/* -*- Mode: IDL; tab-width: 4; 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 nsIDOMEvent;
interface nsIDOMNode;

/**
 * An optional interface for embedding clients wishing to receive
 * notifications for context menu events (e.g. generated by
 * a user right-mouse clicking on a link). The embedder implements
 * this interface on the web browser chrome object associated
 * with the window that notifications are required for. When a context
 * menu event, the browser will call this interface if present.
 * 
 * @see nsIDOMNode
 * @see nsIDOMEvent
 */
[scriptable, uuid(3478b6b0-3875-11d4-94ef-0020183bf181)]
interface nsIContextMenuListener : nsISupports
{
    /** Flag. No context. */
    const unsigned long CONTEXT_NONE     = 0;
    /** Flag. Context is a link element. */
    const unsigned long CONTEXT_LINK     = 1;
    /** Flag. Context is an image element. */
    const unsigned long CONTEXT_IMAGE    = 2;
    /** Flag. Context is the whole document. */
    const unsigned long CONTEXT_DOCUMENT = 4;
    /** Flag. Context is a text area element. */
    const unsigned long CONTEXT_TEXT     = 8;
    /** Flag. Context is an input element. */
    const unsigned long CONTEXT_INPUT    = 16;

    /**
     * Called when the browser receives a context menu event (e.g. user is right-mouse
     * clicking somewhere on the document). The combination of flags, event and node
     * provided in the call indicate where and what was clicked on.
     *
     * The following table describes what context flags and node combinations are
     * possible.
     *
     * <TABLE>
     * <TR><TD><B>aContextFlag</B></TD><TD>aNode</TD></TR>
     * <TR><TD>CONTEXT_LINK</TD><TD>&lt;A&gt;</TD></TR>
     * <TR><TD>CONTEXT_IMAGE</TD><TD>&lt;IMG&gt;</TD></TR>
     * <TR><TD>CONTEXT_IMAGE | CONTEXT_LINK</TD><TD>&lt;IMG&gt;
     *       with an &lt;A&gt; as an ancestor</TD></TR>
     * <TR><TD>CONTEXT_INPUT</TD><TD>&lt;INPUT&gt;</TD></TR>
     * <TR><TD>CONTEXT_TEXT</TD><TD>&lt;TEXTAREA&gt;</TD></TR>
     * <TR><TD>CONTEXT_DOCUMENT</TD><TD>&lt;HTML&gt;</TD></TR>
     * </TABLE>
     *
     * @param aContextFlags Flags indicating the kind of context.
     * @param aEvent The DOM context menu event.
     * @param aNode The DOM node most relevant to the context.
     *
     * @return <CODE>NS_OK</CODE> always.
     */
    void onShowContextMenu(in unsigned long aContextFlags, in nsIDOMEvent aEvent, in nsIDOMNode aNode);
};