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128 lines
3.5 KiB
128 lines
3.5 KiB
/*
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* MinIO Cloud Storage, (C) 2019 MinIO, Inc.
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*
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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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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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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 csv
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import (
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"encoding/csv"
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"encoding/json"
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"errors"
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"fmt"
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"io"
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"github.com/bcicen/jstream"
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"github.com/minio/minio/pkg/s3select/sql"
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)
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// Record - is a CSV record.
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type Record struct {
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columnNames []string
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csvRecord []string
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nameIndexMap map[string]int64
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}
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// Get - gets the value for a column name. CSV fields do not have any
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// defined type (other than the default string). So this function
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// always returns fields using sql.FromBytes so that the type
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// specified/implied by the query can be used, or can be automatically
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// converted based on the query.
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func (r *Record) Get(name string) (*sql.Value, error) {
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index, found := r.nameIndexMap[name]
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if !found {
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return nil, fmt.Errorf("column %v not found", name)
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}
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if index >= int64(len(r.csvRecord)) {
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// No value found for column 'name', hence return null
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// value
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return sql.FromNull(), nil
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}
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return sql.FromBytes([]byte(r.csvRecord[index])), nil
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}
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// Set - sets the value for a column name.
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func (r *Record) Set(name string, value *sql.Value) error {
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r.columnNames = append(r.columnNames, name)
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r.csvRecord = append(r.csvRecord, value.CSVString())
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return nil
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}
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// Reset data in record.
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func (r *Record) Reset() {
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if len(r.columnNames) > 0 {
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r.columnNames = r.columnNames[:0]
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}
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if len(r.csvRecord) > 0 {
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r.csvRecord = r.csvRecord[:0]
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}
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for k := range r.nameIndexMap {
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delete(r.nameIndexMap, k)
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}
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}
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// CopyFrom will copy all records from the incoming and append them to the existing records.
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// The source record must be of a similar type.
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// Note that the lookup index is not copied.
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func (r *Record) CopyFrom(record sql.Record) error {
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other, ok := record.(*Record)
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if !ok {
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return fmt.Errorf("unexpected record type, expected %T, got %T", r, record)
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}
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//before := len(r.csvRecord)
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r.columnNames = append(r.columnNames, other.columnNames...)
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r.csvRecord = append(r.csvRecord, other.csvRecord...)
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return nil
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}
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// WriteCSV - encodes to CSV data.
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func (r *Record) WriteCSV(writer io.Writer, fieldDelimiter rune) error {
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w := csv.NewWriter(writer)
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w.Comma = fieldDelimiter
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if err := w.Write(r.csvRecord); err != nil {
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return err
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}
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w.Flush()
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if err := w.Error(); err != nil {
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return err
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}
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return nil
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}
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// WriteJSON - encodes to JSON data.
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func (r *Record) WriteJSON(writer io.Writer) error {
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var kvs jstream.KVS = make([]jstream.KV, len(r.columnNames))
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for i := 0; i < len(r.columnNames); i++ {
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kvs[i] = jstream.KV{Key: r.columnNames[i], Value: r.csvRecord[i]}
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}
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return json.NewEncoder(writer).Encode(kvs)
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}
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// Raw - returns the underlying data with format info.
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func (r *Record) Raw() (sql.SelectObjectFormat, interface{}) {
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return sql.SelectFmtCSV, r
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}
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// Replace - is not supported for CSV
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func (r *Record) Replace(_ jstream.KVS) error {
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return errors.New("Replace is not supported for CSV")
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}
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// NewRecord - creates new CSV record.
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func NewRecord() *Record {
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return &Record{}
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}
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