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// Copyright © Tavian Barnes <tavianator@tavianator.com>
// SPDX-License-Identifier: 0BSD
#include "prelude.h"
#include "bar.h"
#include "alloc.h"
#include "atomic.h"
#include "bfstd.h"
#include "bit.h"
#include "dstring.h"
#include "sighook.h"
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <stdarg.h>
#include <stdio.h>
#include <string.h>
#include <sys/ioctl.h>
struct bfs_bar {
int fd;
atomic unsigned int width;
atomic unsigned int height;
struct sighook *exit_hook;
struct sighook *winch_hook;
};
/** Get the terminal size, if possible. */
static int bfs_bar_getsize(struct bfs_bar *bar) {
#ifdef TIOCGWINSZ
struct winsize ws;
if (ioctl(bar->fd, TIOCGWINSZ, &ws) != 0) {
return -1;
}
store(&bar->width, ws.ws_col, relaxed);
store(&bar->height, ws.ws_row, relaxed);
return 0;
#else
errno = ENOTSUP;
return -1;
#endif
}
/** Write a string to the status bar (async-signal-safe). */
static int bfs_bar_write(struct bfs_bar *bar, const char *str, size_t len) {
return xwrite(bar->fd, str, len) == len ? 0 : -1;
}
/** Write a string to the status bar (async-signal-safe). */
static int bfs_bar_puts(struct bfs_bar *bar, const char *str) {
return bfs_bar_write(bar, str, strlen(str));
}
/** Number of decimal digits needed for terminal sizes. */
#define ITOA_DIGITS ((USHRT_WIDTH + 2) / 3)
/** Async Signal Safe itoa(). */
static char *ass_itoa(char *str, unsigned int n) {
char *end = str + ITOA_DIGITS;
*end = '\0';
char *c = end;
do {
*--c = '0' + (n % 10);
n /= 10;
} while (n);
size_t len = end - c;
memmove(str, c, len + 1);
return str + len;
}
/** Update the size of the scrollable region. */
static int bfs_bar_resize(struct bfs_bar *bar) {
static const char PREFIX[] =
"\033D" // IND: Line feed, possibly scrolling
"\033[1A" // CUU: Move cursor up 1 row
"\0337" // DECSC: Save cursor
"\033[;"; // DECSTBM: Set scrollable region
static const char SUFFIX[] =
"r" // (end of DECSTBM)
"\0338" // DECRC: Restore the cursor
"\033[J"; // ED: Erase display from cursor to end
char esc_seq[sizeof(PREFIX) + ITOA_DIGITS + sizeof(SUFFIX)];
// DECSTBM takes the height as the second argument
unsigned int height = load(&bar->height, relaxed) - 1;
char *cur = stpcpy(esc_seq, PREFIX);
cur = ass_itoa(cur, height);
cur = stpcpy(cur, SUFFIX);
return bfs_bar_write(bar, esc_seq, cur - esc_seq);
}
#ifdef SIGWINCH
/** SIGWINCH handler. */
static void bfs_bar_sigwinch(int sig, siginfo_t *info, void *arg) {
struct bfs_bar *bar = arg;
bfs_bar_getsize(bar);
bfs_bar_resize(bar);
}
#endif
/** Reset the scrollable region and hide the bar. */
static int bfs_bar_reset(struct bfs_bar *bar) {
return bfs_bar_puts(bar,
"\0337" // DECSC: Save cursor
"\033[r" // DECSTBM: Reset scrollable region
"\0338" // DECRC: Restore cursor
"\033[J" // ED: Erase display from cursor to end
);
}
/** Signal handler for process-terminating signals. */
static void bfs_bar_sigexit(int sig, siginfo_t *info, void *arg) {
struct bfs_bar *bar = arg;
bfs_bar_reset(bar);
}
/** printf() to the status bar with a single write(). */
attr(printf(2, 3))
static int bfs_bar_printf(struct bfs_bar *bar, const char *format, ...) {
va_list args;
va_start(args, format);
dchar *str = dstrvprintf(format, args);
va_end(args);
if (!str) {
return -1;
}
int ret = bfs_bar_write(bar, str, dstrlen(str));
dstrfree(str);
return ret;
}
struct bfs_bar *bfs_bar_show(void) {
struct bfs_bar *bar = ALLOC(struct bfs_bar);
if (!bar) {
return NULL;
}
char term[L_ctermid];
ctermid(term);
if (strlen(term) == 0) {
errno = ENOTTY;
goto fail;
}
bar->fd = open(term, O_RDWR | O_CLOEXEC);
if (bar->fd < 0) {
goto fail;
}
if (bfs_bar_getsize(bar) != 0) {
goto fail_close;
}
bar->exit_hook = atsigexit(bfs_bar_sigexit, bar);
if (!bar->exit_hook) {
goto fail_close;
}
#ifdef SIGWINCH
bar->winch_hook = sighook(SIGWINCH, bfs_bar_sigwinch, bar, 0);
if (!bar->winch_hook) {
goto fail_hook;
}
#endif
bfs_bar_resize(bar);
return bar;
fail_hook:
sigunhook(bar->exit_hook);
fail_close:
close_quietly(bar->fd);
fail:
free(bar);
return NULL;
}
unsigned int bfs_bar_width(const struct bfs_bar *bar) {
return load(&bar->width, relaxed);
}
int bfs_bar_update(struct bfs_bar *bar, const char *str) {
unsigned int height = load(&bar->height, relaxed);
return bfs_bar_printf(bar,
"\0337" // DECSC: Save cursor
"\033[%u;0f" // HVP: Move cursor to row, column
"\033[K" // EL: Erase line
"\033[7m" // SGR reverse video
"%s"
"\033[27m" // SGR reverse video off
"\0338", // DECRC: Restore cursor
height,
str
);
}
void bfs_bar_hide(struct bfs_bar *bar) {
if (!bar) {
return;
}
sigunhook(bar->winch_hook);
sigunhook(bar->exit_hook);
bfs_bar_reset(bar);
xclose(bar->fd);
free(bar);
}
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