Fix #2186: Synchronize classpath handling with Scala 2.12

This commit is a very crude port of the classpath handling as it exists
in the 2.12.x branch of scalac (hash: 232d95a198c94da0c6c8393624e83e9b9ac84e81),
this replaces the existing Classpath code that was adapted from scalac
years ago.

This code was written by Grzegorz Kossakowski, Michał Pociecha, Lukas
Rytz, Jason Zaugg and other scalac contributors, many thanks to them!

For more information on this implementation, see the description of the
PR that originally added it to scalac: https://github.com/scala/scala/pull/4060

Changes made to the copied code to get it to compile with dotty:
- Rename scala.tools.nsc.util.ClassPath to dotty.tools.io.ClassPath
- Rename scala.tools.nsc.classpath.* to dotty.tools.dotc.classpath.*
- Replace "private[nsc]" by "private[dotty]"
- Changed `isClass` methods in FileUtils to skip Scala 2.11
  implementation classes (needed until we stop being retro-compatible with
  Scala 2.11)

I also copied PlainFile.scala from scalac to get access to
`PlainNioFile`.

1 files changed, 170 insertions, 0 deletions

diff --git a/compiler/src/dotty/tools/io/PlainFile.scala b/compiler/src/dotty/tools/io/PlainFile.scala
new file mode 100644
index 000000000..53474e778
--- /dev/null
+++ b/compiler/src/dotty/tools/io/PlainFile.scala
@@ -0,0 +1,170 @@
+/* NSC -- new Scala compiler
+ * Copyright 2005-2013 LAMP/EPFL
+ * @author  Martin Odersky
+ */
+
+package dotty.tools
+package io
+
+/** ''Note:  This library is considered experimental and should not be used unless you know what you are doing.'' */
+class PlainDirectory(givenPath: Directory) extends PlainFile(givenPath) {
+  override def isDirectory = true
+  override def iterator = givenPath.list filter (_.exists) map (x => new PlainFile(x))
+  override def delete(): Unit = givenPath.deleteRecursively()
+}
+
+/** This class implements an abstract file backed by a File.
+ *
+ * ''Note:  This library is considered experimental and should not be used unless you know what you are doing.''
+ */
+class PlainFile(val givenPath: Path) extends AbstractFile {
+  assert(path ne null)
+
+  val file = givenPath.jfile
+  override def underlyingSource = Some(this)
+
+  private val fpath = givenPath.toAbsolute
+
+  /** Returns the name of this abstract file. */
+  def name = givenPath.name
+
+  /** Returns the path of this abstract file. */
+  def path = givenPath.path
+
+  /** The absolute file. */
+  def absolute = new PlainFile(givenPath.toAbsolute)
+
+  override def container: AbstractFile = new PlainFile(givenPath.parent)
+  override def input = givenPath.toFile.inputStream()
+  override def output = givenPath.toFile.outputStream()
+  override def sizeOption = Some(givenPath.length.toInt)
+
+  override def hashCode(): Int = fpath.hashCode()
+  override def equals(that: Any): Boolean = that match {
+    case x: PlainFile => fpath == x.fpath
+    case _            => false
+  }
+
+  /** Is this abstract file a directory? */
+  def isDirectory: Boolean = givenPath.isDirectory
+
+  /** Returns the time that this abstract file was last modified. */
+  def lastModified: Long = givenPath.lastModified
+
+  /** Returns all abstract subfiles of this abstract directory. */
+  def iterator: Iterator[AbstractFile] = {
+    // Optimization: Assume that the file was not deleted and did not have permissions changed
+    // between the call to `list` and the iteration. This saves a call to `exists`.
+    def existsFast(path: Path) = path match {
+      case (_: Directory | _: io.File) => true
+      case _                           => path.exists
+    }
+    if (!isDirectory) Iterator.empty
+    else givenPath.toDirectory.list filter existsFast map (new PlainFile(_))
+  }
+
+  /**
+   * Returns the abstract file in this abstract directory with the
