sync: new internal sub-library for synchronous mpd_async calls

This library provides synchronous access to a mpd_async object.

Makefile.am

@@ -51,6 +51,7 @@ src_libmpdclient_la_SOURCES = \
 	src/status.c \
 	src/stats.c \
 	src/stored_playlist.c \
+	src/sync.c src/sync.h \
 	src/tag.c \
 	src/libmpdclient.c
 

src/sync.c

@@ -0,0 +1,160 @@
+/* libmpdclient
+   (c) 2003-2009 The Music Player Daemon Project
+   This project's homepage is: http://www.musicpd.org
+
+   Redistribution and use in source and binary forms, with or without
+   modification, are permitted provided that the following conditions
+   are met:
+
+   - Redistributions of source code must retain the above copyright
+   notice, this list of conditions and the following disclaimer.
+
+   - Redistributions in binary form must reproduce the above copyright
+   notice, this list of conditions and the following disclaimer in the
+   documentation and/or other materials provided with the distribution.
+
+   - Neither the name of the Music Player Daemon nor the names of its
+   contributors may be used to endorse or promote products derived from
+   this software without specific prior written permission.
+
+   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+   ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+   A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR
+   CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+   EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+   PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+   PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+   LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+   NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+   SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+#include "sync.h"
+#include <mpd/async.h>
+
+#include <assert.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <errno.h>
+
+static bool
+ignore_errno(int e)
+{
+#ifdef WIN32
+	return e == WSAEINTR || e == WSAEINPROGRESS;
+#else
+	return e == EINTR;
+#endif
+}
+
+static enum mpd_async_events
+mpd_sync_poll(struct mpd_async *async, struct timeval *tv)
+{
+	int fd;
+	fd_set rfds, wfds, efds;
+	int ret;
+	enum mpd_async_events events;
+
+	if (!mpd_async_is_alive(async))
+		return 0;
+
+	fd = mpd_async_fd(async);
+
+	while (1) {
+		events = mpd_async_events(async);
+		if (events == 0)
+			return 0;
+
+		FD_ZERO(&rfds);
+		FD_ZERO(&wfds);
+		FD_ZERO(&efds);
+
+		if (events & MPD_ASYNC_EVENT_READ)
+			FD_SET(fd, &rfds);
+		if (events & MPD_ASYNC_EVENT_WRITE)
+			FD_SET(fd, &wfds);
+		if (events & (MPD_ASYNC_EVENT_HUP|MPD_ASYNC_EVENT_ERROR))
+			FD_SET(fd, &efds);
+
+		ret = select(fd + 1, &rfds, &wfds, &efds, tv);
+		if (ret > 0) {
+			if (!FD_ISSET(fd, &rfds))
+				events &= ~MPD_ASYNC_EVENT_READ;
+			if (!FD_ISSET(fd, &wfds))
+				events &= ~MPD_ASYNC_EVENT_WRITE;
+			if (!FD_ISSET(fd, &efds))
+				events &= ~(MPD_ASYNC_EVENT_HUP|
+					    MPD_ASYNC_EVENT_ERROR);
+
+			return events;
+		}
+
+		if (ret == 0 || ignore_errno(errno))
+			return 0;
+	}
+}
+
+static bool
+mpd_sync_io(struct mpd_async *async, struct timeval *tv)
+{
+	enum mpd_async_events events = mpd_sync_poll(async, tv);
+
+	if (events)
+		return mpd_async_io(async, events);
+	else
+		return false;
+}
+
+bool
+mpd_sync_send_command_v(struct mpd_async *async, const struct timeval *tv0,
+			const char *command, va_list args)
+{
+	struct timeval tv = *tv0;
+	va_list copy;
+	bool success;
+
+	while (true) {
+		va_copy(copy, args);
+		success = mpd_async_send_command_v(async, command, copy);
+		va_end(copy);
+
+		if (success)
+			return true;
+
+		if (!mpd_async_is_alive(async) || !mpd_sync_io(async, &tv))
+			return false;
+	}
+}
+
+bool
+mpd_sync_send_command(struct mpd_async *async, const struct timeval *tv,
+		      const char *command, ...)
+{
+	va_list args;
+	bool success;
+
+	va_start(args, command);
+	success = mpd_sync_send_command_v(async, tv, command, args);
+	va_end(args);
+
+	return success;
+}
+
+char *
+mpd_sync_recv_line(struct mpd_async *async, const struct timeval *tv0)
+{
+	struct timeval tv = *tv0;
+	char *line;
+
+	while (true) {
+		line = mpd_async_recv_line(async);
+		if (line != NULL)
+			return line;
+
+		if (!mpd_async_is_alive(async) || !mpd_sync_io(async, &tv))
+			return NULL;
+	}
+}

src/sync.h

@@ -0,0 +1,69 @@
+/* libmpdclient
+   (c) 2003-2009 The Music Player Daemon Project
+   This project's homepage is: http://www.musicpd.org
+
+   Redistribution and use in source and binary forms, with or without
+   modification, are permitted provided that the following conditions
+   are met:
+
+   - Redistributions of source code must retain the above copyright
+   notice, this list of conditions and the following disclaimer.
+
+   - Redistributions in binary form must reproduce the above copyright
+   notice, this list of conditions and the following disclaimer in the
+   documentation and/or other materials provided with the distribution.
+
+   - Neither the name of the Music Player Daemon nor the names of its
+   contributors may be used to endorse or promote products derived from
+   this software without specific prior written permission.
+
+   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+   ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+   A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR
+   CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+   EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+   PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+   PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+   LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+   NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+   SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+/*! \file
+ * \brief Synchronous MPD connections
+ *
+ * This library provides synchronous access to a mpd_async object.
+ * For all operations, you may provide a timeout.
+ */
+
+#ifndef MPD_SYNC_H
+#define MPD_SYNC_H
+
+#include <stdbool.h>
+#include <stdarg.h>
+
+struct timeval;
+struct mpd_async;
+
+/**
+ * Synchronous wrapper for mpd_async_send_command_v().
+ */
+bool
+mpd_sync_send_command_v(struct mpd_async *async, const struct timeval *tv,
+			const char *command, va_list args);
+
+/**
+ * Synchronous wrapper for mpd_async_send_command().
+ */
+bool
+mpd_sync_send_command(struct mpd_async *async, const struct timeval *tv,
+		      const char *command, ...);
+
+/**
+ * Synchronous wrapper for mpd_async_recv_line().
+ */
+char *
+mpd_sync_recv_line(struct mpd_async *async, const struct timeval *tv);
+
+#endif