Scala example source code file (Scalac.scala)

This example Scala source code file (Scalac.scala) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Scala tags/keywords

boolean, file, io, list, list, none, none, option, option, path, reference, settings, some, string, string

The Scala Scalac.scala source code

/*                     __                                               *\
**     ________ ___   / /  ___     Scala Ant Tasks                      **
**    / __/ __// _ | / /  / _ |    (c) 2005-2011, LAMP/EPFL             **
**  __\ \/ /__/ __ |/ /__/ __ |    http://scala-lang.org/               **
** /____/\___/_/ |_/____/_/ | |                                         **
**                          |/                                          **
\*                                                                      */


package scala.tools.ant

import java.io.{File,PrintWriter,BufferedWriter,FileWriter}

import org.apache.tools.ant.{ BuildException, Project, AntClassLoader }
import org.apache.tools.ant.taskdefs.Java
import org.apache.tools.ant.types.{Path, Reference}
import org.apache.tools.ant.util.{FileUtils, GlobPatternMapper,
                                  SourceFileScanner}

import scala.tools.nsc.{Global, Settings, CompilerCommand}
import scala.tools.nsc.reporters.{Reporter, ConsoleReporter}

/** <p>
 *    An Ant task to compile with the new Scala compiler (NSC).
 *  </p>
 *  <p>
 *    This task can take the following parameters as attributes:
 *  </p>
 *  <ul style="font-family:Courier;">
 *    <li>srcdir (mandatory),
 *    <li>srcref,
 *    <li>destdir,
 *    <li>classpath,
 *    <li>classpathref,
 *    <li>sourcepath,
 *    <li>sourcepathref,
 *    <li>bootclasspath,
 *    <li>bootclasspathref,
 *    <li>extdirs,
 *    <li>extdirsref,
 *    <li>encoding,
 *    <li>target,
 *    <li>force,
 *    <li>fork, 
 *    <li>logging,
 *    <li>logphase,
 *    <li>debuginfo,
 *    <li>addparams,
 *    <li>scalacdebugging,
 *    <li>deprecation,
 *    <li>optimise,
 *    <li>unchecked,
 *    <li>failonerror,
 *    <li>scalacdebugging,
 *    <li>assemname,
 *    <li>assemrefs.
 *  </ul>
 *  <p>
 *    It also takes the following parameters as nested elements:
 *  </p>
 *  <ul>
 *    <li>src (for srcdir),
 *    <li>classpath,
 *    <li>sourcepath,
 *    <li>bootclasspath,
 *    <li>extdirs.
 * </ul>
 *
 * @author Gilles Dubochet, Stephane Micheloud
 */
class Scalac extends ScalaMatchingTask with ScalacShared {

  /** The unique Ant file utilities instance to use in this task. */
  private val fileUtils = FileUtils.getFileUtils()

/*============================================================================*\
**                             Ant user-properties                            **
\*============================================================================*/

  abstract class PermissibleValue {
    val values: List[String]
    def isPermissible(value: String): Boolean =
      (value == "") || values.exists(_.startsWith(value))
  }

  /** Defines valid values for the logging property. */
  object LoggingLevel extends PermissibleValue {
    val values = List("none", "verbose", "debug")
  }

  /** Defines valid values for properties that refer to compiler phases. */
  object CompilerPhase extends PermissibleValue {
    val values = List("namer", "typer", "pickler", "uncurry", "tailcalls",
                      "explicitouter", "erasure", "lambdalift",
                      "flatten", "constructors", "mixin", "icode", "jvm",
                      "terminal")
  }

  /** Defines valid values for the <code>target property. */
  object Target extends PermissibleValue {
    val values = List("jvm-1.5", "msil")
  }

  /** Defines valid values for the <code>deprecation and
   *  <code>unchecked properties. */
  object Flag extends PermissibleValue {
    val values = List("yes", "no", "on", "off", "true", "false")
    def toBoolean(flag: String) =
      if (flag == "yes" || flag == "on" || flag == "true") Some(true)
      else if (flag == "no" || flag == "off" || flag == "false") Some(false)
      else None
  }

