Merge pull request #506 from acrisci/multi-backend-fixes

[wip] multibackend fixes

backend/backend.c

@@ -18,6 +18,7 @@ void wlr_backend_init(struct wlr_backend *backend,
 		const struct wlr_backend_impl *impl) {
 	assert(backend);
 	backend->impl = impl;
+	wl_signal_init(&backend->events.destroy);
 	wl_signal_init(&backend->events.input_add);
 	wl_signal_init(&backend->events.input_remove);
 	wl_signal_init(&backend->events.output_add);
@@ -32,6 +33,11 @@ bool wlr_backend_start(struct wlr_backend *backend) {
 }
 
 void wlr_backend_destroy(struct wlr_backend *backend) {
+	if (!backend) {
+		return;
+	}
+
+	wl_signal_emit(&backend->events.destroy, backend);
 	if (backend->impl && backend->impl->destroy) {
 		backend->impl->destroy(backend);
 	} else {
@@ -70,39 +76,46 @@ static struct wlr_backend *attempt_wl_backend(struct wl_display *display) {
 }
 
 struct wlr_backend *wlr_backend_autocreate(struct wl_display *display) {
-	struct wlr_backend *backend;
+	struct wlr_backend *backend = wlr_multi_backend_create(display);
+	if (!backend) {
+		wlr_log(L_ERROR, "could not allocate multibackend");
+		return NULL;
+	}
+
 	if (getenv("WAYLAND_DISPLAY") || getenv("_WAYLAND_DISPLAY")) {
-		backend = attempt_wl_backend(display);
-		if (backend) {
+		struct wlr_backend *wl_backend = attempt_wl_backend(display);
+		if (wl_backend) {
+			wlr_multi_backend_add(backend, wl_backend);
 			return backend;
 		}
 	}
 
 	const char *x11_display = getenv("DISPLAY");
 	if (x11_display) {
-		return wlr_x11_backend_create(display, x11_display);
+		struct wlr_backend *x11_backend =
+			wlr_x11_backend_create(display, x11_display);
+		wlr_multi_backend_add(backend, x11_backend);
+		return backend;
 	}
 
 	// Attempt DRM+libinput
-
 	struct wlr_session *session = wlr_session_create(display);
 	if (!session) {
 		wlr_log(L_ERROR, "Failed to start a DRM session");
+		wlr_backend_destroy(backend);
 		return NULL;
 	}
 
-	backend = wlr_multi_backend_create(display, session);
-	if (!backend) {
-		goto error_session;
-	}
-
 	struct wlr_backend *libinput = wlr_libinput_backend_create(display, session);
-	if (!libinput) {
-		goto error_multi;
+	if (libinput) {
+		wlr_multi_backend_add(backend, libinput);
+	} else {
+		wlr_log(L_ERROR, "Failed to start libinput backend");
+		wlr_backend_destroy(backend);
+		wlr_session_destroy(session);
+		return NULL;
 	}
 
-	wlr_multi_backend_add(backend, libinput);
-
 	int gpus[8];
 	size_t num_gpus = wlr_session_find_gpus(session, 8, gpus);
 	struct wlr_backend *primary_drm = NULL;
@@ -125,16 +138,13 @@ struct wlr_backend *wlr_backend_autocreate(struct wl_display *display) {
 
 	if (!primary_drm) {
 		wlr_log(L_ERROR, "Failed to open any DRM device");
-		goto error_multi;
+		wlr_backend_destroy(libinput);
+		wlr_session_destroy(session);
+		wlr_backend_destroy(backend);
+		return NULL;
 	}
 
 	return backend;
-
-error_multi:
-	wlr_backend_destroy(backend);
-error_session:
-	wlr_session_destroy(session);
-	return NULL;
 }
 
 uint32_t usec_to_msec(uint64_t usec) {

backend/drm/backend.c

@@ -174,3 +174,8 @@ error_fd:
 	free(drm);
 	return NULL;
 }
+
+struct wlr_session *wlr_drm_backend_get_session(struct wlr_backend *backend) {
+	struct wlr_drm_backend *drm = (struct wlr_drm_backend *)backend;
+	return drm->session;
+}

backend/multi/backend.c

@@ -5,6 +5,7 @@
 #include <wlr/backend/session.h>
 #include <wlr/util/log.h>
 #include "backend/multi.h"
+#include "backend/drm/drm.h"
 
 struct subbackend_state {
 	struct wlr_backend *backend;
@@ -13,6 +14,7 @@ struct subbackend_state {
 	struct wl_listener input_remove;
 	struct wl_listener output_add;
 	struct wl_listener output_remove;
+	struct wl_listener backend_destroy;
 	struct wl_list link;
 };
 
