diff options
Diffstat (limited to 'src/library/scala/reflect/ClassManifest.scala')
| -rw-r--r-- | src/library/scala/reflect/ClassManifest.scala | 263 |
1 files changed, 0 insertions, 263 deletions
diff --git a/src/library/scala/reflect/ClassManifest.scala b/src/library/scala/reflect/ClassManifest.scala deleted file mode 100644 index 37be067614..0000000000 --- a/src/library/scala/reflect/ClassManifest.scala +++ /dev/null @@ -1,263 +0,0 @@ -/* __ *\ -** ________ ___ / / ___ Scala API ** -** / __/ __// _ | / / / _ | (c) 2007-2011, LAMP/EPFL ** -** __\ \/ /__/ __ |/ /__/ __ | http://scala-lang.org/ ** -** /____/\___/_/ |_/____/_/ | | ** -** |/ ** -\* */ - -/* [Martin] - * Todo: ClassManifests currently contain all available type arguments. - * That's a waste of cycles if all that's needed is the class. - * We should have instead consider a structure like this: - * - * OptManifest - * / \ - * / \ - * PartialManifest ClassManifest - * \ / - * \ / - * Manifest - * - * where PartialManifest means: generate as much as you can, use NoManifest - * where nothing is known, and - * ClassManifest means: generate exactly the top-level class, and nothing else. - */ -package scala.reflect - -import scala.collection.mutable.{ WrappedArray, ArrayBuilder } -import java.lang.{ Class => jClass } - -/** A `ClassManifest[T]` is an opaque descriptor for type `T`. - * It is used by the compiler to preserve information necessary - * for instantiating `Arrays` in those cases where the element type - * is unknown at compile time. - * - * The type-relation operators make an effort to present a more accurate - * picture than can be realized with erased types, but they should not be - * relied upon to give correct answers. In particular they are likely to - * be wrong when variance is involved or when a subtype has a different - * number of type arguments than a supertype. - */ -trait ClassManifest[T] extends OptManifest[T] with Equals with Serializable { - /** A class representing the type `U` to which `T` would be erased. Note - * that there is no subtyping relationship between `T` and `U`. */ - def erasure: jClass[_] - - /** The Scala type described by this manifest. - */ - lazy val tpe: mirror.Type = mirror.classToType(erasure) - - def symbol: mirror.Symbol = mirror.classToSymbol(erasure) - - private def subtype(sub: jClass[_], sup: jClass[_]): Boolean = { - def loop(left: Set[jClass[_]], seen: Set[jClass[_]]): Boolean = { - left.nonEmpty && { - val next = left.head - val supers = next.getInterfaces.toSet ++ Option(next.getSuperclass) - supers(sup) || { - val xs = left ++ supers filterNot seen - loop(xs - next, seen + next) - } - } - } - loop(Set(sub), Set()) - } - - private def subargs(args1: List[OptManifest[_]], args2: List[OptManifest[_]]) = (args1 corresponds args2) { - // !!! [Martin] this is wrong, need to take variance into account - case (x: ClassManifest[_], y: ClassManifest[_]) => x <:< y - case (x, y) => (x eq NoManifest) && (y eq NoManifest) - } - - /** Tests whether the type represented by this manifest is a subtype - * of the type represented by `that` manifest, subject to the limitations - * described in the header. - */ - def <:<(that: ClassManifest[_]): Boolean = { - // All types which could conform to these types will override <:<. - def cannotMatch = { - import Manifest._ - that.isInstanceOf[AnyValManifest[_]] || (that eq AnyVal) || (that eq Nothing) || (that eq Null) - } - - // This is wrong, and I don't know how it can be made right - // without more development of Manifests, due to arity-defying - // relationships like: - // - // List[String] <: AnyRef - // Map[Int, Int] <: Iterable[(Int, Int)] - // - // Given the manifest for Map[A, B] how do I determine that a - // supertype has single type argument (A, B) ? I don't