line editing: add an option to emit ESC [ 6 n and use results

This makes line editing able to recognize case when
cursor was not at the beginning of the line. It may also
be adapted later to find out display size (serial line users
would love it).

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 6 insertions, 8 deletions

diff --git a/miscutils/less.c b/miscutils/less.c
index 702c4a891..bd855066f 100644
--- a/miscutils/less.c
+++ b/miscutils/less.c
@@ -96,7 +96,6 @@ struct globals {
         smallint pattern_valid;
 #endif
         smallint terminated;
-        smalluint kbd_input_size;
         struct termios term_orig, term_less;
         char kbd_input[KEYCODE_BUFFER_SIZE];
 };
@@ -135,7 +134,6 @@ struct globals {
 #define terminated          (G.terminated        )
 #define term_orig           (G.term_orig         )
 #define term_less           (G.term_less         )
-#define kbd_input_size      (G.kbd_input_size    )
 #define kbd_input           (G.kbd_input         )
 #define INIT_G() do { \
         SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
@@ -806,7 +804,7 @@ static void reinitialize(void)
         buffer_fill_and_print();
 }
 
-static ssize_t getch_nowait(void)
+static int getch_nowait(void)
 {
         int rd;
         struct pollfd pfd[2];
@@ -839,7 +837,7 @@ static ssize_t getch_nowait(void)
                 move_cursor(max_displayed_line + 2, less_gets_pos + 1);
         fflush(stdout);
 
-        if (kbd_input_size == 0) {
+        if (kbd_input[0] == 0) { /* if nothing is buffered */
 #if ENABLE_FEATURE_LESS_WINCH
                 while (1) {
                         int r;
@@ -856,7 +854,7 @@ static ssize_t getch_nowait(void)
 
         /* We have kbd_fd in O_NONBLOCK mode, read inside read_key()
          * would not block even if there is no input available */
-        rd = read_key(kbd_fd, &kbd_input_size, kbd_input);
+        rd = read_key(kbd_fd, kbd_input);
         if (rd == -1) {
                 if (errno == EAGAIN) {
                         /* No keyboard input available. Since poll() did return,
@@ -872,9 +870,9 @@ static ssize_t getch_nowait(void)
         return rd;
 }
 
-/* Grab a character from input without requiring the return key. If the
- * character is ASCII \033, get more characters and assign certain sequences
- * special return codes. Note that this function works best with raw input. */
+/* Grab a character from input without requiring the return key.
+ * May return KEYCODE_xxx values.
+ * Note that this function works best with raw input. */
 static int less_getch(int pos)
 {
         int i;