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Diffstat (limited to '')
-rw-r--r-- | src/output/plugins/FifoOutputPlugin.cxx | 313 |
1 files changed, 313 insertions, 0 deletions
diff --git a/src/output/plugins/FifoOutputPlugin.cxx b/src/output/plugins/FifoOutputPlugin.cxx new file mode 100644 index 000000000..6e3a4d332 --- /dev/null +++ b/src/output/plugins/FifoOutputPlugin.cxx @@ -0,0 +1,313 @@ +/* + * 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 { + struct audio_output base; + + AllocatedPath path; + std::string path_utf8; + + int input; + int output; + bool created; + Timer *timer; + + FifoOutput() + :path(AllocatedPath::Null()), input(-1), output(-1), + created(false) {} + + bool Initialize(const config_param ¶m, Error &error) { + return ao_base_init(&base, &fifo_output_plugin, param, + error); + } + + void Deinitialize() { + ao_base_finish(&base); + } + + 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 struct audio_output * +fifo_output_init(const config_param ¶m, 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)) { + fd->Deinitialize(); + delete fd; + return nullptr; + } + + return &fd->base; +} + +static void +fifo_output_finish(struct audio_output *ao) +{ + FifoOutput *fd = (FifoOutput *)ao; + + fd->Close(); + fd->Deinitialize(); + delete fd; +} + +static bool +fifo_output_open(struct audio_output *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(struct audio_output *ao) +{ + FifoOutput *fd = (FifoOutput *)ao; + + delete fd->timer; +} + +static void +fifo_output_cancel(struct audio_output *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(struct audio_output *ao) +{ + FifoOutput *fd = (FifoOutput *)ao; + + return fd->timer->IsStarted() + ? fd->timer->GetDelay() + : 0; +} + +static size_t +fifo_output_play(struct audio_output *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 audio_output_plugin 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, +}; |