path: root/src/compiler/scala/tools/nsc/io/Path.scala

/* NSC -- new Scala compiler
 * Copyright 2005-2009 LAMP/EPFL
 */

package scala.tools.nsc
package io

import java.io.{
  FileInputStream, FileOutputStream, BufferedReader, BufferedWriter, InputStreamReader, OutputStreamWriter,
  BufferedInputStream, BufferedOutputStream, File => JFile }
import java.net.{ URI, URL }
import collection.{ Seq, Traversable }
import PartialFunction._
import scala.util.Random.nextASCIIString

/** An abstraction for filesystem paths.  The differences between
 *  Path, File, and Directory are primarily to communicate intent.
 *  Since the filesystem can change at any time, there is no way to
 *  reliably associate Files only with files and so on.  Any Path
 *  can be converted to a File or Directory (and thus gain access to
 *  the additional entity specific methods) by calling toFile or
 *  toDirectory, which has no effect on the filesystem.
 *
 *  Also available are createFile and createDirectory, which attempt
 *  to create the path in question.
 *
 *  @author  Paul Phillips
 *  @since   2.8
 */

object Path
{
  // not certain these won't be problematic, but looks good so far
  implicit def string2path(s: String): Path = apply(s)
  implicit def jfile2path(jfile: JFile): Path = apply(jfile)

  // java 7 style, we don't use it yet
  // object AccessMode extends Enumeration("AccessMode") {
  //   val EXECUTE, READ, WRITE = Value
  // }
  // def checkAccess(modes: AccessMode*): Boolean = {
  //   modes foreach {
  //     case EXECUTE  => throw new Exception("Unsupported") // can't check in java 5
  //     case READ     => if (!jfile.canRead()) return false
  //     case WRITE    => if (!jfile.canWrite()) return false
  //   }
  //   true
  // }

  def roots: List[Path] = JFile.listRoots().toList map Path.apply

  def apply(path: String): Path = apply(new JFile(path))
  def apply(jfile: JFile): Path =
    if (jfile.isFile) new File(jfile)
    else if (jfile.isDirectory) new Directory(jfile)
    else new Path(jfile)

  private[io] def randomPrefix = nextASCIIString(6)
  private[io] def fail(msg: String) = throw FileOperationException(msg)
}
import Path._

/** The Path constructor is private so we can enforce some
 *  semantics regarding how a Path might relate to the world.
 */
class Path private[io] (val jfile: JFile)
{
  val separator = JFile.separatorChar
  val separatorStr = JFile.separator

  // Validation: this verifies that the type of this object and the
  // contents of the filesystem are in agreement.  All objects are
  // valid except File objects whose path points to a directory and
  // Directory objects whose path points to a file.
  def isValid: Boolean = true

  // conversions
  def toFile: File = new File(jfile)
  def toDirectory: Directory = new Directory(jfile)
  def toAbsolute: Path = if (isAbsolute) this else Path(jfile.getAbsolutePath())
  def toURI: URI = jfile.toURI()
  def toURL: URL = toURI.toURL()

  /** Creates a new Path with the specified path appended.  Assumes
   *  the type of the new component implies the type of the result.
   */
  def /(child: Path): Path = new Path(new JFile(jfile, child.path))
  def /(child: Directory): Directory = /(child: Path).toDirectory
  def /(child: File): File = /(child: Path).toFile

  // identity
  def name: String = jfile.getName()
  def path: String = jfile.getPath()
  def normalize: Path = Path(jfile.getCanonicalPath())

  def resolve(other: Path) = if (other.isAbsolute || isEmpty) other else /(other)
  def relativize(other: Path) = {
    assert(isAbsolute == other.isAbsolute, "Paths not of same type: "+this+", "+other)

    def createRelativePath(baseSegs: List[String], otherSegs: List[String]) : String = {
      (baseSegs, otherSegs) match {
        case (b :: bs, o :: os) if b == o => createRelativePath(bs, os)
        case (bs, os) => ((".."+separator)*bs.length)+os.mkString(separatorStr)
      }
    }

    Path(createRelativePath(segments, other.segments))
  }

  // derived from identity
  def root: Option[Path] = roots find (this startsWith _)
  def segments: List[String] = (path split separator).toList filterNot (_.length == 0)
  def parent: Option[Path] = Option(jfile.getParent()) map Path.apply
  def parents: List[Path] = parent match {
    case None     => Nil
    case Some(p)  => p :: p.parents
  }
  // if name ends with an extension (e.g. "foo.jpg") returns the extension ("jpg"), otherwise ""
  def extension: String = (name lastIndexOf '.') match {
    case -1   => ""
    case idx  => name drop (idx + 1)
  }

  // Boolean tests
  def canRead = jfile.canRead()
  def canWrite = jfile.canWrite()
  def exists = jfile.exists()
  def notExists = try !jfile.exists() catch { case ex: SecurityException => false }

  def isFile = jfile.isFile()
  def isDirectory = jfile.isDirectory()
  def isAbsolute = jfile.isAbsolute()
  def isHidden = jfile.isHidden()
  def isSymlink = parent.isDefined && {
    val x = parent.get / name
    x.normalize != x.toAbsolute
  }
  def isEmpty = path.length == 0

  // Information
  def lastModified = jfile.lastModified()
  def lastModified_=(time: Long) = jfile setLastModified time // should use setXXX function?
  def length = jfile.length()

  // Boolean path comparisons
  def endsWith(other: Path) = segments endsWith other.segments
  def startsWith(other: Path) = segments startsWith other.segments
  def isSame(other: Path) = toAbsolute == other.toAbsolute
  def isFresher(other: Path) = lastModified > other.lastModified

  // creations
  def createDirectory(force: Boolean = true, failIfExists: Boolean = false): Directory = {
    val res = if (force) jfile.mkdirs() else jfile.mkdir()
    if (!res && failIfExists && exists) fail("Directory '%s' already exists." format name)
    else if (isDirectory) toDirectory
    else new Directory(jfile)
  }
  def createFile(failIfExists: Boolean = false): File = {
    val res = jfile.createNewFile()
    if (!res && failIfExists && exists) fail("File '%s' already exists." format name)
    else if (isFile) toFile
    else new File(jfile)
  }

  // deletions
  def delete() = jfile.delete()
  def deleteIfExists() = if (jfile.exists()) delete() else false

  // todo
  // def copyTo(target: Path, options ...): Boolean
  // def moveTo(target: Path, options ...): Boolean

  override def toString() = "Path(%s)".format(path)
  override def equals(other: Any) = other match {
    case x: Path  => path == x.path
    case _        => false
  }
  override def hashCode() = path.hashCode()
}