file.java

gcc的组建

      {
        // On Windows, a process has a current working directory for
        // each drive and a path like "G:foo\bar" would mean the 
        // absolute path "G:\wombat\foo\bar" if "\wombat" is the 
        // working directory on the G drive.
        String drvDir = null;
        try
          {
            drvDir = new File (path.substring (0, 2)).getCanonicalPath();
          }
        catch (IOException e)
          {
            drvDir = path.substring (0, 2) + "\\";
          }
        
        // Note: this would return "C:\\." for the path "C:.", if "\"
        // is the working folder on the C drive, but this is 
        // consistent with what Sun's JRE 1.4.1.01 actually returns!
        if (path.length() > 2)
          return drvDir + '\\' + path.substring (2, path.length());
        else
          return drvDir;
      }
    else
      return System.getProperty ("user.dir") + separatorChar + path;
  }

  /**
   * This method returns a <code>File</code> object representing the
   * absolute path of this object.
   *
   * @return A <code>File</code> with the absolute path of the object.
   *
   * @since 1.2
   */
  public File getAbsoluteFile()
  {
    return new File(getAbsolutePath());
  }

  /**
   * This method returns a canonical representation of the pathname of
   * this file.  The actual form of the canonical representation is
   * different.  On the GNU system, the canonical form differs from the
   * absolute form in that all relative file references to "." and ".."
   * are resolved and removed.
   * <p>
   * Note that this method, unlike the other methods which return path
   * names, can throw an IOException.  This is because native method 
   * might be required in order to resolve the canonical path
   *
   * @exception IOException If an error occurs
   */
  public native String getCanonicalPath() throws IOException;

  /**
   * This method returns a <code>File</code> object representing the
   * canonical path of this object.
   *
   * @return A <code>File</code> instance representing the canonical path of
   * this object.
   *
   * @exception IOException If an error occurs.
   *
   * @since 1.2
   */
  public File getCanonicalFile() throws IOException
  {
    return new File(getCanonicalPath());
  }

  /**
   * This method returns the name of the file.  This is everything in the
   * complete path of the file after the last instance of the separator
   * string.
   *
   * @return The file name
   */
  public String getName()
  {
    int nameSeqIndex = 0;

    if (separatorChar == '\\' && path.length() > 1)
      {
        // On Windows, ignore the drive specifier or the leading '\\'
        // of a UNC network path, if any (a.k.a. the "prefix").
        if ((path.charAt (0) == '\\' && path.charAt (1) == '\\')
            || (((path.charAt (0) >= 'a' && path.charAt (0) <= 'z')
		 || (path.charAt (0) >= 'A' && path.charAt (0) <= 'Z'))
		&& path.charAt (1) == ':'))
	  {
	    if (path.length() > 2)
	      nameSeqIndex = 2;
	    else
	      return "";
	  }
      }

    String nameSeq 
      = (nameSeqIndex > 0 ? path.substring (nameSeqIndex) : path);

    int last = nameSeq.lastIndexOf (separatorChar);

    return nameSeq.substring (last + 1);
  }

  /**
   * This method returns a <code>String</code> the represents this file's
   * parent.  <code>null</code> is returned if the file has no parent.  The
   * parent is determined via a simple operation which removes the
   *
   * @return The parent directory of this file
   */
  public String getParent()
  {
    String prefix = null;
    int nameSeqIndex = 0;

    // The "prefix", if present, is the leading "/" on UNIX and 
    // either the drive specifier (e.g. "C:") or the leading "\\"
    // of a UNC network path on Windows.
    if (separatorChar == '/' && path.charAt (0) == '/')
      {
        prefix = "/";
        nameSeqIndex = 1;
      }
    else if (separatorChar == '\\' && path.length() > 1)
      {
        if ((path.charAt (0) == '\\' && path.charAt (1) == '\\')
            || (((path.charAt (0) >= 'a' && path.charAt (0) <= 'z')
                 || (path.charAt (0) >= 'A' && path.charAt (0) <= 'Z'))
                && path.charAt (1) == ':'))
          {
            prefix = path.substring (0, 2);
            nameSeqIndex = 2;
          }
      }

