Mouseclicks are no longer delayed (#353)

This patch changes the mouseinterval to 0. And handles detection of
doubleclicking events internally.

This allows much faster response times for mouse clicks as nnn no longer
has to wait for ncurses to confirm what type of click it was.

It introduces a new config setting for changing how many milliseconds it
may take for a double click to be registered.

src/nnn.c

@@ -107,6 +107,7 @@
 #define S_BLKSIZE 512 /* S_BLKSIZE is missing on Android NDK (Termux) */
 #endif
 
+#define _ABSSUB(N, M) (((N) <= (M)) ? ((M) - (N)) : ((N) - (M)))
 #define LEN(x) (sizeof(x) / sizeof(*(x)))
 #undef MIN
 #define MIN(x, y) ((x) < (y) ? (x) : (y))
@@ -1015,12 +1016,12 @@ static bool initcurses(mmask_t *oldmask)
 	//intrflush(stdscr, FALSE);
 	keypad(stdscr, TRUE);
 #if NCURSES_MOUSE_VERSION <= 1
-	mousemask(BUTTON1_CLICKED | BUTTON1_DOUBLE_CLICKED, oldmask);
+	mousemask(BUTTON1_PRESSED | BUTTON1_DOUBLE_CLICKED, oldmask);
 #else
-	mousemask(BUTTON1_CLICKED | BUTTON1_DOUBLE_CLICKED | BUTTON4_PRESSED | BUTTON5_PRESSED,
+	mousemask(BUTTON1_PRESSED | BUTTON4_PRESSED | BUTTON5_PRESSED,
 		  oldmask);
 #endif
-	mouseinterval(400);
+	mouseinterval(0);
 	curs_set(FALSE); /* Hide cursor */
 	start_color();
 	use_default_colors();
@@ -3542,6 +3543,8 @@ static void browse(char *ipath)
 	struct stat sb;
 	char *path, *lastdir, *lastname, *dir, *tmp;
 	MEVENT event;
+	struct timespec mousetimings[2] = {{.tv_sec = 0, .tv_nsec = 0}, {.tv_sec = 0, .tv_nsec = 0}};
+	bool currentmouse = 1;
 
 	atexit(dentfree);
 
@@ -3663,7 +3666,7 @@ nochange:
 				goto nochange; // fallthrough
 		case SEL_BACK:
 			/* Handle clicking on a context at the top */
-			if (sel == SEL_CLICK && event.bstate == BUTTON1_CLICKED && event.y == 0) {
+			if (sel == SEL_CLICK && event.bstate == BUTTON1_PRESSED && event.y == 0) {
 				/* Get context from: "[1 2 3 4]..." */
 				r = event.x >> 1;
 
@@ -3715,7 +3718,7 @@ nochange:
 #endif
 
 			/* Toggle filter mode on left click on last 2 lines */
-			if (event.y >= xlines - 2) {
+			if (event.y >= xlines - 2 && event.bstate == BUTTON1_PRESSED) {
 				cfg.filtermode ^= 1;
 				if (cfg.filtermode) {
 					presel = FILTER;
@@ -3731,13 +3734,18 @@ nochange:
 			}
 
 			/* Handle clicking on a file */
-			if (2 <= event.y && event.y <= ndents + 1) {
+			if (2 <= event.y && event.y <= ndents + 1 && event.bstate == BUTTON1_PRESSED) {
 				r = curscroll + (event.y - 2);
 				move_cursor(r, 1);
+				currentmouse ^= 1;
+				clock_gettime(CLOCK_MONOTONIC_RAW, &mousetimings[currentmouse]);
 
 				/*Single click just selects, double click also opens */
-				if (event.bstate != BUTTON1_DOUBLE_CLICKED)
+				if (((_ABSSUB(mousetimings[0].tv_sec, mousetimings[1].tv_sec) << 30)
+				  + (mousetimings[0].tv_nsec - mousetimings[1].tv_nsec))
+					> 400000000)
 					break;
+				mousetimings[currentmouse].tv_sec = 0;
 			} else {
 				if (cfg.filtermode)
 					presel = FILTER;