Scala example source code file (Picklers.scala)

This example Scala source code file (Picklers.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

abstractfile, array, collection, compiler, condpickler, diff, freshrunreq, interruptreq, list, nsc, pickler, reflection, response, symbol, utilities

The Picklers.scala Scala example source code

/* NSC -- new Scala compiler
 * Copyright 2009-2013 Typesafe/Scala Solutions and LAMP/EPFL
 * @author Martin Odersky
 */
package scala.tools.nsc
package interactive

import util.InterruptReq
import scala.reflect.internal.util.{ SourceFile, BatchSourceFile }
import io.{ AbstractFile, PlainFile }
import util.EmptyAction
import scala.reflect.internal.util.Position
import Pickler._
import scala.collection.mutable
import mutable.ListBuffer

trait Picklers { self: Global =>

  lazy val freshRunReq =
    unitPickler
      .wrapped { _ => new FreshRunReq } { x => () }
      .labelled ("FreshRunReq")
      .cond (_.isInstanceOf[FreshRunReq])

      lazy val shutdownReq = singletonPickler(ShutdownReq)

  def defaultThrowable[T <: Throwable]: CondPickler[T] = javaInstancePickler[T] cond { _ => true }

  implicit lazy val throwable: Pickler[Throwable] =
    freshRunReq | shutdownReq | defaultThrowable

  implicit def abstractFile: Pickler[AbstractFile] =
    pkl[String]
      .wrapped[AbstractFile] { new PlainFile(_) } { _.path }
      .asClass (classOf[PlainFile])

  private val sourceFilesSeen = new mutable.HashMap[AbstractFile, Array[Char]] {
    override def default(key: AbstractFile) = Array()
  }

  type Diff = (Int /*start*/, Int /*end*/, String /*replacement*/)

  def delta(f: AbstractFile, cs: Array[Char]): Diff = {
    val bs = sourceFilesSeen(f)
    var start = 0
    while (start < bs.length && start < cs.length && bs(start) == cs(start)) start += 1
    var end = bs.length
    var end2 = cs.length
    while (end > start && end2 > start && bs(end - 1) == cs(end2 - 1)) { end -= 1; end2 -= 1 }
    sourceFilesSeen(f) = cs
    (start, end, cs.slice(start, end2).mkString(""))
  }

  def patch(f: AbstractFile, d: Diff): Array[Char] = {
    val (start, end, replacement) = d
    val patched = sourceFilesSeen(f).patch(start, replacement, end - start)
    sourceFilesSeen(f) = patched
    patched
  }

  implicit lazy val sourceFile: Pickler[SourceFile] =
    (pkl[AbstractFile] ~ pkl[Diff]).wrapped[SourceFile] {
      case f ~ d => new BatchSourceFile(f, patch(f, d))
    } {
      f => f.file ~ delta(f.file, f.content)
    }.asClass (classOf[BatchSourceFile])

  lazy val offsetPosition: CondPickler[Position] =
    (pkl[SourceFile] ~ pkl[Int])
      .wrapped { case x ~ y => Position.offset(x, y) } { p => p.source ~ p.point }
      .asClass (classOf[Position])

  lazy val rangePosition: CondPickler[Position] =
    (pkl[SourceFile] ~ pkl[Int] ~ pkl[Int] ~ pkl[Int])
      .wrapped { case source ~ start ~ point ~ end => Position.range(source, start, point, end) } { p => p.source ~ p.start ~ p.point ~ p.end }
      .asClass (classOf[Position])

  lazy val transparentPosition: CondPickler[Position] =
    (pkl[SourceFile] ~ pkl[Int] ~ pkl[Int] ~ pkl[Int])
      .wrapped { case source ~ start ~ point ~ end => Position.range(source, start, point, end).makeTransparent } { p => p.source ~ p.start ~ p.point ~ p.end }
      .asClass (classOf[Position])

  lazy val noPosition = singletonPickler(NoPosition)

  implicit lazy val position: Pickler[Position] = transparentPosition | rangePosition | offsetPosition | noPosition

  implicit lazy val namePickler: Pickler[Name] =
    pkl[String] .wrapped[Name] {
      str => if ((str.length > 1) && (str endsWith "!")) newTypeName(str.init) else newTermName(str)
    } {
      name => if (name.isTypeName) name.toString+"!" else name.toString
    }

