ircd::fs: Simplify API/AIO by eliminating callback: ctx yield only for now.

include/ircd/fs/read.h

@@ -23,11 +23,6 @@
 namespace ircd::fs
 {
 	struct read_opts extern const read_opts_default;
-	using read_callback = std::function<void (std::exception_ptr, const string_view &)>;
-
-	// Asynchronous callback-based read into buffer; callback views read portion.
-	void read(const string_view &path, const mutable_raw_buffer &, const read_opts &, read_callback);
-	void read(const string_view &path, const mutable_raw_buffer &, read_callback);
 
 	// Yields ircd::ctx for read into buffer; returns view of read portion.
 	string_view read(const string_view &path, const mutable_raw_buffer &, const read_opts & = read_opts_default);
@@ -53,11 +48,3 @@ inline
 ircd::fs::read_opts::read_opts(const off_t &offset)
 :offset{offset}
 {}
-
-inline void
-ircd::fs::read(const string_view &path,
-               const mutable_raw_buffer &buf,
-               read_callback callback)
-{
-	return read(path, buf, read_opts_default, std::move(callback));
-}

ircd/aio.h

@@ -52,16 +52,12 @@ struct ircd::fs::aio
 	};
 
 	/// Handler to the io context we submit requests to the kernel with
-	aio_context_t idp
+	aio_context_t idp{0};
-	{
-		0
-	};
 
 	// Callback stack invoked when the sigfd is notified of completed events.
 	void handle_event(const io_event &) noexcept;
 	void handle_events() noexcept;
 	void handle(const error_code &, const size_t) noexcept;
-
 	void set_handle();
 
 	aio()
@@ -87,8 +83,6 @@ struct ircd::fs::aio::request
 	ssize_t retval {0};
 	ssize_t errcode {0};
 	ctx::ctx *waiter {nullptr};
-	bool close_fd {false};
-	bool free_req {false};
 
 	/// called if close_fd is true
 	void close_fildes() noexcept;
@@ -288,18 +282,6 @@ noexcept try
 	           request->retval,
 	           request->errcode);
 */
-	const unwind cleanup{[&request]
-	{
-		// The user might want us to cleanup their fd after this event
-		if(request->close_fd)
-			request->close_fildes();
-
-		// The user might want us to free a dynamically allocated request struct
-		// to simplify their callback sequence. The noexcept guarantees h
-		if(request->free_req)
-			delete request;
-	}};
-
 	// virtual dispatch based on the request type. Alternatively, we could
 	// switch() on the iocb lio_opcode and downcast... but that's what vtable
 	// does for us right here.
@@ -335,7 +317,6 @@ catch(const std::exception &e)
 
 namespace ircd::fs
 {
-	void read__aio(const string_view &path, const mutable_raw_buffer &, const read_opts &, read_callback);
 	string_view read__aio(const string_view &path, const mutable_raw_buffer &, const read_opts &);
 	std::string read__aio(const string_view &path, const read_opts &);
 }
@@ -344,19 +325,15 @@ namespace ircd::fs
 struct ircd::fs::aio::request::read
 :request
 {
-	read_callback callback;
-
 	virtual void handle() final override;
 
-	read(const int &fd, const mutable_raw_buffer &buf, const read_opts &opts, read_callback callback);
+	read(const int &fd, const mutable_raw_buffer &buf, const read_opts &opts);
 };
 
 ircd::fs::aio::request::read::read(const int &fd,
                                    const mutable_raw_buffer &buf,
-                                   const read_opts &opts,
+                                   const read_opts &opts)
-                                   read_callback callback)
 :request{fd}
-,callback{std::move(callback)}
 {
 	aio_data = uintptr_t(this);
 	aio_reqprio = opts.priority;
@@ -370,33 +347,13 @@ ircd::fs::aio::request::read::read(const int &fd,
 void
 ircd::fs::aio::request::read::handle()
 {
-	if(waiter)
+	if(!waiter)
-	{
+		return;
+
 	ircd::ctx::notify(*waiter);
 	waiter = nullptr;
 }
 
