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DEFINITIONS
This source file includes following definitions.
- Q_DBG
- queue_destroy
- APU_DECLARE
- APU_DECLARE
- APU_DECLARE
- APU_DECLARE
- APU_DECLARE
- APU_DECLARE
- APU_DECLARE
- APU_DECLARE
/* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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 "apr.h"
#if APR_HAVE_STDIO_H
#include <stdio.h>
#endif
#if APR_HAVE_STDLIB_H
#include <stdlib.h>
#endif
#if APR_HAVE_UNISTD_H
#include <unistd.h>
#endif
#include "apu.h"
#include "apr_portable.h"
#include "apr_thread_mutex.h"
#include "apr_thread_cond.h"
#include "apr_errno.h"
#include "apr_queue.h"
#if APR_HAS_THREADS
/*
* define this to get debug messages
*
#define QUEUE_DEBUG
*/
struct apr_queue_t {
void **data;
unsigned int nelts; /**< # elements */
unsigned int in; /**< next empty location */
unsigned int out; /**< next filled location */
unsigned int bounds;/**< max size of queue */
unsigned int full_waiters;
unsigned int empty_waiters;
apr_thread_mutex_t *one_big_mutex;
apr_thread_cond_t *not_empty;
apr_thread_cond_t *not_full;
int terminated;
};
#ifdef QUEUE_DEBUG
static void Q_DBG(char*msg, apr_queue_t *q) {
fprintf(stderr, "%ld\t#%d in %d out %d\t%s\n",
apr_os_thread_current(),
q->nelts, q->in, q->out,
msg
);
}
#else
#define Q_DBG(x,y)
#endif
/**
* Detects when the apr_queue_t is full. This utility function is expected
* to be called from within critical sections, and is not threadsafe.
*/
#define apr_queue_full(queue) ((queue)->nelts == (queue)->bounds)
/**
* Detects when the apr_queue_t is empty. This utility function is expected
* to be called from within critical sections, and is not threadsafe.
*/
#define apr_queue_empty(queue) ((queue)->nelts == 0)
/**
* Callback routine that is called to destroy this
* apr_queue_t when its pool is destroyed.
*/
static apr_status_t queue_destroy(void *data)
{
apr_queue_t *queue = data;
/* Ignore errors here, we can't do anything about them anyway. */
apr_thread_cond_destroy(queue->not_empty);
apr_thread_cond_destroy(queue->not_full);
apr_thread_mutex_destroy(queue->one_big_mutex);
return APR_SUCCESS;
}
/**
* Initialize the apr_queue_t.
*/
APU_DECLARE(apr_status_t) apr_queue_create(apr_queue_t **q,
unsigned int queue_capacity,
apr_pool_t *a)
{
apr_status_t rv;
apr_queue_t *queue;
queue = apr_palloc(a, sizeof(apr_queue_t));
*q = queue;
/* nested doesn't work ;( */
rv = apr_thread_mutex_create(&queue->one_big_mutex,
APR_THREAD_MUTEX_UNNESTED,
a);
if (rv != APR_SUCCESS) {
return rv;
}
rv = apr_thread_cond_create(&queue->not_empty, a);
if (rv != APR_SUCCESS) {
return rv;
}
rv = apr_thread_cond_create(&queue->not_full, a);
if (rv != APR_SUCCESS) {
return rv;
}
/* Set all the data in the queue to NULL */
queue->data = apr_pcalloc(a, queue_capacity * sizeof(void*));
queue->bounds = queue_capacity;
queue->nelts = 0;
queue->in = 0;
queue->out = 0;
queue->terminated = 0;
queue->full_waiters = 0;
queue->empty_waiters = 0;
apr_pool_cleanup_register(a, queue, queue_destroy, apr_pool_cleanup_null);
return APR_SUCCESS;
}
/**
* Push new data onto the queue. Blocks if the queue is full. Once
* the push operation has completed, it signals other threads waiting
* in apr_queue_pop() that they may continue consuming sockets.
*/
APU_DECLARE(apr_status_t) apr_queue_push(apr_queue_t *queue, void *data)
{
apr_status_t rv;
if (queue->terminated) {
return APR_EOF; /* no more elements ever again */
}
rv = apr_thread_mutex_lock(queue->one_big_mutex);
if (rv != APR_SUCCESS) {
return rv;
}
if (apr_queue_full(queue)) {
if (!queue->terminated) {
queue->full_waiters++;
rv = apr_thread_cond_wait(queue->not_full, queue->one_big_mutex);
queue->full_waiters--;
if (rv != APR_SUCCESS) {
apr_thread_mutex_unlock(queue->one_big_mutex);
return rv;
}
}
/* If we wake up and it's still empty, then we were interrupted */
if (apr_queue_full(queue)) {
Q_DBG("queue full (intr)", queue);
rv = apr_thread_mutex_unlock(queue->one_big_mutex);
if (rv != APR_SUCCESS) {
return rv;
}
if (queue->terminated) {
return APR_EOF; /* no more elements ever again */
}
else {
return APR_EINTR;
}
}
}
queue->data[queue->in] = data;
queue->in = (queue->in + 1) % queue->bounds;
queue->nelts++;
if (queue->empty_waiters) {
Q_DBG("sig !empty", queue);
rv = apr_thread_cond_signal(queue->not_empty);
if (rv != APR_SUCCESS) {
apr_thread_mutex_unlock(queue->one_big_mutex);
return rv;
}
}
rv = apr_thread_mutex_unlock(queue->one_big_mutex);
return rv;
}
/**
* Push new data onto the queue. Blocks if the queue is full. Once
* the push operation has completed, it signals other threads waiting
* in apr_queue_pop() that they may continue consuming sockets.
