mirror of
https://github.com/minio/minio.git
synced 2024-12-26 23:25:54 -05:00
309 lines
8.2 KiB
Go
309 lines
8.2 KiB
Go
/*
|
|
* MinIO Cloud Storage, (C) 2019 MinIO, Inc.
|
|
*
|
|
* 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 csv
|
|
|
|
import (
|
|
"bufio"
|
|
"bytes"
|
|
"encoding/csv"
|
|
"fmt"
|
|
"io"
|
|
"runtime"
|
|
"sync"
|
|
|
|
"github.com/minio/minio/pkg/s3select/sql"
|
|
)
|
|
|
|
// Reader - CSV record reader for S3Select.
|
|
type Reader struct {
|
|
args *ReaderArgs
|
|
readCloser io.ReadCloser // raw input
|
|
buf *bufio.Reader // input to the splitter
|
|
columnNames []string // names of columns
|
|
nameIndexMap map[string]int64 // name to column index
|
|
current [][]string // current block of results to be returned
|
|
recordsRead int // number of records read in current slice
|
|
input chan *queueItem // input for workers
|
|
queue chan *queueItem // output from workers in order
|
|
err error // global error state, only touched by Reader.Read
|
|
bufferPool sync.Pool // pool of []byte objects for input
|
|
csvDstPool sync.Pool // pool of [][]string used for output
|
|
close chan struct{} // used for shutting down the splitter before end of stream
|
|
readerWg sync.WaitGroup // used to keep track of async reader.
|
|
}
|
|
|
|
// queueItem is an item in the queue.
|
|
type queueItem struct {
|
|
input []byte // raw input sent to the worker
|
|
dst chan [][]string // result of block decode
|
|
err error // any error encountered will be set here
|
|
}
|
|
|
|
// Read - reads single record.
|
|
// Once Read is called the previous record should no longer be referenced.
|
|
func (r *Reader) Read(dst sql.Record) (sql.Record, error) {
|
|
// If we have have any records left, return these before any error.
|
|
for len(r.current) <= r.recordsRead {
|
|
if r.err != nil {
|
|
return nil, r.err
|
|
}
|
|
// Move to next block
|
|
item, ok := <-r.queue
|
|
if !ok {
|
|
r.err = io.EOF
|
|
return nil, r.err
|
|
}
|
|
//lint:ignore SA6002 Using pointer would allocate more since we would have to copy slice header before taking a pointer.
|
|
r.csvDstPool.Put(r.current)
|
|
r.current = <-item.dst
|
|
r.err = item.err
|
|
r.recordsRead = 0
|
|
}
|
|
csvRecord := r.current[r.recordsRead]
|
|
r.recordsRead++
|
|
|
|
// If no column names are set, use _(index)
|
|
if r.columnNames == nil {
|
|
r.columnNames = make([]string, len(csvRecord))
|
|
for i := range csvRecord {
|
|
r.columnNames[i] = fmt.Sprintf("_%v", i+1)
|
|
}
|
|
}
|
|
|
|
// If no index max, add that.
|
|
if r.nameIndexMap == nil {
|
|
r.nameIndexMap = make(map[string]int64)
|
|
for i := range r.columnNames {
|
|
r.nameIndexMap[r.columnNames[i]] = int64(i)
|
|
}
|
|
}
|
|
dstRec, ok := dst.(*Record)
|
|
if !ok {
|
|
dstRec = &Record{}
|
|
}
|
|
dstRec.columnNames = r.columnNames
|
|
dstRec.csvRecord = csvRecord
|
|
dstRec.nameIndexMap = r.nameIndexMap
|
|
|
|
return dstRec, nil
|
|
}
|
|
|
|
// Close - closes underlying reader.
|
|
func (r *Reader) Close() error {
|
|
if r.close != nil {
|
|
close(r.close)
|
|
r.readerWg.Wait()
|
|
r.close = nil
|
|
}
|
|
r.recordsRead = len(r.current)
|
|
if r.err == nil {
|
|
r.err = io.EOF
|
|
}
|
|
return r.readCloser.Close()
|
|
}
|
|
|
|
// nextSplit will attempt to skip a number of bytes and
|
|
// return the buffer until the next newline occurs.
|
|
// The last block will be sent along with an io.EOF.
|
|
func (r *Reader) nextSplit(skip int, dst []byte) ([]byte, error) {
|
|
if cap(dst) < skip {
|
|
dst = make([]byte, 0, skip+1024)
|
|
}
|
|
dst = dst[:skip]
|
|
if skip > 0 {
|
|
n, err := io.ReadFull(r.buf, dst)
|
|
if err != nil && err != io.ErrUnexpectedEOF {
|
|
// If an EOF happens after reading some but not all the bytes,
|
|
// ReadFull returns ErrUnexpectedEOF.
|
|
return dst[:n], err
|
|
}
|
|
dst = dst[:n]
|
|
if err == io.ErrUnexpectedEOF {
|
|
return dst, io.EOF
|
|
}
|
|
}
|
|
// Read until next line.
|
|
in, err := r.buf.ReadBytes('\n')
|
|
dst = append(dst, in...)
|
|
return dst, err
|
|
}
|
|
|
|
// csvSplitSize is the size of each block.
|
|
// Blocks will read this much and find the first following newline.
|
|
// 128KB appears to be a very reasonable default.
|
|
const csvSplitSize = 128 << 10
|
|
|
|
// startReaders will read the header if needed and spin up a parser
|
|
// and a number of workers based on GOMAXPROCS.
|
|
// If an error is returned no goroutines have been started and r.err will have been set.
