image/src/imgDecoderObserver.h@b8a032363ba2 (annotated)
image/src/imgDecoderObserver.h
Thu, 22 Jan 2015 13:21:57 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Thu, 22 Jan 2015 13:21:57 +0100
- branch
- TOR_BUG_9701
- changeset 15
- b8a032363ba2
- permissions
- -rw-r--r--
Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6
| michael@0 | 1 | /** -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- |
| michael@0 | 2 | * This Source Code Form is subject to the terms of the Mozilla Public |
| michael@0 | 3 | * License, v. 2.0. If a copy of the MPL was not distributed with this |
| michael@0 | 4 | * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ |
| michael@0 | 5 | |
| michael@0 | 6 | #ifndef MOZILLA_IMAGELIB_IMGDECODEROBSERVER_H_ |
| michael@0 | 7 | #define MOZILLA_IMAGELIB_IMGDECODEROBSERVER_H_ |
| michael@0 | 8 | |
| michael@0 | 9 | #include "nsRect.h" |
| michael@0 | 10 | #include "mozilla/WeakPtr.h" |
| michael@0 | 11 | |
| michael@0 | 12 | struct nsIntRect; |
| michael@0 | 13 | |
| michael@0 | 14 | /** |
| michael@0 | 15 | * imgDecoderObserver interface |
| michael@0 | 16 | * |
| michael@0 | 17 | * This interface is used to observe Decoder objects. |
| michael@0 | 18 | * |
| michael@0 | 19 | * We make the distinction here between "load" and "decode" notifications. Load |
| michael@0 | 20 | * notifications are fired as the image is loaded from the network or |
| michael@0 | 21 | * filesystem. Decode notifications are fired as the image is decoded. If an |
| michael@0 | 22 | * image is decoded on load and not visibly discarded, decode notifications are |
| michael@0 | 23 | * nested logically inside load notifications as one might expect. However, with |
| michael@0 | 24 | * decode-on-draw, the set of decode notifications can come completely _after_ |
| michael@0 | 25 | * the load notifications, and can come multiple times if the image is |
| michael@0 | 26 | * discardable. Moreover, they can be interleaved in various ways. In general, |
| michael@0 | 27 | * any presumed ordering between load and decode notifications should not be |
| michael@0 | 28 | * relied upon. |
| michael@0 | 29 | * |
| michael@0 | 30 | * Decode notifications may or may not be synchronous, depending on the |
| michael@0 | 31 | * situation. If imgIDecoder::FLAG_SYNC_DECODE is passed to a function that |
| michael@0 | 32 | * triggers a decode, all notifications that can be generated from the currently |
| michael@0 | 33 | * loaded data fire before the call returns. If FLAG_SYNC_DECODE is not passed, |
| michael@0 | 34 | * all, some, or none of the notifications may fire before the call returns. |
| michael@0 | 35 | */ |
| michael@0 | 36 | class imgDecoderObserver |
| michael@0 | 37 | { |
| michael@0 | 38 | public: |
| michael@0 | 39 | NS_INLINE_DECL_THREADSAFE_REFCOUNTING(imgDecoderObserver); |
| michael@0 | 40 | |
| michael@0 | 41 | /** |
| michael@0 | 42 | * Load notification. |
| michael@0 | 43 | * |
| michael@0 | 44 | * called at the same time that nsIRequestObserver::onStartRequest would be |
| michael@0 | 45 | * (used only for observers of imgIRequest objects, which are nsIRequests, |
| michael@0 | 46 | * not imgIDecoder objects) |
| michael@0 | 47 | */ |
| michael@0 | 48 | virtual void OnStartRequest() = 0; |
| michael@0 | 49 | |
| michael@0 | 50 | /** |
| michael@0 | 51 | * Decode notification. |
| michael@0 | 52 | * |
| michael@0 | 53 | * Called as soon as the image begins getting decoded. This does not include |
| michael@0 | 54 | * "header-only" decodes used by decode-on-draw to parse the width/height |
| michael@0 | 55 | * out of the image. Thus, it is a decode notification only. |
| michael@0 | 56 | */ |
| michael@0 | 57 | virtual void OnStartDecode() = 0; |
| michael@0 | 58 | |
| michael@0 | 59 | /** |
