1 /*
2 ** 2009 November 25
3 **
4 ** The author disclaims copyright to this source code. In place of
5 ** a legal notice, here is a blessing:
6 **
7 ** May you do good and not evil.
8 ** May you find forgiveness for yourself and forgive others.
9 ** May you share freely, never taking more than you give.
10 **
11 *************************************************************************
12 **
13 ** This file contains code used to insert the values of host parameters
14 ** (aka "wildcards") into the SQL text output by sqlite3_trace().
15 **
16 ** The Vdbe parse-tree explainer is also found here.
17 */
18 #include "sqliteInt.h"
19 #include "vdbeInt.h"
20
21 #ifndef SQLITE_OMIT_TRACE
22
23 /*
24 ** zSql is a zero-terminated string of UTF-8 SQL text. Return the number of
25 ** bytes in this text up to but excluding the first character in
26 ** a host parameter. If the text contains no host parameters, return
27 ** the total number of bytes in the text.
28 */
findNextHostParameter(const char * zSql,int * pnToken)29 static int findNextHostParameter(const char *zSql, int *pnToken){
30 int tokenType;
31 int nTotal = 0;
32 int n;
33
34 *pnToken = 0;
35 while( zSql[0] ){
36 n = sqlite3GetToken((u8*)zSql, &tokenType);
37 assert( n>0 && tokenType!=TK_ILLEGAL );
38 if( tokenType==TK_VARIABLE ){
39 *pnToken = n;
40 break;
41 }
42 nTotal += n;
43 zSql += n;
44 }
45 return nTotal;
46 }
47
48 /*
49 ** This function returns a pointer to a nul-terminated string in memory
50 ** obtained from sqlite3DbMalloc(). If sqlite3.nVdbeExec is 1, then the
51 ** string contains a copy of zRawSql but with host parameters expanded to
52 ** their current bindings. Or, if sqlite3.nVdbeExec is greater than 1,
53 ** then the returned string holds a copy of zRawSql with "-- " prepended
54 ** to each line of text.
55 **
56 ** If the SQLITE_TRACE_SIZE_LIMIT macro is defined to an integer, then
57 ** then long strings and blobs are truncated to that many bytes. This
58 ** can be used to prevent unreasonably large trace strings when dealing
59 ** with large (multi-megabyte) strings and blobs.
60 **
61 ** The calling function is responsible for making sure the memory returned
62 ** is eventually freed.
63 **
64 ** ALGORITHM: Scan the input string looking for host parameters in any of
65 ** these forms: ?, ?N, $A, @A, :A. Take care to avoid text within
66 ** string literals, quoted identifier names, and comments. For text forms,
67 ** the host parameter index is found by scanning the prepared
68 ** statement for the corresponding OP_Variable opcode. Once the host
69 ** parameter index is known, locate the value in p->aVar[]. Then render
70 ** the value as a literal in place of the host parameter name.
71 */
sqlite3VdbeExpandSql(Vdbe * p,const char * zRawSql)72 char *sqlite3VdbeExpandSql(
73 Vdbe *p, /* The prepared statement being evaluated */
74 const char *zRawSql /* Raw text of the SQL statement */
75 ){
76 sqlite3 *db; /* The database connection */
77 int idx = 0; /* Index of a host parameter */
78 int nextIndex = 1; /* Index of next ? host parameter */
79 int n; /* Length of a token prefix */
80 int nToken; /* Length of the parameter token */
81 int i; /* Loop counter */
82 Mem *pVar; /* Value of a host parameter */
83 StrAccum out; /* Accumulate the output here */
84 #ifndef SQLITE_OMIT_UTF16
85 Mem utf8; /* Used to convert UTF16 into UTF8 for display */
