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120 lines
3.3 KiB
Go
120 lines
3.3 KiB
Go
/*
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Copyright 2017 Google Inc.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package sqlparser
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import (
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"bytes"
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"fmt"
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"github.com/xwb1989/sqlparser/dependency/querypb"
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"github.com/xwb1989/sqlparser/dependency/sqltypes"
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)
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// ParsedQuery represents a parsed query where
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// bind locations are precompued for fast substitutions.
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type ParsedQuery struct {
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Query string
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bindLocations []bindLocation
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}
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type bindLocation struct {
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offset, length int
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}
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// NewParsedQuery returns a ParsedQuery of the ast.
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func NewParsedQuery(node SQLNode) *ParsedQuery {
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buf := NewTrackedBuffer(nil)
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buf.Myprintf("%v", node)
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return buf.ParsedQuery()
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}
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// GenerateQuery generates a query by substituting the specified
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// bindVariables. The extras parameter specifies special parameters
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// that can perform custom encoding.
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func (pq *ParsedQuery) GenerateQuery(bindVariables map[string]*querypb.BindVariable, extras map[string]Encodable) ([]byte, error) {
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if len(pq.bindLocations) == 0 {
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return []byte(pq.Query), nil
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}
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buf := bytes.NewBuffer(make([]byte, 0, len(pq.Query)))
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current := 0
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for _, loc := range pq.bindLocations {
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buf.WriteString(pq.Query[current:loc.offset])
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name := pq.Query[loc.offset : loc.offset+loc.length]
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if encodable, ok := extras[name[1:]]; ok {
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encodable.EncodeSQL(buf)
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} else {
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supplied, _, err := FetchBindVar(name, bindVariables)
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if err != nil {
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return nil, err
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}
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EncodeValue(buf, supplied)
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}
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current = loc.offset + loc.length
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}
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buf.WriteString(pq.Query[current:])
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return buf.Bytes(), nil
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}
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// EncodeValue encodes one bind variable value into the query.
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func EncodeValue(buf *bytes.Buffer, value *querypb.BindVariable) {
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if value.Type != querypb.Type_TUPLE {
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// Since we already check for TUPLE, we don't expect an error.
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v, _ := sqltypes.BindVariableToValue(value)
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v.EncodeSQL(buf)
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return
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}
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// It's a TUPLE.
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buf.WriteByte('(')
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for i, bv := range value.Values {
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if i != 0 {
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buf.WriteString(", ")
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}
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sqltypes.ProtoToValue(bv).EncodeSQL(buf)
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}
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buf.WriteByte(')')
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}
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// FetchBindVar resolves the bind variable by fetching it from bindVariables.
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func FetchBindVar(name string, bindVariables map[string]*querypb.BindVariable) (val *querypb.BindVariable, isList bool, err error) {
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name = name[1:]
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if name[0] == ':' {
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name = name[1:]
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isList = true
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}
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supplied, ok := bindVariables[name]
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if !ok {
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return nil, false, fmt.Errorf("missing bind var %s", name)
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}
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if isList {
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if supplied.Type != querypb.Type_TUPLE {
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return nil, false, fmt.Errorf("unexpected list arg type (%v) for key %s", supplied.Type, name)
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}
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if len(supplied.Values) == 0 {
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return nil, false, fmt.Errorf("empty list supplied for %s", name)
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}
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return supplied, true, nil
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}
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if supplied.Type == querypb.Type_TUPLE {
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return nil, false, fmt.Errorf("unexpected arg type (TUPLE) for non-list key %s", name)
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}
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return supplied, false, nil
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}
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