*/
APU_DECLARE(apr_status_t) apr_queue_trypush(apr_queue_t *queue, void *data)
{
apr_status_t rv;
if (queue->terminated) {
return APR_EOF; /* no more elements ever again */
}
rv = apr_thread_mutex_lock(queue->one_big_mutex);
if (rv != APR_SUCCESS) {
return rv;
}
if (apr_queue_full(queue)) {
rv = apr_thread_mutex_unlock(queue->one_big_mutex);
return APR_EAGAIN;
}
queue->data[queue->in] = data;
queue->in = (queue->in + 1) % queue->bounds;
queue->nelts++;
if (queue->empty_waiters) {
Q_DBG("sig !empty", queue);
rv = apr_thread_cond_signal(queue->not_empty);
if (rv != APR_SUCCESS) {
apr_thread_mutex_unlock(queue->one_big_mutex);
return rv;
}
}
rv = apr_thread_mutex_unlock(queue->one_big_mutex);
return rv;
}
/**
* not thread safe
*/
APU_DECLARE(unsigned int) apr_queue_size(apr_queue_t *queue) {
return queue->nelts;
}
/**
* Retrieves the next item from the queue. If there are no
* items available, it will block until one becomes available.
* Once retrieved, the item is placed into the address specified by
* 'data'.
*/
APU_DECLARE(apr_status_t) apr_queue_pop(apr_queue_t *queue, void **data)
{
apr_status_t rv;
if (queue->terminated) {
return APR_EOF; /* no more elements ever again */
}
rv = apr_thread_mutex_lock(queue->one_big_mutex);
if (rv != APR_SUCCESS) {
return rv;
}
/* Keep waiting until we wake up and find that the queue is not empty. */
if (apr_queue_empty(queue)) {
if (!queue->terminated) {
queue->empty_waiters++;
rv = apr_thread_cond_wait(queue->not_empty, queue->one_big_mutex);
queue->empty_waiters--;
if (rv != APR_SUCCESS) {
apr_thread_mutex_unlock(queue->one_big_mutex);
return rv;
}
}
/* If we wake up and it's still empty, then we were interrupted */
if (apr_queue_empty(queue)) {
Q_DBG("queue empty (intr)", queue);
rv = apr_thread_mutex_unlock(queue->one_big_mutex);
if (rv != APR_SUCCESS) {
return rv;
}
if (queue->terminated) {
return APR_EOF; /* no more elements ever again */
}
else {
return APR_EINTR;
}
}
}
*data = queue->data[queue->out];
queue->nelts--;
queue->out = (queue->out + 1) % queue->bounds;
if (queue->full_waiters) {
Q_DBG("signal !full", queue);
rv = apr_thread_cond_signal(queue->not_full);
if (rv != APR_SUCCESS) {
apr_thread_mutex_unlock(queue->one_big_mutex);
return rv;
}
}
rv = apr_thread_mutex_unlock(queue->one_big_mutex);
return rv;
}
/**
* Retrieves the next item from the queue. If there are no
* items available, return APR_EAGAIN. Once retrieved,
* the item is placed into the address specified by 'data'.
*/
APU_DECLARE(apr_status_t) apr_queue_trypop(apr_queue_t *queue, void **data)
{
apr_status_t rv;
if (queue->terminated) {
return APR_EOF; /* no more elements ever again */
}
rv = apr_thread_mutex_lock(queue->one_big_mutex);
if (rv != APR_SUCCESS) {
return rv;
}
if (apr_queue_empty(queue)) {
rv = apr_thread_mutex_unlock(queue->one_big_mutex);
return APR_EAGAIN;
}
*data = queue->data[queue->out];
queue->nelts--;
queue->out = (queue->out + 1) % queue->bounds;
if (queue->full_waiters) {
Q_DBG("signal !full", queue);
rv = apr_thread_cond_signal(queue->not_full);
if (rv != APR_SUCCESS) {
apr_thread_mutex_unlock(queue->one_big_mutex);
return rv;
}
}
rv = apr_thread_mutex_unlock(queue->one_big_mutex);
return rv;
}
APU_DECLARE(apr_status_t) apr_queue_interrupt_all(apr_queue_t *queue)
{
apr_status_t rv;
Q_DBG("intr all", queue);
if ((rv = apr_thread_mutex_lock(queue->one_big_mutex)) != APR_SUCCESS) {
return rv;
}
apr_thread_cond_broadcast(queue->not_empty);
apr_thread_cond_broadcast(queue->not_full);
if ((rv = apr_thread_mutex_unlock(queue->one_big_mutex)) != APR_SUCCESS) {
return rv;
}
return APR_SUCCESS;
}
APU_DECLARE(apr_status_t) apr_queue_term(apr_queue_t *queue)
{
apr_status_t rv;
if ((rv = apr_thread_mutex_lock(queue->one_big_mutex)) != APR_SUCCESS) {
return rv;
}
/* we must hold one_big_mutex when setting this... otherwise,
* we could end up setting it and waking everybody up just after a
* would-be popper checks it but right before they block
*/
queue->terminated = 1;
if ((rv = apr_thread_mutex_unlock(queue->one_big_mutex)) != APR_SUCCESS) {
return rv;
}
return apr_queue_interrupt_all(queue);
}
#endif /* APR_HAS_THREADS */