OP#792 initial commit after fork

internal/s3select/progress.go

@@ -0,0 +1,171 @@
+// Copyright (c) 2015-2021 MinIO, Inc.
+//
+// This file is part of MinIO Object Storage stack
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package s3select
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"io"
+	"runtime"
+	"sync"
+	"sync/atomic"
+
+	"github.com/cosnicolaou/pbzip2"
+	"github.com/klauspost/compress/s2"
+	"github.com/klauspost/compress/zstd"
+	gzip "github.com/klauspost/pgzip"
+	"github.com/pierrec/lz4/v4"
+)
+
+type countUpReader struct {
+	reader    io.Reader
+	bytesRead int64
+}
+
+// Max bzip2 concurrency across calls. 50% of GOMAXPROCS.
+var bz2Limiter = pbzip2.CreateConcurrencyPool((runtime.GOMAXPROCS(0) + 1) / 2)
+
+func (r *countUpReader) Read(p []byte) (n int, err error) {
+	n, err = r.reader.Read(p)
+	atomic.AddInt64(&r.bytesRead, int64(n))
+	return n, err
+}
+
+func (r *countUpReader) BytesRead() int64 {
+	if r == nil {
+		return 0
+	}
+	return atomic.LoadInt64(&r.bytesRead)
+}
+
+func newCountUpReader(reader io.Reader) *countUpReader {
+	return &countUpReader{
+		reader: reader,
+	}
+}
+
+type progressReader struct {
+	rc              io.ReadCloser
+	scannedReader   *countUpReader
+	processedReader *countUpReader
+
+	closedMu sync.Mutex
+	closer   io.ReadCloser
+	closed   bool
+}
+
+func (pr *progressReader) Read(p []byte) (n int, err error) {
+	// This ensures that Close will block until Read has completed.
+	// This allows another goroutine to close the reader.
+	pr.closedMu.Lock()
+	defer pr.closedMu.Unlock()
+	if pr.closed {
+		return 0, errors.New("progressReader: read after Close")
+	}
+	return pr.processedReader.Read(p)
+}
+
+func (pr *progressReader) Close() error {
+	pr.closedMu.Lock()
+	defer pr.closedMu.Unlock()
+	if pr.closed {
+		return nil
+	}
+	pr.closed = true
+	if pr.closer != nil {
+		pr.closer.Close()
+	}
+	return pr.rc.Close()
+}
+
+func (pr *progressReader) Stats() (bytesScanned, bytesProcessed int64) {
+	if pr == nil {
+		return 0, 0
+	}
+	return pr.scannedReader.BytesRead(), pr.processedReader.BytesRead()
+}
+
+func newProgressReader(rc io.ReadCloser, compType CompressionType) (*progressReader, error) {
+	if rc == nil {
+		return nil, errors.New("newProgressReader: nil reader provided")
+	}
+	scannedReader := newCountUpReader(rc)
+	pr := progressReader{
+		rc:            rc,
+		scannedReader: scannedReader,
+	}
+	var r io.Reader
+
+	switch compType {
+	case noneType:
+		r = scannedReader
+	case gzipType:
+		gzr, err := gzip.NewReader(scannedReader)
+		if err != nil {
+			if errors.Is(err, gzip.ErrHeader) || errors.Is(err, gzip.ErrChecksum) {
+				return nil, errInvalidCompression(err, compType)
+			}
+			return nil, errTruncatedInput(err)
+		}
+		r = gzr
+		pr.closer = gzr
+	case bzip2Type:
+		ctx, cancel := context.WithCancel(context.Background())
+		r = pbzip2.NewReader(ctx, scannedReader, pbzip2.DecompressionOptions(
+			pbzip2.BZConcurrency((runtime.GOMAXPROCS(0)+1)/2),
+			pbzip2.BZConcurrencyPool(bz2Limiter),
+		))
+		pr.closer = &nopReadCloser{fn: cancel}
+	case zstdType:
+		// Set a max window of 64MB. More than reasonable.
+		zr, err := zstd.NewReader(scannedReader, zstd.WithDecoderConcurrency(2), zstd.WithDecoderMaxWindow(64<<20))
+		if err != nil {
+			return nil, errInvalidCompression(err, compType)
+		}
+		r = zr
+		pr.closer = zr.IOReadCloser()
+	case lz4Type:
+		r = lz4.NewReader(scannedReader)
+	case s2Type:
+		r = s2.NewReader(scannedReader)
+	case snappyType:
+		r = s2.NewReader(scannedReader, s2.ReaderMaxBlockSize(64<<10))
+	default:
+		return nil, errInvalidCompressionFormat(fmt.Errorf("unknown compression type '%v'", compType))
+	}
+	pr.processedReader = newCountUpReader(r)
+
+	return &pr, nil
+}
+
+type nopReadCloser struct {
+	fn func()
+}
+
+func (n2 *nopReadCloser) Read(p []byte) (n int, err error) {
+	panic("should not be called")
+}
+
+func (n2 *nopReadCloser) Close() error {
+	if n2.fn != nil {
+		n2.fn()
+	}
+	n2.fn = nil
+	return nil
+}