less: add optional line number toggle and resizing on SIGWINCH.

4 files changed, 108 insertions, 67 deletions

diff --git a/TODO_config_nommu b/TODO_config_nommu
index 35546897f..df51dc05a 100644
--- a/TODO_config_nommu
+++ b/TODO_config_nommu
@@ -575,7 +575,7 @@ CONFIG_LESS=y
 CONFIG_FEATURE_LESS_MAXLINES=9999999
 CONFIG_FEATURE_LESS_BRACKETS=y
 CONFIG_FEATURE_LESS_FLAGS=y
-CONFIG_FEATURE_LESS_FLAGCS=y
+CONFIG_FEATURE_LESS_DASHCMD=y
 CONFIG_FEATURE_LESS_MARKS=y
 CONFIG_FEATURE_LESS_REGEXP=y
 CONFIG_HDPARM=y
diff --git a/miscutils/Config.in b/miscutils/Config.in
index 15f677a73..40edf23a2 100644
--- a/miscutils/Config.in
+++ b/miscutils/Config.in
@@ -293,13 +293,13 @@ config FEATURE_LESS_FLAGS
           The -M flag enables a more sophisticated status line.
           The -m flag enables a simpler status line with a percentage.
 
-config FEATURE_LESS_FLAGCS
-        bool "Enable flag changes"
+config FEATURE_LESS_DASHCMD
+        bool "Enable flag changes ('-' command)"
         default n
         depends on LESS
         help
           This enables the ability to change command-line flags within
-          less itself.
+          less itself ('-' keyboard command).
 
 config FEATURE_LESS_MARKS
         bool "Enable marks"
@@ -315,6 +315,20 @@ config FEATURE_LESS_REGEXP
         help
           Enable regular expressions, allowing complex file searches.
 
+config FEATURE_LESS_LINENUMS
+        bool "Enable dynamic switching of line numbers"
+        default n
+        depends on LESS
+        help
+          Enable "-N" command.
+
+config FEATURE_LESS_WINCH
+        bool "Enable automatic resizing on window size changes"
+        default n
+        depends on LESS
+        help
+          Makes less track window size changes.
+
 config HDPARM
         bool "hdparm"
         default n
diff --git a/miscutils/less.c b/miscutils/less.c
index 1af9685bf..f367b0ebc 100644
--- a/miscutils/less.c
+++ b/miscutils/less.c
@@ -28,13 +28,6 @@
 #include "xregex.h"
 #endif
 
-/* In progress */
-#define ENABLE_FEATURE_LESS_REWRAP 0
-
-/* FIXME: currently doesn't work right */
-#undef ENABLE_FEATURE_LESS_FLAGCS
-#define ENABLE_FEATURE_LESS_FLAGCS 0
-
 /* The escape codes for highlighted and normal text */
 #define HIGHLIGHT "\033[7m"
 #define NORMAL "\033[0m"
@@ -77,14 +70,14 @@ enum {
 
 /* Command line options */
 enum {
-        FLAG_E = 1,
+        FLAG_E = 1 << 0,
         FLAG_M = 1 << 1,
         FLAG_m = 1 << 2,
         FLAG_N = 1 << 3,
         FLAG_TILDE = 1 << 4,
         FLAG_I = 1 << 5,
+        FLAG_S = (1 << 6) * ENABLE_FEATURE_LESS_DASHCMD,
 /* hijack command line options variable for internal state vars */
-        LESS_STATE_NO_WRAP = 1 << 14,
         LESS_STATE_MATCH_BACKWARDS = 1 << 15,
 };
 
