Fix erroneous self deletion on SkImage creation failure

TL;DR: Skia should always call releaseProc, and maybe sooner than we thought.

There are multiple scenarios where SkImage:MakeFromTexture will fail,
returning a nullptr and calling releaseProc due to a RefCntedCallback
falling out of scope. Previously this could cause mUsageCount to fall to
0, resulting in the AutoBackendTextureRelease deleting itself even
though DeferredLayerUpdater owned a ref and expected it to still exist.

Also added logging for some reasons that could cause the later call to
MakeFromTexture to fail.

Bug: b/246831853
Test: hwui_unit_tests
Change-Id: I7fd2566b9a85fe286f72b0fc42eba5450cac69b0
Merged-In: I7fd2566b9a85fe286f72b0fc42eba5450cac69b0

libs/hwui/Android.bp

@@ -674,6 +674,7 @@ cc_test {
     srcs: [
         "tests/unit/main.cpp",
         "tests/unit/ABitmapTests.cpp",
+        "tests/unit/AutoBackendTextureReleaseTests.cpp",
         "tests/unit/CacheManagerTests.cpp",
         "tests/unit/CanvasContextTests.cpp",
         "tests/unit/CanvasOpTests.cpp",

libs/hwui/AutoBackendTextureRelease.cpp

@@ -32,9 +32,17 @@ AutoBackendTextureRelease::AutoBackendTextureRelease(GrDirectContext* context,
     bool createProtectedImage = 0 != (desc.usage & AHARDWAREBUFFER_USAGE_PROTECTED_CONTENT);
     GrBackendFormat backendFormat =
             GrAHardwareBufferUtils::GetBackendFormat(context, buffer, desc.format, false);
+    LOG_ALWAYS_FATAL_IF(!backendFormat.isValid(),
+                        __FILE__ " Invalid GrBackendFormat. GrBackendApi==%" PRIu32
+                                 ", AHardwareBuffer_Format==%" PRIu32 ".",
+                        static_cast<int>(context->backend()), desc.format);
     mBackendTexture = GrAHardwareBufferUtils::MakeBackendTexture(
             context, buffer, desc.width, desc.height, &mDeleteProc, &mUpdateProc, &mImageCtx,
             createProtectedImage, backendFormat, false);
+    LOG_ALWAYS_FATAL_IF(!mBackendTexture.isValid(),
+                        __FILE__ " Invalid GrBackendTexture. Width==%" PRIu32 ", height==%" PRIu32
+                                 ", protected==%d",
+                        desc.width, desc.height, createProtectedImage);
 }
 
 void AutoBackendTextureRelease::unref(bool releaseImage) {
@@ -74,13 +82,13 @@ void AutoBackendTextureRelease::makeImage(AHardwareBuffer* buffer,
     AHardwareBuffer_Desc desc;
     AHardwareBuffer_describe(buffer, &desc);
     SkColorType colorType = GrAHardwareBufferUtils::GetSkColorTypeFromBufferFormat(desc.format);
+    // The following ref will be counteracted by Skia calling releaseProc, either during
+    // MakeFromTexture if there is a failure, or later when SkImage is discarded. It must
+    // be called before MakeFromTexture, otherwise Skia may remove HWUI's ref on failure.
+    ref();
     mImage = SkImage::MakeFromTexture(
             context, mBackendTexture, kTopLeft_GrSurfaceOrigin, colorType, kPremul_SkAlphaType,
             uirenderer::DataSpaceToColorSpace(dataspace), releaseProc, this);
-    if (mImage.get()) {
-        // The following ref will be counteracted by releaseProc, when SkImage is discarded.
-        ref();
-    }
 }
 
 void AutoBackendTextureRelease::newBufferContent(GrDirectContext* context) {

libs/hwui/AutoBackendTextureRelease.h

@@ -25,6 +25,9 @@
 namespace android {
 namespace uirenderer {
 
+// Friend TestUtils serves as a proxy for any test cases that require access to private members.
+class TestUtils;
+
 /**
  * AutoBackendTextureRelease manages EglImage/VkImage lifetime. It is a ref-counted object
  * that keeps GPU resources alive until the last SkImage object using them is destroyed.
@@ -66,6 +69,9 @@ private:
 
