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1443 lines (1308 loc) · 40.7 KB
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/*
** 2006 June 10
**
** The author disclaims copyright to this source code. In place of
** a legal notice, here is a blessing:
**
** May you do good and not evil.
** May you find forgiveness for yourself and forgive others.
** May you share freely, never taking more than you give.
**
*************************************************************************
** Code for testing the virtual table interfaces. This code
** is not included in the SQLite library. It is used for automated
** testing of the SQLite library.
*/
#include "sqliteInt.h"
#if defined(INCLUDE_SQLITE_TCL_H)
# include "sqlite_tcl.h"
#else
# include "tcl.h"
#endif
#include <stdlib.h>
#include <string.h>
#ifndef SQLITE_OMIT_VIRTUALTABLE
typedef struct echo_vtab echo_vtab;
typedef struct echo_cursor echo_cursor;
/*
** The test module defined in this file uses four global Tcl variables to
** commicate with test-scripts:
**
** $::echo_module
** $::echo_module_sync_fail
** $::echo_module_begin_fail
** $::echo_module_cost
**
** The variable ::echo_module is a list. Each time one of the following
** methods is called, one or more elements are appended to the list.
** This is used for automated testing of virtual table modules.
**
** The ::echo_module_sync_fail variable is set by test scripts and read
** by code in this file. If it is set to the name of a real table in the
** the database, then all xSync operations on echo virtual tables that
** use the named table as a backing store will fail.
*/
/*
** Errors can be provoked within the following echo virtual table methods:
**
** xBestIndex xOpen xFilter xNext
** xColumn xRowid xUpdate xSync
** xBegin xRename
**
** This is done by setting the global tcl variable:
**
** echo_module_fail($method,$tbl)
**
** where $method is set to the name of the virtual table method to fail
** (i.e. "xBestIndex") and $tbl is the name of the table being echoed (not
** the name of the virtual table, the name of the underlying real table).
*/
/*
** An echo virtual-table object.
**
** echo.vtab.aIndex is an array of booleans. The nth entry is true if
** the nth column of the real table is the left-most column of an index
** (implicit or otherwise). In other words, if SQLite can optimize
** a query like "SELECT * FROM real_table WHERE col = ?".
**
** Member variable aCol[] contains copies of the column names of the real
** table.
*/
struct echo_vtab {
sqlite3_vtab base;
Tcl_Interp *interp; /* Tcl interpreter containing debug variables */
sqlite3 *db; /* Database connection */
int isPattern;
int inTransaction; /* True if within a transaction */
char *zThis; /* Name of the echo table */
char *zTableName; /* Name of the real table */
char *zLogName; /* Name of the log table */
int nCol; /* Number of columns in the real table */
int *aIndex; /* Array of size nCol. True if column has an index */
char **aCol; /* Array of size nCol. Column names */
};
/* An echo cursor object */
struct echo_cursor {
sqlite3_vtab_cursor base;
sqlite3_stmt *pStmt;
};
static int simulateVtabError(echo_vtab *p, const char *zMethod){
const char *zErr;
char zVarname[128];
zVarname[127] = '\0';
sqlite3_snprintf(127, zVarname, "echo_module_fail(%s,%s)", zMethod, p->zTableName);
zErr = Tcl_GetVar(p->interp, zVarname, TCL_GLOBAL_ONLY);
if( zErr ){
p->base.zErrMsg = sqlite3_mprintf("echo-vtab-error: %s", zErr);
}
return (zErr!=0);
}
/*
** Convert an SQL-style quoted string into a normal string by removing
** the quote characters. The conversion is done in-place. If the
** input does not begin with a quote character, then this routine
** is a no-op.
**
** Examples:
**
** "abc" becomes abc
** 'xyz' becomes xyz
** [pqr] becomes pqr
** `mno` becomes mno
*/
static void dequoteString(char *z){
int quote;
int i, j;
if( z==0 ) return;
quote = z[0];
switch( quote ){
case '\'': break;
case '"': break;
case '`': break; /* For MySQL compatibility */
case '[': quote = ']'; break; /* For MS SqlServer compatibility */
default: return;
}
for(i=1, j=0; z[i]; i++){
if( z[i]==quote ){
if( z[i+1]==quote ){
z[j++] = quote;
i++;
}else{
z[j++] = 0;
break;
}
}else{
z[j++] = z[i];
