sqlparser/analyzer.go at master · dearcode/sqlparser · GitHub

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Licensed under the Apache License, Version 2.0 (the "License");

you may not use this file except in compliance with the License.

You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software

distributed under the License is distributed on an "AS IS" BASIS,

WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

See the License for the specific language governing permissions and

limitations under the License.

package sqlparser

// analyzer.go contains utility analysis functions.

import (

"fmt"

"strconv"

"strings"

"unicode"

"vitess.io/vitess/go/sqltypes"

"vitess.io/vitess/go/vt/vterrors"

vtrpcpb "vitess.io/vitess/go/vt/proto/vtrpc"

)

// These constants are used to identify the SQL statement type.

const (

StmtSelect = iota

StmtStream

StmtInsert

StmtReplace

StmtUpdate

StmtDelete

StmtDDL

StmtBegin

StmtCommit

StmtRollback

StmtSet

StmtShow

StmtUse

StmtOther

StmtUnknown

StmtComment

)

// Preview analyzes the beginning of the query using a simpler and faster

// textual comparison to identify the statement type.

func Preview(sql string) int {

trimmed := StripLeadingComments(sql)

firstWord := trimmed

if end := strings.IndexFunc(trimmed, unicode.IsSpace); end != -1 {

firstWord = trimmed[:end]

}

// Comparison is done in order of priority.

loweredFirstWord := strings.ToLower(firstWord)

switch loweredFirstWord {

case "select":

return StmtSelect

case "stream":

return StmtStream

case "insert":

return StmtInsert

case "replace":

return StmtReplace

case "update":

return StmtUpdate

case "delete":

return StmtDelete

}

// For the following statements it is not sufficient to rely

// on loweredFirstWord. This is because they are not statements

// in the grammar and we are relying on Preview to parse them.

// For instance, we don't want: "BEGIN JUNK" to be parsed

// as StmtBegin.

trimmedNoComments, _ := SplitTrailingComments(trimmed)

switch strings.ToLower(trimmedNoComments) {

case "begin", "start transaction":

return StmtBegin

case "commit":

return StmtCommit

case "rollback":

return StmtRollback

}

switch loweredFirstWord {

case "create", "alter", "rename", "drop", "truncate":

return StmtDDL

case "set":

return StmtSet

case "show":

return StmtShow

case "use":

return StmtUse

case "analyze", "describe", "desc", "explain", "repair", "optimize":

return StmtOther

}

if strings.Index(trimmed, "/*!") == 0 {

return StmtComment

}

return StmtUnknown

}

// StmtType returns the statement type as a string

func StmtType(stmtType int) string {

switch stmtType {

case StmtSelect:

return "SELECT"

case StmtStream:

return "STREAM"

case StmtInsert:

return "INSERT"

case StmtReplace:

return "REPLACE"

case StmtUpdate:

return "UPDATE"

case StmtDelete:

return "DELETE"

case StmtDDL:

return "DDL"

case StmtBegin:

return "BEGIN"

case StmtCommit:

return "COMMIT"

case StmtRollback:

return "ROLLBACK"

case StmtSet:

return "SET"

case StmtShow:

return "SHOW"

case StmtUse:

return "USE"

case StmtOther:

return "OTHER"

default:

return "UNKNOWN"

}

// IsDML returns true if the query is an INSERT, UPDATE or DELETE statement.

func IsDML(sql string) bool {

switch Preview(sql) {

case StmtInsert, StmtReplace, StmtUpdate, StmtDelete:

return true

}

return false

}

// GetTableName returns the table name from the SimpleTableExpr

// only if it's a simple expression. Otherwise, it returns "".

func GetTableName(node SimpleTableExpr) TableIdent {

if n, ok := node.(TableName); ok && n.Qualifier.IsEmpty() {

return n.Name

}

// sub-select or '.' expression

return NewTableIdent("")

}

// IsColName returns true if the Expr is a *ColName.

func IsColName(node Expr) bool {

_, ok := node.(*ColName)

return ok

}

// IsValue returns true if the Expr is a string, integral or value arg.