@@ -98,10 +91,13 @@ struct globals {
         int less_gets_pos;
 /* last position in last line, taking into account tabs */
         size_t linepos;
-        unsigned max_displayed_line;
         unsigned max_fline;
         unsigned max_lineno; /* this one tracks linewrap */
+        unsigned max_displayed_line;
         unsigned width;
+#if ENABLE_FEATURE_LESS_WINCH
+        unsigned winch_counter;
+#endif
         ssize_t eof_error; /* eof if 0, error if < 0 */
         ssize_t readpos;
         ssize_t readeof; /* must be signed */
@@ -132,10 +128,11 @@ struct globals {
 #define kbd_fd              (G.kbd_fd            )
 #define less_gets_pos       (G.less_gets_pos     )
 #define linepos             (G.linepos           )
-#define max_displayed_line  (G.max_displayed_line)
 #define max_fline           (G.max_fline         )
 #define max_lineno          (G.max_lineno        )
+#define max_displayed_line  (G.max_displayed_line)
 #define width               (G.width             )
+#define winch_counter       (G.winch_counter     )
 #define eof_error           (G.eof_error         )
 #define readpos             (G.readpos           )
 #define readeof             (G.readeof           )
@@ -218,7 +215,7 @@ static void less_exit(int code)
         exit(code);
 }
 
-#if ENABLE_FEATURE_LESS_REWRAP
+#if ENABLE_FEATURE_LESS_LINENUMS || ENABLE_FEATURE_LESS_WINCH
 static void re_wrap(void)
 {
         int w = width;
@@ -297,6 +294,7 @@ static void re_wrap(void)
         linepos = 0; // XXX
         cur_fline = new_cur_fline;
         /* max_lineno is screen-size independent */
+        pattern_valid = 0;
 }
 #endif
 
@@ -426,7 +424,11 @@ static void read_lines(void)
                         eof_error = 0; /* Pretend we saw EOF */
                         break;
                 }
-                if (max_fline > cur_fline + max_displayed_line) {
+                if (!(option_mask32 & FLAG_S)
+                  ? (max_fline > cur_fline + max_displayed_line)
+                  : (max_fline >= cur_fline
+                     && max_lineno > LINENO(flines[cur_fline]) + max_displayed_line)
+                ) {
 #if !ENABLE_FEATURE_LESS_REGEXP
                         break;
 #else
@@ -719,18 +721,19 @@ static void buffer_print(void)
         status_print();
 }
 
-#if ENABLE_FEATURE_LESS_REWRAP
 static void buffer_fill_and_print(void)
 {
-        unsigned i = 0;
-        int fpos = cur_fline + i;
+        unsigned i;
+#if ENABLE_FEATURE_LESS_DASHCMD
+        int fpos = cur_fline;
 
-        if (option_mask32 & LESS_STATE_NO_WRAP) {
+        if (option_mask32 & FLAG_S) {
                 /* Go back to the beginning of this line */
                 while (fpos && LINENO(flines[fpos]) == LINENO(flines[fpos-1]))
                         fpos--;
         }
 
+        i = 0;
         while (i <= max_displayed_line && fpos <= max_fline) {
                 int lineno = LINENO(flines[fpos]);
                 buffer[i] = flines[fpos];
@@ -738,28 +741,20 @@ static void buffer_fill_and_print(void)
                 do {
                         fpos++;
                 } while ((fpos <= max_fline)
-                      && (option_mask32 & LESS_STATE_NO_WRAP)
+                      && (option_mask32 & FLAG_S)
                       && lineno == LINENO(flines[fpos])
                 );
         }
-        for (; i <= max_displayed_line; i++) {
-                buffer[i] = empty_line_marker;
-        }
-        buffer_print();
-}
 #else
-static void buffer_fill_and_print(void)
-{
-        unsigned i;
         for (i = 0; i <= max_displayed_line && cur_fline + i <= max_fline; i++) {
                 buffer[i] = flines[cur_fline + i];
         }
+#endif
         for (; i <= max_displayed_line; i++) {
                 buffer[i] = empty_line_marker;
         }
         buffer_print();
 }
-#endif
 
