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| -rw-r--r-- | dom/base/nsImageLoadingContent.h | 633 |
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diff --git a/dom/base/nsImageLoadingContent.h b/dom/base/nsImageLoadingContent.h new file mode 100644 index 0000000000..ec4286bed9 --- /dev/null +++ b/dom/base/nsImageLoadingContent.h @@ -0,0 +1,633 @@ +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ +/* vim: set ts=8 sts=2 et sw=2 tw=80: */ +/* 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/. */ + +/* + * A base class which implements nsIImageLoadingContent and can be + * subclassed by various content nodes that want to provide image + * loading functionality (eg <img>, <object>, etc). + */ + +#ifndef nsImageLoadingContent_h__ +#define nsImageLoadingContent_h__ + +#include "imgINotificationObserver.h" +#include "mozilla/CORSMode.h" +#include "mozilla/EventStates.h" +#include "mozilla/TimeStamp.h" +#include "nsCOMPtr.h" +#include "nsIContentPolicy.h" +#include "nsIImageLoadingContent.h" +#include "nsIRequest.h" +#include "mozilla/dom/BindingDeclarations.h" +#include "mozilla/dom/Promise.h" +#include "nsAttrValue.h" +#include "Units.h" + +class nsINode; +class nsIURI; +class nsPresContext; +class nsIContent; +class imgRequestProxy; + +namespace mozilla { +class AsyncEventDispatcher; +class ErrorResult; + +namespace dom { +struct BindContext; +class Document; +class Element; +} // namespace dom +} // namespace mozilla + +#ifdef LoadImage +// Undefine LoadImage to prevent naming conflict with Windows. +# undef LoadImage +#endif + +class nsImageLoadingContent : public nsIImageLoadingContent { + protected: + template <typename T> + using Maybe = mozilla::Maybe<T>; + using Nothing = mozilla::Nothing; + using OnNonvisible = mozilla::OnNonvisible; + using Visibility = mozilla::Visibility; + + /* METHODS */ + public: + nsImageLoadingContent(); + virtual ~nsImageLoadingContent(); + + NS_DECL_IMGINOTIFICATIONOBSERVER + NS_DECL_NSIIMAGELOADINGCONTENT + + // Web IDL binding methods. + // Note that the XPCOM SetLoadingEnabled, ForceImageState methods are OK for + // Web IDL bindings to use as well, since none of them throw when called via + // the Web IDL bindings. + + bool LoadingEnabled() const { return mLoadingEnabled; } + void AddObserver(imgINotificationObserver* aObserver); + void RemoveObserver(imgINotificationObserver* aObserver); + already_AddRefed<imgIRequest> GetRequest(int32_t aRequestType, + mozilla::ErrorResult& aError); + int32_t GetRequestType(imgIRequest* aRequest, mozilla::ErrorResult& aError); + already_AddRefed<nsIURI> GetCurrentURI(); + already_AddRefed<nsIURI> GetCurrentRequestFinalURI(); + void ForceReload(bool aNotify, mozilla::ErrorResult& aError); + + mozilla::dom::Element* FindImageMap(); + + /** + * Toggle whether or not to synchronously decode an image on draw. + */ + void SetSyncDecodingHint(bool aHint); + + /** + * Notify us that the document state has changed. Called by nsDocument so that + * we may reject any promises which require the document to be active. + */ + void NotifyOwnerDocumentActivityChanged(); + + protected: + enum ImageLoadType { + // Most normal image loads + eImageLoadType_Normal, + // From a <img srcset> or <picture> context. Affects type given to content + // policy. + eImageLoadType_Imageset + }; + + /** + * LoadImage is called by subclasses when the appropriate + * attributes (eg 'src' for <img> tags) change. The string passed + * in is the new uri string; this consolidates the code for getting + * the charset, constructing URI objects, and any other incidentals + * into this superclass. + * + * @param aNewURI the URI spec to be loaded (may be a relative URI) + * @param aForce If true, make sure to load the URI. If false, only + * load if the URI is different from the currently loaded URI. + * @param aNotify If true, nsIDocumentObserver state change notifications + * will