code-style: various cleanups (#356)

* run_key_handler: make the logic easier to follow
* remove timeout_t
  the typedef is not needed. inline the declaration similar to the other
  static structs.
* simplify estrdup
  reuse emalloc, instead of calling malloc and null-checking.
* win_clear: initialize `e` right away
* process_bindings: explicitly check against NULL
  most pointer checks in the codebase do explicit check.
* use a named constant instead of magic number
  also changes the padding from 3 to 4 bytes according to [0]. but i
  couldn't find any situtation where this mattered, so perhaps the current
  padding is enough. but doesn't hurt adding one more byte.

[0]: https://nullprogram.com/blog/2017/10/06/

Reviewed-on: https://codeberg.org/nsxiv/nsxiv/pulls/356
Reviewed-by: explosion-mental <explosion-mental@noreply.codeberg.org>

main.c

@@ -50,12 +50,6 @@
   (tv)->tv_usec += (t) % 1000 * 1000;   \
 }
 
-typedef struct {
-	struct timeval when;
-	bool active;
-	timeout_f handler;
-} timeout_t;
-
 typedef struct {
 	int err;
 	char *cmd;
@@ -98,12 +92,16 @@ static struct {
 
 bool title_dirty;
 
-static timeout_t timeouts[] = {
-	{ { 0, 0 }, false, redraw       },
-	{ { 0, 0 }, false, reset_cursor },
-	{ { 0, 0 }, false, slideshow    },
-	{ { 0, 0 }, false, animate      },
-	{ { 0, 0 }, false, clear_resize },
+static struct {
+	timeout_f handler;
+	struct timeval when;
+	bool active;
+} timeouts[] = {
+	{ redraw       },
+	{ reset_cursor },
+	{ slideshow    },
+	{ animate      },
+	{ clear_resize },
 };
 
 /**************************
@@ -611,14 +609,12 @@ static bool run_key_handler(const char *key, unsigned int mask)
 	/* drop user input events that occurred while running the key handler */
 	while (XCheckIfEvent(win.env.dpy, &dump, is_input_ev, NULL));
 
-	if (mode == MODE_IMAGE) {
-		if (changed) {
-			img_close(&img, true);
-			load_image(fileidx);
-		}
-	}
-	if (mode == MODE_THUMB || !changed)
+	if (mode == MODE_IMAGE && changed) {
+		img_close(&img, true);
+		load_image(fileidx);
+	} else {
 		open_info();
+	}
 	free(oldst);
 	reset_cursor();
 	return true;
@@ -633,7 +629,7 @@ static bool process_bindings(const keymap_t *bindings, unsigned int len, KeySym
 	for (i = 0; i < len; i++) {
 		if (bindings[i].ksym_or_button == ksym_or_button &&
 		    MODMASK(bindings[i].mask | implicit_mod) == MODMASK(state) &&
-		    bindings[i].cmd.func &&
+		    bindings[i].cmd.func != NULL &&
 		    (bindings[i].cmd.mode == MODE_ALL || bindings[i].cmd.mode == mode))
 		{
 			if (bindings[i].cmd.func(bindings[i].arg))

util.c

@@ -60,14 +60,8 @@ void* erealloc(void *ptr, size_t size)
 
 char* estrdup(const char *s)
 {
-	char *d;
 	size_t n = strlen(s) + 1;
-
-	d = malloc(n);
-	if (d == NULL)
-		error(EXIT_FAILURE, errno, NULL);
-	memcpy(d, s, n);
-	return d;
+	return memcpy(emalloc(n), s, n);
 }
 
 void error(int eval, int err, const char* fmt, ...)

window.c

@@ -33,6 +33,7 @@
 
 #if HAVE_LIBFONTS
 #include "utf8.h"
+#define UTF8_PADDING 4  /* utf8_decode requires 4 bytes of zero padding */
 static XftFont *font;
 static double fontsize;
 #define TEXTWIDTH(win, text, len) \
@@ -112,7 +113,7 @@ void win_init(win_t *win)
 #if HAVE_LIBFONTS
 	const char *bar_fg, *bar_bg, *f;
 
-	static char lbuf[512 + 3], rbuf[64 + 3];
+	static char lbuf[512 + UTF8_PADDING], rbuf[64 + UTF8_PADDING];
 #endif
 
 	memset(win, 0, sizeof(win_t));
@@ -153,9 +154,8 @@ void win_init(win_t *win)
 
 	win->bar.l.buf = lbuf;
 	win->bar.r.buf = rbuf;
-	/* 3 padding bytes needed by utf8_decode */
-	win->bar.l.size = sizeof(lbuf) - 3;
-	win->bar.r.size = sizeof(rbuf) - 3;
+	win->bar.l.size = sizeof(lbuf) - UTF8_PADDING;
+	win->bar.r.size = sizeof(rbuf) - UTF8_PADDING;
 	win->bar.h = options->hide_bar ? 0 : barheight;
 	win->bar.top = TOP_STATUSBAR;
 #endif /* HAVE_LIBFONTS */
@@ -388,9 +388,7 @@ void win_toggle_bar(win_t *win)
 
 void win_clear(win_t *win)
 {
-	win_env_t *e;
-
-	e = &win->env;
+	win_env_t *e = &win->env;
 
 	if (win->w > win->buf.w || win->h + win->bar.h > win->buf.h) {
 		XFreePixmap(e->dpy, win->buf.pm);