 /* Move the buffer up and down in the file in order to scroll */
 static void buffer_down(int nlines)
@@ -857,7 +852,19 @@ static ssize_t getch_nowait(char* input, int sz)
         if (less_gets_pos >= 0)
                 move_cursor(max_displayed_line + 2, less_gets_pos + 1);
         fflush(stdout);
+#if ENABLE_FEATURE_LESS_WINCH
+        while (1) {
+                int r;
+                r = poll(pfd + rd, 2 - rd, -1);
+                if (/*r < 0 && errno == EINTR &&*/ winch_counter) {
+                        input[0] = '\\'; /* anything which has no defined function */
+                        return 1;
+                }
+                if (r) break;
+        }
+#else
         safe_poll(pfd + rd, 2 - rd, -1);
+#endif
 
         input[0] = '\0';
         rd = safe_read(kbd_fd, input, sz); /* NB: kbd_fd is in O_NONBLOCK mode */
@@ -1114,7 +1121,7 @@ static void regex_process(void)
 
         /* Compile the regex and check for errors */
         err = regcomp_or_errmsg(&pattern, uncomp_regex,
-                                                        option_mask32 & FLAG_I ? REG_ICASE : 0);
+                                (option_mask32 & FLAG_I) ? REG_ICASE : 0);
         free(uncomp_regex);
         if (err) {
                 print_statusline(err);
@@ -1208,7 +1215,7 @@ static void number_process(int first_digit)
         }
 }
 
-#if ENABLE_FEATURE_LESS_FLAGCS
+#if ENABLE_FEATURE_LESS_DASHCMD
 static void flag_change(void)
 {
         int keypress;
@@ -1230,6 +1237,17 @@ static void flag_change(void)
         case '~':
                 option_mask32 ^= FLAG_TILDE;
                 break;
+        case 'S':
+                option_mask32 ^= FLAG_S;
+                buffer_fill_and_print();
+                break;
+#if ENABLE_FEATURE_LESS_LINENUMS
+        case 'N':
+                option_mask32 ^= FLAG_N;
+                re_wrap();
+                buffer_fill_and_print();
+                break;
+#endif
         }
 }
 
@@ -1467,7 +1485,7 @@ static void keypress_process(int keypress)
                 regex_process();
                 break;
 #endif
-#if ENABLE_FEATURE_LESS_FLAGCS
+#if ENABLE_FEATURE_LESS_DASHCMD
         case '-':
                 flag_change();
                 buffer_print();
@@ -1487,25 +1505,6 @@ static void keypress_process(int keypress)
         case ':':
                 colon_process();
                 break;
-#if ENABLE_FEATURE_LESS_REWRAP
-        case '*': /* Should be -N command / option */
-                option_mask32 ^= FLAG_N;
-                get_terminal_width_height(kbd_fd, &width, &max_displayed_line);
-                if (width < 20) /* 20: two tabstops + 4 */
-                        width = 20;
-                if (max_displayed_line < 3)
-                        max_displayed_line = 3;
-                max_displayed_line -= 2;
-                free(buffer);
-                buffer = xmalloc((max_displayed_line+1) * sizeof(char *));
-                re_wrap();
-                buffer_fill_and_print();
-                break;
-        case '&': /* Should be -S command / option */
-                option_mask32 ^= LESS_STATE_NO_WRAP;
-                buffer_fill_and_print();
-                break;
-#endif
         }
 
         if (isdigit(keypress))
@@ -1517,6 +1516,13 @@ static void sig_catcher(int sig)
         less_exit(- sig);
 }
 
