homework-jianmu/source/libs/tdb/src/inc/tdbPage.h

143 lines
4.7 KiB
C

/*
* Copyright (c) 2019 TAOS Data, Inc. <jhtao@taosdata.com>
*
* This program is free software: you can use, redistribute, and/or modify
* it under the terms of the GNU Affero General Public License, version 3
* or later ("AGPL"), as published by the Free Software Foundation.
*
* 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.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef _TDB_PAGE_H_
#define _TDB_PAGE_H_
#ifdef __cplusplus
extern "C" {
#endif
typedef u8 SCell;
// PAGE APIS implemented
typedef struct {
int szOffset;
int szPageHdr;
int szFreeCell;
// cell number
int (*getCellNum)(SPage *);
void (*setCellNum)(SPage *, int);
// cell content offset
int (*getCellBody)(SPage *);
void (*setCellBody)(SPage *, int);
// first free cell offset (0 means no free cells)
int (*getCellFree)(SPage *);
void (*setCellFree)(SPage *, int);
// total free bytes
int (*getFreeBytes)(SPage *);
void (*setFreeBytes)(SPage *, int);
// cell offset at idx
int (*getCellOffset)(SPage *, int);
void (*setCellOffset)(SPage *, int, int);
// free cell info
void (*getFreeCellInfo)(SCell *pCell, int *szCell, int *nxOffset);
void (*setFreeCellInfo)(SCell *pCell, int szCell, int nxOffset);
} SPageMethods;
// Page footer
typedef struct __attribute__((__packed__)) {
u8 cksm[4];
} SPageFtr;
struct SPage {
pthread_spinlock_t lock;
int pageSize;
u8 *pData;
SPageMethods *pPageMethods;
// Fields below used by pager and am
u8 *pPageHdr;
u8 *pCellIdx;
u8 *pFreeStart;
u8 *pFreeEnd;
SPageFtr *pPageFtr;
int nOverflow;
SCell *apOvfl[4];
int aiOvfl[4];
int kLen; // key length of the page, -1 for unknown
int vLen; // value length of the page, -1 for unknown
int maxLocal;
int minLocal;
int (*xCellSize)(const SPage *, SCell *);
// Fields used by SPCache
TDB_PCACHE_PAGE
};
// For page lock
#define P_LOCK_SUCC 0
#define P_LOCK_BUSY 1
#define P_LOCK_FAIL -1
#define TDB_INIT_PAGE_LOCK(pPage) pthread_spin_init(&((pPage)->lock), 0)
#define TDB_DESTROY_PAGE_LOCK(pPage) pthread_spin_destroy(&((pPage)->lock))
#define TDB_LOCK_PAGE(pPage) pthread_spin_lock(&((pPage)->lock))
#define TDB_UNLOCK_PAGE(pPage) pthread_spin_unlock(&((pPage)->lock))
#define TDB_TRY_LOCK_PAGE(pPage) \
({ \
int ret; \
if (pthread_spin_trylock(&((pPage)->lock)) == 0) { \
ret = P_LOCK_SUCC; \
} else if (errno == EBUSY) { \
ret = P_LOCK_BUSY; \
} else { \
ret = P_LOCK_FAIL; \
} \
ret; \
})
// APIs
#define TDB_PAGE_TOTAL_CELLS(pPage) ((pPage)->nOverflow + (pPage)->pPageMethods->getCellNum(pPage))
#define TDB_PAGE_USABLE_SIZE(pPage) ((u8 *)(pPage)->pPageFtr - (pPage)->pCellIdx)
#define TDB_PAGE_PGNO(pPage) ((pPage)->pgid.pgno)
#define TDB_BYTES_CELL_TAKEN(pPage, pCell) ((*(pPage)->xCellSize)(pPage, pCell) + (pPage)->pPageMethods->szOffset)
#define TDB_PAGE_OFFSET_SIZE(pPage) ((pPage)->pPageMethods->szOffset)
int tdbPageCreate(int pageSize, SPage **ppPage, void *(*xMalloc)(void *, size_t), void *arg);
int tdbPageDestroy(SPage *pPage, void (*xFree)(void *arg, void *ptr), void *arg);
void tdbPageZero(SPage *pPage, u8 szAmHdr, int (*xCellSize)(const SPage *, SCell *));
void tdbPageInit(SPage *pPage, u8 szAmHdr, int (*xCellSize)(const SPage *, SCell *));
int tdbPageInsertCell(SPage *pPage, int idx, SCell *pCell, int szCell, u8 asOvfl);
int tdbPageDropCell(SPage *pPage, int idx);
void tdbPageCopy(SPage *pFromPage, SPage *pToPage);
static inline SCell *tdbPageGetCell(SPage *pPage, int idx) {
SCell *pCell;
int iOvfl;
int lidx;
ASSERT(idx >= 0 && idx < TDB_PAGE_TOTAL_CELLS(pPage));
iOvfl = 0;
for (; iOvfl < pPage->nOverflow; iOvfl++) {
if (pPage->aiOvfl[iOvfl] == idx) {
pCell = pPage->apOvfl[iOvfl];
return pCell;
} else if (pPage->aiOvfl[iOvfl] > idx) {
break;
}
}
lidx = idx - iOvfl;
ASSERT(lidx >= 0 && lidx < pPage->pPageMethods->getCellNum(pPage));
pCell = pPage->pData + pPage->pPageMethods->getCellOffset(pPage, lidx);
return pCell;
}
#ifdef __cplusplus
}
#endif
#endif /*_TDB_PAGE_H_*/