homework-jianmu/source/dnode/vnode/src/meta/metaSnapshot.c

93 lines
2.3 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/>.
*/
#include "meta.h"
struct SMetaSnapshotReader {
SMeta* pMeta;
TBC* pTbc;
int64_t sver;
int64_t ever;
};
int32_t metaSnapshotReaderOpen(SMeta* pMeta, SMetaSnapshotReader** ppReader, int64_t sver, int64_t ever) {
int32_t code = 0;
int32_t c = 0;
SMetaSnapshotReader* pMetaReader = NULL;
pMetaReader = (SMetaSnapshotReader*)taosMemoryCalloc(1, sizeof(*pMetaReader));
if (pMetaReader == NULL) {
code = TSDB_CODE_OUT_OF_MEMORY;
goto _err;
}
pMetaReader->pMeta = pMeta;
pMetaReader->sver = sver;
pMetaReader->ever = ever;
code = tdbTbcOpen(pMeta->pTbDb, &pMetaReader->pTbc, NULL);
if (code) {
goto _err;
}
code = tdbTbcMoveTo(pMetaReader->pTbc, &(STbDbKey){.version = sver, .uid = INT64_MIN}, sizeof(STbDbKey), &c);
if (code) {
goto _err;
}
*ppReader = pMetaReader;
return code;
_err:
*ppReader = NULL;
return code;
}
int32_t metaSnapshotReaderClose(SMetaSnapshotReader* pReader) {
if (pReader) {
tdbTbcClose(pReader->pTbc);
taosMemoryFree(pReader);
}
return 0;
}
int32_t metaSnapshotRead(SMetaSnapshotReader* pReader, void** ppData, uint32_t* nDatap) {
const void* pKey = NULL;
const void* pData = NULL;
int32_t nKey = 0;
int32_t nData = 0;
int32_t code = 0;
for (;;) {
code = tdbTbcGet(pReader->pTbc, &pKey, &nKey, &pData, &nData);
if (code || ((STbDbKey*)pData)->version > pReader->ever) {
return TSDB_CODE_VND_READ_END;
}
if (((STbDbKey*)pData)->version < pReader->sver) {
continue;
}
break;
}
// copy the data
if (vnodeRealloc(ppData, nData) < 0) {
code = TSDB_CODE_OUT_OF_MEMORY;
return code;
}
memcpy(*ppData, pData, nData);
*nDatap = nData;
return code;
}