lineedit: do not hang on error, but return error indicator.

[oweals/busybox.git] / libbb / read_key.c

diff --git a/libbb/read_key.c b/libbb/read_key.c
index ec1b3a4a846b4c390312086682265bda2d1e6283..840325c99e99edaa6fc8bf9268269b48f04241f3 100644 (file)
--- a/libbb/read_key.c
+++ b/libbb/read_key.c
@@ -5,11 +5,11 @@
  * Copyright (C) 2008 Rob Landley <rob@landley.net>
  * Copyright (C) 2008 Denys Vlasenko <vda.linux@googlemail.com>
  *
- * Licensed under GPL version 2, see file LICENSE in this tarball for details.
+ * Licensed under GPLv2, see file LICENSE in this source tree.
  */
 #include "libbb.h"
 
-int64_t FAST_FUNC read_key(int fd, char *buffer)
+int64_t FAST_FUNC read_key(int fd, char *buffer, int timeout)
 {
        struct pollfd pfd;
        const char *seq;
@@ -90,14 +90,27 @@ int64_t FAST_FUNC read_key(int fd, char *buffer)
                /* ESC [ Z - Shift-Tab */
        };
 
+       pfd.fd = fd;
+       pfd.events = POLLIN;
+
        buffer++; /* saved chars counter is in buffer[-1] now */
 
  start_over:
        errno = 0;
        n = (unsigned char)buffer[-1];
        if (n == 0) {
-               /* If no data, block waiting for input.
-                * It is tempting to read more than one byte here,
+               /* If no data, wait for input.
+                * If requested, wait TIMEOUT ms. TIMEOUT = -1 is useful
+                * if fd can be in non-blocking mode.
+                */
+               if (timeout >= -1) {
+                       if (safe_poll(&pfd, 1, timeout) == 0) {
+                               /* Timed out */
+                               errno = EAGAIN;
+                               return -1;
+                       }
+               }
+               /* It is tempting to read more than one byte here,
                 * but it breaks pasting. Example: at shell prompt,
                 * user presses "c","a","t" and then pastes "\nline\n".
                 * When we were reading 3 bytes here, we were eating
@@ -121,8 +134,6 @@ int64_t FAST_FUNC read_key(int fd, char *buffer)
        }
 
        /* Loop through known ESC sequences */
-       pfd.fd = fd;
-       pfd.events = POLLIN;
        seq = esccmds;
        while (*seq != '\0') {
                /* n - position in sequence we did not read yet */
@@ -202,6 +213,31 @@ int64_t FAST_FUNC read_key(int fd, char *buffer)
                        break;
                }
                n++;
+               /* Try to decipher "ESC [ NNN ; NNN R" sequence */
+               if ((ENABLE_FEATURE_EDITING_ASK_TERMINAL || ENABLE_FEATURE_VI_ASK_TERMINAL)
+                && n >= 5
+                && buffer[0] == '['
+                && buffer[n-1] == 'R'
+                && isdigit(buffer[1])
+               ) {
+                       char *end;
+                       unsigned long row, col;
+
+                       row = strtoul(buffer + 1, &end, 10);
+                       if (*end != ';' || !isdigit(end[1]))
+                               continue;
+                       col = strtoul(end + 1, &end, 10);
+                       if (*end != 'R')
+                               continue;
+                       if (row < 1 || col < 1 || (row | col) > 0x7fff)
+                               continue;
+
+                       buffer[-1] = 0;
+                       /* Pack into "1 <row15bits> <col16bits>" 32-bit sequence */
+                       col |= (((-1 << 15) | row) << 16);
+                       /* Return it in high-order word */
+                       return ((int64_t) col << 32) | (uint32_t)KEYCODE_CURSOR_POS;
+               }
        }
  got_all:
 
@@ -213,34 +249,6 @@ int64_t FAST_FUNC read_key(int fd, char *buffer)
                return 27;
        }
 
-       /* Try to decipher "ESC [ NNN ; NNN R" sequence */
-       if (ENABLE_FEATURE_EDITING_ASK_TERMINAL
-        && n >= 5
-        && buffer[0] == '['
-        && isdigit(buffer[1])
-        && buffer[n-1] == 'R'
-       ) {
-               char *end;
-               unsigned long row, col;
-
-               row = strtoul(buffer + 1, &end, 10);
-               if (*end != ';' || !isdigit(end[1]))
-                       goto not_R;
-               col = strtoul(end + 1, &end, 10);
-               if (*end != 'R')
-                       goto not_R;
-               if (row < 1 || col < 1 || (row | col) > 0x7fff)
-                       goto not_R;
-
-               buffer[-1] = 0;
-
-               /* Pack into "1 <row15bits> <col16bits>" 32-bit sequence */
-               col |= (((-1 << 15) | row) << 16);
-               /* Return it in high-order word */
-               return ((int64_t) col << 32) | (uint32_t)KEYCODE_CURSOR_POS;
-       }
- not_R:
-
        /* We were doing "buffer[-1] = n; return c;" here, but this results
         * in unknown key sequences being interpreted as ESC + garbage.
         * This was not useful. Pretend there was no key pressed,
@@ -249,3 +257,12 @@ int64_t FAST_FUNC read_key(int fd, char *buffer)
        buffer[-1] = 0;
        goto start_over;
 }
+
+void FAST_FUNC read_key_ungets(char *buffer, const char *str, unsigned len)
+{
+       unsigned cur_len = (unsigned char)buffer[0];
+       if (len > KEYCODE_BUFFER_SIZE-1 - cur_len)
+               len = KEYCODE_BUFFER_SIZE-1 - cur_len;
+       memcpy(buffer + 1 + cur_len, str, len);
+       buffer[0] += len;
+}