+#if ENABLE_FEATURE_LESS_WINCH
+static void sigwinch_handler(int sig UNUSED_PARAM)
+{
+        winch_counter++;
+}
+#endif
+
 int less_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int less_main(int argc, char **argv)
 {
@@ -1527,7 +1533,7 @@ int less_main(int argc, char **argv)
         /* TODO: -x: do not interpret backspace, -xx: tab also */
         /* -xxx: newline also */
         /* -w N: assume width N (-xxx -w 32: hex viewer of sorts) */
-        getopt32(argv, "EMmN~I");
+        getopt32(argv, "EMmN~I" USE_FEATURE_LESS_DASHCMD("S"));
         argc -= optind;
         argv += optind;
         num_files = argc;
@@ -1537,10 +1543,6 @@ int less_main(int argc, char **argv)
          * is not a tty and turns into cat. This makes sense. */
         if (!isatty(STDOUT_FILENO))
                 return bb_cat(argv);
-        kbd_fd = open(CURRENT_TTY, O_RDONLY);
-        if (kbd_fd < 0)
-                return bb_cat(argv);
-        ndelay_on(kbd_fd);
 
         if (!num_files) {
                 if (isatty(STDIN_FILENO)) {
@@ -1548,19 +1550,18 @@ int less_main(int argc, char **argv)
                         bb_error_msg("missing filename");
                         bb_show_usage();
                 }
-        } else
+        } else {
                 filename = xstrdup(files[0]);
+        }
 
-        get_terminal_width_height(kbd_fd, &width, &max_displayed_line);
-        /* 20: two tabstops + 4 */
-        if (width < 20 || max_displayed_line < 3)
-                return bb_cat(argv);
-        max_displayed_line -= 2;
-
-        buffer = xmalloc((max_displayed_line+1) * sizeof(char *));
         if (option_mask32 & FLAG_TILDE)
                 empty_line_marker = "";
 
+        kbd_fd = open(CURRENT_TTY, O_RDONLY);
+        if (kbd_fd < 0)
+                return bb_cat(argv);
+        ndelay_on(kbd_fd);
+
         tcgetattr(kbd_fd, &term_orig);
         term_less = term_orig;
         term_less.c_lflag &= ~(ICANON | ECHO);
@@ -1569,11 +1570,37 @@ int less_main(int argc, char **argv)
         term_less.c_cc[VMIN] = 1;
         term_less.c_cc[VTIME] = 0;
 
+        get_terminal_width_height(kbd_fd, &width, &max_displayed_line);
+        /* 20: two tabstops + 4 */
+        if (width < 20 || max_displayed_line < 3)
+                return bb_cat(argv);
+        max_displayed_line -= 2;
+
         /* We want to restore term_orig on exit */
         bb_signals(BB_FATAL_SIGS, sig_catcher);
+#if ENABLE_FEATURE_LESS_WINCH
+        signal(SIGWINCH, sigwinch_handler);
+#endif
 
+        buffer = xmalloc((max_displayed_line+1) * sizeof(char *));
         reinitialize();
         while (1) {
+#if ENABLE_FEATURE_LESS_WINCH
+                if (winch_counter) {
+                        winch_counter--;
+                        get_terminal_width_height(kbd_fd, &width, &max_displayed_line);
+                        /* 20: two tabstops + 4 */
+                        if (width < 20)
+                                width = 20;
+                        if (max_displayed_line < 3)
+                                max_displayed_line = 3;
+                        max_displayed_line -= 2;
+                        free(buffer);
+                        buffer = xmalloc((max_displayed_line+1) * sizeof(char *));
+                        re_wrap();
+                        buffer_fill_and_print();
+                }
+#endif
                 keypress = less_getch(-1); /* -1: do not position cursor */
                 keypress_process(keypress);
         }
diff --git a/scripts/defconfig b/scripts/defconfig
index dc926c8e0..5a5a23fb6 100644
--- a/scripts/defconfig
+++ b/scripts/defconfig
@@ -573,7 +573,7 @@ CONFIG_LESS=y
 CONFIG_FEATURE_LESS_MAXLINES=9999999
 CONFIG_FEATURE_LESS_BRACKETS=y
 CONFIG_FEATURE_LESS_FLAGS=y
-CONFIG_FEATURE_LESS_FLAGCS=y
+CONFIG_FEATURE_LESS_DASHCMD=y
 CONFIG_FEATURE_LESS_MARKS=y
 CONFIG_FEATURE_LESS_REGEXP=y
 CONFIG_HDPARM=y