@@ -28,13 +30,21 @@ static bool multi_backend_start(struct wlr_backend *wlr_backend) {
 	return true;
 }
 
+static void subbackend_state_destroy(struct subbackend_state *sub) {
+	wl_list_remove(&sub->input_add.link);
+	wl_list_remove(&sub->input_remove.link);
+	wl_list_remove(&sub->output_add.link);
+	wl_list_remove(&sub->output_remove.link);
+	wl_list_remove(&sub->backend_destroy.link);
+	wl_list_remove(&sub->link);
+	free(sub);
+}
+
 static void multi_backend_destroy(struct wlr_backend *wlr_backend) {
 	struct wlr_multi_backend *backend = (struct wlr_multi_backend *)wlr_backend;
-	wl_list_remove(&backend->display_destroy.link);
 	struct subbackend_state *sub, *next;
 	wl_list_for_each_safe(sub, next, &backend->backends, link) {
 		wlr_backend_destroy(sub->backend);
-		free(sub);
 	}
 	free(backend);
 }
@@ -60,11 +70,10 @@ struct wlr_backend_impl backend_impl = {
 static void handle_display_destroy(struct wl_listener *listener, void *data) {
 	struct wlr_multi_backend *backend =
 		wl_container_of(listener, backend, display_destroy);
-	multi_backend_destroy(&backend->backend);
+	multi_backend_destroy((struct wlr_backend*)backend);
 }
 
-struct wlr_backend *wlr_multi_backend_create(struct wl_display *display,
-		struct wlr_session *session) {
+struct wlr_backend *wlr_multi_backend_create(struct wl_display *display) {
 	struct wlr_multi_backend *backend =
 		calloc(1, sizeof(struct wlr_multi_backend));
 	if (!backend) {
@@ -72,12 +81,14 @@ struct wlr_backend *wlr_multi_backend_create(struct wl_display *display,
 		return NULL;
 	}
 
-	backend->session = session;
 	wl_list_init(&backend->backends);
 	wlr_backend_init(&backend->backend, &backend_impl);
 
-	session->display_destroy.notify = handle_display_destroy;
-	wl_display_add_destroy_listener(display, &session->display_destroy);
+	wl_signal_init(&backend->events.backend_add);
+	wl_signal_init(&backend->events.backend_remove);
+
+	backend->display_destroy.notify = handle_display_destroy;
+	wl_display_add_destroy_listener(display, &backend->display_destroy);
 
 	return &backend->backend;
 }
@@ -110,11 +121,34 @@ static void output_remove_reemit(struct wl_listener *listener, void *data) {
 	wl_signal_emit(&state->container->events.output_remove, data);
 }
 
+static void handle_subbackend_destroy(struct wl_listener *listener,
+		void *data) {
+	struct subbackend_state *state = wl_container_of(listener,
+			state, backend_destroy);
+	subbackend_state_destroy(state);
+}
+
+static struct subbackend_state *multi_backend_get_subbackend(struct wlr_multi_backend *multi,
+		struct wlr_backend *backend) {
+	struct subbackend_state *sub = NULL;
+	wl_list_for_each(sub, &multi->backends, link) {
+		if (sub->backend == backend) {
+			return sub;
+		}
+	}
+	return NULL;
+}
+
 void wlr_multi_backend_add(struct wlr_backend *_multi,
 		struct wlr_backend *backend) {
 	assert(wlr_backend_is_multi(_multi));
-
 	struct wlr_multi_backend *multi = (struct wlr_multi_backend *)_multi;
+
+	if (multi_backend_get_subbackend(multi, backend)) {
+		// already added
+		return;
+	}
+
 	struct subbackend_state *sub;
 	if (!(sub = calloc(1, sizeof(struct subbackend_state)))) {
 		wlr_log(L_ERROR, "Could not add backend: allocation failed");
@@ -125,20 +159,53 @@ void wlr_multi_backend_add(struct wlr_backend *_multi,
 	sub->backend = backend;
 	sub->container = &multi->backend;
 
