Use has_prefix() instead of strncmp() throughout

This is safer than hardcoded string lengths.

sway/commands/assign.c

@@ -23,7 +23,7 @@ struct cmd_results *cmd_assign(int argc, char **argv) {
 
 	--argc; ++argv;
 
-	if (strncmp(*argv, "→", strlen("→")) == 0) {
+	if (has_prefix(*argv, "→")) {
 		if (argc < 2) {
 			free(criteria);
 			return cmd_results_new(CMD_INVALID, "Missing workspace");

sway/commands/bar/font.c

@@ -11,7 +11,7 @@ struct cmd_results *bar_cmd_font(int argc, char **argv) {
 	char *font = join_args(argv, argc);
 	free(config->current_bar->font);
 
-	if (strncmp(font, "pango:", 6) == 0) {
+	if (has_prefix(font, "pango:")) {
 		if (config->current_bar->pango_markup == PANGO_MARKUP_DEFAULT) {
 			config->current_bar->pango_markup = true;
 		}

sway/commands/bind.c

@@ -367,8 +367,7 @@ static struct cmd_results *cmd_bindsym_or_bindcode(int argc, char **argv,
 			}
 		} else if (strcmp("--exclude-titlebar", argv[0]) == 0) {
 			exclude_titlebar = true;
-		} else if (strncmp("--input-device=", argv[0],
-					strlen("--input-device=")) == 0) {
+		} else if (has_prefix("--input-device=", argv[0])) {
 			free(binding->input);
 			binding->input = strdup(argv[0] + strlen("--input-device="));
 			strip_quotes(binding->input);
@@ -399,7 +398,7 @@ static struct cmd_results *cmd_bindsym_or_bindcode(int argc, char **argv,
 	list_t *split = split_string(argv[0], "+");
 	for (int i = 0; i < split->length; ++i) {
 		// Check for group
-		if (strncmp(split->items[i], "Group", strlen("Group")) == 0) {
+		if (has_prefix(split->items[i], "Group") == 0) {
 			if (binding->group != XKB_LAYOUT_INVALID) {
 				free_sway_binding(binding);
 				list_free_items_and_destroy(split);

sway/commands/font.c

@@ -13,9 +13,9 @@ struct cmd_results *cmd_font(int argc, char **argv) {
 	char *font = join_args(argv, argc);
 	free(config->font);
 
-	if (strncmp(font, "pango:", 6) == 0) {
+	if (has_prefix(font, "pango:")) {
 		config->pango_markup = true;
-		config->font = strdup(font + 6);
+		config->font = strdup(font + strlen("pango:"));
 		free(font);
 	} else {
 		config->pango_markup = false;

sway/commands/gesture.c

@@ -121,8 +121,7 @@ static struct cmd_results *cmd_bind_or_unbind_gesture(int argc, char **argv, boo
 			binding->flags |= BINDING_EXACT;
 		} else if (strcmp("--no-warn", argv[0]) == 0) {
 			warn = false;
-		} else if (strncmp("--input-device=", argv[0],
-					strlen("--input-device=")) == 0) {
+		} else if (has_prefix("--input-device=", argv[0])) {
 			free(binding->input);
 			binding->input = strdup(argv[0] + strlen("--input-device="));
 		} else {

sway/commands/input/events.c

@@ -86,7 +86,7 @@ static void toggle_select_send_events_for_device(struct input_config *ic,
 static void toggle_send_events(int argc, char **argv) {
 	struct input_config *ic = config->handler_context.input_config;
 	bool wildcard = strcmp(ic->identifier, "*") == 0;
-	const char *type = strncmp(ic->identifier, "type:", strlen("type:")) == 0
+	const char *type = has_prefix(ic->identifier, "type:")
 		? ic->identifier + strlen("type:") : NULL;
 	struct sway_input_device *device = NULL;
 	wl_list_for_each(device, &server.input->devices, link) {
@@ -146,8 +146,7 @@ struct cmd_results *input_cmd_events(int argc, char **argv) {
 
 		toggle_send_events(argc - 1, argv + 1);
 
-		if (strcmp(ic->identifier, "*") == 0 ||
-				strncmp(ic->identifier, "type:", strlen("type:")) == 0) {
+		if (strcmp(ic->identifier, "*") == 0 || has_prefix(ic->identifier, "type:")) {
 			// Update the device input configs and then reset the type/wildcard
 			// config send events mode so that is does not override the device
 			// ones. The device ones will be applied when attempting to apply

sway/commands/mark.c

@@ -23,7 +23,7 @@ struct cmd_results *cmd_mark(int argc, char **argv) {
 	}
 
 	bool add = false, toggle = false;
-	while (argc > 0 && strncmp(*argv, "--", 2) == 0) {
+	while (argc > 0 && has_prefix(*argv, "--") == 0) {
 		if (strcmp(*argv, "--add") == 0) {
 			add = true;
 		} else if (strcmp(*argv, "--replace") == 0) {

sway/config.c

@@ -925,8 +925,8 @@ char *do_var_replacement(char *str) {
 		// Find matching variable
 		for (i = 0; i < config->symbols->length; ++i) {
 			struct sway_variable *var = config->symbols->items[i];
-			int vnlen = strlen(var->name);
-			if (strncmp(find, var->name, vnlen) == 0) {
+			if (has_prefix(find, var->name)) {
+				int vnlen = strlen(var->name);
 				int vvlen = strlen(var->value);
 				char *newstr = malloc(strlen(str) - vnlen + vvlen + 1);
 				if (!newstr) {

sway/config/input.c

@@ -300,7 +300,7 @@ struct input_config *store_input_config(struct input_config *ic,
 		return NULL;
 	}
 
