src: adjust connection cleanup logic

Before this, there could be some strange behavior where node
picks up and uses the old socket fd if console.log() is used in an
error event handler. To avoid this, just cleanup first before calling
out to error event handlers...

src/binding.cc

@@ -403,15 +403,15 @@ class Client : public Nan::ObjectWrap {
       if (state != STATE_CLOSED || is_dead) {
         state = STATE_CLOSED;
         Unref();
-        mysql_close(&mysql);
-        if (is_destructing) {
-          if (poll_handle)
+        if (poll_handle) {
+          if (is_destructing)
             uv_poll_stop(poll_handle);
-          FREE(poll_handle);
-        } else if (is_dead)
-          uv_close((uv_handle_t*)poll_handle, cb_close_dummy);
-        else
-          uv_close((uv_handle_t*)poll_handle, cb_close);
+          else if (is_dead)
+            uv_close((uv_handle_t*)poll_handle, cb_close_dummy);
+          else
+            uv_close((uv_handle_t*)poll_handle, cb_close);
+        }
+        mysql_close(&mysql);
         return true;
       }
       return false;
@@ -569,7 +569,8 @@ class Client : public Nan::ObjectWrap {
                   set_keepalive_intvl(mysql_sock, config.tcpkaIntvl);
               }
 
-              poll_handle = (uv_poll_t*)malloc(sizeof(uv_poll_t));
+              if (!poll_handle)
+                poll_handle = (uv_poll_t*)malloc(sizeof(uv_poll_t));
               uv_poll_init_socket(uv_default_loop(), poll_handle, mysql_sock);
               uv_poll_start(poll_handle, UV_READABLE, cb_poll);
               poll_handle->data = this;
@@ -912,7 +913,6 @@ class Client : public Nan::ObjectWrap {
       DBG_LOG("[%lu] cb_close() state=%s\n",
               obj->threadId, state_strings[obj->state]);
 
-      FREE(obj->poll_handle);
       obj->onclose->Call(Nan::New<Object>(obj->context), 0, NULL);
     }
 
@@ -938,7 +938,8 @@ class Client : public Nan::ObjectWrap {
       onconnect->Call(Nan::New<Object>(context), 0, NULL);
     }
 
-    void on_error(bool doClose = false, unsigned int errNo = 0,
+    void on_error(bool doClose = false,
+                  unsigned int errNo = 0,
                   const char* errMsg = NULL) {
       Nan::HandleScope scope;
 
@@ -963,11 +964,11 @@ class Client : public Nan::ObjectWrap {
           Nan::Error(errMsg ? errMsg : mysql_error(&mysql))->ToObject();
       err->Set(Nan::New<String>(code_symbol), Nan::New<Integer>(errCode));
 
-      Local<Value> argv[1] = { err };
-      onerror->Call(Nan::New<Object>(context), 1, argv);
-
       if (doClose || IS_DEAD_ERRNO(errCode))
         close(IS_DEAD_ERRNO(errCode));
+
+      Local<Value> argv[1] = { err };
+      onerror->Call(Nan::New<Object>(context), 1, argv);
     }
 
     void on_row() {