    // According to the JDK docs, the returned parent path is the 
    // portion of the name sequence before the last separator
    // character, if found, prefixed by the prefix, otherwise null.
    if (nameSeqIndex < path.length())
      {
        String nameSeq = path.substring (nameSeqIndex, path.length());
        int last = nameSeq.lastIndexOf (separatorChar);
        if (last == -1)
          return prefix;
        else if (last == (nameSeq.length() - 1))
          // Note: The path would not have a trailing separator
          // except for cases like "C:\" on Windows (see 
          // normalizePath( )), where Sun's JRE 1.4 returns null.
          return null;
        else if (last == 0)
          last++;

        if (prefix != null)
          return prefix + nameSeq.substring (0, last);
        else
          return nameSeq.substring (0, last);
      }
    else
      // Sun's JRE 1.4 returns null if the prefix is the only 
      // component of the path - so "/" gives null on UNIX and 
      // "C:", "\\", etc. return null on Windows.
      return null;
  }

  /**
   * This method returns a <code>File</code> object representing the parent
   * file of this one.
   *
   * @return a <code>File</code> for the parent of this object.  
   * <code>null</code>
   * will be returned if this object does not have a parent.
   *
   * @since 1.2
   */
  public File getParentFile()
  {
    String parent = getParent();
    return parent != null ? new File(parent) : null;
  }

  /**
   * Returns the path name that represents this file.  May be a relative
   * or an absolute path name
   *
   * @return The pathname of this file
   */
  public String getPath()
  {
    return path;
  }

  /**
   * This method returns a hash code representing this file.  It is the
   * hash code of the path of this file (as returned by <code>getPath()</code>)
   * exclusived or-ed with the value 1234321.
   *
   * @return The hash code for this object
   */
  public int hashCode()
  {
    if (caseSensitive)
      return path.hashCode() ^ 1234321;
    else
      return path.toLowerCase().hashCode() ^ 1234321;
  }

  /**
   * This method returns true if this object represents an absolute file
   * path and false if it does not.  The definition of an absolute path varies
   * by system.  As an example, on GNU systems, a path is absolute if it starts
   * with a "/".
   *
   * @return <code>true</code> if this object represents an absolute 
   * file name, <code>false</code> otherwise.
   */
  public native boolean isAbsolute();

  /**
   * This method tests whether or not the file represented by this object
   * is a directory.  In order for this method to return <code>true</code>,
   * the file represented by this object must exist and be a directory.
   * 
   * @return <code>true</code> if this file is a directory, <code>false</code>
   * otherwise
   *
   * @exception SecurityException If reading of the file is not permitted
   */
  public boolean isDirectory()
  {
    checkRead();
    return _stat (DIRECTORY);
  }

  /**
   * This method tests whether or not the file represented by this object
   * is a "plain" file.  A file is a plain file if and only if it 1) Exists,
   * 2) Is not a directory or other type of special file.
   *
   * @return <code>true</code> if this is a plain file, <code>false</code> 
   * otherwise
   *
   * @exception SecurityException If reading of the file is not permitted
   */
  public boolean isFile()
  {
    checkRead();
    return _stat (ISFILE);
  }

  /**
   * This method tests whether or not this file represents a "hidden" file.
   * On GNU systems, a file is hidden if its name begins with a "."
   * character.  Files with these names are traditionally not shown with
   * directory listing tools.
   *
   * @return <code>true</code> if the file is hidden, <code>false</code>
   * otherwise.
   *
   * @since 1.2
   */
  public boolean isHidden()
  {
    checkRead();
    return _stat (ISHIDDEN);
  }

  /**
   * This method returns the last modification time of this file.  The
   * time value returned is an abstract value that should not be interpreted
   * as a specified time value.  It is only useful for comparing to other
   * such time values returned on the same system.  In that case, the larger
   * value indicates a more recent modification time. 
   * <p>
   * If the file does not exist, then a value of 0 is returned.
   *
   * @return The last modification time of the file
   *
   * @exception SecurityException If reading of the file is not permitted
   */
  public long lastModified()
  {
    checkRead();
    return attr (MODIFIED);
  }

  /**
   * This method returns the length of the file represented by this object,
   * or 0 if the specified file does not exist.
   *
   * @return The length of the file
   *
   * @exception SecurityException If reading of the file is not permitted
   */
  public long length()
  {
    checkRead();
    return attr (LENGTH);
  }

  /*
   * This native function actually produces the list of file in this
   * directory
   */
  private final native Object[] performList (FilenameFilter filter,
					     FileFilter fileFilter,
					     Class result_type);

