gotosocial/vendor/github.com/yuin/goldmark/ast/ast.go

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// 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{}
}
// 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)
// OwnerDocument returns this node's owner document.
// If this node is not a child of the Document node, OwnerDocument
// returns nil.
OwnerDocument() *Document
// 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 partialliy.
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.SetParent(nil)
c.SetPreviousSibling(nil)
next := c.NextSibling()
c.SetNextSibling(nil)
c = next
}
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)
}
}
// OwnerDocument implements Node.OwnerDocument.
func (n *BaseNode) OwnerDocument() *Document {
d := n.Parent()
for {
p := d.Parent()
if p == nil {
if v, ok := d.(*Document); ok {
return v
}
break
}
d = p
}
return nil
}
// 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 {
_, err := walkHelper(n, walker)
return err
}
func walkHelper(n Node, walker Walker) (WalkStatus, error) {
status, err := walker(n, true)
if err != nil || status == WalkStop {
return status, err
}
if status != WalkSkipChildren {
for c := n.FirstChild(); c != nil; c = c.NextSibling() {
if st, err := walkHelper(c, walker); err != nil || st == WalkStop {
return WalkStop, err
}
}
}
status, err = walker(n, false)
if err != nil || status == WalkStop {
return WalkStop, err
}
return WalkContinue, nil
}