config/output: revamp identifier/name layering

This revamps the way that output configs are handled when referencing
an output by both identifier and name. If an output is always referred
to by name or by identifier, this should have no noticeable change. As
soon as there is a name output config and an identifier output config
that matches an output, an output config is generated that is named
`<identifier> on <name>` that is generated with the identifier output
config merged on top of the name output config and stored. When a
change to either is stored, the delta is merged on top of that
"id on name" output config, as well. If the "id on name" output config
exists, it has the highest precedence and will be used when applying
a config to the output.

This fixes the following case:
- `swaymsg output <name> bg /path/to/wallpaper1 fill`
- `swaymsg output <identifier> bg /path/to/wallpaper2 fill`
- `swaymsg output <name> dpms on`

Without this, the wallpaper is changed to `/path/to/wallpaper1`. With
this, the wallpaper remains `/path/to/wallpaper2`.

sway/config/output.c

@@ -98,10 +98,67 @@ static void merge_wildcard_on_all(struct output_config *wildcard) {
 	}
 }
 
+static void merge_id_on_name(struct output_config *oc) {
+	char *id_on_name = NULL;
+	char id[128];
+	char *name = NULL;
+	struct sway_output *output;
+	wl_list_for_each(output, &root->all_outputs, link) {
+		name = output->wlr_output->name;
+		output_get_identifier(id, sizeof(id), output);
+		if (strcmp(name, oc->name) != 0 || strcmp(id, oc->name) != 0) {
+			size_t length = snprintf(NULL, 0, "%s on %s", id, name) + 1;
+			id_on_name = malloc(length);
+			if (!id_on_name) {
+				sway_log(SWAY_ERROR, "Failed to allocate id on name string");
+				return;
+			}
+			snprintf(id_on_name, length, "%s on %s", id, name);
+			break;
+		}
+	}
+
+	if (!id_on_name) {
+		return;
+	}
+
+	int i = list_seq_find(config->output_configs, output_name_cmp, id_on_name);
+	if (i >= 0) {
+		sway_log(SWAY_DEBUG, "Merging on top of existing id on name config");
+		merge_output_config(config->output_configs->items[i], oc);
+	} else {
+		// If both a name and identifier config, exist generate an id on name
+		int ni = list_seq_find(config->output_configs, output_name_cmp, name);
+		int ii = list_seq_find(config->output_configs, output_name_cmp, id);
+		if ((ni >= 0 && ii >= 0) || (ni >= 0 && strcmp(oc->name, id) == 0)
+				|| (ii >= 0 && strcmp(oc->name, name) == 0)) {
+			struct output_config *ion_oc = new_output_config(id_on_name);
+			if (ni >= 0) {
+				merge_output_config(ion_oc, config->output_configs->items[ni]);
+			}
+			if (ii >= 0) {
+				merge_output_config(ion_oc, config->output_configs->items[ii]);
+			}
+			merge_output_config(ion_oc, oc);
+			list_add(config->output_configs, ion_oc);
+			sway_log(SWAY_DEBUG, "Generated id on name output config \"%s\""
+				" (enabled: %d) (%dx%d@%fHz position %d,%d scale %f "
+				"transform %d) (bg %s %s) (dpms %d)", ion_oc->name,
+				ion_oc->enabled, ion_oc->width, ion_oc->height,
+				ion_oc->refresh_rate, ion_oc->x, ion_oc->y, ion_oc->scale,
+				ion_oc->transform, ion_oc->background,
+				ion_oc->background_option, ion_oc->dpms_state);
+		}
+	}
+	free(id_on_name);
+}
+
 struct output_config *store_output_config(struct output_config *oc) {
 	bool wildcard = strcmp(oc->name, "*") == 0;
 	if (wildcard) {
 		merge_wildcard_on_all(oc);
+	} else {
+		merge_id_on_name(oc);
 	}
 
 	int i = list_seq_find(config->output_configs, output_name_cmp, oc->name);
@@ -374,35 +431,51 @@ static void default_output_config(struct output_config *oc,
 static struct output_config *get_output_config(char *identifier,
 		struct sway_output *sway_output) {
 	const char *name = sway_output->wlr_output->name;
+
+	struct output_config *oc_id_on_name = NULL;
 	struct output_config *oc_name = NULL;
-	int i = list_seq_find(config->output_configs, output_name_cmp, name);
+	struct output_config *oc_id = NULL;
+
+	size_t length = snprintf(NULL, 0, "%s on %s", identifier, name) + 1;
+	char *id_on_name = malloc(length);
+	snprintf(id_on_name, length, "%s on %s", identifier, name);
+	int i = list_seq_find(config->output_configs, output_name_cmp, id_on_name);
+	if (i >= 0) {
+		oc_id_on_name = config->output_configs->items[i];
+	} else {
+		i = list_seq_find(config->output_configs, output_name_cmp, name);
 		if (i >= 0) {
 			oc_name = config->output_configs->items[i];
 		}
 
-	struct output_config *oc_id = NULL;
 		i = list_seq_find(config->output_configs, output_name_cmp, identifier);
 		if (i >= 0) {
 			oc_id = config->output_configs->items[i];
 		}
+	}
 
 	struct output_config *result = new_output_config("temp");
 	if (config->reloading) {
 		default_output_config(result, sway_output->wlr_output);
 	}
-	if (oc_name && oc_id) {
+	if (oc_id_on_name) {
+		// Already have an identifier on name config, use that
+		free(result->name);
+		result->name = strdup(id_on_name);
+		merge_output_config(result, oc_id_on_name);
+	} else if (oc_name && oc_id) {
 		// Generate a config named `<identifier> on <name>` which contains a
 		// merged copy of the identifier on name. This will make sure that both
 		// identifier and name configs are respected, with identifier getting
 		// priority
-		size_t length = snprintf(NULL, 0, "%s on %s", identifier, name) + 1;
+		struct output_config *temp = new_output_config(id_on_name);
-		char *temp = malloc(length);
+		merge_output_config(temp, oc_name);
-		snprintf(temp, length, "%s on %s", identifier, name);
+		merge_output_config(temp, oc_id);
+		list_add(config->output_configs, temp);
 
 		free(result->name);
-		result->name = temp;
+		result->name = strdup(id_on_name);
-		merge_output_config(result, oc_name);
+		merge_output_config(result, temp);
-		merge_output_config(result, oc_id);
 
 		sway_log(SWAY_DEBUG, "Generated output config \"%s\" (enabled: %d)"
 			" (%dx%d@%fHz position %d,%d scale %f transform %d) (bg %s %s)"
@@ -435,6 +508,7 @@ static struct output_config *get_output_config(char *identifier,
 		result = NULL;
 	}
 
+	free(id_on_name);
 	return result;
 }
 
@@ -455,14 +529,12 @@ void apply_output_config_to_outputs(struct output_config *oc) {
 		char *name = sway_output->wlr_output->name;
 		output_get_identifier(id, sizeof(id), sway_output);
 		if (wildcard || !strcmp(name, oc->name) || !strcmp(id, oc->name)) {
-			struct output_config *current = new_output_config(oc->name);
+			struct output_config *current = get_output_config(id, sway_output);
+			if (!current) {
+				// No stored output config matched, apply oc directly
+				sway_log(SWAY_DEBUG, "Applying oc directly");
+				current = new_output_config(oc->name);
 				merge_output_config(current, oc);
-			if (wildcard) {
-				struct output_config *tmp = get_output_config(id, sway_output);
-				if (tmp) {
-					free_output_config(current);
-					current = tmp;
-				}
 			}
 			apply_output_config(current, sway_output);
 			free_output_config(current);