[git commit] lineedit: print prompt and editing operations to stderr
Denys Vlasenko
vda.linux at googlemail.com
Sat Apr 13 16:40:20 UTC 2024
commit: https://git.busybox.net/busybox/commit/?id=fd47f056765aed515f4c71118813f07be1402bee
branch: https://git.busybox.net/busybox/commit/?id=refs/heads/master
For shells, this is mandated by standards
function old new delta
input_backward 215 231 +16
read_line_input 3015 3028 +13
draw_custom 66 78 +12
put_cur_glyph_and_inc_cursor 149 159 +10
put_prompt_custom 47 56 +9
show_history 40 46 +6
input_tab 927 933 +6
input_delete 136 142 +6
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 8/0 up/down: 78/0) Total: 78 bytes
Signed-off-by: Denys Vlasenko <vda.linux at googlemail.com>
---
libbb/lineedit.c | 62 +++++++++++++++++++++++++++++++-------------------------
1 file changed, 34 insertions(+), 28 deletions(-)
diff --git a/libbb/lineedit.c b/libbb/lineedit.c
index bdae10914..543a3f11c 100644
--- a/libbb/lineedit.c
+++ b/libbb/lineedit.c
@@ -345,7 +345,7 @@ static unsigned save_string(char *dst, unsigned maxsize)
return i;
}
}
-/* I thought just fputwc(c, stdout) would work. But no... */
+/* I thought just fputwc(c, stderr) would work. But no... */
static void BB_PUTCHAR(wchar_t c)
{
if (unicode_status == UNICODE_ON) {
@@ -354,11 +354,11 @@ static void BB_PUTCHAR(wchar_t c)
ssize_t len = wcrtomb(buf, c, &mbst);
if (len > 0) {
buf[len] = '\0';
- fputs_stdout(buf);
+ fputs(buf, stderr);
}
} else {
/* In this case, c is always one byte */
- putchar(c);
+ bb_putchar_stderr(c);
}
}
# if ENABLE_UNICODE_COMBINING_WCHARS || ENABLE_UNICODE_WIDE_WCHARS
@@ -404,7 +404,7 @@ static void save_string(char *dst, unsigned maxsize)
safe_strncpy(dst, command_ps, maxsize);
}
# endif
-# define BB_PUTCHAR(c) bb_putchar(c)
+# define BB_PUTCHAR(c) bb_putchar_stderr(c)
/* Should never be called: */
int adjust_width_and_validate_wc(unsigned *width_adj, int wc);
#endif
@@ -463,7 +463,7 @@ static void put_cur_glyph_and_inc_cursor(void)
if (c == BB_NUL)
c = ' ';
BB_PUTCHAR(c);
- bb_putchar('\b');
+ bb_putchar_stderr('\b');
#endif
cmdedit_y++;
if (!ENABLE_UNICODE_WIDE_WCHARS || ofs_to_right == 0) {
@@ -489,12 +489,12 @@ static void goto_new_line(void)
put_till_end_and_adv_cursor();
/* "cursor == 0" is only if prompt is "" and user input is empty */
if (cursor == 0 || cmdedit_x != 0)
- bb_putchar('\n');
+ bb_putchar_stderr('\n');
}
static void beep(void)
{
- bb_putchar('\007');
+ bb_putchar_stderr('\007');
}
/* Full or last/sole prompt line, reset edit cursor, calculate terminal cursor.
@@ -502,7 +502,10 @@ static void beep(void)
*/
static void put_prompt_custom(bool is_full)
{
- fputs_stdout((is_full ? cmdedit_prompt : prompt_last_line));
+ /* https://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html
+ * says that shells must write $PSn to stderr, not stdout.
+ */
+ fputs((is_full ? cmdedit_prompt : prompt_last_line), stderr);
cursor = 0;
cmdedit_y = cmdedit_prmt_len / cmdedit_termw; /* new quasireal y */
cmdedit_x = cmdedit_prmt_len % cmdedit_termw;
@@ -539,15 +542,15 @@ static void input_backward(unsigned num)
/* This is longer by 5 bytes on x86.
* Also gets miscompiled for ARM users
* (busybox.net/bugs/view.php?id=2274).
- * printf(("\b\b\b\b" + 4) - num);
+ * fprintf(("\b\b\b\b" + 4) - num, stderr);
* return;
*/
do {
- bb_putchar('\b');
+ bb_putchar_stderr('\b');
} while (--num);
return;
}
- printf(ESC"[%uD", num);
+ fprintf(stderr, ESC"[%uD", num);
return;
}
@@ -572,7 +575,7 @@ static void input_backward(unsigned num)
*/
unsigned sv_cursor;
/* go to 1st column; go up to first line */
- printf("\r" ESC"[%uA", cmdedit_y);
+ fprintf(stderr, "\r" ESC"[%uA", cmdedit_y);
cmdedit_y = 0;
sv_cursor = cursor;
put_prompt_last_line(); /* sets cursor to 0 */
@@ -587,12 +590,12 @@ static void input_backward(unsigned num)
cmdedit_x = (cmdedit_termw * cmdedit_y - num) % cmdedit_termw;
cmdedit_y -= lines_up;
/* go to 1st column; go up */
- printf("\r" ESC"[%uA", lines_up);
+ fprintf(stderr, "\r" ESC"[%uA", lines_up);
/* go to correct column.
