Return API description through websocket

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

diff --git a/src/afb-stub-ws.c b/src/afb-stub-ws.c
index c7b4b2e..43837e5 100644 (file)
--- 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
 };
 
 /*****************************************************/