tokenize.c

sqlite数据库管理系统开放源码

      if( z[i] ) i++;
      *tokenType = TK_STRING;
      return i;
    }
    case '.': {
      *tokenType = TK_DOT;
      return 1;
    }
    case '0': case '1': case '2': case '3': case '4':
    case '5': case '6': case '7': case '8': case '9': {
      *tokenType = TK_INTEGER;
      for(i=1; isdigit(z[i]); i++){}
      if( z[i]=='.' && isdigit(z[i+1]) ){
        i += 2;
        while( isdigit(z[i]) ){ i++; }
        *tokenType = TK_FLOAT;
      }
      if( (z[i]=='e' || z[i]=='E') &&
           ( isdigit(z[i+1]) 
            || ((z[i+1]=='+' || z[i+1]=='-') && isdigit(z[i+2]))
           )
      ){
        i += 2;
        while( isdigit(z[i]) ){ i++; }
        *tokenType = TK_FLOAT;
      }
      return i;
    }
    case '[': {
      for(i=1; z[i] && z[i-1]!=']'; i++){}
      *tokenType = TK_ID;
      return i;
    }
    case '?': {
      *tokenType = TK_VARIABLE;
      return 1;
    }
    default: {
      if( (*z&0x80)==0 && !isIdChar[*z] ){
        break;
      }
      for(i=1; (z[i]&0x80)!=0 || isIdChar[z[i]]; i++){}
      *tokenType = sqliteKeywordCode((char*)z, i);
      return i;
    }
  }
  *tokenType = TK_ILLEGAL;
  return 1;
}

/*
** Run the parser on the given SQL string.  The parser structure is
** passed in.  An SQLITE_ status code is returned.  If an error occurs
** and pzErrMsg!=NULL then an error message might be written into 
** memory obtained from malloc() and *pzErrMsg made to point to that
** error message.  Or maybe not.
*/
int sqliteRunParser(Parse *pParse, const char *zSql, char **pzErrMsg){
  int nErr = 0;
  int i;
  void *pEngine;
  int tokenType;
  int lastTokenParsed = -1;
  sqlite *db = pParse->db;
  extern void *sqliteParserAlloc(void*(*)(int));
  extern void sqliteParserFree(void*, void(*)(void*));
  extern int sqliteParser(void*, int, Token, Parse*);

  db->flags &= ~SQLITE_Interrupt;
  pParse->rc = SQLITE_OK;
  i = 0;
  pEngine = sqliteParserAlloc((void*(*)(int))malloc);
  if( pEngine==0 ){
    sqliteSetString(pzErrMsg, "out of memory", (char*)0);
    return 1;
  }
  pParse->sLastToken.dyn = 0;
  pParse->zTail = zSql;
  while( sqlite_malloc_failed==0 && zSql[i]!=0 ){
    assert( i>=0 );
    pParse->sLastToken.z = &zSql[i];
    assert( pParse->sLastToken.dyn==0 );
    pParse->sLastToken.n = sqliteGetToken((unsigned char*)&zSql[i], &tokenType);
    i += pParse->sLastToken.n;
    switch( tokenType ){
      case TK_SPACE:
      case TK_COMMENT: {
        if( (db->flags & SQLITE_Interrupt)!=0 ){
          pParse->rc = SQLITE_INTERRUPT;
          sqliteSetString(pzErrMsg, "interrupt", (char*)0);
          goto abort_parse;
        }
        break;
      }
      case TK_ILLEGAL: {
        sqliteSetNString(pzErrMsg, "unrecognized token: \"", -1, 
           pParse->sLastToken.z, pParse->sLastToken.n, "\"", 1, 0);
        nErr++;
        goto abort_parse;
      }
      case TK_SEMI: {
        pParse->zTail = &zSql[i];
        /* Fall thru into the default case */
      }
      default: {
        sqliteParser(pEngine, tokenType, pParse->sLastToken, pParse);
        lastTokenParsed = tokenType;
        if( pParse->rc!=SQLITE_OK ){
          goto abort_parse;
        }
        break;
      }
    }
  }
abort_parse:
  if( zSql[i]==0 && nErr==0 && pParse->rc==SQLITE_OK ){
    if( lastTokenParsed!=TK_SEMI ){
      sqliteParser(pEngine, TK_SEMI, pParse->sLastToken, pParse);
      pParse->zTail = &zSql[i];
    }
    sqliteParser(pEngine, 0, pParse->sLastToken, pParse);
  }
  sqliteParserFree(pEngine, free);
  if( pParse->rc!=SQLITE_OK && pParse->rc!=SQLITE_DONE && pParse->zErrMsg==0 ){
    sqliteSetString(&pParse->zErrMsg, sqlite_error_string(pParse->rc),
                    (char*)0);
  }
  if( pParse->zErrMsg ){
    if( pzErrMsg && *pzErrMsg==0 ){
      *pzErrMsg = pParse->zErrMsg;
    }else{
      sqliteFree(pParse->zErrMsg);
    }
    pParse->zErrMsg = 0;
    if( !nErr ) nErr++;
  }
  if( pParse->pVdbe && pParse->nErr>0 ){
    sqliteVdbeDelete(pParse->pVdbe);
    pParse->pVdbe = 0;
  }
  if( pParse->pNewTable ){
    sqliteDeleteTable(pParse->db, pParse->pNewTable);
    pParse->pNewTable = 0;
  }
  if( pParse->pNewTrigger ){
    sqliteDeleteTrigger(pParse->pNewTrigger);
    pParse->pNewTrigger = 0;
  }
  if( nErr>0 && (pParse->rc==SQLITE_OK || pParse->rc==SQLITE_DONE) ){
    pParse->rc = SQLITE_ERROR;
  }
  return nErr;
}

