Return API description through websocket

Change-Id: Iab10ed193bf6f6fc4240f6856c5835e35cd85dfa
Signed-off-by: José Bollo <jose.bollo@iot.bzh>

1 files changed, 180 insertions, 3 deletions

diff --git a/src/afb-stub-ws.c b/src/afb-stub-ws.c
index c7b4b2ec..43837e58 100644
--- a/src/afb-stub-ws.c
+++ b/src/afb-stub-ws.c
@@ -50,9 +50,8 @@
 #include "afb-evt.h"
 #include "afb-xreq.h"
 #include "verbose.h"
+#include "jobs.h"
 
-struct client_call;
-struct client_event;
 struct afb_stub_ws;
 
 /************** constants for protocol definition *************************/
@@ -68,6 +67,8 @@ struct afb_stub_ws;
 #define CHAR_FOR_EVT_UNSUBSCRIBE  'U'
 #define CHAR_FOR_SUBCALL_CALL     'B'
 #define CHAR_FOR_SUBCALL_REPLY    'R'
+#define CHAR_FOR_DESCRIBE         'D'
+#define CHAR_FOR_DESCRIPTION      'd'
 
 /******************* handling subcalls *****************************/
 
@@ -122,6 +123,27 @@ struct client_event
 	int refcount;
 };
 
+/*
+ * structure for recording describe requests
+ */
+struct client_describe
+{
+	struct client_describe *next;
+	struct afb_stub_ws *stubws;
+	struct jobloop *jobloop;
+	struct json_object *result;
+	uint32_t descid;
+};
+
+/*
+ * structure for jobs of describing
+ */
+struct server_describe
+{
+	struct afb_stub_ws *stubws;
+	uint32_t descid;
+};
+
 /******************* client description part for server *****************************/
 
 struct afb_stub_ws
@@ -153,6 +175,9 @@ struct afb_stub_ws
 	/* pending subcalls (server side) */
 	struct server_subcall *subcalls;
 
+	/* pending description (client side) */
+	struct client_describe *describes;
+
 	/* apiset */
 	struct afb_apiset *apiset;
 
@@ -769,6 +794,31 @@ static void client_subcall(struct afb_stub_ws *stubws, struct readbuf *rb)
 	}
 }
 
+/* pushs an event */
+static void client_on_description(struct afb_stub_ws *stubws, struct readbuf *rb)
+{
+	uint32_t descid;
+	struct client_describe *desc;
+	struct json_object *object;
+
+	if (!readbuf_uint32(rb, &descid))
+		ERROR("unreadable description");
+	else {
+		desc = stubws->describes;
+		while (desc && desc->descid != descid)
+			desc = desc->next;
+		if (desc == NULL)
+			ERROR("unexpected description");
+		else {
+			if (readbuf_object(rb, &object))
+				desc->result = object;
+			else
+				ERROR("bad description");
+			jobs_leave(desc->jobloop);
+		}
+	}
+}
+
 /* callback when receiving binary data */
 static void client_on_binary(void *closure, char *data, size_t size)
 {
@@ -805,6 +855,9 @@ static void client_on_binary(void *closure, char *data, size_t size)
 		case CHAR_FOR_SUBCALL_CALL: /* subcall */
 			client_subcall(stubws, &rb);
 			break;
+		case CHAR_FOR_DESCRIPTION: /* description */
+			client_on_description(stubws, &rb);
+			break;
 		default: /* unexpected message */
 			/* TODO: close the connection */
 			break;
@@ -866,6 +919,70 @@ end:
 	pthread_mutex_unlock(&stubws->mutex);
 }
 
