/*
** 2009 November 25
**
** 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.
**
*************************************************************************
**
** This file contains code used to insert the values of host parameters
** (aka "wildcards") into the SQL text output by sqlite3_trace().
**
** The Vdbe parse-tree explainer is also found here.
*/
#include "sqliteInt.h"
#include "vdbeInt.h"
#ifndef SQLITE_OMIT_TRACE
/*
** zSql is a zero-terminated string of UTF-8 SQL text. Return the number of
** bytes in this text up to but excluding the first character in
** a host parameter. If the text contains no host parameters, return
** the total number of bytes in the text.
*/
static int findNextHostParameter(const char *zSql, int *pnToken){
int tokenType;
int nTotal = 0;
int n;
*pnToken = 0;
while( zSql[0] ){
n = sqlite3GetToken((u8*)zSql, &tokenType);
assert( n>0 && tokenType!=TK_ILLEGAL );
if( tokenType==TK_VARIABLE ){
*pnToken = n;
break;
}
nTotal += n;
zSql += n;
}
return nTotal;
}
/*
** This function returns a pointer to a nul-terminated string in memory
** obtained from sqlite3DbMalloc(). If sqlite3.nVdbeExec is 1, then the
** string contains a copy of zRawSql but with host parameters expanded to
** their current bindings. Or, if sqlite3.nVdbeExec is greater than 1,
** then the returned string holds a copy of zRawSql with "-- " prepended
** to each line of text.
**
** If the SQLITE_TRACE_SIZE_LIMIT macro is defined to an integer, then
** then long strings and blobs are truncated to that many bytes. This
** can be used to prevent unreasonably large trace strings when dealing
** with large (multi-megabyte) strings and blobs.
**
** The calling function is responsible for making sure the memory returned
** is eventually freed.
**
** ALGORITHM: Scan the input string looking for host parameters in any of
** these forms: ?, ?N, $A, @A, :A. Take care to avoid text within
** string literals, quoted identifier names, and comments. For text forms,
** the host parameter index is found by scanning the prepared
** statement for the corresponding OP_Variable opcode. Once the host
** parameter index is known, locate the value in p->aVar[]. Then render
** the value as a literal in place of the host parameter name.
*/
char *sqlite3VdbeExpandSql(
Vdbe *p, /* The prepared statement being evaluated */
const char *zRawSql /* Raw text of the SQL statement */
){
sqlite3 *db; /* The database connection */
int idx = 0; /* Index of a host parameter */
int nextIndex = 1; /* Index of next ? host parameter */
int n; /* Length of a token prefix */
int nToken; /* Length of the parameter token */
int i; /* Loop counter */
Mem *pVar; /* Value of a host parameter */
StrAccum out; /* Accumulate the output here */
char zBase[100]; /* Initial working space */
db = p->db;
sqlite3StrAccumInit(&out, db, zBase, sizeof(zBase),
db->aLimit[SQLITE_LIMIT_LENGTH]);
if( db->nVdbeExec>1 ){
while( *zRawSql ){
const char *zStart = zRawSql;
while( *(zRawSql++)!='\n' && *zRawSql );
sqlite3StrAccumAppend(&out, "-- ", 3);
assert( (zRawSql - zStart) > 0 );
sqlite3StrAccumAppend(&out, zStart, (int)(zRawSql-zStart));
}
}else if( p->nVar==0 ){
sqlite3StrAccumAppend(&out, zRawSql, sqlite3Strlen30(zRawSql));
}else{
while( zRawSql[0] ){
n = findNextHostParameter(zRawSql, &nToken);
assert( n>0 );
sqlite3StrAccumAppend(&out, zRawSql, n);
zRawSql += n;
assert( zRawSql[0] || nToken==0 );
if( nToken==0 ) break;
if( zRawSql[0]=='?' ){
if( nToken>1 ){
assert( sqlite3Isdigit(zRawSql[1]) );
sqlite3GetInt32(&zRawSql[1], &idx);
}else{
idx = nextIndex;
}
}else{
assert( zRawSql[0]==':' || zRawSql[0]=='$' ||
zRawSql[0]=='@' || zRawSql[0]=='#' );
testcase( zRawSql[0]==':' );
testcase( zRawSql[0]=='$' );
testcase( zRawSql[0]=='@' );
testcase( zRawSql[0]=='#' );
idx = sqlite3VdbeParameterIndex(p, zRawSql, nToken);
assert( idx>0 );
}
zRawSql += nToken;
nextIndex = idx + 1;
assert( idx>0 && idx<=p->nVar );
pVar = &p->aVar[idx-1];
if( pVar->flags & MEM_Null ){
sqlite3StrAccumAppend(&out, "NULL", 4);
}else if( pVar->flags & MEM_Int ){
sqlite3XPrintf(&out, "%lld", pVar->u.i);
}else if( pVar->flags & MEM_Real ){
sqlite3XPrintf(&out, "%!.15g", pVar->u.r);
}else if( pVar->flags & MEM_Str ){
int nOut; /* Number of bytes of the string text to include in output */
#ifndef SQLITE_OMIT_UTF16
u8 enc = ENC(db);
Mem utf8;
if( enc!=SQLITE_UTF8 ){
memset(&utf8, 0, sizeof(utf8));
utf8.db = db;
sqlite3VdbeMemSetStr(&utf8, pVar->z, pVar->n, enc, SQLITE_STATIC);
sqlite3VdbeChangeEncoding(&utf8, SQLITE_UTF8);
pVar = &utf8;
}
#endif
nOut = pVar->n;
#ifdef SQLITE_TRACE_SIZE_LIMIT
if( nOut>SQLITE_TRACE_SIZE_LIMIT ){
nOut = SQLITE_TRACE_SIZE_LIMIT;
while( nOut<pVar->n && (pVar->z[nOut]&0xc0)==0x80 ){ nOut++; }
}
#endif
sqlite3XPrintf(&out, "'%.*q'", nOut, pVar->z);
#ifdef SQLITE_TRACE_SIZE_LIMIT
if( nOut<pVar->n ){
sqlite3XPrintf(&out, "/*+%d bytes*/", pVar->n-nOut);
}
#endif
#ifndef SQLITE_OMIT_UTF16
if( enc!=SQLITE_UTF8 ) sqlite3VdbeMemRelease(&utf8);
#endif
}else if( pVar->flags & MEM_Zero ){
sqlite3XPrintf(&out, "zeroblob(%d)", pVar->u.nZero);
}else{
int nOut; /* Number of bytes of the blob to include in output */
assert( pVar->flags & MEM_Blob );
sqlite3StrAccumAppend(&out, "x'", 2);
nOut = pVar->n;
#ifdef SQLITE_TRACE_SIZE_LIMIT
if( nOut>SQLITE_TRACE_SIZE_LIMIT ) nOut = SQLITE_TRACE_SIZE_LIMIT;
#endif
for(i=0; i<nOut; i++){
sqlite3XPrintf(&out, "%02x", pVar->z[i]&0xff);
}
sqlite3StrAccumAppend(&out, "'", 1);
#ifdef SQLITE_TRACE_SIZE_LIMIT
if( nOut<pVar->n ){
sqlite3XPrintf(&out, "/*+%d bytes*/", pVar->n-nOut);
}
#endif
}
}
}
return sqlite3StrAccumFinish(&out);
}
#endif /* #ifndef SQLITE_OMIT_TRACE */