  /** The directories that contain source files to compile. */
  protected var origin: Option[Path] = None
  /** The directory to put the compiled files in. */
  protected var destination: Option[File] = None

  /** The class path to use for this compilation. */
  protected var classpath: Option[Path] = None
  /** The source path to use for this compilation. */
  protected var sourcepath: Option[Path] = None
  /** The boot class path to use for this compilation. */
  protected var bootclasspath: Option[Path] = None
  /** The path to use when finding scalac - *only used for forking!*  */
  protected var compilerPath: Option[Path] = None
  /** The external extensions path to use for this compilation. */
  protected var extdirs: Option[Path] = None

  /** The character encoding of the files to compile. */
  protected var encoding: Option[String] = None

  // the targetted backend
  protected var backend: Option[String] = None

  /** Whether to force compilation of all files or not. */
  protected var force: Boolean = false
  /** Whether to fork the execution of scalac */
  protected var fork : Boolean = false
  /** If forking, these are the arguments to the JVM */
  protected var jvmArgs : Option[String] = None
  /** How much logging output to print. Either none (default),
    * verbose or debug. */
  protected var logging: Option[String] = None
  /** Which compilation phases should be logged during compilation. */
  protected var logPhase: List[String] = Nil

  /** Instruct the compiler to generate debugging information */
  protected var debugInfo: Option[String] = None
  /** Instruct the compiler to use additional parameters */
  protected var addParams: String = ""
  /** Instruct the compiler to generate deprecation information. */
  protected var deprecation: Option[Boolean] = None
  /** Instruct the compiler to run optimizations. */
  protected var optimise: Option[Boolean] = None
  /** Instruct the compiler to generate unchecked information. */
  protected var unchecked: Option[Boolean] = None
  /** Indicates whether compilation errors will fail the build; defaults to true. */
  protected var failonerror: Boolean = true

  // Name of the output assembly (only relevant with -target:msil)
  protected var assemname: Option[String] = None
  // List of assemblies referenced by the program (only relevant with -target:msil)
  protected var assemrefs: Option[String] = None

  /** Prints out the files being compiled by the scalac ant task
   *  (not only the number of files). */
  protected var scalacDebugging: Boolean = false
  
  /** Helpers */
  private def setOrAppend(old: Option[Path], arg: Path): Option[Path] = old match {
    case Some(x)  => x append arg ; Some(x)
    case None     => Some(arg)
  }
  private def pathAsList(p: Option[Path], name: String): List[File] = p match {
    case None     => buildError("Member '" + name + "' is empty.")
    case Some(x)  => x.list.toList map nameToFile
  }
  private def createNewPath(getter: () => Option[Path], setter: (Option[Path]) => Unit) = {
    if (getter().isEmpty)
      setter(Some(new Path(getProject())))
 
    getter().get.createPath()
  }
      
  private def plural(xs: List[Any]) = if (xs.size > 1) "s" else ""
  private def plural(x: Int) = if (x > 1) "s" else ""

/*============================================================================*\
**                             Properties setters                             **
\*============================================================================*/


  /** Sets the srcdir attribute. Used by Ant.
   *  @param input The value of <code>origin. */
  def setSrcdir(input: Path) {
    origin = setOrAppend(origin, input)
  }

  /** Sets the <code>origin as a nested src Ant parameter.
   *  @return An origin path to be configured. */
  def createSrc(): Path = createNewPath(origin _, p => origin = p)

  /** Sets the <code>origin as an external reference Ant parameter.
   *  @param input A reference to an origin path. */
  def setSrcref(input: Reference) =
    createSrc().setRefid(input)

  /** Sets the <code>destdir attribute. Used by Ant.
   *  @param input The value of <code>destination. */
  def setDestdir(input: File) { destination = Some(input) }

  /** Sets the <code>classpath attribute. Used by Ant.
   *  @param input The value of <code>classpath. */
  def setClasspath(input: Path) {
    classpath = setOrAppend(classpath, input)
  }
  /** Sets the <code>compilerPath attribute. Used by Ant.
   *  @param input The value of <code>compilerPath. */
  def setCompilerPath(input : Path) {
    compilerPath = setOrAppend(compilerPath, input)
  }
  
  def createCompilerPath: Path = createNewPath(compilerPath _, p => compilerPath = p)

