resurrects manifests in their pre-2.10 glory

1 files changed, 259 insertions, 0 deletions

diff --git a/src/library/scala/reflect/Manifest.scala b/src/library/scala/reflect/Manifest.scala
new file mode 100644
index 0000000000..da029f046d
--- /dev/null
+++ b/src/library/scala/reflect/Manifest.scala
@@ -0,0 +1,259 @@
+/*                     __                                               *\
+**     ________ ___   / /  ___     Scala API                            **
+**    / __/ __// _ | / /  / _ |    (c) 2007-2011, LAMP/EPFL             **
+**  __\ \/ /__/ __ |/ /__/ __ |    http://scala-lang.org/               **
+** /____/\___/_/ |_/____/_/ | |                                         **
+**                          |/                                          **
+\*                                                                      */
+
+package scala.reflect
+
+import scala.collection.mutable.{ ArrayBuilder, WrappedArray }
+import mirror._
+
+/** A `Manifest[T]` is an opaque descriptor for type T.  Its supported use
+ *  is to give access to the erasure of the type as a `Class` instance, as
+ *  is necessary for the creation of native `Arrays` if the class is not
+ *  known at compile time.
+ *
+ *  The type-relation operators `<:<` and `=:=` should be considered
+ *  approximations only, as there are numerous aspects of type conformance
+ *  which are not yet adequately represented in manifests.
+ *
+ *  Example usages:
+{{{
+  def arr[T] = new Array[T](0)                          // does not compile
+  def arr[T](implicit m: Manifest[T]) = new Array[T](0) // compiles
+  def arr[T: Manifest] = new Array[T](0)                // shorthand for the preceding
+
+  // Methods manifest, classManifest, and optManifest are in [[scala.Predef]].
+  def isApproxSubType[T: Manifest, U: Manifest] = manifest[T] <:< manifest[U]
+  isApproxSubType[List[String], List[AnyRef]] // true
+  isApproxSubType[List[String], List[Int]]    // false
+
+  def methods[T: ClassManifest] = classManifest[T].erasure.getMethods
+  def retType[T: ClassManifest](name: String) =
+    methods[T] find (_.getName == name) map (_.getGenericReturnType)
+
+  retType[Map[_, _]]("values")  // Some(scala.collection.Iterable<B>)
+}}}
+ *
+ */
+@annotation.implicitNotFound(msg = "No Manifest available for ${T}.")
+@deprecated("Use `@scala.reflect.ConcreteTypeTag` instead", "2.10.0")
+trait Manifest[T] extends ClassManifest[T] with Equals {
+  override def typeArguments: List[Manifest[_]] = Nil
+
+  override def arrayManifest: Manifest[Array[T]] =
+    Manifest.classType[Array[T]](arrayClass[T](erasure), this)
+
+  override def canEqual(that: Any): Boolean = that match {
+    case _: Manifest[_]   => true
+    case _                => false
+  }
+  /** Note: testing for erasure here is important, as it is many times
+   *  faster than <:< and rules out most comparisons.
+   */
+  override def equals(that: Any): Boolean = that match {
+    case m: Manifest[_] => (m canEqual this) && (this.erasure == m.erasure) && (this <:< m) && (m <:< this)
+    case _              => false
+  }
+  override def hashCode = this.erasure.##
+}
+
+@deprecated("Use type tags and manually check the corresponding class or type instead", "2.10.0")
+abstract class AnyValManifest[T <: AnyVal](override val toString: String) extends Manifest[T] with Equals {
+  override def <:<(that: ClassManifest[_]): Boolean =
+    (that eq this) || (that eq Manifest.Any) || (that eq Manifest.AnyVal)
+  override def canEqual(other: Any) = other match {
+    case _: AnyValManifest[_] => true
+    case _                    => false
+  }
+  override def equals(that: Any): Boolean = this eq that.asInstanceOf[AnyRef]
+  override val hashCode = System.identityHashCode(this)
+}
+
+/** The object `Manifest` defines factory methods for manifests.
+ *  It is intended for use by the compiler and should not be used
+ *  in client code.
