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[chromium-blink-merge.git] / third_party / sqlite / sqlite-src-3080704 / src / vdbetrace.c
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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.
11 *************************************************************************
13 ** This file contains code used to insert the values of host parameters
14 ** (aka "wildcards") into the SQL text output by sqlite3_trace().
16 ** The Vdbe parse-tree explainer is also found here.
18 #include "sqliteInt.h"
19 #include "vdbeInt.h"
21 #ifndef SQLITE_OMIT_TRACE
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.
29 static int findNextHostParameter(const char *zSql, int *pnToken){
30 int tokenType;
31 int nTotal = 0;
32 int n;
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;
42 nTotal += n;
43 zSql += n;
45 return nTotal;
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.
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.
61 ** The calling function is responsible for making sure the memory returned
62 ** is eventually freed.
64 ** ALGORITHM: Scan the input string looking for host parameters in any of
65 ** these forms: ?, ?N, $A, @A, :A. Take care to avoid text within
66 ** string literals, quoted identifier names, and comments. For text forms,
67 ** the host parameter index is found by scanning the prepared
68 ** statement for the corresponding OP_Variable opcode. Once the host
69 ** parameter index is known, locate the value in p->aVar[]. Then render
70 ** the value as a literal in place of the host parameter name.
72 char *sqlite3VdbeExpandSql(
73 Vdbe *p, /* The prepared statement being evaluated */
74 const char *zRawSql /* Raw text of the SQL statement */
76 sqlite3 *db; /* The database connection */
77 int idx = 0; /* Index of a host parameter */
78 int nextIndex = 1; /* Index of next ? host parameter */
79 int n; /* Length of a token prefix */
80 int nToken; /* Length of the parameter token */
81 int i; /* Loop counter */
82 Mem *pVar; /* Value of a host parameter */
83 StrAccum out; /* Accumulate the output here */
84 char zBase[100]; /* Initial working space */
86 db = p->db;
87 sqlite3StrAccumInit(&out, zBase, sizeof(zBase),
88 db->aLimit[SQLITE_LIMIT_LENGTH]);
89 out.db = db;
90 if( db->nVdbeExec>1 ){
91 while( *zRawSql ){
92 const char *zStart = zRawSql;
93 while( *(zRawSql++)!='\n' && *zRawSql );
94 sqlite3StrAccumAppend(&out, "-- ", 3);
95 assert( (zRawSql - zStart) > 0 );
96 sqlite3StrAccumAppend(&out, zStart, (int)(zRawSql-zStart));
98 }else{
99 while( zRawSql[0] ){
100 n = findNextHostParameter(zRawSql, &nToken);
101 assert( n>0 );
102 sqlite3StrAccumAppend(&out, zRawSql, n);
103 zRawSql += n;
104 assert( zRawSql[0] || nToken==0 );
105 if( nToken==0 ) break;
106 if( zRawSql[0]=='?' ){
107 if( nToken>1 ){
108 assert( sqlite3Isdigit(zRawSql[1]) );
109 sqlite3GetInt32(&zRawSql[1], &idx);
110 }else{
111 idx = nextIndex;
113 }else{
114 assert( zRawSql[0]==':' || zRawSql[0]=='$' || zRawSql[0]=='@' );
115 testcase( zRawSql[0]==':' );
116 testcase( zRawSql[0]=='$' );
117 testcase( zRawSql[0]=='@' );
118 idx = sqlite3VdbeParameterIndex(p, zRawSql, nToken);
119 assert( idx>0 );
121 zRawSql += nToken;
122 nextIndex = idx + 1;
123 assert( idx>0 && idx<=p->nVar );
124 pVar = &p->aVar[idx-1];
125 if( pVar->flags & MEM_Null ){
126 sqlite3StrAccumAppend(&out, "NULL", 4);
127 }else if( pVar->flags & MEM_Int ){
128 sqlite3XPrintf(&out, 0, "%lld", pVar->u.i);
129 }else if( pVar->flags & MEM_Real ){
130 sqlite3XPrintf(&out, 0, "%!.15g", pVar->u.r);
131 }else if( pVar->flags & MEM_Str ){
132 int nOut; /* Number of bytes of the string text to include in output */
133 #ifndef SQLITE_OMIT_UTF16
134 u8 enc = ENC(db);
135 Mem utf8;
136 if( enc!=SQLITE_UTF8 ){
137 memset(&utf8, 0, sizeof(utf8));
138 utf8.db = db;
139 sqlite3VdbeMemSetStr(&utf8, pVar->z, pVar->n, enc, SQLITE_STATIC);
140 sqlite3VdbeChangeEncoding(&utf8, SQLITE_UTF8);
141 pVar = &utf8;
143 #endif
144 nOut = pVar->n;
145 #ifdef SQLITE_TRACE_SIZE_LIMIT
146 if( nOut>SQLITE_TRACE_SIZE_LIMIT ){
147 nOut = SQLITE_TRACE_SIZE_LIMIT;
148 while( nOut<pVar->n && (pVar->z[nOut]&0xc0)==0x80 ){ nOut++; }
150 #endif
151 sqlite3XPrintf(&out, 0, "'%.*q'", nOut, pVar->z);
152 #ifdef SQLITE_TRACE_SIZE_LIMIT
153 if( nOut<pVar->n ){
154 sqlite3XPrintf(&out, 0, "/*+%d bytes*/", pVar->n-nOut);
156 #endif
157 #ifndef SQLITE_OMIT_UTF16
158 if( enc!=SQLITE_UTF8 ) sqlite3VdbeMemRelease(&utf8);
159 #endif
160 }else if( pVar->flags & MEM_Zero ){
161 sqlite3XPrintf(&out, 0, "zeroblob(%d)", pVar->u.nZero);
162 }else{
163 int nOut; /* Number of bytes of the blob to include in output */
164 assert( pVar->flags & MEM_Blob );
165 sqlite3StrAccumAppend(&out, "x'", 2);
166 nOut = pVar->n;
167 #ifdef SQLITE_TRACE_SIZE_LIMIT
168 if( nOut>SQLITE_TRACE_SIZE_LIMIT ) nOut = SQLITE_TRACE_SIZE_LIMIT;
169 #endif
170 for(i=0; i<nOut; i++){
171 sqlite3XPrintf(&out, 0, "%02x", pVar->z[i]&0xff);
173 sqlite3StrAccumAppend(&out, "'", 1);
174 #ifdef SQLITE_TRACE_SIZE_LIMIT
175 if( nOut<pVar->n ){
176 sqlite3XPrintf(&out, 0, "/*+%d bytes*/", pVar->n-nOut);
178 #endif
182 return sqlite3StrAccumFinish(&out);
185 #endif /* #ifndef SQLITE_OMIT_TRACE */