[chore/bugfix] Switch markdown from blackfriday to goldmark (#1267)

Co-authored-by: Autumn! <autumnull@posteo.net>

vendor/github.com/yuin/goldmark/text/segment.go

@@ -0,0 +1,209 @@
+package text
+
+import (
+	"bytes"
+	"github.com/yuin/goldmark/util"
+)
+
+var space = []byte(" ")
+
+// A Segment struct holds information about source positions.
+type Segment struct {
+	// Start is a start position of the segment.
+	Start int
+
+	// Stop is a stop position of the segment.
+	// This value should be excluded.
+	Stop int
+
+	// Padding is a padding length of the segment.
+	Padding int
+}
+
+// NewSegment return a new Segment.
+func NewSegment(start, stop int) Segment {
+	return Segment{
+		Start:   start,
+		Stop:    stop,
+		Padding: 0,
+	}
+}
+
+// NewSegmentPadding returns a new Segment with the given padding.
+func NewSegmentPadding(start, stop, n int) Segment {
+	return Segment{
+		Start:   start,
+		Stop:    stop,
+		Padding: n,
+	}
+}
+
+// Value returns a value of the segment.
+func (t *Segment) Value(buffer []byte) []byte {
+	if t.Padding == 0 {
+		return buffer[t.Start:t.Stop]
+	}
+	result := make([]byte, 0, t.Padding+t.Stop-t.Start+1)
+	result = append(result, bytes.Repeat(space, t.Padding)...)
+	return append(result, buffer[t.Start:t.Stop]...)
+}
+
+// Len returns a length of the segment.
+func (t *Segment) Len() int {
+	return t.Stop - t.Start + t.Padding
+}
+
+// Between returns a segment between this segment and the given segment.
+func (t *Segment) Between(other Segment) Segment {
+	if t.Stop != other.Stop {
+		panic("invalid state")
+	}
+	return NewSegmentPadding(
+		t.Start,
+		other.Start,
+		t.Padding-other.Padding,
+	)
+}
+
+// IsEmpty returns true if this segment is empty, otherwise false.
+func (t *Segment) IsEmpty() bool {
+	return t.Start >= t.Stop && t.Padding == 0
+}
+
+// TrimRightSpace returns a new segment by slicing off all trailing
+// space characters.
+func (t *Segment) TrimRightSpace(buffer []byte) Segment {
+	v := buffer[t.Start:t.Stop]
+	l := util.TrimRightSpaceLength(v)
+	if l == len(v) {
+		return NewSegment(t.Start, t.Start)
+	}
+	return NewSegmentPadding(t.Start, t.Stop-l, t.Padding)
+}
+
+// TrimLeftSpace returns a new segment by slicing off all leading
+// space characters including padding.
+func (t *Segment) TrimLeftSpace(buffer []byte) Segment {
+	v := buffer[t.Start:t.Stop]
+	l := util.TrimLeftSpaceLength(v)
+	return NewSegment(t.Start+l, t.Stop)
+}
+
+// TrimLeftSpaceWidth returns a new segment by slicing off leading space
+// characters until the given width.
+func (t *Segment) TrimLeftSpaceWidth(width int, buffer []byte) Segment {
+	padding := t.Padding
+	for ; width > 0; width-- {
+		if padding == 0 {
+			break
+		}
+		padding--
+	}
+	if width == 0 {
+		return NewSegmentPadding(t.Start, t.Stop, padding)
+	}
+	text := buffer[t.Start:t.Stop]
+	start := t.Start
+	for _, c := range text {
+		if start >= t.Stop-1 || width <= 0 {
+			break
+		}
+		if c == ' ' {
+			width--
+		} else if c == '\t' {
+			width -= 4
+		} else {
+			break
+		}
+		start++
+	}
+	if width < 0 {
+		padding = width * -1
+	}
+	return NewSegmentPadding(start, t.Stop, padding)
+}
+
+// WithStart returns a new Segment with same value except Start.
+func (t *Segment) WithStart(v int) Segment {
+	return NewSegmentPadding(v, t.Stop, t.Padding)
+}
+
+// WithStop returns a new Segment with same value except Stop.
+func (t *Segment) WithStop(v int) Segment {
+	return NewSegmentPadding(t.Start, v, t.Padding)
+}
+
+// ConcatPadding concats the padding to the given slice.
+func (t *Segment) ConcatPadding(v []byte) []byte {
+	if t.Padding > 0 {
+		return append(v, bytes.Repeat(space, t.Padding)...)
+	}
+	return v
+}
+
+// Segments is a collection of the Segment.
+type Segments struct {
+	values []Segment
+}
+
+// NewSegments return a new Segments.
+func NewSegments() *Segments {
+	return &Segments{
+		values: nil,
+	}
+}
+
+// Append appends the given segment after the tail of the collection.
+func (s *Segments) Append(t Segment) {
+	if s.values == nil {
+		s.values = make([]Segment, 0, 20)
+	}
+	s.values = append(s.values, t)
+}
+
+// AppendAll appends all elements of given segments after the tail of the collection.
+func (s *Segments) AppendAll(t []Segment) {
+	if s.values == nil {
+		s.values = make([]Segment, 0, 20)
+	}
+	s.values = append(s.values, t...)
+}
+
+// Len returns the length of the collection.
+func (s *Segments) Len() int {
+	if s.values == nil {
+		return 0
+	}
+	return len(s.values)
+}
+
+// At returns a segment at the given index.
+func (s *Segments) At(i int) Segment {
+	return s.values[i]
+}
+
+// Set sets the given Segment.
+func (s *Segments) Set(i int, v Segment) {
+	s.values[i] = v
+}
+
+// SetSliced replace the collection with a subsliced value.
+func (s *Segments) SetSliced(lo, hi int) {
+	s.values = s.values[lo:hi]
+}
+
+// Sliced returns a subslice of the collection.
+func (s *Segments) Sliced(lo, hi int) []Segment {
+	return s.values[lo:hi]
+}
+
+// Clear delete all element of the collection.
+func (s *Segments) Clear() {
+	s.values = nil
+}
+
+// Unshift insert the given Segment to head of the collection.
+func (s *Segments) Unshift(v Segment) {
+	s.values = append(s.values[0:1], s.values[0:]...)
+	s.values[0] = v
+}