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#ifndef _posix_ScopedIncrement_h
#define _posix_ScopedIncrement_h
/*
*
* Copyright (c) 2006 The Apache Software Foundation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
#include <boost/noncopyable.hpp>
#include <boost/function.hpp>
namespace qpid {
namespace sys {
/**
* Increment counter in constructor and decrement in destructor.
* Optionally call a function if the decremented counter value is 0.
* Note the function must not throw, it is called in the destructor.
*/
template <class T, class F=boost::function<void()> >
class ScopedIncrement : boost::noncopyable
{
public:
ScopedIncrement(T& c, F f=0)
: count(c), callback(f) { ++count; }
~ScopedIncrement() { if (--count == 0 && callback) callback(); }
private:
T& count;
F callback;
};
/** Decrement counter in constructor and increment in destructor. */
template <class T>
class ScopedDecrement : boost::noncopyable
{
public:
ScopedDecrement(T& c) : count(c) { value = --count; }
~ScopedDecrement() { ++count; }
/** Return the value after the decrement. */
operator long() { return value; }
private:
T& count;
long value;
};
}}
#endif // _posix_ScopedIncrement_h
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