/* -*- 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 nsILoadGroupConnectionInfo;

/**
 * A load group maintains a collection of nsIRequest objects. 
 */
[scriptable, uuid(19501006-46e3-4634-b97d-26eff894b4d3)]
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;

    /**
     * Connection information for managing things like js/css
     * connection blocking, and per-tab connection grouping
     */
    readonly attribute nsILoadGroupConnectionInfo connectionInfo;
};

/**
 * Used to maintain state about the connections of a load group and
 * how they interact with blocking items like HEAD css/js loads.
 */
[uuid(d1f9f18e-3d85-473a-ad58-a2367d7cdb2a)]
interface nsILoadGroupConnectionInfo : nsISupports
{
    /**
     * Number of active blocking transactions associated with this load group
     */
    readonly attribute unsigned long blockingTransactionCount;

    /**
     * Increase the number of active blocking transactions associated
     * with this load group by one.
     */
    void addBlockingTransaction();

    /**
     * Decrease the number of active blocking transactions associated
     * with this load group by one. The return value is the number of remaining
     * blockers.
     */
    unsigned long removeBlockingTransaction();
};
