config/input: validate xkb keymap before storing

This allows for an optional validation stage when storing an input
config. Currently, only the xkb keymap is validated. If storing the
delta input config will result in any invalid xkb keymaps, the input
config will not be stored and error will be populated with the first
line of the xkbcommon log.

1 files changed, 105 insertions, 29 deletions

diff --git a/sway/config/input.c b/sway/config/input.c
index 9c533e71..c4f64eb8 100644
--- a/sway/config/input.c
+++ b/sway/config/input.c
@@ -3,6 +3,7 @@
 #include <limits.h>
 #include <float.h>
 #include "sway/config.h"
+#include "sway/input/keyboard.h"
 #include "log.h"
 
 struct input_config *new_input_config(const char* identifier) {
@@ -133,22 +134,82 @@ void merge_input_config(struct input_config *dst, struct input_config *src) {
 	}
 }
 
-static void merge_wildcard_on_all(struct input_config *wildcard) {
+static bool validate_xkb_merge(struct input_config *dest,
+		struct input_config *src, char **xkb_error) {
+	struct input_config *temp = new_input_config("temp");
+	if (dest) {
+		merge_input_config(temp, dest);
+	}
+	merge_input_config(temp, src);
+
+	struct xkb_keymap *keymap = sway_keyboard_compile_keymap(temp, xkb_error);
+	free_input_config(temp);
+	if (!keymap) {
+		return false;
+	}
+
+	xkb_keymap_unref(keymap);
+	return true;
+}
+
+static bool validate_wildcard_on_all(struct input_config *wildcard,
+		char **error) {
 	for (int i = 0; i < config->input_configs->length; i++) {
 		struct input_config *ic = config->input_configs->items[i];
 		if (strcmp(wildcard->identifier, ic->identifier) != 0) {
-			sway_log(SWAY_DEBUG, "Merging input * config on %s", ic->identifier);
-			merge_input_config(ic, wildcard);
+			sway_log(SWAY_DEBUG, "Validating xkb merge of * on %s",
+					ic->identifier);
+			if (!validate_xkb_merge(ic, wildcard, error)) {
+				return false;
+			}
 		}
 	}
 
 	for (int i = 0; i < config->input_type_configs->length; i++) {
 		struct input_config *ic = config->input_type_configs->items[i];
+		sway_log(SWAY_DEBUG, "Validating xkb merge of * config on %s",
+				ic->identifier);
+		if (!validate_xkb_merge(ic, wildcard, error)) {
+			return false;
+		}
+	}
+
+	return true;
+}
+
+static void merge_wildcard_on_all(struct input_config *wildcard) {
+	for (int i = 0; i < config->input_configs->length; i++) {
+		struct input_config *ic = config->input_configs->items[i];
 		if (strcmp(wildcard->identifier, ic->identifier) != 0) {
 			sway_log(SWAY_DEBUG, "Merging input * config on %s", ic->identifier);
 			merge_input_config(ic, wildcard);
 		}
 	}
+
+	for (int i = 0; i < config->input_type_configs->length; i++) {
+		struct input_config *ic = config->input_type_configs->items[i];
+		sway_log(SWAY_DEBUG, "Merging input * config on %s", ic->identifier);
+		merge_input_config(ic, wildcard);
+	}
+}
+
+static bool validate_type_on_existing(struct input_config *type_wildcard,
+		char **error) {
+	for (int i = 0; i < config->input_configs->length; i++) {
+		struct input_config *ic = config->input_configs->items[i];
+		if (ic->input_type == NULL) {
+			continue;
+		}
+
+		if (strcmp(ic->input_type, type_wildcard->identifier + 5) == 0) {
+			sway_log(SWAY_DEBUG, "Validating merge of %s on %s",
+				type_wildcard->identifier, ic->identifier);
+			if (!validate_xkb_merge(ic, type_wildcard, error)) {
+				return false;
+			}
+		}
+	}
+	return true;
 }
 
 static void merge_type_on_existing(struct input_config *type_wildcard) {
@@ -167,44 +228,59 @@ static void merge_type_on_existing(struct input_config *type_wildcard) {
 	}
 }
 
-struct input_config *store_input_config(struct input_config *ic) {
+struct input_config *store_input_config(struct input_config *ic,
+		char **error) {
 	bool wildcard = strcmp(ic->identifier, "*") == 0;
+	if (wildcard && error && !validate_wildcard_on_all(ic, error)) {
+		return NULL;
+	}
+
+	bool type = strncmp(ic->identifier, "type:", strlen("type:")) == 0;
+	if (type && error && !validate_type_on_existing(ic, error)) {
+		return NULL;
+	}
+
+	list_t *config_list = type ? config->input_type_configs
+		: config->input_configs;
+
+	struct input_config *current = NULL;
+	bool new_current = false;
+
+	int i = list_seq_find(config_list, input_identifier_cmp, ic->identifier);
+	if (i >= 0) {
+		current = config_list->items[i];
+	}
+
+	i = list_seq_find(config->input_configs, input_identifier_cmp, "*");
+	if (!current && i >= 0) {
+		current = new_input_config(ic->identifier);
+		merge_input_config(current, config->input_configs->items[i]);
+		new_current = true;
+	}
+
+	if (error && !validate_xkb_merge(current, ic, error)) {
+		if (new_current) {
+			free_input_config(current);
+		}
+		return NULL;
+	}
+
 	if (wildcard) {
 		merge_wildcard_on_all(ic);
 	}
 
-	list_t *config_list = NULL;
-	if (strncmp(ic->identifier, "type:", 5) == 0) {
-		config_list = config->input_type_configs;
+	if (type) {
 		merge_type_on_existing(ic);
-	} else {
-		config_list = config->input_configs;
 	}
 
-	int i = list_seq_find(config_list, input_identifier_cmp,
-			ic->identifier);
-	if (i >= 0) {
-		sway_log(SWAY_DEBUG, "Merging on top of existing input config");
-		struct input_config *current = config_list->items[i];
+	if (current) {
 		merge_input_config(current, ic);
 		free_input_config(ic);
 		ic = current;
-	} else if (!wildcard) {
-		sway_log(SWAY_DEBUG, "Adding non-wildcard input config");
-		i = list_seq_find(config->input_configs, input_identifier_cmp, "*");
-		if (i >= 0) {
-			sway_log(SWAY_DEBUG, "Merging on top of input * config");
-			struct input_config *current = new_input_config(ic->identifier);
-			merge_input_config(current, config->input_configs->items[i]);
-			merge_input_config(current, ic);
-			free_input_config(ic);
-			ic = current;
-		}
+	}
+
+	if (!current || new_current) {
 		list_add(config_list, ic);
-	} else {
-		// New wildcard config. Just add it
-		sway_log(SWAY_DEBUG, "Adding input * config");
-		list_add(config->input_configs, ic);
 	}
 
 	sway_log(SWAY_DEBUG, "Config stored for input %s", ic->identifier);