Files
mpd/src/input/ThreadInputStream.cxx
2024-07-30 12:33:44 +02:00

191 lines
3.2 KiB
C++

// SPDX-License-Identifier: GPL-2.0-or-later
// Copyright The Music Player Daemon Project
#include "ThreadInputStream.hxx"
#include "thread/Name.hxx"
#include <cassert>
#include <string.h>
ThreadInputStream::ThreadInputStream(const char *_plugin,
const char *_uri,
Mutex &_mutex,
size_t _buffer_size) noexcept
:InputStream(_uri, _mutex),
plugin(_plugin),
thread(BIND_THIS_METHOD(ThreadFunc)),
allocation(_buffer_size)
{
allocation.SetName("InputStream");
allocation.ForkCow(false);
}
void
ThreadInputStream::Stop() noexcept
{
if (!thread.IsDefined())
return;
{
const std::scoped_lock lock{mutex};
close = true;
wake_cond.notify_one();
}
Cancel();
thread.Join();
buffer.Clear();
}
void
ThreadInputStream::Start()
{
thread.Start();
}
void
ThreadInputStream::ThreadSeek([[maybe_unused]] offset_type new_offset)
{
assert(!IsSeekable());
throw std::runtime_error{"Not seekable"};
}
inline void
ThreadInputStream::ThreadFunc() noexcept
{
FmtThreadName("input:{}", plugin);
std::unique_lock lock{mutex};
try {
Open();
} catch (...) {
postponed_exception = std::current_exception();
SetReady();
return;
}
/* we're ready, tell it to our client */
SetReady();
while (!close) {
assert(!postponed_exception);
if (IsSeeking()) {
const auto seek_offset_copy = offset = seek_offset;
seek_offset = UNKNOWN_SIZE;
eof = false;
buffer.Clear();
try {
const ScopeUnlock unlock(mutex);
ThreadSeek(seek_offset_copy);
} catch (...) {
postponed_exception = std::current_exception();
InvokeOnAvailable();
break;
}
offset = seek_offset_copy;
}
auto w = buffer.Write();
if (w.empty()) {
wake_cond.wait(lock);
} else {
size_t nbytes;
try {
const ScopeUnlock unlock(mutex);
nbytes = ThreadRead(w);
} catch (...) {
postponed_exception = std::current_exception();
caller_cond.notify_one();
InvokeOnAvailable();
break;
}
caller_cond.notify_one();
InvokeOnAvailable();
if (nbytes == 0) {
eof = true;
break;
}
buffer.Append(nbytes);
}
}
Close();
}
void
ThreadInputStream::Check()
{
assert(!thread.IsInside());
if (postponed_exception)
std::rethrow_exception(postponed_exception);
}
bool
ThreadInputStream::IsAvailable() const noexcept
{
assert(!thread.IsInside());
return !IsEOF() || postponed_exception;
}
void
ThreadInputStream::Seek([[maybe_unused]] std::unique_lock<Mutex> &lock,
offset_type new_offset)
{
seek_offset = new_offset;
wake_cond.notify_one();
}
size_t
ThreadInputStream::Read(std::unique_lock<Mutex> &lock,
std::span<std::byte> dest)
{
assert(!thread.IsInside());
while (true) {
if (postponed_exception)
std::rethrow_exception(postponed_exception);
if (IsSeeking()) {
caller_cond.wait(lock);
continue;
}
auto r = buffer.Read();
if (!r.empty()) {
size_t nbytes = std::min(dest.size(), r.size());
memcpy(dest.data(), r.data(), nbytes);
buffer.Consume(nbytes);
wake_cond.notify_one();
offset += nbytes;
return nbytes;
}
if (eof)
return 0;
caller_cond.wait(lock);
}
}
bool
ThreadInputStream::IsEOF() const noexcept
{
assert(!thread.IsInside());
return eof && buffer.empty() && !IsSeeking();
}