared the entry from
-    // mHwcLayers. Verify that.
-    LOG_ALWAYS_FATAL_IF(getBE().mHwcLayers.count(displayId) != 0,
-                        "Stale layer entry in getBE().mHwcLayers");
+    hwcInfo.layer = nullptr;
+
     return true;
 }
 
@@ -716,7 +716,8 @@
     auto position = displayTransform.transform(frame);
 
     auto error =
-            getBE().mHwcLayers[displayId].layer->setCursorPosition(position.left, position.top);
+            (getBE().mHwcLayers[displayId].layer)->setCursorPosition(
+                    position.left, position.top);
     ALOGE_IF(error != HWC2::Error::None,
              "[%s] Failed to set cursor position "
              "to (%d, %d): %s (%d)",
@@ -759,13 +760,13 @@
     }
     auto& hwcInfo = getBE().mHwcLayers[displayId];
     auto& hwcLayer = hwcInfo.layer;
-    ALOGV("setCompositionType(%" PRIx64 ", %s, %d)", hwcLayer->getId(), to_string(type).c_str(),
+    ALOGV("setCompositionType(%" PRIx64 ", %s, %d)", (hwcLayer)->getId(), to_string(type).c_str(),
           static_cast<int>(callIntoHwc));
     if (hwcInfo.compositionType != type) {
         ALOGV("    actually setting");
         hwcInfo.compositionType = type;
         if (callIntoHwc) {
-            auto error = hwcLayer->setCompositionType(type);
+            auto error = (hwcLayer)->setCompositionType(type);
             ALOGE_IF(error != HWC2::Error::None,
                      "[%s] Failed to set "
                      "composition type %s: %s (%d)",