static int echoTransactionCall(sqlite3_vtab *tab, const char *zCall){
char *z;
echo_vtab *pVtab = (echo_vtab *)tab;
z = sqlite3_mprintf("echo(%s)", pVtab->zTableName);
if( z==0 ) return SQLITE_NOMEM;
appendToEchoModule(pVtab->interp, zCall);
appendToEchoModule(pVtab->interp, z);
sqlite3_free(z);
return SQLITE_OK;
}
static int echoCreate(
sqlite3 *db,
void *pAux,
int argc, const char *const*argv,
sqlite3_vtab **ppVtab,
char **pzErr
){
int rc = SQLITE_OK;
appendToEchoModule(((EchoModule *)pAux)->interp, "xCreate");
rc = echoConstructor(db, pAux, argc, argv, ppVtab, pzErr);
if( rc==SQLITE_OK && argc==5 ){
char *zSql;
echo_vtab *pVtab = *(echo_vtab **)ppVtab;
pVtab->zLogName = sqlite3_mprintf("%s", argv[4]);
zSql = sqlite3_mprintf("CREATE TABLE %Q(logmsg)", pVtab->zLogName);
rc = sqlite3_exec(db, zSql, 0, 0, 0);
sqlite3_free(zSql);
if( rc!=SQLITE_OK ){
*pzErr = sqlite3_mprintf("%s", sqlite3_errmsg(db));
}
}
if( *ppVtab && rc!=SQLITE_OK ){
echoDestructor(*ppVtab);
*ppVtab = 0;
}
if( rc==SQLITE_OK ){
(*(echo_vtab**)ppVtab)->inTransaction = 1;
}
return rc;
}
/*
** Echo virtual table module xFilter method.
*/
static int echoFilter(
sqlite3_vtab_cursor *pVtabCursor,
int idxNum, const char *idxStr,
int argc, sqlite3_value **argv
){
int rc;
int i;
echo_cursor *pCur = (echo_cursor *)pVtabCursor;
echo_vtab *pVtab = (echo_vtab *)pVtabCursor->pVtab;
sqlite3 *db = pVtab->db;
if( simulateVtabError(pVtab, "xFilter") ){
return SQLITE_ERROR;
}
/* Check that idxNum matches idxStr */
assert( idxNum==hashString(idxStr) );
/* Log arguments to the ::echo_module Tcl variable */
appendToEchoModule(pVtab->interp, "xFilter");
appendToEchoModule(pVtab->interp, idxStr);
for(i=0; i<argc; i++){
appendToEchoModule(pVtab->interp, (const char*)sqlite3_value_text(argv[i]));
}
sqlite3_finalize(pCur->pStmt);
pCur->pStmt = 0;
