Modernize thread code.

CMakeLists.txt

@@ -13,6 +13,7 @@ add_library( alepha SHARED
 	ProgramOptions.cc
 	string_algorithms.cc
 	word_wrap.cc
+	Thread.cc
 )
 # Everything else depends upon it
 link_libraries( alepha )

Thread.cc

@@ -0,0 +1,130 @@
+static_assert( __cplusplus > 2020'99 );
+
+#include "Thread.h"
+
+#include <stop_token>
+#include <condition_variable>
+
+#include <Alepha/Utility/StaticValue.h>
+#include <Alepha/Utility/evaluation_helpers.h>
+
+namespace Alepha::Hydrogen::detail::Thread_m
+{
+	namespace
+	{
+		struct ThreadState
+		{
+			std::mutex access;
+			std::stop_source source;
+			std::exception_ptr notification;
+
+			void
+			deliver( std::exception_ptr ptr )
+			{
+				std::lock_guard lock{ access };
+				if( notification ) return; // TODO: Don't swallow blocked interrupts?
+				notification= std::move( ptr );
+				source.request_stop();
+			}
+
+			void
+			interruption_point( std::lock_guard< std::mutex > & )
+			{
+				if( notification == nullptr ) return;
+				source= std::stop_source{};
+				auto next= std::move( notification );
+				notification= nullptr;
+				std::rethrow_exception( next );
+			}
+
+			void
+			interruption_point()
+			{
+				std::lock_guard lock( access );
+				interruption_point( lock );
+			}
+
+			std::stop_token
+			getToken()
+			{
+				std::lock_guard lock( access );
+				interruption_point( lock );
+				return source.get_token();
+			}
+		};
+
+		thread_local Utility::StaticValue< std::shared_ptr< ThreadState > > state;
+	}
+
+	struct ConditionVariable::Impl
+	{
+		std::condition_variable_any cond;
+	};
+
+	ConditionVariable::~ConditionVariable()= default;
+
+	ConditionVariable::ConditionVariable()
+		: pimpl( std::make_unique< Impl >() ) {}
+
+	void
+	ConditionVariable::notify_one()
+	{
+		impl().cond.notify_one();
+	}
+
+	void
+	ConditionVariable::notify_all()
+	{
+		impl().cond.notify_all();
+	}
+
+	void
+	ConditionVariable::wait( unique_lock< mutex > &lock )
+	{
+		auto stop= Utility::evaluate <=[]
+		{
+			std::lock_guard lock( state()->access );
+			return state()->source.get_token();
+		};
+		impl().cond.wait( lock, stop, [val= std::uint64_t()] mutable { return val++; } );
+		state()->interruption_point();
+	}
+
+	struct Thread::Impl
+	{
+		std::thread thr;
+		std::weak_ptr< ThreadState > state;
+	};
+
+	Thread::~Thread()= default;
+
+	Thread::Thread( std::function< void () > start )
+	{
+		auto newState= std::make_shared< ThreadState >();
+		std::weak_ptr local= newState;
+
+		auto entry= [newState= std::move( newState ), start= std::move( start )]
+		{
+			state()= std::move( newState );
+			start();
+		};
+
+		pimpl= std::make_unique< Impl >( std::thread{ std::move( entry ) }, std::move( local ) );
+	}
+
+	void
+	Thread::join()
+	{
+		// TODO: Make interruptible.
+		impl().thr.join();
+	}
+
+	void
+	Thread::notify( std::exception_ptr p )
+	{
+		const auto state= impl().state.lock();
+		if( not state ) return;
+
+		state->deliver( std::move( p ) );
+	}
+}

Thread.h

@@ -4,165 +4,94 @@ static_assert( __cplusplus > 2020'99 );
 
 #include <Alepha/Alepha.h>
 
-#include <boost/thread.hpp>
+#include <mutex>
-#include <boost/thread/mutex.hpp>
+#include <stop_token>
-#include <boost/thread/condition_variable.hpp>
+#include <functional>
+#include <exception>
 
 #include <Alepha/Exception.h>
 
-namespace Alepha::Hydrogen
+namespace Alepha::Hydrogen  ::detail::  Thread_m
 {
-	namespace detail::Thread_m
+	inline namespace exports
-	{
-		inline namespace exports {}
-		namespace exports
 	{
 		using CrossThreadNotificationRethrowError= synthetic_exception< struct cross_thread_notification_failure, Error >;
-		}
-
-		class NotificationInfo
-		{
-			private:
-				std::mutex access;
-				std::exception_ptr notification;
-
-			public:
-				//template( Concepts::DerivedFrom< Notification > Exc )
-				void
-				setNotification( std::exception_ptr &&exception )
-				{
-					std::lock_guard lock( access );
-					notification= std::move( exception );
-				}
-
-				template< typename Callable >
-				void
-				check_interrupt( Callable &&callable )
-				try
-				{
-					callable();
-				}
-				catch( const boost::thread_interrupted & )
-				{
-					std::lock_guard lock( access );
-					if( not notification ) throw;
-					try
-					{
-						std::rethrow_exception( std::move( notification ) );
-					}
-					catch( const std::bad_alloc & )
-					{
-						throw build_exception< CrossThreadNotificationRethrowError >( "`std::bad_alloc` encountered in trying to "
-								"raise a cross-thread notification" );
-					}
-				}
-		};
-			
-		inline thread_local NotificationInfo notification;
-
-		namespace exports
-		{
-			class ConditionVariable
-				: private boost::condition_variable
-			{
-				public:
-					using condition_variable::notify_all;
-					using condition_variable::notify_one;
-
-					template< typename Lock >
-					void
-					wait( Lock &&lock )
-					{
-						notification.check_interrupt( [&]{ condition_variable::wait( std::forward< Lock >( lock ) ); } );
-					}
-
-					template< typename Lock, typename Predicate >
-					void
-					wait( Lock &&lock, Predicate &&predicate )
-					{
-						notification.check_interrupt( [&]{ condition_variable::wait( std::forward< Lock >( lock ),
-								std::forward< Predicate >( predicate ) ); } );
-					}
-			};
-
 		namespace this_thread
 		{
-				template< typename Clock, typename Duration >
+			//void sleep( std::chrono::duration );
-				void
-				sleep_until( const boost::chrono::time_point< Clock, Duration > &abs_time )
-				{
-					notification.check_interrupt( [&]{ boost::this_thread::sleep_until( abs_time ); } );
 		}
 
