nsxiv/autoreload.c

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/* Copyright 2017 Max Voit, Bert Muennich
2023-01-15 10:26:46 +01:00
* Copyright 2022-2023 nsxiv contributors
*
* This file is a part of nsxiv.
*
* nsxiv is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published
* by the Free Software Foundation; either version 2 of the License,
* or (at your option) any later version.
*
* nsxiv is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with nsxiv. If not, see <http://www.gnu.org/licenses/>.
*/
#include "nsxiv.h"
#if HAVE_INOTIFY
#include <assert.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <sys/inotify.h>
#include <unistd.h>
static struct { char *buf; size_t len; } scratch;
void arl_init(arl_t *arl)
{
arl->fd = inotify_init1(IN_CLOEXEC | IN_NONBLOCK);
arl->wd_dir = arl->wd_file = -1;
if (arl->fd == -1)
error(0, 0, "Could not initialize inotify, no automatic image reloading");
}
CLEANUP void arl_cleanup(arl_t *arl)
{
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if (arl->fd != -1)
close(arl->fd);
free(scratch.buf);
}
static void rm_watch(int fd, int *wd)
{
if (*wd != -1) {
inotify_rm_watch(fd, *wd);
*wd = -1;
}
}
static void add_watch(int fd, int *wd, const char *path, uint32_t mask)
{
*wd = inotify_add_watch(fd, path, mask);
if (*wd == -1)
error(0, errno, "inotify: %s", path);
}
static char *arl_scratch_push(const char *filepath, size_t len)
{
if (scratch.len < len + 1) {
scratch.len = len + 1;
scratch.buf = erealloc(scratch.buf, scratch.len);
}
scratch.buf[len] = '\0';
return memcpy(scratch.buf, filepath, len);
}
void arl_add(arl_t *arl, const char *filepath)
{
char *base, *dir;
if (arl->fd == -1)
return;
rm_watch(arl->fd, &arl->wd_dir);
rm_watch(arl->fd, &arl->wd_file);
add_watch(arl->fd, &arl->wd_file, filepath, IN_CLOSE_WRITE | IN_DELETE_SELF);
base = strrchr(filepath, '/');
assert(base != NULL); /* filepath must be result of `realpath(3)` */
dir = arl_scratch_push(filepath, base - filepath);
add_watch(arl->fd, &arl->wd_dir, dir, IN_CREATE | IN_MOVED_TO);
arl->filename = arl_scratch_push(base + 1, strlen(base + 1));
}
bool arl_handle(arl_t *arl)
{
bool reload = false;
char *ptr;
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const struct inotify_event *e;
/* inotify_event aligned buffer */
static union { char d[4096]; struct inotify_event e; } buf;
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while (true) {
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ssize_t len = read(arl->fd, buf.d, sizeof(buf.d));
if (len == -1) {
if (errno == EINTR)
continue;
break;
}
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for (ptr = buf.d; ptr < buf.d + len; ptr += sizeof(*e) + e->len) {
e = (const struct inotify_event*) ptr;
if (e->wd == arl->wd_file && (e->mask & IN_CLOSE_WRITE)) {
reload = true;
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} else if (e->wd == arl->wd_file && (e->mask & IN_DELETE_SELF)) {
rm_watch(arl->fd, &arl->wd_file);
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} else if (e->wd == arl->wd_dir && (e->mask & (IN_CREATE | IN_MOVED_TO))) {
if (STREQ(e->name, arl->filename))
reload = true;
}
}
}
return reload;
}
#else
void arl_init(arl_t *arl)
{
arl->fd = -1;
}
void arl_cleanup(arl_t *arl)
{
(void) arl;
}
void arl_add(arl_t *arl, const char *filepath)
{
(void) arl;
(void) filepath;
}
bool arl_handle(arl_t *arl)
{
(void) arl;
return false;
}
#endif /* HAVE_INOTIFY */