vi: install SIGINT handler _after_ restart setjmp is initialized

While at it, sanitized comment style, deleted wrong ones, renamed signal
handlers to <sig>_handler(), slightly optimized "cursor home+clear screen".

function                                             old     new   delta
cont_handler                                           -      66     +66
tstp_handler                                           -      64     +64
winch_handler                                          -      60     +60
int_handler                                            -      32     +32
edit_file                                            648     651      +3
redraw                                                52      43      -9
catch_sig                                             32       -     -32
winch_sig                                             60       -     -60
suspend_sig                                           64       -     -64
cont_sig                                              66       -     -66
------------------------------------------------------------------------------
(add/remove: 4/4 grow/shrink: 1/1 up/down: 225/-231)           Total: -6 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 52 insertions, 63 deletions

diff --git a/editors/vi.c b/editors/vi.c
index 425d14c9c..a11e06040 100644
--- a/editors/vi.c
+++ b/editors/vi.c
@@ -235,9 +235,10 @@ enum {
  * Full sequence is "ESC [ <num> J",
  * <num> is 0/1/2 = "erase below/above/all".)
  */
-#define ESC_CLEAR2EOS ESC"[J"
+#define ESC_CLEAR2EOS          ESC"[J"
 /* Cursor to given coordinate (1,1: top left) */
-#define ESC_SET_CURSOR_POS ESC"[%u;%uH"
+#define ESC_SET_CURSOR_POS     ESC"[%u;%uH"
+#define ESC_SET_CURSOR_TOPLEFT ESC"[H"
 //UNUSED
 ///* Cursor up and down */
 //#define ESC_CURSOR_UP   ESC"[A"
@@ -352,7 +353,7 @@ struct globals {
         char *context_start, *context_end;
 #endif
 #if ENABLE_FEATURE_VI_USE_SIGNALS
-        sigjmp_buf restart;     // catch_sig()
+        sigjmp_buf restart;     // int_handler() jumps to location remembered here
 #endif
         struct termios term_orig; // remember what the cooked mode was
 #if ENABLE_FEATURE_VI_COLON
@@ -535,15 +536,11 @@ static void rawmode(void);	// set "raw" mode on tty
 static void cookmode(void);     // return to "cooked" mode on tty
 // sleep for 'h' 1/100 seconds, return 1/0 if stdin is (ready for read)/(not ready)
 static int mysleep(int);
-static int readit(void);        // read (maybe cursor) key from stdin
 static int get_one_char(void);  // read 1 char from stdin
 // file_insert might reallocate text[]!
 static int file_insert(const char *, char *, int);
 static int file_write(char *, char *, char *);
-static void place_cursor(int, int);
 static void screen_erase(void);
-static void clear_to_eol(void);
-static void clear_to_eos(void);
 static void go_bottom_and_clear_to_eol(void);
 static void standout_start(void);       // send "start reverse video" sequence
 static void standout_end(void); // send "end reverse video" sequence
@@ -570,9 +567,9 @@ static char *get_address(char *, int *, int *);	// get two colon addrs, if prese
 #endif
 static void colon(char *);      // execute the "colon" mode cmds
 #if ENABLE_FEATURE_VI_USE_SIGNALS
-static void winch_sig(int);     // catch window size changes
-static void suspend_sig(int);   // catch ctrl-Z
-static void catch_sig(int);     // catch ctrl-C and alarm time-outs
+static void winch_handler(int); // catch window size changes
+static void tstp_handler(int);  // catch ctrl-Z
+static void int_handler(int);   // catch ctrl-C
 #endif
 #if ENABLE_FEATURE_VI_DOT_CMD
 static void start_new_cmd_q(char);      // new queue for command
@@ -598,11 +595,11 @@ static void check_context(char);	// remember context for '' command
 #endif
 #if ENABLE_FEATURE_VI_UNDO
 static void flush_undo_data(void);
-static void undo_push(char *, unsigned int, unsigned char);     // Push an operation on the undo stack
+static void undo_push(char *, unsigned, unsigned char); // push an operation on the undo stack
 static void undo_push_insert(char *, int, int); // convenience function
-static void undo_pop(void);     // Undo the last operation
+static void undo_pop(void);             // undo the last operation
 # if ENABLE_FEATURE_VI_UNDO_QUEUE
-static void undo_queue_commit(void);    // Flush any queued objects to the undo stack
+static void undo_queue_commit(void);    // flush any queued objects to the undo stack
 # else
 # define undo_queue_commit() ((void)0)
 # endif
@@ -644,7 +641,7 @@ int vi_main(int argc, char **argv)
         srand((long) my_pid);
 #endif
 #ifdef NO_SUCH_APPLET_YET
-        /* If we aren't "vi", we are "view" */
+        // if we aren't "vi", we are "view"
         if (ENABLE_FEATURE_VI_READONLY && applet_name[2]) {
                 SET_READONLY_MODE(readonly_mode);
         }
@@ -682,7 +679,7 @@ int vi_main(int argc, char **argv)
 #endif
                 case 'H':
                         show_help();
-                        /* fall through */
+                        // fall through
                 default:
                         bb_show_usage();
                         return 1;
@@ -699,7 +696,7 @@ int vi_main(int argc, char **argv)
         // "Save cursor, use alternate screen buffer, clear screen"
         write1(ESC"[?1049h");
         while (1) {
-                edit_file(argv[optind]); /* param might be NULL */
+                edit_file(argv[optind]); // param might be NULL
                 if (++optind >= argc)
                         break;
         }
@@ -804,13 +801,15 @@ static void edit_file(char *fn)
         ccol = 0;
 
