lineedit: move console viewport to cursor on keypress

When a normal *nix terminal has been scrolled back through its
buffer, any keypress will return to the cursor position.  Add code
to lineedit.c to do the same for the Windows console.

3 files changed, 7 insertions, 1 deletions

diff --git a/include/mingw.h b/include/mingw.h
index f30338ba8..5faef41bf 100644
--- a/include/mingw.h
+++ b/include/mingw.h
@@ -154,6 +154,7 @@ int mingw_pclose(FILE *fd);
  * ANSI emulation wrappers
  */
 
+void move_cursor_row(int n);
 int winansi_putchar(int c);
 int winansi_puts(const char *s);
 size_t winansi_fwrite(const void *ptr, size_t size, size_t nmemb, FILE *stream);
diff --git a/libbb/lineedit.c b/libbb/lineedit.c
index 04361b509..e7b9ddfa1 100644
--- a/libbb/lineedit.c
+++ b/libbb/lineedit.c
@@ -2440,6 +2440,11 @@ int FAST_FUNC read_line_input(line_input_t *st, const char *prompt, char *comman
 
                 fflush_all();
                 ic = ic_raw = lineedit_read_key(read_key_buffer, timeout);
+#if ENABLE_PLATFORM_MINGW32
+                /* scroll to cursor position on any keypress */
+                if (isatty(fileno(stdin)) && isatty(fileno(stdout)))
+                        move_cursor_row(0);
+#endif
 
 #if ENABLE_FEATURE_REVERSE_SEARCH
  again:
diff --git a/win32/winansi.c b/win32/winansi.c
index 5d4adbec8..ebe831593 100644
--- a/win32/winansi.c
+++ b/win32/winansi.c
@@ -125,7 +125,7 @@ static void erase_till_end_of_screen(void)
 
 }
 
-static void move_cursor_row(int n)
+void move_cursor_row(int n)
 {
         CONSOLE_SCREEN_BUFFER_INFO sbi;