vcurses: add return value assertions using a semantic patch

The only relevant change in this patch is the curses.cocci file. All other
changes are just the result of applying that patch, with additional manual
polishing where coccinelle caused unwanted cstyle changes.

We explicitly ignore the return value of some curses functions through the IC()
macro:

* curs_set is known to be ok to fail for terminals which do have no capability
  to make the cursor invisible and

* all print-related functions, which have the unpleasent bug to return ERR when
  the cursor ends up outside the screen/window _after_ completing the print
  function.

For most other curses functions, we add AC() to check that they do not return
ERR.

bin/varnishhist/varnishhist.c

@@ -150,13 +150,13 @@ update(void)
 		(void)mvaddch(LINES - 2, k, '-');
 	for (i = 0, j = hist_low; i < hist_range; ++i, ++j) {
 		(void)mvaddch(LINES - 2, w * i, '+');
-		mvprintw(LINES - 1, w * i, "|1e%d", j);
+		IC(mvprintw(LINES - 1, w * i, "|1e%d", j));
 	}
 
 	if (end_of_file)
-		mvprintw(0, 0, "%*s", COLS - 1, "EOF");
+		IC(mvprintw(0, 0, "%*s", COLS - 1, "EOF"));
 	else
-		mvprintw(0, 0, "%*s", COLS - 1, ident);
+		IC(mvprintw(0, 0, "%*s", COLS - 1, ident));
 
 	/* count our flock */
 	memset(bm, 0, sizeof bm);
@@ -178,14 +178,15 @@ update(void)
 	if (vsl_t0 > 0) {
 		VTIM_format(vsl_ts, t);
 
-		mvprintw(0, 0, "1:%u, n = %u, d = %g @ %s x %g",
-		    scale, nhist, 1e-3 * ms_delay, t, timebend);
-	} else
-		mvprintw(0, 0, "1:%u, n = %u, d = %g",
-		    scale, nhist, 1e-3 * ms_delay);
+		IC(mvprintw(0, 0, "1:%u, n = %u, d = %g @ %s x %g",
+		    scale, nhist, 1e-3 * ms_delay, t, timebend));
+	} else {
+		IC(mvprintw(0, 0, "1:%u, n = %u, d = %g",
+		    scale, nhist, 1e-3 * ms_delay));
+	}
 
 	for (j = 5; j < LINES - 2; j += 5)
-		mvprintw((LINES - 2) - j, 0, "%u_", j * scale);
+		IC(mvprintw((LINES - 2) - j, 0, "%u_", j * scale));
 
 	/* show them */
 	for (k = 0; k < n; ++k) {
@@ -396,7 +397,7 @@ do_curses(void *arg)
 #endif
 		case '\014':	/* Ctrl-L */
 		case '\024':	/* Ctrl-T */
-			redrawwin(stdscr);
+			AC(redrawwin(stdscr));
 			AC(refresh());
 			break;
 		case '\032':	/* Ctrl-Z */

bin/varnishtop/varnishtop.c

@@ -257,7 +257,7 @@ do_curses(void *arg)
 	AC(noecho());
 	AC(nonl());
 	AC(intrflush(stdscr, FALSE));
-	(void)curs_set(0);
+	IC(curs_set(0));
 	AC(erase());
 	timeout(1000);
 	while (!VSIG_int && !VSIG_term && !VSIG_hup) {

tools/coccinelle/curses.cocci

+
+// XXX can we reuse the pattern somehow without inheriting the metavariable?
+
+@@
+identifier curs =~ "^(curs_set|(w|mv|mvw|vw_)?printw)$";
+expression list EL;
+@@
+-curs(EL);
++IC(curs(EL));
+
+@@
+identifier curs =~ "^(curs_set|(w|mv|mvw|vw_)?printw)$";
+expression list EL;
+@@
+-(void)curs(EL);
++IC(curs(EL));
+
+// ensure we undo AC() patching when we move patterns to IC()
+@@
+identifier curs =~ "^(curs_set|(w|mv|mvw|vw_)?printw)$";
+expression list EL;
+@@
+-AC(curs(EL));
++IC(curs(EL));
+
+@@
+identifier curs =~ "^(endwin|(no)?cbreak|(no)?echo|intrflush|keypad|meta|nodelay|notimeout|(no)?nl|(no)?raw|w?erase|w?clear|w?clrtobot|w?clrtoeol|(w|wnout)?refresh|doupdate|redrawwin|wredrawln|beep|flash|delwin|mv(der)?win|syncok)$";
+expression list EL;
+@@
+-curs(EL);
++AC(curs(EL));
+
+@@
+identifier curs =~ "^(endwin|(no)?cbreak|(no)?echo|intrflush|keypad|meta|nodelay|notimeout|(no)?nl|(no)?raw|w?erase|w?clear|w?clrtobot|w?clrtoeol|(w|wnout)?refresh|doupdate|redrawwin|wredrawln|beep|flash|delwin|mv(der)?win|syncok)$";
+expression list EL;
+@@
+-(void)curs(EL);
++AC(curs(EL));
+
+@@
+identifier curs =~ "^(endwin|(no)?cbreak|(no)?echo|intrflush|keypad|meta|nodelay|notimeout|(no)?nl|(no)?raw|w?erase|w?clear|w?clrtobot|w?clrtoeol|(w|wnout)?refresh|doupdate|redrawwin|wredrawln|beep|flash|delwin|mv(der)?win|syncok)$";
+expression list EL;
+@@
+-assert(curs(EL) != ERR);
++AC(curs(EL));