be sent as needed. + * @param aImageLoadType The ImageLoadType for this request + * @param aTriggeringPrincipal Optional parameter specifying the triggering + * principal to use for the image load + */ + nsresult LoadImage(const nsAString& aNewURI, bool aForce, bool aNotify, + ImageLoadType aImageLoadType, + nsIPrincipal* aTriggeringPrincipal = nullptr); + + /** + * ImageState is called by subclasses that are computing their content state. + * The return value will have the NS_EVENT_STATE_BROKEN bit set as needed. + * + * Note that this state assumes that this node is "trying" to be an + * image (so for example complete lack of attempt to load an image will lead + * to NS_EVENT_STATE_BROKEN being set). Subclasses that are not "trying" to + * be an image (eg an HTML <input> of type other than "image") should just + * not call this method when computing their intrinsic state. + */ + mozilla::EventStates ImageState() const; + + /** + * LoadImage is called by subclasses when the appropriate + * attributes (eg 'src' for <img> tags) change. If callers have an + * URI object already available, they should use this method. + * + * @param aNewURI the URI to be loaded + * @param aForce If true, make sure to load the URI. If false, only + * load if the URI is different from the currently loaded URI. + * @param aNotify If true, nsIDocumentObserver state change notifications + * will be sent as needed. + * @param aImageLoadType The ImageLoadType for this request + * @param aLoadStart If true, dispatch "loadstart" event. + * @param aDocument Optional parameter giving the document this node is in. + * This is purely a performance optimization. + * @param aLoadFlags Optional parameter specifying load flags to use for + * the image load + * @param aTriggeringPrincipal Optional parameter specifying the triggering + * principal to use for the image load + */ + nsresult LoadImage(nsIURI* aNewURI, bool aForce, bool aNotify, + ImageLoadType aImageLoadType, nsLoadFlags aLoadFlags, + bool aLoadStart = true, + mozilla::dom::Document* aDocument = nullptr, + nsIPrincipal* aTriggeringPrincipal = nullptr); + + nsresult LoadImage(nsIURI* aNewURI, bool aForce, bool aNotify, + ImageLoadType aImageLoadType, + nsIPrincipal* aTriggeringPrincipal) { + return LoadImage(aNewURI, aForce, aNotify, aImageLoadType, LoadFlags(), + true, nullptr, aTriggeringPrincipal); + } + + /** + * helpers to get the document for this content (from the nodeinfo + * and such). Not named GetOwnerDoc/GetCurrentDoc to prevent ambiguous + * method names in subclasses + * + * @return the document we belong to + */ + mozilla::dom::Document* GetOurOwnerDoc(); + mozilla::dom::Document* GetOurCurrentDoc(); + + /** + * Helper function to get the frame associated with this content. Not named + * GetPrimaryFrame to prevent ambiguous method names in subclasses. + * + * @return The frame which we belong to, or nullptr if it doesn't exist. + */ + nsIFrame* GetOurPrimaryFrame(); + + /** + * Helper function to get the PresContext associated with this content's + * frame. Not named GetPresContext to prevent ambiguous method names in + * subclasses. + * + * @return The nsPresContext associated with our frame, or nullptr if either + * the frame doesn't exist, or the frame's prescontext doesn't exist. + */ + nsPresContext* GetFramePresContext(); + + /** + * CancelImageRequests is called by subclasses when they want to + * cancel all image requests (for example when the subclass is + * somehow not an image anymore). + */ + void CancelImageRequests(bool aNotify); + + /** + * Derived classes of nsImageLoadingContent MUST call Destroy from their + * destructor, or earlier. It does things that cannot be done in + * ~nsImageLoadingContent because they rely on being able to QueryInterface to + * other derived classes, which cannot happen once the derived class + * destructor has started calling the base class