1 files changed, 307 insertions, 0 deletions
diff --git a/src/output/plugins/FifoOutputPlugin.cxx b/src/output/plugins/FifoOutputPlugin.cxx
new file mode 100644
index 000000000..9df5a74dd
--- /dev/null
+++ b/src/output/plugins/FifoOutputPlugin.cxx
@@ -0,0 +1,307 @@
+/*
+ * Copyright (C) 2003-2014 The Music Player Daemon Project
+ * 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.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "config.h"
+#include "FifoOutputPlugin.hxx"
+#include "config/ConfigError.hxx"
+#include "../OutputAPI.hxx"
+#include "../Timer.hxx"
+#include "fs/AllocatedPath.hxx"
+#include "fs/FileSystem.hxx"
+#include "util/Error.hxx"
+#include "util/Domain.hxx"
+#include "Log.hxx"
+#include "open.h"
+
+#include <sys/stat.h>
+#include <errno.h>
+#include <unistd.h>
+
+#define FIFO_BUFFER_SIZE 65536 /* pipe capacity on Linux >= 2.6.11 */
+
+struct FifoOutput {
+	AudioOutput base;
+
+	AllocatedPath path;
+	std::string path_utf8;
+
+	int input;
+	int output;
+	bool created;
+	Timer *timer;
+
+	FifoOutput()
+		:base(fifo_output_plugin),
+		 path(AllocatedPath::Null()), input(-1), output(-1),
+		 created(false) {}
+
+	bool Initialize(const config_param &param, Error &error) {
+		return base.Configure(param, error);
+	}
+
+	bool Create(Error &error);
+	bool Check(Error &error);
+	void Delete();
+
+	bool Open(Error &error);
+	void Close();
+};
+
+static constexpr Domain fifo_output_domain("fifo_output");
+
+inline void
+FifoOutput::Delete()
+{
+	FormatDebug(fifo_output_domain,
+		    "Removing FIFO \"%s\"", path_utf8.c_str());
+
+	if (!RemoveFile(path)) {
+		FormatErrno(fifo_output_domain,
+			    "Could not remove FIFO \"%s\"",
+			    path_utf8.c_str());
+		return;
+	}
+
+	created = false;
+}
+
+void
+FifoOutput::Close()
+{
+	if (input >= 0) {
+		close(input);
+		input = -1;
+	}
+
+	if (output >= 0) {
+		close(output);
+		output = -1;
+	}
+
+	struct stat st;
+	if (created && StatFile(path, st))
+		Delete();
+}
+
+inline bool
+FifoOutput::Create(Error &error)
+{
+	if (!MakeFifo(path, 0666)) {
+		error.FormatErrno("Couldn't create FIFO \"%s\"",
+				  path_utf8.c_str());
+		return false;
+	}
+
+	created = true;
+	return true;
+}
+
+inline bool
+FifoOutput::Check(Error &error)
+{
+	struct stat st;
+	if (!StatFile(path, st)) {
+		if (errno == ENOENT) {
+			/* Path doesn't exist */
+			return Create(error);
+		}
+
+		error.FormatErrno("Failed to stat FIFO \"%s\"",
+				  path_utf8.c_str());
+		return false;
+	}
+
+	if (!S_ISFIFO(st.st_mode)) {
+		error.Format(fifo_output_domain,
+			     "\"%s\" already exists, but is not a FIFO",
+			     path_utf8.c_str());
+		return false;
+	}
+
+	return true;
+}
+
+inline bool
+FifoOutput::Open(Error &error)
+{
+	if (!Check(error))
+		return false;
+
+	input = OpenFile(path, O_RDONLY|O_NONBLOCK|O_BINARY, 0);
+	if (input < 0) {
+		error.FormatErrno("Could not open FIFO \"%s\" for reading",
