From 05266ad52ef0c1848a81b21705b9f13fc8f7028b Mon Sep 17 00:00:00 2001
From: Anthony Minessale <anthm@freeswitch.org>
Date: Fri, 14 Mar 2014 01:35:26 +0500
Subject: [PATCH 8/8] Add apr_queue_pop_timeout()

This function will pop or get an object from the queue, blocking if
the queue is already empty for up to N microseconds.

Signed-off-by: Anthony Minessale <anthm@freeswitch.org>
Signed-off-by: Travis Cross <tc@traviscross.com>
---
 include/apr_queue.h   | 18 +++++++++++++++
 util-misc/apr_queue.c | 64 +++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 82 insertions(+)

diff --git a/include/apr_queue.h b/include/apr_queue.h
index 1d09e9d..e7544d6 100644
--- a/include/apr_queue.h
+++ b/include/apr_queue.h
@@ -25,9 +25,11 @@
  * Although condition variables are sometimes available without threads.
  */
 
+#include "apr.h"
 #include "apu.h"
 #include "apr_errno.h"
 #include "apr_pools.h"
+#include "apr_time.h"
 
 #if APR_HAS_THREADS
 
@@ -79,6 +81,22 @@ APR_DECLARE(apr_status_t) apr_queue_push(apr_queue_t *queue, void *data);
 APR_DECLARE(apr_status_t) apr_queue_pop(apr_queue_t *queue, void **data);
 
 /**
+ * pop/get an object from the queue, blocking if the queue is already empty for up to N microseconds
+ *
+ * @param queue the queue
+ * @param data the data
+ * @param timeout The amount of time in microseconds to wait. This is
+ *        a maximum, not a minimum. If the condition is signaled, we
+ *        will wake up before this time, otherwise the error APR_TIMEUP
+ *        is returned.
+ * @returns APR_TIMEUP the request timed out
+ * @returns APR_EINTR the blocking was interrupted (try again)
+ * @returns APR_EOF if the queue has been terminated
+ * @returns APR_SUCCESS on a successfull pop
+ */
+APR_DECLARE(apr_status_t) apr_queue_pop_timeout(apr_queue_t *queue, void **data, apr_interval_time_t timeout);
+
+/**
  * push/add an object to the queue, returning immediately if the queue is full
  *
  * @param queue the queue
diff --git a/util-misc/apr_queue.c b/util-misc/apr_queue.c
index 0972493..ef2edfd 100644
--- a/util-misc/apr_queue.c
+++ b/util-misc/apr_queue.c
@@ -322,6 +322,70 @@ APR_DECLARE(apr_status_t) apr_queue_pop(apr_queue_t *queue, void **data)
 
 /**
  * Retrieves the next item from the queue. If there are no
+ * items available, it will block until one becomes available, or
+ * until timeout is elapsed. Once retrieved, the item is placed into
+ * the address specified by'data'.
+ */
+APR_DECLARE(apr_status_t) apr_queue_pop_timeout(apr_queue_t *queue, void **data, apr_interval_time_t timeout)
+{
+    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_timedwait(queue->not_empty, queue->one_big_mutex, timeout);
+            queue->empty_waiters--;
+            /* In the event of a timemout, APR_TIMEUP will be returned */
+            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'.
  */
-- 
2.0.0.rc4