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// Copyright © Tavian Barnes <tavianator@tavianator.com>
// SPDX-License-Identifier: 0BSD
#include "prelude.h"
#include "bar.h"
#include "atomic.h"
#include "bfstd.h"
#include "bit.h"
#include "dstring.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;
};
/** The global status bar instance. */
static struct bfs_bar the_bar = {
.fd = -1,
};
/** 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
}
/** Async Signal Safe puts(). */
static int ass_puts(int fd, const char *str) {
size_t len = strlen(str);
return xwrite(fd, str, len) == len ? 0 : -1;
}
/** 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) {
char esc_seq[12 + ITOA_DIGITS] =
"\0337" // DECSC: Save cursor
"\033[;"; // DECSTBM: Set scrollable region
// DECSTBM takes the height as the second argument
unsigned int height = load(&bar->height, relaxed);
char *ptr = esc_seq + strlen(esc_seq);
ptr = ass_itoa(ptr, height - 1);
strcpy(ptr,
"r" // DECSTBM
"\0338" // DECRC: Restore the cursor
"\033[J" // ED: Erase display from cursor to end
);
return ass_puts(bar->fd, esc_seq);
}
#ifdef SIGWINCH
/** SIGWINCH handler. */
static void sighand_winch(int sig) {
int error = errno;
bfs_bar_getsize(&the_bar);
bfs_bar_resize(&the_bar);
errno = error;
}
#endif
/** Reset the scrollable region and hide the bar. */
static int bfs_bar_reset(struct bfs_bar *bar) {
return ass_puts(bar->fd,
"\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 sighand_reset(int sig) {
bfs_bar_reset(&the_bar);
raise(sig);
}
/** Register sighand_reset() for a signal. */
static void reset_before_death_by(int sig) {
struct sigaction sa = {
.sa_handler = sighand_reset,
.sa_flags = SA_RESETHAND,
};
sigemptyset(&sa.sa_mask);
sigaction(sig, &sa, NULL);
}
/** 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 = ass_puts(bar->fd, str);
dstrfree(str);
return ret;
}
struct bfs_bar *bfs_bar_show(void) {
if (the_bar.fd >= 0) {
errno = EBUSY;
goto fail;
}
char term[L_ctermid];
ctermid(term);
if (strlen(term) == 0) {
errno = ENOTTY;
goto fail;
}
the_bar.fd = open(term, O_RDWR | O_CLOEXEC);
if (the_bar.fd < 0) {
goto fail;
}
if (bfs_bar_getsize(&the_bar) != 0) {
goto fail_close;
}
reset_before_death_by(SIGABRT);
reset_before_death_by(SIGINT);
reset_before_death_by(SIGPIPE);
reset_before_death_by(SIGQUIT);
reset_before_death_by(SIGTERM);
#ifdef SIGWINCH
struct sigaction sa = {
.sa_handler = sighand_winch,
.sa_flags = SA_RESTART,
};
sigemptyset(&sa.sa_mask);
sigaction(SIGWINCH, &sa, NULL);
#endif
unsigned int height = load(&the_bar.height, relaxed);
bfs_bar_printf(&the_bar,
"\n" // Make space for the bar
"\0337" // DECSC: Save cursor
"\033[;%ur" // DECSTBM: Set scrollable region
"\0338" // DECRC: Restore cursor
"\033[1A", // CUU: Move cursor up 1 row
height - 1
);
return &the_bar;
fail_close:
close_quietly(the_bar.fd);
the_bar.fd = -1;
fail:
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;
}
signal(SIGABRT, SIG_DFL);
signal(SIGINT, SIG_DFL);
signal(SIGPIPE, SIG_DFL);
signal(SIGQUIT, SIG_DFL);
signal(SIGTERM, SIG_DFL);
#ifdef SIGWINCH
signal(SIGWINCH, SIG_DFL);
#endif
bfs_bar_reset(bar);
xclose(bar->fd);
bar->fd = -1;
}
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