/* Prepare the SQL statement created by echoBestIndex and bind the
** runtime parameters passed to this function to it.
*/
rc = sqlite3_prepare(db, idxStr, -1, &pCur->pStmt, 0);
assert( pCur->pStmt || rc!=SQLITE_OK );
for(i=0; rc==SQLITE_OK && i<argc; i++){
rc = sqlite3_bind_value(pCur->pStmt, i+1, argv[i]);
}
/* If everything was successful, advance to the first row of the scan */
if( rc==SQLITE_OK ){
rc = echoNext(pVtabCursor);
}
return rc;
}
static int echoConstructor(
sqlite3 *db,
void *pAux,
int argc, const char *const*argv,
sqlite3_vtab **ppVtab,
char **pzErr
){
int rc;
int i;
echo_vtab *pVtab;
pVtab = sqlite3MallocZero( sizeof(*pVtab) );
if( !pVtab ){
return SQLITE_NOMEM;
}
pVtab->interp = ((EchoModule *)pAux)->interp;
pVtab->db = db;
pVtab->zThis = sqlite3_mprintf("%s", argv[2]);
if( !pVtab->zThis ){
echoDestructor((sqlite3_vtab *)pVtab);
return SQLITE_NOMEM;
}
if( argc>3 ){
pVtab->zTableName = sqlite3_mprintf("%s", argv[3]);
dequoteString(pVtab->zTableName);
if( pVtab->zTableName && pVtab->zTableName[0]=='*' ){
char *z = sqlite3_mprintf("%s%s", argv[2], &(pVtab->zTableName[1]));
sqlite3_free(pVtab->zTableName);
pVtab->zTableName = z;
pVtab->isPattern = 1;
}
if( !pVtab->zTableName ){
echoDestructor((sqlite3_vtab *)pVtab);
return SQLITE_NOMEM;
}
}
for(i=0; i<argc; i++){
appendToEchoModule(pVtab->interp, argv[i]);
}
rc = echoDeclareVtab(pVtab, db);
if( rc!=SQLITE_OK ){
echoDestructor((sqlite3_vtab *)pVtab);
return rc;
}
*ppVtab = &pVtab->base;
return SQLITE_OK;
}
static int echoConnect(
sqlite3 *db,
void *pAux,
int argc, const char *const*argv,
sqlite3_vtab **ppVtab,
char **pzErr
){
appendToEchoModule(((EchoModule *)pAux)->interp, "xConnect");
return echoConstructor(db, pAux, argc, argv, ppVtab, pzErr);
}
static int echoFilter(
sqlite3_vtab_cursor *pVtabCursor,
int idxNum, const char *idxStr,
int argc, sqlite3_value **argv
){
int rc;
int i;
echo_cursor *pCur = (echo_cursor *)pVtabCursor;
echo_vtab *pVtab = (echo_vtab *)pVtabCursor->pVtab;
sqlite3 *db = pVtab->db;
if( simulateVtabError(pVtab, "xFilter") ){
return SQLITE_ERROR;
}
assert( idxNum==hashString(idxStr) );
appendToEchoModule(pVtab->interp, "xFilter");
appendToEchoModule(pVtab->interp, idxStr);
for(i=0; i<argc; i++){
appendToEchoModule(pVtab->interp, (const char*)sqlite3_value_text(argv[i]));
}
sqlite3_finalize(pCur->pStmt);
pCur->pStmt = 0;
rc = sqlite3_prepare(db, idxStr, -1, &pCur->pStmt, 0);
assert( pCur->pStmt || rc!=SQLITE_OK );
for(i=0; rc==SQLITE_OK && i<argc; i++){
rc = sqlite3_bind_value(pCur->pStmt, i+1, argv[i]);
}
if( rc==SQLITE_OK ){
rc = echoNext(pVtabCursor);
}
return rc;
}
static int echoDestroy(sqlite3_vtab *pVtab){
int rc = SQLITE_OK;
echo_vtab *p = (echo_vtab *)pVtab;
appendToEchoModule(((echo_vtab *)pVtab)->interp, "xDestroy");
if( p && p->zLogName ){
char *zSql;
zSql = sqlite3_mprintf("DROP TABLE %Q", p->zLogName);
rc = sqlite3_exec(p->db, zSql, 0, 0, 0);
sqlite3_free(zSql);
}
if( rc==SQLITE_OK ){
rc = echoDestructor(pVtab);
}
return rc;
}
/*
** Echo virtual table module xDestroy method.
*/
static int echoDestroy(sqlite3_vtab *pVtab){
int rc = SQLITE_OK;
echo_vtab *p = (echo_vtab *)pVtab;
appendToEchoModule(((echo_vtab *)pVtab)->interp, "xDestroy");
/* Drop the "log" table, if one exists (see echoCreate() for details) */
if( p && p->zLogName ){
char *zSql;
zSql = sqlite3_mprintf("DROP TABLE %Q", p->zLogName);
rc = sqlite3_exec(p->db, zSql, 0, 0, 0);
sqlite3_free(zSql);
}
if( rc==SQLITE_OK ){
rc = echoDestructor(pVtab);
}
return rc;