/*
** Token types used by the sqlite_complete() routine.  See the header
** comments on that procedure for additional information.
*/
#define tkEXPLAIN 0
#define tkCREATE  1
#define tkTEMP    2
#define tkTRIGGER 3
#define tkEND     4
#define tkSEMI    5
#define tkWS      6
#define tkOTHER   7

/*
** Return TRUE if the given SQL string ends in a semicolon.
**
** Special handling is require for CREATE TRIGGER statements.
** Whenever the CREATE TRIGGER keywords are seen, the statement
** must end with ";END;".
**
** This implementation uses a state machine with 7 states:
**
**   (0) START     At the beginning or end of an SQL statement.  This routine
**                 returns 1 if it ends in the START state and 0 if it ends
**                 in any other state.
**
**   (1) EXPLAIN   The keyword EXPLAIN has been seen at the beginning of 
**                 a statement.
**
**   (2) CREATE    The keyword CREATE has been seen at the beginning of a
**                 statement, possibly preceeded by EXPLAIN and/or followed by
**                 TEMP or TEMPORARY
**
**   (3) NORMAL    We are in the middle of statement which ends with a single
**                 semicolon.
**
**   (4) TRIGGER   We are in the middle of a trigger definition that must be
**                 ended by a semicolon, the keyword END, and another semicolon.
**
**   (5) SEMI      We've seen the first semicolon in the ";END;" that occurs at
**                 the end of a trigger definition.
**
**   (6) END       We've seen the ";END" of the ";END;" that occurs at the end
**                 of a trigger difinition.
**
** Transitions between states above are determined by tokens extracted
** from the input.  The following tokens are significant:
**
**   (0) tkEXPLAIN   The "explain" keyword.
**   (1) tkCREATE    The "create" keyword.
**   (2) tkTEMP      The "temp" or "temporary" keyword.
**   (3) tkTRIGGER   The "trigger" keyword.
**   (4) tkEND       The "end" keyword.
**   (5) tkSEMI      A semicolon.
**   (6) tkWS        Whitespace
**   (7) tkOTHER     Any other SQL token.
**
** Whitespace never causes a state transition and is always ignored.
*/
int sqlite_complete(const char *zSql){
  u8 state = 0;   /* Current state, using numbers defined in header comment */
  u8 token;       /* Value of the next token */

