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Diffstat (limited to 'qpid/cpp/src/qpid/sys/ScopedIncrement.h')
-rw-r--r-- | qpid/cpp/src/qpid/sys/ScopedIncrement.h | 67 |
1 files changed, 67 insertions, 0 deletions
diff --git a/qpid/cpp/src/qpid/sys/ScopedIncrement.h b/qpid/cpp/src/qpid/sys/ScopedIncrement.h new file mode 100644 index 0000000000..8645ab2484 --- /dev/null +++ b/qpid/cpp/src/qpid/sys/ScopedIncrement.h @@ -0,0 +1,67 @@ +#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 |