Merge "libbinder: fix ToString() for smart pointers" (616ddc4f) · Commits · e / os / android_frameworks_native

libs/binder/ndk/include_cpp/android/binder_to_string.h

+37 −11

Original line number	Diff line number	Diff line
		@@ -28,10 +28,22 @@

		#include <codecvt>
		#include <locale>
		#include <memory>
		#include <optional>
		#include <sstream>
		#include <string>
		#include <type_traits>

		#if __has_include(<utils/StrongPointer.h>)
		#include <utils/StrongPointer.h>
		#define HAS_STRONG_POINTER
		#endif

		#if __has_include(<utils/String16.h>)
		#include <utils/String16.h>
		#define HAS_STRING16
		#endif

		#if __has_include(<android/binder_ibinder.h>)
		#include <android/binder_auto_utils.h>
		#include <android/binder_interface_utils.h>
		@@ -42,9 +54,6 @@
		#include <binder/IInterface.h>
		#include <binder/ParcelFileDescriptor.h>
		#include <binder/ParcelableHolder.h>
		#include <utils/String16.h>
		#include <utils/StrongPointer.h>
		#define HAS_CPP_INTERFACE
		#endif //_has_include

		namespace android {
		@@ -80,11 +89,28 @@ class HasToStringFunction {
		enum { value = decltype(_test<_T>(0))::value };
		};

		// Truthy if _T is like a pointer
		template <typename T, template <typename...> typename U>
		struct IsInstantiationOf : std::false_type {};

		template <template <typename...> typename U, typename... Args>
		struct IsInstantiationOf<U<Args...>, U> : std::true_type {};

		// Truthy if _T is like a pointer: one of sp/optional/shared_ptr
		template <typename _T>
		class IsPointerLike {
		template <typename _U>
		static auto _test(int) -> decltype(!std::declval<_U>(), *std::declval<_U>(), std::true_type());
		static std::enable_if_t<
		#ifdef HAS_STRONG_POINTER
		IsInstantiationOf<_U, sp>::value \|\| // for IBinder and interface types in the C++
		// backend
		#endif
		IsInstantiationOf<_U, std::optional>::value \|\| // for @nullable types in the
		// C++/NDK backends
		IsInstantiationOf<_U, std::shared_ptr>::value, // for interface types in the
		// NDK backends

		std::true_type>
		_test(int);
		template <typename _U>
		static std::false_type _test(...);

		@@ -142,12 +168,17 @@ std::string ToString(const _T& t) {
		return std::to_string(t);
		} else if constexpr (std::is_same_v<std::string, _T>) {
		return t;
		#ifdef HAS_CPP_INTERFACE
		#ifdef HAS_STRING16
		} else if constexpr (std::is_same_v<String16, _T>) {
		std::stringstream out;
		out << t;
		return out.str();
		#endif
		} else if constexpr (details::IsPointerLike<_T>::value) {
		if (!t) return "(null)";
		std::stringstream out;
		out << ToString(*t);
		return out.str();
		} else if constexpr (details::HasToStringMethod<_T>::value) {
		return t.toString();
		} else if constexpr (details::HasToStringFunction<_T>::value) {
		@@ -168,11 +199,6 @@ std::string ToString(const _T& t) {
		}
		out << "]";
		return out.str();
		} else if constexpr (details::IsPointerLike<_T>::value) {
		if (!t) return "(null)";
		std::stringstream out;
		out << ToString(*t);
		return out.str();
		} else {
		return "{no toString() implemented}";
		}