update CustomDecoder.Segment to CustomDecoder.SegmentTag

example/template/custom-playlist-tag-template.go

@@ -29,7 +29,7 @@ func (tag *CustomPlaylistTag) Decode(line string) (m3u8.CustomTag, error) {
 }
 
 // This is a playlist tag example
-func (tag *CustomPlaylistTag) Segment() bool {
+func (tag *CustomPlaylistTag) SegmentTag() bool {
 	return false
 }
 

example/template/custom-segment-tag-template.go

@@ -48,7 +48,7 @@ func (tag *CustomSegmentTag) Decode(line string) (m3u8.CustomTag, error) {
 }
 
 // This is a playlist tag example
-func (tag *CustomSegmentTag) Segment() bool {
+func (tag *CustomSegmentTag) SegmentTag() bool {
 	return true
 }
 

reader.go

@@ -461,7 +461,7 @@ func decodeLineOfMediaPlaylist(p *MediaPlaylist, wv *WV, state *decodingState, l
 					return err
 				}
 
-				if v.Segment() {
+				if v.SegmentTag() {
 					state.tagCustom = true
 					state.custom[v.TagName()] = t
 				} else {

structure.go

@@ -280,15 +280,27 @@ type Playlist interface {
 
 // Interface for decoding custom and unsupported tags
 type CustomDecoder interface {
+	// TagName should return the full indentifier including the leading '#' as well as the
+	// trailing ':' if the tag also contains a value or attribute list
 	TagName() string
+	// Decode parses a line from the playlist and returns the CustomTag representation
 	Decode(line string) (CustomTag, error)
-	Segment() bool
+	// SegmentTag should return true if this CustomDecoder should apply per segment.
+	// Should returns false if it a MediaPlaylist header tag.
+	// This value is ignored for MasterPlaylists.
+	SegmentTag() bool
 }
 
 // Interface for encoding custom and unsupported tags
 type CustomTag interface {
+	// TagName should return the full indentifier including the leading '#' as well as the
+	// trailing ':' if the tag also contains a value or attribute list
 	TagName() string
+	// Encode should return the complete tag string as a *bytes.Buffer. This will
+	// be used by Playlist.Decode to write the tag to the m3u8.
+	// Return nil to not write anything to the m3u8.
 	Encode() *bytes.Buffer
+	// String should return the encoded tag as a string.
 	String() string
 }
 

structure_test.go

@@ -42,6 +42,10 @@ func (t *MockCustomTag) Decode(line string) (CustomTag, error) {
 }
 
 func (t *MockCustomTag) Encode() *bytes.Buffer {
+	if t.encodedString == "" {
+		return nil
+	}
+
 	buf := new(bytes.Buffer)
 
 	buf.WriteString(t.encodedString)
@@ -53,6 +57,6 @@ func (t *MockCustomTag) String() string {
 	return t.encodedString
 }
 
-func (t *MockCustomTag) Segment() bool {
+func (t *MockCustomTag) SegmentTag() bool {
 	return t.segment
 }

writer.go

@@ -86,7 +86,7 @@ func (p *MasterPlaylist) Encode() *bytes.Buffer {
 	// Write any custom master tags
 	if p.Custom != nil {
 		for _, v := range p.Custom {
-			if customBuf := v.Encode(); customBuf.Len() > 0 {
+			if customBuf := v.Encode(); customBuf != nil {
 				p.buf.WriteString(customBuf.String())
 				p.buf.WriteRune('\n')
 			}
@@ -407,7 +407,7 @@ func (p *MediaPlaylist) Encode() *bytes.Buffer {
 	// Write any custom master tags
 	if p.Custom != nil {
 		for _, v := range p.Custom {
-			if customBuf := v.Encode(); customBuf.Len() > 0 {
+			if customBuf := v.Encode(); customBuf != nil {
 				p.buf.WriteString(customBuf.String())
 				p.buf.WriteRune('\n')
 			}
@@ -670,7 +670,7 @@ func (p *MediaPlaylist) Encode() *bytes.Buffer {
 		// Add Custom Segment Tags here
 		if seg.Custom != nil {
 			for _, v := range seg.Custom {
-				if customBuf := v.Encode(); customBuf.Len() > 0 {
+				if customBuf := v.Encode(); customBuf != nil {
 					p.buf.WriteString(customBuf.String())
 					p.buf.WriteRune('\n')
 				}

writer_test.go

@@ -393,6 +393,12 @@ func TestEncodeMediaPlaylistWithCustomTags(t *testing.T) {
 	}
 	p.SetCustomTag(customPTag)
 
+	customEmptyPTag := &MockCustomTag{
+		name:          "#CustomEmptyPTag",
+		encodedString: "",
+	}
+	p.SetCustomTag(customEmptyPTag)
+
 	e = p.Append("test01.ts", 5.0, "")
 	if e != nil {
 		t.Fatalf("Add 1st segment to a media playlist failed: %s", e)
@@ -407,13 +413,28 @@ func TestEncodeMediaPlaylistWithCustomTags(t *testing.T) {
 		t.Fatalf("Set CustomTag to segment failed: %s", e)
 	}
 
+	customEmptySTag := &MockCustomTag{
+		name:          "#CustomEmptySTag",
+		encodedString: "",
+	}
+	e = p.SetCustomSegmentTag(customEmptySTag)
+	if e != nil {
+		t.Fatalf("Set CustomTag to segment failed: %s", e)
+	}
+
 	encoded := p.String()
 	expectedStrings := []string{"#CustomPTag", "#CustomSTag"}
 	for _, expected := range expectedStrings {
 		if !strings.Contains(encoded, expected) {
 			t.Fatalf("Media playlist does not contain custom tag: %s\nMedia Playlist:\n%v", expected, encoded)
 		}
 	}
+	unexpectedStrings := []string{"#CustomEmptyPTag", "#CustomEmptySTag"}
+	for _, unexpected := range unexpectedStrings {
+		if strings.Contains(encoded, unexpected) {
+			t.Fatalf("Media playlist contains unexpected custom tag: %s\nMedia Playlist:\n%v", unexpected, encoded)
+		}
+	}
 }
 
 // Create new media playlist