destructors. + */ + void Destroy(); + + /** + * Returns the CORS mode that will be used for all future image loads. The + * default implementation returns CORS_NONE unconditionally. + */ + virtual mozilla::CORSMode GetCORSMode(); + + // Subclasses are *required* to call BindToTree/UnbindFromTree. + void BindToTree(mozilla::dom::BindContext&, nsINode& aParent); + void UnbindFromTree(bool aNullParent); + + void OnLoadComplete(imgIRequest* aRequest, nsresult aStatus); + void OnUnlockedDraw(); + void OnImageIsAnimated(imgIRequest* aRequest); + + // The nsContentPolicyType we would use for this ImageLoadType + static nsContentPolicyType PolicyTypeForLoad(ImageLoadType aImageLoadType); + + void AsyncEventRunning(mozilla::AsyncEventDispatcher* aEvent); + + // Get ourselves as an nsIContent*. Not const because some of the callers + // want a non-const nsIContent. + virtual nsIContent* AsContent() = 0; + + // Hooks for subclasses to call to get the intrinsic width and height. + uint32_t NaturalWidth(); + uint32_t NaturalHeight(); + /** + * Get width and height of the current request, using given image request if + * attributes are unset. + */ + MOZ_CAN_RUN_SCRIPT mozilla::CSSIntSize GetWidthHeightForImage(); + + /** + * Create a promise and queue a microtask which will ensure the current + * request (after any pending loads are applied) has requested a full decode. + * The promise is fulfilled once the request has a fully decoded surface that + * is available for drawing, or an error condition occurrs (e.g. broken image, + * current request is updated, etc). + * + * https://html.spec.whatwg.org/multipage/embedded-content.html#dom-img-decode + */ + already_AddRefed<mozilla::dom::Promise> QueueDecodeAsync( + mozilla::ErrorResult& aRv); + + enum class ImageDecodingType : uint8_t { + Auto, + Async, + Sync, + }; + + static const nsAttrValue::EnumTable kDecodingTable[]; + static const nsAttrValue::EnumTable* kDecodingTableDefault; + + private: + /** + * Enqueue and/or fulfill a promise created by QueueDecodeAsync. + */ + void DecodeAsync(RefPtr<mozilla::dom::Promise>&& aPromise, + uint32_t aRequestGeneration); + + /** + * Attempt to resolve all queued promises based on the state of the current + * request. If the current request does not yet have all of the encoded data, + * or the decoding has not yet completed, it will return without changing the + * promise states. + */ + void MaybeResolveDecodePromises(); + + /** + * Reject all queued promises with the given status. + */ + void RejectDecodePromises(nsresult aStatus); + + /** + * Age the generation counter if we have a new current request with a + * different URI. If the generation counter is aged, then all queued promises + * will also be rejected. + */ + void MaybeAgeRequestGeneration(nsIURI* aNewURI); + + /** + * Deregister as an observer for the owner document's activity notifications + * if we have no outstanding decode promises. + */ + void MaybeDeregisterActivityObserver(); + + /** + * Struct used to manage the native image observers. + */ + struct ImageObserver { + explicit ImageObserver(imgINotificationObserver* aObserver); + ~ImageObserver(); + + nsCOMPtr<imgINotificationObserver> mObserver; + ImageObserver* mNext; + }; + + /** + * Struct used to manage the scripted/XPCOM image observers. + */ + class ScriptedImageObserver final { + public: + NS_INLINE_DECL_REFCOUNTING(ScriptedImageObserver) + + ScriptedImageObserver(imgINotificationObserver* aObserver, + RefPtr<imgRequestProxy>&& aCurrentRequest, + RefPtr<imgRequestProxy>&& aPendingRequest); + bool CancelRequests(); + + nsCOMPtr<imgINotificationObserver> mObserver; + RefPtr<imgRequestProxy> mCurrentRequest; + RefPtr<imgRequestProxy> mPendingRequest; + + private: + ~ScriptedImageObserver(); + }; + + /** + * Struct to report state changes + */ + struct AutoStateChanger { + AutoStateChanger(nsImageLoadingContent* aImageContent, bool