1 files changed, 242 insertions, 0 deletions
diff --git a/vendor/github.com/yuin/goldmark/parser/delimiter.go b/vendor/github.com/yuin/goldmark/parser/delimiter.go
new file mode 100644
index 0000000000..50aa7bd160
--- /dev/null
+++ b/vendor/github.com/yuin/goldmark/parser/delimiter.go
@@ -0,0 +1,242 @@
+package parser
+
+import (
+	"fmt"
+	"strings"
+	"unicode"
+
+	"github.com/yuin/goldmark/ast"
+	"github.com/yuin/goldmark/text"
+	"github.com/yuin/goldmark/util"
+)
+
+// A DelimiterProcessor interface provides a set of functions about
+// Deliiter nodes.
+type DelimiterProcessor interface {
+	// IsDelimiter returns true if given character is a delimiter, otherwise false.
+	IsDelimiter(byte) bool
+
+	// CanOpenCloser returns true if given opener can close given closer, otherwise false.
+	CanOpenCloser(opener, closer *Delimiter) bool
+
+	// OnMatch will be called when new matched delimiter found.
+	// OnMatch should return a new Node correspond to the matched delimiter.
+	OnMatch(consumes int) ast.Node
+}
+
+// A Delimiter struct represents a delimiter like '*' of the Markdown text.
+type Delimiter struct {
+	ast.BaseInline
+
+	Segment text.Segment
+
+	// CanOpen is set true if this delimiter can open a span for a new node.
+	// See https://spec.commonmark.org/0.29/#can-open-emphasis for details.
+	CanOpen bool
+
+	// CanClose is set true if this delimiter can close a span for a new node.
+	// See https://spec.commonmark.org/0.29/#can-open-emphasis for details.
+	CanClose bool
+
+	// Length is a remaining length of this delmiter.
+	Length int
+
+	// OriginalLength is a original length of this delimiter.
+	OriginalLength int
+
+	// Char is a character of this delimiter.
+	Char byte
+
+	// PreviousDelimiter is a previous sibling delimiter node of this delimiter.
+	PreviousDelimiter *Delimiter
+
+	// NextDelimiter is a next sibling delimiter node of this delimiter.
+	NextDelimiter *Delimiter
+
+	// Processor is a DelimiterProcessor associated with this delimiter.
+	Processor DelimiterProcessor
+}
+
+// Inline implements Inline.Inline.
+func (d *Delimiter) Inline() {}
+
+// Dump implements Node.Dump.
+func (d *Delimiter) Dump(source []byte, level int) {
+	fmt.Printf("%sDelimiter: \"%s\"\n", strings.Repeat("    ", level), string(d.Text(source)))
+}
+
+var kindDelimiter = ast.NewNodeKind("Delimiter")
+
+// Kind implements Node.Kind
+func (d *Delimiter) Kind() ast.NodeKind {
+	return kindDelimiter
+}
+
+// Text implements Node.Text
+func (d *Delimiter) Text(source []byte) []byte {
+	return d.Segment.Value(source)
+}
+
+// ConsumeCharacters consumes delimiters.
+func (d *Delimiter) ConsumeCharacters(n int) {
+	d.Length -= n
+	d.Segment = d.Segment.WithStop(d.Segment.Start + d.Length)
+}
+
+// CalcComsumption calculates how many characters should be used for opening
+// a new span correspond to given closer.
+func (d *Delimiter) CalcComsumption(closer *Delimiter) int {
+	if (d.CanClose || closer.CanOpen) && (d.OriginalLength+closer.OriginalLength)%3 == 0 && closer.OriginalLength%3 != 0 {
+		return 0
+	}
+	if d.Length >= 2 && closer.Length >= 2 {
+		return 2
+	}
+	return 1
+}
+
+// NewDelimiter returns a new Delimiter node.
+func NewDelimiter(canOpen, canClose bool, length int, char byte, processor DelimiterProcessor) *Delimiter {
+	c := &Delimiter{
+		BaseInline:        ast.BaseInline{},
+		CanOpen:           canOpen,
+		CanClose:          canClose,
+		Length:            length,
+		OriginalLength:    length,
+		Char:              char,
+		PreviousDelimiter: nil,
+		NextDelimiter:     nil,
+		Processor:         processor,
+	}
+	return c
+}
+
+// ScanDelimiter scans a delimiter by given DelimiterProcessor.
