Add "router" node type

Makefile

@@ -12,7 +12,7 @@ CPPFLAGS += $(shell pkg-config --cflags $(DEPS))
 LDLIBS += $(shell pkg-config --libs $(DEPS))
 INTERP ?=
 MAIN = main
-OBJS = main.o events.o processing.o graph.o config.o event_code_names.o hash_table.o module_registry.o event_predicate.o nodes/getchar.o nodes/print.o nodes/evdev.o nodes/tee.o
+OBJS = main.o events.o processing.o graph.o config.o event_code_names.o hash_table.o module_registry.o event_predicate.o nodes/getchar.o nodes/print.o nodes/evdev.o nodes/tee.o nodes/router.o
 
 all: $(MAIN)
 

config.cfg

@@ -39,14 +39,23 @@ nodes = {
 			namespace = "namespaces.clickpad";
 		};
 	};
+	select_key_events = {
+		type = "router";
+		options = {
+			predicates = ["key_event"];
+		};
+	};
 };
 
 channels = ({
 	from: ("stdin", 0);
-	to: ("print", 0);
+	to: ("select_key_events", 0);
 }, {
 	from: ("clickpad", 0);
-	to: ("print", 1);
+	to: ("select_key_events", 1);
+}, {
+	from: ("select_key_events", 0);
+	to: ("print", 0);
 });
 
 // vim: ft=libconfig

nodes/router.c

@@ -0,0 +1,96 @@
+#include "../graph.h"
+#include "../module_registry.h"
+
+typedef struct {
+	GraphNode as_GraphNode;
+	size_t length;
+	EventPredicateHandle * predicates;
+} RouterGraphNode;
+
+static bool
+handle_event(EventPositionBase * self, EventNode * event)
+{
+	RouterGraphNode *node = DOWNCAST(RouterGraphNode, GraphNode, DOWNCAST(GraphNode, EventPositionBase, self));
+	for (size_t i = 0; i < node->length; ++i) {
+		if (i >= node->as_GraphNode.outputs.length) {
+			break;
+		}
+		if (event_predicate_apply(node->predicates[i], event) == EVPREDRES_ACCEPTED) {
+			if (event_replicate(event, 1)) {
+				event->next->position = &node->as_GraphNode.outputs.elements[i]->as_EventPositionBase;
+			}
+		}
+	}
+	event_destroy(event);
+	return true;
+}
+
+static GraphNode *
+create(GraphNodeSpecification * spec, GraphNodeConfig * config, InitializationEnvironment * env)
+{
+	(void) config;
+	(void) env;
+	RouterGraphNode * node = T_ALLOC(1, RouterGraphNode);
+	if (!node) {
+		return NULL;
+	}
+
+	config_setting_t *predicates_setting = config_setting_get_member(config->options, "predicates");
+	if (!predicates_setting) {
+		free(node);
+		return NULL;
+	}
+
+	EventPredicateHandle *predicates = NULL;
+	size_t length = config_setting_length(predicates_setting);
+	if (length > 0) {
+		predicates = T_ALLOC(length, EventPredicateHandle);
+		if (!predicates) {
+			free(node);
+			return NULL;
+		}
+		for (size_t i = 0; i < length; ++i) {
+			predicates[i] = env_resolve_event_predicate(env, config_setting_get_elem(predicates_setting, i));
+		}
+	}
+
+	*node = (RouterGraphNode) {
+		.as_GraphNode = {
+			.as_EventPositionBase = {
+				.handle_event = &handle_event,
+				.waiting_new_event = false,
+			},
+			.specification = spec,
+			.inputs = EMPTY_GRAPH_CHANNEL_LIST,
+			.outputs = EMPTY_GRAPH_CHANNEL_LIST,
+		},
+		.length = length,
+		.predicates = predicates,
+	};
+	return &node->as_GraphNode;
+}
+
+static void destroy
+(GraphNodeSpecification * self, GraphNode * target)
+{
+	(void) self;
+	RouterGraphNode * node = DOWNCAST(RouterGraphNode, GraphNode, target);
+	if (node->predicates) {
+		free(node->predicates);
+		node->predicates = NULL;
+		node->length = 0;
+	}
+	free(target);
+}
+
+GraphNodeSpecification nodespec_router = (GraphNodeSpecification) {
+	.create = &create,
+	.destroy = &destroy,
+	.register_io = NULL,
+	.name = "router",
+};
+
+MODULE_CONSTRUCTOR(init)
+{
+	register_graph_node_specification(&nodespec_router);
+}