audio: skip seeking only when the error is ErrUnsupported

Updates #3193

audio/internal/convert/float32.go

@@ -15,6 +15,7 @@
 package convert
 
 import (
+	"errors"
 	"fmt"
 	"io"
 	"math"
@@ -83,7 +84,7 @@ func (r *float32BytesReader) Read(buf []byte) (int, error) {
 func (r *float32BytesReader) Seek(offset int64, whence int) (int64, error) {
 	s, ok := r.r.(io.Seeker)
 	if !ok {
-		return 0, fmt.Errorf("float32: the source must be io.Seeker when seeking but not")
+		return 0, fmt.Errorf("float32: the source must be io.Seeker when seeking but not: %w", errors.ErrUnsupported)
 	}
 	r.i16Buf = r.i16Buf[:0]
 	r.eof = false

audio/internal/convert/resampling.go

@@ -15,6 +15,7 @@
 package convert
 
 import (
+	"errors"
 	"fmt"
 	"io"
 	"math"
@@ -307,7 +308,7 @@ func (r *Resampling) Read(b []byte) (int, error) {
 
 func (r *Resampling) Seek(offset int64, whence int) (int64, error) {
 	if _, ok := r.source.(io.Seeker); !ok {
-		return 0, fmt.Errorf("convert: source must be io.Seeker")
+		return 0, fmt.Errorf("convert: source must be io.Seeker: %w", errors.ErrUnsupported)
 	}
 
 	r.eof = false

audio/player.go

@@ -15,6 +15,7 @@
 package audio
 
 import (
+	"errors"
 	"io"
 	"runtime"
 	"sync"
@@ -408,6 +409,9 @@ func newTimeStream(r io.Reader, seekable bool, sampleRate int, bitDepthInBytes i
 		// Get the current position of the source.
 		pos, err := s.r.(io.Seeker).Seek(0, io.SeekCurrent)
 		if err != nil {
+			if !errors.Is(err, errors.ErrUnsupported) {
+				return nil, err
+			}
 			// Ignore the error, as the undelrying source might not support Seek (#3192).
 			// This happens when vorbis.Decode* is used, as vorbis.Stream is io.Seeker whichever the underlying source is.
 			pos = 0

audio/vorbis/float32.go

@@ -15,6 +15,8 @@
 package vorbis
 
 import (
+	"errors"
+	"fmt"
 	"io"
 	"math"
 
@@ -23,12 +25,16 @@ import (
 
 var _ io.ReadSeeker = (*float32BytesReadSeeker)(nil)
 
-func newFloat32BytesReadSeeker(r *oggvorbis.Reader) *float32BytesReadSeeker {
-	return &float32BytesReadSeeker{r: r}
+func newFloat32BytesReadSeeker(r *oggvorbis.Reader, seekable bool) *float32BytesReadSeeker {
+	return &float32BytesReadSeeker{
+		r:        r,
+		seekable: seekable,
+	}
 }
 
 type float32BytesReadSeeker struct {
 	r        *oggvorbis.Reader
+	seekable bool
 	fbuf     []float32
 	pos      int64
 }
@@ -62,6 +68,10 @@ func (r *float32BytesReadSeeker) Read(buf []byte) (int, error) {
 }
 
 func (r *float32BytesReadSeeker) Seek(offset int64, whence int) (int64, error) {
+	if !r.seekable {
+		return 0, fmt.Errorf("vorbis: the source must be io.Seeker but not: %w", errors.ErrUnsupported)
+	}
+
 	sampleSize := int64(r.r.Channels()) * 4
 	offset = offset / sampleSize * sampleSize
 

audio/vorbis/vorbis.go

@@ -16,6 +16,7 @@
 package vorbis
 
 import (
+	"errors"
 	"fmt"
 	"io"
 
@@ -78,7 +79,8 @@ func DecodeF32(src io.Reader) (*Stream, error) {
 		return nil, fmt.Errorf("vorbis: number of channels must be 1 or 2 but was %d", r.Channels())
 	}
 
-	var s io.ReadSeeker = newFloat32BytesReadSeeker(r)
+	_, seekable := src.(io.Seeker)
+	var s io.ReadSeeker = newFloat32BytesReadSeeker(r, seekable)
 	length := r.Length() * int64(r.Channels()) * bitDepthInBytesFloat32
 	if r.Channels() == 1 {
 		s = convert.NewStereoF32(s, true)
@@ -91,7 +93,7 @@ func DecodeF32(src io.Reader) (*Stream, error) {
 		sampleRate: r.SampleRate(),
 	}
 	// Read some data for performance (#297).
-	if _, ok := src.(io.Seeker); ok {
+	if seekable {
 		if _, err := stream.Read(make([]byte, 65536)); err != nil && err != io.EOF {
 			return nil, err
 		}
@@ -104,6 +106,7 @@ func DecodeF32(src io.Reader) (*Stream, error) {
 
 type i16Stream struct {
 	posInBytes   int64
+	seekable     bool
 	vorbisReader *oggvorbis.Reader
 	i16Reader    io.Reader
 }
@@ -128,6 +131,10 @@ retry:
 }
 
 func (s *i16Stream) Seek(offset int64, whence int) (int64, error) {
+	if !s.seekable {
+		return 0, fmt.Errorf("vorbis: the source must be io.Seeker but not: %w", errors.ErrUnsupported)
+	}
+
 	next := int64(0)
 	switch whence {
 	case io.SeekStart:
@@ -162,12 +169,14 @@ func decodeI16(in io.Reader) (*i16Stream, error) {
 		return nil, fmt.Errorf("vorbis: number of channels must be 1 or 2 but was %d", r.Channels())
 	}
 
+	_, seekable := in.(io.Seeker)
 	s := &i16Stream{
+		seekable:     seekable,
 		posInBytes:   0,
 		vorbisReader: r,
 	}
 	// Read some data for performance (#297).
-	if _, ok := in.(io.Seeker); ok {
+	if seekable {
 		if _, err := s.Read(make([]byte, 65536)); err != nil && err != io.EOF {
 			return nil, err
 		}