}
/*
** Echo virtual table module xCreate method.
*/
static int echoCreate(
sqlite3 *db,
void *pAux,
int argc, const char *const*argv,
sqlite3_vtab **ppVtab,
char **pzErr
){
int rc = SQLITE_OK;
appendToEchoModule(((EchoModule *)pAux)->interp, "xCreate");
rc = echoConstructor(db, pAux, argc, argv, ppVtab, pzErr);
/* If there were two arguments passed to the module at the SQL level
** (i.e. "CREATE VIRTUAL TABLE tbl USING echo(arg1, arg2)"), then
** the second argument is used as a table name. Attempt to create
** such a table with a single column, "logmsg". This table will
** be used to log calls to the xUpdate method. It will be deleted
** when the virtual table is DROPed.
**
** Note: The main point of this is to test that we can drop tables
** from within an xDestroy method call.
*/
if( rc==SQLITE_OK && argc==5 ){
char *zSql;
echo_vtab *pVtab = *(echo_vtab **)ppVtab;
pVtab->zLogName = sqlite3_mprintf("%s", argv[4]);
zSql = sqlite3_mprintf("CREATE TABLE %Q(logmsg)", pVtab->zLogName);
rc = sqlite3_exec(db, zSql, 0, 0, 0);
sqlite3_free(zSql);
if( rc!=SQLITE_OK ){
*pzErr = sqlite3_mprintf("%s", sqlite3_errmsg(db));
}
}
if( *ppVtab && rc!=SQLITE_OK ){
echoDestructor(*ppVtab);
*ppVtab = 0;
}
if( rc==SQLITE_OK ){
(*(echo_vtab**)ppVtab)->inTransaction = 1;
}
return rc;
}
static int echoBestIndex(sqlite3_vtab *tab, sqlite3_index_info *pIdxInfo){
int ii;
char *zQuery = 0;
char *zNew;
int nArg = 0;
const char *zSep = "WHERE";
echo_vtab *pVtab = (echo_vtab *)tab;
sqlite3_stmt *pStmt = 0;
Tcl_Interp *interp = pVtab->interp;
int nRow;
int useIdx = 0;
int rc = SQLITE_OK;
int useCost = 0;
double cost;
int isIgnoreUsable = 0;
if( Tcl_GetVar(interp, "echo_module_ignore_usable", TCL_GLOBAL_ONLY) ){
isIgnoreUsable = 1;
}
if( simulateVtabError(pVtab, "xBestIndex") ){
return SQLITE_ERROR;
}
if( Tcl_GetVar(interp, "echo_module_cost", TCL_GLOBAL_ONLY) ){
cost = atof(Tcl_GetVar(interp, "echo_module_cost", TCL_GLOBAL_ONLY));
useCost = 1;
} else {
zQuery = sqlite3_mprintf("SELECT count(*) FROM %Q", pVtab->zTableName);
if( !zQuery ){
return SQLITE_NOMEM;
}
rc = sqlite3_prepare(pVtab->db, zQuery, -1, &pStmt, 0);
sqlite3_free(zQuery);
if( rc!=SQLITE_OK ){
return rc;
}
sqlite3_step(pStmt);