-	sub->input_add.notify = input_add_reemit;
-	sub->input_remove.notify = input_remove_reemit;
-	sub->output_add.notify = output_add_reemit;
-	sub->output_remove.notify = output_remove_reemit;
+	wl_signal_add(&backend->events.destroy, &sub->backend_destroy);
+	sub->backend_destroy.notify = handle_subbackend_destroy;
 
 	wl_signal_add(&backend->events.input_add, &sub->input_add);
+	sub->input_add.notify = input_add_reemit;
+
 	wl_signal_add(&backend->events.input_remove, &sub->input_remove);
+	sub->input_remove.notify = input_remove_reemit;
+
 	wl_signal_add(&backend->events.output_add, &sub->output_add);
+	sub->output_add.notify = output_add_reemit;
+
 	wl_signal_add(&backend->events.output_remove, &sub->output_remove);
+	sub->output_remove.notify = output_remove_reemit;
+
+	wl_signal_emit(&multi->events.backend_add, backend);
+}
+
+void wlr_multi_backend_remove(struct wlr_backend *_multi,
+		struct wlr_backend *backend) {
+	assert(wlr_backend_is_multi(_multi));
+	struct wlr_multi_backend *multi = (struct wlr_multi_backend *)_multi;
+
+	struct subbackend_state *sub =
+		multi_backend_get_subbackend(multi, backend);
+
+	if (sub) {
+		wl_signal_emit(&multi->events.backend_remove, backend);
+		subbackend_state_destroy(sub);
+	}
 }
 
 struct wlr_session *wlr_multi_get_session(struct wlr_backend *_backend) {
 	assert(wlr_backend_is_multi(_backend));
 
 	struct wlr_multi_backend *backend = (struct wlr_multi_backend *)_backend;
-	return backend->session;
+	struct subbackend_state *sub;
+	wl_list_for_each(sub, &backend->backends, link) {
+		if (wlr_backend_is_drm(sub->backend)) {
+			return wlr_drm_backend_get_session(sub->backend);
+		}
+	}
+	return NULL;
+}
+
+bool wlr_multi_is_empty(struct wlr_backend *_backend) {
+	assert(wlr_backend_is_multi(_backend));
+	struct wlr_multi_backend *backend = (struct wlr_multi_backend *)_backend;
+	return wl_list_length(&backend->backends) < 1;
 }

include/backend/drm/drm.h

@@ -143,4 +143,6 @@ int wlr_drm_event(int fd, uint32_t mask, void *data);
 
 void wlr_drm_connector_start_renderer(struct wlr_drm_connector *conn);
 
+struct wlr_session *wlr_drm_backend_get_session(struct wlr_backend *backend);
+
 #endif

include/backend/multi.h

@@ -9,10 +9,14 @@
 struct wlr_multi_backend {
 	struct wlr_backend backend;
 
-	struct wlr_session *session;
 	struct wl_list backends;
 
 	struct wl_listener display_destroy;
+
+	struct {
+		struct wl_signal backend_add;
+		struct wl_signal backend_remove;
+	} events;
 };
 
 #endif

include/wlr/backend.h

@@ -11,6 +11,7 @@ struct wlr_backend {
 	const struct wlr_backend_impl *impl;
 
 	struct {
+		struct wl_signal destroy;
 		struct wl_signal input_add;
 		struct wl_signal input_remove;
 		struct wl_signal output_add;

include/wlr/backend/multi.h

@@ -4,13 +4,18 @@
 #include <wlr/backend.h>
 #include <wlr/backend/session.h>
 
-struct wlr_backend *wlr_multi_backend_create(struct wl_display *display,
-	struct wlr_session *session);
+struct wlr_backend *wlr_multi_backend_create(struct wl_display *display);
+
 void wlr_multi_backend_add(struct wlr_backend *multi,
 	struct wlr_backend *backend);
 
+void wlr_multi_backend_remove(struct wlr_backend *multi,
+	struct wlr_backend *backend);
+
 bool wlr_backend_is_multi(struct wlr_backend *backend);
 
 struct wlr_session *wlr_multi_get_session(struct wlr_backend *base);
 
+bool wlr_multi_is_empty(struct wlr_backend *backend);
+
 #endif

rootston/main.c

@@ -5,6 +5,7 @@
 #include <wayland-server.h>
 #include <wlr/backend.h>
 #include <wlr/backend/headless.h>
+#include <wlr/backend/multi.h>
 #include <wlr/render.h>
 #include <wlr/render/gles2.h>
 #include <wlr/util/log.h>
@@ -30,7 +31,13 @@ int main(int argc, char **argv) {
 	assert(server.wl_display = wl_display_create());
 	assert(server.wl_event_loop = wl_display_get_event_loop(server.wl_display));
 
-	assert(server.backend = wlr_backend_autocreate(server.wl_display));
+	server.backend = wlr_backend_autocreate(server.wl_display);
+
+	if (server.backend == NULL) {
+		wlr_log(L_ERROR, "could not start backend");
+		wlr_backend_destroy(server.backend);
+		return 1;
+	}
 
 	assert(server.renderer = wlr_gles2_renderer_create(server.backend));
 	server.data_device_manager =