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/*
* Copyright 2016 Garrett D'Amore <garrett@damore.org>
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom
* the Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included
* in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*/
#include "nng_impl.h"
/*
* Message queue. These operate in some respects like Go channels,
* but as we have access to the internals, we have made some fundamental
* differences and improvements. For example, these can grow, and either
* side can close, and they may be closed more than once.
*/
struct nni_msgqueue {
nni_mutex_t mq_lock;
nni_cond_t mq_readable;
nni_cond_t mq_writeable;
int mq_cap;
int mq_len;
int mq_get;
int mq_put;
int mq_closed;
nng_msg_t *mq_msgs;
};
int
nni_msgqueue_create(nni_msgqueue_t *mqp, int cap)
{
struct nni_msgqueue *mq;
int rv;
if (cap < 1) {
return (NNG_EINVAL);
}
if ((mq = nni_alloc(sizeof (*mq))) == NULL) {
return (NNG_ENOMEM);
}
if ((rv = nni_mutex_create(&mq->mq_lock)) != 0) {
nni_free(mq, sizeof (*mq));
return (rv);
}
if ((rv = nni_cond_create(&mq->mq_readable, mq->mq_lock)) != 0) {
nni_mutex_destroy(mq->mq_lock);
nni_free(mq, sizeof (*mq));
return (NNG_ENOMEM);
}
if ((rv = nni_cond_create(&mq->mq_writeable, mq->mq_lock)) != 0) {
nni_cond_destroy(mq->mq_readable);
nni_mutex_destroy(mq->mq_lock);
return (NNG_ENOMEM);
}
if ((mq->mq_msgs = nni_alloc(sizeof (nng_msg_t) * cap)) == NULL) {
nni_cond_destroy(mq->mq_writeable);
nni_cond_destroy(mq->mq_readable);
nni_mutex_destroy(mq->mq_lock);
return (NNG_ENOMEM);
}
mq->mq_cap = cap;
mq->mq_len = 0;
mq->mq_get = 0;
mq->mq_put = 0;
mq->mq_closed = 0;
*mqp = mq;
return (0);
}
void
nni_msgqueue_destroy(nni_msgqueue_t mq)
{
nni_msg_t msg;
nni_cond_destroy(mq->mq_writeable);
nni_cond_destroy(mq->mq_readable);
nni_mutex_destroy(mq->mq_lock);
/* Free any orphaned messages. */
while (mq->mq_len > 0) {
msg = mq->mq_msgs[mq->mq_get];
mq->mq_get++;
if (mq->mq_get > mq->mq_cap) {
mq->mq_get = 0;
}
mq->mq_len--;
nni_msg_free(msg);
}
nni_free(mq->mq_msgs, mq->mq_cap * sizeof (nng_msg_t));
nni_free(mq, sizeof (*mq));
}
/*
* nni_msgqueue_signal raises a signal on the signal object. This allows a
* waiter to be signaled, so that it can be woken e.g. due to a pipe closing.
* Note that the signal object must be *zero* if no signal is raised.
*/
void
nni_msgqueue_signal(nni_msgqueue_t mq, int *signal)
{
nni_mutex_enter(mq->mq_lock);
*signal = 1;
/*
* We have to wake everyone.
*/
nni_cond_broadcast(mq->mq_readable);
nni_cond_broadcast(mq->mq_writeable);
nni_mutex_exit(mq->mq_lock);
}
int
nni_msgqueue_put_sig(nni_msgqueue_t mq, nni_msg_t msg, int tmout, int *signal)
{
uint64_t expire, now;
if (tmout > 0) {
expire = nni_clock() + tmout;
}
nni_mutex_enter(mq->mq_lock);
while ((!mq->mq_closed) && (mq->mq_len == mq->mq_cap) && (!*signal)) {
if (tmout == 0) {
nni_mutex_exit(mq->mq_lock);
return (NNG_EAGAIN);
}
if (tmout < 0) {
(void) nni_cond_wait(mq->mq_writeable);
continue;
}
now = nni_clock();
if (now >= expire) {
nni_mutex_exit(mq->mq_lock);
return (NNG_ETIMEDOUT);
}
(void) nni_cond_timedwait(mq->mq_writeable, (expire - now));
}
if (mq->mq_closed) {
nni_mutex_exit(mq->mq_lock);
return (NNG_ECLOSED);
}
if ((mq->mq_len == mq->mq_cap) && (*signal)) {
/*
* We are being interrupted. We only allow an interrupt
* if there is no room though, because we'd really prefer
* to queue the data. Otherwise our failure to queue
* the data could lead to starvation.
