/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* 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 "nsIRequest.idl"

interface nsISimpleEnumerator;
interface nsIRequestObserver;
interface nsIInterfaceRequestor;
interface nsISchedulingContext;

typedef unsigned long nsLoadFlags;

/**
 * A load group maintains a collection of nsIRequest objects.
 * This is used in lots of places where groups of requests need to be tracked.
 * For example, nsIDocument::mDocumentLoadGroup is used to track all requests
 * made for subdocuments in order to track page load progress and allow all
 * requests made on behalf of the document to be stopped, etc.
 */
[scriptable, uuid(f0c87725-7a35-463c-9ceb-2c07f23406cc)]
interface nsILoadGroup : nsIRequest
{
    /**
     * The group observer is notified when requests are added to and removed
     * from this load group.  The groupObserver is weak referenced.
     */
    attribute nsIRequestObserver groupObserver;

    /**
     * Accesses the default load request for the group.  Each time a number
     * of requests are added to a group, the defaultLoadRequest may be set
     * to indicate that all of the requests are related to a base request.
     *
     * The load group inherits its load flags from the default load request.
     * If the default load request is NULL, then the group's load flags are
     * not changed.
     */
    attribute nsIRequest defaultLoadRequest;

    /**
     * Adds a new request to the group.  This will cause the default load
     * flags to be applied to the request.  If this is a foreground
     * request then the groupObserver's onStartRequest will be called.
     *
     * If the request is the default load request or if the default load
     * request is null, then the load group will inherit its load flags from
     * the request.
     */
    void addRequest(in nsIRequest aRequest,
                    in nsISupports aContext);

    /**
     * Removes a request from the group.  If this is a foreground request
     * then the groupObserver's onStopRequest will be called.
     *
     * By the time this call ends, aRequest will have been removed from the
     * loadgroup, even if this function throws an exception.
     */
    void removeRequest(in nsIRequest aRequest, 
                       in nsISupports aContext,
                       in nsresult aStatus);

    /**
     * Returns the requests contained directly in this group.
     * Enumerator element type: nsIRequest.
     */
    readonly attribute nsISimpleEnumerator requests;

    /**
     * Returns the count of "active" requests (ie. requests without the
     * LOAD_BACKGROUND bit set).
     */
    readonly attribute unsigned long activeCount;

    /**
     * Notification callbacks for the load group.
     */
    attribute nsIInterfaceRequestor notificationCallbacks;

    /**
     * Context for managing things like js/css connection blocking,
     * and per-tab connection grouping.
     */
    [noscript] readonly attribute nsID schedulingContextID;

    /**
     * The set of load flags that will be added to all new requests added to
     * this group. Any existing requests in the load group are not modified,
     * so it is expected these flags will be added before requests are added
     * to the group - typically via nsIDocShell::defaultLoadFlags on a new
     * docShell.
     * Note that these flags are *not* added to the default request for the
     * load group; it is expected the default request will already have these
     * flags (again, courtesy of setting nsIDocShell::defaultLoadFlags before
     * the docShell has created the default request.)
     */
    attribute nsLoadFlags defaultLoadFlags;
};