  /**
   * This method returns a array of <code>String</code>'s representing the
   * list of files is then directory represented by this object.  If this
   * object represents a non-directory file or a non-existent file, then
   * <code>null</code> is returned.  The list of files will not contain
   * any names such as "." or ".." which indicate the current or parent
   * directory.  Also, the names are not guaranteed to be sorted.
   * <p>
   * In this form of the <code>list()</code> method, a filter is specified
   * that allows the caller to control which files are returned in the
   * list.  The <code>FilenameFilter</code> specified is called for each
   * file returned to determine whether or not that file should be included
   * in the list.
   * <p>
   * A <code>SecurityManager</code> check is made prior to reading the
   * directory.  If read access to the directory is denied, an exception
   * will be thrown.
   *
   * @param filter An object which will identify files to exclude from 
   * the directory listing.
   *
   * @return An array of files in the directory, or <code>null</code> 
   * if this object does not represent a valid directory.
   * 
   * @exception SecurityException If read access is not allowed to the 
   * directory by the <code>SecurityManager</code>
   */
  public String[] list(FilenameFilter filter)
  {
    checkRead();
    return (String[]) performList (filter, null, String.class);
  }

  /**
   * This method returns a array of <code>String</code>'s representing the
   * list of files is then directory represented by this object.  If this
   * object represents a non-directory file or a non-existent file, then
   * <code>null</code> is returned.  The list of files will not contain
   * any names such as "." or ".." which indicate the current or parent
   * directory.  Also, the names are not guaranteed to be sorted.
   * <p>
   * A <code>SecurityManager</code> check is made prior to reading the
   * directory.  If read access to the directory is denied, an exception
   * will be thrown.
   *
   * @return An array of files in the directory, or <code>null</code> if 
   * this object does not represent a valid directory.
   * 
   * @exception SecurityException If read access is not allowed to the 
   * directory by the <code>SecurityManager</code>
   */
  public String[] list()
  {
    checkRead();
    return (String[]) performList (null, null, String.class);
  }

  /**
   * This method returns an array of <code>File</code> objects representing
   * all the files in the directory represented by this object. If this
   * object does not represent a directory, <code>null</code> is returned.
   * Each of the returned <code>File</code> object is constructed with this
   * object as its parent.
   * <p>
   * A <code>SecurityManager</code> check is made prior to reading the
   * directory.  If read access to the directory is denied, an exception
   * will be thrown.
   *
   * @return An array of <code>File</code> objects for this directory.
   *
   * @exception SecurityException If the <code>SecurityManager</code> denies
   * access to this directory.
   *
   * @since 1.2
   */
  public File[] listFiles()
  {
    checkRead();
    return (File[]) performList (null, null, File.class);
  }
  
  /**
   * This method returns an array of <code>File</code> objects representing
   * all the files in the directory represented by this object. If this
   * object does not represent a directory, <code>null</code> is returned.
   * Each of the returned <code>File</code> object is constructed with this
   * object as its parent.
   * <p> 
   * In this form of the <code>listFiles()</code> method, a filter is specified
   * that allows the caller to control which files are returned in the
   * list.  The <code>FilenameFilter</code> specified is called for each
   * file returned to determine whether or not that file should be included
   * in the list.
   * <p>
   * A <code>SecurityManager</code> check is made prior to reading the
   * directory.  If read access to the directory is denied, an exception
   * will be thrown.
   *
   * @return An array of <code>File</code> objects for this directory.
   *
   * @exception SecurityException If the <code>SecurityManager</code> denies
   * access to this directory.
   *
   * @since 1.2
   */
  public File[] listFiles(FilenameFilter filter)
  {
    checkRead();
    return (File[]) performList (filter, null, File.class);
  }

  /**
   * This method returns an array of <code>File</code> objects representing
   * all the files in the directory represented by this object. If this
   * object does not represent a directory, <code>null</code> is returned.
   * Each of the returned <code>File</code> object is constructed with this
   * object as its parent.
   * <p> 
   * In this form of the <code>listFiles()</code> method, a filter is specified
   * that allows the caller to control which files are returned in the
   * list.  The <code>FileFilter</code> specified is called for each
   * file returned to determine whether or not that file should be included
   * in the list.
   * <p>
   * A <code>SecurityManager</code> check is made prior to reading the
   * directory.  If read access to the directory is denied, an exception
   * will be thrown.
   *
   * @return An array of <code>File</code> objects for this directory.
   *
   * @exception SecurityException If the <code>SecurityManager</code> denies
   * access to this directory.
   *
   * @since 1.2
   */
  public File[] listFiles(FileFilter filter)
  {
    checkRead();
    return (File[]) performList (null, filter, File.class);
  }

  /**
   * This method returns a <code>String</code> that is the path name of the
   * file as returned by <code>getPath</code>.
   *
   * @return A <code>String</code> representation of this file
   */
  public String toString()
  {
    return path;
  }

  /**
   * @return A <code>URI</code> for this object.
   */
  public URI toURI()
  {