}
}
}
/*
** Retrieve the column names for the table named zTab via database
** connection db. SQLITE_OK is returned on success, or an sqlite error
** code otherwise.
**
** If successful, the number of columns is written to *pnCol. *paCol is
** set to point at sqlite3_malloc()'d space containing the array of
** nCol column names. The caller is responsible for calling sqlite3_free
** on *paCol.
*/
static int getColumnNames(
sqlite3 *db,
const char *zTab,
char ***paCol,
int *pnCol
){
char **aCol = 0;
char *zSql;
sqlite3_stmt *pStmt = 0;
int rc = SQLITE_OK;
int nCol = 0;
/* Prepare the statement "SELECT * FROM <tbl>". The column names
** of the result set of the compiled SELECT will be the same as
** the column names of table <tbl>.
*/
zSql = sqlite3_mprintf("SELECT * FROM %Q", zTab);
if( !zSql ){
rc = SQLITE_NOMEM;
goto out;
}
rc = sqlite3_prepare(db, zSql, -1, &pStmt, 0);
sqlite3_free(zSql);
if( rc==SQLITE_OK ){
int ii;
int nBytes;
char *zSpace;
nCol = sqlite3_column_count(pStmt);
/* Figure out how much space to allocate for the array of column names
** (including space for the strings themselves). Then allocate it.
*/
nBytes = sizeof(char *) * nCol;
for(ii=0; ii<nCol; ii++){
const char *zName = sqlite3_column_name(pStmt, ii);
if( !zName ){
rc = SQLITE_NOMEM;
goto out;
}
nBytes += (int)strlen(zName)+1;
}
aCol = (char **)sqlite3MallocZero(nBytes);
if( !aCol ){
rc = SQLITE_NOMEM;
goto out;
}
/* Copy the column names into the allocated space and set up the
** pointers in the aCol[] array.
*/
zSpace = (char *)(&aCol[nCol]);
for(ii=0; ii<nCol; ii++){
aCol[ii] = zSpace;
sqlite3_snprintf(nBytes, zSpace, "%s", sqlite3_column_name(pStmt,ii));
zSpace += (int)strlen(zSpace) + 1;
}
assert( (zSpace-nBytes)==(char *)aCol );
}
*paCol = aCol;
*pnCol = nCol;
out:
sqlite3_finalize(pStmt);
return rc;
}
/*
** Parameter zTab is the name of a table in database db with nCol
** columns. This function allocates an array of integers nCol in
** size and populates it according to any implicit or explicit
** indices on table zTab.
**
** If successful, SQLITE_OK is returned and *paIndex set to point
** at the allocated array. Otherwise, an error code is returned.
**
** See comments associated with the member variable aIndex above
** "struct echo_vtab" for details of the contents of the array.
*/
static int getIndexArray(
sqlite3 *db, /* Database connection */
const char *zTab, /* Name of table in database db */
int nCol,
int **paIndex
){
sqlite3_stmt *pStmt = 0;
int *aIndex = 0;
int rc;
char *zSql;
/* Allocate space for the index array */
aIndex = (int *)sqlite3MallocZero(sizeof(int) * nCol);
if( !aIndex ){
rc = SQLITE_NOMEM;
goto get_index_array_out;
}
/* Compile an sqlite pragma to loop through all indices on table zTab */
zSql = sqlite3_mprintf("PRAGMA index_list(%s)", zTab);
if( !zSql ){
rc = SQLITE_NOMEM;
goto get_index_array_out;
}
rc = sqlite3_prepare(db, zSql, -1, &pStmt, 0);
sqlite3_free(zSql);