  /** Sets the <code>compilerpathref attribute. Used by Ant.
   *  @param input The value of <code>compilerpathref. */
  def setCompilerPathRef(input: Reference) {
    createCompilerPath.setRefid(input)
  }

  /** Sets the <code>classpath as a nested classpath Ant parameter.
   *  @return A class path to be configured. */
  def createClasspath(): Path = createNewPath(classpath _, p => classpath = p)

  /** Sets the <code>classpath as an external reference Ant parameter.
   *  @param input A reference to a class path. */
  def setClasspathref(input: Reference) {
    createClasspath().setRefid(input)
  }

  /** Sets the <code>sourcepath attribute. Used by Ant.
   *  @param input The value of <code>sourcepath. */
  def setSourcepath(input: Path) {
    sourcepath = setOrAppend(sourcepath, input)
  }

  /** Sets the <code>sourcepath as a nested sourcepath Ant parameter.
   *  @return A source path to be configured. */
  def createSourcepath(): Path = createNewPath(sourcepath _, p => sourcepath = p)

  /** Sets the <code>sourcepath as an external reference Ant parameter.
   *  @param input A reference to a source path. */
  def setSourcepathref(input: Reference) {
    createSourcepath().setRefid(input)
  }

  /** Sets the boot classpath attribute. Used by Ant.
   *
   *  @param input The value of <code>bootclasspath. */
  def setBootclasspath(input: Path) {
    bootclasspath = setOrAppend(bootclasspath, input)
  }

  /** Sets the <code>bootclasspath as a nested sourcepath Ant
   *  parameter.
   *  @return A source path to be configured. */
  def createBootclasspath(): Path = createNewPath(bootclasspath _, p => bootclasspath = p)

  /** Sets the <code>bootclasspath as an external reference Ant
   *  parameter.
   *  @param input A reference to a source path. */
  def setBootclasspathref(input: Reference) =
    createBootclasspath().setRefid(input)

  /** Sets the external extensions path attribute. Used by Ant.
   *  @param input The value of <code>extdirs. */
  def setExtdirs(input: Path) =
    extdirs = setOrAppend(extdirs, input)

  /** Sets the <code>extdirs as a nested sourcepath Ant parameter.
   *  @return An extensions path to be configured. */
  def createExtdirs(): Path = createNewPath(extdirs _, p => extdirs = p)

  /** Sets the <code>extdirs as an external reference Ant parameter.
   *  @param input A reference to an extensions path. */
  def setExtdirsref(input: Reference) =
    createExtdirs().setRefid(input)

  /** Sets the <code>encoding attribute. Used by Ant.
   *  @param input The value of <code>encoding. */
  def setEncoding(input: String): Unit =
    encoding = Some(input)

  /** Sets the <code>target attribute. Used by Ant.
   *  @param input The value for <code>target. */
  def setTarget(input: String): Unit =
    if (Target.isPermissible(input)) backend = Some(input)
    else buildError("Unknown target '" + input + "'")

  /** Sets the <code>force attribute. Used by Ant.
   *  @param input The value for <code>force. */
  def setForce(input: Boolean) { force = input }
  
  /** Sets the <code>fork attribute. Used by Ant.
   *  @param input The value for <code>fork. */
  def setFork(input : Boolean) { fork = input }
  /**
   * Sets the <code>jvmargs attribute.  Used by Ant.
   * @param input The value for <code>jvmargs
   */
  def setJvmargs(input : String) {
    jvmArgs = Some(input)
  }
  
  /** Sets the logging level attribute. Used by Ant.
   *  @param input The value for <code>logging. */
  def setLogging(input: String) {
    if (LoggingLevel.isPermissible(input)) logging = Some(input)
    else buildError("Logging level '" + input + "' does not exist.")
  }

  /** Sets the <code>logphase attribute. Used by Ant.
   *  @param input The value for <code>logPhase. */
  def setLogPhase(input: String) {
    logPhase = input.split(",").toList.flatMap { s: String =>
      val st = s.trim()
      if (CompilerPhase.isPermissible(st))
        (if (input != "") List(st) else Nil)
      else {
        buildError("Phase " + st + " in log does not exist.")
      }
    }
  }

