ircd::ios: Employ the asio::executor abstraction w/ backward-compat.

construct/construct.cc

@@ -296,7 +296,7 @@ noexcept try
 
 	// Associates libircd with our io_context and posts the initial routines
 	// to that io_context. Execution of IRCd will then occur during ios::run()
-	ircd::init(ios);
+	ircd::init(ios.get_executor());
 
 	// If the user wants to immediately drop to an interactive command line
 	// without having to send a ctrl-c for it, that is provided here. This does

include/ircd/asio.h

@@ -52,12 +52,21 @@ namespace boost
 
 #pragma GCC visibility pop
 
-///
-/// The following IRCd headers are not included in the main stdinc.h list of
-/// includes because they require boost directly or symbols which we cannot
-/// forward declare. You should include this in your definition file if you
-/// need these low-level interfaces.
-///
+// Boost version dependent behavior for getting the io_service/io_context
+// abstract executor (recent versions) or the derived instance (old versions).
+namespace ircd::ios
+{
+	#if BOOST_VERSION >= 107000
+	asio::executor &get() noexcept;
+	#else
+	asio::io_context &get() noexcept;
+	#endif
+}
+
+// The following IRCd headers are not included in the main stdinc.h list of
+// includes because they require boost directly or symbols which we cannot
+// forward declare. You should include this in your definition file if you
+// need these low-level interfaces.
 
 // Context system headers depending on boost.
 #include <ircd/ctx/continuation.h>
@@ -65,4 +74,22 @@ namespace boost
 // Network system headers depending on boost.
 #include <ircd/net/asio.h>
 
+#if BOOST_VERSION >= 107000
+inline boost::asio::executor &
+ircd::ios::get()
+noexcept
+{
+	assert(bool(main));
+	return main;
+}
+#else
+inline boost::asio::io_context &
+ircd::ios::get()
+noexcept
+{
+	auto &context(const_cast<asio::execution_context &>(main.context()));
+	return static_cast<asio::io_context &>(context);
+}
+#endif
+
 #endif HAVE_IRCD_ASIO_H

include/ircd/ios.h

@@ -18,6 +18,7 @@
 /// Forward declarations for boost::asio because it is not included here.
 namespace boost::asio
 {
+	struct executor;
 	struct io_context;
 
 	template<class function>
@@ -43,23 +44,21 @@ namespace ircd::ios
 	struct post;
 
 	extern std::thread::id main_thread_id;
-	extern asio::io_context *user;
+	extern asio::executor user;
+	extern asio::executor main;
+
+	bool available() noexcept;
+	bool is_main_thread() noexcept;
+	void assert_main_thread();
 
 	const string_view &name(const descriptor &);
 	const string_view &name(const handler &);
-
-	bool is_main_thread();
-	void assert_main_thread();
-
-	bool available() noexcept;
-	asio::io_context &get() noexcept;
 	const uint64_t &epoch() noexcept;
 
 	void forked_parent();
 	void forked_child();
 	void forking();
-
-	void init(asio::io_context &user);
+	void init(asio::executor &&);
 }
 
 namespace ircd
@@ -286,6 +285,7 @@ ircd::ios::assert_main_thread()
 inline bool
 __attribute__((always_inline))
 ircd::ios::is_main_thread()
+noexcept
 {
 	return std::this_thread::get_id() == main_thread_id ||
 	       main_thread_id == std::thread::id();

include/ircd/ircd.h

@@ -116,9 +116,9 @@ namespace ircd
 	seconds uptime();
 
 	// Control panel
-	void init(boost::asio::io_context &ios);
 	void cont() noexcept;
 	bool quit() noexcept;
+	void init(boost::asio::executor &&);
 }
 
 #endif // HAVE_IRCD_IRCD_H

include/ircd/net/socket.h

@@ -112,8 +112,7 @@ struct ircd::net::socket
 	void connect(const endpoint &, const open_opts &, eptr_handler);
 	bool cancel() noexcept;
 
-	socket(asio::ssl::context &        = sslv23_client,
-	       boost::asio::io_service &   = ios::get());
+	socket(asio::ssl::context & = sslv23_client);
 
 	// Socket cannot be copied or moved; must be constructed as shared ptr
 	socket(socket &&) = delete;

ircd/ctx.cc

@@ -59,13 +59,27 @@ ircd::ctx::ctx::ios_desc
 /// Internal context struct ctor
 ircd::ctx::ctx::ctx(const string_view &name,
                     const size_t &stack_max,
-                    const context::flags &flags,
-                    boost::asio::io_service &ios)
-:name{name}
-,flags{flags}
-,strand{ios}
-,alarm{ios}
-,stack{stack_max}
+                    const context::flags &flags)
+:name
+{
+	name
+}
+,flags
+{
+	flags
+}
+,strand
+{
+	ios::get()
+}
+,alarm
+{
+	ios::get()
+}
+,stack
+{
+	stack_max
+}
 {
 }
 