see how we - // can say whether X <:< Y when type arguments are involved except - // when the erasure is the same, even before considering variance. - !cannotMatch && { - // this part is wrong for not considering variance - if (this.erasure == that.erasure) - subargs(this.typeArguments, that.typeArguments) - // this part is wrong for punting unless the rhs has no type - // arguments, but it's better than a blindfolded pinata swing. - else - that.typeArguments.isEmpty && subtype(this.erasure, that.erasure) - } - } - - /** Tests whether the type represented by this manifest is a supertype - * of the type represented by `that` manifest, subject to the limitations - * described in the header. - */ - def >:>(that: ClassManifest[_]): Boolean = - that <:< this - - def canEqual(other: Any) = other match { - case _: ClassManifest[_] => true - case _ => false - } - - /** Tests whether the type represented by this manifest is equal to - * the type represented by `that` manifest, subject to the limitations - * described in the header. - */ - override def equals(that: Any): Boolean = that match { - case m: ClassManifest[_] => (m canEqual this) && (this.erasure == m.erasure) - case _ => false - } - override def hashCode = this.erasure.## - - protected def arrayClass[T](tp: jClass[_]): jClass[Array[T]] = - java.lang.reflect.Array.newInstance(tp, 0).getClass.asInstanceOf[jClass[Array[T]]] - - def arrayManifest: ClassManifest[Array[T]] = - ClassManifest.classType[Array[T]](arrayClass[T](erasure), this) - - def newArray(len: Int): Array[T] = - java.lang.reflect.Array.newInstance(erasure, len).asInstanceOf[Array[T]] - - def newArray2(len: Int): Array[Array[T]] = - java.lang.reflect.Array.newInstance(arrayClass[T](erasure), len) - .asInstanceOf[Array[Array[T]]] - - def newArray3(len: Int): Array[Array[Array[T]]] = - java.lang.reflect.Array.newInstance(arrayClass[Array[T]](arrayClass[T](erasure)), len) - .asInstanceOf[Array[Array[Array[T]]]] - - def newArray4(len: Int): Array[Array[Array[Array[T]]]] = - java.lang.reflect.Array.newInstance(arrayClass[Array[Array[T]]](arrayClass[Array[T]](arrayClass[T](erasure))), len) - .asInstanceOf[Array[Array[Array[Array[T]]]]] - - def newArray5(len: Int): Array[Array[Array[Array[Array[T]]]]] = - java.lang.reflect.Array.newInstance(arrayClass[Array[Array[Array[T]]]](arrayClass[Array[Array[T]]](arrayClass[Array[T]](arrayClass[T](erasure)))), len) - .asInstanceOf[Array[Array[Array[Array[Array[T]]]]]] - - def newWrappedArray(len: Int): WrappedArray[T] = - // it's safe to assume T <: AnyRef here because the method is overridden for all value type manifests - new WrappedArray.ofRef[T with AnyRef](newArray(len).asInstanceOf[Array[T with AnyRef]]).asInstanceOf[WrappedArray[T]] - - def newArrayBuilder(): ArrayBuilder[T] = - // it's safe to assume T <: AnyRef here because the method is overridden for all value type manifests - new ArrayBuilder.ofRef[T with AnyRef]()(this.asInstanceOf[ClassManifest[T with AnyRef]]).asInstanceOf[ArrayBuilder[T]] - - def typeArguments: List[OptManifest[_]] = List() - - protected def argString = - if (typeArguments.nonEmpty) typeArguments.mkString("[", ", ", "]") - else if (erasure.isArray) "["+ClassManifest.fromClass(erasure.getComponentType)+"]" - else "" -} - -/** The object `ClassManifest` defines factory methods for manifests. - * It is intended for use by the compiler and should not be used in client code. - */ -object ClassManifest { - val Byte = Manifest.Byte - val Short = Manifest.Short - val Char = Manifest.Char - val Int = Manifest.Int - val Long = Manifest.Long - val Float = Manifest.Float - val Double = Manifest.Double - val Boolean = Manifest.Boolean - val Unit = Manifest.Unit - val Any = Manifest.Any - val Object = Manifest.Object - val AnyVal = Manifest.AnyVal - val