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-rw-r--r--misc/apr_queue.c398
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diff --git a/misc/apr_queue.c b/misc/apr_queue.c
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+/* 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++;
+ if (queue->in >= queue->bounds)
+ queue->in -= 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. If the queue is full, return APR_EAGAIN. If
+ * the push operation completes successfully, 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++;
+ if (queue->in >= queue->bounds)
+ queue->in -= 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++;
+ if (queue->out >= queue->bounds)
+ queue->out -= 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++;
+ if (queue->out >= queue->bounds)
+ queue->out -= 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 */