+ */
+@deprecated("Use `@scala.reflect.ConcreteTypeTag` instead", "2.10.0")
+object Manifest {
+  def valueManifests: List[AnyValManifest[_]] =
+    List(Byte, Short, Char, Int, Long, Float, Double, Boolean, Unit)
+
+  val Byte: AnyValManifest[Byte] = new AnyValManifest[scala.Byte]("Byte") {
+    def erasure = java.lang.Byte.TYPE
+    override def newArray(len: Int): Array[Byte] = new Array[Byte](len)
+    override def newWrappedArray(len: Int): WrappedArray[Byte] = new WrappedArray.ofByte(new Array[Byte](len))
+    override def newArrayBuilder(): ArrayBuilder[Byte] = new ArrayBuilder.ofByte()
+    private def readResolve(): Any = Manifest.Byte
+  }
+
+  val Short: AnyValManifest[Short] = new AnyValManifest[scala.Short]("Short") {
+    def erasure = java.lang.Short.TYPE
+    override def newArray(len: Int): Array[Short] = new Array[Short](len)
+    override def newWrappedArray(len: Int): WrappedArray[Short] = new WrappedArray.ofShort(new Array[Short](len))
+    override def newArrayBuilder(): ArrayBuilder[Short] = new ArrayBuilder.ofShort()
+    private def readResolve(): Any = Manifest.Short
+  }
+
+  val Char: AnyValManifest[Char] = new AnyValManifest[scala.Char]("Char") {
+    def erasure = java.lang.Character.TYPE
+    override def newArray(len: Int): Array[Char] = new Array[Char](len)
+    override def newWrappedArray(len: Int): WrappedArray[Char] = new WrappedArray.ofChar(new Array[Char](len))
+    override def newArrayBuilder(): ArrayBuilder[Char] = new ArrayBuilder.ofChar()
+    private def readResolve(): Any = Manifest.Char
+  }
+
+  val Int: AnyValManifest[Int] = new AnyValManifest[scala.Int]("Int") {
+    def erasure = java.lang.Integer.TYPE
+    override def newArray(len: Int): Array[Int] = new Array[Int](len)
+    override def newWrappedArray(len: Int): WrappedArray[Int] = new WrappedArray.ofInt(new Array[Int](len))
+    override def newArrayBuilder(): ArrayBuilder[Int] = new ArrayBuilder.ofInt()
+    private def readResolve(): Any = Manifest.Int
+  }
+
+  val Long: AnyValManifest[Long] = new AnyValManifest[scala.Long]("Long") {
+    def erasure = java.lang.Long.TYPE
+    override def newArray(len: Int): Array[Long] = new Array[Long](len)
+    override def newWrappedArray(len: Int): WrappedArray[Long] = new WrappedArray.ofLong(new Array[Long](len))
+    override def newArrayBuilder(): ArrayBuilder[Long] = new ArrayBuilder.ofLong()
+    private def readResolve(): Any = Manifest.Long
+  }
+
+  val Float: AnyValManifest[Float] = new AnyValManifest[scala.Float]("Float") {
+    def erasure = java.lang.Float.TYPE
+    override def newArray(len: Int): Array[Float] = new Array[Float](len)
+    override def newWrappedArray(len: Int): WrappedArray[Float] = new WrappedArray.ofFloat(new Array[Float](len))
+    override def newArrayBuilder(): ArrayBuilder[Float] = new ArrayBuilder.ofFloat()
+    private def readResolve(): Any = Manifest.Float
+  }
+
+  val Double: AnyValManifest[Double] = new AnyValManifest[scala.Double]("Double") {
+    def erasure = java.lang.Double.TYPE
+    override def newArray(len: Int): Array[Double] = new Array[Double](len)
+    override def newWrappedArray(len: Int): WrappedArray[Double] = new WrappedArray.ofDouble(new Array[Double](len))
+    override def newArrayBuilder(): ArrayBuilder[Double] = new ArrayBuilder.ofDouble()
+    private def readResolve(): Any = Manifest.Double
+  }
+
+  val Boolean: AnyValManifest[Boolean] = new AnyValManifest[scala.Boolean]("Boolean") {
+    def erasure = java.lang.Boolean.TYPE
+    override def newArray(len: Int): Array[Boolean] = new Array[Boolean](len)
+    override def newWrappedArray(len: Int): WrappedArray[Boolean] = new WrappedArray.ofBoolean(new Array[Boolean](len))
+    override def newArrayBuilder(): ArrayBuilder[Boolean] = new ArrayBuilder.ofBoolean()
+    private def readResolve(): Any = Manifest.Boolean
+  }
+
+  val Unit: AnyValManifest[Unit] = new AnyValManifest[scala.Unit]("Unit") {
+    def erasure = java.lang.Void.TYPE
+    override def newArray(len: Int): Array[Unit] = new Array[Unit](len)
+    override def newWrappedArray(len: Int): WrappedArray[Unit] = new WrappedArray.ofUnit(new Array[Unit](len))
+    override def newArrayBuilder(): ArrayBuilder[Unit] = new ArrayBuilder.ofUnit()
