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Overview
Comment:Fix the application-defined function logic so that functions with a variable number of parameters can be replaced or deleted correctly. Also refactor some of the function-finder code for clarity of presentation.
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SHA1:09d5581c81fb6a9bf6a369d0abf5ef6b54637576
User & Date: drh 2012-04-07 00:09:21
Context
2012-04-10
16:05
Fix a copy/paste error in a comment in the fuzzer. No changes to code. check-in: 7433f2b5 user: drh tags: trunk
2012-04-07
00:09
Fix the application-defined function logic so that functions with a variable number of parameters can be replaced or deleted correctly. Also refactor some of the function-finder code for clarity of presentation. check-in: 09d5581c user: drh tags: trunk
2012-04-06
00:09
Update sqlite3_analyzer to correctly find all database files when the multiplexor is being used. check-in: 1bfc30cb user: drh tags: trunk
Changes
Hide Diffs Unified Diffs Ignore Whitespace Patch

Changes to src/callback.c.

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}

/* During the search for the best function definition, this procedure
** is called to test how well the function passed as the first argument
** matches the request for a function with nArg arguments in a system
** that uses encoding enc. The value returned indicates how well the
** request is matched. A higher value indicates a better match.
**
** The returned value is always between 0 and 6, as follows:
**
** 0: Not a match, or if nArg<0 and the function is has no implementation.
** 1: A variable arguments function that prefers UTF-8 when a UTF-16
**    encoding is requested, or vice versa.
** 2: A variable arguments function that uses UTF-16BE when UTF-16LE is
**    requested, or vice versa.
** 3: A variable arguments function using the same text encoding.
** 4: A function with the exact number of arguments requested that
**    prefers UTF-8 when a UTF-16 encoding is requested, or vice versa.
** 5: A function with the exact number of arguments requested that
**    prefers UTF-16LE when UTF-16BE is requested, or vice versa.
** 6: An exact match.
**
*/
static int matchQuality(FuncDef *p, int nArg, u8 enc){
  int match = 0;
  if( p->nArg==-1 || p->nArg==nArg 
   || (nArg==-1 && (p->xFunc!=0 || p->xStep!=0))
  ){
    match = 1;
    if( p->nArg==nArg || nArg==-1 ){
      match = 4;
    }
    if( enc==p->iPrefEnc ){
      match += 2;
    }
    else if( (enc==SQLITE_UTF16LE && p->iPrefEnc==SQLITE_UTF16BE) ||
             (enc==SQLITE_UTF16BE && p->iPrefEnc==SQLITE_UTF16LE) ){
      match += 1;
    }
  }



















  return match;
}

/*
** Search a FuncDefHash for a function with the given name.  Return
** a pointer to the matching FuncDef if found, or 0 if there is no match.
*/
................................................................................
** Locate a user function given a name, a number of arguments and a flag
** indicating whether the function prefers UTF-16 over UTF-8.  Return a
** pointer to the FuncDef structure that defines that function, or return
** NULL if the function does not exist.
**
** If the createFlag argument is true, then a new (blank) FuncDef
** structure is created and liked into the "db" structure if a
** no matching function previously existed.  When createFlag is true
** and the nArg parameter is -1, then only a function that accepts
** any number of arguments will be returned.
**
** If createFlag is false and nArg is -1, then the first valid
** function found is returned.  A function is valid if either xFunc
** or xStep is non-zero.
**
** If createFlag is false, then a function with the required name and
** number of arguments may be returned even if the eTextRep flag does not
** match that requested.
*/
FuncDef *sqlite3FindFunction(
  sqlite3 *db,       /* An open database */
  const char *zName, /* Name of the function.  Not null-terminated */
  int nName,         /* Number of characters in the name */
  int nArg,          /* Number of arguments.  -1 means any number */
  u8 enc,            /* Preferred text encoding */
  int createFlag     /* Create new entry if true and does not otherwise exist */
){
  FuncDef *p;         /* Iterator variable */
  FuncDef *pBest = 0; /* Best match found so far */
  int bestScore = 0;  /* Score of best match */
  int h;              /* Hash value */



  assert( enc==SQLITE_UTF8 || enc==SQLITE_UTF16LE || enc==SQLITE_UTF16BE );
  h = (sqlite3UpperToLower[(u8)zName[0]] + nName) % ArraySize(db->aFunc.a);

  /* First search for a match amongst the application-defined functions.
  */
  p = functionSearch(&db->aFunc, h, zName, nName);
  while( p ){
................................................................................
    }
  }

