michael@0: /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #include "nsISupports.idl"
michael@0: 
michael@0: interface nsISimpleEnumerator;
michael@0: 
michael@0: /**
michael@0:  * nsIArray
michael@0:  *
michael@0:  * An indexed collection of elements. Provides basic functionality for
michael@0:  * retrieving elements at a specific position, searching for
michael@0:  * elements. Indexes are zero-based, such that the last element in the
michael@0:  * array is stored at the index length-1.
michael@0:  *
michael@0:  * For an array which can be modified, see nsIMutableArray below.
michael@0:  *
michael@0:  * Neither interface makes any attempt to protect the individual
michael@0:  * elements from modification. The convention is that the elements of
michael@0:  * the array should not be modified. Documentation within a specific
michael@0:  * interface should describe variations from this convention.
michael@0:  *
michael@0:  * It is also convention that if an interface provides access to an
michael@0:  * nsIArray, that the array should not be QueryInterfaced to an
michael@0:  * nsIMutableArray for modification. If the interface in question had
michael@0:  * intended the array to be modified, it would have returned an
michael@0:  * nsIMutableArray!
michael@0:  *
michael@0:  * null is a valid entry in the array, and as such any nsISupports
michael@0:  * parameters may be null, except where noted.
michael@0:  */
michael@0: [scriptable, uuid(114744d9-c369-456e-b55a-52fe52880d2d)]
michael@0: interface nsIArray : nsISupports
michael@0: {
michael@0:     /**
michael@0:      * length
michael@0:      *
michael@0:      * number of elements in the array.
michael@0:      */
michael@0:     readonly attribute unsigned long length;
michael@0: 
michael@0:     /**
michael@0:      * queryElementAt()
michael@0:      *
michael@0:      * Retrieve a specific element of the array, and QueryInterface it
michael@0:      * to the specified interface. null is a valid result for
michael@0:      * this method, but exceptions are thrown in other circumstances
michael@0:      * 
michael@0:      * @param index position of element
michael@0:      * @param uuid the IID of the requested interface
michael@0:      * @param result the object, QI'd to the requested interface
michael@0:      *
michael@0:      * @throws NS_ERROR_NO_INTERFACE when an entry exists at the
michael@0:      *         specified index, but the requested interface is not
michael@0:      *         available.
michael@0:      * @throws NS_ERROR_ILLEGAL_VALUE when index > length-1
michael@0:      *
michael@0:      */
michael@0:     void queryElementAt(in unsigned long index,
michael@0:                         in nsIIDRef uuid,
michael@0:                         [iid_is(uuid), retval] out nsQIResult result);
michael@0:     
michael@0:     /**
michael@0:      * indexOf()
michael@0:      * 
michael@0:      * Get the position of a specific element. Note that since null is
michael@0:      * a valid input, exceptions are used to indicate that an element
michael@0:      * is not found.
michael@0:      * 
michael@0:      * @param startIndex The initial element to search in the array
michael@0:      *                   To start at the beginning, use 0 as the
michael@0:      *                   startIndex
michael@0:      * @param element    The element you are looking for
michael@0:      * @returns a number >= startIndex which is the position of the
michael@0:      *          element in the array.
michael@0:      * @throws NS_ERROR_FAILURE if the element was not in the array.
michael@0:      */
michael@0:     unsigned long indexOf(in unsigned long startIndex,
michael@0:                           in nsISupports element);
michael@0: 
michael@0:     /**
michael@0:      * enumerate the array
michael@0:      *
michael@0:      * @returns a new enumerator positioned at the start of the array
michael@0:      * @throws NS_ERROR_FAILURE if the array is empty (to make it easy
michael@0:      *         to detect errors), or NS_ERROR_OUT_OF_MEMORY if out of memory.
michael@0:      */
michael@0:     nsISimpleEnumerator enumerate();
michael@0: };