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/* -*- Mode: C++; tab-width: 2; 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 "imgINotificationObserver.idl"
%{C++
#include "mozilla/Maybe.h"
#include "Visibility.h"
%}
interface imgIRequest;
interface nsIChannel;
interface nsIStreamListener;
interface nsIURI;
interface nsIFrame;
[ref] native MaybeOnNonvisible(const mozilla::Maybe<mozilla::OnNonvisible>);
native Visibility(mozilla::Visibility);
/**
* This interface represents a content node that loads images. The interface
* exists to allow getting information on the images that the content node
* loads and to allow registration of observers for the image loads.
*
* Implementors of this interface should handle all the mechanics of actually
* loading an image -- getting the URI, checking with content policies and
* the security manager to see whether loading the URI is allowed, performing
* the load, firing any DOM events as needed.
*
* An implementation of this interface may support the concepts of a
* "current" image and a "pending" image. If it does, a request to change
* the currently loaded image will start a "pending" request which will
* become current only when the image is loaded. It is the responsibility of
* observers to check which request they are getting notifications for.
*
* Please make sure to update the MozImageLoadingContent WebIDL
* mixin to mirror this interface when changing it.
*/
// We can't make this interface noscript yet, because there is JS code doing
// "instanceof Ci.nsIImageLoadingContent" and using the nsIImageLoadingContent
// constants.
[scriptable, builtinclass, uuid(0357123d-9224-4d12-a47e-868c32689777)]
interface nsIImageLoadingContent : imgINotificationObserver
{
/**
* Request types. Image loading content nodes attempt to do atomic
* image changes when the image url is changed. This means that
* when the url changes the new image load will start, but the old
* image will remain the "current" request until the new image is
* fully loaded. At that point, the old "current" request will be
* discarded and the "pending" request will become "current".
*/
const long UNKNOWN_REQUEST = -1;
const long CURRENT_REQUEST = 0;
const long PENDING_REQUEST = 1;
/**
* setLoadingEnabled is used to enable and disable loading in
* situations where loading images is unwanted. Note that enabling
* loading will *not* automatically trigger an image load.
*/
[notxpcom, nostdcall] void setLoadingEnabled(in boolean aEnabled);
/**
* Used to register an image decoder observer. Typically, this will
* be a proxy for a frame that wants to paint the image.
* Notifications from ongoing image loads will be passed to all
* registered observers. Notifications for all request types,
* current and pending, will be passed through.
*
* @param aObserver the observer to register
*/
[notxpcom, nostdcall] void addNativeObserver(in imgINotificationObserver aObserver);
/**
* Used to unregister an image decoder observer.
*
* @param aObserver the observer to unregister
*/
[notxpcom, nostdcall] void removeNativeObserver(in imgINotificationObserver aObserver);
/**
* Accessor to get the image requests
*
* @param aRequestType a value saying which request is wanted
*
* @return the imgIRequest object (may be null, even when no error
* is thrown)
*
* @throws NS_ERROR_UNEXPECTED if the request type requested is not
* known
*/
[noscript] imgIRequest getRequest(in long aRequestType);
/**
* Used to notify the image loading content node that a frame has been
* created.
*/
[notxpcom] void frameCreated(in nsIFrame aFrame);
/**
* Used to notify the image loading content node that a frame has been
* destroyed.
*/
[notxpcom] void frameDestroyed(in nsIFrame aFrame);
/**
* Used to find out what type of request one is dealing with (eg
* which request got passed through to the imgINotificationObserver
* interface of an observer)
*
* @param aRequest the request whose type we want to know
*
* @return an enum value saying what type this request is
*
* @throws NS_ERROR_UNEXPECTED if aRequest is not known
*/
[noscript] long getRequestType(in imgIRequest aRequest);
/**
* Gets the URI of the current request, if available.
* Otherwise, returns the last URI that this content tried to load, or
* null if there haven't been any such attempts.
*/
[noscript, infallible] readonly attribute nsIURI currentURI;
/**
* Gets the sync-decoding hint set by the decoding attribute.
*/
[noscript, infallible] readonly attribute boolean syncDecodingHint;
/**
* loadImageWithChannel allows data from an existing channel to be
* used as the image data for this content node.
*
* @param aChannel the channel that will deliver the data
*
* @return a stream listener to pump the image data into
*
* @see imgILoader::loadImageWithChannel
*
* @throws NS_ERROR_NULL_POINTER if aChannel is null
*/
[noscript] nsIStreamListener loadImageWithChannel(in nsIChannel aChannel);
/**
* Called by layout to announce when the frame associated with this content
* has changed its visibility state.
*
* @param aNewVisibility The new visibility state.
* @param aNonvisibleAction A requested action if the frame has become
* nonvisible. If Nothing(), no action is
* requested. If DISCARD_IMAGES is specified, the
* frame is requested to ask any images it's
* associated with to discard their surfaces if
* possible.
*/
[noscript, notxpcom] void onVisibilityChange(in Visibility aNewVisibility,
in MaybeOnNonvisible aNonvisibleAction);
};
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