/*
 * Copyright 2004,2005 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.
 */

#ifndef AXIS2_THREAD_H
#define AXIS2_THREAD_H


/**
  * @file axis2_thread.h
  * @brief axis2 thread api
  */

#include <axis2_allocator.h>
#include <axis2_utils_defines.h>
#include <axis2_error.h>


#ifdef __cplusplus
extern "C"
{
#endif

/**
 * @defgroup axis2_thread thread
 * @ingroup axis2_util
 * @{
 */
   
/**
 * Thread callbacks from axis2 functions must be declared with AXIS2_THREAD_FUNC
 * so that they follow the platform's calling convention.
 */
/*#define AXIS2_THREAD_FUNC*/
   
/** Thread structure. */
typedef struct axis2_thread_t           axis2_thread_t;

/** Thread attributes structure. */
typedef struct axis2_threadattr_t       axis2_threadattr_t;

/** Control variable for one-time atomic variables.  */
typedef struct axis2_thread_once_t      axis2_thread_once_t;

/**
 * The prototype for any AXIS2 thread worker functions.
 */
typedef void *(AXIS2_THREAD_FUNC *axis2_thread_start_t)(axis2_thread_t*, void*);

/** Thread private address space. */
typedef struct axis2_threadkey_t        axis2_threadkey_t;

/* Thread Function definitions */

/**
 * Create and initialize a new threadattr variable
 * @param cont The pool to use
 * @return Newly created thread attribute
 */
AXIS2_EXTERN axis2_threadattr_t* AXIS2_CALL 
axis2_threadattr_create(axis2_allocator_t *allocator);

/**
 * Set if newly created threads should be created in detached state.
 * @param attr The threadattr to affect
 * @param on Non-zero if detached threads should be created.
 * @return The status of the operation
 */
AXIS2_EXTERN axis2_status_t AXIS2_CALL
axis2_threadattr_detach_set(axis2_threadattr_t *attr, axis2_bool_t detached);

/**
 * Get the detach state for this threadattr.
 * @param attr The threadattr to reference
 * @return AXIS2_TRUE if threads are to be detached, or AXIS2_FALSE
 * if threads are to be joinable.
 */
AXIS2_EXTERN axis2_bool_t AXIS2_CALL
axis2_threadattr_is_detach(axis2_threadattr_t *attr, axis2_allocator_t *allocator);


/**
 * Create a new thread of execution
 * @param attr The threadattr to use to determine how to create the thread
 * @param func The function to start the new thread in
 * @param data Any data to be passed to the starting function
 * @param cont The pool to use
 * @return The newly created thread handle.
 */
AXIS2_EXTERN axis2_thread_t* AXIS2_CALL 
axis2_thread_create(axis2_allocator_t *allocator, axis2_threadattr_t *attr,
                        axis2_thread_start_t func, void *data);

/**
 * Stop the current thread
 * @param thd The thread to stop
 * @return The status of the operation
 */
AXIS2_EXTERN axis2_status_t AXIS2_CALL 
axis2_thread_exit(axis2_thread_t *thd, axis2_allocator_t *allocator);

/**
 * Block until the desired thread stops executing.
 * @param thd The thread to join
 * @return The status of the operation
 */
AXIS2_EXTERN axis2_status_t AXIS2_CALL 
axis2_thread_join(axis2_thread_t *thd);

/**
 * force the current thread to yield the processor
 */
AXIS2_EXTERN void AXIS2_CALL 
axis2_thread_yield();

/**
 * Initialize the control variable for axis2_thread_once.
 * @param control The control variable to initialize
 * @return The status of the operation
 */
AXIS2_EXTERN axis2_thread_once_t* AXIS2_CALL 
axis2_thread_once_init(axis2_allocator_t *allocator);

/**
 * Run the specified function one time, regardless of how many threads
 * call it.
 * @param control The control variable.  The same variable should
 *                be passed in each time the function is tried to be
 *                called.  This is how the underlying functions determine
 *                if the function has ever been called before.
 * @param func The function to call.
 * @return The status of the operation
 */
AXIS2_EXTERN axis2_status_t AXIS2_CALL
axis2_thread_once(axis2_thread_once_t *control, void (*func)(void));

/**
 * detach a thread
 * @param thd The thread to detach
 * @return The status of the operation
 */
AXIS2_EXTERN axis2_status_t AXIS2_CALL 
axis2_thread_detach(axis2_thread_t *thd);

/*************************Thread locking functions*****************************/

/** Opaque thread-local mutex structure */
typedef struct axis2_thread_mutex_t axis2_thread_mutex_t;

#define AXIS2_THREAD_MUTEX_DEFAULT  0x0   /**< platform-optimal lock behavior */
#define AXIS2_THREAD_MUTEX_NESTED   0x1   /**< enable nested (recursive) locks */
#define AXIS2_THREAD_MUTEX_UNNESTED 0x2   /**< disable nested locks */

/**
 * Create and initialize a mutex that can be used to synchronize threads.
 * @param allocator Memory allocator to allocate memory for the mutex
 * @warning Be cautious in using AXIS2_THREAD_MUTEX_DEFAULT.  While this is the
 * most optimial mutex based on a given platform's performance charateristics,
 * it will behave as either a nested or an unnested lock.
 */
AXIS2_EXTERN axis2_thread_mutex_t * AXIS2_CALL
axis2_thread_mutex_create(axis2_allocator_t *allocator, unsigned int flags);
/**
 * Acquire the lock for the given mutex. If the mutex is already locked,
 * the current thread will be put to sleep until the lock becomes available.
 * @param mutex the mutex on which to acquire the lock.
 */
AXIS2_EXTERN axis2_status_t AXIS2_CALL 
axis2_thread_mutex_lock(axis2_thread_mutex_t *mutex);

/**
 * Attempt to acquire the lock for the given mutex. If the mutex has already
 * been acquired, the call returns immediately 
 * @param mutex the mutex on which to attempt the lock acquiring.
 */
AXIS2_EXTERN axis2_status_t AXIS2_CALL 
axis2_thread_mutex_trylock(axis2_thread_mutex_t *mutex);

/**
 * Release the lock for the given mutex.
 * @param mutex the mutex from which to release the lock.
 */
AXIS2_EXTERN axis2_status_t AXIS2_CALL 
axis2_thread_mutex_unlock(axis2_thread_mutex_t *mutex);

/**
 * Destroy the mutex and free the memory associated with the lock.
 * @param mutex the mutex to destroy.
 */
AXIS2_EXTERN axis2_status_t AXIS2_CALL
axis2_thread_mutex_destroy(axis2_thread_mutex_t *mutex);

/** @} */
#ifdef __cplusplus
}
#endif

#endif                          /* AXIS2_THREAD_H */