binding: navigation: rewrite of navigation binding

To remove dependency on DBus the binding needed to be rewritten to
output pure JSON output to subscribed consumers.

Bug-AGL: SPEC-2880
Change-Id: Ie85dfccd42ca36119116a0fbfb16bf4e96efc184
Signed-off-by: Matt Ranostay <matt.ranostay@konsulko.com>

1 files changed, 245 insertions, 0 deletions

diff --git a/binding/navigation-api.c b/binding/navigation-api.c
new file mode 100644
index 0000000..d9ea285
--- /dev/null
+++ b/binding/navigation-api.c
@@ -0,0 +1,245 @@
+/*
+ * Copyright (C) 2019 Konsulko Group
+ * Author: Matt Ranostay <matt.ranostay@konsulko.com>
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define _GNU_SOURCE
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/time.h>
+#include <time.h>
+
+#include <glib.h>
+#include <glib/gstdio.h>
+#include <gio/gio.h>
+#include <json-c/json.h>
+
+#define AFB_BINDING_VERSION 3
+#include <afb/afb-binding.h>
+
+#include "navigation-api.h"
+
+struct navigation_state *navigation_get_userdata(afb_req_t request) {
+	afb_api_t api = afb_req_get_api(request);
+	return afb_api_get_userdata(api);
+}
+
+static afb_event_t get_event_from_value(struct navigation_state *ns,
+			const char *value)
+{
+	if (!g_strcmp0(value, "status"))
+		return ns->status_event;
+
+	if (!g_strcmp0(value, "position"))
+		return ns->position_event;
+
+	if (!g_strcmp0(value, "waypoints"))
+		return ns->waypoints_event;
+
+	return NULL;
+}
+
+static json_object **get_storage_from_value(struct navigation_state *ns,
+			const char *value)
+{
+	if (!g_strcmp0(value, "status"))
+		return &ns->status_storage;
+
+	if (!g_strcmp0(value, "position"))
+		return &ns->position_storage;
+
+	if (!g_strcmp0(value, "waypoints"))
+		return &ns->waypoints_storage;
+
+	return NULL;
+}
+
+static void navigation_subscribe_unsubscribe(afb_req_t request,
+		gboolean unsub)
+{
+	struct navigation_state *ns = navigation_get_userdata(request);
+	json_object *jresp = json_object_new_object();
+	const char *value;
+	afb_event_t event;
+	int rc;
+
+	value = afb_req_value(request, "value");
+	if (!value) {
+		afb_req_fail_f(request, "failed", "Missing \"value\" event");
+		return;
+	}
+
+	event = get_event_from_value(ns, value);
+	if (!event) {
+		afb_req_fail_f(request, "failed", "Bad \"value\" event \"%s\"",
+				value);
+		return;
+	}
+
+	if (!unsub) {
+		json_object *storage;
+		rc = afb_req_subscribe(request, event);
+
+		g_rw_lock_reader_lock(&ns->rw_lock);
+		storage = *get_storage_from_value(ns, value);
+		if (storage) {
+			// increment reference counter, and send out cached value
+			json_object_get(storage);
+			afb_event_push(event, storage);
+		}
+		g_rw_lock_reader_unlock(&ns->rw_lock);
+	} else {
+		rc = afb_req_unsubscribe(request, event);
+	}
+	if (rc != 0) {
+		afb_req_fail_f(request, "failed",
+					"%s error on \"value\" event \"%s\"",
+					!unsub ? "subscribe" : "unsubscribe",
+					value);
+		return;
+	}
+
+	afb_req_success_f(request, jresp, "Navigation %s to event \"%s\"",
+			!unsub ? "subscribed" : "unsubscribed",
+			value);
+}
+
+static void subscribe(afb_req_t request)
+{
+	navigation_subscribe_unsubscribe(request, FALSE);
+}
+
+static void unsubscribe(afb_req_t request)
+{
+	navigation_subscribe_unsubscribe(request, TRUE);
+}
+
+static void broadcast(afb_req_t request, const char *name, gboolean cache)
+{
+	struct navigation_state *ns = navigation_get_userdata(request);
+	afb_event_t event = get_event_from_value(ns, name);
+	json_object *jresp = afb_req_json(request);
+
+	if (cache) {
+		json_object **storage = get_storage_from_value(ns, name);
+
+		g_rw_lock_writer_lock(&ns->rw_lock);
+
+		if (*storage)
+			json_object_put(*storage);
+
+		// increment reference for storage
+		json_object_get(jresp);
+		*storage = jresp;
+
+		g_rw_lock_writer_unlock(&ns->rw_lock);
+	}
+
+	// increment reference for event
+	json_object_get(jresp);
+	afb_event_push(event, jresp);
+}
+
+static void broadcast_status(afb_req_t request)
+{
+	broadcast(request, "status", TRUE);
+
+	afb_req_success(request, NULL, "Broadcast status send");
+}
+
+static void broadcast_position(afb_req_t request)
+{
+	const char *position = afb_req_value(request, "position");
+	gboolean cache = FALSE;
+
+	// only send out a car position event on subscribe
+	if (position && !g_strcmp0(position, "car"))
+		cache = TRUE;
+
+	broadcast(request, "position", cache);
+
+	afb_req_success(request, NULL, "Broadcast position send");
+}
+
+static void broadcast_waypoints(afb_req_t request)
+{
+	broadcast(request, "waypoints", TRUE);
+
+	afb_req_success(request, NULL, "Broadcast waypoints send");
+}
+
+static int init(afb_api_t api)
+{
+	struct navigation_state *ns;
+
+	ns = g_try_malloc0(sizeof(*ns));
+	if (!ns) {
+		AFB_ERROR("out of memory allocating navigation state");
+		return -ENOMEM;
+	}
+
+	ns->status_event = afb_daemon_make_event("status");
+	ns->position_event = afb_daemon_make_event("position");
+	ns->waypoints_event = afb_daemon_make_event("waypoints");
+
+	if (!afb_event_is_valid(ns->status_event) ||
+	    !afb_event_is_valid(ns->position_event) ||
+	    !afb_event_is_valid(ns->waypoints_event)) {
+		AFB_ERROR("Cannot create events");
+		return -EINVAL;
+	}
+
+	afb_api_set_userdata(api, ns);
+
+	g_rw_lock_init(&ns->rw_lock);
+
+	return 0;
+}
+
+static const afb_verb_t binding_verbs[] = {
+	{
+		.verb = "subscribe",
+		.callback = subscribe,
+		.info = "Subscribe to event"
+	}, {
+		.verb = "unsubscribe",
+		.callback = unsubscribe,
+		.info = "Unsubscribe to event"
+	}, {
+		.verb = "broadcast_status",
+		.callback = broadcast_status,
+		.info = "Allows clients to broadcast status events"
+	}, {
+		.verb = "broadcast_position",
+		.callback = broadcast_position,
+		.info = "Broadcast out position event"
+	}, {
+		.verb = "broadcast_waypoints",
+		.callback = broadcast_waypoints,
+		.info = "Broadcast out waypoint event"
+	},
+	{}
+};
+
+/*
+ * description of the binding for afb-daemon
+ */
+const afb_binding_t afbBindingV3 = {
+	.api = "navigation",
+	.verbs = binding_verbs,
+	.init = init,
+};