ClickHouse/src/Storages/System/StorageSystemContributors.h
Robert Schulze 330212e0f4
Remove inherited create() method + disallow copying
The original motivation for this commit was that shared_ptr_helper used
std::shared_ptr<>() which does two heap allocations instead of
make_shared<>() which does a single allocation. Turned out that
1. the affected code (--> Storages/) is not on a hot path (rendering the
performance argument moot ...)
2. yet copying Storage objects is potentially dangerous and was
   previously allowed.

Hence, this change

- removes shared_ptr_helper and as a result all inherited create() methods,

- instead, Storage objects are now created using make_shared<>() by the
  caller (for that to work, many constructors had to be made public), and

- all Storage classes were marked as noncopyable using boost::noncopyable.

In sum, we are (likely) not making things faster but the code becomes
cleaner and harder to misuse.
2022-05-02 08:46:52 +02:00

29 lines
669 B
C++

#pragma once
#include <boost/noncopyable.hpp>
#include <Storages/System/IStorageSystemOneBlock.h>
namespace DB
{
class Context;
/** System table "contributors" with list of clickhouse contributors
*/
class StorageSystemContributors final : public IStorageSystemOneBlock<StorageSystemContributors>, boost::noncopyable
{
protected:
void fillData(MutableColumns & res_columns, ContextPtr context, const SelectQueryInfo & query_info) const override;
using IStorageSystemOneBlock::IStorageSystemOneBlock;
public:
std::string getName() const override
{
return "SystemContributors";
}
static NamesAndTypesList getNamesAndTypes();
};
}