[Impeller] Introduce mock vulkan context builder (flutter/engine#45834)

This allows us to have better control over the mock context and allows us to test situations like having the validations available, versus not available.

[C++, Objective-C, Java style guides]: https://github.com/flutter/engine/blob/main/CONTRIBUTING.md#style

engine/src/flutter/impeller/renderer/backend/vulkan/blit_command_vk_unittests.cc

@@ -11,7 +11,7 @@ namespace impeller {
 namespace testing {
 
 TEST(BlitCommandVkTest, BlitCopyTextureToTextureCommandVK) {
-  auto context = CreateMockVulkanContext();
+  auto context = MockVulkanContextBuilder().Build();
   auto pool = CommandPoolVK::GetThreadLocal(context.get());
   auto encoder = std::make_unique<CommandEncoderFactoryVK>(context)->Create();
   BlitCopyTextureToTextureCommandVK cmd;
@@ -28,7 +28,7 @@ TEST(BlitCommandVkTest, BlitCopyTextureToTextureCommandVK) {
 }
 
 TEST(BlitCommandVkTest, BlitCopyTextureToBufferCommandVK) {
-  auto context = CreateMockVulkanContext();
+  auto context = MockVulkanContextBuilder().Build();
   auto encoder = std::make_unique<CommandEncoderFactoryVK>(context)->Create();
   BlitCopyTextureToBufferCommandVK cmd;
   cmd.source = context->GetResourceAllocator()->CreateTexture({
@@ -44,7 +44,7 @@ TEST(BlitCommandVkTest, BlitCopyTextureToBufferCommandVK) {
 }
 
 TEST(BlitCommandVkTest, BlitCopyBufferToTextureCommandVK) {
-  auto context = CreateMockVulkanContext();
+  auto context = MockVulkanContextBuilder().Build();
   auto encoder = std::make_unique<CommandEncoderFactoryVK>(context)->Create();
   BlitCopyBufferToTextureCommandVK cmd;
   cmd.destination = context->GetResourceAllocator()->CreateTexture({
@@ -62,7 +62,7 @@ TEST(BlitCommandVkTest, BlitCopyBufferToTextureCommandVK) {
 }
 
 TEST(BlitCommandVkTest, BlitGenerateMipmapCommandVK) {
-  auto context = CreateMockVulkanContext();
+  auto context = MockVulkanContextBuilder().Build();
   auto encoder = std::make_unique<CommandEncoderFactoryVK>(context)->Create();
   BlitGenerateMipmapCommandVK cmd;
   cmd.texture = context->GetResourceAllocator()->CreateTexture({

engine/src/flutter/impeller/renderer/backend/vulkan/command_encoder_vk_unittests.cc

@@ -18,7 +18,7 @@ TEST(CommandEncoderVKTest, DeleteEncoderAfterThreadDies) {
   // command buffers before it cleans up its command pool.
   std::shared_ptr<std::vector<std::string>> called_functions;
   {
-    auto context = CreateMockVulkanContext();
+    auto context = MockVulkanContextBuilder().Build();
     called_functions = GetMockVulkanFunctions(context->GetDevice());
     std::shared_ptr<CommandEncoderVK> encoder;
     std::thread thread([&] {
@@ -46,7 +46,7 @@ TEST(CommandEncoderVKTest, CleanupAfterSubmit) {
   {
     fml::AutoResetWaitableEvent wait_for_submit;
     fml::AutoResetWaitableEvent wait_for_thread_join;
-    auto context = CreateMockVulkanContext();
+    auto context = MockVulkanContextBuilder().Build();
     std::thread thread([&] {
       CommandEncoderFactoryVK factory(context);
       std::shared_ptr<CommandEncoderVK> encoder = factory.Create();

