1 files changed, 264 insertions, 0 deletions
diff --git a/cmd-wait-for.c b/cmd-wait-for.c
new file mode 100644
index 0000000..8a6aa25
--- /dev/null
+++ b/cmd-wait-for.c
@@ -0,0 +1,264 @@
+/* $OpenBSD$ */
+
+/*
+ * Copyright (c) 2013 Nicholas Marriott <nicholas.marriott@gmail.com>
+ * Copyright (c) 2013 Thiago de Arruda <tpadilha84@gmail.com>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER
+ * IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
+ * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <sys/types.h>
+
+#include <stdlib.h>
+#include <string.h>
+
+#include "tmux.h"
+
+/*
+ * Block or wake a client on a named wait channel.
+ */
+
+static enum cmd_retval cmd_wait_for_exec(struct cmd *, struct cmdq_item *);
+
+const struct cmd_entry cmd_wait_for_entry = {
+	.name = "wait-for",
+	.alias = "wait",
+
+	.args = { "LSU", 1, 1, NULL },
+	.usage = "[-L|-S|-U] channel",
+
+	.flags = 0,
+	.exec = cmd_wait_for_exec
+};
+
+struct wait_item {
+	struct cmdq_item	*item;
+	TAILQ_ENTRY(wait_item)	 entry;
+};
+
+struct wait_channel {
+	const char	       *name;
+	int			locked;
+	int			woken;
+
+	TAILQ_HEAD(, wait_item)	waiters;
+	TAILQ_HEAD(, wait_item)	lockers;
+
+	RB_ENTRY(wait_channel)	entry;
+};
+RB_HEAD(wait_channels, wait_channel);
+static struct wait_channels wait_channels = RB_INITIALIZER(wait_channels);
+
+static int wait_channel_cmp(struct wait_channel *, struct wait_channel *);
+RB_GENERATE_STATIC(wait_channels, wait_channel, entry, wait_channel_cmp);
+
+static int
+wait_channel_cmp(struct wait_channel *wc1, struct wait_channel *wc2)
+{
+	return (strcmp(wc1->name, wc2->name));
+}
+
+static enum cmd_retval	cmd_wait_for_signal(struct cmdq_item *, const char *,
+			    struct wait_channel *);
+static enum cmd_retval	cmd_wait_for_wait(struct cmdq_item *, const char *,
+			    struct wait_channel *);
+static enum cmd_retval	cmd_wait_for_lock(struct cmdq_item *, const char *,
+			    struct wait_channel *);
+static enum cmd_retval	cmd_wait_for_unlock(struct cmdq_item *, const char *,
+			    struct wait_channel *);
+
+static struct wait_channel	*cmd_wait_for_add(const char *);
+static void			 cmd_wait_for_remove(struct wait_channel *);
+
+static struct wait_channel *
+cmd_wait_for_add(const char *name)
+{
+	struct wait_channel *wc;
+
+	wc = xmalloc(sizeof *wc);
+	wc->name = xstrdup(name);
+
+	wc->locked = 0;
+	wc->woken = 0;
+
+	TAILQ_INIT(&wc->waiters);
+	TAILQ_INIT(&wc->lockers);
+
+	RB_INSERT(wait_channels, &wait_channels, wc);
+
+	log_debug("add wait channel %s", wc->name);
+
+	return (wc);
+}
+
+static void
+cmd_wait_for_remove(struct wait_channel *wc)
+{
+	if (wc->locked)
+		return;
+	if (!TAILQ_EMPTY(&wc->waiters) || !wc->woken)
+		return;
+
+	log_debug("remove wait channel %s", wc->name);
+
+	RB_REMOVE(wait_channels, &wait_channels, wc);
+
+	free((void *)wc->name);
+	free(wc);
+}
+
+static enum cmd_retval
+cmd_wait_for_exec(struct cmd *self, struct cmdq_item *item)
+{
+	struct args     	*args = cmd_get_args(self);
+	const char		*name = args_string(args, 0);
+	struct wait_channel	*wc, find;
+
+	find.name = name;
+	wc = RB_FIND(wait_channels, &wait_channels, &find);
+
