gcc/libjava/java/util/Properties.java

// Properties - Property list representation.

/* Copyright (C) 1998, 1999  Cygnus Solutions

   This file is part of libgcj.

This software is copyrighted work licensed under the terms of the
Libgcj License.  Please consult the file "LIBGCJ_LICENSE" for
details.  */

package java.util;

import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.PrintStream;
import java.io.PrintWriter;
import java.io.PushbackReader;

/**
 * @author Tom Tromey <tromey@cygnus.com>
 * @date October 26, 1998.
 */

/* Written using "Java Class Libraries", 2nd edition, ISBN 0-201-31002-3
 * Status: Complete to JDK 1.1.
 */

public class Properties extends Hashtable
{
  protected Properties defaults;

  public String getProperty (String propName)
    {
      return getProperty (propName, null);
    }

  public String getProperty (String propName, String defVal)
    {
      String r = (String) get (propName);
      if (r == null)
	{
	  if (defaults != null)
	    r = defaults.getProperty(propName, defVal);
	  else
	    r = defVal;
	}
      return r;
    }

  public void list (PrintStream out)
    {
      Enumeration e = propertyNames ();
      while (e.hasMoreElements())
	{
	  String key = (String) e.nextElement();
	  String value = getProperty(key);
	  if (value != null)
	    {
	      if (value.length() > 40)
		{
		  // JDK compatibility.
		  value = value.substring(0, 37) + "...";
		}
	      out.print(key);
	      out.print("=");
	      out.println(value);
	    }
	}
    }

  public void list (PrintWriter writer)
    {
      Enumeration e = propertyNames ();
      while (e.hasMoreElements())
	{
	  String key = (String) e.nextElement();
	  String value = getProperty(key);
	  if (value != null)
	    {
	      if (value.length() > 40)
		{
		  // JDK compatibility.
		  value = value.substring(0, 37) + "...";
		}
	      writer.print(key);
	      writer.print("=");
	      writer.println(value);
	    }
	}
    }

  private final boolean skip_ws (PushbackReader reader) throws IOException
    {
      while (true)
	{
	  int c = reader.read();
	  if (c == -1)
	    return false;
	  // FIXME: we use our own definition of whitespace.
	  // Character.isWhitespace includes newlines, which we don't
	  // want.  Character.isSpaceChar doesn't include \t.
	  if (c != ' ' && c != '\t')
	    {
	      reader.unread(c);
	      return true;
	    }
	}
    }

  // Note: this method needs to be rewritten for JDK 1.2.
  // We rather arbitrarily decide that an EOF in the middle of a line
  // means that the whole line should be ignored.  The spec doesn't
  // specifically address this, but this interpretation seems valid.
  public synchronized void load (InputStream in) throws IOException
    {
      PushbackReader reader = new PushbackReader (new InputStreamReader (in));

      StringBuffer key = new StringBuffer ();
      StringBuffer value = new StringBuffer ();

    nextLine:
      while (true)
	{
	  key.setLength(0);
	  value.setLength(0);

	  // Skip leading whitespace.
	  if (! skip_ws (reader))
	    return;

	  // Read key until key terminator.
	  boolean first_char = true;
	  int c;
	  while (true)
	    {
	      c = reader.read();
	      if (c == -1)
		return;
	      if (c == '\\')
		{
		  first_char = false;
		  c = reader.read();
		  if (c == -1)
		    return;
		}

	      // If we found a comment, just read to end of line and
	      // then keep going.
	      if (first_char == true && (c == '#' || c == '!'))
		{
		  while (c != -1 && c != '\r' && c != '\n')
		    c = reader.read();
		  if (c == -1)
		    return;
		  continue nextLine;
		}

	      if (c == '\r' || c == '\n')
		{
		  if (first_char)
		    continue nextLine;
		  reader.unread(c);
		  break;
		}
	      // FIXME: again, our own definition of whitespace.
	      if (c == ' ' || c == '\t' || c == ':' || c == '=')
		break;

	      first_char = false;
	      key.append((char) c);
	    }

	  // Found end of key.  Skip whitespace.  If the terminator
	  // was whitespace, also skip a single instance of a "real"
	  // terminator, and then more whitespace.
	  if (! skip_ws (reader))
	    return;
	  if (c != ':' && c != '=')
	    {
	      c = reader.read();
	      if (c == -1)
		return;
	      if (c == ':' || c == '=')
		{
		  // Skip more whitespace.
		  if (! skip_ws (reader))
		    return;
		}
	      else
		reader.unread(c);
	    }

