sbt/util/collection/Attributes.scala

106 lines
3.8 KiB
Scala

/* sbt -- Simple Build Tool
* Copyright 2010 Mark Harrah
*/
package sbt
import Types._
import scala.reflect.Manifest
// T must be invariant to work properly.
// Because it is sealed and the only instances go through AttributeKey.apply,
// a single AttributeKey instance cannot conform to AttributeKey[T] for different Ts
sealed trait AttributeKey[T] {
def manifest: Manifest[T]
def label: String
def description: Option[String]
def extend: Seq[AttributeKey[_]]
override final def toString = label
override final def hashCode = label.hashCode
override final def equals(o: Any) = (this eq o.asInstanceOf[AnyRef]) || (o match {
case a: AttributeKey[t] => a.label == this.label && a.manifest == this.manifest
case _ => false
})
}
object AttributeKey
{
def apply[T](name: String)(implicit mf: Manifest[T]): AttributeKey[T] = new AttributeKey[T] {
def manifest = mf
def label = name
def description = None
def extend = Nil
}
def apply[T](name: String, description0: String)(implicit mf: Manifest[T]): AttributeKey[T] = new AttributeKey[T] {
def manifest = mf
def label = name
def description = Some(description0)
def extend = Nil
}
def apply[T](name: String, description0: String, extend0: Seq[AttributeKey[_]])(implicit mf: Manifest[T]): AttributeKey[T] = new AttributeKey[T] {
def manifest = mf
def label = name
def description = Some(description0)
def extend = extend0
}
}
trait AttributeMap
{
def apply[T](k: AttributeKey[T]): T
def get[T](k: AttributeKey[T]): Option[T]
def remove[T](k: AttributeKey[T]): AttributeMap
def contains[T](k: AttributeKey[T]): Boolean
def put[T](k: AttributeKey[T], value: T): AttributeMap
def keys: Iterable[AttributeKey[_]]
def ++(o: Iterable[AttributeEntry[_]]): AttributeMap
def ++(o: AttributeMap): AttributeMap
def entries: Iterable[AttributeEntry[_]]
def isEmpty: Boolean
}
object AttributeMap
{
val empty: AttributeMap = new BasicAttributeMap(Map.empty)
def apply(entries: Iterable[AttributeEntry[_]]): AttributeMap = empty ++ entries
def apply(entries: AttributeEntry[_]*): AttributeMap = empty ++ entries
implicit def toNatTrans(map: AttributeMap): AttributeKey ~> Id = new (AttributeKey ~> Id) {
def apply[T](key: AttributeKey[T]): T = map(key)
}
}
private class BasicAttributeMap(private val backing: Map[AttributeKey[_], Any]) extends AttributeMap
{
def isEmpty: Boolean = backing.isEmpty
def apply[T](k: AttributeKey[T]) = backing(k).asInstanceOf[T]
def get[T](k: AttributeKey[T]) = backing.get(k).asInstanceOf[Option[T]]
def remove[T](k: AttributeKey[T]): AttributeMap = new BasicAttributeMap( backing - k )
def contains[T](k: AttributeKey[T]) = backing.contains(k)
def put[T](k: AttributeKey[T], value: T): AttributeMap = new BasicAttributeMap( backing.updated(k, value) )
def keys: Iterable[AttributeKey[_]] = backing.keys
def ++(o: Iterable[AttributeEntry[_]]): AttributeMap =
{
val newBacking = (backing /: o) { case (b, AttributeEntry(key, value)) => b.updated(key, value) }
new BasicAttributeMap(newBacking)
}
def ++(o: AttributeMap): AttributeMap =
o match {
case bam: BasicAttributeMap => new BasicAttributeMap(backing ++ bam.backing)
case _ => o ++ this
}
def entries: Iterable[AttributeEntry[_]] =
for( (k: AttributeKey[kt], v) <- backing) yield AttributeEntry(k, v.asInstanceOf[kt])
override def toString = entries.mkString("(", ", ", ")")
}
// type inference required less generality
final case class AttributeEntry[T](key: AttributeKey[T], value: T)
{
override def toString = key.label + ": " + value
}
final case class Attributed[D](data: D)(val metadata: AttributeMap)
{
def put[T](key: AttributeKey[T], value: T): Attributed[D] = Attributed(data)(metadata.put(key, value))
}
object Attributed
{
implicit def blankSeq[T](in: Seq[T]): Seq[Attributed[T]] = in map blank
implicit def blank[T](data: T): Attributed[T] = Attributed(data)(AttributeMap.empty)
}