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#ifndef AWS_COMMON_REF_COUNT_H
#define AWS_COMMON_REF_COUNT_H
/**
* Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
* SPDX-License-Identifier: Apache-2.0.
*/
#include <aws/common/common.h>
#include <aws/common/atomics.h>
#include <aws/common/shutdown_types.h>
AWS_PUSH_SANE_WARNING_LEVEL
/*
* A utility type for making ref-counted types, reminiscent of std::shared_ptr in C++
*/
struct aws_ref_count {
struct aws_atomic_var ref_count;
void *object;
aws_simple_completion_callback *on_zero_fn;
};
AWS_EXTERN_C_BEGIN
/**
* Initializes a ref-counter structure. After initialization, the ref count will be 1.
*
* @param ref_count ref-counter to initialize
* @param object object being ref counted
* @param on_zero_fn function to invoke when the ref count reaches zero
*/
AWS_COMMON_API void aws_ref_count_init(
struct aws_ref_count *ref_count,
void *object,
aws_simple_completion_callback *on_zero_fn);
/**
* Increments a ref-counter's ref count
*
* @param ref_count ref-counter to increment the count for
* @return the object being ref-counted
*/
AWS_COMMON_API void *aws_ref_count_acquire(struct aws_ref_count *ref_count);
/**
* Decrements a ref-counter's ref count. Invokes the on_zero callback if the ref count drops to zero
* @param ref_count ref-counter to decrement the count for
* @return the value of the decremented ref count
*/
AWS_COMMON_API size_t aws_ref_count_release(struct aws_ref_count *ref_count);
AWS_EXTERN_C_END
AWS_POP_SANE_WARNING_LEVEL
#endif /* AWS_COMMON_REF_COUNT_H */
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