nRow = sqlite3_column_int(pStmt, 0);
rc = sqlite3_finalize(pStmt);
if( rc!=SQLITE_OK ){
return rc;
}
}
zQuery = sqlite3_mprintf("SELECT rowid, * FROM %Q", pVtab->zTableName);
if( !zQuery ){
return SQLITE_NOMEM;
}
for(ii=0; ii<pIdxInfo->nConstraint; ii++){
const struct sqlite3_index_constraint *pConstraint;
struct sqlite3_index_constraint_usage *pUsage;
int iCol;
pConstraint = &pIdxInfo->aConstraint[ii];
pUsage = &pIdxInfo->aConstraintUsage[ii];
if( !isIgnoreUsable && !pConstraint->usable ) continue;
iCol = pConstraint->iColumn;
if( pVtab->aIndex[iCol] || iCol<0 ){
char *zCol = pVtab->aCol[iCol];
char *zOp = 0;
useIdx = 1;
if( iCol<0 ){
zCol = "rowid";
}
switch( pConstraint->op ){
case SQLITE_INDEX_CONSTRAINT_EQ:
zOp = "="; break;
case SQLITE_INDEX_CONSTRAINT_LT:
zOp = "<"; break;
case SQLITE_INDEX_CONSTRAINT_GT:
zOp = ">"; break;
case SQLITE_INDEX_CONSTRAINT_LE:
zOp = "<="; break;
case SQLITE_INDEX_CONSTRAINT_GE:
zOp = ">="; break;
case SQLITE_INDEX_CONSTRAINT_MATCH:
zOp = "LIKE"; break;
}
if( zOp[0]=='L' ){
zNew = sqlite3_mprintf(" %s %s LIKE (SELECT '%%'||?||'%%')",
zSep, zCol);
} else {
zNew = sqlite3_mprintf(" %s %s %s ?", zSep, zCol, zOp);
}
string_concat(&zQuery, zNew, 1, &rc);
zSep = "AND";
pUsage->argvIndex = ++nArg;
pUsage->omit = 1;
}
}
if( pIdxInfo->nOrderBy==1 && pVtab->aIndex[pIdxInfo->aOrderBy->iColumn] ){
int iCol = pIdxInfo->aOrderBy->iColumn;
char *zCol = pVtab->aCol[iCol];
char *zDir = pIdxInfo->aOrderBy->desc?"DESC":"ASC";
if( iCol<0 ){
zCol = "rowid";
}
zNew = sqlite3_mprintf(" ORDER BY %s %s", zCol, zDir);
string_concat(&zQuery, zNew, 1, &rc);
pIdxInfo->orderByConsumed = 1;
}
appendToEchoModule(pVtab->interp, "xBestIndex");;
appendToEchoModule(pVtab->interp, zQuery);
if( !zQuery ){
return rc;
}
pIdxInfo->idxNum = hashString(zQuery);
pIdxInfo->idxStr = zQuery;
pIdxInfo->needToFreeIdxStr = 1;
if( useCost ){
pIdxInfo->estimatedCost = cost;
}else if( useIdx ){
for( ii=0; ii<(sizeof(int)*8); ii++ ){
if( nRow & (1<<ii) ){
pIdxInfo->estimatedCost = (double)ii;
}
}
}else{
pIdxInfo->estimatedCost = (double)nRow;
}
return rc;
}
static int echoDisconnect(sqlite3_vtab *pVtab){
appendToEchoModule(((echo_vtab *)pVtab)->interp, "xDisconnect");
return echoDestructor(pVtab);