  /* The following matrix defines the transition from one state to another
  ** according to what token is seen.  trans[state][token] returns the
  ** next state.
  */
  static const u8 trans[7][8] = {
                     /* Token:                                                */
     /* State:       **  EXPLAIN  CREATE  TEMP  TRIGGER  END  SEMI  WS  OTHER */
     /* 0   START: */ {       1,      2,    3,       3,   3,    0,  0,     3, },
     /* 1 EXPLAIN: */ {       3,      2,    3,       3,   3,    0,  1,     3, },
     /* 2  CREATE: */ {       3,      3,    2,       4,   3,    0,  2,     3, },
     /* 3  NORMAL: */ {       3,      3,    3,       3,   3,    0,  3,     3, },
     /* 4 TRIGGER: */ {       4,      4,    4,       4,   4,    5,  4,     4, },
     /* 5    SEMI: */ {       4,      4,    4,       4,   6,    5,  5,     4, },
     /* 6     END: */ {       4,      4,    4,       4,   4,    0,  6,     4, },
  };

  while( *zSql ){
    switch( *zSql ){
      case ';': {  /* A semicolon */
        token = tkSEMI;
        break;
      }
      case ' ':
      case '\r':
      case '\t':
      case '\n':
      case '\f': {  /* White space is ignored */
        token = tkWS;
        break;
      }
      case '/': {   /* C-style comments */
        if( zSql[1]!='*' ){
          token = tkOTHER;
          break;
        }
        zSql += 2;
        while( zSql[0] && (zSql[0]!='*' || zSql[1]!='/') ){ zSql++; }
        if( zSql[0]==0 ) return 0;
        zSql++;
        token = tkWS;
        break;
      }
      case '-': {   /* SQL-style comments from "--" to end of line */
        if( zSql[1]!='-' ){
          token = tkOTHER;
          break;
        }
        while( *zSql && *zSql!='\n' ){ zSql++; }
        if( *zSql==0 ) return state==0;
        token = tkWS;
        break;
      }
      case '[': {   /* Microsoft-style identifiers in [...] */
        zSql++;
        while( *zSql && *zSql!=']' ){ zSql++; }
        if( *zSql==0 ) return 0;
        token = tkOTHER;
        break;
      }
      case '"':     /* single- and double-quoted strings */
      case '\'': {
        int c = *zSql;
        zSql++;
        while( *zSql && *zSql!=c ){ zSql++; }
        if( *zSql==0 ) return 0;
        token = tkOTHER;
        break;
      }
      default: {
        if( isIdChar[(u8)*zSql] ){
          /* Keywords and unquoted identifiers */
          int nId;
          for(nId=1; isIdChar[(u8)zSql[nId]]; nId++){}
          switch( *zSql ){
            case 'c': case 'C': {
              if( nId==6 && sqliteStrNICmp(zSql, "create", 6)==0 ){
                token = tkCREATE;
              }else{
                token = tkOTHER;
              }
              break;
            }
            case 't': case 'T': {
              if( nId==7 && sqliteStrNICmp(zSql, "trigger", 7)==0 ){
                token = tkTRIGGER;
              }else if( nId==4 && sqliteStrNICmp(zSql, "temp", 4)==0 ){
                token = tkTEMP;
              }else if( nId==9 && sqliteStrNICmp(zSql, "temporary", 9)==0 ){
                token = tkTEMP;
              }else{
                token = tkOTHER;
              }
              break;
            }
            case 'e':  case 'E': {
              if( nId==3 && sqliteStrNICmp(zSql, "end", 3)==0 ){
                token = tkEND;
              }else if( nId==7 && sqliteStrNICmp(zSql, "explain", 7)==0 ){
                token = tkEXPLAIN;
              }else{
                token = tkOTHER;
              }
              break;
            }
            default: {
              token = tkOTHER;
              break;
            }
          }
          zSql += nId-1;
        }else{
          /* Operators and special symbols */
          token = tkOTHER;
        }
        break;
      }
    }
    state = trans[state][token];
    zSql++;
  }
  return state==0;
}