Scala example source code file (SubComponent.scala)

This example Scala source code file (SubComponent.scala) is included in my "Source Code Warehouse" project. The intent of this project is to help you more easily find Scala source code examples by using tags.

All credit for the original source code belongs to scala-lang.org; I'm just trying to make examples easier to find. (For my Scala work, see my Scala examples and tutorials.)

Scala tags/keywords

boolean, compiler, global, list, long, nil, nsc, option, phase, stdphase, t, weakreference

The SubComponent.scala Scala example source code

/* NSC -- new Scala compiler
 * Copyright 2005-2013 LAMP/EPFL
 * @author Martin Odersky
 */

package scala.tools.nsc

import scala.ref.WeakReference

/** An nsc sub-component.
 *
 *  @author Martin Odersky
 */
abstract class SubComponent {

  /** The global environment; overridden by instantiation in Global. */
  val global: Global

  /** The name of the phase */
  val phaseName: String

  /** Names of phases that must run before this phase. */
  val runsAfter: List[String]

  /** Names of phases that must run after this phase. Default is `Nil`. */
  val runsBefore: List[String] = Nil

  /** Name of the phase that this phase must follow immediately. */
  val runsRightAfter: Option[String]

  /** Names of phases required by this component. Default is `Nil`. */
  val requires: List[String] = Nil

  /** Is this component enabled? Default is true. */
  def enabled: Boolean = true

  /** True if this phase is not provided by a plug-in. */
  val internal: Boolean = true

  /** True if this phase runs before all other phases. Usually, `parser`. */
  val initial: Boolean = false

  /** True if this phase runs after all other phases. Usually, `terminal`. */
  val terminal: Boolean = false

  /** SubComponent are added to a HashSet and two phases are the same if they have the same name  */
  override def hashCode() = phaseName.hashCode()

  /** New flags defined by the phase which are not valid before */
  def phaseNewFlags: Long = 0

  /** New flags defined by the phase which are not valid until immediately after it */
  def phaseNextFlags: Long = 0

  /** The phase factory */
  def newPhase(prev: Phase): Phase

  private var ownPhaseCache: WeakReference[Phase] = new WeakReference(null)
  private var ownPhaseRunId = global.NoRunId

  @inline final def beforeOwnPhase[T](op: => T) = global.enteringPhase(ownPhase)(op)
  @inline final def afterOwnPhase[T](op: => T)  = global.exitingPhase(ownPhase)(op)

  /** The phase corresponding to this subcomponent in the current compiler run */
  def ownPhase: Phase = {
    ownPhaseCache.get match {
      case Some(phase) if ownPhaseRunId == global.currentRunId =>
        phase
      case _ =>
        val phase = global.currentRun.phaseNamed(phaseName)
        ownPhaseCache = new WeakReference(phase)
        ownPhaseRunId = global.currentRunId
        phase
    }
  }

  /** The phase defined by this subcomponent. Can be called only after phase is installed by newPhase. */
  //  lazy val ownPhase: Phase = global.currentRun.phaseNamed(phaseName)

  /** A standard phase template */
  abstract class StdPhase(prev: Phase) extends global.GlobalPhase(prev) {
    def name = phaseName
    override def newFlags = phaseNewFlags
    override def nextFlags = phaseNextFlags
  }
}