bdlma_deleter.h

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/// @file bdlma_deleter.h
///
/// The content of this file has been pre-processed for Doxygen.
///
 
 
// bdlma_deleter.h                                                    -*-C++-*-
#ifndef INCLUDED_BDLMA_DELETER
#define INCLUDED_BDLMA_DELETER
 
#include <bsls_ident.h>
BSLS_IDENT("$Id: $")
 
/// @defgroup bdlma_deleter bdlma_deleter
/// @brief  Provide a protocol for deleting objects of parameterized type.
/// @addtogroup bdl
/// @{
/// @addtogroup bdlma
/// @{
/// @addtogroup bdlma_deleter
/// @{
///
/// <h1> Outline </h1>
/// * <a href="#bdlma_deleter-purpose"> Purpose</a>
/// * <a href="#bdlma_deleter-classes"> Classes </a>
/// * <a href="#bdlma_deleter-description"> Description </a>
///   * <a href="#bdlma_deleter-usage"> Usage </a>
///     * <a href="#bdlma_deleter-example-1-basic-usage"> Example 1: Basic Usage </a>
///
/// # Purpose {#bdlma_deleter-purpose}
/// Provide a protocol for deleting objects of parameterized type.
///
/// # Classes {#bdlma_deleter-classes}
///
/// -   bdlma::Deleter: protocol class for deleting objects
///
/// @see  bslma_allocator
///
/// # Description {#bdlma_deleter-description}
/// This component defines the base-level protocol,
/// `bdlma::Deleter`, for a thread-safe and type-safe deleter of objects of
/// arbitrary type.  This class is extremely useful for transferring the
/// ownership of objects between different entities.  The following usage
/// example demonstrates this point.
///
/// ## Usage {#bdlma_deleter-usage}
///
///
/// This section illustrates intended use of this component.
///
/// ### Example 1: Basic Usage {#bdlma_deleter-example-1-basic-usage}
///
///
/// Suppose that we would like to transfer ownership of an object between
/// threads using `bsl::shared_ptr`.  For the sake of discussion, the type of
/// this object is `my_Obj`, we will suppose that it is created using a given
/// `basicAllocator`, and that a concrete implementation of `bdlma::Deleter`,
/// say `my_Deleter`, is to be used.  Note that we assume that `my_Obj` does not
/// require an allocator for any of its members:
/// @code
/// bslma::NewDeleteAllocator basicAllocator;
/// my_Obj *object = new(basicAllocator) my_Obj;
/// @endcode
/// Next, create a concrete deleter for `object` using the same allocator as was
/// used to allocate its footprint:
/// @code
/// my_Deleter deleter(&basicAllocator);
/// @endcode
/// Finally, create a shared pointer passing to it `object` and the address of
/// `deleter`:
/// @code
/// bsl::shared_ptr<my_Obj> handle(object, &deleter, &basicAllocator);
/// @endcode
/// Now the `handle` can be passed to another thread or enqueued efficiently.
/// When the reference count of `handle` goes to 0, `object` is automatically
/// deleted via the `deleteObject` method of `deleter`, which in turn will
/// invoke the destructor of `object`.  Note that since the type of the deleter
/// used to instantiate `handle` is `bdlma::Deleter<my_Obj>`, any kind of
/// deleter that implements this protocol can be passed.  Also note, on the
/// downside, that the lifetime of `deleter` must be longer than the lifetime of
/// all associated instances.
/// @}
/** @} */
/** @} */
 
/** @addtogroup bdl
 * @{
 */
/** @addtogroup bdlma
 * @{
 */
/** @addtogroup bdlma_deleter
 * @{
 */
 
#include <bdlscm_version.h>
 
 
namespace bdlma {
 
                              // =============
                              // class Deleter
                              // =============
 
/// Provide a protocol (or pure interface) for a thread-safe object deleter.
///
/// See @ref bdlma_deleter 
template <class TYPE>
class Deleter {
 
  public:
    // CREATORS
 
    /// Destroy this object deleter.
    virtual ~Deleter();
 
    // MANIPULATORS
 
    /// Destroy the specified `instance` based on its static type and return
    /// its memory footprint to the appropriate memory manager.  Note that a
    /// particular implementation is allowed to destroy this deleter itself.
    virtual void deleteObject(TYPE *instance) = 0;
};
 
// ============================================================================
//                             INLINE DEFINITIONS
// ============================================================================
 
// CREATORS
template <class TYPE>
Deleter<TYPE>::~Deleter()
{
}
 
}  // close package namespace
 
 
#endif
 
// ----------------------------------------------------------------------------
// Copyright 2015 Bloomberg Finance L.P.
//
// 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.
// ----------------------------- END-OF-FILE ----------------------------------
 
/** @} */
/** @} */
/** @} */