*/
nni_mutex_exit(mq->mq_lock);
return (NNG_EINTR);
}
mq->mq_msgs[mq->mq_put] = msg;
mq->mq_put++;
if (mq->mq_put == mq->mq_cap) {
mq->mq_put = 0;
}
mq->mq_len++;
if (mq->mq_len == 1) {
(void) nni_cond_signal(mq->mq_readable);
}
nni_mutex_exit(mq->mq_lock);
return (0);
}
int
nni_msgqueue_get_sig(nni_msgqueue_t mq, nni_msg_t *msgp, int tmout, int *signal)
{
uint64_t expire, now;
if (tmout > 0) {
expire = nni_clock() + tmout;
}
nni_mutex_enter(mq->mq_lock);
while ((!mq->mq_closed) && (mq->mq_len == 0) && (*signal == 0)) {
if (tmout == 0) {
nni_mutex_exit(mq->mq_lock);
return (NNG_EAGAIN);
}
if (tmout < 0) {
(void) nni_cond_wait(mq->mq_readable);
continue;
}
now = nni_clock();
if (now >= expire) {
nni_mutex_exit(mq->mq_lock);
return (NNG_ETIMEDOUT);
}
(void) nni_cond_timedwait(mq->mq_readable, (expire - now));
}
if (mq->mq_closed) {
nni_mutex_exit(mq->mq_lock);
return (NNG_ECLOSED);
}
if ((mq->mq_len == 0) && (*signal)) {
/*
* We are being interrupted. We only allow an interrupt
* if there is no data though, because we'd really prefer
* to give back the data. Otherwise our failure to deal
* with the data could lead to starvation.
*/
nni_mutex_exit(mq->mq_lock);
return (NNG_EINTR);
}
*msgp = mq->mq_msgs[mq->mq_get];
mq->mq_len--;
mq->mq_get++;
if (mq->mq_get == mq->mq_cap) {
mq->mq_get = 0;
}
mq->mq_len++;
if (mq->mq_len == (mq->mq_cap - 1)) {
(void) nni_cond_signal(mq->mq_writeable);
}
nni_mutex_exit(mq->mq_lock);
return (0);
}
int
nni_msgqueue_get(nni_msgqueue_t mq, nni_msg_t *msgp, int tmout)
{
int nosig = 0;
return (nni_msgqueue_get_sig(mq, msgp, tmout, &nosig));
}
int
nni_msgqueue_put(nni_msgqueue_t mq, nni_msg_t msg, int tmout)
{
int nosig = 0;
return (nni_msgqueue_put_sig(mq, msg, tmout, &nosig));
}
void
nni_msgqueue_close(nni_msgqueue_t mq)
{
nni_msg_t msg;
nni_mutex_enter(mq->mq_lock);
mq->mq_closed = 1;
nni_cond_broadcast(mq->mq_writeable);
nni_cond_broadcast(mq->mq_readable);
/* Free the messages orphaned in the queue. */
while (mq->mq_len > 0) {
msg = mq->mq_msgs[mq->mq_get];
mq->mq_get++;
if (mq->mq_get > mq->mq_cap) {
mq->mq_get = 0;
}
mq->mq_len--;
nni_msg_free(msg);
}
nni_mutex_exit(mq->mq_lock);
}
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