Deprecate LazyInstance
It will no longer compile in C++20. Use the NoDestructor approach
introduced by chromium instead.
See: https://github.com/microsoft/STL/issues/661 for an extended
discussion of why this was changed.
Change-Id: Ie1a658058dc73c5e2488d2613005a323b5c8bbcb
GitOrigin-RevId: 28964186e78366fc13a8028bb348a42af1c1a12d
diff --git a/.gitignore b/.gitignore
index 4a3faac..4bf2b0c 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,4 @@
+.cache
.vscode
/build*/
/install*/
diff --git a/base/BUILD.bazel b/base/BUILD.bazel
index d199fed..fb16bc9 100644
--- a/base/BUILD.bazel
+++ b/base/BUILD.bazel
@@ -13,7 +13,10 @@
}),
includes = ["include"],
visibility = ["//visibility:public"],
- deps = ["//hardware/google/aemu/host-common:aemu-host-common-headers"],
+ deps = [
+ "//hardware/google/aemu/host-common:aemu-host-common-headers",
+ "@com_google_absl//absl/strings:str_format",
+ ],
)
cc_library(
@@ -35,7 +38,12 @@
srcs = [
"system-native-mac.mm",
],
+ sdk_frameworks = [
+ "IOkit",
+ "AppKit",
+ ],
deps = [":aemu-base-headers"],
+ alwayslink = True,
)
cc_library(
@@ -96,6 +104,11 @@
"@platforms//os:windows": [
"-DEFAULTLIB:Shlwapi.lib",
],
+ "@platforms//os:macos": [
+ "-framework Foundation",
+ "-framework AppKit",
+ "-framework IOKit",
+ ],
"//conditions:default": [],
}),
visibility = ["//visibility:public"],
@@ -103,6 +116,7 @@
":aemu-base-headers",
":aemu-base-metrics",
"//external/lz4",
+ "//hardware/google/aemu/host-common:logging",
] + select({
"@platforms//os:macos": [
":aemu-base-darwin",
@@ -121,6 +135,7 @@
"LayoutResolver_unittest.cpp",
"LruCache_unittest.cpp",
"ManagedDescriptor_unittest.cpp",
+ "NoDestructor_unittest.cpp",
"Optional_unittest.cpp",
"StringFormat_unittest.cpp",
"SubAllocator_unittest.cpp",
@@ -135,7 +150,12 @@
deps = [
":aemu-base",
":aemu-base-headers",
+ "//hardware/google/aemu/base:aemu-base-darwin",
+ "//hardware/google/aemu/base:aemu-base-metrics",
"//hardware/google/aemu/host-common:logging",
+ "@com_google_absl//absl/log",
+ "@com_google_absl//absl/strings",
+ "@com_google_absl//absl/strings:str_format",
"@com_google_googletest//:gtest_main",
],
)
diff --git a/base/NoDestructor_unittest.cpp b/base/NoDestructor_unittest.cpp
new file mode 100644
index 0000000..ee563ce
--- /dev/null
+++ b/base/NoDestructor_unittest.cpp
@@ -0,0 +1,48 @@
+// Copyright 2018 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+#include "aemu/base/memory/NoDestructor.h"
+#include <string>
+#include <utility>
+#include <gtest/gtest.h>
+#include "aemu/base/Log.h"
+
+namespace android::base {
+namespace {
+struct CheckOnDestroy {
+ ~CheckOnDestroy() { dfatal("Destructor was called"); }
+};
+TEST(NoDestructorTest, SkipsDestructors) {
+ NoDestructor<CheckOnDestroy> destructor_should_not_run;
+}
+struct CopyOnly {
+ CopyOnly() = default;
+ CopyOnly(const CopyOnly&) = default;
+ CopyOnly& operator=(const CopyOnly&) = default;
+ CopyOnly(CopyOnly&&) = delete;
+ CopyOnly& operator=(CopyOnly&&) = delete;
+};
+struct MoveOnly {
+ MoveOnly() = default;
+ MoveOnly(const MoveOnly&) = delete;
+ MoveOnly& operator=(const MoveOnly&) = delete;
+ MoveOnly(MoveOnly&&) = default;
+ MoveOnly& operator=(MoveOnly&&) = default;
+};
+struct ForwardingTestStruct {
+ ForwardingTestStruct(const CopyOnly&, MoveOnly&&) {}
+};
+TEST(NoDestructorTest, ForwardsArguments) {
+ CopyOnly copy_only;
+ MoveOnly move_only;
+ static NoDestructor<ForwardingTestStruct> test_forwarding(
+ copy_only, std::move(move_only));
+}
+TEST(NoDestructorTest, Accessors) {
+ static NoDestructor<std::string> awesome("awesome");
+ EXPECT_EQ("awesome", *awesome);
+ EXPECT_EQ(0, awesome->compare("awesome"));
+ EXPECT_EQ(0, awesome.get()->compare("awesome"));
+}
+} // namespace
+} // namespace base
\ No newline at end of file
diff --git a/base/include/aemu/base/memory/LazyInstance.h b/base/include/aemu/base/memory/LazyInstance.h
index c859e17..c50baff 100644
--- a/base/include/aemu/base/memory/LazyInstance.h
+++ b/base/include/aemu/base/memory/LazyInstance.h
@@ -94,6 +94,20 @@
// Atomic state variable type. Used to ensure to synchronize concurrent
// initialization and access without incurring the full cost of a mutex
// lock/unlock.
