/* $OpenBSD$ */

/*
* Copyright (c) 2013 Nicholas Marriott <[email protected]>
* Copyright (c) 2013 Thiago de Arruda <[email protected]>
*
* 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(__UNCONST(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);
       }
}

You are viewing proxied material from ftp.icm.edu.pl. The copyright of proxied material belongs to its original authors. Any comments or complaints in relation to proxied material should be directed to the original authors of the content concerned. Please see the disclaimer for more details.