+   * specified name. If there is no such file, returns null. The
+   * argument "directory" tells whether to look for a directory or
+   * or a regular file.
+   */
+  def lookupName(name: String, directory: Boolean): AbstractFile = {
+    val child = givenPath / name
+    if ((child.isDirectory && directory) || (child.isFile && !directory)) new PlainFile(child)
+    else null
+  }
+
+  /** Does this abstract file denote an existing file? */
+  def create(): Unit = if (!exists) givenPath.createFile()
+
+  /** Delete the underlying file or directory (recursively). */
+  def delete(): Unit =
+    if (givenPath.isFile) givenPath.delete()
+    else if (givenPath.isDirectory) givenPath.toDirectory.deleteRecursively()
+
+  /** Returns a plain file with the given name. It does not
+   *  check that it exists.
+   */
+  def lookupNameUnchecked(name: String, directory: Boolean): AbstractFile =
+    new PlainFile(givenPath / name)
+}
+
+private[dotty] class PlainNioFile(nioPath: java.nio.file.Path) extends AbstractFile {
+  import java.nio.file._
+
+  assert(nioPath ne null)
+
+  /** Returns the underlying File if any and null otherwise. */
+  override def file: java.io.File = try {
+    nioPath.toFile
+  } catch {
+    case _: UnsupportedOperationException => null
+  }
+
+  override def underlyingSource  = Some(this)
+
+  private val fpath = nioPath.toAbsolutePath.toString
+
+  /** Returns the name of this abstract file. */
+  def name = nioPath.getFileName.toString
+
+  /** Returns the path of this abstract file. */
+  def path = nioPath.toString
+
+  /** The absolute file. */
+  def absolute = new PlainNioFile(nioPath.toAbsolutePath)
+
+  override def container: AbstractFile = new PlainNioFile(nioPath.getParent)
+  override def input = Files.newInputStream(nioPath)
+  override def output = Files.newOutputStream(nioPath)
+  override def sizeOption = Some(Files.size(nioPath).toInt)
+  override def hashCode(): Int = fpath.hashCode()
+  override def equals(that: Any): Boolean = that match {
+    case x: PlainNioFile => fpath == x.fpath
+    case _               => false
+  }
+
+  /** Is this abstract file a directory? */
+  def isDirectory: Boolean = Files.isDirectory(nioPath)
+
+  /** Returns the time that this abstract file was last modified. */
+  def lastModified: Long = Files.getLastModifiedTime(nioPath).toMillis
+
+  /** Returns all abstract subfiles of this abstract directory. */
+  def iterator: Iterator[AbstractFile] = {
+    try {
+      import scala.collection.JavaConverters._
+      val it = Files.newDirectoryStream(nioPath).iterator()
+      it.asScala.map(new PlainNioFile(_))
+    } catch {
+      case _: NotDirectoryException => Iterator.empty
+    }
+  }
+
+  /**
+    * Returns the abstract file in this abstract directory with the
+    * specified name. If there is no such file, returns null. The
+    * argument "directory" tells whether to look for a directory or
+    * or a regular file.
+    */
+  def lookupName(name: String, directory: Boolean): AbstractFile = {
+    val child = nioPath.resolve(name)
+    if ((Files.isDirectory(child) && directory) || (Files.isRegularFile(child) && !directory)) new PlainNioFile(child)
+    else null
+  }
+
+  /** Does this abstract file denote an existing file? */
+  def create(): Unit = if (!exists)  Files.createFile(nioPath)
+
+  /** Delete the underlying file or directory (recursively). */
+  def delete(): Unit =
+    if (Files.isRegularFile(nioPath)) Files.deleteIfExists(nioPath)
+    else if (Files.isDirectory(nioPath)) new Directory(nioPath.toFile).deleteRecursively()
+
+  /** Returns a plain file with the given name. It does not
+    *  check that it exists.
+    */
+  def lookupNameUnchecked(name: String, directory: Boolean): AbstractFile =
+    new PlainNioFile(nioPath.resolve(name))
+}