 #if ENABLE_FEATURE_VI_USE_SIGNALS
-        signal(SIGINT, catch_sig);
-        signal(SIGWINCH, winch_sig);
-        signal(SIGTSTP, suspend_sig);
+        signal(SIGWINCH, winch_handler);
+        signal(SIGTSTP, tstp_handler);
         sig = sigsetjmp(restart, 1);
         if (sig != 0) {
                 screenbegin = dot = text;
         }
+        // int_handler() can jump to "restart",
+        // must install handler *after* initializing "restart"
+        signal(SIGINT, int_handler);
 #endif
 
         cmd_mode = 0;           // 0=command  1=insert  2='R'eplace
@@ -994,7 +993,7 @@ static void setops(const char *args, const char *opname, int flg_no,
                         const char *short_opname, int opt)
 {
         const char *a = args + flg_no;
-        int l = strlen(opname) - 1; /* opname have + ' ' */
+        int l = strlen(opname) - 1; // opname have + ' '
 
         // maybe strncmp? we had tons of erroneous strncasecmp's...
         if (strncasecmp(a, opname, l) == 0
@@ -1014,7 +1013,7 @@ static void setops(const char *args, const char *opname, int flg_no,
 static void colon(char *buf)
 {
 #if !ENABLE_FEATURE_VI_COLON
-        /* Simple ":cmd" handler with minimal set of commands */
+        // Simple ":cmd" handler with minimal set of commands
         char *p = buf;
         int cnt;
 
@@ -1357,7 +1356,7 @@ static void colon(char *buf)
                         status_line_bold("No write since last change (:%s! overrides)", cmd);
                 } else {
                         // reset the filenames to edit
-                        optind = -1; /* start from 0th file */
+                        optind = -1; // start from 0th file
                         editing = 0;
                 }
 # if ENABLE_FEATURE_VI_SET
@@ -2218,7 +2217,7 @@ static char *find_pair(char *p, const char c)
         dir = strchr(braces, c) - braces;
         dir ^= 1;
         match = braces[dir];
-        dir = ((dir & 1) << 1) - 1; /* 1 for ([{, -1 for )\} */
+        dir = ((dir & 1) << 1) - 1; // 1 for ([{, -1 for )\}
 
         // look for match, count levels of pairs  (( ))
         level = 1;
@@ -2271,7 +2270,8 @@ static void flush_undo_data(void)
 }
 
