diff options
Diffstat (limited to 'libbb/read_key.c')
| -rw-r--r-- | libbb/read_key.c | 124 |
1 files changed, 74 insertions, 50 deletions
diff --git a/libbb/read_key.c b/libbb/read_key.c index 02c381dd5..ec1b3a4a8 100644 --- a/libbb/read_key.c +++ b/libbb/read_key.c @@ -14,7 +14,6 @@ int64_t FAST_FUNC read_key(int fd, char *buffer) struct pollfd pfd; const char *seq; int n; - int c; /* Known escape sequences for cursor and function keys */ static const char esccmds[] ALIGN1 = { @@ -91,8 +90,11 @@ int64_t FAST_FUNC read_key(int fd, char *buffer) /* ESC [ Z - Shift-Tab */ }; + buffer++; /* saved chars counter is in buffer[-1] now */ + + start_over: errno = 0; - n = (unsigned char) *buffer++; + 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, @@ -106,15 +108,17 @@ int64_t FAST_FUNC read_key(int fd, char *buffer) return -1; } - /* Grab character to return from buffer */ - c = (unsigned char)buffer[0]; - n--; - if (n) - memmove(buffer, buffer + 1, n); - - /* Only ESC starts ESC sequences */ - if (c != 27) - goto ret; + { + unsigned char c = buffer[0]; + n--; + if (n) + memmove(buffer, buffer + 1, n); + /* Only ESC starts ESC sequences */ + if (c != 27) { + buffer[-1] = n; + return c; + } + } /* Loop through known ESC sequences */ pfd.fd = fd; @@ -136,17 +140,21 @@ int64_t FAST_FUNC read_key(int fd, char *buffer) if (safe_poll(&pfd, 1, 50) == 0) { /* No more data! * Array is sorted from shortest to longest, - * we can't match anything later in array, - * break out of both loops. */ - goto ret; + * we can't match anything later in array - + * anything later is longer than this seq. + * Break out of both loops. */ + goto got_all; } errno = 0; if (safe_read(fd, buffer + n, 1) <= 0) { /* If EAGAIN, then fd is O_NONBLOCK and poll lied: * in fact, there is no data. */ - if (errno != EAGAIN) - c = -1; /* otherwise it's EOF/error */ - goto ret; + if (errno != EAGAIN) { + /* otherwise: it's EOF/error */ + buffer[-1] = 0; + return -1; + } + goto got_all; } n++; } @@ -162,66 +170,82 @@ int64_t FAST_FUNC read_key(int fd, char *buffer) } if (seq[i] & 0x80) { /* Entire seq matched */ - c = (signed char)seq[i+1]; n = 0; /* n -= i; memmove(...); * would be more correct, * but we never read ahead that much, * and n == i here. */ - goto ret; + buffer[-1] = 0; + return (signed char)seq[i+1]; } i++; } } - /* We did not find matching sequence, it was a bare ESC. - * We possibly read and stored more input in buffer[] by now. */ + /* We did not find matching sequence. + * We possibly read and stored more input in buffer[] by now. + * n = bytes read. Try to read more until we time out. + */ + while (n < KEYCODE_BUFFER_SIZE-1) { /* 1 for count byte at buffer[-1] */ + if (safe_poll(&pfd, 1, 50) == 0) { + /* No more data! */ + break; + } + errno = 0; + if (safe_read(fd, buffer + n, 1) <= 0) { + /* If EAGAIN, then fd is O_NONBLOCK and poll lied: + * in fact, there is no data. */ + if (errno != EAGAIN) { + /* otherwise: it's EOF/error */ + buffer[-1] = 0; + return -1; + } + break; + } + n++; + } + got_all: + + if (n <= 1) { + /* Alt-x is usually returned as ESC x. + * Report ESC, x is remembered for the next call. + */ + buffer[-1] = n; + return 27; + } /* Try to decipher "ESC [ NNN ; NNN R" sequence */ if (ENABLE_FEATURE_EDITING_ASK_TERMINAL - && n != 0 + && n >= 5 && buffer[0] == '[' + && isdigit(buffer[1]) + && buffer[n-1] == 'R' ) { char *end; unsigned long row, col; - while (n < KEYCODE_BUFFER_SIZE-1) { /* 1 for cnt */ - if (safe_poll(&pfd, 1, 50) == 0) { - /* No more data! */ - break; - } - errno = 0; - if (safe_read(fd, buffer + n, 1) <= 0) { - /* If EAGAIN, then fd is O_NONBLOCK and poll lied: - * in fact, there is no data. */ - if (errno != EAGAIN) - c = -1; /* otherwise it's EOF/error */ - goto ret; - } - if (buffer[n++] == 'R') - goto got_R; - } - goto ret; - got_R: - if (!isdigit(buffer[1])) - goto ret; row = strtoul(buffer + 1, &end, 10); if (*end != ';' || !isdigit(end[1])) - goto ret; + goto not_R; col = strtoul(end + 1, &end, 10); if (*end != 'R') - goto ret; + goto not_R; if (row < 1 || col < 1 || (row | col) > 0x7fff) - goto ret; + goto not_R; buffer[-1] = 0; /* Pack into "1 <row15bits> <col16bits>" 32-bit sequence */ - c = (((-1 << 15) | row) << 16) | col; + col |= (((-1 << 15) | row) << 16); /* Return it in high-order word */ - return ((int64_t) c << 32) | (uint32_t)KEYCODE_CURSOR_POS; + return ((int64_t) col << 32) | (uint32_t)KEYCODE_CURSOR_POS; } + not_R: - ret: - buffer[-1] = n; - return c; + /* 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, + * go and wait for a new keypress: + */ + buffer[-1] = 0; + goto start_over; } |