+	if (args_has(args, 'S'))
+		return (cmd_wait_for_signal(item, name, wc));
+	if (args_has(args, 'L'))
+		return (cmd_wait_for_lock(item, name, wc));
+	if (args_has(args, 'U'))
+		return (cmd_wait_for_unlock(item, name, wc));
+	return (cmd_wait_for_wait(item, name, wc));
+}
+
+static enum cmd_retval
+cmd_wait_for_signal(__unused struct cmdq_item *item, const char *name,
+    struct wait_channel *wc)
+{
+	struct wait_item	*wi, *wi1;
+
+	if (wc == NULL)
+		wc = cmd_wait_for_add(name);
+
+	if (TAILQ_EMPTY(&wc->waiters) && !wc->woken) {
+		log_debug("signal wait channel %s, no waiters", wc->name);
+		wc->woken = 1;
+		return (CMD_RETURN_NORMAL);
+	}
+	log_debug("signal wait channel %s, with waiters", wc->name);
+
+	TAILQ_FOREACH_SAFE(wi, &wc->waiters, entry, wi1) {
+		cmdq_continue(wi->item);
+
+		TAILQ_REMOVE(&wc->waiters, wi, entry);
+		free(wi);
+	}
+
+	cmd_wait_for_remove(wc);
+	return (CMD_RETURN_NORMAL);
+}
+
+static enum cmd_retval
+cmd_wait_for_wait(struct cmdq_item *item, const char *name,
+    struct wait_channel *wc)
+{
+	struct client		*c = cmdq_get_client(item);
+	struct wait_item	*wi;
+
+	if (c == NULL) {
+		cmdq_error(item, "not able to wait");
+		return (CMD_RETURN_ERROR);
+	}
+
+	if (wc == NULL)
+		wc = cmd_wait_for_add(name);
+
+	if (wc->woken) {
+		log_debug("wait channel %s already woken (%p)", wc->name, c);
+		cmd_wait_for_remove(wc);
+		return (CMD_RETURN_NORMAL);
+	}
+	log_debug("wait channel %s not woken (%p)", wc->name, c);
+
+	wi = xcalloc(1, sizeof *wi);
+	wi->item = item;
+	TAILQ_INSERT_TAIL(&wc->waiters, wi, entry);
+
+	return (CMD_RETURN_WAIT);
+}
+
+static enum cmd_retval
+cmd_wait_for_lock(struct cmdq_item *item, const char *name,
+    struct wait_channel *wc)
+{
+	struct wait_item	*wi;
+
+	if (cmdq_get_client(item) == NULL) {
+		cmdq_error(item, "not able to lock");
+		return (CMD_RETURN_ERROR);
+	}
+
+	if (wc == NULL)
+		wc = cmd_wait_for_add(name);
+
+	if (wc->locked) {
+		wi = xcalloc(1, sizeof *wi);
+		wi->item = item;
+		TAILQ_INSERT_TAIL(&wc->lockers, wi, entry);
+		return (CMD_RETURN_WAIT);
+	}
+	wc->locked = 1;
+
+	return (CMD_RETURN_NORMAL);
+}
+
+static enum cmd_retval
+cmd_wait_for_unlock(struct cmdq_item *item, const char *name,
+    struct wait_channel *wc)
+{
+	struct wait_item	*wi;
+
+	if (wc == NULL || !wc->locked) {
+		cmdq_error(item, "channel %s not locked", name);
+		return (CMD_RETURN_ERROR);
+	}
+
+	if ((wi = TAILQ_FIRST(&wc->lockers)) != NULL) {
+		cmdq_continue(wi->item);
+		TAILQ_REMOVE(&wc->lockers, wi, entry);
+		free(wi);
+	} else {
+		wc->locked = 0;
+		cmd_wait_for_remove(wc);
+	}
+
+	return (CMD_RETURN_NORMAL);
+}
+
+void
+cmd_wait_for_flush(void)
+{
+	struct wait_channel	*wc, *wc1;
+	struct wait_item	*wi, *wi1;
+
+	RB_FOREACH_SAFE(wc, wait_channels, &wait_channels, wc1) {
+		TAILQ_FOREACH_SAFE(wi, &wc->waiters, entry, wi1) {
+			cmdq_continue(wi->item);
+			TAILQ_REMOVE(&wc->waiters, wi, entry);
+			free(wi);
+		}
+		wc->woken = 1;
+		TAILQ_FOREACH_SAFE(wi, &wc->lockers, entry, wi1) {
+			cmdq_continue(wi->item);
+			TAILQ_REMOVE(&wc->lockers, wi, entry);
+			free(wi);
+		}
+		wc->locked = 0;
+		cmd_wait_for_remove(wc);
+	}
+}