Adding FIFO audio output. This is pretty much identical to the old one,

except that it now uses a timer for throttling.

git-svn-id: https://svn.musicpd.org/mpd/trunk@6621 09075e82-0dd4-0310-85a5-a0d7c8717e4f

1 files changed, 299 insertions, 0 deletions

diff --git a/src/audioOutputs/audioOutput_fifo.c b/src/audioOutputs/audioOutput_fifo.c
new file mode 100644
index 000000000..2fbbf5393
--- /dev/null
+++ b/src/audioOutputs/audioOutput_fifo.c
@@ -0,0 +1,299 @@
+/* the Music Player Daemon (MPD)
+ * Copyright (C) 2003-2007 by Warren Dukes (warren.dukes@gmail.com)
+ * This project's homepage is: http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include "../audioOutput.h"
+
+#include <stdlib.h>
+
+#ifdef HAVE_FIFO
+
+#include "../log.h"
+#include "../conf.h"
+#include "../utils.h"
+#include "../timer.h"
+
+#include <errno.h>
+#include <fcntl.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+
+#define FIFO_BUFFER_SIZE 65536 /* pipe capacity on Linux >= 2.6.11 */
+
+typedef struct _FifoData {
+	char *path;
+	int input;
+	int output;
+	int created;
+	Timer *timer;
+} FifoData;
+
+static FifoData *newFifoData()
+{
+	FifoData *ret;
+
+	ret = xmalloc(sizeof(FifoData));
+
+	ret->path = NULL;
+	ret->input = -1;
+	ret->output = -1;
+	ret->created = 0;
+	ret->timer = NULL;
+	
+	return ret;
+}
+
+static void freeFifoData(FifoData *fd)
+{
+	if (fd->path)
+		free(fd->path);
+
+	if (fd->timer)
+		timer_free(fd->timer);
+
+	free(fd);
+}
+
+static void removeFifo(FifoData *fd)
+{
+	DEBUG("Removing FIFO \"%s\"\n", fd->path);
+
+	if (unlink(fd->path) < 0) {
+		ERROR("Could not remove FIFO \"%s\": %s\n",
+		      fd->path, strerror(errno));
+		return;
+	}
+
+	fd->created = 0;
+}
+
+static void closeFifo(FifoData *fd)
+{
+	struct stat st;
+
+	if (fd->input >= 0) {
+		close(fd->input);
+		fd->input = -1;
+	}
+
+	if (fd->output >= 0) {
+		close(fd->output);
+		fd->output = -1;
+	}
+
+	if (fd->created && (stat(fd->path, &st) == 0))
+		removeFifo(fd);
+}
+
+static int makeFifo(FifoData *fd)
+{
+	if (mkfifo(fd->path, 0666) < 0) {
+		ERROR("Couldn't create FIFO \"%s\": %s\n",
+		      fd->path, strerror(errno));
+		return -1;
+	}
+
+	fd->created = 1;
+
+	return 0;
+}
+
+static int checkFifo(FifoData *fd)
+{
+	struct stat st;
+
+	if (stat(fd->path, &st) < 0) {
+		if (errno == ENOENT) {
+			/* Path doesn't exist */
+			return makeFifo(fd);
+		}
+
+		ERROR("Failed to stat FIFO \"%s\": %s\n",
+		      fd->path, strerror(errno));
+		return -1;
+	}
+
+	if (!S_ISFIFO(st.st_mode)) {
+		ERROR("\"%s\" already exists, but is not a FIFO\n", fd->path);
+		return -1;
+	}
+
+	return 0;
+}
+
+static int openFifo(FifoData *fd)
+{
+	if (checkFifo(fd) < 0)
+		return -1;
+
+	fd->input = open(fd->path, O_RDONLY|O_NONBLOCK);
+	if (fd->input < 0) {
+		ERROR("Could not open FIFO \"%s\" for reading: %s\n",
+		      fd->path, strerror(errno));
+		closeFifo(fd);
+		return -1;
+	}
+
+	fd->output = open(fd->path, O_WRONLY|O_NONBLOCK);
