d0fbf6db59
This adds a bit of overhead, but also adds flexibility to the API, because arbitrary triggers may be invoked from that virtual method implementation, not just Cond::signal(). The motivation for this is to make the handlers more dynamic, for the upcoming buffering class utilizing ProxyInputStream.
169 lines
3.2 KiB
C++
169 lines
3.2 KiB
C++
/*
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* Copyright 2003-2017 The Music Player Daemon Project
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* http://www.musicpd.org
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#include "config.h"
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#include "ThreadInputStream.hxx"
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#include "CondHandler.hxx"
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#include "thread/Name.hxx"
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#include <assert.h>
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#include <string.h>
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ThreadInputStream::ThreadInputStream(const char *_plugin,
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const char *_uri,
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Mutex &_mutex,
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size_t _buffer_size) noexcept
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:InputStream(_uri, _mutex),
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plugin(_plugin),
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thread(BIND_THIS_METHOD(ThreadFunc)),
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allocation(_buffer_size),
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buffer(&allocation.front(), allocation.size())
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{
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allocation.ForkCow(false);
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}
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void
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ThreadInputStream::Stop() noexcept
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{
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if (!thread.IsDefined())
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return;
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{
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const std::lock_guard<Mutex> lock(mutex);
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close = true;
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wake_cond.signal();
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}
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Cancel();
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thread.Join();
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buffer.Clear();
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}
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void
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ThreadInputStream::Start()
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{
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thread.Start();
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}
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inline void
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ThreadInputStream::ThreadFunc() noexcept
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{
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FormatThreadName("input:%s", plugin);
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const std::lock_guard<Mutex> lock(mutex);
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try {
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Open();
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} catch (...) {
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postponed_exception = std::current_exception();
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SetReady();
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return;
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}
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/* we're ready, tell it to our client */
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SetReady();
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while (!close) {
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assert(!postponed_exception);
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auto w = buffer.Write();
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if (w.empty()) {
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wake_cond.wait(mutex);
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} else {
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size_t nbytes;
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try {
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const ScopeUnlock unlock(mutex);
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nbytes = ThreadRead(w.data, w.size);
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} catch (...) {
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postponed_exception = std::current_exception();
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InvokeOnAvailable();
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break;
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}
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InvokeOnAvailable();
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if (nbytes == 0) {
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eof = true;
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break;
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}
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buffer.Append(nbytes);
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}
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}
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Close();
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}
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void
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ThreadInputStream::Check()
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{
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assert(!thread.IsInside());
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if (postponed_exception)
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std::rethrow_exception(postponed_exception);
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}
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bool
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ThreadInputStream::IsAvailable() noexcept
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{
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assert(!thread.IsInside());
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return !buffer.empty() || eof || postponed_exception;
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}
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inline size_t
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ThreadInputStream::Read(void *ptr, size_t read_size)
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{
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assert(!thread.IsInside());
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CondInputStreamHandler cond_handler;
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while (true) {
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if (postponed_exception)
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std::rethrow_exception(postponed_exception);
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auto r = buffer.Read();
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if (!r.empty()) {
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size_t nbytes = std::min(read_size, r.size);
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memcpy(ptr, r.data, nbytes);
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buffer.Consume(nbytes);
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wake_cond.broadcast();
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offset += nbytes;
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return nbytes;
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}
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if (eof)
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return 0;
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const ScopeExchangeInputStreamHandler h(*this, &cond_handler);
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cond_handler.cond.wait(mutex);
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}
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}
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bool
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ThreadInputStream::IsEOF() noexcept
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{
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assert(!thread.IsInside());
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return eof;
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}
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