1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
|
/*
* Copyright 2016 Garrett D'Amore <garrett@damore.org>
*
* This software is supplied under the terms of the MIT License, a
* copy of which should be located in the distribution where this
* file was obtained (LICENSE.txt). A copy of the license may also be
* found online at https://opensource.org/licenses/MIT.
*/
#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);
}
|
