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Add the sqlite3_normalized_sql() API.

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FossilOrigin-Name: 592b66e8058dd03a056a036e2606247c9efdb06d15eebe9bcc455f7f55e30ae6
This commit is contained in:
mistachkin
2018-10-29 17:53:23 +00:00
parent dbe7d37ae8
commit 8bee11a41e
22 changed files with 996 additions and 66 deletions
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288
src/prepare.c
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@@ -709,6 +709,294 @@ static int sqlite3LockAndPrepare(
return rc;
}
#ifdef SQLITE_ENABLE_NORMALIZE
/*
** Checks if the specified token is a table, column, or function name,
** based on the databases associated with the statement being prepared.
** If the function fails, zero is returned and pRc is filled with the
** error code.
*/
static int shouldTreatAsIdentifier(
sqlite3 *db, /* Database handle. */
const char *zToken, /* Pointer to start of token to be checked */
int nToken, /* Length of token to be checked */
int *pRc /* Pointer to error code upon failure */
){
int bFound = 0; /* Non-zero if token is an identifier name. */
int i, j; /* Database and column loop indexes. */
Schema *pSchema; /* Schema for current database. */
Hash *pHash; /* Hash table of tables for current database. */
HashElem *e; /* Hash element for hash table iteration. */
Table *pTab; /* Database table for columns being checked. */
if( sqlite3IsRowidN(zToken, nToken) ){
return 1;
}
if( nToken>0 ){
int hash = SQLITE_FUNC_HASH(sqlite3UpperToLower[(u8)zToken[0]], nToken);
if( sqlite3FunctionSearchN(hash, zToken, nToken) ) return 1;
}
assert( db!=0 );
sqlite3_mutex_enter(db->mutex);
sqlite3BtreeEnterAll(db);
for(i=0; i<db->nDb; i++){
pHash = &db->aFunc;
if( sqlite3HashFindN(pHash, zToken, nToken) ){
bFound = 1;
break;
}
pSchema = db->aDb[i].pSchema;
if( pSchema==0 ) continue;
pHash = &pSchema->tblHash;
if( sqlite3HashFindN(pHash, zToken, nToken) ){
bFound = 1;
break;
}
for(e=sqliteHashFirst(pHash); e; e=sqliteHashNext(e)){
pTab = sqliteHashData(e);
if( pTab==0 ) continue;
pHash = pTab->pColHash;
if( pHash==0 ){
pTab->pColHash = pHash = sqlite3_malloc(sizeof(Hash));
if( pHash ){
sqlite3HashInit(pHash);
for(j=0; j<pTab->nCol; j++){
Column *pCol = &pTab->aCol[j];
sqlite3HashInsert(pHash, pCol->zName, pCol);
}
}else{
*pRc = SQLITE_NOMEM_BKPT;
bFound = 0;
goto done;
}
}
if( pHash && sqlite3HashFindN(pHash, zToken, nToken) ){
bFound = 1;
goto done;
}
}
}
done:
sqlite3BtreeLeaveAll(db);
sqlite3_mutex_leave(db->mutex);
return bFound;
}
/*
** Attempt to estimate the final output buffer size needed for the fully
** normalized version of the specified SQL string. This should take into
** account any potential expansion that could occur (e.g. via IN clauses
** being expanded, etc). This size returned is the total number of bytes
** including the NUL terminator.
*/
static int estimateNormalizedSize(
const char *zSql, /* The original SQL string */
int nSql, /* Length of original SQL string */
u8 prepFlags /* The flags passed to sqlite3_prepare_v3() */
){
int nOut = nSql + 4;
const char *z = zSql;
while( nOut<nSql*5 ){
while( z[0]!=0 && z[0]!='I' && z[0]!='i' ){ z++; }
if( z[0]==0 ) break;
z++;
if( z[0]!='N' && z[0]!='n' ) break;
z++;
while( sqlite3Isspace(z[0]) ){ z++; }
if( z[0]!='(' ) break;
z++;
nOut += 5; /* ?,?,? */
}
return nOut;
}
/*
** Copy the current token into the output buffer while dealing with quoted
** identifiers. By default, all letters will be converted into lowercase.
** If the bUpper flag is set, uppercase will be used. The piOut argument
** will be used to update the target index into the output string.
*/
static void copyNormalizedToken(
const char *zSql, /* The original SQL string */
int iIn, /* Current index into the original SQL string */
int nToken, /* Number of bytes in the current token */
int tokenFlags, /* Flags returned by the tokenizer */
char *zOut, /* The output string */
int *piOut /* Pointer to target index into the output string */
){
int bQuoted = tokenFlags & SQLITE_TOKEN_QUOTED;
int bKeyword = tokenFlags & SQLITE_TOKEN_KEYWORD;
int j = *piOut, k = 0;
for(; k<nToken; k++){
if( bQuoted ){
if( k==0 && iIn>0 ){
zOut[j++] = '"';
continue;
}else if( k==nToken-1 ){
zOut[j++] = '"';
continue;
}
}
if( bKeyword ){
zOut[j++] = sqlite3Toupper(zSql[iIn+k]);
}else{
zOut[j++] = sqlite3Tolower(zSql[iIn+k]);
}
}
*piOut = j;