-#if 0
+		struct ThreadInterrupted;
-				template< typename Rep, typename Period >
+		class Thread;
-				void
+		using thread= Thread;
-				sleep_for( const boost::chrono::duration< Rep, Period > &rel_time )
+		class ConditionVariable;
-				{
+		using condition_variable= ConditionVariable;
-					notification.check_interrupt( [&]( boost::this_thread::sleep_until( rel_time ); } );
+
-				}
+		using std::mutex;
-#endif
+		using std::lock_guard;
-			}
+		using std::unique_lock;
 	}
 
-		struct ThreadNotification
+	class exports::ConditionVariable
 	{
-			NotificationInfo *myNotification= nullptr;
+		private:
-		};
+			struct Impl;
+			std::unique_ptr< Impl > pimpl;
+
+			auto &impl() { return *pimpl; }
+			const auto &impl() const { return *pimpl; }
 
-		namespace exports
-		{
-			class Thread
-				: ThreadNotification, boost::thread
-			{
 		public:
-					template< typename Callable >
+			~ConditionVariable();
-					explicit
+			ConditionVariable();
-					Thread( Callable &&callable )
-						: thread
-						(
-							[this, callable= std::forward< Callable >( callable )]
-							{
-								myNotification= &notification;
-								try { callable(); }
-								catch( const Notification & )
-								{
-									// Notifications are not fatal.
-								}
-							}
-						)
-					{}
 
-					using thread::join;
+			void wait( unique_lock< mutex > & );
-					using thread::detach;
 
-					using thread::interrupt;
-
-					//template( Concepts::DerivedFrom< Notification > Exc )
-					template< typename Exc >
 			void
-					interrupt( Exc &&exception )
+			wait( unique_lock< mutex > &lock, auto predicate )
-					try
 			{
-						throw std::forward< Exc >( exception );
+				while( not predicate() ) wait( lock );
-					}
-					catch( const Notification & )
-					{
-						myNotification->setNotification( std::current_exception() );
-						interrupt();
 			}
+
+			void notify_one();
+			void notify_all();
 	};
 
-			using Mutex= boost::mutex;
+	struct exports::ThreadInterrupted {};
-			using boost::mutex;
+
-			using boost::unique_lock;
+	class exports::Thread
-			using boost::lock_guard;
+	{
-		}
+		private:
+			struct Impl;
+			std::unique_ptr< Impl > pimpl;
+
+			auto &impl() { return *pimpl; }
+			const auto &impl() const { return *pimpl; }
+
+			void notify( std::exception_ptr );
+
+		public:
+			~Thread();
+			explicit Thread( std::function< void () > start );
+
+			template< typename Notification >
+			void
+			notify( Notification notification )
+			{
+				notify( std::make_exception_ptr( std::move( notification ) ) );
 			}
 
-	inline namespace exports {}
+			void
-	namespace exports::inline Thread_m
+			interrupt()
 			{
-		using namespace detail::Thread_m::exports;
+				notify( std::make_exception_ptr( ThreadInterrupted{} ) );
 			}
+
+			void join();
+	};
+}
+
+namespace Alepha::Hydrogen::inline exports::inline Thread_m
+{
+	using namespace detail::Thread_m::exports;
 }

Thread.test/thread.cc

@@ -23,8 +23,8 @@ namespace
 		"smoke"_test <=[] () -> bool
 		{
 			std::cerr << "Smoke started..." << std::endl;
-			Alepha::Mutex access;
+			Alepha::mutex access;
-			Alepha::ConditionVariable cv;
+			Alepha::condition_variable cv;
 			auto threadMain= [&]
 			{
 				try
@@ -34,7 +34,7 @@ namespace
 					cv.wait( lock );
 					std::cerr << "Child thread awoken illegally!" << std::endl;
 				}
-				catch( const boost::thread_interrupted & )
+				catch( const Alepha::ThreadInterrupted & )
 				{
 					std::cerr << "OOPS!  We didn't get intercepted!" << std::endl;
 					throw;
@@ -42,7 +42,6 @@ namespace
 				catch( const MyNotification &n )
 				{
 					std::cerr << "I caught it: " << n.message() << "!" << std::endl;
-					throw;
 				}
 			};
 
@@ -52,7 +51,7 @@ namespace
 			std::cerr << "Child thread now launched..." << std::endl;
 			::sleep( 1 );
 			access.unlock();
-			thr.interrupt( Alepha::build_exception< MyNotification >( "My message" ) );
+			thr.notify( Alepha::build_exception< MyNotification >( "My message" ) );
 			thr.join();
 
 			return true;