  /** Set the <code>debug info attribute.
   *  @param input The value for <code>debug. */
  def setDebuginfo(input: String) { debugInfo = Some(input) }

  /** Set the <code>addparams info attribute.
   *  @param input The value for <code>addparams. */
  def setAddparams(input: String) { addParams = input }

  /** Set the <code>deprecation info attribute.
   *  @param input One of the flags <code>yes/no or on/off. */
  def setDeprecation(input: String) {
    deprecation = Flag toBoolean input orElse buildError("Unknown deprecation flag '" + input + "'")
  }

  /** Set the <code>optimise info attribute.
   *  @param input One of the flags <code>yes/no or on/off. */
  def setOptimise(input: String) {
    optimise = Flag toBoolean input orElse buildError("Unknown optimisation flag '" + input + "'")
  }

  /** Set the <code>unchecked info attribute.
   *  @param input One of the flags <code>yes/no or on/off. */
  def setUnchecked(input: String) {
    unchecked = Flag toBoolean input orElse buildError("Unknown unchecked flag '" + input + "'")
  }

  /** Sets the <code>force attribute. Used by Ant.
   *  @param input The value for <code>force. */
  def setFailonerror(input: Boolean) { failonerror = input }

  /** Set the <code>scalacdebugging info attribute. If set to
   *  <code>true, the scalac ant task will print out the filenames
   *  being compiled.
   *  @param input The specified flag */
  def setScalacdebugging(input: Boolean) { scalacDebugging = input }

  def setAssemname(input: String) { assemname = Some(input) }
  def setAssemrefs(input: String) { assemrefs = Some(input) }

/*============================================================================*\
**                             Properties getters                             **
\*============================================================================*/

  /** Gets the value of the <code>classpath attribute in a
   *  Scala-friendly form.
   *  @return The class path as a list of files. */
  protected def getClasspath: List[File] = pathAsList(classpath, "classpath")

  /** Gets the value of the <code>origin attribute in a
   *  Scala-friendly form.
   *  @return The origin path as a list of files. */
  protected def getOrigin: List[File] = pathAsList(origin, "origin")

  /** Gets the value of the <code>destination attribute in a
   *  Scala-friendly form.
   *  @return The destination as a file. */
  protected def getDestination: File =
    if (destination.isEmpty) buildError("Member 'destination' is empty.")
    else existing(getProject().resolveFile(destination.get.toString))

  /** Gets the value of the <code>sourcepath attribute in a
   *  Scala-friendly form.
   *  @return The source path as a list of files. */
  protected def getSourcepath: List[File] = pathAsList(sourcepath, "sourcepath")

  /** Gets the value of the <code>bootclasspath attribute in a
   *  Scala-friendly form.
   *  @return The boot class path as a list of files. */
  protected def getBootclasspath: List[File] = pathAsList(bootclasspath, "bootclasspath")

  /** Gets the value of the <code>extdirs attribute in a
   *  Scala-friendly form.
   *  @return The extensions path as a list of files. */
  protected def getExtdirs: List[File] = pathAsList(extdirs, "extdirs")

/*============================================================================*\
**                       Compilation and support methods                      **
\*============================================================================*/

  /** Transforms a string name into a file relative to the provided base
   *  directory.
   *  @param base A file pointing to the location relative to which the name
   *              will be resolved.
   *  @param name A relative or absolute path to the file as a string.
   *  @return     A file created from the name and the base file. */
  protected def nameToFile(base: File)(name: String): File =
    existing(fileUtils.resolveFile(base, name))

  /** Transforms a string name into a file relative to the build root
   *  directory.
   *  @param name A relative or absolute path to the file as a string.
   *  @return     A file created from the name. */
  protected def nameToFile(name: String): File =
    existing(getProject().resolveFile(name))

  /** Tests if a file exists and prints a warning in case it doesn't. Always
   *  returns the file, even if it doesn't exist.
   *  @param file A file to test for existance.
   *  @return     The same file. */
  protected def existing(file: File): File = {
    if (!file.exists())
      log("Element '" + file.toString + "' does not exist.",
          Project.MSG_WARN)
    file
  }

