From 4b7db4f2ca232c630e334fa56b1eb89848d5fcc5 Mon Sep 17 00:00:00 2001 From: Denys Vlasenko Date: Fri, 29 May 2009 10:39:06 +0200 Subject: [PATCH] read_key: drop optimization where we read 3 bytes at once Signed-off-by: Denys Vlasenko --- include/libbb.h | 96 ++++++++++++++++++++++++------------------------ libbb/lineedit.c | 11 ++++-- libbb/read_key.c | 13 ++++--- shell/hush.c | 4 +- 4 files changed, 65 insertions(+), 59 deletions(-) diff --git a/include/libbb.h b/include/libbb.h index 788140d14..963e2af28 100644 --- a/include/libbb.h +++ b/include/libbb.h @@ -933,54 +933,6 @@ void bb_displayroutes(int noresolve, int netstatfmt) FAST_FUNC; #endif -/* "Keycodes" that report an escape sequence. - * We use something which fits into signed char, - * yet doesn't represent any valid Unicode characher. - * Also, -1 is reserved for error indication and we don't use it. */ -enum { - KEYCODE_UP = -2, - KEYCODE_DOWN = -3, - KEYCODE_RIGHT = -4, - KEYCODE_LEFT = -5, - KEYCODE_HOME = -6, - KEYCODE_END = -7, - KEYCODE_INSERT = -8, - KEYCODE_DELETE = -9, - KEYCODE_PAGEUP = -10, - KEYCODE_PAGEDOWN = -11, -#if 0 - KEYCODE_FUN1 = -12, - KEYCODE_FUN2 = -13, - KEYCODE_FUN3 = -14, - KEYCODE_FUN4 = -15, - KEYCODE_FUN5 = -16, - KEYCODE_FUN6 = -17, - KEYCODE_FUN7 = -18, - KEYCODE_FUN8 = -19, - KEYCODE_FUN9 = -20, - KEYCODE_FUN10 = -21, - KEYCODE_FUN11 = -22, - KEYCODE_FUN12 = -23, -#endif - KEYCODE_CURSOR_POS = -0x100, - /* How long is the longest ESC sequence we know? - * We want it big enough to be able to contain - * cursor position sequence "ESC [ 9999 ; 9999 R" - */ - KEYCODE_BUFFER_SIZE = 16 -}; -/* Note: fd may be in blocking or non-blocking mode, both make sense. - * For one, less uses non-blocking mode. - * Only the first read syscall inside read_key may block indefinitely - * (unless fd is in non-blocking mode), - * subsequent reads will time out after a few milliseconds. - * Return of -1 means EOF or error (errno == 0 on EOF). - * buffer[0] is used as a counter of buffered chars and must be 0 - * on first call. - */ -int64_t read_key(int fd, char *buffer) FAST_FUNC; - - /* Networking */ int create_icmp_socket(void) FAST_FUNC; int create_icmp6_socket(void) FAST_FUNC; @@ -1209,6 +1161,54 @@ unsigned long long bb_makedev(unsigned int major, unsigned int minor) FAST_FUNC; #endif +/* "Keycodes" that report an escape sequence. + * We use something which fits into signed char, + * yet doesn't represent any valid Unicode characher. + * Also, -1 is reserved for error indication and we don't use it. */ +enum { + KEYCODE_UP = -2, + KEYCODE_DOWN = -3, + KEYCODE_RIGHT = -4, + KEYCODE_LEFT = -5, + KEYCODE_HOME = -6, + KEYCODE_END = -7, + KEYCODE_INSERT = -8, + KEYCODE_DELETE = -9, + KEYCODE_PAGEUP = -10, + KEYCODE_PAGEDOWN = -11, +#if 0 + KEYCODE_FUN1 = -12, + KEYCODE_FUN2 = -13, + KEYCODE_FUN3 = -14, + KEYCODE_FUN4 = -15, + KEYCODE_FUN5 = -16, + KEYCODE_FUN6 = -17, + KEYCODE_FUN7 = -18, + KEYCODE_FUN8 = -19, + KEYCODE_FUN9 = -20, + KEYCODE_FUN10 = -21, + KEYCODE_FUN11 = -22, + KEYCODE_FUN12 = -23, +#endif + KEYCODE_CURSOR_POS = -0x100, + /* How