abstractfile.scala

来自「JAVA 语言的函数式编程扩展」· SCALA 代码 · 共 194 行

/* NSC -- new Scala compiler
 * Copyright 2005-2007 LAMP/EPFL
 * @author  Martin Odersky
 */
// $Id: AbstractFile.scala 12886 2007-09-17 16:36:10Z mcdirmid $


package scala.tools.nsc.io

import java.io.{File, IOException, InputStream}
import java.net.URL

import scala.collection.mutable.ArrayBuffer

/**
 * @author Philippe Altherr
 * @version 1.0, 23/03/2004
 */
object AbstractFile {

  /** Returns "getFile(new File(path))". */
  def getFile(path: String): AbstractFile = getFile(new File(path))

  /**
   * If the specified File exists and is a regular file, returns an
   * abstract regular file backed by it. Otherwise, returns <code>null</code>.
   */
  def getFile(file: File): AbstractFile =
    if (file.isFile() && file.exists()) new PlainFile(file) else null


  /** Returns "getDirectory(new File(path))". */
  def getDirectory(path: String): AbstractFile = getDirectory(new File(path))

  /**
   * If the specified File exists and is either a directory or a
   * readable zip or jar archive, returns an abstract directory
   * backed by it. Otherwise, returns <code>null</code>.
   *
   * @param file ...
   * @return     ...
   */
  def getDirectory(file: File): AbstractFile = {
    if (file.isDirectory() && file.exists()) return new PlainFile(file)
    if (file.isFile() && file.exists()) {
      val path = file.getPath()
      if (path.endsWith(".jar") || path.endsWith(".zip"))
        return ZipArchive.fromFile(file);
    }
    null
  }

  /**
   * If the specified URL exists and is a readable zip or jar archive,
   * returns an abstract directory backed by it. Otherwise, returns
   * <code>null</code>.
   *
   * @param file ...
   * @return     ...
   */
  def getURL(url: URL): AbstractFile =
    if (url ne null) {
      val path = url.getPath()
      if (path.endsWith(".jar") || path.endsWith(".zip"))
        ZipArchive.fromURL(url)
      else
        null
    }
    else
      null
}

/**
 * <p>
 *   This class and its children serve to unify handling of files and
 *   directories. These files and directories may or may not have some 
 *   real counter part within the file system. For example, some file
 *   handles reference files within a zip archive or virtual ones 
 *   that exist only in memory.
 * </p>
 * <p>
 *   Every abstract file has a path (i.e. a full name) and a name
 *   (i.e. a short name) and may be backed by some real File. There are
 *   two different kinds of abstract files: regular files and
 *   directories. Regular files may be read and have a last modification
 *   time. Directories may list their content and look for subfiles with
 *   a specified name or path and of a specified kind.
 * </p>
 * <p>
 *   The interface does <b>not</b> allow to access the content.
 *   The class <code>symtab.classfile.AbstractFileReader</code> accesses 
 *   bytes, knowing that the character set of classfiles is UTF-8. For 
 *   all other cases, the class <code>SourceFile</code> is used, which honors 
 *   <code>global.settings.encoding.value</code>.
 * </p>
 */
abstract class AbstractFile extends AnyRef with Iterable[AbstractFile] {

  /** Returns the name of this abstract file. */
  def name: String

  /** Returns the path of this abstract file. */
  def path: String

  /** Returns the containing directory of this abstract file */
  def container : AbstractFile
  
  /** Returns the underlying File if any and null otherwise. */
  def file: File

  /** Is this abstract file a directory? */
  def isDirectory: Boolean

  /** Returns the time that this abstract file was last modified. */
  def lastModified: Long

  /** returns an input stream so the file can be read */
  def input: InputStream

  /** size of this file if it is a concrete file. */
  def size: Option[Int] = None

  /** returns contents of file (if applicable) in a byte array.
   *  warning: use <code>Global.getSourceFile()</code> to use the proper
   *  encoding when converting to the char array .
   *
   *  @throws java.io.IOException
   */
  final def toCharArray = new String(toByteArray).toCharArray

  /** returns contents of file (if applicable) in a byte array.
   *
   *  @throws java.io.IOException
   */
  @throws(classOf[IOException])
  final def toByteArray: Array[Byte] = {
    val in = input
    var rest = size.get
    val arr = new Array[Byte](rest)
    while (rest > 0) {
      val res = in.read(arr, arr.length - rest, rest)
      if (res == -1)
        throw new IOException("read error")
      rest -= res
    }
    in.close()
    arr
  }

  /** Returns all abstract subfiles of this abstract directory. */
  def elements: Iterator[AbstractFile]

  /** Returns the abstract file in this abstract directory with the specified
   *  name. If there is no such file, returns <code>null</code>. The argument
   *  <code>directory</code> tells whether to look for a directory or
   *  a regular file.
   *
   *  @param name      ...
   *  @param directory ...
   *  @return          ...
   */
  def lookupName(name: String, directory: Boolean): AbstractFile

  /** Returns the abstract file in this abstract directory with the specified
   *  path relative to it, If there is no such file, returns null. The argument
   *  <code>directory</code> tells whether to look for a directory or a regular
   *  file.
   *
   *  @param path      ...
   *  @param directory ...
   *  @return          ...
   */
  def lookupPath(path: String, directory: Boolean): AbstractFile = {
    val length = path.length()
    val separator = File.separatorChar
    assert(0 < length && path.lastIndexOf(separator) < length - 1, path)
    var file = this
    var start = 0
    while (true) {
      val index = path.indexOf(separator, start)
      assert(index < 0 || start < index)
      val name = path.substring(start, if (index < 0) length else index)
      file = file.lookupName(name, if (index < 0) directory else true)
      if ((file eq null) || index < 0) return file
      start = index + 1
    }
    file
  }

  /** Returns the path of this abstract file. */
  override def toString() = path

}