 // Undo functions and hooks added by Jody Bruchon (jody@jodybruchon.com)
-static void undo_push(char *src, unsigned int length, uint8_t u_type)   // Add to the undo stack
+// Add to the undo stack
+static void undo_push(char *src, unsigned length, uint8_t u_type)
 {
         struct undo_object *undo_entry;
 
@@ -2389,7 +2389,8 @@ static void undo_push_insert(char *p, int len, int undo)
         }
 }
 
-static void undo_pop(void)      // Undo the last operation
+// Undo the last operation
+static void undo_pop(void)
 {
         int repeat;
         char *u_start, *u_end;
@@ -2453,7 +2454,8 @@ static void undo_pop(void)	// Undo the last operation
 }
 
 #if ENABLE_FEATURE_VI_UNDO_QUEUE
-static void undo_queue_commit(void)     // Flush any queued objects to the undo stack
+// Flush any queued objects to the undo stack
+static void undo_queue_commit(void)
 {
         // Pushes the queue object onto the undo stack
         if (undo_q > 0) {
@@ -2758,49 +2760,44 @@ static void cookmode(void)
 }
 
 #if ENABLE_FEATURE_VI_USE_SIGNALS
-//----- Come here when we get a window resize signal ---------
-static void winch_sig(int sig UNUSED_PARAM)
+static void winch_handler(int sig UNUSED_PARAM)
 {
         int save_errno = errno;
         // FIXME: do it in main loop!!!
-        signal(SIGWINCH, winch_sig);
+        signal(SIGWINCH, winch_handler);
         query_screen_dimensions();
         new_screen(rows, columns);      // get memory for virtual screen
         redraw(TRUE);           // re-draw the screen
         errno = save_errno;
 }
-
-//----- Come here when we get a continue signal -------------------
-static void cont_sig(int sig UNUSED_PARAM)
+static void cont_handler(int sig UNUSED_PARAM)
 {
         int save_errno = errno;
         rawmode(); // terminal to "raw"
         last_status_cksum = 0; // force status update
         redraw(TRUE); // re-draw the screen
 
-        signal(SIGTSTP, suspend_sig);
+        signal(SIGTSTP, tstp_handler);
         signal(SIGCONT, SIG_DFL);
         //kill(my_pid, SIGCONT); // huh? why? we are already "continued"...
         errno = save_errno;
 }
-
-//----- Come here when we get a Suspend signal -------------------
-static void suspend_sig(int sig UNUSED_PARAM)
+static void tstp_handler(int sig UNUSED_PARAM)
 {
         int save_errno = errno;
         go_bottom_and_clear_to_eol();
         cookmode(); // terminal to "cooked"
 
-        signal(SIGCONT, cont_sig);
+        signal(SIGCONT, cont_handler);
         signal(SIGTSTP, SIG_DFL);
         kill(my_pid, SIGTSTP);
         errno = save_errno;
 }
 
 //----- Come here when we get a signal ---------------------------
-static void catch_sig(int sig)
+static void int_handler(int sig)
 {
-        signal(SIGINT, catch_sig);
+        signal(SIGINT, int_handler);
         siglongjmp(restart, sig);
 }
 #endif /* FEATURE_VI_USE_SIGNALS */
@@ -2934,7 +2931,7 @@ static int file_insert(const char *fn, char *p, int initial)
                 return cnt;
         }
 
-        /* Validate file */
+        // Validate file
         if (fstat(fd, &statbuf) < 0) {
                 status_line_bold_errno(fn);
                 goto fi;
@@ -2960,8 +2957,8 @@ static int file_insert(const char *fn, char *p, int initial)
 #if ENABLE_FEATURE_VI_READONLY
         if (initial
          && ((access(fn, W_OK) < 0) ||
-                /* root will always have access()
-                 * so we check fileperms too */
+                // root will always have access()
+                // so we check fileperms too
                 !(statbuf.st_mode & (S_IWUSR | S_IWGRP | S_IWOTH))
             )
         ) {
@@ -2979,10 +2976,9 @@ static int file_write(char *fn, char *first, char *last)
                 status_line_bold("No current filename");
                 return -2;
         }
-        /* By popular request we do not open file with O_TRUNC,
-         * but instead ftruncate() it _after_ successful write.
-         * Might reduce amount of data lost on power fail etc.
-         */
+        // By popular request we do not open file with O_TRUNC,
+        // but instead ftruncate() it _after_ successful write.
+        // Might reduce amount of data lost on power fail etc.
         fd = open(fn, (O_WRONLY | O_CREAT), 0666);
         if (fd < 0)
                 return -1;
@@ -3036,12 +3032,6 @@ static void go_bottom_and_clear_to_eol(void)
         clear_to_eol();
 }
 