/* For each index, figure out the left-most column and set the
** corresponding entry in aIndex[] to 1.
*/
while( pStmt && sqlite3_step(pStmt)==SQLITE_ROW ){
const char *zIdx = (const char *)sqlite3_column_text(pStmt, 1);
sqlite3_stmt *pStmt2 = 0;
if( zIdx==0 ) continue;
zSql = sqlite3_mprintf("PRAGMA index_info(%s)", zIdx);
if( !zSql ){
rc = SQLITE_NOMEM;
goto get_index_array_out;
}
rc = sqlite3_prepare(db, zSql, -1, &pStmt2, 0);
sqlite3_free(zSql);
if( pStmt2 && sqlite3_step(pStmt2)==SQLITE_ROW ){
int cid = sqlite3_column_int(pStmt2, 1);
assert( cid>=0 && cid<nCol );
aIndex[cid] = 1;
}
if( pStmt2 ){
rc = sqlite3_finalize(pStmt2);
}
if( rc!=SQLITE_OK ){
goto get_index_array_out;
}
}
get_index_array_out:
if( pStmt ){
int rc2 = sqlite3_finalize(pStmt);
if( rc==SQLITE_OK ){
rc = rc2;
}
}
if( rc!=SQLITE_OK ){
sqlite3_free(aIndex);
aIndex = 0;
}
*paIndex = aIndex;
return rc;
}
/*
** Global Tcl variable $echo_module is a list. This routine appends
** the string element zArg to that list in interpreter interp.
*/
static void appendToEchoModule(Tcl_Interp *interp, const char *zArg){
int flags = (TCL_APPEND_VALUE | TCL_LIST_ELEMENT | TCL_GLOBAL_ONLY);
Tcl_SetVar(interp, "echo_module", (zArg?zArg:""), flags);
}
/*
** This function is called from within the echo-modules xCreate and
** xConnect methods. The argc and argv arguments are copies of those
** passed to the calling method. This function is responsible for
** calling sqlite3_declare_vtab() to declare the schema of the virtual
** table being created or connected.
**
** If the constructor was passed just one argument, i.e.:
**
** CREATE TABLE t1 AS echo(t2);
**
** Then t2 is assumed to be the name of a *real* database table. The
** schema of the virtual table is declared by passing a copy of the
** CREATE TABLE statement for the real table to sqlite3_declare_vtab().
** Hence, the virtual table should have exactly the same column names and
** types as the real table.
*/
static int echoDeclareVtab(
echo_vtab *pVtab,
sqlite3 *db
){
int rc = SQLITE_OK;
if( pVtab->zTableName ){
sqlite3_stmt *pStmt = 0;
rc = sqlite3_prepare(db,
"SELECT sql FROM sqlite_master WHERE type = 'table' AND name = ?",
-1, &pStmt, 0);
if( rc==SQLITE_OK ){
sqlite3_bind_text(pStmt, 1, pVtab->zTableName, -1, 0);
if( sqlite3_step(pStmt)==SQLITE_ROW ){
int rc2;
const char *zCreateTable = (const char *)sqlite3_column_text(pStmt, 0);
rc = sqlite3_declare_vtab(db, zCreateTable);
rc2 = sqlite3_finalize(pStmt);
if( rc==SQLITE_OK ){
rc = rc2;
}
} else {
rc = sqlite3_finalize(pStmt);
if( rc==SQLITE_OK ){
rc = SQLITE_ERROR;
}
}
if( rc==SQLITE_OK ){
rc = getColumnNames(db, pVtab->zTableName, &pVtab->aCol, &pVtab->nCol);
}
if( rc==SQLITE_OK ){
rc = getIndexArray(db, pVtab->zTableName, pVtab->nCol, &pVtab->aIndex);
}
}
}
return rc;
}
/*
** This function frees all runtime structures associated with the virtual
** table pVtab.
*/
static int echoDestructor(sqlite3_vtab *pVtab){
echo_vtab *p = (echo_vtab*)pVtab;
sqlite3_free(p->aIndex);
sqlite3_free(p->aCol);
sqlite3_free(p->zThis);
sqlite3_free(p->zTableName);
sqlite3_free(p->zLogName);
sqlite3_free(p);
return 0;
}
typedef struct EchoModule EchoModule;
struct EchoModule {
Tcl_Interp *interp;
};
