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Diffstat (limited to 'main/moduledefs/src/Cacher.scala')
-rw-r--r-- | main/moduledefs/src/Cacher.scala | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/main/moduledefs/src/Cacher.scala b/main/moduledefs/src/Cacher.scala new file mode 100644 index 00000000..023f03be --- /dev/null +++ b/main/moduledefs/src/Cacher.scala @@ -0,0 +1,35 @@ +package mill.moduledefs + +import scala.collection.mutable +import scala.reflect.macros.blackbox.Context + + +trait Cacher{ + private[this] lazy val cacherLazyMap = mutable.Map.empty[sourcecode.Enclosing, Any] + + protected[this] def cachedTarget[T](t: => T) + (implicit c: sourcecode.Enclosing): T = synchronized{ + cacherLazyMap.getOrElseUpdate(c, t).asInstanceOf[T] + } +} + +object Cacher{ + def impl0[T: c.WeakTypeTag](c: Context) + (t: c.Expr[T]): c.Expr[T] = { + c.Expr[T](wrapCached[T](c)(t.tree)) + } + def wrapCached[R: c.WeakTypeTag](c: Context)(t: c.Tree) = { + + import c.universe._ + val owner = c.internal.enclosingOwner + val ownerIsCacherClass = + owner.owner.isClass && + owner.owner.asClass.baseClasses.exists(_.fullName == "mill.moduledefs.Cacher") + + if (ownerIsCacherClass && owner.isMethod) q"this.cachedTarget[${weakTypeTag[R]}]($t)" + else c.abort( + c.enclosingPosition, + "T{} members must be defs defined in a Cacher class/trait/object body" + ) + } +}
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