switch to C++17

NEWS

@@ -12,6 +12,8 @@ ver 0.22 (not yet released)
   - ffmpeg: new plugin based on FFmpeg's libavfilter library
   - hdcd: new plugin based on FFmpeg's "af_hdcd" for HDCD playback
   - volume: convert S16 to S24 to preserve quality and reduce dithering noise
+* switch to C++17
+  - GCC 7 or clang 4 (or newer) recommended
 
 ver 0.21.12 (2019/08/03)
 * decoder

doc/developer.rst

@@ -12,7 +12,7 @@ Code Style
 * indent with tabs (width 8)
 * don't write CPP when you can write C++: use inline functions and constexpr instead of macros
 * comment your code, document your APIs
-* the code should be C++14 compliant, and must compile with :program:`GCC` 6.0 and :program:`clang` 3.4
+* the code should be C++17 compliant, and must compile with :program:`GCC` 7 and :program:`clang` 4
 * report error conditions with C++ exceptions, preferable derived from :envvar:`std::runtime_error`
 * all code must be exception-safe
 * classes and functions names use CamelCase; variables are lower-case with words separated by underscore

meson.build

@@ -5,7 +5,7 @@ project(
   meson_version: '>= 0.49.0',
   default_options: [
     'c_std=c99',
-    'cpp_std=c++14'
+    'cpp_std=c++17'
   ],
   license: 'GPLv2+',
 )
@@ -15,10 +15,10 @@ version_cxx = vcs_tag(input: 'src/GitVersion.cxx', output: 'GitVersion.cxx')
 compiler = meson.get_compiler('cpp')
 c_compiler = meson.get_compiler('c')
 
-if compiler.get_id() == 'gcc' and compiler.version().version_compare('<6')
-  warning('Your GCC version is too old.  You need at least version 6.')
-elif compiler.get_id() == 'clang' and compiler.version().version_compare('<3')
-  warning('Your clang version is too old.  You need at least version 3.')
+if compiler.get_id() == 'gcc' and compiler.version().version_compare('<7')
+  warning('Your GCC version is too old.  You need at least version 7.')
+elif compiler.get_id() == 'clang' and compiler.version().version_compare('<4')
+  warning('Your clang version is too old.  You need at least version 4.')
 endif
 
 conf = configuration_data()

src/event/MaskMonitor.hxx

@@ -34,7 +34,7 @@
 class MaskMonitor final {
 	DeferEvent defer;
 
-	typedef BoundMethod<void(unsigned)> Callback;
+	typedef BoundMethod<void(unsigned) noexcept> Callback;
 	const Callback callback;
 
 	std::atomic_uint pending_mask;

src/event/TimerEvent.hxx

@@ -44,7 +44,7 @@ class TimerEvent final {
 
 	EventLoop &loop;
 
-	typedef BoundMethod<void()> Callback;
+	typedef BoundMethod<void() noexcept> Callback;
 	const Callback callback;
 
 	/**

src/lib/dbus/AsyncRequest.hxx

@@ -49,7 +49,7 @@ namespace ODBus {
 class AsyncRequest {
 	PendingCall pending_call;
 
-	std::function<void(Message) noexcept> callback;
+	std::function<void(Message)> callback;
 
 public:
 	operator bool() const noexcept {

src/thread/Thread.hxx

@@ -32,7 +32,7 @@
 #include <assert.h>
 
 class Thread {
-	typedef BoundMethod<void()> Function;
+	typedef BoundMethod<void() noexcept> Function;
 	const Function f;
 
 #ifdef _WIN32

src/util/BindMethod.hxx

 /*
- * Copyright (C) 2016 Max Kellermann <max.kellermann@gmail.com>
+ * Copyright 2016-2018 Max Kellermann <max.kellermann@gmail.com>
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -30,6 +30,8 @@
 #ifndef BIND_METHOD_HXX
 #define BIND_METHOD_HXX
 
+#include "Compiler.h"
+
 #include <type_traits>
 #include <utility>
 
@@ -43,9 +45,21 @@
 template<typename S=void()>
 class BoundMethod;
 
-template<typename R, typename... Args>
-class BoundMethod<R(Args...)> {
-	typedef R (*function_pointer)(void *instance, Args... args);
+#if GCC_OLDER_THAN(7,0)
+static constexpr bool NoExcept = false;
+#endif
+
+template<typename R,
+#if !GCC_OLDER_THAN(7,0)
+	bool NoExcept,
+#endif
+	typename... Args>
+class BoundMethod<R(Args...) noexcept(NoExcept)> {
+	typedef R (*function_pointer)(void *instance, Args... args)
+#if !GCC_OLDER_THAN(7,0)
+		noexcept(NoExcept)
+#endif
+		;
 
 	void *instance_;
 	function_pointer function;
@@ -91,9 +105,21 @@ namespace BindMethodDetail {
 template<typename T, typename S>
 struct MethodWithSignature;
 
-template<typename T, typename R, typename... Args>
-struct MethodWithSignature<T, R(Args...)> {
-	typedef R (T::*method_pointer)(Args...);
+template<typename T,
+#if !GCC_OLDER_THAN(7,0)
+	 bool NoExcept,
+#endif
+	 typename R, typename... Args>
+struct MethodWithSignature<T, R(Args...)
+#if !GCC_OLDER_THAN(7,0)
+			   noexcept(NoExcept)
+#endif
+			   > {
+	typedef R (T::*method_pointer)(Args...)
+#if !GCC_OLDER_THAN(7,0)
+		noexcept(NoExcept)
+#endif
+		;
 };
 
 /**
@@ -104,8 +130,12 @@ struct MethodWithSignature<T, R(Args...)> {
 template<typename M>
 struct MethodSignatureHelper;
 