aNotify) + : mImageContent(aImageContent), mNotify(aNotify) { + mImageContent->mStateChangerDepth++; + } + ~AutoStateChanger() { + mImageContent->mStateChangerDepth--; + mImageContent->UpdateImageState(mNotify); + } + + nsImageLoadingContent* mImageContent; + bool mNotify; + }; + + friend struct AutoStateChanger; + + /** + * Method to fire an event once we know what's going on with the image load. + * + * @param aEventType "loadstart", "loadend", "load", or "error" depending on + * how things went + * @param aIsCancelable true if event is cancelable. + */ + nsresult FireEvent(const nsAString& aEventType, bool aIsCancelable = false); + + /** + * Method to cancel and null-out pending event if they exist. + */ + void CancelPendingEvent(); + + RefPtr<mozilla::AsyncEventDispatcher> mPendingEvent; + + protected: + /** + * UpdateImageState recomputes the current state of this image loading + * content and updates what ImageState() returns accordingly. It will also + * fire a ContentStatesChanged() notification as needed if aNotify is true. + */ + void UpdateImageState(bool aNotify); + + /** + * Method to create an nsIURI object from the given string (will + * handle getting the right charset, base, etc). You MUST pass in a + * non-null document to this function. + * + * @param aSpec the string spec (from an HTML attribute, eg) + * @param aDocument the document we belong to + * @return the URI we want to be loading + */ + nsresult StringToURI(const nsAString& aSpec, + mozilla::dom::Document* aDocument, nsIURI** aURI); + + /** + * Prepare and returns a reference to the "next request". If there's already + * a _usable_ current request (one with SIZE_AVAILABLE), this request is + * "pending" until it becomes usable. Otherwise, this becomes the current + * request. + * + * @param aImageLoadType The ImageLoadType for this request + */ + RefPtr<imgRequestProxy>& PrepareNextRequest(ImageLoadType aImageLoadType); + + /** + * Returns a COMPtr reference to the current/pending image requests, cleaning + * up and canceling anything that was there before. Note that if you just want + * to get rid of one of the requests, you should call + * Clear*Request(NS_BINDING_ABORTED) instead. + * + * @param aImageLoadType The ImageLoadType for this request + */ + RefPtr<imgRequestProxy>& PrepareCurrentRequest(ImageLoadType aImageLoadType); + RefPtr<imgRequestProxy>& PreparePendingRequest(ImageLoadType aImageLoadType); + + /** + * Switch our pending request to be our current request. + * mPendingRequest must be non-null! + */ + void MakePendingRequestCurrent(); + + /** + * Cancels and nulls-out the "current" and "pending" requests if they exist. + * + * @param aNonvisibleAction An action to take if the image is no longer + * visible as a result; see |UntrackImage|. + */ + void ClearCurrentRequest( + nsresult aReason, + const Maybe<OnNonvisible>& aNonvisibleAction = Nothing()); + void ClearPendingRequest( + nsresult aReason, + const Maybe<OnNonvisible>& aNonvisibleAction = Nothing()); + + /** + * Retrieve a pointer to the 'registered with the refresh driver' flag for + * which a particular image request corresponds. + * + * @returns A pointer to the boolean flag for a given image request, or + * |nullptr| if the request is not either |mPendingRequest| or + * |mCurrentRequest|. + */ + bool* GetRegisteredFlagForRequest(imgIRequest* aRequest); + + /** + * Reset animation of the current request if + * |mNewRequestsWillNeedAnimationReset| was true when the request was + * prepared. + */ + void ResetAnimationIfNeeded(); + + /** + * Static helper method to tell us if we have the size of a request. The + * image may be null. + */ + static bool HaveSize(imgIRequest* aImage); + + /** + * Adds/Removes a given imgIRequest from our document's tracker. + * + * No-op if aImage is null. + * + * @param aFrame If called from FrameCreated the frame passed to FrameCreated. + * This is our frame, but