proton-c/bindings/cpp/include/proton/message_id.hpp

#ifndef MESSAGE_ID_HPP
#define MESSAGE_ID_HPP

/*
 * 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 "proton/types.hpp"
#include "proton/scalar.hpp"

namespace proton {
    
class encoder;
class decoder;

/// An AMQP message ID.
///    
/// It can contain one of the following types:
///
///  - uint64_t
///  - proton::amqp::amqp_uuid
///  - proton::amqp::amqp_binary
///  - proton::amqp::amqp_string
class message_id : public restricted_scalar {
  public:
    /// Create an empty (0) message ID.
    message_id() { scalar_ = uint64_t(0); }

    /// @name Assignment operators
    ///
    /// Assign a C++ value, deduce the AMQP type()
    ///
    /// @{
    message_id& operator=(uint64_t x) { scalar_ = x; return *this; }
    message_id& operator=(const amqp_uuid& x) { scalar_ = x; return *this; }
    message_id& operator=(const amqp_binary& x) { scalar_ = x; return *this; }
    message_id& operator=(const amqp_string& x) { scalar_ = x; return *this; }
    /// std::string is encoded as amqp_string
    message_id& operator=(const std::string& x) { scalar_ = amqp_string(x); return *this; }
    /// char* is encoded as amqp_string
    message_id& operator=(const char *x) { scalar_ = amqp_string(x); return *this; }
    /// @}

    /// Create a message ID from any type that we can assign from.
    template <class T> message_id(T x) { *this = x; }

    /// @name Get methods
    ///
    /// get(T&) extracts the value if the types match exactly and
    /// throws type_error otherwise.
    ///
    /// @{
    void get(uint64_t& x) const { scalar_.get(x); }
    void get(amqp_uuid& x) const { scalar_.get(x); }
    void get(amqp_binary& x) const { scalar_.get(x); }
    void get(amqp_string& x) const { scalar_.get(x); }
    /// @}

    /// Return the value as type T.
    template<class T> T get() const { T x; get(x); return x; }

    /// @cond INTERNAL
    friend PN_CPP_EXTERN encoder operator<<(encoder, const message_id&);
    friend PN_CPP_EXTERN decoder operator>>(decoder, message_id&);
    friend class message;
    /// @endcond
};

}
#endif // MESSAGE_ID_HPP