aria2/src/SharedHandle.h

454 lines
10 KiB
C++

/* <!-- copyright */
/*
* aria2 - The high speed download utility
*
* Copyright (C) 2006 Tatsuhiro Tsujikawa
*
* 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
*
* In addition, as a special exception, the copyright holders give
* permission to link the code of portions of this program with the
* OpenSSL library under certain conditions as described in each
* individual source file, and distribute linked combinations
* including the two.
* You must obey the GNU General Public License in all respects
* for all of the code used other than OpenSSL. If you modify
* file(s) with this exception, you may extend this exception to your
* version of the file(s), but you are not obligated to do so. If you
* do not wish to do so, delete this exception statement from your
* version. If you delete this exception statement from all source
* files in the program, then also delete it here.
*/
/* copyright --> */
#ifndef D_SHARED_HANDLE_H
#define D_SHARED_HANDLE_H
#include <cassert>
#include <iosfwd>
#include <algorithm>
// To Use std::tr1::shared_ptr uncomment following few lines and
// comment out SharedHandle stuff.
//
// #include <tr1/memory>
// #define SharedHandle std::tr1::shared_ptr
// #define WeakHandle std::tr1::weak_ptr
// using std::tr1::static_pointer_cast;
// using std::tr1::dynamic_pointer_cast;
namespace aria2 {
typedef struct StrongRef {} StrongRef;
typedef struct WeakRef {} WeakRef;
class RefCount {
private:
size_t strongRefCount_;
size_t weakRefCount_;
public:
RefCount():strongRefCount_(1), weakRefCount_(1) {}
RefCount(const WeakRef&):strongRefCount_(0), weakRefCount_(1) {}
inline void addRefCount() {
++strongRefCount_;
++weakRefCount_;
}
inline void addWeakRefCount() {
++weakRefCount_;
}
inline void releaseRefCount() {
--strongRefCount_;
--weakRefCount_;
}
inline void releaseWeakRefCount() {
--weakRefCount_;
}
inline size_t getStrongRefCount() { return strongRefCount_; }
inline size_t getWeakRefCount() { return weakRefCount_; }
};
class WeakCount;
class SharedCount {
private:
friend class WeakCount;
RefCount* refCount_;
public:
SharedCount():refCount_(new RefCount()) {}
SharedCount(const SharedCount& s):refCount_(s.refCount_)
{
refCount_->addRefCount();
}
~SharedCount() {
refCount_->releaseRefCount();
if(refCount_->getWeakRefCount() == 0) {
delete refCount_;
}
}
bool reassign(const SharedCount& s) {
s.refCount_->addRefCount();
refCount_->releaseRefCount();
if(refCount_->getWeakRefCount() == 0) {
delete refCount_;
refCount_ = s.refCount_;
return true;
}
size_t thisCount = refCount_->getStrongRefCount();
refCount_ = s.refCount_;
return thisCount == 0;
}
inline size_t getRefCount() const { return refCount_->getStrongRefCount(); }
void swap(SharedCount& r)
{
std::swap(refCount_, r.refCount_);
}
};
class WeakCount {
private:
RefCount* refCount_;
public:
WeakCount(const WeakRef& t):refCount_(new RefCount(t)) {}
WeakCount(const StrongRef& t):refCount_(new RefCount()) {}
WeakCount(const WeakCount& w):refCount_(w.refCount_)
{
refCount_->addWeakRefCount();
}
WeakCount(const SharedCount& s):refCount_(s.refCount_)
{
refCount_->addWeakRefCount();
}
~WeakCount()
{
refCount_->releaseWeakRefCount();
if(refCount_->getWeakRefCount() == 0) {
delete refCount_;
}
}
bool reassign(const SharedCount& s) {
s.refCount_->addWeakRefCount();
refCount_->releaseWeakRefCount();
if(refCount_->getWeakRefCount() == 0) {
delete refCount_;
refCount_ = s.refCount_;
return true;
}
refCount_ = s.refCount_;
return false;
}
bool reassign(const WeakCount& s) {
s.refCount_->addWeakRefCount();
refCount_->releaseWeakRefCount();
if(refCount_->getWeakRefCount() == 0) {
delete refCount_;
refCount_ = s.refCount_;
return true;
}
refCount_ = s.refCount_;
return false;
}
inline size_t getRefCount() const { return refCount_->getStrongRefCount(); }
};
template<typename T>
class SharedHandle;
template<typename T>
class WeakHandle;
template<typename T>
class SharedHandle {
private:
template<typename T1>
friend std::ostream& operator<<(std::ostream& o, const SharedHandle<T1>& sp);
template<typename T1, typename T2>
friend bool operator==(const SharedHandle<T1>& t1,
const SharedHandle<T2>& t2);
template<typename T1, typename T2>
friend bool operator!=(const SharedHandle<T1>& t1,
const SharedHandle<T2>& t2);
template<typename T1, typename T2>
friend bool operator<(const SharedHandle<T1>& t1, const SharedHandle<T2>& t2);
template<typename S> friend class SharedHandle;
template<typename S> friend class WeakHandle;
T* obj_;
SharedCount ucount_;
public:
SharedHandle():obj_(0), ucount_() {}
explicit SharedHandle(T* obj):obj_(obj), ucount_() {}