  /* If the createFlag parameter is true and the search did not reveal an
  ** exact match for the name, number of arguments and encoding, then add a
  ** new entry to the hash table and return it.
  */
  if( createFlag && (bestScore<6 || pBest->nArg!=nArg) && 
      (pBest = sqlite3DbMallocZero(db, sizeof(*pBest)+nName+1))!=0 ){
    pBest->zName = (char *)&pBest[1];
    pBest->nArg = (u16)nArg;
    pBest->iPrefEnc = enc;
    memcpy(pBest->zName, zName, nName);
    pBest->zName[nName] = 0;
    sqlite3FuncDefInsert(&db->aFunc, pBest);







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}

/* During the search for the best function definition, this procedure
** is called to test how well the function passed as the first argument
** matches the request for a function with nArg arguments in a system
** that uses encoding enc. The value returned indicates how well the
** request is matched. A higher value indicates a better match.
**
** If nArg is -1 that means to only return a match (non-zero) if p->nArg
** is also -1.  In other words, we are searching for a function that
** takes a variable number of arguments.
**
** If nArg is -2 that means that we are searching for any function 
** regardless of the number of arguments it uses, so return a positive
** match score for any
**
** The returned value is always between 0 and 6, as follows:
**
** 0: Not a match.
** 1: UTF8/16 conversion required and function takes any number of arguments.
** 2: UTF16 byte order change required and function takes any number of args.
** 3: encoding matches and function takes any number of arguments
** 4: UTF8/16 conversion required - argument count matches exactly
** 5: UTF16 byte order conversion required - argument count matches exactly
** 6: Perfect match:  encoding and argument count match exactly.
**
** If nArg==(-2) then any function with a non-null xStep or xFunc is
** a perfect match and any function with both xStep and xFunc NULL is
** a non-match.
*/
#define FUNC_PERFECT_MATCH 6  /* The score for a perfect match */
static int matchQuality(
  FuncDef *p,     /* The function we are evaluating for match quality */
  int nArg,       /* Desired number of arguments.  (-1)==any */
  u8 enc          /* Desired text encoding */
){
  int match;

  /* nArg of -2 is a special case */
  if( nArg==(-2) ) return (p->xFunc==0 && p->xStep==0) ? 0 : FUNC_PERFECT_MATCH;

  /* Wrong number of arguments means "no match" */
  if( p->nArg!=nArg && p->nArg>=0 ) return 0;

  /* Give a better score to a function with a specific number of arguments
  ** than to function that accepts any number of arguments. */
  if( p->nArg==nArg ){
    match = 4;
  }else{
    match = 1;
  }

  /* Bonus points if the text encoding matches */
  if( enc==p->iPrefEnc ){
    match += 2;  /* Exact encoding match */
  }else if( (enc & p->iPrefEnc & 2)!=0 ){
    match += 1;  /* Both are UTF16, but with different byte orders */
  }

  return match;
}

/*
** Search a FuncDefHash for a function with the given name.  Return
** a pointer to the matching FuncDef if found, or 0 if there is no match.
*/
................................................................................
** Locate a user function given a name, a number of arguments and a flag
** indicating whether the function prefers UTF-16 over UTF-8.  Return a
** pointer to the FuncDef structure that defines that function, or return
** NULL if the function does not exist.
**
** If the createFlag argument is true, then a new (blank) FuncDef
** structure is created and liked into the "db" structure if a
** no matching function previously existed.
**
** If nArg is -2, then the first valid function found is returned.  A
** function is valid if either xFunc or xStep is non-zero.  The nArg==(-2)
** case is used to see if zName is a valid function name for some number
** of arguments.  If nArg is -2, then createFlag must be 0.

**
** If createFlag is false, then a function with the required name and
** number of arguments may be returned even if the eTextRep flag does not
** match that requested.
*/
FuncDef *sqlite3FindFunction(
  sqlite3 *db,       /* An open database */
  const char *zName, /* Name of the function.  Not null-terminated */
  int nName,         /* Number of characters in the name */
  int nArg,          /* Number of arguments.  -1 means any number */
  u8 enc,            /* Preferred text encoding */
  u8 createFlag      /* Create new entry if true and does not otherwise exist */
){
  FuncDef *p;         /* Iterator variable */
  FuncDef *pBest = 0; /* Best match found so far */
  int bestScore = 0;  /* Score of best match */
  int h;              /* Hash value */

  assert( nArg>=(-2) );
  assert( nArg>=(-1) || createFlag==0 );
  assert( enc==SQLITE_UTF8 || enc==SQLITE_UTF16LE || enc==SQLITE_UTF16BE );
  h = (sqlite3UpperToLower[(u8)zName[0]] + nName) % ArraySize(db->aFunc.a);

