third_party/sqlite/sqlite-src-3080704/src/vdbetrace.c

   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 */
  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 */
  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   char zBase[100];         /* Initial working space */
  85
  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));
  97     }
  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;
 112         }
 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 );
 120       }
 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;
 142         }
 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++; }
 149         }
 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);
 155         }
 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);
 172         }
 173         sqlite3StrAccumAppend(&out, "'", 1);
 174 #ifdef SQLITE_TRACE_SIZE_LIMIT
 175         if( nOut<pVar->n ){
 176           sqlite3XPrintf(&out, 0, "/*+%d bytes*/", pVar->n-nOut);
 177         }
 178 #endif
 179       }
 180     }
 181   }
 182   return sqlite3StrAccumFinish(&out);
 183 }
 184
 185 #endif /* #ifndef SQLITE_OMIT_TRACE */