engine/src/flutter/impeller/renderer/backend/vulkan/context_vk_unittests.cc

@@ -14,7 +14,7 @@ TEST(ContextVKTest, DeletesCommandPools) {
   std::weak_ptr<ContextVK> weak_context;
   std::weak_ptr<CommandPoolVK> weak_pool;
   {
-    std::shared_ptr<ContextVK> context = CreateMockVulkanContext();
+    std::shared_ptr<ContextVK> context = MockVulkanContextBuilder().Build();
     std::shared_ptr<CommandPoolVK> pool =
         CommandPoolVK::GetThreadLocal(context.get());
     weak_pool = pool;
@@ -30,7 +30,7 @@ TEST(ContextVKTest, DeletePipelineAfterContext) {
   std::shared_ptr<Pipeline<PipelineDescriptor>> pipeline;
   std::shared_ptr<std::vector<std::string>> functions;
   {
-    std::shared_ptr<ContextVK> context = CreateMockVulkanContext();
+    std::shared_ptr<ContextVK> context = MockVulkanContextBuilder().Build();
     PipelineDescriptor pipeline_desc;
     pipeline_desc.SetVertexDescriptor(std::make_shared<VertexDescriptor>());
     PipelineFuture<PipelineDescriptor> pipeline_future =
@@ -49,7 +49,7 @@ TEST(ContextVKTest, DeleteShaderFunctionAfterContext) {
   std::shared_ptr<const ShaderFunction> shader_function;
   std::shared_ptr<std::vector<std::string>> functions;
   {
-    std::shared_ptr<ContextVK> context = CreateMockVulkanContext();
+    std::shared_ptr<ContextVK> context = MockVulkanContextBuilder().Build();
     PipelineDescriptor pipeline_desc;
     pipeline_desc.SetVertexDescriptor(std::make_shared<VertexDescriptor>());
     std::vector<uint8_t> data = {0x03, 0x02, 0x23, 0x07};
@@ -71,7 +71,7 @@ TEST(ContextVKTest, DeletePipelineLibraryAfterContext) {
   std::shared_ptr<PipelineLibrary> pipeline_library;
   std::shared_ptr<std::vector<std::string>> functions;
   {
-    std::shared_ptr<ContextVK> context = CreateMockVulkanContext();
+    std::shared_ptr<ContextVK> context = MockVulkanContextBuilder().Build();
     PipelineDescriptor pipeline_desc;
     pipeline_desc.SetVertexDescriptor(std::make_shared<VertexDescriptor>());
     pipeline_library = context->GetPipelineLibrary();
@@ -86,9 +86,30 @@ TEST(ContextVKTest, DeletePipelineLibraryAfterContext) {
 TEST(ContextVKTest, CanCreateContextInAbsenceOfValidationLayers) {
   // The mocked methods don't report the presence of a validation layer but we
   // explicitly ask for validation. Context creation should continue anyway.
-  auto context = CreateMockVulkanContext(
-      [](auto& settings) { settings.enable_validation = true; });
+  auto context = MockVulkanContextBuilder()
+                     .SetSettingsCallback([](auto& settings) {
+                       settings.enable_validation = true;
+                     })
+                     .Build();
   ASSERT_NE(context, nullptr);
+  const CapabilitiesVK* capabilites_vk =
+      reinterpret_cast<const CapabilitiesVK*>(context->GetCapabilities().get());
+  ASSERT_FALSE(capabilites_vk->AreValidationsEnabled());
+}
+
+TEST(ContextVKTest, CanCreateContextWithValidationLayers) {
+  auto context =
+      MockVulkanContextBuilder()
+          .SetSettingsCallback(
+              [](auto& settings) { settings.enable_validation = true; })
+          .SetInstanceExtensions(
+              {"VK_KHR_surface", "VK_MVK_macos_surface", "VK_EXT_debug_utils"})
+          .SetInstanceLayers({"VK_LAYER_KHRONOS_validation"})
+          .Build();
+  ASSERT_NE(context, nullptr);
+  const CapabilitiesVK* capabilites_vk =
+      reinterpret_cast<const CapabilitiesVK*>(context->GetCapabilities().get());
+  ASSERT_TRUE(capabilites_vk->AreValidationsEnabled());
 }
 
 }  // namespace testing

engine/src/flutter/impeller/renderer/backend/vulkan/pass_bindings_cache_unittests.cc

@@ -24,7 +24,7 @@ int32_t CountStringViewInstances(const std::vector<std::string>& strings,
 }  // namespace
 
 TEST(PassBindingsCacheTest, bindPipeline) {
-  auto context = CreateMockVulkanContext();
+  auto context = MockVulkanContextBuilder().Build();
   PassBindingsCache cache;
   auto encoder = std::make_unique<CommandEncoderFactoryVK>(context)->Create();
   auto buffer = encoder->GetCommandBuffer();
@@ -38,7 +38,7 @@ TEST(PassBindingsCacheTest, bindPipeline) {
 }
 
