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-rw-r--r--src/output/plugins/FifoOutputPlugin.cxx307
1 files changed, 307 insertions, 0 deletions
diff --git a/src/output/plugins/FifoOutputPlugin.cxx b/src/output/plugins/FifoOutputPlugin.cxx
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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,
+};