Core/DBLayer: Added new async query callback api

src/server/database/Database/QueryCallback.cpp

@@ -0,0 +1,98 @@
+/*
+ * Copyright (C) 2008-2017 TrinityCore <http://www.trinitycore.org/>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "QueryCallback.h"
+
+QueryCallbackNew::QueryCallbackNew(std::future<QueryResult>&& result) : _string(std::move(result)), _isPrepared(false)
+{
+}
+
+QueryCallbackNew::QueryCallbackNew(std::future<PreparedQueryResult>&& result) : _prepared(std::move(result)), _isPrepared(true)
+{
+}
+
+QueryCallbackNew::QueryCallbackNew(QueryCallbackNew&& right)
+{
+    MoveFrom(std::move(right));
+}
+
+QueryCallbackNew& QueryCallbackNew::operator=(QueryCallbackNew&& right)
+{
+    MoveFrom(std::move(right));
+    return *this;
+}
+
+QueryCallbackNew::~QueryCallbackNew()
+{
+    DestroyCurrentMember();
+}
+
+QueryCallbackNew&& QueryCallbackNew::WithCallback(std::function<void(QueryResult)>&& callback)
+{
+    ASSERT(!_isPrepared, "Attempted to set callback function for string query on a prepared async query");
+    _string.Callback = std::move(callback);
+    return std::move(*this);
+}
+
+QueryCallbackNew&& QueryCallbackNew::WithPreparedCallback(std::function<void(PreparedQueryResult)>&& callback)
+{
+    ASSERT(_isPrepared, "Attempted to set callback function for prepared query on a string async query");
+    _prepared.Callback = std::move(callback);
+    return std::move(*this);
+}
+
+QueryCallbackNew::Status QueryCallbackNew::InvokeIfReady()
+{
+    if (!_isPrepared)
+    {
+        if (_string.Result.valid() && _string.Result.wait_for(std::chrono::seconds(0)) == std::future_status::ready)
+        {
+            std::function<void(QueryResult)> cb(std::move(_string.Callback));
+            cb(_string.Result.get());
+            return !_string.Callback ? Completed : NextStep;
+        }
+    }
+    else
+    {
+        if (_prepared.Result.valid() && _prepared.Result.wait_for(std::chrono::seconds(0)) == std::future_status::ready)
+        {
+            std::function<void(PreparedQueryResult)> cb(std::move(_prepared.Callback));
+            cb(_prepared.Result.get());
+            return !_prepared.Callback ? Completed : NextStep;
+        }
+    }
+
+    return NotReady;
+}
+
+void QueryCallbackNew::MoveFrom(QueryCallbackNew&& other)
+{
+    DestroyCurrentMember();
+    _isPrepared = other._isPrepared;
+    if (!_isPrepared)
+        _string = std::move(other._string);
+    else
+        _prepared = std::move(other._prepared);
+}
+
+void QueryCallbackNew::DestroyCurrentMember()
+{
+    if (!_isPrepared)
+        _string.~String();
+    else
+        _prepared.~Prepared();
+}