 TEST(PassBindingsCacheTest, setStencilReference) {
-  auto context = CreateMockVulkanContext();
+  auto context = MockVulkanContextBuilder().Build();
   PassBindingsCache cache;
   auto encoder = std::make_unique<CommandEncoderFactoryVK>(context)->Create();
   auto buffer = encoder->GetCommandBuffer();
@@ -53,7 +53,7 @@ TEST(PassBindingsCacheTest, setStencilReference) {
 }
 
 TEST(PassBindingsCacheTest, setScissor) {
-  auto context = CreateMockVulkanContext();
+  auto context = MockVulkanContextBuilder().Build();
   PassBindingsCache cache;
   auto encoder = std::make_unique<CommandEncoderFactoryVK>(context)->Create();
   auto buffer = encoder->GetCommandBuffer();
@@ -66,7 +66,7 @@ TEST(PassBindingsCacheTest, setScissor) {
 }
 
 TEST(PassBindingsCacheTest, setViewport) {
-  auto context = CreateMockVulkanContext();
+  auto context = MockVulkanContextBuilder().Build();
   PassBindingsCache cache;
   auto encoder = std::make_unique<CommandEncoderFactoryVK>(context)->Create();
   auto buffer = encoder->GetCommandBuffer();

engine/src/flutter/impeller/renderer/backend/vulkan/test/mock_vulkan.cc

@@ -3,8 +3,10 @@
 // found in the LICENSE file.
 
 #include "impeller/renderer/backend/vulkan/test/mock_vulkan.h"
+#include <cstring>
 #include <vector>
 #include "fml/macros.h"
+#include "fml/thread_local.h"
 #include "impeller/base/thread_safety.h"
 
 namespace impeller {
@@ -54,25 +56,41 @@ class MockDevice final {
 
 void noop() {}
 
+FML_THREAD_LOCAL std::vector<std::string> g_instance_extensions;
+
 VkResult vkEnumerateInstanceExtensionProperties(
     const char* pLayerName,
     uint32_t* pPropertyCount,
     VkExtensionProperties* pProperties) {
   if (!pProperties) {
-    *pPropertyCount = 2;
-
+    *pPropertyCount = g_instance_extensions.size();
   } else {
-    strcpy(pProperties[0].extensionName, "VK_KHR_surface");
-    pProperties[0].specVersion = 0;
-    strcpy(pProperties[1].extensionName, "VK_MVK_macos_surface");
-    pProperties[1].specVersion = 0;
+    uint32_t count = 0;
+    for (const std::string& ext : g_instance_extensions) {
+      strncpy(pProperties[count].extensionName, ext.c_str(),
+              sizeof(VkExtensionProperties::extensionName));
+      pProperties[count].specVersion = 0;
+      count++;
+    }
   }
   return VK_SUCCESS;
 }
 
+FML_THREAD_LOCAL std::vector<std::string> g_instance_layers;
+
 VkResult vkEnumerateInstanceLayerProperties(uint32_t* pPropertyCount,
                                             VkLayerProperties* pProperties) {
-  *pPropertyCount = 0;
+  if (!pProperties) {
+    *pPropertyCount = g_instance_layers.size();
+  } else {
+    uint32_t count = 0;
+    for (const std::string& layer : g_instance_layers) {
+      strncpy(pProperties[count].layerName, layer.c_str(),
+              sizeof(VkLayerProperties::layerName));
+      pProperties[count].specVersion = 0;
+      count++;
+    }
+  }
   return VK_SUCCESS;
 }
 
@@ -415,6 +433,20 @@ VkResult vkGetFenceStatus(VkDevice device, VkFence fence) {
   return VK_SUCCESS;
 }
 
+VkResult vkCreateDebugUtilsMessengerEXT(
+    VkInstance instance,
+    const VkDebugUtilsMessengerCreateInfoEXT* pCreateInfo,
+    const VkAllocationCallbacks* pAllocator,
+    VkDebugUtilsMessengerEXT* pMessenger) {
+  return VK_SUCCESS;
+}
+
+VkResult vkSetDebugUtilsObjectNameEXT(
+    VkDevice device,
+    const VkDebugUtilsObjectNameInfoEXT* pNameInfo) {
+  return VK_SUCCESS;
+}
+
 PFN_vkVoidFunction GetMockVulkanProcAddress(VkInstance instance,
                                             const char* pName) {
   if (strcmp("vkEnumerateInstanceExtensionProperties", pName) == 0) {
@@ -507,21 +539,30 @@ PFN_vkVoidFunction GetMockVulkanProcAddress(VkInstance instance,
     return (PFN_vkVoidFunction)vkWaitForFences;
   } else if (strcmp("vkGetFenceStatus", pName) == 0) {
     return (PFN_vkVoidFunction)vkGetFenceStatus;
+  } else if (strcmp("vkCreateDebugUtilsMessengerEXT", pName) == 0) {
+    return (PFN_vkVoidFunction)vkCreateDebugUtilsMessengerEXT;
+  } else if (strcmp("vkSetDebugUtilsObjectNameEXT", pName) == 0) {
+    return (PFN_vkVoidFunction)vkSetDebugUtilsObjectNameEXT;
   }
   return noop;
 }
 
