1 /*
2 Copyright (c) 2012-2013 Martin Sustrik All rights reserved.
3
4 Permission is hereby granted, free of charge, to any person obtaining a copy
5 of this software and associated documentation files (the "Software"),
6 to deal in the Software without restriction, including without limitation
7 the rights to use, copy, modify, merge, publish, distribute, sublicense,
8 and/or sell copies of the Software, and to permit persons to whom
9 the Software is furnished to do so, subject to the following conditions:
10
11 The above copyright notice and this permission notice shall be included
12 in all copies or substantial portions of the Software.
13
14 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
17 THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
18 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
19 FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
20 IN THE SOFTWARE.
21 */
22
23 #include "msgqueue.h"
24
25 #include "../../utils/alloc.h"
26 #include "../../utils/fast.h"
27 #include "../../utils/err.h"
28
29 #include <string.h>
30
nn_msgqueue_init(struct nn_msgqueue * self,size_t maxmem)31 void nn_msgqueue_init (struct nn_msgqueue *self, size_t maxmem)
32 {
33 struct nn_msgqueue_chunk *chunk;
34
35 self->count = 0;
36 self->mem = 0;
37 self->maxmem = maxmem;
38
39 chunk = nn_alloc (sizeof (struct nn_msgqueue_chunk), "msgqueue chunk");
40 alloc_assert (chunk);
41 chunk->next = NULL;
42
43 self->out.chunk = chunk;
44 self->out.pos = 0;
45 self->in.chunk = chunk;
46 self->in.pos = 0;
47
48 self->cache = NULL;
49 }
50
nn_msgqueue_term(struct nn_msgqueue * self)51 void nn_msgqueue_term (struct nn_msgqueue *self)
52 {
53 int rc;
54 struct nn_msg msg;
55
56 /* Deallocate messages in the pipe. */
57 while (1) {
58 rc = nn_msgqueue_recv (self, &msg);
59 if (rc == -EAGAIN)
60 break;
61 errnum_assert (rc >= 0, -rc);
62 nn_msg_term (&msg);
63 }
64
65 /* There are no more messages in the pipe so there's at most one chunk
66 in the queue. Deallocate it. */
67 nn_assert (self->in.chunk == self->out.chunk);
68 nn_free (self->in.chunk);
69
70 /* Deallocate the cached chunk, if any. */
71 if (self->cache)
72 nn_free (self->cache);
73 }
74
nn_msgqueue_empty(struct nn_msgqueue * self)75 int nn_msgqueue_empty (struct nn_msgqueue *self)
76 {
77 return self->count == 0 ? 1 : 0;
78 }
79
nn_msgqueue_send(struct nn_msgqueue * self,struct nn_msg * msg)80 int nn_msgqueue_send (struct nn_msgqueue *self, struct nn_msg *msg)
81 {
82 size_t msgsz;
83
84 /* By allowing one message of arbitrary size to be written to the queue,
85 we allow even messages that exceed max buffer size to pass through.
86 Beyond that we'll apply the buffer limit as specified by the user. */
87 msgsz = nn_chunkref_size (&msg->sphdr) + nn_chunkref_size (&msg->body);
88 if (nn_slow (self->count > 0 && self->mem + msgsz >= self->maxmem))
89 return -EAGAIN;
90
91 /* Adjust the statistics. */
92 ++self->count;
93 self->mem += msgsz;
94
95 /* Move the content of the message to the pipe. */
96 nn_msg_mv (&self->out.chunk->msgs [self->out.pos], msg);
97 ++self->out.pos;
98
99 /* If there's no space for a new message in the pipe, either re-use
100 the cache chunk or allocate a new chunk if it does not exist. */
101 if (nn_slow (self->out.pos == NN_MSGQUEUE_GRANULARITY)) {
102 if (nn_slow (!self->cache)) {
103 self->cache = nn_alloc (sizeof (struct nn_msgqueue_chunk),
104 "msgqueue chunk");
105 alloc_assert (self->cache);
106 self->cache->next = NULL;
107 }
108 self->out.chunk->next = self->cache;
109 self->out.chunk = self->cache;
110 self->cache = NULL;
111 self->out.pos = 0;
112 }
113
114 return 0;
115 }
116
nn_msgqueue_recv(struct nn_msgqueue * self,struct nn_msg * msg)117 int nn_msgqueue_recv (struct nn_msgqueue *self, struct nn_msg *msg)
118 {
119 struct nn_msgqueue_chunk *o;
120
121 /* If there is no message in the queue. */
122 if (nn_slow (!self->count))
123 return -EAGAIN;
124
125 /* Move the message from the pipe to the user. */
126 nn_msg_mv (msg, &self->in.chunk->msgs [self->in.pos]);
127
128 /* Move to the next position. */
129 ++self->in.pos;
130 if (nn_slow (self->in.pos == NN_MSGQUEUE_GRANULARITY)) {
131 o = self->in.chunk;
132 self->in.chunk = self->in.chunk->next;
133 self->in.pos = 0;
134 if (nn_fast (!self->cache))
135 self->cache = o;
136 else
137 nn_free (o);
138 }
139
140 /* Adjust the statistics. */
141 --self->count;
142 self->mem -= (nn_chunkref_size (&msg->sphdr) +
143 nn_chunkref_size (&msg->body));
144
145 return 0;
146 }
147
148