ClickHouse/src/Interpreters/Context_fwd.h
Ivan 495c6e03aa
Replace all Context references with std::weak_ptr (#22297)
* Replace all Context references with std::weak_ptr

* Fix shared context captured by value

* Fix build

* Fix Context with named sessions

* Fix copy context

* Fix gcc build

* Merge with master and fix build

* Fix gcc-9 build
2021-04-11 02:33:54 +03:00

55 lines
1.2 KiB
C++

#pragma once
#include <Common/Exception.h>
#include <map>
#include <memory>
namespace DB
{
namespace ErrorCodes
{
extern const int LOGICAL_ERROR;
}
class Block;
/// Scalar results of subqueries
using Scalars = std::map<String, Block>;
class Context;
/// Most used types have shorter names
/// TODO: in the first part of refactoring all the context pointers are non-const.
using ContextPtr = std::shared_ptr<Context>;
using ContextConstPtr = std::shared_ptr<const Context>;
using ContextWeakPtr = std::weak_ptr<Context>;
using ContextWeakConstPtr = std::weak_ptr<const Context>;
template <class Shared = ContextPtr>
struct WithContextImpl
{
using Weak = typename Shared::weak_type;
using ConstShared = std::shared_ptr<const typename Shared::element_type>;
using ConstWeak = typename ConstShared::weak_type;
WithContextImpl() = default;
explicit WithContextImpl(Weak context_) : context(context_) {}
inline Shared getContext() const
{
auto ptr = context.lock();
if (!ptr) throw Exception("Context has expired", ErrorCodes::LOGICAL_ERROR);
return ptr;
}
protected:
Weak context;
};
using WithContext = WithContextImpl<>;
using WithConstContext = WithContextImpl<ContextConstPtr>;
}