mpd/src/input/InputStream.cxx
2014-01-24 16:33:33 +01:00

215 lines
3.9 KiB
C++

/*
* 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 "InputStream.hxx"
#include "Registry.hxx"
#include "InputPlugin.hxx"
#include "plugins/RewindInputPlugin.hxx"
#include "util/UriUtil.hxx"
#include "util/Error.hxx"
#include "util/Domain.hxx"
#include <assert.h>
#include <stdio.h> /* for SEEK_SET */
static constexpr Domain input_domain("input");
InputStream *
InputStream::Open(const char *url,
Mutex &mutex, Cond &cond,
Error &error)
{
input_plugins_for_each_enabled(plugin) {
InputStream *is;
is = plugin->open(url, mutex, cond, error);
if (is != nullptr) {
assert(is->plugin.close != nullptr);
assert(is->plugin.read != nullptr);
assert(is->plugin.eof != nullptr);
assert(!is->seekable || is->plugin.seek != nullptr);
is = input_rewind_open(is);
return is;
} else if (error.IsDefined())
return nullptr;
}
error.Set(input_domain, "Unrecognized URI");
return nullptr;
}
InputStream *
InputStream::OpenReady(const char *uri,
Mutex &mutex, Cond &cond,
Error &error)
{
InputStream *is = Open(uri, mutex, cond, error);
if (is == nullptr)
return nullptr;
mutex.lock();
is->WaitReady();
bool success = is->Check(error);
mutex.unlock();
if (!success) {
is->Close();
is = nullptr;
}
return is;
}
bool
InputStream::Check(Error &error)
{
return plugin.check == nullptr || plugin.check(this, error);
}
void
InputStream::Update()
{
if (plugin.update != nullptr)
plugin.update(this);
}
void
InputStream::WaitReady()
{
while (true) {
Update();
if (ready)
break;
cond.wait(mutex);
}
}
void
InputStream::LockWaitReady()
{
const ScopeLock protect(mutex);
WaitReady();
}
bool
InputStream::CheapSeeking() const
{
return IsSeekable() && !uri_has_scheme(uri.c_str());
}
bool
InputStream::Seek(offset_type _offset, int whence, Error &error)
{
if (plugin.seek == nullptr)
return false;
return plugin.seek(this, _offset, whence, error);
}
bool
InputStream::LockSeek(offset_type _offset, int whence, Error &error)
{
if (plugin.seek == nullptr)
return false;
const ScopeLock protect(mutex);
return Seek(_offset, whence, error);
}
bool
InputStream::Rewind(Error &error)
{
return Seek(0, SEEK_SET, error);
}
bool
InputStream::LockRewind(Error &error)
{
return LockSeek(0, SEEK_SET, error);
}
Tag *
InputStream::ReadTag()
{
return plugin.tag != nullptr
? plugin.tag(this)
: nullptr;
}
Tag *
InputStream::LockReadTag()
{
if (plugin.tag == nullptr)
return nullptr;
const ScopeLock protect(mutex);
return ReadTag();
}
bool
InputStream::IsAvailable()
{
return plugin.available != nullptr
? plugin.available(this)
: true;
}
size_t
InputStream::Read(void *ptr, size_t _size, Error &error)
{
assert(ptr != nullptr);
assert(_size > 0);
return plugin.read(this, ptr, _size, error);
}
size_t
InputStream::LockRead(void *ptr, size_t _size, Error &error)
{
assert(ptr != nullptr);
assert(_size > 0);
const ScopeLock protect(mutex);
return Read(ptr, _size, error);
}
void
InputStream::Close()
{
plugin.close(this);
}
bool
InputStream::IsEOF()
{
return plugin.eof(this);
}
bool
InputStream::LockIsEOF()
{
const ScopeLock protect(mutex);
return IsEOF();
}