-//----- Erase from cursor to end of screen -----------------------
-static void clear_to_eos(void)
-{
-        write1(ESC_CLEAR2EOS);
-}
-
 //----- Start standout mode ------------------------------------
 static void standout_start(void)
 {
@@ -3068,7 +3058,7 @@ static void indicate_error(void)
 {
 #if ENABLE_FEATURE_VI_CRASHME
         if (crashme > 0)
-                return;                 // generate a random command
+                return;
 #endif
         if (!err_method) {
                 write1(ESC_BELL);
@@ -3177,7 +3167,7 @@ static void print_literal(char *buf, const char *s)
                 }
                 if (c < ' ' || c == 0x7f) {
                         *d++ = '^';
-                        c |= '@'; /* 0x40 */
+                        c |= '@'; // 0x40
                         if (c == 0x7f)
                                 c = '?';
                 }
@@ -3259,17 +3249,17 @@ static int format_edit_status(void)
                 cur, tot, percent);
 
         if (ret >= 0 && ret < trunc_at)
-                return ret;  /* it all fit */
+                return ret;  // it all fit
 
-        return trunc_at;  /* had to truncate */
+        return trunc_at;  // had to truncate
 #undef tot
 }
 
 //----- Force refresh of all Lines -----------------------------
 static void redraw(int full_screen)
 {
-        place_cursor(0, 0);
-        clear_to_eos();
+        // cursor to top,left; clear to the end of screen
+        write1(ESC_SET_CURSOR_TOPLEFT ESC_CLEAR2EOS);
         screen_erase();         // erase the internal screen buffer
         last_status_cksum = 0;  // force status update
         refresh(full_screen);   // this will redraw the entire display
@@ -3354,7 +3344,7 @@ static void refresh(int full_screen)
 #else
                 if (c != columns || r != rows) {
                         full_screen = TRUE;
-                        /* update screen memory since SIGWINCH won't have done it */
+                        // update screen memory since SIGWINCH won't have done it
                         new_screen(rows, columns);
                 }
 #endif
@@ -3431,7 +3421,6 @@ static void refresh(int full_screen)
 
 //---------------------------------------------------------------------
 //----- the Ascii Chart -----------------------------------------------
-//
 //  00 nul   01 soh   02 stx   03 etx   04 eot   05 enq   06 ack   07 bel
 //  08 bs    09 ht    0a nl    0b vt    0c np    0d cr    0e so    0f si
 //  10 dle   11 dc1   12 dc2   13 dc3   14 dc4   15 nak   16 syn   17 etb
@@ -3466,7 +3455,7 @@ static void do_cmd(int c)
 
         show_status_line();
 
-        /* if this is a cursor key, skip these checks */
+        // if this is a cursor key, skip these checks
         switch (c) {
                 case KEYCODE_UP:
                 case KEYCODE_DOWN:
@@ -3499,7 +3488,7 @@ static void do_cmd(int c)
                 }
         }
         if (cmd_mode == 1) {
-                //  hitting "Insert" twice means "R" replace mode
+                // hitting "Insert" twice means "R" replace mode
                 if (c == KEYCODE_INSERT) goto dc5;
                 // insert the char c at "dot"
                 if (1 <= c || Isprint(c)) {
@@ -3958,7 +3947,7 @@ static void do_cmd(int c)
                 }
                 if (cmdcnt == 0)
                         cmdcnt = 1;
-                /* fall through */
+                // fall through
         case 'G':               // G- goto to a line number (default= E-O-F)
                 dot = end - 1;                          // assume E-O-F
                 if (cmdcnt > 0) {