-	bool type = strncmp(ic->identifier, "type:", strlen("type:")) == 0;
+	bool type = has_prefix(ic->identifier, "type:");
 	if (type && error && !validate_type_on_existing(ic, error)) {
 		return NULL;
 	}

sway/input/cursor.c

@@ -1212,7 +1212,7 @@ uint32_t get_mouse_bindsym(const char *name, char **error) {
 			SWAY_SCROLL_UP, SWAY_SCROLL_DOWN, SWAY_SCROLL_LEFT,
 			SWAY_SCROLL_RIGHT, BTN_SIDE, BTN_EXTRA};
 		return buttons[number - 1];
-	} else if (strncmp(name, "BTN_", strlen("BTN_")) == 0) {
+	} else if (has_prefix(name, "BTN_")) {
 		// Get event code from name
 		int code = libevdev_event_code_from_name(EV_KEY, name);
 		if (code == -1) {
@@ -1237,7 +1237,7 @@ uint32_t get_mouse_bindcode(const char *name, char **error) {
 		return 0;
 	}
 	const char *event = libevdev_event_code_get_name(EV_KEY, code);
-	if (!event || strncmp(event, "BTN_", strlen("BTN_")) != 0) {
+	if (!event || !has_prefix(event, "BTN_")) {
 		*error = format_str("Event code %d (%s) is not a button",
 			code, event ? event : "(null)");
 		return 0;

sway/input/input-manager.c

@@ -577,7 +577,7 @@ void input_manager_configure_all_input_mappings(void) {
 void input_manager_apply_input_config(struct input_config *input_config) {
 	struct sway_input_device *input_device = NULL;
 	bool wildcard = strcmp(input_config->identifier, "*") == 0;
-	bool type_wildcard = strncmp(input_config->identifier, "type:", 5) == 0;
+	bool type_wildcard = has_prefix(input_config->identifier, "type:");
 	wl_list_for_each(input_device, &server.input->devices, link) {
 		bool type_matches = type_wildcard &&
 			strcmp(input_device_get_type(input_device), input_config->identifier + 5) == 0;

sway/input/libinput.c

@@ -417,13 +417,9 @@ bool sway_libinput_device_is_builtin(struct sway_input_device *sway_device) {
 		return false;
 	}
 
-	const char prefix_platform[] = "platform-";
-	if (strncmp(id_path, prefix_platform, strlen(prefix_platform)) == 0) {
+	if (has_prefix(id_path, "platform-")) {
 		return true;
 	}
 
-	const char prefix_pci[] = "pci-";
-	const char infix_platform[] = "-platform-";
-	return (strncmp(id_path, prefix_pci, strlen(prefix_pci)) == 0) &&
-		strstr(id_path, infix_platform);
+	return has_prefix(id_path, "pci-") && strstr(id_path, "-platform-");
 }

sway/main.c

@@ -159,8 +159,8 @@ void enable_debug_flag(const char *flag) {
 		debug.txn_wait = true;
 	} else if (strcmp(flag, "txn-timings") == 0) {
 		debug.txn_timings = true;
-	} else if (strncmp(flag, "txn-timeout=", 12) == 0) {
-		server.txn_timeout_ms = atoi(&flag[12]);
+	} else if (has_prefix(flag, "txn-timeout=")) {
+		server.txn_timeout_ms = atoi(&flag[strlen("txn-timeout=")]);
 	} else if (strcmp(flag, "legacy-wl-drm") == 0) {
 		debug.legacy_wl_drm = true;
 	} else {

sway/tree/container.c

@@ -696,26 +696,26 @@ size_t parse_title_format(struct sway_container *container, char *buffer) {
 		len += next - format;
 		format = next;
 
