greenplumn CTaskLocalStorage 代码
文件路径：/src/backend/gporca/libgpos/include/gpos/task/CTaskLocalStorage.h
/---------------------------------------------------------------------------
/ Greenplum Database
/ Copyright (C) 2009 Greenplum, Inc.
/
/ @filename:
/ CTaskLocalStorage.h
/
/ @doc:
/ Task-local storage facility; implements TLS to store an instance
/ of a subclass of CTaskLocalStorageObject by an enum index;
/ no restrictions as to where the actual data is allocated,
/ e.g. Task's memory pool, global memory etc.
/---------------------------------------------------------------------------
#ifndef GPOS_CTaskLocalStorage_H
#define GPOS_CTaskLocalStorage_H
#include "gpos/base.h"
#include "gpos/common/CSyncHashtable.h"
namespace gpos
{
/ fwd declaration
class CTaskLocalStorageObject;
/---------------------------------------------------------------------------
/ @class:
/ CTaskLocalStorage
/
/ @doc:
/ TLS implementation; single instance of this class per task; initialized
/ and destroyed during task setup/tear down
/
/---------------------------------------------------------------------------
class CTaskLocalStorage
{
public:
CTaskLocalStorage(const CTaskLocalStorage &) = delete;
enum Etlsidx
{
EtlsidxTest, / unittest slot
EtlsidxOptCtxt, / optimizer context
EtlsidxInvalid, / used only for hashtable iteration
EtlsidxSentinel
};
/ ctor
CTaskLocalStorage() = default;
/ dtor
~CTaskLocalStorage();
/ reset
void Reset(CMemoryPool *mp);
/ accessors
void Store(CTaskLocalStorageObject *);
CTaskLocalStorageObject *Get(const Etlsidx);
/ delete object
void Remove(CTaskLocalStorageObject *);
/ equality function -- used for hashtable
static BOOL
Equals(const CTaskLocalStorage::Etlsidx &idx,
const CTaskLocalStorage::Etlsidx &idx_other)
{
return idx == idx_other;
}
/ hash function
static ULONG
HashIdx(const CTaskLocalStorage::Etlsidx &idx)
{
/ keys are unique
return static_cast<ULONG>(idx);
}
/ invalid Etlsidx
static const Etlsidx m_invalid_idx;
private:
/ hash table
CSyncHashtable<CTaskLocalStorageObject, Etlsidx> m_hash_table;
}; / class CTaskLocalStorage
} / namespace gpos
#endif / !GPOS_CTaskLocalStorage_H
/ EOF
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