From 7edaa14c2c822e5b776edaa6534753b258d29488 Mon Sep 17 00:00:00 2001
From: Trumeet <yuuta@yuuta.moe>
Date: Tue, 9 Aug 2022 17:15:45 -0700
Subject: fix(libacron): infinite loop when wic_parse returns 0

This is a rather complicated way to fix backlogging issues. It asks the client to pass partial buffer, and the client also must retry with NULL buffer if ac_receive returns AC_E_AGAIN.
---
 client/helloworld/main.c | 92 ++++++++++++++++++++++++++++++------------------
 1 file changed, 58 insertions(+), 34 deletions(-)

(limited to 'client/helloworld/main.c')

diff --git a/client/helloworld/main.c b/client/helloworld/main.c
index 8b3486b..079b957 100644
--- a/client/helloworld/main.c
+++ b/client/helloworld/main.c
@@ -74,6 +74,8 @@ return 0; \
 
 #endif
 
+static bool ready = false;
+
 static const char *world_name(const enum ac_world world) {
     switch (world) {
         case overworld:
@@ -227,6 +229,39 @@ static int say(void *connection) {
     return 0;
 }
 
+static int process(void *connection, ac_obj_t *obj) {
+    int r;
+    if (!ready) {
+        /* Wait until ready. */
+        enum ac_connection_state state;
+        if ((r = ac_get_state(connection, &state))) {
+            return r;
+        }
+        switch (state) {
+            case AC_STATE_INIT:
+                return 0;
+            case AC_STATE_READY:
+                printf("Connection is established.\n");
+                ready = true;
+                say(connection);
+                return 0;
+            default:
+                fprintf(stderr, "Unexpected state.\n");
+                return 1;
+        }
+    }
+    if (!obj) {
+        return 0;
+    }
+    if (AC_IS_EVENT(obj->type)) {
+        handle_event((ac_event_t *) obj);
+    } else if (AC_IS_RESPONSE(obj->type)) {
+        handle_response((ac_response_t *) obj);
+    }
+    ac_object_free(obj);
+    return 0;
+}
+
 int main(int argc, char **argv) {
     int r;
     if ((r = net_init())) {
@@ -299,11 +334,12 @@ int main(int argc, char **argv) {
     ac_obj_t *obj;
     int nr;
     uint8_t buffer[1000U];
-    size_t bytes;
-    enum ac_connection_state state;
     printf("Waiting until the connection is established.\n");
-    bool ready = false;
+    bool again = false;
     while (1) {
+        size_t read = 0;
+        size_t pos = 0;
+        size_t bytes;
         if ((nr = net_read(&sock, buffer, sizeof(buffer), &bytes, 10))) {
             if (nr == NET_TIMEOUT) {
                 printf("Receive timeout.\n");
@@ -313,42 +349,30 @@ int main(int argc, char **argv) {
             }
         }
         if ((r = lock())) { goto end; }
-        if ((r = ac_receive(connection, buffer, bytes, &obj))) {
-            if ((r = unlock())) { goto end; }
-            goto end;
-        }
-        if (!ready) {
-            /* Wait until ready. */
-            if ((r = ac_get_state(connection, &state))) {
-                if ((r = unlock())) { goto end; }
+        if ((r = ac_receive(connection, buffer, pos, bytes, &obj, &read))) {
+            bool again = r == AC_E_AGAIN;
+            if (!again) {
+                unlock();
                 goto end;
             }
-            switch (state) {
-                case AC_STATE_INIT:
-                    continue;
-                case AC_STATE_READY:
-                    printf("Connection is established.\n");
-                    ready = true;
-                    say(connection);
-                    if ((r = unlock())) { goto end; }
-                    continue;
-                default:
-                    fprintf(stderr, "Unexpected state.\n");
-                    if ((r = unlock())) { goto end; }
-                    goto end;
-            }
         }
+        r = process(connection, obj);
         if ((r = unlock())) { goto end; }
-
-        if (!obj) {
-            continue;
-        }
-        if (AC_IS_EVENT(obj->type)) {
-            handle_event((ac_event_t *) obj);
-        } else if (AC_IS_RESPONSE(obj->type)) {
-            handle_response((ac_response_t *) obj);
+        if (r) { goto end; }
+        while (!again) {
+            if ((r = lock())) { goto end; }
+            if ((r = ac_receive(connection, NULL, 0, 0, &obj, NULL))) {
+                bool again = r == AC_E_AGAIN;
+                if (!again) {
+                    unlock();
+                    goto end;
+                }
+            }
+            again = false;
+            r = process(connection, obj);
+            if ((r = unlock())) { goto end; }
+            if (r) { goto end; }
         }
-        ac_object_free(obj);
     }
     end:
     if (nr) {
-- 
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