  /** Transforms a path into a Scalac-readable string.
   *  @param path A path to convert.
   *  @return     A string-representation of the path like <code>a.jar:b.jar. */
  protected def asString(path: List[File]): String =
    path.map(asString).mkString(File.pathSeparator)

  /** Transforms a file into a Scalac-readable string.
   *  @param path A file to convert.
   *  @return     A string-representation of the file like <code>/x/k/a.scala. */
  protected def asString(file: File): String =
    file.getAbsolutePath()

/*============================================================================*\
**                      Hooks for variants of Scala                           **
\*============================================================================*/

  protected def newSettings(error: String=>Unit): Settings =
    new Settings(error)
  protected def newGlobal(settings: Settings, reporter: Reporter) =
    new Global(settings, reporter)


/*============================================================================*\
**                           The big execute method                           **
\*============================================================================*/

  /** Initializes settings and source files */
  protected def initialize: (Settings, List[File], Boolean) = {
    if (scalacDebugging)
      log("Base directory is `%s`".format(scala.tools.nsc.io.Path("").normalize))

    // Tests if all mandatory attributes are set and valid.
    if (origin.isEmpty) buildError("Attribute 'srcdir' is not set.")
    if (!destination.isEmpty && !destination.get.isDirectory())
      buildError("Attribute 'destdir' does not refer to an existing directory.")
    if (destination.isEmpty) destination = Some(getOrigin.head)

    val mapper = new GlobPatternMapper()
    mapper setTo "*.class"
    mapper setFrom "*.scala"
    
    var javaOnly = true
    
    def getOriginFiles(originDir: File) = {
      val includedFiles = getDirectoryScanner(originDir).getIncludedFiles()
      val javaFiles = includedFiles filter (_ endsWith ".java")
      val scalaFiles = {
        val xs = includedFiles filter (_ endsWith ".scala")
        if (force) xs
        else new SourceFileScanner(this).restrict(xs, originDir, destination.get, mapper)
      }

      javaOnly = javaOnly && (scalaFiles.length == 0)
      val list = (scalaFiles ++ javaFiles).toList

      if (scalacDebugging && !list.isEmpty)
        log("Compiling source file%s: %s to %s".format(
          plural(list),
          list.mkString(", "),
          getDestination.toString
        ))
      else if (!list.isEmpty) {
        val str =
          if (javaFiles.isEmpty) "%d source file%s".format(list.length, plural(list))
          else "%d scala and %d java source files".format(scalaFiles.length, javaFiles.length)
        log("Compiling %s to %s".format(str, getDestination.toString))
      }
      else log("No files selected for compilation", Project.MSG_VERBOSE)
      
      list
    }
    
    // Scans source directories to build up a compile lists.
    // If force is false, only files were the .class file in destination is
    // older than the .scala file will be used.
    val sourceFiles: List[File] =
      for (originDir <- getOrigin ; originFile <- getOriginFiles(originDir)) yield {
        log(originFile, Project.MSG_DEBUG)
        nameToFile(originDir)(originFile)
      }

    // Builds-up the compilation settings for Scalac with the existing Ant
    // parameters.
    val settings = newSettings(buildError)
    settings.outdir.value = asString(destination.get)
    if (!classpath.isEmpty)
      settings.classpath.value = asString(getClasspath)
    if (!sourcepath.isEmpty)
      settings.sourcepath.value = asString(getSourcepath)
    else if (origin.get.size() > 0)
      settings.sourcepath.value = origin.get.list()(0)
    if (!bootclasspath.isEmpty)
      settings.bootclasspath.value = asString(getBootclasspath)
    if (!extdirs.isEmpty) settings.extdirs.value = asString(getExtdirs)
    if (!encoding.isEmpty) settings.encoding.value = encoding.get
    if (!backend.isEmpty) settings.target.value = backend.get
    if (!logging.isEmpty && logging.get == "verbose")
      settings.verbose.value = true
    else if (!logging.isEmpty && logging.get == "debug") {
      settings.verbose.value = true
      settings.debug.value = true
    }
    if (!logPhase.isEmpty) settings.log.value = logPhase
    if (!debugInfo.isEmpty) settings.debuginfo.value = debugInfo.get
    if (!deprecation.isEmpty) settings.deprecation.value = deprecation.get
    if (!optimise.isEmpty) settings.XO.value = optimise.get
    if (!unchecked.isEmpty) settings.unchecked.value = unchecked.get

    if (!assemname.isEmpty) settings.assemname.value = assemname.get
    if (!assemrefs.isEmpty) settings.assemrefs.value = assemrefs.get

    log("Scalac params = '" + addParams + "'", Project.MSG_DEBUG)

