github.com/insionng/yougam@v0.0.0-20170714101924-2bc18d833463/libraries/pingcap/tidb/parser/yy_parser.go (about)

     1  // Copyright 2015 PingCAP, Inc.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // See the License for the specific language governing permissions and
    12  // limitations under the License.
    13  
    14  package parser
    15  
    16  import (
    17  	"regexp"
    18  	"strings"
    19  
    20  	"github.com/insionng/yougam/libraries/juju/errors"
    21  	"github.com/insionng/yougam/libraries/pingcap/tidb/ast"
    22  	"github.com/insionng/yougam/libraries/pingcap/tidb/mysql"
    23  	"github.com/insionng/yougam/libraries/pingcap/tidb/terror"
    24  )
    25  
    26  // Error instances.
    27  var (
    28  	ErrSyntax = terror.ClassParser.New(CodeSyntaxErr, "syntax error")
    29  )
    30  
    31  // Error codes.
    32  const (
    33  	CodeSyntaxErr terror.ErrCode = 1
    34  )
    35  
    36  var (
    37  	specCodePattern = regexp.MustCompile(`\/\*!(M?[0-9]{5,6})?([^*]|\*+[^*/])*\*+\/`)
    38  	specCodeStart   = regexp.MustCompile(`^\/\*!(M?[0-9]{5,6} )?[ \t]*`)
    39  	specCodeEnd     = regexp.MustCompile(`[ \t]*\*\/$`)
    40  )
    41  
    42  func trimComment(txt string) string {
    43  	txt = specCodeStart.ReplaceAllString(txt, "")
    44  	return specCodeEnd.ReplaceAllString(txt, "")
    45  }
    46  
    47  // See: http://dev.mysql.com/doc/refman/5.7/en/comments.html
    48  // Convert "/*!VersionNumber MySQL-specific-code */" to "MySQL-specific-code".
    49  // TODO: Find a better way:
    50  // 1. RegExpr is slow.
    51  // 2. Handle nested comment.
    52  func handleMySQLSpecificCode(sql string) string {
    53  	if strings.Index(sql, "/*!") == -1 {
    54  		// Fast way to check if text contains MySQL-specific code.
    55  		return sql
    56  	}
    57  	// SQL text contains MySQL-specific code. We should convert it to normal SQL text.
    58  	return specCodePattern.ReplaceAllStringFunc(sql, trimComment)
    59  }
    60  
    61  // Parse parses a query string to raw ast.StmtNode.
    62  // If charset or collation is "", default charset and collation will be used.
    63  func Parse(sql, charset, collation string) ([]ast.StmtNode, error) {
    64  	if charset == "" {
    65  		charset = mysql.DefaultCharset
    66  	}
    67  	if collation == "" {
    68  		collation = mysql.DefaultCollationName
    69  	}
    70  	sql = handleMySQLSpecificCode(sql)
    71  	l := NewLexer(sql)
    72  	l.SetCharsetInfo(charset, collation)
    73  	yyParse(l)
    74  	if len(l.Errors()) != 0 {
    75  		return nil, errors.Trace(l.Errors()[0])
    76  	}
    77  	return l.Stmts(), nil
    78  }
    79  
    80  // ParseOneStmt parses a query and returns an ast.StmtNode.
    81  // The query must have one statement, otherwise ErrSyntax is returned.
    82  func ParseOneStmt(sql, charset, collation string) (ast.StmtNode, error) {
    83  	stmts, err := Parse(sql, charset, collation)
    84  	if err != nil {
    85  		return nil, errors.Trace(err)
    86  	}
    87  	if len(stmts) != 1 {
    88  		return nil, ErrSyntax
    89  	}
    90  	return stmts[0], nil
    91  }