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