package dotty.tools
package dottydoc
package model
package comment
/** The `MarkdownShortener` takes a node and *mutates* it and all children so
* that the displayed length of the generated HTML doesn't exceeed `maxLen`.
* This number defaults to 150 characters.
*
* @note calling `shorten` **will** mutate the Markdown AST node.
*/
class MarkdownShortener {
import com.vladsch.flexmark.ast._
def shorten(node: Node, maxLen: Int = 150): Node = {
var len = 0
var didUnlinkListItem = false
def count(node: Node, length: => Int, shortenOrUnlink: Int => Unit) = {
val remaining = math.max(maxLen - len, 0)
if (remaining == 0) node.unlink()
else {
if (length <= remaining) len += length
else {
shortenOrUnlink(remaining)
len = maxLen
}
}
}
val nodeVisitor = new NodeVisitor(
new VisitHandler(classOf[Text], new Visitor[Text] {
override def visit(node: Text) = count(
node,
node.getChars.length,
remaining => node.setChars(
node.getChars.subSequence(0, remaining).trimEnd.append("...")
)
)
}),
new VisitHandler(classOf[Code], new Visitor[Code] {
override def visit(node: Code) = count(
node,
node.getText.length,
remaining => node.setText(
node.getText.subSequence(0, remaining).trimEnd.append("...")
)
)
}),
new VisitHandler(classOf[Image], new Visitor[Image] {
override def visit(node: Image) = count(node, maxLen, _ => node.unlink())
}),
new VisitHandler(classOf[BulletListItem], new Visitor[BulletListItem] {
override def visit(node: BulletListItem) = count(
node,
if (didUnlinkListItem) maxLen
else node.getSegments.map(_.length).reduceLeft(_ + _),
_ => {
node.unlink()
didUnlinkListItem = true // unlink all following bullets
}
)
}),
new VisitHandler(classOf[OrderedListItem], new Visitor[OrderedListItem] {
override def visit(node: OrderedListItem) = count(
node,
if (didUnlinkListItem) maxLen
else node.getSegments.map(_.length).reduceLeft(_ + _),
_ => {
node.unlink()
didUnlinkListItem = true // unlink all following bullets
}
)
})
)
nodeVisitor.visit(node)
node
}
}