SharedHandle(const SharedHandle& t):obj_(t.obj_), ucount_(t.ucount_) {}
template<typename S>
SharedHandle(const SharedHandle<S>& t):obj_(t.obj_), ucount_(t.ucount_) {}
template<typename S>
SharedHandle(const SharedHandle<S>& t, T* p):
obj_(p), ucount_(t.ucount_) {}
~SharedHandle() {
if(ucount_.getRefCount() == 1) {
delete obj_;
}
}
SharedHandle& operator=(const SharedHandle& t) {
if(ucount_.reassign(t.ucount_)) {
delete obj_;
}
obj_ = t.obj_;
return *this;
}
template<typename S>
SharedHandle& operator=(const SharedHandle<S>& t) {
if(ucount_.reassign(t.ucount_)) {
delete obj_;
}
obj_ = t.obj_;
return *this;
}
private:
typedef T* SharedHandle::*unspecified_bool_type;
public:
operator unspecified_bool_type() const {
return obj_ == 0 ? 0 : &SharedHandle::obj_;
}
T* operator->() const { return obj_; }
T& operator*() const {
assert(obj_);
return *obj_;
}
T* get() const {
return obj_;
}
size_t getRefCount() const {
return ucount_.getRefCount();
}
void reset() {
*this = SharedHandle();
}
void reset(T* t) {
*this = SharedHandle(t);
}
void swap(SharedHandle& other)
{
std::swap(obj_, other.obj_);
ucount_.swap(other.ucount_);
}
};
template<typename T>
void swap(SharedHandle<T>& a, SharedHandle<T>& b)
{
a.swap(b);
}
template<typename T, typename S>
SharedHandle<T>
dynamic_pointer_cast(const SharedHandle<S>& t) {
if(T* p = dynamic_cast<T*>(t.get())) {
return SharedHandle<T>(t, p);
} else {
return SharedHandle<T>();
}
}
template<typename T, typename S>
SharedHandle<T>
static_pointer_cast(const SharedHandle<S>& t) {
return SharedHandle<T>(t, static_cast<T*>(t.get()));
}
// Intentionally renamed obj_ as obj_x to cause error
template<typename T>
std::ostream& operator<<(std::ostream& o, const SharedHandle<T>& sp) {
o << *sp.obj_x;
return o;
}
template<typename T1, typename T2>
bool operator==(const SharedHandle<T1>& t1, const SharedHandle<T2>& t2) {
return *t1.obj_x == *t2.obj_;
}
template<typename T1, typename T2>
bool operator!=(const SharedHandle<T1>& t1, const SharedHandle<T2>& t2) {
return *t1.obj_x != *t2.obj_;
}
template<typename T1, typename T2>
bool operator<(const SharedHandle<T1>& t1, const SharedHandle<T2>& t2) {
return *t1.obj_x < *t2.obj_;
}
template<typename T>
class WeakHandle {
private:
template<typename T1>
friend std::ostream& operator<<(std::ostream& o, const WeakHandle<T1>& sp);
template<typename T1, typename T2>
friend bool operator==(const WeakHandle<T1>& t1,
const WeakHandle<T2>& t2);
template<typename T1, typename T2>
friend bool operator!=(const WeakHandle<T1>& t1,
const WeakHandle<T2>& t2);
template<typename T1, typename T2>
friend bool operator<(const WeakHandle<T1>& t1, const WeakHandle<T2>& t2);
template<typename S> friend class WeakHandle;
T* obj_;
WeakCount ucount_;
public:
WeakHandle():obj_(0), ucount_(WeakRef()) {}
explicit WeakHandle(T* obj):obj_(obj), ucount_(StrongRef()) {}
WeakHandle(const WeakHandle& t):obj_(t.obj_), ucount_(t.ucount_) {}
template<typename S>
WeakHandle(const SharedHandle<S>& t):obj_(t.obj_), ucount_(t.ucount_) {}
template<typename S>
WeakHandle(const WeakHandle<S>& t, T* p):
obj_(p), ucount_(t.ucount_) {}
~WeakHandle() {}
WeakHandle& operator=(const WeakHandle& t) {
ucount_.reassign(t.ucount_);
obj_ = t.obj_;
return *this;
}
template<typename S>
WeakHandle& operator=(const SharedHandle<S>& t) {
ucount_.reassign(t.ucount_);
obj_ = t.obj_;
return *this;
}
template<typename S>
WeakHandle& operator=(const WeakHandle<S>& t) {
ucount_.reassign(t.ucount_);
obj_ = t.obj_;
return *this;
}
T* operator->() { return obj_; }
T* operator->() const { return obj_; }
T& operator*() const {
assert(obj_);
return *obj_;
}
T* get() const {
if(ucount_.getRefCount() == 0 || obj_ == 0) {
return 0;
} else {
return obj_;
}
}
size_t getRefCount() const {
return ucount_.getRefCount();
}
void reset() {
*this = WeakHandle();
}
};
// Intentionally renamed obj_ as obj_x to cause error
template<typename T>
std::ostream& operator<<(std::ostream& o, const WeakHandle<T>& sp) {
o << *sp.obj_x;
return o;
}
template<typename T1, typename T2>
bool operator==(const WeakHandle<T1>& t1, const WeakHandle<T2>& t2) {
return *t1.obj_x == *t2.obj_;
}
template<typename T1, typename T2>
bool operator!=(const WeakHandle<T1>& t1, const WeakHandle<T2>& t2) {
return *t1.obj_x != *t2.obj_;
}
template<typename T1, typename T2>
bool operator<(const WeakHandle<T1>& t1, const WeakHandle<T2>& t2) {
return *t1.obj_x < *t2.obj_;
}
template<typename T, typename S>
WeakHandle<T>
dynamic_pointer_cast(const WeakHandle<S>& t) {
if(T* p = dynamic_cast<T*>(t.get())) {
return WeakHandle<T>(t, p);
} else {
return WeakHandle<T>();
}
}
} // namespace aria2
#endif // D_SHARED_HANDLE_H