/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 *
 * The contents of this file are subject to the Netscape Public
 * License Version 1.1 (the "License"); you may not use this file
 * except in compliance with the License. You may obtain a copy of
 * the License at http://www.mozilla.org/NPL/
 *
 * Software distributed under the License is distributed on an "AS
 * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
 * implied. See the License for the specific language governing
 * rights and limitations under the License.
 *
 * The Original Code is mozilla.org code.
 *
 * The Initial Developer of the Original Code is Netscape
 * Communications Corporation.  Portions created by Netscape are
 * Copyright (C) 1998 Netscape Communications Corporation. All
 * Rights Reserved.
 *
 * Contributor(s): 
 */

#include "nsISupports.idl"

interface nsILoadGroup;

typedef unsigned long nsLoadFlags;

/**
 * nsIRequest
 *
 * @status UNDER_REVIEW
 */
[scriptable, uuid(F2CAABA0-2F25-11d3-A164-0050041CAF44)]
interface nsIRequest : nsISupports
{
    /**
     * Returns the name of the request.  Often this is the URL of the request.
     */
    readonly attribute wstring name;

    /**
     * Returns true if the request is pending (active).  Returns false 
     * after completion or successful calling Cancel.  Suspended requests
     * are still considered pending.
     */
    boolean isPending();

    /**
     * Returns any error status associated with the request.
     */
    readonly attribute nsresult status;

    /**
     * Cancels the current request.  This will close any open input or
     * output streams and terminate any async requests.  Users should 
     * normally pass NS_BINDING_ABORTED, although other errors may also
     * be passed.  The error passed in will become the value of the 
     * status attribute.
     */
    void cancel(in nsresult status);

    /**
     * Suspends the current requests.  This may have the effect of closing
     * any underlying transport (in order to free up resources), although
     * any open streams remain logically opened and will continue delivering
     * data when the transport is resumed. 
     */
    void suspend();

    /**
     * Resumes the current request.  This may have the effect of re-opening
     * any underlying transport and will resume the delivery of data to 
     * any open streams. 
     */
    void resume();

    /**
     * Accesses the load group in which this request is currently a member.
     */
    attribute nsILoadGroup loadGroup;

    /**
     * Accesses the load flags for this request.  Bits 0-15 are defined (or
     * reserved) by nsIRequest.  When added to a load group, this request's
     * load flags are merged with the load flags of the load group.
     */
    attribute nsLoadFlags loadFlags;

    /**************************************************************************
     * Listed below are the various load flags which may be or'd together.
     */

    /**
     * No special load flags:
     */
    const unsigned long LOAD_NORMAL = 0;

    /** 
     * Don't deliver status notifications to the nsIProgressEventSink, or keep 
     * this load from completing the nsILoadGroup it may belong to.
     */
    const unsigned long LOAD_BACKGROUND = 1 << 0; 

    /**************************************************************************
     * The following flags control the flow of data into the cache.
     */

    /**
     * This flag prevents caching of any kind.  It does not, however, prevent
     * cached content from being used to satisfy this request.
     */
    const unsigned long INHIBIT_CACHING = 1 << 7;

    /**
     * This flag prevents caching on disk (or other persistent media), which
     * may be needed to preserve privacy.  For HTTPS, this flag is set auto-
     * matically.
     */
    const unsigned long INHIBIT_PERSISTENT_CACHING = 1 << 8;

    /**************************************************************************
     * The following flags control what happens when the cache contains data
     * that could perhaps satisfy this request.  They are listed in descending
     * order of precidence.
     */

    /**
     * Force an end-to-end download of content data from the origin server.
     * This flag is used for a shift-reload.
     */
    const unsigned long LOAD_BYPASS_CACHE = 1 << 9;

    /**
     * Load from the cache, bypassing protocol specific validation logic.  This
     * flag is used when browsing via history.  It is not recommended for normal
     * browsing as it may likely violate reasonable assumptions made by the 
     * server and confuse users.
     */
    const unsigned long LOAD_FROM_CACHE   = 1 << 10;

    /**
     * The following flags control the frequency of cached content validation
     * when neither LOAD_BYPASS_CACHE or LOAD_FROM_CACHE are set.  By default,
     * cached content is automatically validated if necessary before reuse.
     * 
     * VALIDATE_ALWAYS forces validation of any cached content independent of
     * its expiration time.
     * 
     * VALIDATE_NEVER disables validation of expired content.
     *
     * VALIDATE_ONCE_PER_SESSION disables validation of expired content, 
     * provided it has already been validated (at least once) since the start 
     * of this session.
     *
     * NOTE TO IMPLEMENTORS:
     *   These flags are intended for normal browsing, and they should therefore
     *   not apply to content that must be validated before each use.  Consider,
     *   for example, a HTTP response with a "Cache-control: no-cache" header.
     *   According to RFC2616, this response must be validated before it can
     *   be taken from a cache.  Breaking this requirement could result in 
     *   incorrect and potentially unpleasant side-effects.
     */
    const unsigned long VALIDATE_ALWAYS           = 1 << 11;
    const unsigned long VALIDATE_NEVER            = 1 << 12;
    const unsigned long VALIDATE_ONCE_PER_SESSION = 1 << 13;
};
