Add "uinput" 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 nodes/router.o nodes/modifiers.o nodes/modify_predicate.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 nodes/modifiers.o nodes/modify_predicate.o nodes/uinput.o
 
 all: $(MAIN)
 

config.cfg

@@ -102,6 +102,19 @@ nodes = {
 			predicates = ["touch_held"];
 		};
 	};
+	uinput_output = {
+		type = "uinput";
+		options = {
+			name = "Resulting device";
+			enabled_codes = (
+				{major: "event_type.KEY"; minor: "button_event.LEFT"}
+				,
+				{major: "event_type.KEY"; minor: "button_event.RIGHT"}
+				,
+				{major: "event_type.ABS"; minor: "absolute_axis.X"; data: {minimum: 0; maximum: 3200; resolution: 0}}
+			);
+		};
+	};
 };
 
 channels = ({

nodes/uinput.c

@@ -0,0 +1,177 @@
+#include <libevdev/libevdev-uinput.h>
+#include <stdio.h>
+#include <limits.h>
+#include <errno.h>
+#include "../graph.h"
+#include "../module_registry.h"
+
+typedef struct {
+	GraphNode as_GraphNode;
+	IOHandling subscription;
+	struct libevdev *dev;
+	struct libevdev_uinput *uidev;
+} UinputGraphNode;
+
+typedef struct {
+	enum {
+		CODESPECDATA_NONE,
+		CODESPECDATA_INT,
+		CODESPECDATA_ABSINFO,
+	} which;
+	union {
+		struct input_absinfo as_absinfo;
+		int as_int;
+	};
+} CodeSpecData;
+
+inline static CodeSpecData
+load_code_spec_data(const config_setting_t * setting, InitializationEnvironment * env)
+{
+	CodeSpecData data = {.which = CODESPECDATA_NONE, .as_absinfo = {0, 0, 0, 0, 0, 0}};
+	if (!setting) {
+		return data;
+	}
+	if (config_setting_type(setting) == CONFIG_TYPE_GROUP) {
+		data.which = CODESPECDATA_ABSINFO;
+		data.as_absinfo = (struct input_absinfo) {
+			.value = (int) env_resolve_constant_or(env, config_setting_get_member(setting, "value"), 0),
+			.minimum = (int) env_resolve_constant_or(env, config_setting_get_member(setting, "minimum"), INT_MIN),
+			.maximum = (int) env_resolve_constant_or(env, config_setting_get_member(setting, "maximum"), INT_MAX),
+			.fuzz = (int) env_resolve_constant_or(env, config_setting_get_member(setting, "fuzz"), 0),
+			.flat = (int) env_resolve_constant_or(env, config_setting_get_member(setting, "flat"), 0),
+			.resolution = (int) env_resolve_constant_or(env, config_setting_get_member(setting, "resolution"), 1),
+		};
+	} else if (config_setting_is_scalar(setting)) {
+		data.which = CODESPECDATA_INT;
+		data.as_int = (int) env_resolve_constant(env, setting);
+	}
+	return data;
+}
+
+static void
+load_enable_code(struct libevdev * dev, const config_setting_t * setting, InitializationEnvironment * env)
+{
+	if (!setting) {
+		return;
+	}
+	int type = (int) env_resolve_constant(env, config_setting_get_member(setting, "major"));
+	int code = (int) env_resolve_constant(env, config_setting_get_member(setting, "minor"));
+	CodeSpecData data = load_code_spec_data(config_setting_get_member(setting, "data"), env);
+	const void *data_ptr = NULL;
+	if (data.which == CODESPECDATA_INT) {
+		data_ptr = &data.as_int;
+	} else if (data.which == CODESPECDATA_ABSINFO) {
+		data_ptr = &data.as_absinfo;
+	}
+	libevdev_enable_event_code(dev, type, code, data_ptr);
+}
+
+static bool
+handle_event(EventPositionBase * self, EventNode * event)
+{
+	UinputGraphNode *node = DOWNCAST(UinputGraphNode, GraphNode, DOWNCAST(GraphNode, EventPositionBase, self));
