xref: /openbsd-src/usr.bin/tmux/cmd-wait-for.c (revision 8d127fbb7c77fb3db85a57e74220fa31180d44ee)
1 /* $OpenBSD: cmd-wait-for.c,v 1.1 2013/03/25 10:09:05 nicm Exp $ */
2 
3 /*
4  * Copyright (c) 2013 Nicholas Marriott <nicm@users.sourceforge.net>
5  * Copyright (c) 2013 Thiago de Arruda <tpadilha84@gmail.com>
6  *
7  * Permission to use, copy, modify, and distribute this software for any
8  * purpose with or without fee is hereby granted, provided that the above
9  * copyright notice and this permission notice appear in all copies.
10  *
11  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
12  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
13  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
14  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
15  * WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER
16  * IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
17  * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
18  */
19 
20 #include <sys/types.h>
21 
22 #include <stdlib.h>
23 #include <string.h>
24 
25 #include "tmux.h"
26 
27 /*
28  * Block or wake a client on a named wait channel.
29  */
30 
31 enum cmd_retval cmd_wait_for_exec(struct cmd *, struct cmd_q *);
32 
33 const struct cmd_entry cmd_wait_for_entry = {
34 	"wait-for", "wait",
35 	"S", 1, 1,
36 	"[-S] channel",
37 	0,
38 	NULL,
39 	NULL,
40 	cmd_wait_for_exec
41 };
42 
43 struct wait_channel {
44 	const char	       *name;
45 	TAILQ_HEAD(, cmd_q)	waiters;
46 
47 	RB_ENTRY(wait_channel)	entry;
48 };
49 RB_HEAD(wait_channels, wait_channel);
50 struct wait_channels wait_channels = RB_INITIALIZER(wait_channels);
51 
52 int	wait_channel_cmp(struct wait_channel *, struct wait_channel *);
53 RB_PROTOTYPE(wait_channels, wait_channel, entry, wait_channel_cmp);
54 RB_GENERATE(wait_channels, wait_channel, entry, wait_channel_cmp);
55 
56 int
57 wait_channel_cmp(struct wait_channel *wc1, struct wait_channel *wc2)
58 {
59 	return (strcmp(wc1->name, wc2->name));
60 }
61 
62 enum cmd_retval	cmd_wait_for_signal(struct cmd_q *, const char *,
63 		    struct wait_channel *);
64 enum cmd_retval	cmd_wait_for_wait(struct cmd_q *, const char *,
65 		    struct wait_channel *);
66 
67 enum cmd_retval
68 cmd_wait_for_exec(struct cmd *self, struct cmd_q *cmdq)
69 {
70 	struct args     	*args = self->args;
71 	const char		*name = args->argv[0];
72 	struct wait_channel	*wc, wc0;
73 
74 	wc0.name = name;
75 	wc = RB_FIND(wait_channels, &wait_channels, &wc0);
76 
77 	if (args_has(args, 'S'))
78 		return (cmd_wait_for_signal(cmdq, name, wc));
79 	return (cmd_wait_for_wait(cmdq, name, wc));
80 }
81 
82 enum cmd_retval
83 cmd_wait_for_signal(struct cmd_q *cmdq, const char *name,
84     struct wait_channel *wc)
85 {
86 	struct cmd_q	*wq, *wq1;
87 
88 	if (wc == NULL || TAILQ_EMPTY(&wc->waiters)) {
89 		cmdq_error(cmdq, "no waiting clients on %s", name);
90 		return (CMD_RETURN_ERROR);
91 	}
92 
93 	TAILQ_FOREACH_SAFE(wq, &wc->waiters, waitentry, wq1) {
94 		TAILQ_REMOVE(&wc->waiters, wq, waitentry);
95 		if (!cmdq_free(wq))
96 			cmdq_continue(wq);
97 	}
98 	RB_REMOVE(wait_channels, &wait_channels, wc);
99 	free((void*) wc->name);
100 	free(wc);
101 
102 	return (CMD_RETURN_NORMAL);
103 }
104 
105 enum cmd_retval
106 cmd_wait_for_wait(struct cmd_q *cmdq, const char *name,
107     struct wait_channel *wc)
108 {
109 	if (cmdq->client == NULL || cmdq->client->session != NULL) {
110 		cmdq_error(cmdq, "not able to wait");
111 		return (CMD_RETURN_ERROR);
112 	}
113 
114 	if (wc == NULL) {
115 		wc = xmalloc(sizeof *wc);
116 		wc->name = xstrdup(name);
117 		TAILQ_INIT(&wc->waiters);
118 		RB_INSERT(wait_channels, &wait_channels, wc);
119 	}
120 	TAILQ_INSERT_TAIL(&wc->waiters, cmdq, waitentry);
121 	cmdq->references++;
122 
123 	return (CMD_RETURN_WAIT);
124 }
125