+static void client_send_describe_cb(int signum, void *closure, struct jobloop *jobloop)
+{
+	struct client_describe *desc = closure;
+	struct writebuf wb = { .count = 0 };
+
+	if (!signum) {
+		/* record the jobloop */
+		desc->jobloop = jobloop;
+
+		/* send */
+		if (writebuf_char(&wb, CHAR_FOR_DESCRIBE)
+		 && writebuf_uint32(&wb, desc->descid)
+		 && afb_ws_binary_v(desc->stubws->ws, wb.iovec, wb.count) >= 0)
+			return;
+	}
+	jobs_leave(jobloop);
+}
+
+/* get the description */
+static struct json_object *client_describe_cb(void * closure)
+{
+	struct client_describe desc, *d;
+	struct afb_stub_ws *stubws = closure;
+
+	/* fill in stack the description of the task */
+	pthread_mutex_lock(&stubws->mutex);
+	desc.result = NULL;
+	desc.descid = ptr2id(&desc);
+	d = stubws->describes;
+	while (d) {
+		if (d->descid != desc.descid)
+			d = d->next;
+		else {
+			desc.descid++;
+			d = stubws->describes;
+		}
+	}
+	desc.stubws = stubws;
+	desc.next = stubws->describes;
+	stubws->describes = &desc;
+	pthread_mutex_unlock(&stubws->mutex);
+
+	/* synchronous job: send the request and wait its result */
+	jobs_enter(NULL, 0, client_send_describe_cb, &desc);
+
+	/* unlink and send the result */
+	pthread_mutex_lock(&stubws->mutex);
+	d = stubws->describes;
+	if (d == &desc)
+		stubws->describes = desc.next;
+	else {
+		while (d) {
+			if (d->next != &desc)
+				d = d->next;
+			else {
+				d->next = desc.next;
+				d = NULL;
+			}
+		}
+	}
+	pthread_mutex_unlock(&stubws->mutex);
+	return desc.result;
+}
+
 /******************* client description part for server *****************************/
 
 /* on call, propagate it to the ws service */
@@ -953,6 +1070,62 @@ static void server_on_subcall_reply(struct afb_stub_ws *stubws, struct readbuf *
 	json_object_put(object);
 }
 
+static void server_send_description(struct afb_stub_ws *stubws, uint32_t descid, struct json_object *descobj)
+{
+	struct writebuf wb = { .count = 0 };
+
+	if (!writebuf_char(&wb, CHAR_FOR_DESCRIPTION)
+	 || !writebuf_uint32(&wb, descid)
+	 || !writebuf_object(&wb, descobj)
+         || afb_ws_binary_v(stubws->ws, wb.iovec, wb.count) < 0)
+		ERROR("can't send description");
+}
+
+static void server_describe_job(int signum, void *closure)
+{
+	struct afb_api api;
+	struct json_object *obj;
+	struct server_describe *desc = closure;
+
+	/* get the description if possible */
+	obj = NULL;
+	if (!signum
+	 && !afb_apiset_get(desc->stubws->apiset, desc->stubws->apiname, &api)
+	 && api.itf->describe) {
+		obj = api.itf->describe(api.closure);
+	}
+
+	/* send it */
+	server_send_description(desc->stubws, desc->descid, obj);
+	json_object_put(obj);
+	afb_stub_ws_unref(desc->stubws);
+	free(desc);
+}
+
+/* on describe, propagate it to the ws service */
+static void server_on_describe(struct afb_stub_ws *stubws, struct readbuf *rb)
+{
+
+	uint32_t descid;
+	struct server_describe *desc;
+
+	/* reads the descid */
+	if (readbuf_uint32(rb, &descid)) {
+		/* create asynchronous job */
+		desc = malloc(sizeof *desc);
+		if (desc) {
+			desc->descid = descid;
+			desc->stubws = stubws;
+			afb_stub_ws_addref(stubws);
+			if (jobs_queue(NULL, 0, server_describe_job, desc) < 0)
+				server_describe_job(0, desc);
+			return;
+		}
+		server_send_description(stubws, descid, NULL);
+	}
+	ERROR("can't provide description");
+}
+
 /* callback when receiving binary data */
 static void server_on_binary(void *closure, char *data, size_t size)
 {
@@ -965,6 +1138,9 @@ static void server_on_binary(void *closure, char *data, size_t size)
 		case CHAR_FOR_SUBCALL_REPLY:
 			server_on_subcall_reply(closure, &rb);
 			break;
+		case CHAR_FOR_DESCRIBE:
+			server_on_describe(closure, &rb);
+			break;
 		default: /* unexpected message */
 			/* TODO: close the connection */
 			break;
@@ -1070,7 +1246,8 @@ static const struct afb_ws_itf server_ws_itf =
 };
 
 static struct afb_api_itf ws_api_itf = {
-	.call = client_call_cb
+	.call = client_call_cb,
+	.describe = client_describe_cb
 };
 
 /*****************************************************/