QueryCallback.cpp

Go to the documentation of this file.

/*
 * This file is part of the TrinityCore Project. See AUTHORS file for Copyright information
 *
 * 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"
#include "Errors.h"
 
template<typename T, typename... Args>
inline void Construct(T& t, Args&&... args)
{
 new (&t) T(std::forward<Args>(args)...);
}
 
template<typename T>
inline void Destroy(T& t)
{
 t.~T();
}
 
template<typename T>
inline void ConstructActiveMember(T* obj)
{
 if (!obj->_isPrepared)
 Construct(obj->_string);
 else
 Construct(obj->_prepared);
}
 
template<typename T>
inline void DestroyActiveMember(T* obj)
{
 if (!obj->_isPrepared)
 Destroy(obj->_string);
 else
 Destroy(obj->_prepared);
}
 
template<typename T>
inline void MoveFrom(T* to, T&& from)
{
 ASSERT(to->_isPrepared == from._isPrepared);
 
 if (!to->_isPrepared)
 to->_string = std::move(from._string);
 else
 to->_prepared = std::move(from._prepared);
}
 
struct QueryCallback::QueryCallbackData
{
public:
 friend class QueryCallback;
 
 QueryCallbackData(std::function<void(QueryCallback&, QueryResult)>&& callback) : _string(std::move(callback)), _isPrepared(false) { }
 QueryCallbackData(std::function<void(QueryCallback&, PreparedQueryResult)>&& callback) : _prepared(std::move(callback)), _isPrepared(true) { }
 QueryCallbackData(QueryCallbackData&& right) noexcept
 {
 _isPrepared = right._isPrepared;
 ConstructActiveMember(this);
 MoveFrom(this, std::move(right));
 }
 QueryCallbackData& operator=(QueryCallbackData&& right) noexcept
 {
 if (this != &right)
 {
 if (_isPrepared != right._isPrepared)
 {
 DestroyActiveMember(this);
 _isPrepared = right._isPrepared;
 ConstructActiveMember(this);
 }
 MoveFrom(this, std::move(right));
 }
 return *this;
 }
 ~QueryCallbackData() { DestroyActiveMember(this); }
 
private:
 QueryCallbackData(QueryCallbackData const&) = delete;
 QueryCallbackData& operator=(QueryCallbackData const&) = delete;
 
 template<typename T> friend void ConstructActiveMember(T* obj);
 template<typename T> friend void DestroyActiveMember(T* obj);
 template<typename T> friend void MoveFrom(T* to, T&& from);
 
 union
 {
 std::function<void(QueryCallback&, QueryResult)> _string;
 std::function<void(QueryCallback&, PreparedQueryResult)> _prepared;
 };
 bool _isPrepared;
};
 
// Not using initialization lists to work around segmentation faults when compiling with clang without precompiled headers
QueryCallback::QueryCallback(std::future<QueryResult>&& result)
{
 _isPrepared = false;
 Construct(_string, std::move(result));
}
 
QueryCallback::QueryCallback(std::future<PreparedQueryResult>&& result)
{
 _isPrepared = true;
 Construct(_prepared, std::move(result));
}
 
QueryCallback::QueryCallback(QueryCallback&& right) noexcept
{
 _isPrepared = right._isPrepared;
 ConstructActiveMember(this);
 MoveFrom(this, std::move(right));
 _callbacks = std::move(right._callbacks);
}
 
QueryCallback& QueryCallback::operator=(QueryCallback&& right) noexcept
{
 if (this != &right)
 {
 if (_isPrepared != right._isPrepared)
 {
 DestroyActiveMember(this);
 _isPrepared = right._isPrepared;
 ConstructActiveMember(this);
 }
 MoveFrom(this, std::move(right));
 _callbacks = std::move(right._callbacks);
 }
 return *this;
}
 
QueryCallback::~QueryCallback()
{
 DestroyActiveMember(this);
}
 
QueryCallback&& QueryCallback::WithCallback(std::function<void(QueryResult)>&& callback)
{
 return WithChainingCallback([callback](QueryCallback& /*this*/, QueryResult result) { callback(std::move(result)); });
}
 
QueryCallback&& QueryCallback::WithPreparedCallback(std::function<void(PreparedQueryResult)>&& callback)
{
 return WithChainingPreparedCallback([callback](QueryCallback& /*this*/, PreparedQueryResult result) { callback(std::move(result)); });
}
 
QueryCallback&& QueryCallback::WithChainingCallback(std::function<void(QueryCallback&, QueryResult)>&& callback)
{
 ASSERT(!_callbacks.empty() || !_isPrepared, "Attempted to set callback function for string query on a prepared async query");
 _callbacks.emplace(std::move(callback));
 return std::move(*this);
}
 
QueryCallback&& QueryCallback::WithChainingPreparedCallback(std::function<void(QueryCallback&, PreparedQueryResult)>&& callback)
{
 ASSERT(!_callbacks.empty() || _isPrepared, "Attempted to set callback function for prepared query on a string async query");
 _callbacks.emplace(std::move(callback));
 return std::move(*this);
}
 
void QueryCallback::SetNextQuery(QueryCallback&& next)
{
 MoveFrom(this, std::move(next));
}
 
bool QueryCallback::InvokeIfReady()
{
 QueryCallbackData& callback = _callbacks.front();
 auto checkStateAndReturnCompletion = [this]()
 {
 _callbacks.pop();
 bool hasNext = !_isPrepared ? _string.valid() : _prepared.valid();
 if (_callbacks.empty())
 {
 ASSERT(!hasNext);
 return true;
 }
 
 // abort chain
 if (!hasNext)
 return true;
 
 ASSERT(_isPrepared == _callbacks.front()._isPrepared);
 return false;
 };
 
 if (!_isPrepared)
 {
 if (_string.valid() && _string.wait_for(std::chrono::seconds(0)) == std::future_status::ready)
 {
 QueryResultFuture f(std::move(_string));
 std::function<void(QueryCallback&, QueryResult)> cb(std::move(callback._string));
 cb(*this, f.get());
 return checkStateAndReturnCompletion();
 }
 }
 else
 {
 if (_prepared.valid() && _prepared.wait_for(std::chrono::seconds(0)) == std::future_status::ready)
 {
 PreparedQueryResultFuture f(std::move(_prepared));
 std::function<void(QueryCallback&, PreparedQueryResult)> cb(std::move(callback._prepared));
 cb(*this, f.get());
 return checkStateAndReturnCompletion();
 }
 }
 
 return false;
}