    // let CompilerCommand processes all params
    val command = new CompilerCommand(settings.splitParams(addParams), settings)

    // resolve dependenciesFile path from project's basedir, so <ant antfile ...> call from other project works.
    // the dependenciesFile may be relative path to basedir or absolute path, in either case, the following code
    // will return correct answer.
    command.settings.dependenciesFile.value match {
      case "none" =>
      case x =>
        val depFilePath = scala.tools.nsc.io.Path(x)
        command.settings.dependenciesFile.value = scala.tools.nsc.io.Path(getProject.getBaseDir).normalize resolve depFilePath path
    }

    (command.settings, sourceFiles, javaOnly)
  }

  override def execute() {
    val (settings, sourceFiles, javaOnly) = initialize
    if (sourceFiles.isEmpty || javaOnly)
      return
      
    if (fork) executeFork(settings, sourceFiles)  // TODO - Error
    else executeInternal(settings, sourceFiles)
  }
  
  protected def executeFork(settings: Settings, sourceFiles: List[File]) {
      val java = new Java(this)
      java setFork true
      // using 'setLine' creates multiple arguments out of a space-separated string
      jvmArgs foreach { java.createJvmarg() setLine _ }

      // use user-provided path or retrieve from classloader
      // TODO - Allow user to override the compiler classpath
      val scalacPath: Path = {
        val path = new Path(getProject)
        if (compilerPath.isDefined) path add compilerPath.get
        else getClass.getClassLoader match {
          case cl: AntClassLoader => path add new Path(getProject, cl.getClasspath)
          case _                  => buildError("Cannot determine default classpath for scalac, please specify one!")
        }
        path
      }
      
      java setClasspath scalacPath
      java setClassname MainClass

      // Write all settings to a temporary file
      def writeSettings() : File = {
        def escapeArgument(arg : String) = if(arg.matches(".*\\s.*")) ('"' + arg + '"') else arg
        val file = File.createTempFile("scalac-ant-",".args")
        file.deleteOnExit()
        val out = new PrintWriter(new BufferedWriter(new FileWriter(file)))
        
        try {
          for (setting <- settings.visibleSettings ; arg <- setting.unparse)
            out println escapeArgument(arg)
          for (file <- sourceFiles)
            out println escapeArgument(file.getAbsolutePath)
        }
        finally out.close()
        
        file
      }
      val res = execWithArgFiles(java, List(writeSettings.getAbsolutePath))
      if (failonerror && res != 0)
        buildError("Compilation failed because of an internal compiler error;"+
              " see the error output for details.")
  }
  
  /** Performs the compilation. */
  protected def executeInternal(settings: Settings, sourceFiles : List[File]) {
    val reporter = new ConsoleReporter(settings)
    val compiler = newGlobal(settings, reporter)  // compiles the actual code
    
    try new compiler.Run compile (sourceFiles map (_.toString))
    catch {
      case ex: Throwable =>
        ex.printStackTrace()
        val msg = if (ex.getMessage == null) "no error message provided" else ex.getMessage
        buildError("Compile failed because of an internal compiler error (" + msg + "); see the error output for details.")
    }

    reporter.printSummary()
    if (reporter.hasErrors) {
      val msg = "Compile failed with %d error%s; see the compiler error output for details.".format(
        reporter.ERROR.count, plural(reporter.ERROR.count))
      if (failonerror) buildError(msg) else log(msg)
    }
    else if (reporter.WARNING.count > 0)
      log("Compile succeeded with %d warning%s; see the compiler output for details.".format(
        reporter.WARNING.count, plural(reporter.WARNING.count)))
  }
}