  implicit lazy val symPickler: Pickler[Symbol] = {
    def ownerNames(sym: Symbol, buf: ListBuffer[Name]): ListBuffer[Name] = {
      if (!sym.isRoot) {
        ownerNames(sym.owner, buf)
        buf += (if (sym.isModuleClass) sym.sourceModule else sym).name
        if (!sym.isType && !sym.isStable) { // TODO: what's the reasoning behind this condition!?
          val sym1 = sym.owner.info.decl(sym.name)
          if (sym1.isOverloaded) {
            val index = sym1.alternatives.indexOf(sym)
            assert(index >= 0, sym1+" not found in alternatives "+sym1.alternatives)
            buf += newTermName(index.toString)
          }
        }
      }
      buf
    }
    def makeSymbol(root: Symbol, names: List[Name]): Symbol = names match {
      case List() =>
        root
      case name :: rest =>
        val sym = root.info.decl(name)
        if (sym.isOverloaded) makeSymbol(sym.alternatives(rest.head.toString.toInt), rest.tail)
        else makeSymbol(sym, rest)
    }
    pkl[List[Name]] .wrapped { makeSymbol(rootMirror.RootClass, _) } { ownerNames(_, new ListBuffer).toList }
  }

  implicit def workEvent: Pickler[WorkEvent] = {
    (pkl[Int] ~ pkl[Long])
      .wrapped { case id ~ ms => WorkEvent(id, ms) } { w => w.atNode ~ w.atMillis }
  }

  implicit def interruptReq: Pickler[InterruptReq] = {
    val emptyIR: InterruptReq = new InterruptReq { type R = Unit; val todo = () => () }
    pkl[Unit] .wrapped { _ =>  emptyIR } { _ => () }
  }

  implicit def reloadItem: CondPickler[ReloadItem] =
    pkl[List[SourceFile]]
      .wrapped { ReloadItem(_, new Response) } { _.sources }
      .asClass (classOf[ReloadItem])

  implicit def askTypeAtItem: CondPickler[AskTypeAtItem] =
    pkl[Position]
      .wrapped { new AskTypeAtItem(_, new Response) } { _.pos }
      .asClass (classOf[AskTypeAtItem])

  implicit def askTypeItem: CondPickler[AskTypeItem] =
    (pkl[SourceFile] ~ pkl[Boolean])
      .wrapped { case source ~ forceReload => new AskTypeItem(source, forceReload, new Response) } { w => w.source ~ w.forceReload }
      .asClass (classOf[AskTypeItem])

  implicit def askTypeCompletionItem: CondPickler[AskTypeCompletionItem] =
    pkl[Position]
      .wrapped { new AskTypeCompletionItem(_, new Response) } { _.pos }
      .asClass (classOf[AskTypeCompletionItem])

  implicit def askScopeCompletionItem: CondPickler[AskScopeCompletionItem] =
    pkl[Position]
      .wrapped { new AskScopeCompletionItem(_, new Response) } { _.pos }
      .asClass (classOf[AskScopeCompletionItem])

  implicit def askToDoFirstItem: CondPickler[AskToDoFirstItem] =
    pkl[SourceFile]
      .wrapped { new AskToDoFirstItem(_) } { _.source }
      .asClass (classOf[AskToDoFirstItem])

  implicit def askLinkPosItem: CondPickler[AskLinkPosItem] =
    (pkl[Symbol] ~ pkl[SourceFile])
      .wrapped { case sym ~ source => new AskLinkPosItem(sym, source, new Response) } { item => item.sym ~ item.source }
      .asClass (classOf[AskLinkPosItem])

  implicit def askDocCommentItem: CondPickler[AskDocCommentItem] =
    (pkl[Symbol] ~ pkl[SourceFile] ~ pkl[Symbol] ~ pkl[List[(Symbol,SourceFile)]])
      .wrapped { case sym ~ source ~ site ~ fragments => new AskDocCommentItem(sym, source, site, fragments, new Response) } { item => item.sym ~ item.source ~ item.site ~ item.fragments }
      .asClass (classOf[AskDocCommentItem])

  implicit def askLoadedTypedItem: CondPickler[AskLoadedTypedItem] =
    pkl[SourceFile]
      .wrapped { source => new AskLoadedTypedItem(source, false, new Response) } { _.source }
      .asClass (classOf[AskLoadedTypedItem])

  implicit def askParsedEnteredItem: CondPickler[AskParsedEnteredItem] =
    (pkl[SourceFile] ~ pkl[Boolean])
      .wrapped { case source ~ keepLoaded => new AskParsedEnteredItem(source, keepLoaded, new Response) } { w => w.source ~ w.keepLoaded }
      .asClass (classOf[AskParsedEnteredItem])

  implicit def emptyAction: CondPickler[EmptyAction] =
    pkl[Unit]
      .wrapped { _ => new EmptyAction } { _ => () }
      .asClass (classOf[EmptyAction])

  implicit def action: Pickler[() => Unit] =
    reloadItem | askTypeAtItem | askTypeItem | askTypeCompletionItem | askScopeCompletionItem |
    askToDoFirstItem | askLinkPosItem | askDocCommentItem | askLoadedTypedItem | askParsedEnteredItem | emptyAction
}