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Diffstat (limited to 'qpid/cpp/src/qpid/messaging/PrivateImplRef.h')
-rw-r--r-- | qpid/cpp/src/qpid/messaging/PrivateImplRef.h | 94 |
1 files changed, 94 insertions, 0 deletions
diff --git a/qpid/cpp/src/qpid/messaging/PrivateImplRef.h b/qpid/cpp/src/qpid/messaging/PrivateImplRef.h new file mode 100644 index 0000000000..e77c58d071 --- /dev/null +++ b/qpid/cpp/src/qpid/messaging/PrivateImplRef.h @@ -0,0 +1,94 @@ +#ifndef QPID_MESSAGING_PRIVATEIMPL_H +#define QPID_MESSAGING_PRIVATEIMPL_H + +/* + * + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you 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 "qpid/messaging/ImportExport.h" +#include <boost/intrusive_ptr.hpp> +#include "qpid/RefCounted.h" + +namespace qpid { +namespace messaging { + +/** + * Helper class to implement a class with a private, reference counted + * implementation and reference semantics. + * + * Such classes are used in the public API to hide implementation, they + * should. Example of use: + * + * === Foo.h + * + * template <class T> PrivateImplRef; + * class FooImpl; + * + * Foo : public Handle<FooImpl> { + * public: + * Foo(FooImpl* = 0); + * Foo(const Foo&); + * ~Foo(); + * Foo& operator=(const Foo&); + * + * int fooDo(); // and other Foo functions... + * + * private: + * typedef FooImpl Impl; + * Impl* impl; + * friend class PrivateImplRef<Foo>; + * + * === Foo.cpp + * + * typedef PrivateImplRef<Foo> PI; + * Foo::Foo(FooImpl* p) { PI::ctor(*this, p); } + * Foo::Foo(const Foo& c) : Handle<FooImpl>() { PI::copy(*this, c); } + * Foo::~Foo() { PI::dtor(*this); } + * Foo& Foo::operator=(const Foo& c) { return PI::assign(*this, c); } + * + * int foo::fooDo() { return impl->fooDo(); } + * + */ +template <class T> class PrivateImplRef { + public: + typedef typename T::Impl Impl; + typedef boost::intrusive_ptr<Impl> intrusive_ptr; + + /** Get the implementation pointer from a handle */ + static intrusive_ptr get(const T& t) { return intrusive_ptr(t.impl); } + + /** Set the implementation pointer in a handle */ + static void set(T& t, const intrusive_ptr& p) { + if (t.impl == p) return; + if (t.impl) boost::intrusive_ptr_release(t.impl); + t.impl = p.get(); + if (t.impl) boost::intrusive_ptr_add_ref(t.impl); + } + + // Helper functions to implement the ctor, dtor, copy, assign + static void ctor(T& t, Impl* p) { t.impl = p; if (p) boost::intrusive_ptr_add_ref(p); } + static void copy(T& t, const T& x) { if (&t == &x) return; t.impl = 0; assign(t, x); } + static void dtor(T& t) { if(t.impl) boost::intrusive_ptr_release(t.impl); } + static T& assign(T& t, const T& x) { set(t, get(x)); return t;} +}; + +}} // namespace qpid::messaging + +#endif /*!QPID_MESSAGING_PRIVATEIMPL_H*/ |