| michael@0 | 60 | * Load notification. |
| michael@0 | 61 | * |
| michael@0 | 62 | * Called once enough data has been loaded from the network that we were able |
| michael@0 | 63 | * to parse the width/height from the image. By the time this callback is been |
| michael@0 | 64 | * called, the size has been set on the container and STATUS_SIZE_AVAILABLE |
| michael@0 | 65 | * has been set on the associated imgRequest. |
| michael@0 | 66 | */ |
| michael@0 | 67 | virtual void OnStartContainer() = 0; |
| michael@0 | 68 | |
| michael@0 | 69 | /** |
| michael@0 | 70 | * Decode notification. |
| michael@0 | 71 | * |
| michael@0 | 72 | * Called when we know a frame has begun decoding. |
| michael@0 | 73 | */ |
| michael@0 | 74 | virtual void OnStartFrame() = 0; |
| michael@0 | 75 | |
| michael@0 | 76 | /** |
| michael@0 | 77 | * Decode notification. |
| michael@0 | 78 | * |
| michael@0 | 79 | * called when there is more to paint. |
| michael@0 | 80 | */ |
| michael@0 | 81 | virtual void FrameChanged(const nsIntRect * aDirtyRect) = 0; |
| michael@0 | 82 | |
| michael@0 | 83 | /** |
| michael@0 | 84 | * Decode notification. |
| michael@0 | 85 | * |
| michael@0 | 86 | * called when a frame is finished decoding. |
| michael@0 | 87 | */ |
| michael@0 | 88 | virtual void OnStopFrame() = 0; |
| michael@0 | 89 | |
| michael@0 | 90 | /** |
| michael@0 | 91 | * Notification for when an image is known to be animated. This should be |
| michael@0 | 92 | * fired at the earliest possible time. |
| michael@0 | 93 | */ |
| michael@0 | 94 | virtual void OnImageIsAnimated() = 0; |
| michael@0 | 95 | |
| michael@0 | 96 | /** |
| michael@0 | 97 | * Decode notification. |
| michael@0 | 98 | * |
| michael@0 | 99 | * Called when all decoding has terminated. |
| michael@0 | 100 | */ |
| michael@0 | 101 | virtual void OnStopDecode(nsresult status) = 0; |
| michael@0 | 102 | |
| michael@0 | 103 | /** |
| michael@0 | 104 | * Load notification. |
| michael@0 | 105 | * |
| michael@0 | 106 | * called at the same time that nsIRequestObserver::onStopRequest would be |
| michael@0 | 107 | * (used only for observers of imgIRequest objects, which are nsIRequests, |
| michael@0 | 108 | * not imgIDecoder objects) |
| michael@0 | 109 | */ |
| michael@0 | 110 | virtual void OnStopRequest(bool aIsLastPart, nsresult aStatus) = 0; |
| michael@0 | 111 | |
| michael@0 | 112 | /** |
| michael@0 | 113 | * Called when the decoded image data is discarded. This means that the frames |
| michael@0 | 114 | * no longer exist in decoded form, and any attempt to access or draw the |
| michael@0 | 115 | * image will initiate a new series of progressive decode notifications. |
| michael@0 | 116 | */ |
| michael@0 | 117 | virtual void OnDiscard() = 0; |
| michael@0 | 118 | |
| michael@0 | 119 | /** |
| michael@0 | 120 | * Called when we are asked to Draw an image that is not locked. |
| michael@0 | 121 | */ |
| michael@0 | 122 | virtual void OnUnlockedDraw() = 0; |
| michael@0 | 123 | |
| michael@0 | 124 | /** |
| michael@0 | 125 | * Called when an image is realized to be in error state. |
| michael@0 | 126 | */ |
| michael@0 | 127 | virtual void OnError() = 0; |
| michael@0 | 128 | |
| michael@0 | 129 | protected: |
| michael@0 | 130 | virtual ~imgDecoderObserver() = 0; |
| michael@0 | 131 | }; |
| michael@0 | 132 | |
| michael@0 | 133 | // We must define a destructor because derived classes call our destructor from |
| michael@0 | 134 | // theirs. Pure virtual destructors only requires that child classes implement |
| michael@0 | 135 | // a virtual destructor, not that we can't have one too! |
| michael@0 | 136 | inline imgDecoderObserver::~imgDecoderObserver() |
| michael@0 | 137 | {} |
| michael@0 | 138 | |
| michael@0 | 139 | #endif // MOZILLA_IMAGELIB_IMGDECODEROBSERVER_H |
