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Simplifications to the memjournal.c logic to facilitate testing.

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FossilOrigin-Name: 8baa2c2c7698e03418531482a8314a5d7ae2c7d3
This commit is contained in:
drh
2016-03-09 04:17:17 +00:00
parent 769b4c95ca
commit d93b2b840d
3 changed files with 43 additions and 42 deletions
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71
src/memjournal.c
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@@ -82,38 +82,41 @@ static int memjrnlRead(
sqlite_int64 iOfst /* Begin reading at this offset */
){
MemJournal *p = (MemJournal *)pJfd;
u8 *zOut = zBuf;
int nRead = iAmt;
int iChunkOffset;
FileChunk *pChunk;
#ifdef SQLITE_ENABLE_ATOMIC_WRITE
if( (iAmt+iOfst)>p->endpoint.iOffset ){
return SQLITE_IOERR_SHORT_READ;
}else{
u8 *zOut = zBuf;
int nRead = iAmt;
int iChunkOffset;
FileChunk *pChunk;
if( p->readpoint.iOffset!=iOfst || iOfst==0 ){
sqlite3_int64 iOff = 0;
for(pChunk=p->pFirst;
ALWAYS(pChunk) && (iOff+p->nChunkSize)<=iOfst;
pChunk=pChunk->pNext
){
iOff += p->nChunkSize;
}
}else{
pChunk = p->readpoint.pChunk;
}
iChunkOffset = (int)(iOfst%p->nChunkSize);
do {
int iSpace = p->nChunkSize - iChunkOffset;
int nCopy = MIN(nRead, (p->nChunkSize - iChunkOffset));
memcpy(zOut, (u8*)pChunk->zChunk + iChunkOffset, nCopy);
zOut += nCopy;
nRead -= iSpace;
iChunkOffset = 0;
} while( nRead>=0 && (pChunk=pChunk->pNext)!=0 && nRead>0 );
p->readpoint.iOffset = iOfst+iAmt;
p->readpoint.pChunk = pChunk;
}
#endif
assert( (iAmt+iOfst)<=p->endpoint.iOffset );
if( p->readpoint.iOffset!=iOfst || iOfst==0 ){
sqlite3_int64 iOff = 0;
for(pChunk=p->pFirst;
ALWAYS(pChunk) && (iOff+p->nChunkSize)<=iOfst;
pChunk=pChunk->pNext
){
iOff += p->nChunkSize;
}
}else{
pChunk = p->readpoint.pChunk;
}
iChunkOffset = (int)(iOfst%p->nChunkSize);
do {
int iSpace = p->nChunkSize - iChunkOffset;
int nCopy = MIN(nRead, (p->nChunkSize - iChunkOffset));
memcpy(zOut, (u8*)pChunk->zChunk + iChunkOffset, nCopy);
zOut += nCopy;
nRead -= iSpace;
iChunkOffset = 0;
} while( nRead>=0 && (pChunk=pChunk->pNext)!=0 && nRead>0 );
p->readpoint.iOffset = iOfst+iAmt;
p->readpoint.pChunk = pChunk;
return SQLITE_OK;
}
@@ -146,14 +149,12 @@ static int memjrnlCreateFile(MemJournal *p){
i64 iOff = 0;
FileChunk *pIter;
for(pIter=copy.pFirst; pIter; pIter=pIter->pNext){
int nWrite = nChunk;
if( pIter==copy.endpoint.pChunk ){
nWrite = copy.endpoint.iOffset % copy.nChunkSize;
if( nWrite==0 ) nWrite = copy.nChunkSize;
if( iOff + nChunk > copy.endpoint.iOffset ){
nChunk = copy.endpoint.iOffset - iOff;
}
rc = sqlite3OsWrite(pReal, (u8*)pIter->zChunk, nWrite, iOff);
rc = sqlite3OsWrite(pReal, (u8*)pIter->zChunk, nChunk, iOff);
if( rc ) break;
iOff += nWrite;
iOff += nChunk;
}
if( rc==SQLITE_OK ){
/* No error has occurred. Free the in-memory buffers. */