-		if (strncmp(next, "%title", 6) == 0) {
+		if (has_prefix(next, "%title")) {
 			if (container->view) {
 				len += append_prop(buffer, view_get_title(container->view));
 			} else {
 				len += container_build_representation(container->pending.layout, container->pending.children, buffer);
 			}
-			format += 6;
+			format += strlen("%title");
 		} else if (container->view) {
-			if (strncmp(next, "%app_id", 7) == 0) {
+			if (has_prefix(next, "%app_id")) {
 				len += append_prop(buffer, view_get_app_id(container->view));
-				format += 7;
-			} else if (strncmp(next, "%class", 6) == 0) {
+				format += strlen("%app_id");
+			} else if (has_prefix(next, "%class")) {
 				len += append_prop(buffer, view_get_class(container->view));
-				format += 6;
-			} else if (strncmp(next, "%instance", 9) == 0) {
+				format += strlen("%class");
+			} else if (has_prefix(next, "%instance")) {
 				len += append_prop(buffer, view_get_instance(container->view));
-				format += 9;
-			} else if (strncmp(next, "%shell", 6) == 0) {
+				format += strlen("%instance");
+			} else if (has_prefix(next, "%shell")) {
 				len += append_prop(buffer, view_get_shell(container->view));
-				format += 6;
+				format += strlen("%shell");
 			} else {
 				lenient_strcat(buffer, "%");
 				++format;
@@ -778,7 +778,7 @@ size_t container_build_representation(enum sway_container_layout layout,
 			len += strlen(identifier);
 			lenient_strcat(buffer, identifier);
 		} else {
-			len += 6;
+			len += strlen("(null)");
 			lenient_strcat(buffer, "(null)");
 		}
 	}

sway/tree/workspace.c

@@ -246,7 +246,7 @@ static void workspace_name_from_binding(const struct sway_binding * binding,
 		}
 
 		// If the command is workspace number <name>, isolate the name
-		if (strncmp(_target, "number ", strlen("number ")) == 0) {
+		if (has_prefix(_target, "number ")) {
 			size_t length = strlen(_target) - strlen("number ") + 1;
 			char *temp = malloc(length);
 			strncpy(temp, _target + strlen("number "), length - 1);

swaybar/ipc.c

@@ -15,6 +15,7 @@
 #include "list.h"
 #include "log.h"
 #include "loop.h"
+#include "stringop.h"
 #include "util.h"
 
 void ipc_send_workspace_command(struct swaybar *bar, const char *ws) {
@@ -45,8 +46,8 @@ void ipc_send_workspace_command(struct swaybar *bar, const char *ws) {
 
 char *parse_font(const char *font) {
 	char *new_font = NULL;
-	if (strncmp("pango:", font, 6) == 0) {
-		font += 6;
+	if (has_prefix("pango:", font)) {
+		font += strlen("pango:");
 	}
 	new_font = strdup(font);
 	return new_font;

swaybar/render.c

@@ -293,11 +293,11 @@ static uint32_t render_status_block(struct render_context *ctx,
 	}
 
 	double offset = 0;
-	if (strncmp(block->align, "left", 4) == 0) {
+	if (has_prefix(block->align, "left")) {
 		offset = x_pos;
-	} else if (strncmp(block->align, "right", 5) == 0) {
+	} else if (has_prefix(block->align, "right")) {
 		offset = x_pos + width - text_width;
-	} else if (strncmp(block->align, "center", 6) == 0) {
+	} else if (has_prefix(block->align, "center")) {
 		offset = x_pos + (width - text_width) / 2;
 	}
 	double text_y = height / 2.0 - text_height / 2.0;

swaybar/tray/item.c

@@ -15,6 +15,7 @@
 #include "cairo_util.h"
 #include "list.h"
 #include "log.h"
+#include "stringop.h"
 #include "wlr-layer-shell-unstable-v1-client-protocol.h"
 
 // TODO menu
@@ -161,7 +162,7 @@ static int get_property_callback(sd_bus_message *msg, void *data,
 	}
 
 	if (strcmp(prop, "Status") == 0 || (sni->status && (sni->status[0] == 'N' ?
-				prop[0] == 'A' : strncmp(prop, "Icon", 4) == 0))) {
+				prop[0] == 'A' : has_prefix(prop, "Icon")))) {
 		set_sni_dirty(sni);
 	}
 cleanup:
@@ -364,7 +365,7 @@ static void handle_click(struct swaybar_sni *sni, int x, int y,
 		method = "ContextMenu";
 	}
 
-	if (strncmp(method, "Scroll", strlen("Scroll")) == 0) {
+	if (has_prefix(method, "Scroll")) {
 		char dir = method[strlen("Scroll")];
 		char *orientation = (dir == 'U' || dir == 'D') ? "vertical" : "horizontal";
 		int sign = (dir == 'U' || dir == 'L') ? -1 : 1;

swaybar/tray/watcher.c

@@ -31,9 +31,9 @@ static int handle_lost_service(sd_bus_message *msg,
 		struct swaybar_watcher *watcher = data;
 		for (int idx = 0; idx < watcher->items->length; ++idx) {
 			char *id = watcher->items->items[idx];
-			int cmp_res = using_standard_protocol(watcher) ?
-				cmp_id(id, service) : strncmp(id, service, strlen(service));
-			if (cmp_res == 0) {
+			bool cmp_res = using_standard_protocol(watcher) ?
+				cmp_id(id, service) == 0 : has_prefix(id, service);
+			if (cmp_res) {
 				sway_log(SWAY_DEBUG, "Unregistering Status Notifier Item '%s'", id);
 				list_del(watcher->items, idx--);
 				sd_bus_emit_signal(watcher->bus, obj_path, watcher->interface,