}
/*
** Perform normalization of the SQL contained in the prepared statement and
** store the result in the zNormSql field. The schema for the associated
** databases are consulted while performing the normalization in order to
** determine if a token appears to be an identifier. All identifiers are
** left intact in the normalized SQL and all literals are replaced with a
** single '?'.
*/
void sqlite3Normalize(
Vdbe *pVdbe, /* VM being reprepared */
const char *zSql, /* The original SQL string */
int nSql, /* Size of the input string in bytes */
u8 prepFlags /* The flags passed to sqlite3_prepare_v3() */
){
sqlite3 *db; /* Database handle. */
char *z; /* The output string */
int nZ; /* Size of the output string in bytes */
int i; /* Next character to read from zSql[] */
int j; /* Next character to fill in on z[] */
int tokenType = 0; /* Type of the next token */
int prevTokenType = 0; /* Type of the previous token, except spaces */
int n; /* Size of the next token */
int nParen = 0; /* Nesting level of parenthesis */
Hash inHash; /* Table of parenthesis levels to output index. */
db = sqlite3VdbeDb(pVdbe);
assert( db!=0 );
assert( pVdbe->zNormSql==0 );
if( zSql==0 ) return;
nZ = estimateNormalizedSize(zSql, nSql, prepFlags);
z = sqlite3DbMallocRawNN(db, nZ);
if( z==0 ) return;
sqlite3HashInit(&inHash);
for(i=j=0; i<nSql && zSql[i]; i+=n){
int flags = 0;
if( tokenType!=TK_SPACE ) prevTokenType = tokenType;
n = sqlite3GetTokenNormalized((unsigned char*)zSql+i, &tokenType, &flags);
switch( tokenType ){
case TK_SPACE: {
break;
}
case TK_ILLEGAL: {
sqlite3DbFree(db, z);
sqlite3HashClear(&inHash);
return;
}
case TK_STRING:
case TK_INTEGER:
case TK_FLOAT:
case TK_VARIABLE:
case TK_BLOB: {
z[j++] = '?';
break;
}
case TK_LP:
case TK_RP: {
if( tokenType==TK_LP ){
nParen++;
if( prevTokenType==TK_IN ){
assert( nParen<nSql );
sqlite3HashInsert(&inHash, zSql+nParen, SQLITE_INT_TO_PTR(j));
}
}else{
int jj;
assert( nParen<nSql );
jj = SQLITE_PTR_TO_INT(sqlite3HashFind(&inHash, zSql+nParen));
if( jj>0 ){
sqlite3HashInsert(&inHash, zSql+nParen, 0);
assert( jj+6<nZ );
memcpy(z+jj+1, "?,?,?", 5);
j = jj+6;
assert( nZ-1-j>=0 );
assert( nZ-1-j<nZ );
memset(z+j, 0, nZ-1-j);
}
nParen--;
}
assert( nParen>=0 );
/* Fall through */
}
case TK_MINUS:
case TK_SEMI:
case TK_PLUS:
case TK_STAR:
case TK_SLASH:
case TK_REM:
case TK_EQ:
case TK_LE:
case TK_NE:
case TK_LSHIFT:
case TK_LT:
case TK_RSHIFT:
case TK_GT:
case TK_GE:
case TK_BITOR:
case TK_CONCAT:
case TK_COMMA:
case TK_BITAND:
case TK_BITNOT:
case TK_DOT:
case TK_IN:
case TK_IS:
case TK_NOT:
case TK_NULL:
case TK_ID: {
if( tokenType==TK_NULL ){
if( prevTokenType==TK_IS || prevTokenType==TK_NOT ){
/* NULL is a keyword in this case, not a literal value */
}else{
/* Here the NULL is a literal value */
z[j++] = '?';
break;
}
}
if( j>0 && sqlite3IsIdChar(z[j-1]) && sqlite3IsIdChar(zSql[i]) ){
z[j++] = ' ';
}
if( tokenType==TK_ID ){
int i2 = i, n2 = n, rc = SQLITE_OK;
if( nParen>0 ){
assert( nParen<nSql );
sqlite3HashInsert(&inHash, zSql+nParen, 0);
}
if( flags&SQLITE_TOKEN_QUOTED ){ i2++; n2-=2; }
if( shouldTreatAsIdentifier(db, zSql+i2, n2, &rc)==0 ){
if( rc!=SQLITE_OK ){
sqlite3DbFree(db, z);
sqlite3HashClear(&inHash);
return;
}
if( sqlite3_keyword_check(zSql+i2, n2)==0 ){
z[j++] = '?';
break;
}
}
}
copyNormalizedToken(zSql, i, n, flags, z, &j);
break;
}
}
}
assert( j<nZ && "one" );
while( j>0 && z[j-1]==' ' ){ j--; }
if( j>0 && z[j-1]!=';' ){ z[j++] = ';'; }
z[j] = 0;
assert( j<nZ && "two" );
pVdbe->zNormSql = z;
sqlite3HashClear(&inHash);
}
#endif /* SQLITE_ENABLE_NORMALIZE */
/*
** Rerun the compilation of a statement after a schema change.
**