* xterm, konsole, Linux VT interpret 0 as 1 below! wow.
* need to *make sure* we skip it if cmdedit_x == 0 */
if (cmdedit_x)
- printf(ESC"[%uC", cmdedit_x);
+ fprintf(stderr, ESC"[%uC", cmdedit_x);
}
}
@@ -600,11 +603,11 @@ static void input_backward(unsigned num)
static void draw_custom(int y, int back_cursor, bool is_full)
{
if (y > 0) /* up y lines */
- printf(ESC"[%uA", y);
- bb_putchar('\r');
+ fprintf(stderr, ESC"[%uA", y);
+ bb_putchar_stderr('\r');
put_prompt_custom(is_full);
put_till_end_and_adv_cursor();
- printf(SEQ_CLEAR_TILL_END_OF_SCREEN);
+ fputs(SEQ_CLEAR_TILL_END_OF_SCREEN, stderr);
input_backward(back_cursor);
}
@@ -649,7 +652,7 @@ static void input_delete(int save)
command_len--;
put_till_end_and_adv_cursor();
/* Last char is still visible, erase it (and more) */
- printf(SEQ_CLEAR_TILL_END_OF_SCREEN);
+ fputs(SEQ_CLEAR_TILL_END_OF_SCREEN, stderr);
input_backward(cursor - j); /* back to old pos cursor */
}
@@ -984,8 +987,8 @@ static void remove_chunk(int16_t *int_buf, int beg, int end)
if (dbg_bmp) {
int i;
for (i = 0; int_buf[i]; i++)
- bb_putchar((unsigned char)int_buf[i]);
- bb_putchar('\n');
+ bb_putchar_stderr((unsigned char)int_buf[i]);
+ bb_putchar_stderr('\n');
}
}
/* Caller ensures that match_buf points to a malloced buffer
@@ -1162,7 +1165,7 @@ static void showfiles(void)
int nc;
for (nc = 1; nc < ncols && n+nrows < nfiles; n += nrows, nc++) {
- printf("%s%-*s", matches[n],
+ fprintf(stderr, "%s%-*s", matches[n],
(int)(column_width - unicode_strwidth(matches[n])), ""
);
}
@@ -1460,7 +1463,7 @@ void FAST_FUNC show_history(const line_input_t *st)
if (!st)
return;
for (i = 0; i < st->cnt_history; i++)
- printf("%4d %s\n", i, st->history[i]);
+ fprintf(stderr, "%4d %s\n", i, st->history[i]);
}
# if ENABLE_FEATURE_EDITING_SAVEHISTORY
@@ -1900,7 +1903,7 @@ static void ask_terminal(void)
pfd.events = POLLIN;
if (safe_poll(&pfd, 1, 0) == 0) {
S.sent_ESC_br6n = 1;
- fputs_stdout(ESC"[6n");
+ fputs(ESC"[6n", stderr);
fflush_all(); /* make terminal see it ASAP! */
}
}
@@ -2639,13 +2642,13 @@ int FAST_FUNC read_line_input(line_input_t *st, const char *prompt, char *comman
/* Control-k -- clear to end of line */
command_ps[cursor] = BB_NUL;
command_len = cursor;
- printf(SEQ_CLEAR_TILL_END_OF_SCREEN);
+ fputs(SEQ_CLEAR_TILL_END_OF_SCREEN, stderr);
break;
case CTRL('L'):
vi_case(CTRL('L')|VI_CMDMODE_BIT:)
/* Control-l -- clear screen */
/* cursor to top,left; clear to the end of screen */
- printf(ESC"[H" ESC"[J");
+ fputs(ESC"[H" ESC"[J", stderr);
draw_full(command_len - cursor);
break;
#if MAX_HISTORY > 0
@@ -2832,8 +2835,8 @@ int FAST_FUNC read_line_input(line_input_t *st, const char *prompt, char *comman
beep();
} else {
command_ps[cursor] = ic;
- bb_putchar(ic);
- bb_putchar('\b');
+ bb_putchar_stderr(ic);
+ bb_putchar_stderr('\b');
}
break;
case '\x1b': /* ESC */
@@ -3027,7 +3030,10 @@ int FAST_FUNC read_line_input(line_input_t *st, const char *prompt, char *comman
#undef read_line_input
int FAST_FUNC read_line_input(const char* prompt, char* command, int maxsize)
{
- fputs_stdout(prompt);
+ /* https://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html
+ * says that shells must write $PSn to stderr, not stdout.
+ */
+ fputs(prompt, stderr);
fflush_all();
if (!fgets(command, maxsize, stdin))
return -1;
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