  /* First search for a match amongst the application-defined functions.
  */
  p = functionSearch(&db->aFunc, h, zName, nName);
  while( p ){
................................................................................
    }
  }

  /* If the createFlag parameter is true and the search did not reveal an
  ** exact match for the name, number of arguments and encoding, then add a
  ** new entry to the hash table and return it.
  */
  if( createFlag && bestScore<FUNC_PERFECT_MATCH && 
      (pBest = sqlite3DbMallocZero(db, sizeof(*pBest)+nName+1))!=0 ){
    pBest->zName = (char *)&pBest[1];
    pBest->nArg = (u16)nArg;
    pBest->iPrefEnc = enc;
    memcpy(pBest->zName, zName, nName);
    pBest->zName[nName] = 0;
    sqlite3FuncDefInsert(&db->aFunc, pBest);

Changes to src/resolve.c.

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      testcase( pExpr->op==TK_CONST_FUNC );
      assert( !ExprHasProperty(pExpr, EP_xIsSelect) );
      zId = pExpr->u.zToken;
      nId = sqlite3Strlen30(zId);
      pDef = sqlite3FindFunction(pParse->db, zId, nId, n, enc, 0);
      if( pDef==0 ){
        pDef = sqlite3FindFunction(pParse->db, zId, nId, -1, enc, 0);
        if( pDef==0 ){
          no_such_func = 1;
        }else{
          wrong_num_args = 1;
        }
      }else{
        is_agg = pDef->xFunc==0;







|







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      testcase( pExpr->op==TK_CONST_FUNC );
      assert( !ExprHasProperty(pExpr, EP_xIsSelect) );
      zId = pExpr->u.zToken;
      nId = sqlite3Strlen30(zId);
      pDef = sqlite3FindFunction(pParse->db, zId, nId, n, enc, 0);
      if( pDef==0 ){
        pDef = sqlite3FindFunction(pParse->db, zId, nId, -2, enc, 0);
        if( pDef==0 ){
          no_such_func = 1;
        }else{
          wrong_num_args = 1;
        }
      }else{
        is_agg = pDef->xFunc==0;

Changes to src/sqliteInt.h.

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void sqlite3HaltConstraint(Parse*, int, char*, int);
Expr *sqlite3ExprDup(sqlite3*,Expr*,int);
ExprList *sqlite3ExprListDup(sqlite3*,ExprList*,int);
SrcList *sqlite3SrcListDup(sqlite3*,SrcList*,int);
IdList *sqlite3IdListDup(sqlite3*,IdList*);
Select *sqlite3SelectDup(sqlite3*,Select*,int);
void sqlite3FuncDefInsert(FuncDefHash*, FuncDef*);
FuncDef *sqlite3FindFunction(sqlite3*,const char*,int,int,u8,int);
void sqlite3RegisterBuiltinFunctions(sqlite3*);
void sqlite3RegisterDateTimeFunctions(void);
void sqlite3RegisterGlobalFunctions(void);
int sqlite3SafetyCheckOk(sqlite3*);
int sqlite3SafetyCheckSickOrOk(sqlite3*);
void sqlite3ChangeCookie(Parse*, int);








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void sqlite3HaltConstraint(Parse*, int, char*, int);
Expr *sqlite3ExprDup(sqlite3*,Expr*,int);
ExprList *sqlite3ExprListDup(sqlite3*,ExprList*,int);
SrcList *sqlite3SrcListDup(sqlite3*,SrcList*,int);
IdList *sqlite3IdListDup(sqlite3*,IdList*);
Select *sqlite3SelectDup(sqlite3*,Select*,int);
void sqlite3FuncDefInsert(FuncDefHash*, FuncDef*);
FuncDef *sqlite3FindFunction(sqlite3*,const char*,int,int,u8,u8);
void sqlite3RegisterBuiltinFunctions(sqlite3*);
void sqlite3RegisterDateTimeFunctions(void);
void sqlite3RegisterGlobalFunctions(void);
int sqlite3SafetyCheckOk(sqlite3*);
int sqlite3SafetyCheckSickOrOk(sqlite3*);
void sqlite3ChangeCookie(Parse*, int);