/* -*- Mode: C; c-basic-offset:4 ; indent-tabs-mode:nil -*- */
/*
 * Copyright (c) 2007-2013 Los Alamos National Security, LLC.  All rights
 *                         reserved.
 * Copyright (c) 2008      Cisco Systems, Inc.  All rights reserved.
 * Copyright (c) 2015-2017 Research Organization for Information Science
 *                         and Technology (RIST). All rights reserved.
 * Copyright (c) 2019      Sandia National Laboratories. All rights reserved.
 *
 * $COPYRIGHT$
 *
 * Additional copyrights may follow
 *
 * $HEADER$
 */

#ifndef OPAL_MCA_THREADS_TSD_H
#define OPAL_MCA_THREADS_TSD_H

#include "opal_config.h"

#include <pthread.h>

#include "mutex.h"
#include "opal/class/opal_list.h"
#include "opal/constants.h"

BEGIN_C_DECLS

/**
 * @file
 *
 * Thread Specific Datastore Interface
 *
 * Functions for providing thread-specific datastore capabilities.
 */

/**
 * Prototype for callback when tsd data is being destroyed
 */
typedef void (*opal_tsd_destructor_t)(void *value);

#if defined(DOXYGEN)

/**
 * Typedef for thread-specific data key
 */
typedef void *opal_tsd_key_t;

/**
 * Delete a thread-specific data key
 *
 * Delete a thread-specific data key previously returned by
 * opal_tsd_key_create().  The destructor associated with the key is
 * not fired in any thread and memory cleanup is the responsibility of
 * the caller.
 *
 * @note Unlike pthread_key_delete, this function should not be called
 * from within a destructor.  It can not be universally supported at
 * this time.
 *
 * @param key[in]       The key for accessing thread-specific data
 *
 * @retval OPAL_SUCCESS      Success
 * @retval OPAL_ERROR        Error
 * @retval OPAL_ERR_IN_ERRNO Error
 */
OPAL_DECLSPEC int opal_tsd_key_delete(opal_tsd_key_t key);

/**
 * Set a thread-specific data value
 *
 * Associates value with key in the current thread.  The value for the
 * key in other threads is not changed.  Different threads may assign
 * different values to the same key.
 *
 * @note This function should not be called within
 * opal_tsd_key_delete().
 *
 * @param key[in]       Thread specific data key to modify
 * @param value[in]     Value to associate with key
 *
 * @retval OPAL_SUCCESS      Success
 * @retval OPAL_ERR          Error
 * @retval OPAL_ERR_IN_ERRNO Error
 */
OPAL_DECLSPEC int opal_tsd_setspecific(opal_tsd_key_t key, void *value);

/**
 * Get a thread-specific data value
 *
 * Get the data associated with the given key, as set by
 * opal_tsd_setspecific().  If opal_tsd_setspecific() hasn't been
 * called in the current thread with the given key, NULL is returned
 * in valuep.
 *
 * @param key[in]        Thread specific data key to modify
 * @param value[out]     Value to associate with key
 *
 * @retval OPAL_SUCCESS      Success
 * @retval OPAL_ERR          Error
 * @retval OPAL_ERR_IN_ERRNO Error
 */
OPAL_DECLSPEC int opal_tsd_getspecific(opal_tsd_key_t key, void **valuep);

#else

#    include MCA_threads_tsd_base_include_HEADER

#endif

typedef struct opal_tsd_tracked_key_s opal_tsd_tracked_key_t;

typedef struct _opal_tsd_list_item_t {
    opal_list_item_t super;
    opal_tsd_tracked_key_t *tracked_key;
    void *data;
} opal_tsd_list_item_t;
OBJ_CLASS_DECLARATION(opal_tsd_list_item_t);

struct opal_tsd_tracked_key_s {
    opal_object_t super;
    opal_tsd_key_t key;
    opal_mutex_t mutex;
    opal_list_t tsd_list;
    void (*user_destructor)(void *);
};
OBJ_CLASS_DECLARATION(opal_tsd_tracked_key_t);

void opal_tsd_tracked_key_constructor(opal_tsd_tracked_key_t *key);
void opal_tsd_tracked_key_destructor(opal_tsd_tracked_key_t *key);

static inline int opal_tsd_tracked_key_get(opal_tsd_tracked_key_t *key, void **p)
{
    assert(NULL != key);
    *p = NULL;

    opal_tsd_list_item_t *tsd = NULL;
    opal_tsd_get(key->key, (void **) &tsd);
    if (NULL != tsd) {
        *p = tsd->data;
    }

    return OPAL_SUCCESS;
}

OPAL_DECLSPEC int opal_tsd_tracked_key_set(opal_tsd_tracked_key_t *key, void *p);
OPAL_DECLSPEC void opal_tsd_tracked_key_set_destructor(opal_tsd_tracked_key_t *key,
                                                       opal_tsd_destructor_t destructor);

/**
 * Create thread-specific data key
 *
 * Create a thread-specific data key visible to all threads in the
 * current process.  The returned key is valid in all threads,
 * although the values bound to the key by opal_tsd_setspecific() are
 * allocated on a per-thread basis and persist for the life of the
 * calling thread.
 *
 * Upon key creation, the value NULL is associated with the new key in
 * all active threads.  When a new thread is created, the value NULL
 * is associated with all defined keys in the new thread.
 *
 * The destructor parameter may be NULL.  At thread exit, if
 * destructor is non-NULL AND the thread has a non-NULL value
 * associated with the key, the function is called with the current
 * value as its argument.
 *
 * @param key[out]       The key for accessing thread-specific data
 * @param destructor[in] Cleanup function to call when a thread exits
 *
 * @retval OPAL_SUCCESS      Success
 * @retval OPAL_ERR          Error
 * @retval OPAL_ERR_IN_ERRNO Error
 */
OPAL_DECLSPEC int opal_tsd_key_create(opal_tsd_key_t *key, opal_tsd_destructor_t destructor);

END_C_DECLS

#endif /* OPAL_MCA_THREADS_TSD_H */