+				  path_utf8.c_str());
+		Close();
+		return false;
+	}
+
+	output = OpenFile(path, O_WRONLY|O_NONBLOCK|O_BINARY, 0);
+	if (output < 0) {
+		error.FormatErrno("Could not open FIFO \"%s\" for writing",
+				  path_utf8.c_str());
+		Close();
+		return false;
+	}
+
+	return true;
+}
+
+static bool
+fifo_open(FifoOutput *fd, Error &error)
+{
+	return fd->Open(error);
+}
+
+static AudioOutput *
+fifo_output_init(const config_param &param, Error &error)
+{
+	FifoOutput *fd = new FifoOutput();
+
+	fd->path = param.GetBlockPath("path", error);
+	if (fd->path.IsNull()) {
+		delete fd;
+
+		if (!error.IsDefined())
+			error.Set(config_domain,
+				  "No \"path\" parameter specified");
+		return nullptr;
+	}
+
+	fd->path_utf8 = fd->path.ToUTF8();
+
+	if (!fd->Initialize(param, error)) {
+		delete fd;
+		return nullptr;
+	}
+
+	if (!fifo_open(fd, error)) {
+		delete fd;
+		return nullptr;
+	}
+
+	return &fd->base;
+}
+
+static void
+fifo_output_finish(AudioOutput *ao)
+{
+	FifoOutput *fd = (FifoOutput *)ao;
+
+	fd->Close();
+	delete fd;
+}
+
+static bool
+fifo_output_open(AudioOutput *ao, AudioFormat &audio_format,
+		 gcc_unused Error &error)
+{
+	FifoOutput *fd = (FifoOutput *)ao;
+
+	fd->timer = new Timer(audio_format);
+
+	return true;
+}
+
+static void
+fifo_output_close(AudioOutput *ao)
+{
+	FifoOutput *fd = (FifoOutput *)ao;
+
+	delete fd->timer;
+}
+
+static void
+fifo_output_cancel(AudioOutput *ao)
+{
+	FifoOutput *fd = (FifoOutput *)ao;
+	char buf[FIFO_BUFFER_SIZE];
+	int bytes = 1;
+
+	fd->timer->Reset();
+
+	while (bytes > 0 && errno != EINTR)
+		bytes = read(fd->input, buf, FIFO_BUFFER_SIZE);
+
+	if (bytes < 0 && errno != EAGAIN) {
+		FormatErrno(fifo_output_domain,
+			    "Flush of FIFO \"%s\" failed",
+			    fd->path_utf8.c_str());
+	}
+}
+
+static unsigned
+fifo_output_delay(AudioOutput *ao)
+{
+	FifoOutput *fd = (FifoOutput *)ao;
+
+	return fd->timer->IsStarted()
+		? fd->timer->GetDelay()
+		: 0;
+}
+
+static size_t
+fifo_output_play(AudioOutput *ao, const void *chunk, size_t size,
+		 Error &error)
+{
+	FifoOutput *fd = (FifoOutput *)ao;
+	ssize_t bytes;
+
+	if (!fd->timer->IsStarted())
+		fd->timer->Start();
+	fd->timer->Add(size);
+
+	while (true) {
+		bytes = write(fd->output, chunk, size);
+		if (bytes > 0)
+			return (size_t)bytes;
+
+		if (bytes < 0) {
+			switch (errno) {
+			case EAGAIN:
+				/* The pipe is full, so empty it */
+				fifo_output_cancel(&fd->base);
+				continue;
+			case EINTR:
+				continue;
+			}
+
+			error.FormatErrno("Failed to write to FIFO %s",
+					  fd->path_utf8.c_str());
+			return 0;
+		}
+	}
+}
+
+const struct AudioOutputPlugin fifo_output_plugin = {
+	"fifo",
+	nullptr,
+	fifo_output_init,
+	fifo_output_finish,
+	nullptr,
+	nullptr,
+	fifo_output_open,
+	fifo_output_close,
+	fifo_output_delay,
+	nullptr,
+	fifo_output_play,
+	nullptr,
+	fifo_output_cancel,
+	nullptr,
+	nullptr,
+};