scala.coursier.util.Tree.scala Maven / Gradle / Ivy
package coursier.util
import scala.collection.mutable.ArrayBuffer
object Tree {
def apply[A](roots: IndexedSeq[A])(children: A => Seq[A]) =
new Tree(roots, children)
}
final class Tree[A](val roots: IndexedSeq[A], val children: A => Seq[A]) {
def render(show: A => String): String =
customRender()(show)
def customRender(
assumeTopRoot: Boolean = true,
extraPrefix: String = "",
extraSeparator: Option[String] = None
)(show: A => String): String = {
/** Recursively go down the resolution for the elems to construct the tree for print out.
*
* @param elems
* Seq of Elems that have been resolved
* @param ancestors
* a set of Elems to keep track for cycle detection
* @param prefix
* prefix for the print out
* @param acc
* accumulation method on a string
*/
def recursivePrint(
elems: Seq[A],
ancestors: Set[A],
prefix: String,
isRoot: Boolean,
acc: String => Unit
): Unit = {
val unseenElems: Seq[A] = elems.filterNot(ancestors.contains)
val unseenElemsLen = unseenElems.length
for ((elem, idx) <- unseenElems.iterator.zipWithIndex) {
val isLast = idx == unseenElemsLen - 1
val tee = if (!assumeTopRoot && isRoot) "" else if (isLast) "└─ " else "├─ "
acc(prefix + tee + show(elem))
val extraPrefix = if (!assumeTopRoot && isRoot) "" else if (isLast) " " else "│ "
recursivePrint(children(elem), ancestors + elem, prefix + extraPrefix, isRoot = false, acc)
for (sep <- extraSeparator)
if (!assumeTopRoot && isRoot)
acc(sep)
}
}
val b = new ArrayBuffer[String]
recursivePrint(roots, Set(), extraPrefix, isRoot = true, b += _)
b.mkString(System.lineSeparator())
}
}