feat(c-bindings): add function to dealloc nodes (#2499)

library/libwaku.h

@@ -35,6 +35,11 @@ int waku_stop(void* ctx,
               WakuCallBack callback,
               void* userData);
 
+// Destroys an instance of a waku node created with waku_new
+int waku_destroy(void* ctx,
+                 WakuCallBack callback,
+                 void* userData);
+
 int waku_version(void* ctx,
                  WakuCallBack callback,
                  void* userData);

library/libwaku.nim

@@ -100,6 +100,20 @@ proc waku_new(configJson: cstring,
 
   return ctx
 
+proc waku_destroy(ctx: ptr Context,
+               callback: WakuCallBack,
+               userData: pointer): cint {.dynlib, exportc.} =
+
+  if isNil(callback):
+    return RET_MISSING_CALLBACK
+
+  waku_thread.stopWakuThread(ctx).isOkOr:
+    let msg = $error
+    callback(RET_ERR, unsafeAddr msg[0], cast[csize_t](len(msg)), userData)
+    return RET_ERR
+
+  return RET_OK
+
 proc waku_version(ctx: ptr Context,
                   callback: WakuCallBack,
                   userData: pointer): cint {.dynlib, exportc.} =

library/waku_thread/waku_thread.nim

@@ -95,12 +95,16 @@ proc createWakuThread*(): Result[ptr Context, string] =
 
   return ok(ctx)
 
-proc stopWakuNodeThread*(ctx: ptr Context) =
+proc stopWakuThread*(ctx: ptr Context): Result[void, string] =
   running.store(false)
+  let fireRes = ctx.reqSignal.fireSync()
+  if fireRes.isErr():
+    return err("error in stopWakuThread: " & $fireRes.error)
   joinThread(ctx.thread)
   discard ctx.reqSignal.close()
   discard ctx.respSignal.close()
   freeShared(ctx)
+  return ok()
 
 proc sendRequestToWakuThread*(ctx: ptr Context,
                               reqType: RequestType,