Implement quit count safeguard.

2 files changed, 37 insertions, 3 deletions

diff --git a/pw.1 b/pw.1
index 15f3d2f..5a580db 100644
--- a/pw.1
+++ b/pw.1
@@ -148,7 +148,10 @@ command.
 The commands are:
 
 .IP "\fBq\fP, \fBCtrl-C\fP"
-Quit the program.
+Quit the program. Must be used multiple times in succession if a quit
+count greater than 1 is in effect. (See the
+.B -q
+option).
 
 .IP "\fBl\fP, \fILeft Arrow\fP"
 Scroll the display to the left.
@@ -571,6 +574,18 @@ and staying in the interactive mode. This is useful when the last portion
 of the input is of interest, and contains long lines that require
 horizontal scrolling.
 
+.IP "\fB-q\fP \fIinteger\fP"
+Install a quit count specified by
+.I integer
+which must be positive. The quit count determines how many times the
+.B q
+or
+.B Ctrl-C
+commands have to be issued in succession before
+.I pw
+will quit. This is a safeguard against quitting accidentally. The default
+is 1: the commands quit immediately.
+
 .IP \fB-E\fP
 Enable extended regular expressions (EREs). By default, regular expressions
 processed by
diff --git a/pw.c b/pw.c
index 01dfd68..1c883ec 100644
--- a/pw.c
+++ b/pw.c
@@ -243,6 +243,7 @@ static void usage(void)
           "-l realnum      long update interval (s)\n"
           "-n integer      display size (# of lines)\n"
           "-d              do not quit on end-of-input\n"
+          "-q integer      Require this many repetitions of q to quit\n"
           "-E              treat regular expressions as extended\n"
           "-B              treat regular expressions as basic (default)\n\n"
           "-g [!]pattern   add pattern to grep stack; ! inverts.\n\n"
@@ -702,6 +703,7 @@ int main(int argc, char **argv)
     kbd_colon, kbd_result, kbd_trig
   };
   int auto_quit = 1;
+  int quit_count = 1, quit_countdown = quit_count;
   int exit_status = EXIT_FAILURE;
   char cmdbuf[cmdsize], *curcmd = 0, *savedcmd = 0;
 #ifdef SIGWINCH
@@ -726,7 +728,7 @@ int main(int argc, char **argv)
     }
   }
 
-  while ((opt = getopt(argc, argv, "n:i:l:dEBg:")) != -1) {
+  while ((opt = getopt(argc, argv, "n:i:l:dEBg:q:")) != -1) {
     switch (opt) {
     case 'n':
       {
@@ -756,6 +758,15 @@ int main(int argc, char **argv)
     case 'd':
       auto_quit = 0;
       break;
+    case 'q':
+      {
+        char *err;
+        if ((quit_countdown = quit_count = getzp(optarg, &err)) < 0) {
+          error("-%c option: %s\n", opt, err);
+          return EXIT_FAILURE;
+        }
+        break;
+      }
     case 'E':
       regex_flags = REG_EXTENDED;
       break;
@@ -1044,9 +1055,17 @@ int main(int argc, char **argv)
           curcmd = 0;
           // fallthrough
         case kbd_cmd:
+          if (ch != 'q' && ch != 3)
+            quit_countdown = quit_count;
           switch (ch) {
           case 'q': case 3:
-            kbd_state = kbd_exit;
+            if (--quit_countdown == 0) {
+              kbd_state = kbd_exit;
+            } else {
+              sprintf(cmdbuf, "%d more to quit", quit_countdown);
+              curcmd = cmdbuf;
+              kbd_state = kbd_result;
+            }
             break;
           case 'h':
             if (hpos >= 8) {