lineedit: fix handling of repeating Alt-b, Alt-f, Alt-d, Alt-Backspace

These key combinations should repeat correctly when the keys are
pressed and held.

Before this change, they do this erratically - many repeats are "eaten"
because they are treated as unrecognized ESC seqs:
ESC 0x7f is treated by Alt+baskspace, but ESC 0x7f ESC 0x7f ESC 0x7f
is unrecognized.

Escape sequences corresponding to these key combinations are moved from
read_line_input to lineedit_read_key.

Also, these key sequences are now enabled regardless of whether
FEATURE_EDITING_VI is set, since Vim does not actually support these key
combinations, but they are present in readline library.

function                                             old     new   delta
static.esccmds                                        93     103     +10
read_line_input                                     3737    3687     -50

Signed-off-by: Rostislav Skudnov <rostislav@tuxera.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

2 files changed, 30 insertions, 42 deletions

diff --git a/libbb/lineedit.c b/libbb/lineedit.c
index 2cc61db..ac049f5 100644
--- a/libbb/lineedit.c
+++ b/libbb/lineedit.c
@@ -13,7 +13,6 @@
  *
  * This code is 'as is' with no warranty.
  */
-
 /*
  * Usage and known bugs:
  * Terminal key codes are not extensive, more needs to be added.
@@ -23,9 +22,6 @@
  * Ctrl-E also works as End.
  *
  * The following readline-like commands are not implemented:
- * ESC-b -- Move back one word
- * ESC-f -- Move forward one word
- * ESC-d -- Delete forward one word
  * CTL-t -- Transpose two characters
  *
  * lineedit does not know that the terminal escape sequences do not
@@ -2483,6 +2479,24 @@ int FAST_FUNC read_line_input(line_input_t *st, const char *prompt, char *comman
 			while (cursor > 0 && !BB_isspace(command_ps[cursor-1]))
 				input_backspace();
 			break;
+		case KEYCODE_ALT_D: {
+			/* Delete word forward */
+			int nc, sc = cursor;
+			ctrl_right();
+			nc = cursor - sc;
+			input_backward(nc);
+			while (--nc >= 0)
+				input_delete(1);
+			break;
+		}
+		case KEYCODE_ALT_BACKSPACE: {
+			/* Delete word backward */
+			int sc = cursor;
+			ctrl_left();
+			while (sc-- > cursor)
+				input_delete(1);
+			break;
+		}
 #if ENABLE_FEATURE_REVERSE_SEARCH
 		case CTRL('R'):
 			ic = ic_raw = reverse_i_search();
@@ -2625,44 +2639,6 @@ int FAST_FUNC read_line_input(line_input_t *st, const char *prompt, char *comman
 				vi_cmdmode = 1;
 				input_backward(1);
 			}
-			/* Handle a few ESC-<key> combinations the same way
-			 * standard readline bindings (IOW: bash) do.
-			 * Often, Alt-<key> generates ESC-<key>.
-			 */
-			ic = lineedit_read_key(read_key_buffer, 50);
-			switch (ic) {
-				//case KEYCODE_LEFT: - bash doesn't do this
-				case 'b':
-					ctrl_left();
-					break;
-				//case KEYCODE_RIGHT: - bash doesn't do this
-				case 'f':
-					ctrl_right();
-					break;
-				//case KEYCODE_DELETE: - bash doesn't do this
-				case 'd':  /* Alt-D */
-				{
-					/* Delete word forward */
-					int nc, sc = cursor;
-					ctrl_right();
-					nc = cursor - sc;
-					input_backward(nc);
-					while (--nc >= 0)
-						input_delete(1);
-					break;
-				}
-				case '\b':   /* Alt-Backspace(?) */
-				case '\x7f': /* Alt-Backspace(?) */
-				//case 'w': - bash doesn't do this
-				{
-					/* Delete word backward */
-					int sc = cursor;
-					ctrl_left();
-					while (sc-- > cursor)
-						input_delete(1);
-					break;
-				}
-			}
 			break;
 #endif /* FEATURE_COMMAND_EDITING_VI */
 
diff --git a/libbb/read_key.c b/libbb/read_key.c
index ace23de..9517868 100644
--- a/libbb/read_key.c
+++ b/libbb/read_key.c
@@ -18,8 +18,20 @@ int64_t FAST_FUNC read_key(int fd, char *buffer, int timeout)
 	/* Known escape sequences for cursor and function keys.
 	 * See "Xterm Control Sequences"
 	 * http://invisible-island.net/xterm/ctlseqs/ctlseqs.html
+	 * Array should be sorted from shortest to longest.
 	 */
 	static const char esccmds[] ALIGN1 = {
+		'\x7f'         |0x80,KEYCODE_ALT_BACKSPACE,
+		'\b'           |0x80,KEYCODE_ALT_BACKSPACE,
+		'd'            |0x80,KEYCODE_ALT_D   ,
+	/* lineedit mimics bash: Alt-f and Alt-b are forward/backward
+	 * word jumps. We cheat here and make them return ALT_LEFT/RIGHT
+	 * keycodes. This way, lineedit need no special code to handle them.
+	 * If we'll need to distinguish them, introduce new ALT_F/B keycodes,
+	 * and update lineedit to react to them.
+	 */
+		'f'            |0x80,KEYCODE_ALT_RIGHT,
+		'b'            |0x80,KEYCODE_ALT_LEFT,
 		'O','A'        |0x80,KEYCODE_UP      ,
 		'O','B'        |0x80,KEYCODE_DOWN    ,
 		'O','C'        |0x80,KEYCODE_RIGHT   ,