     // mImage is the SkImage created from mBackendTexture.
     sk_sp<SkImage> mImage;
+
+    // Friend TestUtils serves as a proxy for any test cases that require access to private members.
+    friend class TestUtils;
 };
 
 } /* namespace uirenderer */

libs/hwui/tests/common/TestUtils.h

@@ -16,6 +16,7 @@
 
 #pragma once
 
+#include <AutoBackendTextureRelease.h>
 #include <DisplayList.h>
 #include <Matrix.h>
 #include <Properties.h>
@@ -283,6 +284,11 @@ public:
     static SkRect getClipBounds(const SkCanvas* canvas);
     static SkRect getLocalClipBounds(const SkCanvas* canvas);
 
+    static int getUsageCount(const AutoBackendTextureRelease* textureRelease) {
+        EXPECT_NE(nullptr, textureRelease);
+        return textureRelease->mUsageCount;
+    }
+
     struct CallCounts {
         int sync = 0;
         int contextDestroyed = 0;

libs/hwui/tests/unit/AutoBackendTextureReleaseTests.cpp

@@ -0,0 +1,73 @@
+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <gtest/gtest.h>
+
+#include "AutoBackendTextureRelease.h"
+#include "tests/common/TestUtils.h"
+
+using namespace android;
+using namespace android::uirenderer;
+
+AHardwareBuffer* allocHardwareBuffer() {
+    AHardwareBuffer* buffer;
+    AHardwareBuffer_Desc desc = {
+            .width = 16,
+            .height = 16,
+            .layers = 1,
+            .format = AHARDWAREBUFFER_FORMAT_R8G8B8A8_UNORM,
+            .usage = AHARDWAREBUFFER_USAGE_CPU_READ_RARELY | AHARDWAREBUFFER_USAGE_CPU_WRITE_RARELY,
+    };
+    constexpr int kSucceeded = 0;
+    int status = AHardwareBuffer_allocate(&desc, &buffer);
+    EXPECT_EQ(kSucceeded, status);
+    return buffer;
+}
+
+// Expands to AutoBackendTextureRelease_makeImage_invalid_RenderThreadTest,
+// set as friend in AutoBackendTextureRelease.h
+RENDERTHREAD_TEST(AutoBackendTextureRelease, makeImage_invalid) {
+    AHardwareBuffer* buffer = allocHardwareBuffer();
+    AutoBackendTextureRelease* textureRelease =
+            new AutoBackendTextureRelease(renderThread.getGrContext(), buffer);
+
+    EXPECT_EQ(1, TestUtils::getUsageCount(textureRelease));
+
+    // SkImage::MakeFromTexture should fail if given null GrDirectContext.
+    textureRelease->makeImage(buffer, HAL_DATASPACE_UNKNOWN, /*context = */ nullptr);
+
+    EXPECT_EQ(1, TestUtils::getUsageCount(textureRelease));
+
+    textureRelease->unref(true);
+    AHardwareBuffer_release(buffer);
+}
+
+// Expands to AutoBackendTextureRelease_makeImage_valid_RenderThreadTest,
+// set as friend in AutoBackendTextureRelease.h
+RENDERTHREAD_TEST(AutoBackendTextureRelease, makeImage_valid) {
+    AHardwareBuffer* buffer = allocHardwareBuffer();
+    AutoBackendTextureRelease* textureRelease =
+            new AutoBackendTextureRelease(renderThread.getGrContext(), buffer);
+
+    EXPECT_EQ(1, TestUtils::getUsageCount(textureRelease));
+
+    textureRelease->makeImage(buffer, HAL_DATASPACE_UNKNOWN, renderThread.getGrContext());
+
+    EXPECT_EQ(2, TestUtils::getUsageCount(textureRelease));
+
+    textureRelease->unref(true);
+    AHardwareBuffer_release(buffer);
+}