// NULL is not considered to be a value.

func IsValue(node Expr) bool {

switch v := node.(type) {

case *SQLVal:

switch v.Type {

case StrVal, HexVal, IntVal, ValArg:

return true

}

return false

}

// IsNull returns true if the Expr is SQL NULL

func IsNull(node Expr) bool {

switch node.(type) {

case *NullVal:

return true

}

return false

}

// IsSimpleTuple returns true if the Expr is a ValTuple that

// contains simple values or if it's a list arg.

func IsSimpleTuple(node Expr) bool {

switch vals := node.(type) {

case ValTuple:

for _, n := range vals {

if !IsValue(n) {

return false

}

return true

case ListArg:

return true

}

// It's a subquery

return false

}

// NewPlanValue builds a sqltypes.PlanValue from an Expr.

func NewPlanValue(node Expr) (sqltypes.PlanValue, error) {

switch node := node.(type) {

case *SQLVal:

switch node.Type {

case ValArg:

return sqltypes.PlanValue{Key: string(node.Val[1:])}, nil

case IntVal:

n, err := sqltypes.NewIntegral(string(node.Val))

if err != nil {

return sqltypes.PlanValue{}, vterrors.Errorf(vtrpcpb.Code_INVALID_ARGUMENT, "%v", err)

}

return sqltypes.PlanValue{Value: n}, nil

case StrVal:

return sqltypes.PlanValue{Value: sqltypes.MakeTrusted(sqltypes.VarBinary, node.Val)}, nil

case HexVal:

v, err := node.HexDecode()

if err != nil {

return sqltypes.PlanValue{}, vterrors.Errorf(vtrpcpb.Code_INVALID_ARGUMENT, "%v", err)

}

return sqltypes.PlanValue{Value: sqltypes.MakeTrusted(sqltypes.VarBinary, v)}, nil

}

case ListArg:

return sqltypes.PlanValue{ListKey: string(node[2:])}, nil

case ValTuple:

pv := sqltypes.PlanValue{

Values: make([]sqltypes.PlanValue, 0, len(node)),

}

for _, val := range node {

innerpv, err := NewPlanValue(val)

if err != nil {

return sqltypes.PlanValue{}, err

}

if innerpv.ListKey != "" || innerpv.Values != nil {

return sqltypes.PlanValue{}, vterrors.New(vtrpcpb.Code_UNIMPLEMENTED, "unsupported: nested lists")

}

pv.Values = append(pv.Values, innerpv)

}

return pv, nil

case *NullVal:

return sqltypes.PlanValue{}, nil

}

return sqltypes.PlanValue{}, vterrors.Errorf(vtrpcpb.Code_INVALID_ARGUMENT, "expression is too complex '%v'", String(node))

}

// StringIn is a convenience function that returns

// true if str matches any of the values.

func StringIn(str string, values ...string) bool {

for _, val := range values {

if str == val {

return true

}

return false

}

// ExtractSetValues returns a map of key-value pairs

// if the query is a SET statement. Values can be int64 or string.

// Since set variable names are case insensitive, all keys are returned

// as lower case.

func ExtractSetValues(sql string) (keyValues map[string]interface{}, scope string, err error) {

stmt, err := Parse(sql)

if err != nil {

return nil, "", err

}

setStmt, ok := stmt.(*Set)

if !ok {

return nil, "", fmt.Errorf("ast did not yield *sqlparser.Set: %T", stmt)

}

result := make(map[string]interface{})

for _, expr := range setStmt.Exprs {

key := expr.Name.Lowered()

switch expr := expr.Expr.(type) {

case *SQLVal:

switch expr.Type {

case StrVal:

result[key] = string(expr.Val)

case IntVal:

num, err := strconv.ParseInt(string(expr.Val), 0, 64)

if err != nil {

return nil, "", err

}

result[key] = num

default:

return nil, "", fmt.Errorf("invalid value type: %v", String(expr))

}

case *NullVal:

result[key] = nil

case *Default:

result[key] = "default"

default:

return nil, "", fmt.Errorf("invalid syntax: %s", String(expr))

}

return result, strings.ToLower(setStmt.Scope), nil

}

sqlparser/analyzer.go at master · dearcode/sqlparser · GitHub

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