gecko-dev/xpcom/components/nsIClassInfo.idl

/* -*- Mode: C++; tab-width: 8; 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 "nsISupports.idl"

interface nsIXPCScriptable;

/**
 * Provides information about a specific implementation class.  If you want
 * your class to implement nsIClassInfo, see nsIClassInfoImpl.h for
 * instructions--you most likely do not want to inherit from nsIClassInfo.
 */

[scriptable, uuid(a60569d7-d401-4677-ba63-2aa5971af25d)]
interface nsIClassInfo : nsISupports
{
    /**
     * Get an ordered list of the interface ids that instances of the class 
     * promise to implement. Note that nsISupports is an implicit member 
     * of any such list and need not be included. 
     *
     * Should set *count = 0 and *array = null and return NS_OK if getting the 
     * list is not supported.
     */
    void getInterfaces(out uint32_t count, 
                       [array, size_is(count), retval] out nsIIDPtr array);

    /**
     * Return an object to assist XPConnect in supplying JavaScript-specific
     * behavior to callers of the instance object, or null if not needed.
     */
    nsIXPCScriptable getScriptableHelper();

    /**
     * A contract ID through which an instance of this class can be created
     * (or accessed as a service, if |flags & SINGLETON|), or null/void.
     */
    readonly attribute AUTF8String contractID;

    /**
     * A human readable string naming the class, or null/void.
     */
    readonly attribute AUTF8String classDescription;

    /**
     * A class ID through which an instance of this class can be created
     * (or accessed as a service, if |flags & SINGLETON|), or null.
     */
    readonly attribute nsCIDPtr classID;

    /**
     * Bitflags for 'flags' attribute.
     */
    const uint32_t SINGLETON            = 1 << 0;
    const uint32_t THREADSAFE           = 1 << 1;
    const uint32_t MAIN_THREAD_ONLY     = 1 << 2;
    const uint32_t DOM_OBJECT           = 1 << 3;
    const uint32_t PLUGIN_OBJECT        = 1 << 4;
    const uint32_t SINGLETON_CLASSINFO  = 1 << 5;

    /**
     * 'flags' attribute bitflag: whether objects of this type implement
     * nsIContent.
     */
    const uint32_t CONTENT_NODE         = 1 << 6;

    // The high order bit is RESERVED for consumers of these flags. 
    // No implementor of this interface should ever return flags 
    // with this bit set.
    const uint32_t RESERVED             = 1 << 31;


    readonly attribute uint32_t flags;

    /**
     * Also a class ID through which an instance of this class can be created
     * (or accessed as a service, if |flags & SINGLETON|).  If the class does
     * not have a CID, it should return NS_ERROR_NOT_AVAILABLE.  This attribute
     * exists so C++ callers can avoid allocating and freeing a CID, as would
     * happen if they used classID.
     */
    [noscript] readonly attribute nsCID classIDNoAlloc;

};