+    private def readResolve(): Any = Manifest.Unit
+  }
+
+  val Any: Manifest[scala.Any] = new PhantomManifest[scala.Any]("Any") {
+    override def <:<(that: ClassManifest[_]): Boolean = (that eq this)
+    private def readResolve(): Any = Manifest.Any
+  }
+
+  val Object: Manifest[java.lang.Object] = new PhantomManifest[java.lang.Object]("Object") {
+    override def <:<(that: ClassManifest[_]): Boolean = (that eq this) || (that eq Any)
+    private def readResolve(): Any = Manifest.Object
+  }
+
+  val AnyVal: Manifest[scala.AnyVal] = new PhantomManifest[scala.AnyVal]("AnyVal") {
+    override def <:<(that: ClassManifest[_]): Boolean = (that eq this) || (that eq Any)
+    private def readResolve(): Any = Manifest.AnyVal
+  }
+
+  val Null: Manifest[scala.Null] = new PhantomManifest[scala.Null]("Null") {
+    override def <:<(that: ClassManifest[_]): Boolean =
+      (that ne null) && (that ne Nothing) && !(that <:< AnyVal)
+    private def readResolve(): Any = Manifest.Null
+  }
+
+  val Nothing: Manifest[scala.Nothing] = new PhantomManifest[scala.Nothing]("Nothing") {
+    override def <:<(that: ClassManifest[_]): Boolean = (that ne null)
+    private def readResolve(): Any = Manifest.Nothing
+  }
+
+  private class SingletonTypeManifest[T <: AnyRef](value: AnyRef) extends Manifest[T] {
+    lazy val erasure = value.getClass
+    override lazy val toString = value.toString + ".type"
+  }
+
+  /** Manifest for the singleton type `value.type`. */
+  def singleType[T <: AnyRef](value: AnyRef): Manifest[T] =
+    new SingletonTypeManifest[T](value)
+
+  /** Manifest for the class type `clazz[args]`, 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: Predef.Class[_]): Manifest[T] =
+    new ClassTypeManifest[T](None, clazz, Nil)
+
+  /** Manifest for the class type `clazz`, where `clazz` is
+    * a top-level or static class and args are its type arguments. */
+  def classType[T](clazz: Predef.Class[T], arg1: Manifest[_], args: Manifest[_]*): Manifest[T] =
+    new ClassTypeManifest[T](None, clazz, arg1 :: args.toList)
+
+  /** Manifest 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: Manifest[_], clazz: Predef.Class[_], args: Manifest[_]*): Manifest[T] =
+    new ClassTypeManifest[T](Some(prefix), clazz, args.toList)
+
+  private abstract class PhantomManifest[T](override val toString: String) extends ClassTypeManifest[T](None, classOf[java.lang.Object], Nil) {
+    override def equals(that: Any): Boolean = this eq that.asInstanceOf[AnyRef]
+    override val hashCode = System.identityHashCode(this)
+  }
+
+  /** Manifest for the class type `clazz[args]`, where `clazz` is
+    * a top-level or static class. */
+  private class ClassTypeManifest[T](prefix: Option[Manifest[_]],
+                                     val erasure: Predef.Class[_],
+                                     override val typeArguments: List[Manifest[_]]) extends Manifest[T] {
+    override def toString =
+      (if (prefix.isEmpty) "" else prefix.get.toString+"#") +
+      (if (erasure.isArray) "Array" else erasure.getName) +
+      argString
+   }
+
+  def arrayType[T](arg: Manifest[_]): Manifest[Array[T]] =
+    arg.asInstanceOf[Manifest[T]].arrayManifest
+
+  /** Manifest 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: Manifest[_], name: String, upperBound: Predef.Class[_], args: Manifest[_]*): Manifest[T] =
+    new Manifest[T] {
+      def erasure = upperBound
+      override val typeArguments = args.toList
+      override def toString = prefix.toString+"#"+name+argString
+    }
+
+  /** Manifest for the unknown type `_ >: L <: U` in an existential.
+    */
+  def wildcardType[T](lowerBound: Manifest[_], upperBound: Manifest[_]): Manifest[T] =
+    new Manifest[T] {
+      def erasure = upperBound.erasure
+      override def toString =
+        "_" +
+        (if (lowerBound eq Nothing) "" else " >: "+lowerBound) +
+        (if (upperBound eq Nothing) "" else " <: "+upperBound)
+    }
+
+  /** Manifest for the intersection type `parents_0 with ... with parents_n'. */
+  def intersectionType[T](parents: Manifest[_]*): Manifest[T] =
+    new Manifest[T] {
+      def erasure = parents.head.erasure
+      override def toString = parents.mkString(" with ")
+    }
+}
\ No newline at end of file