}
/*
** The echo module implements the subset of query constraints and sort
** orders that may take advantage of SQLite indices on the underlying
** real table. For example, if the real table is declared as:
**
** CREATE TABLE real(a, b, c);
** CREATE INDEX real_index ON real(b);
**
** then the echo module handles WHERE or ORDER BY clauses that refer
** to the column "b", but not "a" or "c". If a multi-column index is
** present, only its left most column is considered.
**
** This xBestIndex method encodes the proposed search strategy as
** an SQL query on the real table underlying the virtual echo module
** table and stores the query in sqlite3_index_info.idxStr. The SQL
** statement is of the form:
**
** SELECT rowid, * FROM <real-table> ?<where-clause>? ?<order-by-clause>?
**
** where the <where-clause> and <order-by-clause> are determined
** by the contents of the structure pointed to by the pIdxInfo argument.
*/
static int echoBestIndex(sqlite3_vtab *tab, sqlite3_index_info *pIdxInfo){
int ii;
char *zQuery = 0;
char *zCol = 0;
char *zNew;
int nArg = 0;
const char *zSep = "WHERE";
echo_vtab *pVtab = (echo_vtab *)tab;
sqlite3_stmt *pStmt = 0;
Tcl_Interp *interp = pVtab->interp;
int nRow = 0;
int useIdx = 0;
int rc = SQLITE_OK;
int useCost = 0;
double cost = 0;
int isIgnoreUsable = 0;
if( Tcl_GetVar(interp, "echo_module_ignore_usable", TCL_GLOBAL_ONLY) ){
isIgnoreUsable = 1;
}
if( simulateVtabError(pVtab, "xBestIndex") ){
return SQLITE_ERROR;
}
/* Determine the number of rows in the table and store this value in local
** variable nRow. The 'estimated-cost' of the scan will be the number of
** rows in the table for a linear scan, or the log (base 2) of the
** number of rows if the proposed scan uses an index.
*/
if( Tcl_GetVar(interp, "echo_module_cost", TCL_GLOBAL_ONLY) ){
cost = atof(Tcl_GetVar(interp, "echo_module_cost", TCL_GLOBAL_ONLY));
useCost = 1;
} else {
zQuery = sqlite3_mprintf("SELECT count(*) FROM %Q", pVtab->zTableName);
if( !zQuery ){
return SQLITE_NOMEM;
}
rc = sqlite3_prepare(pVtab->db, zQuery, -1, &pStmt, 0);
sqlite3_free(zQuery);
if( rc!=SQLITE_OK ){
return rc;
}
sqlite3_step(pStmt);
nRow = sqlite3_column_int(pStmt, 0);
rc = sqlite3_finalize(pStmt);
if( rc!=SQLITE_OK ){
return rc;
}
}
zCol = echoSelectList(pVtab, pIdxInfo);
if( !zCol ) return SQLITE_NOMEM;
zQuery = sqlite3_mprintf("SELECT rowid%z FROM %Q", zCol, pVtab->zTableName);
if( !zQuery ) return SQLITE_NOMEM;
for(ii=0; ii<pIdxInfo->nConstraint; ii++){
const struct sqlite3_index_constraint *pConstraint;
struct sqlite3_index_constraint_usage *pUsage;
int iCol;
pConstraint = &pIdxInfo->aConstraint[ii];
pUsage = &pIdxInfo->aConstraintUsage[ii];
if( !isIgnoreUsable && !pConstraint->usable ) continue;
iCol = pConstraint->iColumn;
if( iCol<0 || pVtab->aIndex[iCol] ){
char *zCol = iCol>=0 ? pVtab->aCol[iCol] : "rowid";
char *zOp = 0;
useIdx = 1;
switch( pConstraint->op ){
case SQLITE_INDEX_CONSTRAINT_EQ:
zOp = "="; break;
case SQLITE_INDEX_CONSTRAINT_LT:
zOp = "<"; break;
case SQLITE_INDEX_CONSTRAINT_GT:
zOp = ">"; break;
case SQLITE_INDEX_CONSTRAINT_LE:
zOp = "<="; break;
case SQLITE_INDEX_CONSTRAINT_GE:
zOp = ">="; break;
case SQLITE_INDEX_CONSTRAINT_MATCH:
/* Purposely translate the MATCH operator into a LIKE, which
** will be used by the next block of code to construct a new
** query. It should also be noted here that the next block
** of code requires the first letter of this operator to be
** in upper-case to trigger the special MATCH handling (i.e.
** wrapping the bound parameter with literal '%'s).
*/
zOp = "LIKE"; break;
case SQLITE_INDEX_CONSTRAINT_LIKE:
zOp = "like"; break;
case SQLITE_INDEX_CONSTRAINT_GLOB:
zOp = "glob"; break;
case SQLITE_INDEX_CONSTRAINT_REGEXP:
zOp = "regexp"; break;
}
if( zOp[0]=='L' ){
zNew = sqlite3_mprintf(" %s %s LIKE (SELECT '%%'||?||'%%')",
zSep, zCol);
} else {
zNew = sqlite3_mprintf(" %s %s %s ?", zSep, zCol, zOp);
}
string_concat(&zQuery, zNew, 1, &rc);
zSep = "AND";
pUsage->argvIndex = ++nArg;
pUsage->omit = 1;
