forgejo-federation/vendor/github.com/yuin/goldmark/ast/ast.go
zeripath 27757714d0 Change markdown rendering from blackfriday to goldmark (#9533)
* Move to goldmark

Markdown rendering moved from blackfriday to the goldmark.

Multiple subtle changes required to the goldmark extensions to keep
current rendering and defaults.

Can go further with goldmark linkify and have this work within markdown
rendering making the link processor unnecessary.

Need to think about how to go about allowing extensions - at present it
seems that these would be hard to do without recompilation.

* linter fixes

Co-authored-by: Lauris BH <lauris@nix.lv>
2019-12-31 03:53:28 +02:00

485 lines
12 KiB
Go

// Package ast defines AST nodes that represent markdown elements.
package ast
import (
"bytes"
"fmt"
"strings"
textm "github.com/yuin/goldmark/text"
"github.com/yuin/goldmark/util"
)
// A NodeType indicates what type a node belongs to.
type NodeType int
const (
// TypeBlock indicates that a node is kind of block nodes.
TypeBlock NodeType = iota + 1
// TypeInline indicates that a node is kind of inline nodes.
TypeInline
// TypeDocument indicates that a node is kind of document nodes.
TypeDocument
)
// NodeKind indicates more specific type than NodeType.
type NodeKind int
func (k NodeKind) String() string {
return kindNames[k]
}
var kindMax NodeKind
var kindNames = []string{""}
// NewNodeKind returns a new Kind value.
func NewNodeKind(name string) NodeKind {
kindMax++
kindNames = append(kindNames, name)
return kindMax
}
// An Attribute is an attribute of the Node
type Attribute struct {
Name []byte
Value interface{}
}
var attrNameIDS = []byte("#")
var attrNameID = []byte("id")
var attrNameClassS = []byte(".")
var attrNameClass = []byte("class")
// A Node interface defines basic AST node functionalities.
type Node interface {
// Type returns a type of this node.
Type() NodeType
// Kind returns a kind of this node.
Kind() NodeKind
// NextSibling returns a next sibling node of this node.
NextSibling() Node
// PreviousSibling returns a previous sibling node of this node.
PreviousSibling() Node
// Parent returns a parent node of this node.
Parent() Node
// SetParent sets a parent node to this node.
SetParent(Node)
// SetPreviousSibling sets a previous sibling node to this node.
SetPreviousSibling(Node)
// SetNextSibling sets a next sibling node to this node.
SetNextSibling(Node)
// HasChildren returns true if this node has any children, otherwise false.
HasChildren() bool
// ChildCount returns a total number of children.
ChildCount() int
// FirstChild returns a first child of this node.
FirstChild() Node
// LastChild returns a last child of this node.
LastChild() Node
// AppendChild append a node child to the tail of the children.
AppendChild(self, child Node)
// RemoveChild removes a node child from this node.
// If a node child is not children of this node, RemoveChild nothing to do.
RemoveChild(self, child Node)
// RemoveChildren removes all children from this node.
RemoveChildren(self Node)
// SortChildren sorts childrens by comparator.
SortChildren(comparator func(n1, n2 Node) int)
// ReplaceChild replace a node v1 with a node insertee.
// If v1 is not children of this node, ReplaceChild append a insetee to the
// tail of the children.
ReplaceChild(self, v1, insertee Node)
// InsertBefore inserts a node insertee before a node v1.
// If v1 is not children of this node, InsertBefore append a insetee to the
// tail of the children.
InsertBefore(self, v1, insertee Node)
// InsertAfterinserts a node insertee after a node v1.
// If v1 is not children of this node, InsertBefore append a insetee to the
// tail of the children.
InsertAfter(self, v1, insertee Node)
// Dump dumps an AST tree structure to stdout.
// This function completely aimed for debugging.
// level is a indent level. Implementer should indent informations with
// 2 * level spaces.
Dump(source []byte, level int)
// Text returns text values of this node.
Text(source []byte) []byte
// HasBlankPreviousLines returns true if the row before this node is blank,
// otherwise false.
// This method is valid only for block nodes.
HasBlankPreviousLines() bool
// SetBlankPreviousLines sets whether the row before this node is blank.
// This method is valid only for block nodes.
