// Connection.java - Implementation of URLConnection for core protocol.

/* Copyright (C) 2001, 2003  Free Software Foundation

   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 gnu.java.net.protocol.core;

import gnu.gcj.Core;
import java.io.InputStream;
import java.io.IOException;
import java.net.ProtocolException;
import java.net.URL;
import java.net.URLConnection;
import java.util.Map;
import java.util.Vector;
import java.util.Hashtable;
import java.util.Enumeration;

/**
 * @author Anthony Green <green@redhat.com>
 * @date August 13, 2001
 */

class Connection extends URLConnection
{
  private Hashtable hdrHash = new Hashtable();
  private Vector hdrVec = new Vector();
  private boolean gotHeaders = false;

  private Core core;

  public Connection (URL url)
  {
    super(url);
  }

  // Implementation of abstract method.
  public void connect() throws IOException
  {
    // Call is ignored if already connected.
    if (connected)
      return;

    // If not connected, then file needs to be opened.
    core = Core.create (url.getFile());
    connected = true;
  }

  public InputStream getInputStream() throws IOException
  {
    if (!connected)
      connect();

    if (! doInput)
      throw new ProtocolException("Can't open InputStream if doInput is false");
    return new CoreInputStream (core);
  }

  // Override default method in URLConnection.
  public String getHeaderField(String name)
  {
    try
      {
	getHeaders();
      }
    catch (IOException x)
      {
	return null;
      }
    return (String) hdrHash.get(name.toLowerCase());
  }

  // Override default method in URLConnection.
  public Map getHeaderFields()
  {
    try
      {
	getHeaders();
      }
    catch (IOException x)
      {
	return null;
      }
    return hdrHash;
  }

  // Override default method in URLConnection.
  public String getHeaderField(int n)
  {
    try
      {
	getHeaders();
      }
    catch (IOException x)
      {
	return null;
      }
    if (n < hdrVec.size())
      return getField ((String) hdrVec.elementAt(n));

    return null;
  }

  // Override default method in URLConnection.
  public String getHeaderFieldKey(int n)
  {
    try
      {
	getHeaders();
      }
    catch (IOException x)
      {
	return null;
      }
    if (n < hdrVec.size())
      return getKey ((String) hdrVec.elementAt(n));

    return null;
  }

  private String getKey(String str)
  {
    if (str == null)
      return null;
    int index = str.indexOf(':');
    if (index >= 0)
      return str.substring(0, index);
    else
      return null;
  }

  private String getField(String str)
  {
    if (str == null)
      return null;
    int index = str.indexOf(':');
    if (index >= 0)
      return str.substring(index + 1).trim();
    else
      return str;
  }

  private void getHeaders() throws IOException
  {
    if (gotHeaders)
      return;
    gotHeaders = true;

    connect();

    // Yes, it is overkill to use the hash table and vector here since
    // we're only putting one header in the file, but in case we need
    // to add others later and for consistency, we'll implement it this way.

    // Add the only header we know about right now:  Content-length.
    long len = core.length;
    String line = "Content-length: " + len;
    hdrVec.addElement(line);

    // The key will never be null in this scenario since we build up the
    // headers ourselves.  If we ever rely on getting a header from somewhere
    // else, then we may have to check if the result of getKey() is null.
    String key = getKey(line);
    hdrHash.put(key.toLowerCase(), Long.toString(len));
  }
}