Nothing = Manifest.Nothing - val Null = Manifest.Null - - def fromClass[T](clazz: jClass[T]): ClassManifest[T] = clazz match { - case java.lang.Byte.TYPE => Byte.asInstanceOf[ClassManifest[T]] - case java.lang.Short.TYPE => Short.asInstanceOf[ClassManifest[T]] - case java.lang.Character.TYPE => Char.asInstanceOf[ClassManifest[T]] - case java.lang.Integer.TYPE => Int.asInstanceOf[ClassManifest[T]] - case java.lang.Long.TYPE => Long.asInstanceOf[ClassManifest[T]] - case java.lang.Float.TYPE => Float.asInstanceOf[ClassManifest[T]] - case java.lang.Double.TYPE => Double.asInstanceOf[ClassManifest[T]] - case java.lang.Boolean.TYPE => Boolean.asInstanceOf[ClassManifest[T]] - case java.lang.Void.TYPE => Unit.asInstanceOf[ClassManifest[T]] - case _ => classType[T with AnyRef](clazz).asInstanceOf[ClassManifest[T]] - } - - def singleType[T <: AnyRef](value: AnyRef): Manifest[T] = Manifest.singleType(value) - - /** ClassManifest for the class type `clazz`, where `clazz` is - * a top-level or static class. - * @note This no-prefix, no-arguments case is separate because we - * it's called from ScalaRunTime.boxArray itself. If we - * pass varargs as arrays into this, we get an infinitely recursive call - * to boxArray. (Besides, having a separate case is more efficient) - */ - def classType[T](clazz: jClass[_]): ClassManifest[T] = - new ClassTypeManifest[T](None, clazz, Nil) - - /** ClassManifest for the class type `clazz[args]`, where `clazz` is - * a top-level or static class and `args` are its type arguments */ - def classType[T](clazz: jClass[_], arg1: OptManifest[_], args: OptManifest[_]*): ClassManifest[T] = - new ClassTypeManifest[T](None, clazz, arg1 :: args.toList) - - /** ClassManifest for the class type `clazz[args]`, where `clazz` is - * a class with non-package prefix type `prefix` and type arguments `args`. - */ - def classType[T](prefix: OptManifest[_], clazz: jClass[_], args: OptManifest[_]*): ClassManifest[T] = - new ClassTypeManifest[T](Some(prefix), clazz, args.toList) - - def arrayType[T](arg: OptManifest[_]): ClassManifest[Array[T]] = arg match { - case NoManifest => Object.asInstanceOf[ClassManifest[Array[T]]] - case m: ClassManifest[_] => m.asInstanceOf[ClassManifest[T]].arrayManifest - } - - /** ClassManifest for the abstract type `prefix # name`. `upperBound` is not - * strictly necessary as it could be obtained by reflection. It was - * added so that erasure can be calculated without reflection. */ - def abstractType[T](prefix: OptManifest[_], name: String, clazz: jClass[_], args: OptManifest[_]*): ClassManifest[T] = - new ClassManifest[T] { - def erasure = clazz - override val typeArguments = args.toList - override def toString = prefix.toString+"#"+name+argString - } - - /** ClassManifest for the abstract type `prefix # name`. `upperBound` is not - * strictly necessary as it could be obtained by reflection. It was - * added so that erasure can be calculated without reflection. - * todo: remove after next boostrap - */ - def abstractType[T](prefix: OptManifest[_], name: String, upperbound: ClassManifest[_], args: OptManifest[_]*): ClassManifest[T] = - new ClassManifest[T] { - def erasure = upperbound.erasure - override val typeArguments = args.toList - override def toString = prefix.toString+"#"+name+argString - } -} - -/** Manifest for the class type `clazz[args]`, where `clazz` is - * a top-level or static class: todo: we should try to merge this with Manifest's class */ -private class ClassTypeManifest[T]( - prefix: Option[OptManifest[_]], - val erasure: jClass[_], - override val typeArguments: List[OptManifest[_]]) extends ClassManifest[T] -{ - override def toString = - (if (prefix.isEmpty) "" else prefix.get.toString+"#") + - (if (erasure.isArray) "Array" else erasure.getName) + - argString -} |