long is the longest ESC sequence we know? + * We want it big enough to be able to contain + * cursor position sequence "ESC [ 9999 ; 9999 R" + */ + KEYCODE_BUFFER_SIZE = 16 +}; +/* Note: fd may be in blocking or non-blocking mode, both make sense. + * For one, less uses non-blocking mode. + * Only the first read syscall inside read_key may block indefinitely + * (unless fd is in non-blocking mode), + * subsequent reads will time out after a few milliseconds. + * Return of -1 means EOF or error (errno == 0 on EOF). + * buffer[0] is used as a counter of buffered chars and must be 0 + * on first call. + */ +int64_t read_key(int fd, char *buffer) FAST_FUNC; + + #if ENABLE_FEATURE_EDITING /* It's NOT just ENABLEd or disabled. It's a number: */ # ifdef CONFIG_FEATURE_EDITING_HISTORY diff --git a/libbb/lineedit.c b/libbb/lineedit.c index a0b1bcf8e..81f6fdeff 100644 --- a/libbb/lineedit.c +++ b/libbb/lineedit.c @@ -1451,10 +1451,13 @@ static int lineedit_read_key(char *read_key_buffer) pfd.events = POLLIN; do { poll_again: - /* Wait for input. Can't just call read_key, it will return - * at once if stdin is in non-blocking mode. */ - safe_poll(&pfd, 1, -1); - /* note: read_key sets errno to 0 on success: */ + if (read_key_buffer[0] == 0) { + /* Wait for input. Can't just call read_key, + * it returns at once if stdin + * is in non-blocking mode. */ + safe_poll(&pfd, 1, -1); + } + /* Note: read_key sets errno to 0 on success: */ ic = read_key(STDIN_FILENO, read_key_buffer); if (ENABLE_FEATURE_EDITING_ASK_TERMINAL && (int32_t)ic == KEYCODE_CURSOR_POS diff --git a/libbb/read_key.c b/libbb/read_key.c index 3771045d2..6f6c39e45 100644 --- a/libbb/read_key.c +++ b/libbb/read_key.c @@ -69,11 +69,14 @@ int64_t FAST_FUNC read_key(int fd, char *buffer) errno = 0; n = (unsigned char) *buffer++; if (n == 0) { - /* If no data, block waiting for input. If we read more - * than the minimal ESC sequence size, the "n=0" below - * would instead have to figure out how much to keep, - * resulting in larger code. */ - n = safe_read(fd, buffer, 3); + /* If no data, block waiting for input. + * 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 + * "li" too, and cat was getting wrong input. + */ + n = safe_read(fd, buffer, 1); if (n <= 0) return -1; } diff --git a/shell/hush.c b/shell/hush.c index add40eb5f..5fa693b0a 100644 --- a/shell/hush.c +++ b/shell/hush.c @@ -1006,7 +1006,7 @@ static void restore_G_args(save_arg_t *sv, char **argv) * Commands run in command substitution ("`cmd`") * have SIGTTIN, SIGTTOU, SIGTSTP set to SIG_IGN. * - * Ordinary commands have signals set to SIG_IGN/DFL set as inherited + * Ordinary commands have signals set to SIG_IGN/DFL as inherited * by the shell from its parent. * * Siganls which differ from SIG_DFL action @@ -1285,7 +1285,7 @@ static int set_local_var(char *str, int flg_export, int flg_read_only) if (strncmp(cur->varstr, str, name_len) != 0) { if (!cur->next) { /* Bail out. Note that now cur points - * to last var in linked list */ + * to the last var in the linked list */ break; } cur = cur->next;