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88 lines
2.3 KiB
88 lines
2.3 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 json
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import (
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"io"
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"github.com/minio/minio/pkg/s3select/sql"
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"github.com/bcicen/jstream"
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)
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// Reader - JSON record reader for S3Select.
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type Reader struct {
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args *ReaderArgs
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decoder *jstream.Decoder
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valueCh chan *jstream.MetaValue
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readCloser io.ReadCloser
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}
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// Read - reads single record.
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func (r *Reader) Read(dst sql.Record) (sql.Record, error) {
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v, ok := <-r.valueCh
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if !ok {
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if err := r.decoder.Err(); err != nil {
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return nil, errJSONParsingError(err)
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}
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return nil, io.EOF
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}
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var kvs jstream.KVS
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if v.ValueType == jstream.Object {
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// This is a JSON object type (that preserves key
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// order)
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kvs = v.Value.(jstream.KVS)
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} else {
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// To be AWS S3 compatible Select for JSON needs to
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// output non-object JSON as single column value
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// i.e. a map with `_1` as key and value as the
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// non-object.
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kvs = jstream.KVS{jstream.KV{Key: "_1", Value: v.Value}}
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}
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dstRec, ok := dst.(*Record)
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if !ok {
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dstRec = &Record{}
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}
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dstRec.KVS = kvs
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dstRec.SelectFormat = sql.SelectFmtJSON
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return dstRec, nil
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}
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// Close - closes underlying reader.
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func (r *Reader) Close() error {
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// Close the input.
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// Potentially racy if the stream decoder is still reading.
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err := r.readCloser.Close()
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for range r.valueCh {
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// Drain values so we don't leak a goroutine.
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// Since we have closed the input, it should fail rather quickly.
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}
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return err
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}
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// NewReader - creates new JSON reader using readCloser.
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func NewReader(readCloser io.ReadCloser, args *ReaderArgs) *Reader {
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d := jstream.NewDecoder(readCloser, 0).ObjectAsKVS()
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return &Reader{
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args: args,
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decoder: d,
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valueCh: d.Stream(),
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readCloser: readCloser,
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}
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}
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