+	libevdev_uinput_write_event(node->uidev, (unsigned int) event->data.code.major, (unsigned int) event->data.code.minor, (int) event->data.payload);
+	event_destroy(event);
+	return true;
+}
+
+static GraphNode *
+create(GraphNodeSpecification * spec, GraphNodeConfig * config, InitializationEnvironment * env)
+{
+	UinputGraphNode * node = T_ALLOC(1, UinputGraphNode);
+	if (!node) {
+		return NULL;
+	}
+
+	const char *name;
+	config_setting_lookup_string(config->options, "name", &name);
+	if (!name) {
+		free(node);
+		return NULL;
+	}
+
+	const config_setting_t *enabled_codes_setting = config_setting_get_member(config->options, "enabled_codes");
+	if (!enabled_codes_setting) {
+		free(node);
+		return NULL;
+	}
+
+	struct libevdev *dev = libevdev_new();
+	if (!dev) {
+		free(node);
+		return NULL;
+	}
+
+	libevdev_set_name(dev, name);
+	size_t codes_length = config_setting_length(enabled_codes_setting);
+	for (size_t i = 0; i < codes_length; ++i) {
+		load_enable_code(dev, config_setting_get_elem(enabled_codes_setting, i), env);
+	}
+
+	struct libevdev_uinput *uidev;
+	int err;
+	if ((err = libevdev_uinput_create_from_device(dev, LIBEVDEV_UINPUT_OPEN_MANAGED, &uidev) != 0)) {
+		libevdev_free(dev);
+		free(node);
+		if (err < 0) {
+			errno = -err;
+		}
+		return NULL;
+	}
+
+	*node = (UinputGraphNode) {
+		.as_GraphNode = {
+			.as_EventPositionBase = {
+				.handle_event = &handle_event,
+				.waiting_new_event = false,
+			},
+			.specification = spec,
+			.inputs = EMPTY_GRAPH_CHANNEL_LIST,
+			.outputs = EMPTY_GRAPH_CHANNEL_LIST,
+		},
+		.dev = dev,
+		.uidev = uidev,
+	};
+	return &node->as_GraphNode;
+}
+
+static void destroy
+(GraphNodeSpecification * self, GraphNode * target)
+{
+	(void) self;
+	UinputGraphNode * node = DOWNCAST(UinputGraphNode, GraphNode, target);
+	if (node->uidev) {
+		libevdev_uinput_destroy(node->uidev);
+		node->uidev = NULL;
+	}
+	if (node->dev) {
+		libevdev_free(node->dev);
+		node->dev = NULL;
+	}
+	free(target);
+}
+
+GraphNodeSpecification nodespec_uinput = (GraphNodeSpecification) {
+	.create = &create,
+	.destroy = &destroy,
+	.register_io = NULL,
+	.name = "uinput",
+	.documentation = "Writes received events to a new uinput device\nAccepts events on any connector\nDoes not send events"
+	                 "\nOption 'name' (required): device name provided to uinput"
+	                 "\nOption 'enabled_codes' (required): collection of event code specifications:"
+	                 "\n\tField 'major' (required): evdev event type"
+	                 "\n\tField 'minor' (required): evdev event code"
+	                 "\n\tField 'data' (optional): integer (useful with major = \"even_type.REP\") or absinfo (useful with major = \"even_type.ABS\"):"
+	                 "\n\t\tField 'value' (optional): initial axis value"
+	                 "\n\t\tField 'minimum' (optional): minimum axis value"
+	                 "\n\t\tField 'maximum' (optional): maximum axis value"
+	                 "\n\t\tField 'fuzz' (optional): axis noise gate"
+	                 "\n\t\tField 'flat' (optional): axis dead zone"
+	                 "\n\t\tField 'resolution' (optional): axis resolution"
+	,
+};
+
+MODULE_CONSTRUCTOR(init)
+{
+	register_graph_node_specification(&nodespec_uinput);
+}