-	if(callback)
-	{
-		const size_t bytes
-		{
-			retval >= 0? size_t(retval) : 0
-		};
-
-		const string_view view
-		{
-			reinterpret_cast<const char *>(aio_buf), bytes
-		};
-
-		std::exception_ptr eptr
-		{
-			errcode != 0? make_system_error(errcode) : std::exception_ptr{}
-		};
-
-		callback(std::move(eptr), view);
-	}
-}
-
 //
 // Interface
 //
@@ -419,8 +376,6 @@ ircd::fs::read__aio(const string_view &path,
 		syscall(::close, fd);
 	}};
 
-	// This fstat may be defeating; to be sure, don't use this overload
-	// and progressively buffer chunks into your application.
 	struct stat stat;
 	syscall(::fstat, fd, &stat);
 	const auto &size
@@ -436,7 +391,7 @@ ircd::fs::read__aio(const string_view &path,
 
 	aio::request::read request
 	{
-		int(fd), buf, opts, nullptr
+		int(fd), buf, opts
 	};
 
 	const size_t bytes
@@ -469,7 +424,7 @@ ircd::fs::read__aio(const string_view &path,
 
 	aio::request::read request
 	{
-		int(fd), buf, opts, nullptr
+		int(fd), buf, opts
 	};
 
 	const size_t bytes
@@ -484,33 +439,3 @@ ircd::fs::read__aio(const string_view &path,
 
 	return view;
 }
-
-void
-ircd::fs::read__aio(const string_view &path,
-                    const mutable_raw_buffer &buf,
-                    const read_opts &opts,
-                    read_callback callback)
-{
-	static thread_local char pathstr[2048];
-	strlcpy(pathstr, path, sizeof(pathstr));
-
-	const auto fd
-	{
-		syscall(::open, pathstr, O_CLOEXEC, O_RDONLY)
-	};
-
-	const unwind::exceptional cfd{[&fd]
-	{
-		syscall(::close, fd);
-	}};
-
-	auto request
-	{
-		std::make_unique<aio::request::read>(int(fd), buf, opts, std::move(callback))
-	};
-
-	request->close_fd = true;
-	request->free_req = true;
-	(*request)();
-	request.release();
-}

ircd/fs.cc

@@ -78,7 +78,6 @@ noexcept
 
 namespace ircd::fs
 {
-	void read__std(const string_view &path, const mutable_raw_buffer &, const read_opts &, read_callback);
 	string_view read__std(const string_view &path, const mutable_raw_buffer &, const read_opts &);
 	std::string read__std(const string_view &path, const read_opts &);
 }
@@ -116,20 +115,6 @@ ircd::fs::read(const string_view &path,
 	return read__std(path, buf, opts);
 }
 
-void
-ircd::fs::read(const string_view &path,
-               const mutable_raw_buffer &buf,
-               const read_opts &opts,
-               read_callback callback)
-{
-	#ifdef IRCD_USE_AIO
-	if(likely(aioctx))
-		return read__aio(path, buf, opts, std::move(callback));
-	#endif
-
-	return read__std(path, buf, opts, std::move(callback));
-}
-
 //
 // std read
 //
@@ -149,43 +134,15 @@ ircd::string_view
 ircd::fs::read__std(const string_view &path,
                     const mutable_raw_buffer &buf,
                     const read_opts &opts)
-{
-	string_view ret;
-	std::exception_ptr reptr;
-	read(path, buf, opts, [&reptr, &ret]
-	(std::exception_ptr eptr, const string_view &view)
-	{
-		reptr = std::move(eptr);
-		ret = view;
-	});
-
-	if(reptr)
-		std::rethrow_exception(reptr);
-
-	return ret;
-}
-
-void
-ircd::fs::read__std(const string_view &path,
-                    const mutable_raw_buffer &buf,
-                    const read_opts &opts,
-                    read_callback callback)
-try
 {
 	std::ifstream file{std::string{path}};
 	file.exceptions(file.failbit | file.badbit);
 	file.seekg(opts.offset, file.beg);
 	file.read(reinterpret_cast<char *>(data(buf)), size(buf));
-	const string_view view
+	return
 	{
 		reinterpret_cast<const char *>(data(buf)), size_t(file.gcount())
 	};
-
-	callback(std::exception_ptr{}, view);
-}
-catch(...)
-{
-	callback(std::make_exception_ptr(std::current_exception()), string_view{});
 }