nsxiv/autoreload.c
NRK 94d531fd82 autoreload: simplify and cleanup (#342)
the current code is quite hacky and complex as it mixes multiple pointers. all
of this complexity is unnecessary. drop it by introducing an explicit scratch
buffer instead of implicitly abusing `arl->filename` as one. this also reduces
some unnecessary allocation overhead.

additionally, the argument to arl_setup must be the result of `realpath(3)` (as
commented in `nsxiv.h`). instead of commenting it, assert it.

and lastly, rename `arl_setup` to `arl_add` since it's not doing any "setup"
but rather *adding* a file to watch.

Reviewed-on: https://codeberg.org/nsxiv/nsxiv/pulls/342
Reviewed-by: explosion-mental <explosion-mental@noreply.codeberg.org>
2022-07-30 10:05:10 +02:00

147 lines
3.3 KiB
C

/* Copyright 2017 Max Voit, Bert Muennich
* Copyright 2022 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)
{
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;
const struct inotify_event *e;
/* inotify_event aligned buffer */
static union { char d[4096]; struct inotify_event e; } buf;
while (true) {
ssize_t len = read(arl->fd, buf.d, sizeof(buf.d));
if (len == -1) {
if (errno == EINTR)
continue;
break;
}
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;
} else if (e->wd == arl->wd_file && (e->mask & IN_DELETE_SELF)) {
rm_watch(arl->fd, &arl->wd_file);
} 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 */