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Simplify the sessions preupdate-hook logic for transforming NULL to X'' for

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column sqlite_stat1.idx.

FossilOrigin-Name: 089d7cecaaa47db58320b216a111a5e56123d022008be6c81bc0746148bbdb58
This commit is contained in:
dan
2018-01-18 15:06:23 +00:00
parent 3739f29807
commit 1611e5a301
3 changed files with 103 additions and 57 deletions
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143
ext/session/sqlite3session.c
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@ -46,6 +46,7 @@ struct sqlite3_session {
int rc; /* Non-zero if an error has occurred */
void *pFilterCtx; /* First argument to pass to xTableFilter */
int (*xTableFilter)(void *pCtx, const char *zTab);
sqlite3_value *pZeroBlob; /* Value containing X'' */
sqlite3_session *pNext; /* Next session object on same db. */
SessionTable *pTable; /* List of attached tables */
SessionHook hook; /* APIs to grab new and old data with */
@ -473,35 +474,32 @@ static int sessionPreupdateHash(
if( rc!=SQLITE_OK ) return rc;
eType = sqlite3_value_type(pVal);
if( pTab->bStat1 && eType==SQLITE_NULL ){
h = sessionHashAppendType(h, SQLITE_BLOB);
}else{
h = sessionHashAppendType(h, eType);
if( eType==SQLITE_INTEGER || eType==SQLITE_FLOAT ){
i64 iVal;
if( eType==SQLITE_INTEGER ){
iVal = sqlite3_value_int64(pVal);
}else{
double rVal = sqlite3_value_double(pVal);
assert( sizeof(iVal)==8 && sizeof(rVal)==8 );
memcpy(&iVal, &rVal, 8);
}
h = sessionHashAppendI64(h, iVal);
}else if( eType==SQLITE_TEXT || eType==SQLITE_BLOB ){
const u8 *z;
int n;
if( eType==SQLITE_TEXT ){
z = (const u8 *)sqlite3_value_text(pVal);
}else{
z = (const u8 *)sqlite3_value_blob(pVal);
}
n = sqlite3_value_bytes(pVal);
if( !z && (eType!=SQLITE_BLOB || n>0) ) return SQLITE_NOMEM;
h = sessionHashAppendBlob(h, n, z);
h = sessionHashAppendType(h, eType);
if( eType==SQLITE_INTEGER || eType==SQLITE_FLOAT ){
i64 iVal;
if( eType==SQLITE_INTEGER ){
iVal = sqlite3_value_int64(pVal);
}else{
assert( eType==SQLITE_NULL );
*pbNullPK = 1;
double rVal = sqlite3_value_double(pVal);
assert( sizeof(iVal)==8 && sizeof(rVal)==8 );
memcpy(&iVal, &rVal, 8);
}
h = sessionHashAppendI64(h, iVal);
}else if( eType==SQLITE_TEXT || eType==SQLITE_BLOB ){
const u8 *z;
int n;
if( eType==SQLITE_TEXT ){
z = (const u8 *)sqlite3_value_text(pVal);
}else{
z = (const u8 *)sqlite3_value_blob(pVal);
}
n = sqlite3_value_bytes(pVal);
if( !z && (eType!=SQLITE_BLOB || n>0) ) return SQLITE_NOMEM;
h = sessionHashAppendBlob(h, n, z);
}else{
assert( eType==SQLITE_NULL );
assert( pTab->bStat1==0 || i!=1 );
*pbNullPK = 1;
}
}
}
@ -555,7 +553,7 @@ static unsigned int sessionChangeHash(
|| eType==SQLITE_TEXT || eType==SQLITE_BLOB
|| eType==SQLITE_NULL || eType==0
);
assert( !isPK || (eType!=0 && (pTab->bStat1 || eType!=SQLITE_NULL)) );
assert( !isPK || (eType!=0 && eType!=SQLITE_NULL) );
if( isPK ){
a++;
@ -563,7 +561,7 @@ static unsigned int sessionChangeHash(
if( eType==SQLITE_INTEGER || eType==SQLITE_FLOAT ){
h = sessionHashAppendI64(h, sessionGetI64(a));
a += 8;
}else if( eType!=SQLITE_NULL ){
}else{
int n;
a += sessionVarintGet(a, &n);
h = sessionHashAppendBlob(h, n, a);
@ -799,7 +797,6 @@ static int sessionPreupdateEqual(
sqlite3_value *pVal; /* Value returned by preupdate_new/old */
int rc; /* Error code from preupdate_new/old */
int eType = *a++; /* Type of value from change record */
int eValType;
/* The following calls to preupdate_new() and preupdate_old() can not
** fail. This is because they cache their return values, and by the
@ -814,14 +811,7 @@ static int sessionPreupdateEqual(
rc = pSession->hook.xOld(pSession->hook.pCtx, iCol, &pVal);
}
assert( rc==SQLITE_OK );
eValType = sqlite3_value_type(pVal);
if( eType==SQLITE_BLOB && eValType==SQLITE_NULL && pTab->bStat1 ){
int n;
a += sessionVarintGet(a, &n);
if( n!=0 ) return 0;
continue;
}
if( eValType!=eType ) return 0;
if( sqlite3_value_type(pVal)!=eType ) return 0;
/* A SessionChange object never has a NULL value in a PK column */
assert( eType==SQLITE_INTEGER || eType==SQLITE_FLOAT
@ -1068,6 +1058,47 @@ static int sessionInitTable(sqlite3_session *pSession, SessionTable *pTab){
return (pSession->rc || pTab->abPK==0);