SetBlankPreviousLines(v bool)
// Lines returns text segments that hold positions in a source.
// This method is valid only for block nodes.
Lines() *textm.Segments
// SetLines sets text segments that hold positions in a source.
// This method is valid only for block nodes.
SetLines(*textm.Segments)
// IsRaw returns true if contents should be rendered as 'raw' contents.
IsRaw() bool
// SetAttribute sets the given value to the attributes.
SetAttribute(name []byte, value interface{})
// SetAttributeString sets the given value to the attributes.
SetAttributeString(name string, value interface{})
// Attribute returns a (attribute value, true) if an attribute
// associated with the given name is found, otherwise
// (nil, false)
Attribute(name []byte) (interface{}, bool)
// AttributeString returns a (attribute value, true) if an attribute
// associated with the given name is found, otherwise
// (nil, false)
AttributeString(name string) (interface{}, bool)
// Attributes returns a list of attributes.
// This may be a nil if there are no attributes.
Attributes() []Attribute
// RemoveAttributes removes all attributes from this node.
RemoveAttributes()
}
// A BaseNode struct implements the Node interface.
type BaseNode struct {
firstChild Node
lastChild Node
parent Node
next Node
prev Node
childCount int
attributes []Attribute
}
func ensureIsolated(v Node) {
if p := v.Parent(); p != nil {
p.RemoveChild(p, v)
}
}
// HasChildren implements Node.HasChildren .
func (n *BaseNode) HasChildren() bool {
return n.firstChild != nil
}
// SetPreviousSibling implements Node.SetPreviousSibling .
func (n *BaseNode) SetPreviousSibling(v Node) {
n.prev = v
}
// SetNextSibling implements Node.SetNextSibling .
func (n *BaseNode) SetNextSibling(v Node) {
n.next = v
}
// PreviousSibling implements Node.PreviousSibling .
func (n *BaseNode) PreviousSibling() Node {
return n.prev
}
// NextSibling implements Node.NextSibling .
func (n *BaseNode) NextSibling() Node {
return n.next
}
// RemoveChild implements Node.RemoveChild .
func (n *BaseNode) RemoveChild(self, v Node) {
if v.Parent() != self {
return
}
n.childCount--
prev := v.PreviousSibling()
next := v.NextSibling()
if prev != nil {
prev.SetNextSibling(next)
} else {
n.firstChild = next
}
if next != nil {
next.SetPreviousSibling(prev)
} else {
n.lastChild = prev
}
v.SetParent(nil)
v.SetPreviousSibling(nil)
v.SetNextSibling(nil)
}
// RemoveChildren implements Node.RemoveChildren .
func (n *BaseNode) RemoveChildren(self Node) {
for c := n.firstChild; c != nil; c = c.NextSibling() {
c.SetParent(nil)
c.SetPreviousSibling(nil)
c.SetNextSibling(nil)
}
n.firstChild = nil
n.lastChild = nil
n.childCount = 0
}
// SortChildren implements Node.SortChildren
func (n *BaseNode) SortChildren(comparator func(n1, n2 Node) int) {
var sorted Node
current := n.firstChild
for current != nil {
next := current.NextSibling()
if sorted == nil || comparator(sorted, current) >= 0 {
current.SetNextSibling(sorted)
if sorted != nil {
sorted.SetPreviousSibling(current)
}
sorted = current
sorted.SetPreviousSibling(nil)
} else {
c := sorted
for c.NextSibling() != nil && comparator(c.NextSibling(), current) < 0 {
c = c.NextSibling()
}
current.SetNextSibling(c.NextSibling())
current.SetPreviousSibling(c)
if c.NextSibling() != nil {
c.NextSibling().SetPreviousSibling(current)
}
c.SetNextSibling(current)
}
current = next
}
n.firstChild = sorted
for c := n.firstChild; c != nil; c = c.NextSibling() {
n.lastChild = c
}
}
// FirstChild implements Node.FirstChild .
func (n *BaseNode) FirstChild() Node {
return n.firstChild
}
// LastChild implements Node.LastChild .
func (n *BaseNode) LastChild() Node {
return n.lastChild
}
// ChildCount implements Node.ChildCount .
func (n *BaseNode) ChildCount() int {
return n.childCount
}
// Parent implements Node.Parent .
func (n *BaseNode) Parent() Node {
return n.parent
}
// SetParent implements Node.SetParent .
func (n *BaseNode) SetParent(v Node) {
n.parent = v
}
// AppendChild implements Node.AppendChild .
func (n *BaseNode) AppendChild(self, v Node) {
ensureIsolated(v)
if n.firstChild == nil {
n.firstChild = v
v.SetNextSibling(nil)
v.SetPreviousSibling(nil)
} else {
last := n.lastChild
last.SetNextSibling(v)
v.SetPreviousSibling(last)
