vi: improved handling of backspace in replace mode

In replace mode ('R' command) the backspace character should get
special treatment:

- backspace only goes back to the start of the replacement;
- backspacing over replaced characters restores the original text.

Prior to this commit BusyBox vi deleted the characters both before
and after the cursor in replace mode.

function                                             old     new   delta
undo_pop                                               -     235    +235
char_insert                                          858     884     +26
indicate_error                                        81      84      +3
find_range                                           654     657      +3
static.text_yank                                      77      79      +2
do_cmd                                              4486    4243    -243
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 4/1 up/down: 269/-243)           Total: 26 bytes

Signed-off-by: Ron Yorston <rmy@pobox.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Ron Yorston 2022-03-03 11:35:46 +00:00 committed by Denys Vlasenko
parent 55f969a006
commit fc7868602e

View File

@ -224,6 +224,7 @@
#endif #endif
#define isbackspace(c) ((c) == term_orig.c_cc[VERASE] || (c) == 8 || (c) == 127)
enum { enum {
MAX_TABSTOP = 32, // sanity limit MAX_TABSTOP = 32, // sanity limit
@ -342,6 +343,7 @@ struct globals {
int last_modified_count; // = -1; int last_modified_count; // = -1;
int cmdline_filecnt; // how many file names on cmd line int cmdline_filecnt; // how many file names on cmd line
int cmdcnt; // repetition count int cmdcnt; // repetition count
char *rstart; // start of text in Replace mode
unsigned rows, columns; // the terminal screen is this size unsigned rows, columns; // the terminal screen is this size
#if ENABLE_FEATURE_VI_ASK_TERMINAL #if ENABLE_FEATURE_VI_ASK_TERMINAL
int get_rowcol_error; int get_rowcol_error;
@ -474,6 +476,7 @@ struct globals {
#define last_modified_count (G.last_modified_count) #define last_modified_count (G.last_modified_count)
#define cmdline_filecnt (G.cmdline_filecnt ) #define cmdline_filecnt (G.cmdline_filecnt )
#define cmdcnt (G.cmdcnt ) #define cmdcnt (G.cmdcnt )
#define rstart (G.rstart )
#define rows (G.rows ) #define rows (G.rows )
#define columns (G.columns ) #define columns (G.columns )
#define crow (G.crow ) #define crow (G.crow )
@ -1212,7 +1215,7 @@ static char *get_input_line(const char *prompt)
c = get_one_char(); c = get_one_char();
if (c == '\n' || c == '\r' || c == 27) if (c == '\n' || c == '\r' || c == 27)
break; // this is end of input break; // this is end of input
if (c == term_orig.c_cc[VERASE] || c == 8 || c == 127) { if (isbackspace(c)) {
// user wants to erase prev char // user wants to erase prev char
write1("\b \b"); // erase char on screen write1("\b \b"); // erase char on screen
buf[--i] = '\0'; buf[--i] = '\0';
@ -2174,8 +2177,16 @@ static char *char_insert(char *p, char c, int undo) // insert the char c at 'p'
p += 1 + stupid_insert(p, ' '); p += 1 + stupid_insert(p, ' ');
} }
#endif #endif
} else if (c == term_orig.c_cc[VERASE] || c == 8 || c == 127) { // Is this a BS } else if (isbackspace(c)) {
if (p > text) { if (cmd_mode == 2) {
// special treatment for backspace in Replace mode
if (p > rstart) {
p--;
#if ENABLE_FEATURE_VI_UNDO
undo_pop();
#endif
}
} else if (p > text) {
p--; p--;
p = text_hole_delete(p, p, ALLOW_UNDO_QUEUED); // shrink buffer 1 char p = text_hole_delete(p, p, ALLOW_UNDO_QUEUED); // shrink buffer 1 char
} }
@ -3703,9 +3714,9 @@ static void do_cmd(int c)
undo_queue_commit(); undo_queue_commit();
} else { } else {
if (1 <= c || Isprint(c)) { if (1 <= c || Isprint(c)) {
if (c != 27) if (c != 27 && !isbackspace(c))
dot = yank_delete(dot, dot, PARTIAL, YANKDEL, ALLOW_UNDO); // delete char dot = yank_delete(dot, dot, PARTIAL, YANKDEL, ALLOW_UNDO);
dot = char_insert(dot, c, ALLOW_UNDO_CHAIN); // insert new char dot = char_insert(dot, c, ALLOW_UNDO_CHAIN);
} }
goto dc1; goto dc1;
} }
@ -4264,6 +4275,7 @@ static void do_cmd(int c)
dc5: dc5:
cmd_mode = 2; cmd_mode = 2;
undo_queue_commit(); undo_queue_commit();
rstart = dot;
break; break;
case KEYCODE_DELETE: case KEYCODE_DELETE:
if (dot < end - 1) if (dot < end - 1)