/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 * 
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "nsISupports.idl"

interface nsILDAPBERValue;


/**
 * nsILDAPBERElement is a wrapper interface for a C-SDK BerElement object.
 * Typically, this is used as an intermediate object to aid in the manual 
 * construction of a BER value.  Once the construction is completed by calling
 * methods on this object, an nsILDAPBERValue can be retrieved from the 
 * asValue attribute on this interface.
 *
 * <http://www.mozilla.org/directory/ietf-docs/draft-ietf-ldapext-ldap-c-api-05.txt>
 * contains some documentation that mostly (but not exactly) matches
 * the code that this wraps in section 17.
 */

[scriptable, uuid(409f5b31-c062-4d11-a35b-0a09e7967bf2)]
interface nsILDAPBERElement : nsISupports 
{
  /**
   * Initialize this object.  Must be called before calling any other method
   * on this interface.
   *
   * @param  aValue  value to preinitialize with; 0 for a new empty object
   *
   * @exception  NS_ERROR_NOT_IMPLEMENTED  preinitialization is currently
   *                                       not implemented
   * @exception  NS_ERROR_OUT_OF_MEMORY    unable to allocate the internal
   *                                       BerElement
   */
  void init(in nsILDAPBERValue aValue);

  /**
   * Most TAG_* constants can be used in the construction or passing in of 
   * values to the aTag arguments to most of the methods in this interface.
   */

  /** 
   * When returned from a parsing method, 0xffffffff is referred to 
   * has the parse-error semantic (ie TAG_LBER_ERROR); when passing it to
   * a construction method, it is used to mean "pick the default tag for 
   * this type" (ie TAG_LBER_DEFAULT).
   */
  const unsigned long TAG_LBER_ERROR = 0xffffffff;
  const unsigned long TAG_LBER_DEFAULT = 0xffffffff;
  const unsigned long TAG_LBER_END_OF_SEQORSET = 0xfffffffe;

  /** 
   * BER encoding types and masks
   */
  const unsigned long TAG_LBER_PRIMITIVE = 0x00;

  /**
   * The following two tags are carried over from the LDAP C SDK; their
   * exact purpose there is not well documented.  They both have
   * the same value there as well.
   */
  const unsigned long TAG_LBER_CONSTRUCTED = 0x20;
  const unsigned long TAG_LBER_ENCODING_MASK = 0x20;

  const unsigned long TAG_LBER_BIG_TAG_MASK = 0x1f;
  const unsigned long TAG_LBER_MORE_TAG_MASK = 0x80;

  /**
   * general BER types we know about
   */
  const unsigned long TAG_LBER_BOOLEAN = 0x01;
  const unsigned long TAG_LBER_INTEGER = 0x02;
  const unsigned long TAG_LBER_BITSTRING = 0x03;
  const unsigned long TAG_LBER_OCTETSTRING = 0x04;
  const unsigned long TAG_LBER_NULL =	0x05;
  const unsigned long TAG_LBER_ENUMERATED = 0x0a;
  const unsigned long TAG_LBER_SEQUENCE	= 0x30;
  const unsigned long TAG_LBER_SET = 0x31;

  /**
   * Write a string to this element.  
   *
   * @param  aString  string to write
   * @param  aTag     tag for this string (if TAG_LBER_DEFAULT is used,
   *                  TAG_LBER_OCTETSTRING will be written).
   *
   * @return     number of bytes written
   *
   * @exception  NS_ERROR_FAILUE   C-SDK returned error
   */
  unsigned long putString(in AUTF8String aString, in unsigned long aTag);

  /**
   * Start a set.  Sets may be nested.
   *
   * @param  aTag  tag for this set (if TAG_LBER_DEFAULT is used, 
   *               TAG_LBER_SET will be written).
   *
   * @exception  NS_ERROR_FAILUE   C-SDK returned an error
   */
  void startSet(in unsigned long aTag);

  /**
   * Cause the entire set started by the last startSet() call to be written.
   *
   * @exception  NS_ERROR_FAILUE   C-SDK returned an error
   *
   * @return     number of bytes written
   */
  unsigned long putSet();

  /**
   * an nsILDAPBERValue version of this element.  Calls ber_flatten() under
   * the hood.
   *
   * @exception NS_ERROR_OUT_OF_MEMORY
   */
  readonly attribute nsILDAPBERValue asValue;
};