|
|
func (r *Reader) startReaders(newReader func(io.Reader) *csv.Reader) error {
|
|
if r.args.FileHeaderInfo != none {
|
|
// Read column names
|
|
// Get one line.
|
|
b, err := r.nextSplit(0, nil)
|
|
if err != nil {
|
|
r.err = err
|
|
return err
|
|
}
|
|
reader := newReader(bytes.NewReader(b))
|
|
record, err := reader.Read()
|
|
if err != nil {
|
|
r.err = err
|
|
if err != io.EOF {
|
|
r.err = errCSVParsingError(err)
|
|
return errCSVParsingError(err)
|
|
}
|
|
return err
|
|
}
|
|
|
|
if r.args.FileHeaderInfo == use {
|
|
// Copy column names since records will be reused.
|
|
columns := append(make([]string, 0, len(record)), record...)
|
|
r.columnNames = columns
|
|
}
|
|
}
|
|
|
|
r.bufferPool.New = func() interface{} {
|
|
return make([]byte, csvSplitSize+1024)
|
|
}
|
|
|
|
// Create queue
|
|
r.queue = make(chan *queueItem, runtime.GOMAXPROCS(0))
|
|
r.input = make(chan *queueItem, runtime.GOMAXPROCS(0))
|
|
r.readerWg.Add(1)
|
|
|
|
// Start splitter
|
|
go func() {
|
|
defer close(r.input)
|
|
defer close(r.queue)
|
|
defer r.readerWg.Done()
|
|
for {
|
|
next, err := r.nextSplit(csvSplitSize, r.bufferPool.Get().([]byte))
|
|
q := queueItem{
|
|
input: next,
|
|
dst: make(chan [][]string, 1),
|
|
err: err,
|
|
}
|
|
select {
|
|
case <-r.close:
|
|
return
|
|
case r.queue <- &q:
|
|
}
|
|
|
|
select {
|
|
case <-r.close:
|
|
return
|
|
case r.input <- &q:
|
|
}
|
|
if err != nil {
|
|
// Exit on any error.
|
|
return
|
|
}
|
|
}
|
|
}()
|
|
|
|
// Start parsers
|
|
for i := 0; i < runtime.GOMAXPROCS(0); i++ {
|
|
go func() {
|
|
for in := range r.input {
|
|
if len(in.input) == 0 {
|
|
in.dst <- nil
|
|
continue
|
|
}
|
|
dst, ok := r.csvDstPool.Get().([][]string)
|
|
if !ok {
|
|
dst = make([][]string, 0, 1000)
|
|
}
|
|
|
|
cr := newReader(bytes.NewBuffer(in.input))
|
|
all := dst[:0]
|
|
err := func() error {
|
|
// Read all records until EOF or another error.
|
|
for {
|
|
record, err := cr.Read()
|
|
if err == io.EOF {
|
|
return nil
|
|
}
|
|
if err != nil {
|
|
return errCSVParsingError(err)
|
|
}
|
|
var recDst []string
|
|
if len(dst) > len(all) {
|
|
recDst = dst[len(all)]
|
|
}
|
|
if cap(recDst) < len(record) {
|
|
recDst = make([]string, len(record))
|
|
}
|
|
recDst = recDst[:len(record)]
|
|
copy(recDst, record)
|
|
all = append(all, recDst)
|
|
}
|
|
}()
|
|
if err != nil {
|
|
in.err = err
|
|
}
|
|
// We don't need the input any more.
|
|
//lint:ignore SA6002 Using pointer would allocate more since we would have to copy slice header before taking a pointer.
|
|
r.bufferPool.Put(in.input)
|
|
in.input = nil
|
|
in.dst <- all
|
|
}
|
|
}()
|
|
}
|
|
return nil
|
|
|
|
}
|
|
|
|
// NewReader - creates new CSV reader using readCloser.
|
|
func NewReader(readCloser io.ReadCloser, args *ReaderArgs) (*Reader, error) {
|
|
if args == nil || args.IsEmpty() {
|
|
panic(fmt.Errorf("empty args passed %v", args))
|
|
}
|
|
csvIn := io.Reader(readCloser)
|
|
if args.RecordDelimiter != "\n" {
|
|
csvIn = &recordTransform{
|
|
reader: readCloser,
|
|
recordDelimiter: []byte(args.RecordDelimiter),
|
|
oneByte: make([]byte, len(args.RecordDelimiter)-1),
|
|
}
|
|
}
|
|
|
|
r := &Reader{
|
|
args: args,
|
|
buf: bufio.NewReaderSize(csvIn, csvSplitSize*2),
|
|
readCloser: readCloser,
|
|
close: make(chan struct{}),
|
|
}
|
|
|
|
// Assume args are validated by ReaderArgs.UnmarshalXML()
|
|
newCsvReader := func(r io.Reader) *csv.Reader {
|
|
ret := csv.NewReader(r)
|
|
ret.Comma = []rune(args.FieldDelimiter)[0]
|
|
ret.Comment = []rune(args.CommentCharacter)[0]
|
|
ret.FieldsPerRecord = -1
|
|
// If LazyQuotes is true, a quote may appear in an unquoted field and a
|
|
// non-doubled quote may appear in a quoted field.
|
|
ret.LazyQuotes = true
|
|
// We do not trim leading space to keep consistent with s3.
|
|
ret.TrimLeadingSpace = false
|
|
ret.ReuseRecord = true
|
|
return ret
|
|
}
|
|
|
|
return r, r.startReaders(newCsvReader)
|
|
}
|