+	if (fd->output < 0) {
+		ERROR("Could not open FIFO \"%s\" for writing: %s\n",
+		      fd->path, strerror(errno));
+		closeFifo(fd);
+		return -1;
+	}
+
+	return 0;
+}
+
+static int fifo_initDriver(AudioOutput *audioOutput, ConfigParam *param)
+{
+	FifoData *fd;
+	BlockParam *path = NULL;
+
+	if (param)
+		path = getBlockParam(param, "path");
+
+	if (!path) {
+		FATAL("No \"path\" parameter specified for fifo output "
+		      "defined at line %i\n", param->line);
+	}
+
+	if (path->value[0] != '/') {
+		FATAL("\"path\" parameter for fifo output is not an absolute "
+		      "path at line %i\n", param->line);
+	}
+
+	fd = newFifoData();
+	fd->path = xstrdup(path->value);
+	audioOutput->data = fd;
+
+	if (openFifo(fd) < 0) {
+		freeFifoData(fd);
+		return -1;
+	}
+
+	return 0;
+}
+
+static void fifo_finishDriver(AudioOutput *audioOutput)
+{
+	FifoData *fd = (FifoData *)audioOutput->data;
+
+	closeFifo(fd);
+	freeFifoData(fd);
+}
+
+static int fifo_openDevice(AudioOutput *audioOutput)
+{
+	FifoData *fd = (FifoData *)audioOutput->data;
+
+	if (fd->timer)
+		timer_free(fd->timer);
+
+	fd->timer = timer_new(&audioOutput->outAudioFormat);
+
+	audioOutput->open = 1;
+
+	return 0;
+}
+
+static void fifo_closeDevice(AudioOutput *audioOutput)
+{
+	FifoData *fd = (FifoData *)audioOutput->data;
+
+	if (fd->timer) {
+		timer_free(fd->timer);
+		fd->timer = NULL;
+	}
+
+	audioOutput->open = 0;
+}
+
+static void fifo_dropBufferedAudio(AudioOutput *audioOutput)
+{
+	FifoData *fd = (FifoData *)audioOutput->data;
+	char buf[FIFO_BUFFER_SIZE];
+	int bytes = 1;
+
+	timer_reset(fd->timer);
+
+	while (bytes > 0 && errno != EINTR)
+		bytes = read(fd->input, buf, FIFO_BUFFER_SIZE);
+
+	if (bytes < 0 && errno != EAGAIN) {
+		WARNING("Flush of FIFO \"%s\" failed: %s\n",
+		        fd->path, strerror(errno));
+	}
+}
+
+static int fifo_playAudio(AudioOutput *audioOutput, char *playChunk, int size)
+{
+	FifoData *fd = (FifoData *)audioOutput->data;
+	int offset = 0;
+	int bytes;
+
+	if (!fd->timer->started)
+		timer_start(fd->timer);
+	else
+		timer_sync(fd->timer);
+
+	timer_add(fd->timer, size);
+
+	while (size) {
+		bytes = write(fd->output, playChunk + offset, size);
+		if (bytes < 0) {
+			switch (errno) {
+			case EAGAIN:
+				/* The pipe is full, so empty it */
+				fifo_dropBufferedAudio(audioOutput);
+				continue;
+			case EINTR:
+				continue;
+			}
+
+			ERROR("Closing FIFO output \"%s\" due to write error: "
+			      "%s\n", fd->path, strerror(errno));
+			fifo_closeDevice(audioOutput);
+			return -1;
+		}
+
+		size -= bytes;
+		offset += bytes;
+	}
+
+	return 0;
+}
+
+AudioOutputPlugin fifoPlugin = {
+	"fifo",
+	NULL, /* testDefaultDeviceFunc */
+	fifo_initDriver,
+	fifo_finishDriver,
+	fifo_openDevice,
+	fifo_playAudio,
+	fifo_dropBufferedAudio,
+	fifo_closeDevice,
+	NULL, /* sendMetadataFunc */
+};
+
+#else /* HAVE_FIFO */
+
+DISABLED_AUDIO_OUTPUT_PLUGIN(fifoPlugin)
+
+#endif /* !HAVE_FIFO */