Add ARRAY_SIZE() macro

include/common/array-size.h

@@ -0,0 +1,19 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef LABWC_ARRAY_SIZE_H
+#define LABWC_ARRAY_SIZE_H
+
+/**
+ * ARRAY_SIZE() - Get the number of elements in array.
+ * @arr: array to be sized
+ *
+ * This does not work on pointers.
+ *
+ * Recent versions of GCC and clang support -Werror=sizeof-pointer-div
+ * and thus avoids using constructs such as:
+ *
+ * #define same_type(a, b) (__builtin_types_compatible_p(typeof(a), typeof(b)) == 1)
+ * #define ARRAY_SIZE(a) ({ static_assert(!same_type(a, &(a)[0])); sizeof(a) / sizeof(a[0]); })
+ */
+#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]))
+
+#endif /* LABWC_ARRAY_SIZE_H */

include/ssd-internal.h

@@ -3,13 +3,14 @@
 #define LABWC_SSD_INTERNAL_H
 
 #include <wlr/util/box.h>
+#include "common/array-size.h"
 #include "ssd.h"
 
 #define FOR_EACH(tmp, ...) \
 { \
 	__typeof__(tmp) _x[] = { __VA_ARGS__, NULL }; \
 	size_t _i = 0; \
-	for ((tmp) = _x[_i]; _i < sizeof(_x) / sizeof(_x[0]) - 1; (tmp) = _x[++_i])
+	for ((tmp) = _x[_i]; _i < ARRAY_SIZE(_x) - 1; (tmp) = _x[++_i])
 
 #define FOR_EACH_END }
 

scripts/checkpatch.pl

@@ -62,7 +62,6 @@ my @ignore = (
 	"OPEN_ENDED_LINE",
 	"MACRO_ARG_REUSE",
 	"PREFER_FALLTHROUGH",
-	"ARRAY_SIZE",
 	"INITIALISED_STATIC",
 	"UNNECESSARY_ELSE",
 );

src/cursor.c

@@ -7,6 +7,7 @@
 #include <wlr/types/wlr_primary_selection.h>
 #include <wlr/util/region.h>
 #include "action.h"
+#include "common/array-size.h"
 #include "common/mem.h"
 #include "common/scene-helpers.h"
 #include "config/mousebind.h"
@@ -51,14 +52,12 @@ static const char * const cursors_x11[] = {
 	"left_side"
 };
 
-#define ARRAY_SIZE(array) (sizeof(array) / sizeof((array)[0]))
 static_assert(
 	ARRAY_SIZE(cursors_xdg) == LAB_CURSOR_COUNT,
 	"XDG cursor names are out of sync");
 static_assert(
 	ARRAY_SIZE(cursors_x11) == LAB_CURSOR_COUNT,
 	"X11 cursor names are out of sync");
-#undef ARRAY_SIZE
 
 enum lab_cursors
 cursor_get_from_edge(uint32_t resize_edges)

src/layers.c

@@ -14,6 +14,7 @@
 #include <wayland-server.h>
 #include <wlr/types/wlr_layer_shell_v1.h>
 #include <wlr/util/log.h>
+#include "common/array-size.h"
 #include "common/list.h"
 #include "common/mem.h"
 #include "config/rcxml.h"
@@ -76,8 +77,7 @@ layers_arrange(struct output *output)
 		return;
 	}
 
-	int nr_layers = sizeof(output->layer_tree) / sizeof(output->layer_tree[0]);
-	for (int i = 0; i < nr_layers; i++) {
+	for (size_t i = 0; i < ARRAY_SIZE(output->layer_tree); i++) {
 		struct wlr_scene_tree *layer = output->layer_tree[i];
 
 		/*

src/output.c

@@ -16,6 +16,7 @@
 #include <wlr/types/wlr_scene.h>
 #include <wlr/util/region.h>
 #include <wlr/util/log.h>
+#include "common/array-size.h"
 #include "common/mem.h"
 #include "labwc.h"
 #include "layers.h"
@@ -48,8 +49,7 @@ output_destroy_notify(struct wl_listener *listener, void *data)
 	wl_list_remove(&output->frame.link);
 	wl_list_remove(&output->destroy.link);
 
-	int nr_layers = sizeof(output->layer_tree) / sizeof(output->layer_tree[0]);
-	for (int i = 0; i < nr_layers; i++) {
+	for (size_t i = 0; i < ARRAY_SIZE(output->layer_tree); i++) {
 		wlr_scene_node_destroy(&output->layer_tree[i]->node);
 	}
 	wlr_scene_node_destroy(&output->layer_popup_tree->node);
@@ -186,8 +186,7 @@ new_output_notify(struct wl_listener *listener, void *data)
 	 * Create layer-trees (background, bottom, top and overlay) and
 	 * a layer-popup-tree.
 	 */
-	int nr_layers = sizeof(output->layer_tree) / sizeof(output->layer_tree[0]);
-	for (int i = 0; i < nr_layers; i++) {
+	for (size_t i = 0; i < ARRAY_SIZE(output->layer_tree); i++) {
 		output->layer_tree[i] =
 			wlr_scene_tree_create(&server->scene->tree);
 		node_descriptor_create(&output->layer_tree[i]->node,

src/ssd/ssd_titlebar.c

@@ -105,7 +105,7 @@ set_squared_corners(struct ssd *ssd, bool enable)
 	enum ssd_part_type ssd_type[2] = { LAB_SSD_BUTTON_WINDOW_MENU, LAB_SSD_BUTTON_CLOSE };
 
 	FOR_EACH_STATE(ssd, subtree) {
-		for (size_t i = 0; i < sizeof(ssd_type) / sizeof(ssd_type[0]); i++) {
+		for (size_t i = 0; i < ARRAY_SIZE(ssd_type); i++) {
 			part = ssd_get_part(&subtree->parts, ssd_type[i]);
 			struct ssd_button *button = node_ssd_button_from_node(part->node);
 

src/theme.c

@@ -19,6 +19,7 @@
 #include <wlr/util/box.h>
 #include <wlr/util/log.h>
 #include <strings.h>
+#include "common/array-size.h"
 #include "common/dir.h"
 #include "common/font.h"
 #include "common/graphic-helpers.h"
@@ -109,7 +110,7 @@ load_buttons(struct theme *theme)
 	};
 
 	char filename[4096] = {0};
-	for (size_t i = 0; i < sizeof(buttons) / sizeof(buttons[0]); ++i) {
+	for (size_t i = 0; i < ARRAY_SIZE(buttons); ++i) {
 		struct button *b = &buttons[i];
 
 		drop(b->active.buffer);