+func ScanDelimiter(line []byte, before rune, min int, processor DelimiterProcessor) *Delimiter {
+	i := 0
+	c := line[i]
+	j := i
+	if !processor.IsDelimiter(c) {
+		return nil
+	}
+	for ; j < len(line) && c == line[j]; j++ {
+	}
+	if (j - i) >= min {
+		after := rune(' ')
+		if j != len(line) {
+			after = util.ToRune(line, j)
+		}
+
+		canOpen, canClose := false, false
+		beforeIsPunctuation := unicode.IsPunct(before)
+		beforeIsWhitespace := unicode.IsSpace(before)
+		afterIsPunctuation := unicode.IsPunct(after)
+		afterIsWhitespace := unicode.IsSpace(after)
+
+		isLeft := !afterIsWhitespace &&
+			(!afterIsPunctuation || beforeIsWhitespace || beforeIsPunctuation)
+		isRight := !beforeIsWhitespace &&
+			(!beforeIsPunctuation || afterIsWhitespace || afterIsPunctuation)
+
+		if line[i] == '_' {
+			canOpen = isLeft && (!isRight || beforeIsPunctuation)
+			canClose = isRight && (!isLeft || afterIsPunctuation)
+		} else {
+			canOpen = isLeft
+			canClose = isRight
+		}
+		return NewDelimiter(canOpen, canClose, j-i, c, processor)
+	}
+	return nil
+}
+
+// ProcessDelimiters processes the delimiter list in the context.
+// Processing will be stop when reaching the bottom.
+//
+// If you implement an inline parser that can have other inline nodes as
+// children, you should call this function when nesting span has closed.
+func ProcessDelimiters(bottom ast.Node, pc Context) {
+	lastDelimiter := pc.LastDelimiter()
+	if lastDelimiter == nil {
+		return
+	}
+	var closer *Delimiter
+	if bottom != nil {
+		if bottom != lastDelimiter {
+			for c := lastDelimiter.PreviousSibling(); c != nil; {
+				if d, ok := c.(*Delimiter); ok {
+					closer = d
+				}
+				prev := c.PreviousSibling()
+				if prev == bottom {
+					break
+				}
+				c = prev
+			}
+		}
+	} else {
+		closer = pc.FirstDelimiter()
+	}
+	if closer == nil {
+		pc.ClearDelimiters(bottom)
+		return
+	}
+	for closer != nil {
+		if !closer.CanClose {
+			closer = closer.NextDelimiter
+			continue
+		}
+		consume := 0
+		found := false
+		maybeOpener := false
+		var opener *Delimiter
+		for opener = closer.PreviousDelimiter; opener != nil; opener = opener.PreviousDelimiter {
+			if opener.CanOpen && opener.Processor.CanOpenCloser(opener, closer) {
+				maybeOpener = true
+				consume = opener.CalcComsumption(closer)
+				if consume > 0 {
+					found = true
+					break
+				}
+			}
+		}
+		if !found {
+			if !maybeOpener && !closer.CanOpen {
+				pc.RemoveDelimiter(closer)
+			}
+			closer = closer.NextDelimiter
+			continue
+		}
+		opener.ConsumeCharacters(consume)
+		closer.ConsumeCharacters(consume)
+
+		node := opener.Processor.OnMatch(consume)
+
+		parent := opener.Parent()
+		child := opener.NextSibling()
+
+		for child != nil && child != closer {
+			next := child.NextSibling()
+			node.AppendChild(node, child)
+			child = next
+		}
+		parent.InsertAfter(parent, opener, node)
+
+		for c := opener.NextDelimiter; c != nil && c != closer; {
+			next := c.NextDelimiter
+			pc.RemoveDelimiter(c)
+			c = next
+		}
+
+		if opener.Length == 0 {
+			pc.RemoveDelimiter(opener)
+		}
+
+		if closer.Length == 0 {
+			next := closer.NextDelimiter
+			pc.RemoveDelimiter(closer)
+			closer = next
+		}
+	}
+	pc.ClearDelimiters(bottom)
+}