	  // Now read the value.
	  while (true)
	    {
	      c = reader.read();
	      if (c == -1)
		return;
	      if (c == '\r' || c == '\n')
		break;
	      if (c == '\\')
		{
		  c = reader.read();
		  switch (c)
		    {
		    case -1:
		      return;
		    case 't':
		      c = '\t';
		      break;
		    case 'r':
		      c = '\r';
		      break;
		    case 'n':
		      c = '\n';
		      break;
		    case 'u':
		      c = 0;
		      for (int i = 0; i < 4; ++i)
			{
			  int x = reader.read();
			  if (x == -1)
			    return;
			  int d = Character.digit((char) x, 16);
			  // We follow JDK here: invalid characters
			  // are treated as terminators.
			  if (d == -1)
			    {
			      value.append((char) c);
			      c = x;
			      break;
			    }
			  c <<= 4;
			  c |= d;
			}
		      break;
		    default:
		      // Nothing.
		    }
		}
	      value.append((char) c);
	    }

	  put (key.toString(), value.toString());
	}
    }

  public Properties ()
    {
      defaults = null;
    }

  public Properties (Properties defs)
    {
      defaults = defs;
    }

  private final void addHashEntries (Hashtable base)
    {
      if (defaults != null)
	defaults.addHashEntries(base);
      Enumeration keys = keys ();
      while (keys.hasMoreElements())
	base.put(keys.nextElement(), base);
    }

  public Enumeration propertyNames ()
    {
      // We make a new Hashtable that holds all the keys.  Then we
      // return an enumeration for this hash.  We do this because we
      // don't want modifications to be reflected in the enumeration
      // (per JCL), and because there doesn't seem to be a
      // particularly better way to ensure that duplicates are
      // ignored.
      Hashtable t = new Hashtable ();
      addHashEntries (t);
      return t.keys();
    }

  public synchronized void save (OutputStream out, String comment)
    {
      // Use a buffer because writing a single string through
      // OutputStreamWriter is fairly expensive.
      BufferedWriter output
	= new BufferedWriter (new OutputStreamWriter (out));
      String newline = System.getProperty("line.separator");

      try
	{
	  if (comment != null)
	    {
	      // We just lose if COMMENT contains a newline.  This is
	      // what JDK 1.1 does.
	      output.write("#");
	      output.write(comment);
	      output.write(newline);
	    }
	  output.write("# ");
	  output.write(new Date().toString());
	  output.write(newline);

	  Enumeration keys = keys ();
	  while (keys.hasMoreElements())
	    {
	      String key = (String) keys.nextElement();
	      String value = (String) get (key);

	      // FIXME: JCL says that the key can contain many Unicode
	      // characters.  But it also doesn't say we should encode
	      // it in any way.
	      // FIXME: if key contains ':', '=', or whitespace, must
	      // quote it here.  Note that JDK 1.1 does not do this.
	      output.write(key);
	      output.write("=");

	      boolean leading = true;
	      for (int i = 0; i < value.length(); ++i)
		{
		  boolean new_lead = false;
		  char c = value.charAt(i);
		  switch (c)
		    {
		    case '\n':
		      output.write("\\n");
		      break;
		    case '\r':
		      output.write("\\r");
		      break;
		    case '\t':
		      output.write("\\t");
		      break;
		    case '\\':
		      output.write("\\\\");
		      break;

		    case '#':
		    case '!':
		    case '=':
		    case ':':
		      output.write("\\");
		      output.write(c);
		      break;

		    case ' ':
		      new_lead = leading;
		      if (leading)
			output.write("\\");
		      output.write(c);
		      break;

		    default:
		      if (c < '\u0020' || c > '\u007e')
			{
			  output.write("\\u");
			  output.write(Character.forDigit(c >>> 12, 16));
			  output.write(Character.forDigit((c >>> 8) & 0xff,
							  16));
			  output.write(Character.forDigit((c >>> 4) & 0xff,
							  16));
			  output.write(Character.forDigit(c & 0xff, 16));
			}
		      else
			output.write(c);
		    }
		  leading = new_lead;
		}
	      output.write(newline);
	    }

	  output.flush();
	}
      catch (IOException ignore)
	{
	}
    }
}