=pod

=head1 NAME

BIO_get_buffer_num_lines,
BIO_set_read_buffer_size,
BIO_set_write_buffer_size,
BIO_set_buffer_size,
BIO_set_buffer_read_data,
BIO_f_buffer
- buffering BIO

=head1 SYNOPSIS

 #include <openssl/bio.h>

 const BIO_METHOD *BIO_f_buffer(void);

 long BIO_get_buffer_num_lines(BIO *b);
 long BIO_set_read_buffer_size(BIO *b, long size);
 long BIO_set_write_buffer_size(BIO *b, long size);
 long BIO_set_buffer_size(BIO *b, long size);
 long BIO_set_buffer_read_data(BIO *b, void *buf, long num);

=head1 DESCRIPTION

BIO_f_buffer() returns the buffering BIO method.

Data written to a buffering BIO is buffered and periodically written
to the next BIO in the chain. Data read from a buffering BIO comes from
an internal buffer which is filled from the next BIO in the chain.
Both BIO_gets() and BIO_puts() are supported.

Calling BIO_reset() on a buffering BIO clears any buffered data.

BIO_get_buffer_num_lines() returns the number of lines currently buffered.

BIO_set_read_buffer_size(), BIO_set_write_buffer_size() and BIO_set_buffer_size()
set the read, write or both read and write buffer sizes to B<size>. The initial
buffer size is DEFAULT_BUFFER_SIZE, currently 4096. Any attempt to reduce the
buffer size below DEFAULT_BUFFER_SIZE is ignored. Any buffered data is cleared
when the buffer is resized.

BIO_set_buffer_read_data() clears the read buffer and fills it with B<num>
bytes of B<buf>. If B<num> is larger than the current buffer size the buffer
is expanded.

=head1 NOTES

These functions, other than BIO_f_buffer(), are implemented as macros.

Buffering BIOs implement BIO_read_ex() and BIO_gets() by using
BIO_read_ex() operations on the next BIO in the chain and storing the
result in an internal buffer, from which bytes are given back to the
caller as appropriate for the call; a BIO_gets() is guaranteed to give
the caller a whole line, and BIO_read_ex() is guaranteed to give the
caller the number of bytes it asks for, unless there's an error or end
of communication is reached in the next BIO.  By prepending a
buffering BIO to a chain it is therefore possible to provide
BIO_gets() or exact size BIO_read_ex() functionality if the following
BIOs do not support it.

Do not add more than one BIO_f_buffer() to a BIO chain.  The result of
doing so will force a full read of the size of the internal buffer of
the top BIO_f_buffer(), which is 4 KiB at a minimum.

Data is only written to the next BIO in the chain when the write buffer fills
or when BIO_flush() is called. It is therefore important to call BIO_flush()
whenever any pending data should be written such as when removing a buffering
BIO using BIO_pop(). BIO_flush() may need to be retried if the ultimate
source/sink BIO is non blocking.

=head1 RETURN VALUES

BIO_f_buffer() returns the buffering BIO method.

BIO_get_buffer_num_lines() returns the number of lines buffered (may be 0) or
a negative value in case of errors.

BIO_set_read_buffer_size(), BIO_set_write_buffer_size() and BIO_set_buffer_size()
return 1 if the buffer was successfully resized or <=0 for failure.

BIO_set_buffer_read_data() returns 1 if the data was set correctly or <=0 if
there was an error.

=head1 SEE ALSO

L<bio(7)>,
L<BIO_reset(3)>,
L<BIO_flush(3)>,
L<BIO_pop(3)>,
L<BIO_ctrl(3)>.

=head1 COPYRIGHT

Copyright 2000-2020 The OpenSSL Project Authors. All Rights Reserved.

Licensed under the Apache License 2.0 (the "License").  You may not use
this file except in compliance with the License.  You can obtain a cop/* AclEntry.java -- An entry in an ACL list.
   Copyright (C) 1998 Free Software Foundation, Inc.

This file is part of GNU Classpath.

GNU Classpath is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.