@@ -1223,8 +1237,7 @@ ircd::ctx::context::context(const string_view &name,
 	(
 		name,
 		stack_sz,
-		!current? flags | POST : flags,
-		ios::get()
+		!current? flags | POST : flags
 	)
 }
 {

ircd/ctx.h

@@ -55,7 +55,7 @@ struct ircd::ctx::ctx
 	int8_t nice {0};                             // Scheduling priority nice-value
 	int8_t ionice {0};                           // IO priority nice-value (defaults for fs::opts)
 	int32_t notes {0};                           // norm: 0 = asleep; 1 = awake; inc by others; dec by self
-	boost::asio::io_service::strand strand;      // mutex/serializer
+	boost::asio::io_context::strand strand;      // mutex/serializer
 	boost::asio::deadline_timer alarm;           // acting semaphore (64B)
 	boost::asio::yield_context *yc {nullptr};    // boost interface
 	continuation *cont {nullptr};                // valid when asleep; invalid when awake
@@ -80,10 +80,9 @@ struct ircd::ctx::ctx
 	void operator()(boost::asio::yield_context, const std::function<void ()>) noexcept;
 	void spawn(context::function func);
 
-	ctx(const string_view &name                  = "<noname>"_sv,
-	    const size_t &stack_max                  = DEFAULT_STACK_SIZE,
-	    const context::flags &flags              = (context::flags)0U,
-	    boost::asio::io_service &ios             = ircd::ios::get());
+	ctx(const string_view &name     = "<noname>"_sv,
+	    const size_t &stack_max     = DEFAULT_STACK_SIZE,
+	    const context::flags &      = (context::flags)0U);
 
 	ctx(ctx &&) = delete;
 	ctx(const ctx &) = delete;

ircd/ios.cc

@@ -12,9 +12,14 @@
 decltype(ircd::ios::main_thread_id)
 ircd::ios::main_thread_id;
 
+/// The embedder/executable's (library user) asio::executor provided on init.
 decltype(ircd::ios::user)
 ircd::ios::user;
 
+/// Our library-specific/isolate executor.
+decltype(ircd::ios::main)
+ircd::ios::main;
+
 decltype(ircd::boost_version_api)
 ircd::boost_version_api
 {
@@ -37,7 +42,7 @@ ircd::boost_version_abi
 //
 
 void
-ircd::ios::init(asio::io_context &user)
+ircd::ios::init(asio::executor &&user)
 {
 	// Sample the ID of this thread. Since this is the first transfer of
 	// control to libircd after static initialization we have nothing to
@@ -47,7 +52,10 @@ ircd::ios::init(asio::io_context &user)
 	main_thread_id = std::this_thread::get_id();
 
 	// Set a reference to the user's ios_service
-	ios::user = &user;
+	ios::user = std::move(user);
+
+	// (simple passthru for now)
+	ios::main = ios::user;
 }
 
 //
@@ -306,19 +314,31 @@ namespace ircd::ios
 void
 ircd::ios::forking()
 {
-	get().notify_fork(asio::execution_context::fork_prepare);
+	#if BOOST_VERSION >= 107000
+		get().context().notify_fork(asio::execution_context::fork_prepare);
+	#else
+		get().notify_fork(asio::execution_context::fork_prepare);
+	#endif
 }
 
 void
 ircd::ios::forked_child()
 {
-	get().notify_fork(asio::execution_context::fork_child);
+	#if BOOST_VERSION >= 107000
+		get().context().notify_fork(asio::execution_context::fork_child);
+	#else
+		get().notify_fork(asio::execution_context::fork_child);
+	#endif
 }
 
 void
 ircd::ios::forked_parent()
 {
-	get().notify_fork(asio::execution_context::fork_parent);
+	#if BOOST_VERSION >= 107000
+		get().context().notify_fork(asio::execution_context::fork_parent);
+	#else
+		get().notify_fork(asio::execution_context::fork_parent);
+	#endif
 }
 
 //
@@ -522,19 +542,9 @@ ircd::ios::post::post(descriptor &descriptor,
 	boost::asio::post(get(), handle(descriptor, std::move(function)));
 }
 
-[[gnu::hot]]
-boost::asio::io_context &
-ircd::ios::get()
-noexcept
-{
-	assert(user);
-	return *user;
-}
-
-[[gnu::hot]]
 bool
 ircd::ios::available()
 noexcept
 {
-	return bool(user);
+	return bool(main);
 }

ircd/ircd.cc

@@ -102,16 +102,15 @@ decltype(ircd::main_context)
 ircd::main_context;
 
 /// Sets up the IRCd and its main context, then returns without blocking.
-//
-/// Pass your io_context instance, it will share it with the rest of your program.
-/// An exception will be thrown on error.
+///
+/// Pass the executor obtained from your io_context instance.
 ///
 /// This function will setup the main program loop of libircd. The execution will
 /// occur when your io_context.run() or poll() is further invoked.
 ///
 /// init() can only be called from a run::level::HALT state
 void
-ircd::init(boost::asio::io_context &user_ios)
+ircd::init(boost::asio::executor &&executor)
 try
 {
 	// This function must only be called from a HALT state.
@@ -122,7 +121,7 @@ try
 		};
 
 	// Setup the core event loop system starting with the user's supplied ios.
-	ios::init(user_ios);
+	ios::init(std::move(executor));
 
 	// The log is available. but it is console-only until conf opens files.
 	log::init();

ircd/net.cc

@@ -2692,11 +2692,10 @@ ircd::net::socket::total_calls_out
 // socket
 //
 
-ircd::net::socket::socket(asio::ssl::context &ssl,
-                          boost::asio::io_service &ios)
+ircd::net::socket::socket(asio::ssl::context &ssl)
 :sd
 {
-	ios
+	ios::get()
 }
 ,ssl
 {
@@ -2704,7 +2703,7 @@ ircd::net::socket::socket(asio::ssl::context &ssl,
 }
 ,timer
 {
-	ios
+	ios::get()
 }
 {
 	++instances;