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Diffstat (limited to 'vendor/github.com/russross/blackfriday/node.go')
| -rw-r--r-- | vendor/github.com/russross/blackfriday/node.go | 354 |
1 files changed, 354 insertions, 0 deletions
diff --git a/vendor/github.com/russross/blackfriday/node.go b/vendor/github.com/russross/blackfriday/node.go new file mode 100644 index 00000000..51b9e8c1 --- /dev/null +++ b/vendor/github.com/russross/blackfriday/node.go @@ -0,0 +1,354 @@ +package blackfriday + +import ( + "bytes" + "fmt" +) + +// NodeType specifies a type of a single node of a syntax tree. Usually one +// node (and its type) corresponds to a single markdown feature, e.g. emphasis +// or code block. +type NodeType int + +// Constants for identifying different types of nodes. See NodeType. +const ( + Document NodeType = iota + BlockQuote + List + Item + Paragraph + Heading + HorizontalRule + Emph + Strong + Del + Link + Image + Text + HTMLBlock + CodeBlock + Softbreak + Hardbreak + Code + HTMLSpan + Table + TableCell + TableHead + TableBody + TableRow +) + +var nodeTypeNames = []string{ + Document: "Document", + BlockQuote: "BlockQuote", + List: "List", + Item: "Item", + Paragraph: "Paragraph", + Heading: "Heading", + HorizontalRule: "HorizontalRule", + Emph: "Emph", + Strong: "Strong", + Del: "Del", + Link: "Link", + Image: "Image", + Text: "Text", + HTMLBlock: "HTMLBlock", + CodeBlock: "CodeBlock", + Softbreak: "Softbreak", + Hardbreak: "Hardbreak", + Code: "Code", + HTMLSpan: "HTMLSpan", + Table: "Table", + TableCell: "TableCell", + TableHead: "TableHead", + TableBody: "TableBody", + TableRow: "TableRow", +} + +func (t NodeType) String() string { + return nodeTypeNames[t] +} + +// ListData contains fields relevant to a List and Item node type. +type ListData struct { + ListFlags ListType + Tight bool // Skip <p>s around list item data if true + BulletChar byte // '*', '+' or '-' in bullet lists + Delimiter byte // '.' or ')' after the number in ordered lists + RefLink []byte // If not nil, turns this list item into a footnote item and triggers different rendering + IsFootnotesList bool // This is a list of footnotes +} + +// LinkData contains fields relevant to a Link node type. +type LinkData struct { + Destination []byte // Destination is what goes into a href + Title []byte // Title is the tooltip thing that goes in a title attribute + NoteID int // NoteID contains a serial number of a footnote, zero if it's not a footnote + Footnote *Node // If it's a footnote, this is a direct link to the footnote Node. Otherwise nil. +} + +// CodeBlockData contains fields relevant to a CodeBlock node type. +type CodeBlockData struct { + IsFenced bool // Specifies whether it's a fenced code block or an indented one + Info []byte // This holds the info string + FenceChar byte + FenceLength int + FenceOffset int +} + +// TableCellData contains fields relevant to a TableCell node type. +type TableCellData struct { + IsHeader bool // This tells if it's under the header row + Align CellAlignFlags // This holds the value for align attribute +} + +// HeadingData contains fields relevant to a Heading node type. +type HeadingData struct { + Level int // This holds the heading level number + HeadingID string // This might hold heading ID, if present + IsTitleblock bool // Specifies whether it's a title block +} + +// Node is a single element in the abstract syntax tree of the parsed document. +// It holds connections to the structurally neighboring nodes and, for certain +// types of nodes, additional information that might be needed when rendering. +type Node struct { + Type NodeType // Determines the type of the node + Parent *Node // Points to the parent + FirstChild *Node // Points to the first child, if any + LastChild *Node // Points to the last child, if any + Prev *Node // Previous sibling; nil if it's the first child + Next *Node // Next sibling; nil if it's the last child + + Literal []byte // Text contents of the leaf nodes + + HeadingData // Populated if Type is Heading + ListData // Populated if Type is List + CodeBlockData // Populated if Type is CodeBlock + LinkData // Populated if Type is Link + TableCellData // Populated if Type is TableCell + + content []byte // Markdown content of the block nodes + open bool // Specifies an open block node that has not been finished to process yet +} + +// NewNode allocates a node of a specified type. +func NewNode(typ NodeType) *Node { + return &Node{ + Type: typ, + open: true, + } +} + +func (n *Node) String() string { + ellipsis := "" + snippet := n.Literal + if len(snippet) > 16 { + snippet = snippet[:16] + ellipsis = "..." + } + return fmt.Sprintf("%s: '%s%s'", n.Type, snippet, ellipsis) +} + +// Unlink removes node 'n' from the tree. +// It panics if the node is nil. +func (n *Node) Unlink() { + if n.Prev != nil { + n.Prev.Next = n.Next + } else if n.Parent != nil { + n.Parent.FirstChild = n.Next + } + if n.Next != nil { + n.Next.Prev = n.Prev + } else if n.Parent != nil { + n.Parent.LastChild = n.Prev + } + n.Parent = nil + n.Next = nil + n.Prev = nil +} + +// AppendChild adds a node 'child' as a child of 'n'. +// It panics if either node is nil. +func (n *Node) AppendChild(child *Node) { + child.Unlink() + child.Parent = n + if n.LastChild != nil { + n.LastChild.Next = child + child.Prev = n.LastChild + n.LastChild = child + } else { + n.FirstChild = child + n.LastChild = child + } +} + +// InsertBefore inserts 'sibling' immediately before 'n'. +// It panics if either node is nil. +func (n *Node) InsertBefore(sibling *Node) { + sibling.Unlink() + sibling.Prev = n.Prev + if sibling.Prev != nil { + sibling.Prev.Next = sibling + } + sibling.Next = n + n.Prev = sibling + sibling.Parent = n.Parent + if sibling.Prev == nil { + sibling.Parent.FirstChild = sibling + } +} + +func (n *Node) isContainer() bool { + switch n.Type { + case Document: + fallthrough + case BlockQuote: + fallthrough + case List: + fallthrough + case Item: + fallthrough + case Paragraph: + fallthrough + case Heading: + fallthrough + case Emph: + fallthrough + case Strong: + fallthrough + case Del: + fallthrough + case Link: + fallthrough + case Image: + fallthrough + case Table: + fallthrough + case TableHead: + fallthrough + case TableBody: + fallthrough + case TableRow: + fallthrough + case TableCell: + return true + default: + return false + } +} + +func (n *Node) canContain(t NodeType) bool { + if n.Type == List { + return t == Item + } + if n.Type == Document || n.Type == BlockQuote || n.Type == Item { + return t != Item + } + if n.Type == Table { + return t == TableHead || t == TableBody + } + if n.Type == TableHead || n.Type == TableBody { + return t == TableRow + } + if n.Type == TableRow { + return t == TableCell + } + return false +} + +// WalkStatus allows NodeVisitor to have some control over the tree traversal. +// It is returned from NodeVisitor and different values allow Node.Walk to +// decide which node to go to next. +type WalkStatus int + +const ( + // GoToNext is the default traversal of every node. + GoToNext WalkStatus = iota + // SkipChildren tells walker to skip all children of current node. + SkipChildren + // Terminate tells walker to terminate the traversal. + Terminate +) + +// NodeVisitor is a callback to be called when traversing the syntax tree. +// Called twice for every node: once with entering=true when the branch is +// first visited, then with entering=false after all the children are done. +type NodeVisitor func(node *Node, entering bool) WalkStatus + +// Walk is a convenience method that instantiates a walker and starts a +// traversal of subtree rooted at n. +func (n *Node) Walk(visitor NodeVisitor) { + w := newNodeWalker(n) + for w.current != nil { + status := visitor(w.current, w.entering) + switch status { + case GoToNext: + w.next() + case SkipChildren: + w.entering = false + w.next() + case Terminate: + return + } + } +} + +type nodeWalker struct { + current *Node + root *Node + entering bool +} + +func newNodeWalker(root *Node) *nodeWalker { + return &nodeWalker{ + current: root, + root: root, + entering: true, + } +} + +func (nw *nodeWalker) next() { + if (!nw.current.isContainer() || !nw.entering) && nw.current == nw.root { + nw.current = nil + return + } + if nw.entering && nw.current.isContainer() { + if nw.current.FirstChild != nil { + nw.current = nw.current.FirstChild + nw.entering = true + } else { + nw.entering = false + } + } else if nw.current.Next == nil { + nw.current = nw.current.Parent + nw.entering = false + } else { + nw.current = nw.current.Next + nw.entering = true + } +} + +func dump(ast *Node) { + fmt.Println(dumpString(ast)) +} + +func dumpR(ast *Node, depth int) string { + if ast == nil { + return "" + } + indent := bytes.Repeat([]byte("\t"), depth) + content := ast.Literal + if content == nil { + content = ast.content + } + result := fmt.Sprintf("%s%s(%q)\n", indent, ast.Type, content) + for n := ast.FirstChild; n != nil; n = n.Next { + result += dumpR(n, depth+1) + } + return result +} + +func dumpString(ast *Node) string { + return dumpR(ast, 0) +} |