1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/image/src/imgDecoderObserver.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,139 @@
1.4 +/** -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
1.5 + * This Source Code Form is subject to the terms of the Mozilla Public
1.6 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.7 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.8 +
1.9 +#ifndef MOZILLA_IMAGELIB_IMGDECODEROBSERVER_H_
1.10 +#define MOZILLA_IMAGELIB_IMGDECODEROBSERVER_H_
1.11 +
1.12 +#include "nsRect.h"
1.13 +#include "mozilla/WeakPtr.h"
1.14 +
1.15 +struct nsIntRect;
1.16 +
1.17 +/**
1.18 + * imgDecoderObserver interface
1.19 + *
1.20 + * This interface is used to observe Decoder objects.
1.21 + *
1.22 + * We make the distinction here between "load" and "decode" notifications. Load
1.23 + * notifications are fired as the image is loaded from the network or
1.24 + * filesystem. Decode notifications are fired as the image is decoded. If an
1.25 + * image is decoded on load and not visibly discarded, decode notifications are
1.26 + * nested logically inside load notifications as one might expect. However, with
1.27 + * decode-on-draw, the set of decode notifications can come completely _after_
1.28 + * the load notifications, and can come multiple times if the image is
1.29 + * discardable. Moreover, they can be interleaved in various ways. In general,
1.30 + * any presumed ordering between load and decode notifications should not be
1.31 + * relied upon.
1.32 + *
1.33 + * Decode notifications may or may not be synchronous, depending on the
1.34 + * situation. If imgIDecoder::FLAG_SYNC_DECODE is passed to a function that
1.35 + * triggers a decode, all notifications that can be generated from the currently
1.36 + * loaded data fire before the call returns. If FLAG_SYNC_DECODE is not passed,
1.37 + * all, some, or none of the notifications may fire before the call returns.
1.38 + */
1.39 +class imgDecoderObserver
1.40 +{
1.41 +public:
1.42 + NS_INLINE_DECL_THREADSAFE_REFCOUNTING(imgDecoderObserver);
1.43 +
1.44 + /**
1.45 + * Load notification.
1.46 + *
1.47 + * called at the same time that nsIRequestObserver::onStartRequest would be
1.48 + * (used only for observers of imgIRequest objects, which are nsIRequests,
1.49 + * not imgIDecoder objects)
1.50 + */
1.51 + virtual void OnStartRequest() = 0;
1.52 +
1.53 + /**
1.54 + * Decode notification.
1.55 + *
1.56 + * Called as soon as the image begins getting decoded. This does not include
1.57 + * "header-only" decodes used by decode-on-draw to parse the width/height
1.58 + * out of the image. Thus, it is a decode notification only.
1.59 + */
1.60 + virtual void OnStartDecode() = 0;
1.61 +
1.62 + /**
1.63 + * Load notification.
1.64 + *
1.65 + * Called once enough data has been loaded from the network that we were able
1.66 + * to parse the width/height from the image. By the time this callback is been
1.67 + * called, the size has been set on the container and STATUS_SIZE_AVAILABLE
1.68 + * has been set on the associated imgRequest.
1.69 + */
1.70 + virtual void OnStartContainer() = 0;
1.71 +
1.72 + /**
1.73 + * Decode notification.
1.74 + *
1.75 + * Called when we know a frame has begun decoding.
1.76 + */
1.77 + virtual void OnStartFrame() = 0;
1.78 +
1.79 + /**
1.80 + * Decode notification.
1.81 + *
1.82 + * called when there is more to paint.
1.83 + */
1.84 + virtual void FrameChanged(const nsIntRect * aDirtyRect) = 0;
1.85 +
1.86 + /**
1.87 + * Decode notification.
1.88 + *
1.89 + * called when a frame is finished decoding.
1.90 + */
1.91 + virtual void OnStopFrame() = 0;
1.92 +
1.93 + /**
1.94 + * Notification for when an image is known to be animated. This should be
1.95 + * fired at the earliest possible time.
1.96 + */
1.97 + virtual void OnImageIsAnimated() = 0;
1.98 +
1.99 + /**
1.100 + * Decode notification.
1.101 + *
1.102 + * Called when all decoding has terminated.
1.103 + */
1.104 + virtual void OnStopDecode(nsresult status) = 0;
1.105 +
1.106 + /**
1.107 + * Load notification.
1.108 + *
1.109 + * called at the same time that nsIRequestObserver::onStopRequest would be
1.110 + * (used only for observers of imgIRequest objects, which are nsIRequests,
1.111 + * not imgIDecoder objects)
1.112 + */
1.113 + virtual void OnStopRequest(bool aIsLastPart, nsresult aStatus) = 0;
1.114 +
1.115 + /**
1.116 + * Called when the decoded image data is discarded. This means that the frames
1.117 + * no longer exist in decoded form, and any attempt to access or draw the
1.118 + * image will initiate a new series of progressive decode notifications.
1.119 + */
1.120 + virtual void OnDiscard() = 0;
1.121 +
1.122 + /**
1.123 + * Called when we are asked to Draw an image that is not locked.
1.124 + */
1.125 + virtual void OnUnlockedDraw() = 0;
1.126 +
1.127 + /**
1.128 + * Called when an image is realized to be in error state.
1.129 + */
1.130 + virtual void OnError() = 0;
1.131 +
1.132 +protected:
1.133 + virtual ~imgDecoderObserver() = 0;
1.134 +};
1.135 +
1.136 +// We must define a destructor because derived classes call our destructor from
1.137 +// theirs. Pure virtual destructors only requires that child classes implement
1.138 +// a virtual destructor, not that we can't have one too!
1.139 +inline imgDecoderObserver::~imgDecoderObserver()
1.140 +{}
1.141 +
1.142 +#endif // MOZILLA_IMAGELIB_IMGDECODEROBSERVER_H
