mu sync.Mutex
}

func (pr *syncReadCloser) 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.mu.Lock()
	defer pr.mu.Unlock()
	if pr.rc == nil {
		return 0, io.EOF
	}
	return pr.rc.Read(p)
}

func (pr *syncReadCloser) Close() error {
	pr.mu.Lock()
	defer pr.mu.Unlock()
	if pr.rc != nil {

func NewParquetReader(rsc io.ReadSeekCloser, _ *ReaderArgs) (r *Reader, err error) {
	fr, err := parquetgo.NewFileReader(rsc)
	if err != nil {
		return nil, errParquetParsingError(err)
	}

	return &Reader{Closer: rsc, r: fr}, nil
}

func (pr *Reader) Read(dst sql.Record) (rec sql.Record, rerr error) {
	nextRow, err := pr.r.NextRow()
	if err != nil {
		if err == io.EOF {
			return nil, err
		}

// On errors, r.err will be set. This should only be accessed after r.decoded has been closed.
func (r *Reader) startReader() {
	defer r.onReaderExit()
	var tmpObj simdjson.Object
	for {
		var in simdjson.Stream
		select {
		case in = <-r.input:
		case <-r.exitReader:
			return
		}
		if in.Error != nil && in.Error != io.EOF {
			r.err = &in.Error
			return
		}
		if in.Value == nil {

func (r *Reader) ETag() ETag {
	sum := r.md5.Sum(nil)
	return ETag(sum)
}

// VerifyError is an error signaling that a
// computed ETag does not match an expected
// ETag.
type VerifyError struct {
	Expected ETag
	Computed ETag
}

func (v VerifyError) Error() string {
	return fmt.Sprintf("etag: expected ETag %q does not match computed ETag %q", v.Expected, v.Computed)
}

	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 newReader(ctx, src, size, md5Hex, sha256Hex, actualSize, false, nil)
}

func newReader(ctx context.Context, src io.Reader, size int64, md5Hex, sha256Hex string, actualSize int64, disableMD5 bool, forceMD5 []byte) (*Reader, error) {
	MD5, err := hex.DecodeString(md5Hex)
	if err != nil {

// MonitoredReader represents a throttled reader subject to bandwidth monitoring
type MonitoredReader struct {
	r        io.Reader
	throttle *bucketThrottle
	ctx      context.Context // request context
	lastErr  error           // last error reported, if this non-nil all reads will fail.
	m        *Monitor
	opts     *MonitorReaderOptions
}

// BucketOptions represents the bucket and optionally its replication target pair.