+
+// !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! DEPRECATED !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
+// Please don't use this macro. Use a function-local static of type
+// android::base::NoDestructor<T> instead:
+//
+// Factory& Factory::GetInstance() {
+// static base::NoDestructor<Factory> instance;
+// return *instance;
+// }
+//
+// From C++20 onwards this will no longer compile. See:
+// See https://github.com/microsoft/STL/issues/661
+// For details on issues and guarantees around atomic initialization.
+// !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
struct LazyInstanceState {
enum class State : char {
Init = 0,
@@ -180,7 +194,7 @@
static_assert(std::is_standard_layout<LazyInstance>::value,
"LazyInstance<T> is not a standard layout type");
#ifndef _MSC_VER
- // These checks are not working in vs2019..
+ // These checks are not working in vs2019..
static_assert(
internal::is_trivially_default_constructible<LazyInstance>::value,
"LazyInstance<T> can't be trivially default constructed");
diff --git a/base/include/aemu/base/memory/NoDestructor.h b/base/include/aemu/base/memory/NoDestructor.h
new file mode 100644
index 0000000..3219b6f
--- /dev/null
+++ b/base/include/aemu/base/memory/NoDestructor.h
@@ -0,0 +1,60 @@
+// Copyright 2018 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+#pragma once
+#include <utility>
+namespace android::base {
+// A wrapper that makes it easy to create an object of type T with static
+// storage duration that:
+// - is only constructed on first access
+// - never invokes the destructor
+// in order to satisfy the styleguide ban on global constructors and
+// destructors.
+//
+// Runtime constant example:
+// const std::string& GetLineSeparator() {
+// // Forwards to std::string(size_t, char, const Allocator&) constructor.
+// static const base::NoDestructor<std::string> s(5, '-');
+// return s;
+// }
+//
+// More complex initialization with a lambda:
+// const std::string& GetSessionNonce() {
+// static const base::NoDestructor<std::string> nonce([] {
+// std::string s(16);
+// crypto::RandString(s.data(), s.size());
+// return s;
+// })());
+// return *nonce;
+// }
+//
+// NoDestructor<T> stores the object inline, so it also avoids a pointer
+// indirection and a malloc. Code should prefer to use NoDestructor<T> over:
+// - The CR_DEFINE_STATIC_LOCAL() helper macro.
+// - A function scoped static T* or T& that is dynamically initialized.
+// - A global base::LazyInstance<T>.
+//
+// Note that since the destructor is never run, this *will* leak memory if used
+// as a stack or member variable. Furthermore, a NoDestructor<T> should never
+// have global scope as that may require a static initializer.
+template <typename T>
+class NoDestructor {
+ public:
+ // Not constexpr; just write static constexpr T x = ...; if the value should
+ // be a constexpr.
+ template <typename... Args>
+ explicit NoDestructor(Args&&... args) {
+ new (get()) T(std::forward<Args>(args)...);
+ }
+ ~NoDestructor() = default;
+ const T& operator*() const { return *get(); }
+ T& operator*() { return *get(); }
+ const T* operator->() const { return get(); }
+ T* operator->() { return get(); }
+ const T* get() const { return reinterpret_cast<const T*>(&storage_); }
+ T* get() { return reinterpret_cast<T*>(&storage_); }
+
+ private:
+ alignas(T) char storage_[sizeof(T)];
+};
+} // namespace android::base
diff --git a/host-common/BUILD.bazel b/host-common/BUILD.bazel
index 0be01e0..08cc1a4 100644
--- a/host-common/BUILD.bazel
+++ b/host-common/BUILD.bazel
@@ -106,40 +106,16 @@
)
# Testing Libraries and Executable (conditional)
-cc_library(
- name = "aemu-host-common-testing-support",
- srcs = [
- "testing/HostAddressSpace.cpp",
- "testing/MockAndroidEmulatorWindowAgent.cpp",
- "testing/MockAndroidMultiDisplayAgent.cpp",
- "testing/MockAndroidVmOperations.cpp",
- "testing/MockGraphicsAgentFactory.cpp",
- ],
- deps = [
- ":aemu-host-common-headers",
- "//hardware/google/aemu/base:aemu-base-headers",
- "@com_google_gmock//:gmock",
- "@com_google_googletest//:gtest",
- ],
-)
-
cc_test(
name = "aemu-host-common_unittests",
- srcs = [
- "GfxstreamFatalError_unittest.cpp",
- "HostAddressSpace_unittest.cpp",
- "HostmemIdMapping_unittest.cpp",
- "address_space_graphics_unittests.cpp",
- "address_space_host_memory_allocator_unittests.cpp",
- "address_space_shared_slots_host_memory_allocator_unittests.cpp",
- "logging_unittest.cpp",
- ],
+ srcs = glob([
+ "*_unitests.cpp",
+ "testing/**",
+ ]),
+ includes = ["testing"],
deps = [
":aemu-host-common-headers",
- ":aemu-host-common-testing-support",
- ":gfxstream_host_common",
":logging",
- "//common:gfxstream_base",
"//hardware/google/aemu/base:aemu-base-headers",
"@com_google_googletest//:gtest_main",
],