 }  // namespace
 
-std::shared_ptr<ContextVK> CreateMockVulkanContext(
-    const std::function<void(ContextVK::Settings&)>& settings_callback) {
+MockVulkanContextBuilder::MockVulkanContextBuilder()
+    : instance_extensions_({"VK_KHR_surface", "VK_MVK_macos_surface"}) {}
+
+std::shared_ptr<ContextVK> MockVulkanContextBuilder::Build() {
   auto message_loop = fml::ConcurrentMessageLoop::Create();
   ContextVK::Settings settings;
   settings.proc_address_callback = GetMockVulkanProcAddress;
-  if (settings_callback) {
-    settings_callback(settings);
+  if (settings_callback_) {
+    settings_callback_(settings);
   }
-  return ContextVK::Create(std::move(settings));
+  g_instance_extensions = instance_extensions_;
+  g_instance_layers = instance_layers_;
+  std::shared_ptr<ContextVK> result = ContextVK::Create(std::move(settings));
+  return result;
 }
 
 std::shared_ptr<std::vector<std::string>> GetMockVulkanFunctions(

engine/src/flutter/impeller/renderer/backend/vulkan/test/mock_vulkan.h

@@ -16,18 +16,44 @@ namespace testing {
 std::shared_ptr<std::vector<std::string>> GetMockVulkanFunctions(
     VkDevice device);
 
-//------------------------------------------------------------------------------
-/// @brief      Create a Vulkan context with Vulkan functions mocked. The caller
-///             is given a chance to tinker on the settings right before a
-///             context is created.
-///
-/// @param[in]  settings_callback  The settings callback
-///
-/// @return     A context if one can be created.
-///
-std::shared_ptr<ContextVK> CreateMockVulkanContext(
-    const std::function<void(ContextVK::Settings&)>& settings_callback =
-        nullptr);
+class MockVulkanContextBuilder {
+ public:
+  MockVulkanContextBuilder();
+
+  //------------------------------------------------------------------------------
+  /// @brief      Create a Vulkan context with Vulkan functions mocked. The
+  ///             caller is given a chance to tinker on the settings right
+  ///             before a context is created.
+  ///
+  /// @return     A context if one can be created.
+  ///
+  std::shared_ptr<ContextVK> Build();
+
+  /// A callback that allows the modification of the ContextVK::Settings before
+  /// the context is made.
+  MockVulkanContextBuilder& SetSettingsCallback(
+      const std::function<void(ContextVK::Settings&)>& settings_callback) {
+    settings_callback_ = settings_callback;
+    return *this;
+  }
+
+  MockVulkanContextBuilder& SetInstanceExtensions(
+      const std::vector<std::string>& instance_extensions) {
+    instance_extensions_ = instance_extensions;
+    return *this;
+  }
+
+  MockVulkanContextBuilder& SetInstanceLayers(
+      const std::vector<std::string>& instance_layers) {
+    instance_layers_ = instance_layers;
+    return *this;
+  }
+
+ private:
+  std::function<void(ContextVK::Settings&)> settings_callback_;
+  std::vector<std::string> instance_extensions_;
+  std::vector<std::string> instance_layers_;
+};
 
 }  // namespace testing
 }  // namespace impeller

engine/src/flutter/impeller/renderer/backend/vulkan/test/mock_vulkan_unittests.cc

@@ -14,7 +14,7 @@ TEST(MockVulkanContextTest, IsThreadSafe) {
   // In a typical app, there is a single ContextVK per app, shared b/w threads.
   //
   // This test ensures that the (mock) ContextVK is thread-safe.
-  auto const context = CreateMockVulkanContext();
+  auto const context = MockVulkanContextBuilder().Build();
 
   // Spawn two threads, and have them create a CommandPoolVK each.
   std::thread thread1([&context]() {