}
}
/* If there is only one term in the ORDER BY clause, and it is
** on a column that this virtual table has an index for, then consume
** the ORDER BY clause.
*/
if( pIdxInfo->nOrderBy==1 && (
pIdxInfo->aOrderBy->iColumn<0 ||
pVtab->aIndex[pIdxInfo->aOrderBy->iColumn]) ){
int iCol = pIdxInfo->aOrderBy->iColumn;
char *zCol = iCol>=0 ? pVtab->aCol[iCol] : "rowid";
char *zDir = pIdxInfo->aOrderBy->desc?"DESC":"ASC";
zNew = sqlite3_mprintf(" ORDER BY %s %s", zCol, zDir);
string_concat(&zQuery, zNew, 1, &rc);
pIdxInfo->orderByConsumed = 1;
}
appendToEchoModule(pVtab->interp, "xBestIndex");;
appendToEchoModule(pVtab->interp, zQuery);
if( !zQuery ){
return rc;
}
pIdxInfo->idxNum = hashString(zQuery);
pIdxInfo->idxStr = zQuery;
pIdxInfo->needToFreeIdxStr = 1;
if( useCost ){
pIdxInfo->estimatedCost = cost;
}else if( useIdx ){
/* Approximation of log2(nRow). */
for( ii=0; ii<(sizeof(int)*8)-1; ii++ ){
if( nRow & (1<<ii) ){
pIdxInfo->estimatedCost = (double)ii;
}
}
}else{
pIdxInfo->estimatedCost = (double)nRow;
}
return rc;
}
/*
** This function is called to do the work of the xConnect() method -
** to allocate the required in-memory structures for a newly connected
** virtual table.
*/
static int echoConstructor(
sqlite3 *db,
void *pAux,
int argc, const char *const*argv,
sqlite3_vtab **ppVtab,
char **pzErr
){
int rc;
int i;
echo_vtab *pVtab;
/* Allocate the sqlite3_vtab/echo_vtab structure itself */
pVtab = sqlite3MallocZero( sizeof(*pVtab) );
if( !pVtab ){
return SQLITE_NOMEM;
}
pVtab->interp = ((EchoModule *)pAux)->interp;
pVtab->db = db;
/* Allocate echo_vtab.zThis */
pVtab->zThis = sqlite3_mprintf("%s", argv[2]);
if( !pVtab->zThis ){
echoDestructor((sqlite3_vtab *)pVtab);
return SQLITE_NOMEM;
}
/* Allocate echo_vtab.zTableName */
if( argc>3 ){
pVtab->zTableName = sqlite3_mprintf("%s", argv[3]);
dequoteString(pVtab->zTableName);
if( pVtab->zTableName && pVtab->zTableName[0]=='*' ){
char *z = sqlite3_mprintf("%s%s", argv[2], &(pVtab->zTableName[1]));
sqlite3_free(pVtab->zTableName);
pVtab->zTableName = z;
pVtab->isPattern = 1;
}
if( !pVtab->zTableName ){
echoDestructor((sqlite3_vtab *)pVtab);
return SQLITE_NOMEM;
}
}
/* Log the arguments to this function to Tcl var ::echo_module */
for(i=0; i<argc; i++){
appendToEchoModule(pVtab->interp, argv[i]);
}
/* Invoke sqlite3_declare_vtab and set up other members of the echo_vtab
** structure. If an error occurs, delete the sqlite3_vtab structure and
** return an error code.
*/
rc = echoDeclareVtab(pVtab, db);
if( rc!=SQLITE_OK ){
echoDestructor((sqlite3_vtab *)pVtab);
return rc;
}
/* Success. Set *ppVtab and return */
*ppVtab = &pVtab->base;
return SQLITE_OK;
}
