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/*
* 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.
*/
#ifndef MPD_NFS_CANCELLABLE_HXX
#define MPD_NFS_CANCELLABLE_HXX
#include "Compiler.h"
#include <boost/intrusive/list.hpp>
#include <algorithm>
#include <assert.h>
template<typename T>
class CancellablePointer
: public boost::intrusive::list_base_hook<boost::intrusive::link_mode<boost::intrusive::normal_link>> {
public:
typedef T *pointer_type;
typedef T &reference_type;
typedef const T &const_reference_type;
private:
pointer_type p;
public:
explicit CancellablePointer(reference_type _p):p(&_p) {}
CancellablePointer(const CancellablePointer &) = delete;
constexpr bool IsCancelled() const {
return p == nullptr;
}
void Cancel() {
assert(!IsCancelled());
p = nullptr;
}
reference_type Get() {
assert(p != nullptr);
return *p;
}
constexpr bool Is(const_reference_type other) const {
return p == &other;
}
};
template<typename T, typename CT=CancellablePointer<T>>
class CancellableList {
public:
typedef typename CT::reference_type reference_type;
typedef typename CT::const_reference_type const_reference_type;
private:
typedef boost::intrusive::list<CT,
boost::intrusive::constant_time_size<false>> List;
typedef typename List::iterator iterator;
typedef typename List::const_iterator const_iterator;
List list;
class MatchPointer {
const_reference_type p;
public:
explicit constexpr MatchPointer(const_reference_type _p)
:p(_p) {}
constexpr bool operator()(const CT &a) const {
return a.Is(p);
}
};
gcc_pure
iterator Find(reference_type p) {
return std::find_if(list.begin(), list.end(), MatchPointer(p));
}
gcc_pure
const_iterator Find(const_reference_type p) const {
return std::find_if(list.begin(), list.end(), MatchPointer(p));
}
gcc_pure
iterator Find(CT &c) {
return list.iterator_to(c);
}
gcc_pure
const_iterator Find(const CT &c) const {
return list.iterator_to(c);
}
public:
#ifndef NDEBUG
gcc_pure
bool IsEmpty() const {
for (const auto &c : list)
if (!c.IsCancelled())
return false;
return true;
}
#endif
gcc_pure
bool Contains(const_reference_type p) const {
return Find(p) != list.end();
}
template<typename... Args>
CT &Add(reference_type p, Args&&... args) {
assert(Find(p) == list.end());
CT *c = new CT(p, std::forward<Args>(args)...);
list.push_back(*c);
return *c;
}
void Remove(CT &ct) {
auto i = Find(ct);
assert(i != list.end());
list.erase(i);
delete &ct;
}
void Cancel(reference_type p) {
auto i = Find(p);
assert(i != list.end());
i->Cancel();
}
};
#endif
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