}
/*
** Versions of the four methods in object SessionHook for use with the
** sqlite_stat1 table. The purpose of this is to substitute a zero-length
** blob each time a NULL value is read from the "idx" column of the
** sqlite_stat1 table.
*/
typedef struct SessionStat1Ctx SessionStat1Ctx;
struct SessionStat1Ctx {
SessionHook hook;
sqlite3_session *pSession;
};
static int sessionStat1Old(void *pCtx, int iCol, sqlite3_value **ppVal){
SessionStat1Ctx *p = (SessionStat1Ctx*)pCtx;
sqlite3_value *pVal = 0;
int rc = p->hook.xOld(p->hook.pCtx, iCol, &pVal);
if( rc==SQLITE_OK && iCol==1 && sqlite3_value_type(pVal)==SQLITE_NULL ){
pVal = p->pSession->pZeroBlob;
}
*ppVal = pVal;
return rc;
}
static int sessionStat1New(void *pCtx, int iCol, sqlite3_value **ppVal){
SessionStat1Ctx *p = (SessionStat1Ctx*)pCtx;
sqlite3_value *pVal = 0;
int rc = p->hook.xNew(p->hook.pCtx, iCol, &pVal);
if( rc==SQLITE_OK && iCol==1 && sqlite3_value_type(pVal)==SQLITE_NULL ){
pVal = p->pSession->pZeroBlob;
}
*ppVal = pVal;
return rc;
}
static int sessionStat1Count(void *pCtx){
SessionStat1Ctx *p = (SessionStat1Ctx*)pCtx;
return p->hook.xCount(p->hook.pCtx);
}
static int sessionStat1Depth(void *pCtx){
SessionStat1Ctx *p = (SessionStat1Ctx*)pCtx;
return p->hook.xDepth(p->hook.pCtx);
}
/*
** This function is only called from with a pre-update-hook reporting a
** change on table pTab (attached to session pSession). The type of change
@ -1084,6 +1115,7 @@ static void sessionPreupdateOneChange(
int iHash;
int bNull = 0;
int rc = SQLITE_OK;
SessionStat1Ctx stat1;
if( pSession->rc ) return;
@ -1103,13 +1135,32 @@ static void sessionPreupdateOneChange(
return;
}
if( pTab->bStat1 ){
stat1.hook = pSession->hook;
stat1.pSession = pSession;
pSession->hook.pCtx = (void*)&stat1;
pSession->hook.xNew = sessionStat1New;
pSession->hook.xOld = sessionStat1Old;
pSession->hook.xCount = sessionStat1Count;
pSession->hook.xDepth = sessionStat1Depth;
if( pSession->pZeroBlob==0 ){
sqlite3_value *p = sqlite3ValueNew(0);
if( p==0 ){
rc = SQLITE_NOMEM;
goto error_out;
}
sqlite3ValueSetStr(p, 0, "", 0, SQLITE_STATIC);
pSession->pZeroBlob = p;
}
}
/* Calculate the hash-key for this change. If the primary key of the row
** includes a NULL value, exit early. Such changes are ignored by the
** session module. */
rc = sessionPreupdateHash(pSession, pTab, op==SQLITE_INSERT, &iHash, &bNull);
if( rc!=SQLITE_OK ) goto error_out;
if( bNull==0 || pTab->bStat1 ){
if( bNull==0 ){
/* Search the hash table for an existing record for this row. */
SessionChange *pC;
for(pC=pTab->apChange[iHash]; pC; pC=pC->pNext){
@ -1144,7 +1195,6 @@ static void sessionPreupdateOneChange(
rc = sessionSerializeValue(0, p, &nByte);
if( rc!=SQLITE_OK ) goto error_out;
}
if( pTab->bStat1 ) nByte += 30;
/* Allocate the change object */
pChange = (SessionChange *)sqlite3_malloc(nByte);
@ -1168,12 +1218,7 @@ static void sessionPreupdateOneChange(
}else if( pTab->abPK[i] ){
pSession->hook.xNew(pSession->hook.pCtx, i, &p);
}
if( p && pTab->bStat1 && sqlite3_value_type(p)==SQLITE_NULL ){
pChange->aRecord[nByte++] = SQLITE_BLOB;
nByte += sessionVarintPut(&pChange->aRecord[nByte], 0);
}else{
sessionSerializeValue(&pChange->aRecord[nByte], p, &nByte);
}
sessionSerializeValue(&pChange->aRecord[nByte], p, &nByte);
}
/* Add the change to the hash-table */
@ -1198,6 +1243,9 @@ static void sessionPreupdateOneChange(
/* If an error has occurred, mark the session object as failed. */
error_out:
if( pTab->bStat1 ){
pSession->hook = stat1.hook;
}
if( rc!=SQLITE_OK ){
pSession->rc = rc;
}
@ -1659,6 +1707,7 @@ void sqlite3session_delete(sqlite3_session *pSession){
}
}
sqlite3_mutex_leave(sqlite3_db_mutex(db));
sqlite3ValueFree(pSession->pZeroBlob);
/* Delete all attached table objects. And the contents of their
** associated hash-tables. */
@ -2188,7 +2237,7 @@ static int sessionSelectBind(
switch( eType ){
case 0:
case SQLITE_NULL:
/* assert( abPK[i]==0 ); */
assert( abPK[i]==0 );
break;
case SQLITE_INTEGER: {