-template<typename R, typename T, typename... Args>
-struct MethodSignatureHelper<R (T::*)(Args...)> {
+template<typename R,
+#if !GCC_OLDER_THAN(7,0)
+	 bool NoExcept,
+#endif
+	 typename T, typename... Args>
+struct MethodSignatureHelper<R (T::*)(Args...) noexcept(NoExcept)> {
 	/**
 	 * The class which contains the given method (signature).
 	 */
@@ -115,7 +145,11 @@ struct MethodSignatureHelper<R (T::*)(Args...)> {
 	 * A function type which describes the "plain" function
 	 * signature.
 	 */
-	typedef R plain_signature(Args...);
+	typedef R plain_signature(Args...)
+#if !GCC_OLDER_THAN(7,0)
+		noexcept(NoExcept)
+#endif
+		;
 };
 
 /**
@@ -125,9 +159,17 @@ struct MethodSignatureHelper<R (T::*)(Args...)> {
 template<typename S>
 struct MethodWrapperWithSignature;
 
-template<typename R, typename... Args>
-struct MethodWrapperWithSignature<R(Args...)> {
-	typedef R (*function_pointer)(void *instance, Args...);
+template<typename R,
+#if !GCC_OLDER_THAN(7,0)
+	 bool NoExcept,
+#endif
+	 typename... Args>
+struct MethodWrapperWithSignature<R(Args...) noexcept(NoExcept)> {
+	typedef R (*function_pointer)(void *instance, Args...)
+#if !GCC_OLDER_THAN(7,0)
+		noexcept(NoExcept)
+#endif
+		;
 };
 
 /**
@@ -140,9 +182,9 @@ struct MethodWrapperWithSignature<R(Args...)> {
  * @param R the return type
  * @param Args the method arguments
  */
-template<typename T, typename M, M method, typename R, typename... Args>
+template<typename T, bool NoExcept, typename M, M method, typename R, typename... Args>
 struct BindMethodWrapperGenerator2 {
-	static R Invoke(void *_instance, Args... args) {
+	static R Invoke(void *_instance, Args... args) noexcept(NoExcept) {
 		auto &t = *(T *)_instance;
 		return (t.*method)(std::forward<Args>(args)...);
 	}
@@ -159,9 +201,13 @@ struct BindMethodWrapperGenerator2 {
 template<typename T, typename M, M method, typename S>
 struct BindMethodWrapperGenerator;
 
-template<typename T, typename M, M method, typename R, typename... Args>
-struct BindMethodWrapperGenerator<T, M, method, R(Args...)>
-	: BindMethodWrapperGenerator2<T, M, method, R, Args...> {
+template<typename T,
+#if !GCC_OLDER_THAN(7,0)
+	 bool NoExcept,
+#endif
+	 typename M, M method, typename R, typename... Args>
+struct BindMethodWrapperGenerator<T, M, method, R(Args...) noexcept(NoExcept)>
+	: BindMethodWrapperGenerator2<T, NoExcept, M, method, R, Args...> {
 };
 
 template<typename T, typename S,
@@ -180,19 +226,31 @@ MakeBindMethodWrapper() noexcept
 template<typename S>
 struct FunctionTraits;
 
-template<typename R, typename... Args>
-struct FunctionTraits<R(Args...)> {
+template<typename R,
+#if !GCC_OLDER_THAN(7,0)
+	 bool NoExcept,
+#endif
+	 typename... Args>
+struct FunctionTraits<R(Args...) noexcept(NoExcept)> {
 	/**
 	 * A function type which describes the "plain" function
 	 * signature.
 	 */
-	typedef R function_type(Args...);
+	typedef R function_type(Args...)
+#if !GCC_OLDER_THAN(7,0)
+		noexcept(NoExcept)
+#endif
+		;
 
 	/**
 	 * A function pointer type which describes the "plain"
 	 * function signature.
 	 */
-	typedef R (*pointer_type)(Args...);
+	typedef R (*pointer_type)(Args...)
+#if !GCC_OLDER_THAN(7,0)
+		noexcept(NoExcept)
+#endif
+		;
 };
 
 /**
@@ -205,9 +263,9 @@ struct FunctionTraits<R(Args...)> {
  * @param R the return type
  * @param Args the function arguments
  */
-template<typename F, F function, typename R, typename... Args>
+template<bool NoExcept, typename F, F function, typename R, typename... Args>
 struct BindFunctionWrapperGenerator2 {
-	static R Invoke(void *, Args... args) {
+	static R Invoke(void *, Args... args) noexcept(NoExcept) {
 		return function(std::forward<Args>(args)...);
 	}
 };
@@ -222,9 +280,13 @@ struct BindFunctionWrapperGenerator2 {
 template<typename S, typename P, P function>
 struct BindFunctionWrapperGenerator;
 
-template<typename P, P function, typename R, typename... Args>
-struct BindFunctionWrapperGenerator<R(Args...), P, function>
-	: BindFunctionWrapperGenerator2<P, function, R, Args...> {
+template<typename P, P function,
+#if !GCC_OLDER_THAN(7,0)
+	 bool NoExcept,
+#endif
+	 typename R, typename... Args>
+struct BindFunctionWrapperGenerator<R(Args...) noexcept(NoExcept), P, function>
+	: BindFunctionWrapperGenerator2<NoExcept, P, function, R, Args...> {
 };
 
 template<typename T, typename T::pointer_type function>

test/meson.build

@@ -49,6 +49,8 @@ test('TestUtil', executable(
 test('TestRewindInputStream', executable(
   'TestRewindInputStream',
   'TestRewindInputStream.cxx',
+  '../src/Log.cxx',
+  '../src/LogBackend.cxx',
   include_directories: inc,
   dependencies: [
     input_glue_dep,