/*
** 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;
}
/*
** 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;
}
/*
** Echo virtual table module xConnect method.
*/
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);
}
/*
** Echo virtual table module xDisconnect method.
*/
static int echoDisconnect(sqlite3_vtab *pVtab){
appendToEchoModule(((echo_vtab *)pVtab)->interp, "xDisconnect");
return echoDestructor(pVtab);
}
/*
** 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 xOpen method.
*/
static int echoOpen(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor){
echo_cursor *pCur;
if( simulateVtabError((echo_vtab *)pVTab, "xOpen") ){
return SQLITE_ERROR;
}
pCur = sqlite3MallocZero(sizeof(echo_cursor));
*ppCursor = (sqlite3_vtab_cursor *)pCur;
return (pCur ? SQLITE_OK : SQLITE_NOMEM);
}
/*
** Echo virtual table module xClose method.
*/
static int echoClose(sqlite3_vtab_cursor *cur){
int rc;
echo_cursor *pCur = (echo_cursor *)cur;
sqlite3_stmt *pStmt = pCur->pStmt;
pCur->pStmt = 0;
sqlite3_free(pCur);
rc = sqlite3_finalize(pStmt);
return rc;
}
/*
** Return non-zero if the cursor does not currently point to a valid record
** (i.e if the scan has finished), or zero otherwise.
*/
static int echoEof(sqlite3_vtab_cursor *cur){
return (((echo_cursor *)cur)->pStmt ? 0 : 1);
}
/*
** Echo virtual table module xNext method.
*/
static int echoNext(sqlite3_vtab_cursor *cur){
int rc = SQLITE_OK;
echo_cursor *pCur = (echo_cursor *)cur;
if( simulateVtabError((echo_vtab *)(cur->pVtab), "xNext") ){
return SQLITE_ERROR;
}
if( pCur->pStmt ){
rc = sqlite3_step(pCur->pStmt);
if( rc==SQLITE_ROW ){
rc = SQLITE_OK;
}else{
rc = sqlite3_finalize(pCur->pStmt);
pCur->pStmt = 0;
}
}
return rc;
}
/*
** Echo virtual table module xColumn method.
*/
static int echoColumn(sqlite3_vtab_cursor *cur, sqlite3_context *ctx, int i){
int iCol = i + 1;
sqlite3_stmt *pStmt = ((echo_cursor *)cur)->pStmt;
if( simulateVtabError((echo_vtab *)(cur->pVtab), "xColumn") ){
return SQLITE_ERROR;
}
if( !pStmt ){
sqlite3_result_null(ctx);
}else{
assert( sqlite3_data_count(pStmt)>iCol );
sqlite3_result_value(ctx, sqlite3_column_value(pStmt, iCol));
}
return SQLITE_OK;
}
/*
** Echo virtual table module xRowid method.
*/
static int echoRowid(sqlite3_vtab_cursor *cur, sqlite_int64 *pRowid){
sqlite3_stmt *pStmt = ((echo_cursor *)cur)->pStmt;
if( simulateVtabError((echo_vtab *)(cur->pVtab), "xRowid") ){
return SQLITE_ERROR;
}
*pRowid = sqlite3_column_int64(pStmt, 0);
return SQLITE_OK;
}
/*
** Compute a simple hash of the null terminated string zString.
**
** This module uses only sqlite3_index_info.idxStr, not
** sqlite3_index_info.idxNum. So to test idxNum, when idxStr is set
** in echoBestIndex(), idxNum is set to the corresponding hash value.
** In echoFilter(), code assert()s that the supplied idxNum value is
** indeed the hash of the supplied idxStr.
*/
static int hashString(const char *zString){
u32 val = 0;
int ii;
for(ii=0; zString[ii]; ii++){
val = (val << 3) + (int)zString[ii];
}
return (int)(val&0x7fffffff);