}
v.SetParent(self)
n.lastChild = v
n.childCount++
}
// ReplaceChild implements Node.ReplaceChild .
func (n *BaseNode) ReplaceChild(self, v1, insertee Node) {
n.InsertBefore(self, v1, insertee)
n.RemoveChild(self, v1)
}
// InsertAfter implements Node.InsertAfter .
func (n *BaseNode) InsertAfter(self, v1, insertee Node) {
n.InsertBefore(self, v1.NextSibling(), insertee)
}
// InsertBefore implements Node.InsertBefore .
func (n *BaseNode) InsertBefore(self, v1, insertee Node) {
n.childCount++
if v1 == nil {
n.AppendChild(self, insertee)
return
}
ensureIsolated(insertee)
if v1.Parent() == self {
c := v1
prev := c.PreviousSibling()
if prev != nil {
prev.SetNextSibling(insertee)
insertee.SetPreviousSibling(prev)
} else {
n.firstChild = insertee
insertee.SetPreviousSibling(nil)
}
insertee.SetNextSibling(c)
c.SetPreviousSibling(insertee)
insertee.SetParent(self)
}
}
// Text implements Node.Text .
func (n *BaseNode) Text(source []byte) []byte {
var buf bytes.Buffer
for c := n.firstChild; c != nil; c = c.NextSibling() {
buf.Write(c.Text(source))
}
return buf.Bytes()
}
// SetAttribute implements Node.SetAttribute.
func (n *BaseNode) SetAttribute(name []byte, value interface{}) {
if n.attributes == nil {
n.attributes = make([]Attribute, 0, 10)
} else {
for i, a := range n.attributes {
if bytes.Equal(a.Name, name) {
n.attributes[i].Name = name
n.attributes[i].Value = value
return
}
}
}
n.attributes = append(n.attributes, Attribute{name, value})
}
// SetAttributeString implements Node.SetAttributeString
func (n *BaseNode) SetAttributeString(name string, value interface{}) {
n.SetAttribute(util.StringToReadOnlyBytes(name), value)
}
// Attribute implements Node.Attribute.
func (n *BaseNode) Attribute(name []byte) (interface{}, bool) {
if n.attributes == nil {
return nil, false
}
for i, a := range n.attributes {
if bytes.Equal(a.Name, name) {
return n.attributes[i].Value, true
}
}
return nil, false
}
// AttributeString implements Node.AttributeString.
func (n *BaseNode) AttributeString(s string) (interface{}, bool) {
return n.Attribute(util.StringToReadOnlyBytes(s))
}
// Attributes implements Node.Attributes
func (n *BaseNode) Attributes() []Attribute {
return n.attributes
}
// RemoveAttributes implements Node.RemoveAttributes
func (n *BaseNode) RemoveAttributes() {
n.attributes = nil
}
// DumpHelper is a helper function to implement Node.Dump.
// kv is pairs of an attribute name and an attribute value.
// cb is a function called after wrote a name and attributes.
func DumpHelper(v Node, source []byte, level int, kv map[string]string, cb func(int)) {
name := v.Kind().String()
indent := strings.Repeat(" ", level)
fmt.Printf("%s%s {\n", indent, name)
indent2 := strings.Repeat(" ", level+1)
if v.Type() == TypeBlock {
fmt.Printf("%sRawText: \"", indent2)
for i := 0; i < v.Lines().Len(); i++ {
line := v.Lines().At(i)
fmt.Printf("%s", line.Value(source))
}
fmt.Printf("\"\n")
fmt.Printf("%sHasBlankPreviousLines: %v\n", indent2, v.HasBlankPreviousLines())
}
for name, value := range kv {
fmt.Printf("%s%s: %s\n", indent2, name, value)
}
if cb != nil {
cb(level + 1)
}
for c := v.FirstChild(); c != nil; c = c.NextSibling() {
c.Dump(source, level+1)
}
fmt.Printf("%s}\n", indent)
}
// WalkStatus represents a current status of the Walk function.
type WalkStatus int
const (
// WalkStop indicates no more walking needed.
WalkStop WalkStatus = iota + 1
// WalkSkipChildren indicates that Walk wont walk on children of current
// node.
WalkSkipChildren
// WalkContinue indicates that Walk can continue to walk.
WalkContinue
)
// Walker is a function that will be called when Walk find a
// new node.
// entering is set true before walks children, false after walked children.
// If Walker returns error, Walk function immediately stop walking.
type Walker func(n Node, entering bool) (WalkStatus, error)
// Walk walks a AST tree by the depth first search algorithm.
func Walk(n Node, walker Walker) error {
status, err := walker(n, true)
if err != nil || status == WalkStop {
return err
}
if status != WalkSkipChildren {
for c := n.FirstChild(); c != nil; c = c.NextSibling() {
if err = Walk(c, walker); err != nil {
return err
}
}
}
status, err = walker(n, false)
if err != nil || status == WalkStop {
return err
}
return nil
}