Let virtual table implementations know which SQL string is being executed

src/sqlite.h.in

@@ -7076,6 +7076,9 @@ struct sqlite3_module {
   /* The methods above are in versions 1 and 2 of the sqlite_module object.
   ** Those below are for version 3 and greater. */
   int (*xShadowName)(const char*);
+  /* The methods below relate to features contributed by the community and
+  ** are available for version 700 and greater. */
+  int (*xPreparedSql)(sqlite3_vtab_cursor*, const char*);
 };
 
 /*

src/test8.c

@@ -1293,6 +1293,17 @@ static int echoRollbackTo(sqlite3_vtab *pVTab, int iSavepoint){
   return SQLITE_OK;
 }
 
+static int echoShadowName(const char *name){
+  assert( name );
+  return SQLITE_OK;
+}
+
+static int echoPreparedSql(sqlite3_vtab_cursor *cur, const char *sql){
+  assert( cur );
+  assert( sql );
+  return SQLITE_OK;
+}
+
 /*
 ** A virtual table module that merely "echos" the contents of another
 ** table (like an SQL VIEW).
@@ -1321,7 +1332,7 @@ static sqlite3_module echoModule = {
 };
 
 static sqlite3_module echoModuleV2 = {
-  2,                         /* iVersion */
+  700,                       /* iVersion */
   echoCreate,
   echoConnect,
   echoBestIndex,
@@ -1343,7 +1354,9 @@ static sqlite3_module echoModuleV2 = {
   echoRename,                /* xRename - rename the table */
   echoSavepoint,
   echoRelease,
-  echoRollbackTo
+  echoRollbackTo,
+  echoShadowName,
+  echoPreparedSql,
 };
 
 /*

src/vdbe.c

@@ -8072,6 +8072,39 @@ case OP_VInitIn: {        /* out2 */
 }
 #endif /* SQLITE_OMIT_VIRTUALTABLE */
 
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/* Opcode: VPreparedSql P1 * * * *
+**
+** P1 is a cursor opened using VOpen.
+**
+** This opcode invokes the xPreparedSql method on the virtual table specified
+** by P1. The SQL text parameter to xPreparedSql is obtained from Vdbe* `p`.
+**
+*/
+case OP_VPreparedSql: {
+  const sqlite3_module *pModule;
+  sqlite3_vtab_cursor *pVCur;
+  sqlite3_vtab *pVtab;
+  VdbeCursor *pCur;
+
+  pCur = p->apCsr[pOp->p1];
+  assert( pCur!=0 );
+  assert( pCur->eCurType==CURTYPE_VTAB );
+  pVCur = pCur->uc.pVCur;
+  pVtab = pVCur->pVtab;
+  pModule = pVtab->pModule;
+
+  /* Invoke the xPreparedSql method */
+   if( pModule->iVersion>=700 ){
+    if( pModule->xPreparedSql && p->zSql ){
+      rc = pModule->xPreparedSql(pVCur, p->zSql);
+      if( rc ) goto abort_due_to_error;
+    }
+  }
+
+  break;
+}
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
 
 #ifndef SQLITE_OMIT_VIRTUALTABLE
 /* Opcode: VFilter P1 P2 P3 P4 *

src/wherecode.c

@@ -1415,6 +1415,8 @@ Bitmask sqlite3WhereCodeOneLoopStart(
     int addrNotFound;
     int nConstraint = pLoop->nLTerm;
 
+    sqlite3VdbeAddOp1(v, OP_VPreparedSql, iCur);
+
     iReg = sqlite3GetTempRange(pParse, nConstraint+2);
     addrNotFound = pLevel->addrBrk;
     for(j=0; j<nConstraint; j++){

test/rowvaluevtab.test

@@ -22,6 +22,10 @@ ifcapable !vtab {
 
 register_echo_module db
 
+#############
+# Test echo
+#############
+
 do_execsql_test 1.0 {
   CREATE TABLE t1(a, b, c);
   CREATE INDEX t1b ON t1(b);
@@ -92,4 +96,40 @@ do_vfilter4_test 1.4f {
   SELECT a FROM e1 WHERE (b, c) IN ( VALUES(2, 2) )
 } {{SELECT rowid, a, b, c FROM 't1' WHERE b = ?}}
 
+#######################################################################
+# Test echo_v2. We simply want to ensure that OP_VPreparedSql executes
+#######################################################################
+
+do_execsql_test 2.0 {
+  CREATE TABLE t2(a, b, c);
+  CREATE INDEX t2b ON t2(b);
+  INSERT INTO t2 VALUES('one', 1, 1);
+  INSERT INTO t2 VALUES('two', 1, 2);
+  INSERT INTO t2 VALUES('three', 1, 3);
+
+  WITH s(i) AS (
+    SELECT 1 UNION ALL SELECT i+1 FROM s WHERE i<10000
+  ) INSERT INTO t2 SELECT NULL, NULL, NULL FROM s;
+  CREATE VIRTUAL TABLE e2 USING echo_v2(t2);
+}
+
+proc do_vpreparedsql1_test {tn sql expected} {
+  set rc -1
+  db eval "explain $sql" {
+    if {$opcode=="VPreparedSql"} {
+      set rc 0
+    }
+  }
+  if {$rc != $expected} {
+    error "Unexpected result $rc, was hoping for $expected"
+  }
+}
+
+do_execsql_test 2.1 {
+  SELECT a FROM e2 WHERE (b, c) IN ( VALUES(1, 3) )
+} {three}
+do_vpreparedsql1_test 2.1f {
+  SELECT a FROM e2 WHERE (b, c) IN ( VALUES(2, 2) )
+} {0}
+
 finish_test