}
/*
** 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;
}
/*
** A helper function used by echoUpdate() and echoBestIndex() for
** manipulating strings in concert with the sqlite3_mprintf() function.
**
** Parameter pzStr points to a pointer to a string allocated with
** sqlite3_mprintf. The second parameter, zAppend, points to another
** string. The two strings are concatenated together and *pzStr
** set to point at the result. The initial buffer pointed to by *pzStr
** is deallocated via sqlite3_free().
**
** If the third argument, doFree, is true, then sqlite3_free() is
** also called to free the buffer pointed to by zAppend.
*/
static void string_concat(char **pzStr, char *zAppend, int doFree, int *pRc){
char *zIn = *pzStr;
if( !zAppend && doFree && *pRc==SQLITE_OK ){
*pRc = SQLITE_NOMEM;
}
if( *pRc!=SQLITE_OK ){
sqlite3_free(zIn);
zIn = 0;
}else{
if( zIn ){
char *zTemp = zIn;
zIn = sqlite3_mprintf("%s%s", zIn, zAppend);
sqlite3_free(zTemp);
}else{
zIn = sqlite3_mprintf("%s", zAppend);
}
if( !zIn ){
*pRc = SQLITE_NOMEM;
}
}
*pzStr = zIn;
if( doFree ){
sqlite3_free(zAppend);
}
}
/*
** This function returns a pointer to an sqlite3_malloc()ed buffer
** containing the select-list (the thing between keywords SELECT and FROM)
** to query the underlying real table with for the scan described by
** argument pIdxInfo.
**
** If the current SQLite version is earlier than 3.10.0, this is just "*"
** (select all columns). Or, for version 3.10.0 and greater, the list of
** columns identified by the pIdxInfo->colUsed mask.
*/
static char *echoSelectList(echo_vtab *pTab, sqlite3_index_info *pIdxInfo){
char *zRet = 0;
if( sqlite3_libversion_number()<3010000 ){
zRet = sqlite3_mprintf(", *");
}else{
int i;
for(i=0; i<pTab->nCol; i++){
if( pIdxInfo->colUsed & ((sqlite3_uint64)1 << (i>=63 ? 63 : i)) ){
zRet = sqlite3_mprintf("%z, %s", zRet, pTab->aCol[i]);
}else{
zRet = sqlite3_mprintf("%z, NULL", zRet);
}
if( !zRet ) break;
}
}
return zRet;
}
/*
** 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 *zNewCol = 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, zNewCol);
} else {
zNew = sqlite3_mprintf(" %s %s %s ?", zSep, zNewCol, 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 *zNewCol = iCol>=0 ? pVtab->aCol[iCol] : "rowid";
char *zDir = pIdxInfo->aOrderBy->desc?"DESC":"ASC";
zNew = sqlite3_mprintf(" ORDER BY %s %s", zNewCol, 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;
}
/*
** The xUpdate method for echo module virtual tables.
**
** apData[0] apData[1] apData[2..]
**
** INTEGER DELETE
**
** INTEGER NULL (nCol args) UPDATE (do not set rowid)
** INTEGER INTEGER (nCol args) UPDATE (with SET rowid = <arg1>)
**
** NULL NULL (nCol args) INSERT INTO (automatic rowid value)
** NULL INTEGER (nCol args) INSERT (incl. rowid value)
**
*/
int echoUpdate(
sqlite3_vtab *tab,
int nData,
sqlite3_value **apData,
sqlite_int64 *pRowid
){
echo_vtab *pVtab = (echo_vtab *)tab;
sqlite3 *db = pVtab->db;
int rc = SQLITE_OK;
sqlite3_stmt *pStmt = 0;
char *z = 0; /* SQL statement to execute */
int bindArgZero = 0; /* True to bind apData[0] to sql var no. nData */
int bindArgOne = 0; /* True to bind apData[1] to sql var no. 1 */
int i; /* Counter variable used by for loops */
assert( nData==pVtab->nCol+2 || nData==1 );
/* Ticket #3083 - make sure we always start a transaction prior to
** making any changes to a virtual table */
assert( pVtab->inTransaction );
if( simulateVtabError(pVtab, "xUpdate") ){
return SQLITE_ERROR;
}
/* If apData[0] is an integer and nData>1 then do an UPDATE */
if( nData>1 && sqlite3_value_type(apData[0])==SQLITE_INTEGER ){
char *zSep = " SET";
z = sqlite3_mprintf("UPDATE %Q", pVtab->zTableName);
if( !z ){
rc = SQLITE_NOMEM;
}