86 #endif
87
88 db = p->db;
89 sqlite3StrAccumInit(&out, 0, 0, 0, db->aLimit[SQLITE_LIMIT_LENGTH]);
90 if( db->nVdbeExec>1 ){
91 while( *zRawSql ){
92 const char *zStart = zRawSql;
93 while( *(zRawSql++)!='\n' && *zRawSql );
94 sqlite3_str_append(&out, "-- ", 3);
95 assert( (zRawSql - zStart) > 0 );
96 sqlite3_str_append(&out, zStart, (int)(zRawSql-zStart));
97 }
98 }else if( p->nVar==0 ){
99 sqlite3_str_append(&out, zRawSql, sqlite3Strlen30(zRawSql));
100 }else{
101 while( zRawSql[0] ){
102 n = findNextHostParameter(zRawSql, &nToken);
103 assert( n>0 );
104 sqlite3_str_append(&out, zRawSql, n);
105 zRawSql += n;
106 assert( zRawSql[0] || nToken==0 );
107 if( nToken==0 ) break;
108 if( zRawSql[0]=='?' ){
109 if( nToken>1 ){
110 assert( sqlite3Isdigit(zRawSql[1]) );
111 sqlite3GetInt32(&zRawSql[1], &idx);
112 }else{
113 idx = nextIndex;
114 }
115 }else{
116 assert( zRawSql[0]==':' || zRawSql[0]=='$' ||
117 zRawSql[0]=='@' || zRawSql[0]=='#' );
118 testcase( zRawSql[0]==':' );
119 testcase( zRawSql[0]=='$' );
120 testcase( zRawSql[0]=='@' );
121 testcase( zRawSql[0]=='#' );
122 idx = sqlite3VdbeParameterIndex(p, zRawSql, nToken);
123 assert( idx>0 );
124 }
125 zRawSql += nToken;
126 nextIndex = MAX(idx + 1, nextIndex);
127 assert( idx>0 && idx<=p->nVar );
128 pVar = &p->aVar[idx-1];
129 if( pVar->flags & MEM_Null ){
130 sqlite3_str_append(&out, "NULL", 4);
131 }else if( pVar->flags & (MEM_Int|MEM_IntReal) ){
132 sqlite3_str_appendf(&out, "%lld", pVar->u.i);
133 }else if( pVar->flags & MEM_Real ){
134 sqlite3_str_appendf(&out, "%!.15g", pVar->u.r);
135 }else if( pVar->flags & MEM_Str ){
136 int nOut; /* Number of bytes of the string text to include in output */
137 #ifndef SQLITE_OMIT_UTF16
138 u8 enc = ENC(db);
139 if( enc!=SQLITE_UTF8 ){
140 memset(&utf8, 0, sizeof(utf8));
141 utf8.db = db;
142 sqlite3VdbeMemSetStr(&utf8, pVar->z, pVar->n, enc, SQLITE_STATIC);
143 if( SQLITE_NOMEM==sqlite3VdbeChangeEncoding(&utf8, SQLITE_UTF8) ){
144 out.accError = SQLITE_NOMEM;
145 out.nAlloc = 0;
146 }
147 pVar = &utf8;
148 }
149 #endif
150 nOut = pVar->n;
151 #ifdef SQLITE_TRACE_SIZE_LIMIT
152 if( nOut>SQLITE_TRACE_SIZE_LIMIT ){
153 nOut = SQLITE_TRACE_SIZE_LIMIT;
154 while( nOut<pVar->n && (pVar->z[nOut]&0xc0)==0x80 ){ nOut++; }
155 }
156 #endif
157 sqlite3_str_appendf(&out, "'%.*q'", nOut, pVar->z);
158 #ifdef SQLITE_TRACE_SIZE_LIMIT
159 if( nOut<pVar->n ){
160 sqlite3_str_appendf(&out, "/*+%d bytes*/", pVar->n-nOut);
161 }
162 #endif
163 #ifndef SQLITE_OMIT_UTF16
164 if( enc!=SQLITE_UTF8 ) sqlite3VdbeMemRelease(&utf8);
165 #endif
166 }else if( pVar->flags & MEM_Zero ){
167 sqlite3_str_appendf(&out, "zeroblob(%d)", pVar->u.nZero);
168 }else{
169 int nOut; /* Number of bytes of the blob to include in output */
170 assert( pVar->flags & MEM_Blob );
171 sqlite3_str_append(&out, "x'", 2);
172 nOut = pVar->n;
173 #ifdef SQLITE_TRACE_SIZE_LIMIT
174 if( nOut>SQLITE_TRACE_SIZE_LIMIT ) nOut = SQLITE_TRACE_SIZE_LIMIT;
175 #endif
176 for(i=0; i<nOut; i++){
177 sqlite3_str_appendf(&out, "%02x", pVar->z[i]&0xff);
178 }
179 sqlite3_str_append(&out, "'", 1);
180 #ifdef SQLITE_TRACE_SIZE_LIMIT
181 if( nOut<pVar->n ){
182 sqlite3_str_appendf(&out, "/*+%d bytes*/", pVar->n-nOut);
183 }
184 #endif
185 }
186 }
187 }
188 if( out.accError ) sqlite3_str_reset(&out);
189 return sqlite3StrAccumFinish(&out);
190 }
191
192 #endif /* #ifndef SQLITE_OMIT_TRACE */
193