/*
 * Copyright 2008-2019 Aerospike, Inc.
 *
 * Portions may be licensed to Aerospike, Inc. under one or more contributor
 * license agreements.
 *
 * 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.
 */
#include <aerospike/as_queue_mt.h>
#include <citrusleaf/cf_clock.h>
#include <citrusleaf/alloc.h>

#define ITEMS_ON_HEAP 1
#define ALL_ON_HEAP 2

/******************************************************************************
 * STATIC FUNCTIONS
 ******************************************************************************/

static void as_queue_mt_wait(as_queue_mt *queue, int wait_ms)
{
    // as_queue_empty() is checked in as_queue_pop(), so no need
    // to check here on AS_QUEUE_NOWAIT.
    if (wait_ms == AS_QUEUE_NOWAIT || !as_queue_empty(&queue->queue)) {
        return;
    }

    if (wait_ms == AS_QUEUE_FOREVER) {
        // Note that we have to use a while() loop. The pthread_cond_signal()
        // documentation says that AT LEAST ONE waiting thread will be awakened.
        // If more than one are awakened, the first will get the popped element,
        // others will find the queue empty and go back to waiting.
        do {
            pthread_cond_wait(&queue->cond, &queue->lock);
        } while (as_queue_empty(&queue->queue));

        return;
    }

    struct timespec tp;
    cf_set_wait_timespec(wait_ms, &tp);
    pthread_cond_timedwait(&queue->cond, &queue->lock, &tp);
}

/******************************************************************************
 * FUNCTIONS
 ******************************************************************************/

bool as_queue_mt_init(as_queue_mt *queue, uint32_t item_size, uint32_t capacity)
{
    if (!as_queue_init(&queue->queue, item_size, capacity)) {
        return false;
    }

    if (pthread_mutex_init(&queue->lock, NULL) != 0) {
        as_queue_destroy(&queue->queue);
        return false;
    }

    if (pthread_cond_init(&queue->cond, NULL) != 0) {
        pthread_mutex_destroy(&queue->lock);
        as_queue_destroy(&queue->queue);
        return false;
    }
    return true;
}

as_queue_mt *as_queue_mt_create(uint32_t item_size, uint32_t capacity)
{
    as_queue_mt *queue = cf_malloc(sizeof(as_queue_mt));

    if (!queue) {
        return NULL;
    }

    if (!as_queue_mt_init(queue, item_size, capacity)) {
        cf_free(queue);
        return NULL;
    }
    queue->queue.flags = ITEMS_ON_HEAP | ALL_ON_HEAP;
    return queue;
}

bool as_queue_mt_pop(as_queue_mt *queue, void *ptr, int wait_ms)
{
    pthread_mutex_lock(&queue->lock);
    as_queue_mt_wait(queue, wait_ms);
    bool status = as_queue_pop(&queue->queue, ptr);
    pthread_mutex_unlock(&queue->lock);
    return status;
}

bool as_queue_mt_pop_tail(as_queue_mt *queue, void *ptr, int wait_ms)
{
    pthread_mutex_lock(&queue->lock);
    as_queue_mt_wait(queue, wait_ms);
    bool status = as_queue_pop_tail(&queue->queue, ptr);
    pthread_mutex_unlock(&queue->lock);
    return status;
}