GNU Classpath is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
General Public License for more details.

You should have received a copy of the GNU General Public License
along with GNU Classpath; see the file COPYING.  If not, write to the
Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA.

Linking this library statically or dynamically with other modules is
making a combined work based on this library.  Thus, the terms and
conditions of the GNU General Public License cover the whole
combination.

As a special exception, the copyright holders of this library give you
permission to link this library with independent modules to produce an
executable, regardless of the license terms of these independent
modules, and to copy and distribute the resulting executable under
terms of your choice, provided that you also meet, for each linked
independent module, the terms and conditions of the license of that
module.  An independent module is a module which is not derived from
or based on this library.  If you modify this library, you may extend
this exception to your version of the library, but you are not
obligated to do so.  If you do not wish to do so, delete this
exception statement from your version. */

package java.security.acl;

import java.security.Principal;
import java.util.Enumeration;

/**
 * This interface models an entry in an access control list (ACL).  Java
 * ACL's consist of a list of entries, where each consists of a 
 * <code>Principal</code> and a list of <code>Permission</code>'s which
 * have been granted to that <code>Principal</code>.  An ACL can also
 * be <em>negative</em>, which indicates that the list of 
 * <code>Permission</code>'s is a list of permissions that are <em>not</em>
 * granted to the <code>Principal</code>.  A <code>Principal</code> can
 * have at most one regular (or positive) ACL entry and one negative
 * ACL entry.
 *
 * @version 0.0
 *
 * @author Aaron M. Renn (arenn@urbanophile.com)
 */
public interface AclEntry extends Cloneable
{
 /**
   * This method returns the <code>Principal</code> associated with this
   * ACL entry.
   *
   * @return The <code>Principal</code> for this ACL entry
   */
  Principal getPrincipal();

  /**
   * This method sets ths <code>Principal</code> associated with this
   * ACL entry.  This operation will only succeed if there is not already
   * a <code>Principal</code> assigned.
   *
   * @param user The <code>Principal</code> for this ACL entry
   *
   * @return <code>true</code> if the <code>Principal</code> was successfully set or <code>false</code> if this entry already has a <code>Principal</code>.
   */
  boolean setPrincipal(Principal user);

  /**
   * This method sets this ACL entry to be a <em>negative</em> entry, indicating
   * that it contains a list of permissions that are <em>not</em> granted
   * to the entry's <code>Principal</code>.  Note that there is no way to
   * undo this operation.
   */
  void setNegativePermissions();

  /**
   * This method tests whether or not this ACL entry is a negative entry or not.
   *
   * @return <code>true</code> if this ACL entry is negative, <code>false</code> otherwise
   */
  boolean isNegative();

  /**
   * This method adds the specified permission to this ACL entry.
   *
   * @param permission The <code>Permission</code> to add
   *
   * @return <code>true</code> if the permission was added or <code>false</code> if it was already set for this entry
   */
  boolean addPermission(Permission permission);

  /**
   * This method deletes the specified permission to this ACL entry.
   *
   * @param perm The <code>Permission</code> to delete from this ACL entry.
   *
   * @return <code>true</code> if the permission was successfully deleted or <code>false</code> if the permission was not part of this ACL to begin with
   */
  boolean removePermission(Permission perm);

  /**
   * This method tests whether or not the specified permission is associated
   * with this ACL entry.
   *
   * @param permission The <code>Permission</code> to test
   *
   * @return <code>true</code> if this permission is associated with this entry or <code>false</code> otherwise
   */
  boolean checkPermission(Permission permission);

  /**
   * This method returns a list of all <code>Permission</code> objects
   * associated with this ACL entry as an <code>Enumeration</code>.
   *
   * @return A list of permissions for this ACL entry
   */
  Enumeration<Permission> permissions();

  /**
   * This method returns this object as a <code>String</code>.
   *
   * @return A <code>String</code> representation of this object
   */
  String toString();

  /**
   * This method returns a clone of this ACL entry
   *
   * @return A clone of this ACL entry
   */
  Object clone();
}