at the time of the FrameCreated call + * our primary frame pointer hasn't been set yet, so this is + * only way to get our frame. + * + * @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. + */ + void TrackImage(imgIRequest* aImage, nsIFrame* aFrame = nullptr); + void UntrackImage(imgIRequest* aImage, + const Maybe<OnNonvisible>& aNonvisibleAction = Nothing()); + + nsLoadFlags LoadFlags(); + + /* MEMBERS */ + RefPtr<imgRequestProxy> mCurrentRequest; + RefPtr<imgRequestProxy> mPendingRequest; + uint32_t mCurrentRequestFlags; + uint32_t mPendingRequestFlags; + + enum { + // Set if the request needs ResetAnimation called on it. + REQUEST_NEEDS_ANIMATION_RESET = 0x00000001U, + // Set if the request is currently tracked with the document. + REQUEST_IS_TRACKED = 0x00000004U, + // Set if this is an imageset request, such as from <img srcset> or + // <picture> + REQUEST_IS_IMAGESET = 0x00000008U + }; + + // If the image was blocked or if there was an error loading, it's nice to + // still keep track of what the URI was despite not having an imgIRequest. + // We only maintain this in those situations (in the common case, this is + // always null). + nsCOMPtr<nsIURI> mCurrentURI; + + private: + /** + * Clones the given "current" or "pending" request for each scripted observer. + */ + void CloneScriptedRequests(imgRequestProxy* aRequest); + + /** + * Cancels and nulls-out the "current" or "pending" requests if they exist + * for each scripted observer. + */ + void ClearScriptedRequests(int32_t aRequestType, nsresult aReason); + + /** + * Moves the "pending" request into the "current" request for each scripted + * observer. If there is an existing "current" request, it will cancel it + * first. + */ + void MakePendingScriptedRequestsCurrent(); + + /** + * Depending on the configured decoding hint, and/or how recently we updated + * the image request, force or stop the frame from decoding the image + * synchronously when it is drawn. + * @param aPrepareNextRequest True if this is when updating the image request. + * @param aFrame If called from FrameCreated the frame passed to FrameCreated. + * This is our frame, but at the time of the FrameCreated call + * our primary frame pointer hasn't been set yet, so this is + * only way to get our frame. + */ + void MaybeForceSyncDecoding(bool aPrepareNextRequest, + nsIFrame* aFrame = nullptr); + + /** + * Typically we will have only one observer (our frame in the screen + * prescontext), so we want to only make space for one and to + * heap-allocate anything past that (saves memory and malloc churn + * in the common case). The storage is a linked list, we just + * happen to actually hold the first observer instead of a pointer + * to it. + */ + ImageObserver mObserverList; + + /** + * Typically we will have no scripted observers, as this is only used by + * chrome, legacy extensions, and some mochitests. An empty array reserves + * minimal memory. + */ + nsTArray<RefPtr<ScriptedImageObserver>> mScriptedObservers; + + /** + * Promises created by QueueDecodeAsync that are still waiting to be + * fulfilled by the image being fully decoded. + */ + nsTArray<RefPtr<mozilla::dom::Promise>> mDecodePromises; + + /** + * When mIsImageStateForced is true, this holds the ImageState that we'll + * return in ImageState(). + */ + mozilla::EventStates mForcedImageState; + + mozilla::TimeStamp mMostRecentRequestChange; + + /** + * Total number of outstanding decode promises, including those stored in + * mDecodePromises and those embedded in runnables waiting to be enqueued. + * This is used to determine whether we need to register as an observer for + * document activity notifications. + */ + size_t mOutstandingDecodePromises; + + /** + * An incrementing counter representing the current request generation; + * Each time mCurrentRequest is modified with a different URI, this will + * be incremented. Each QueueDecodeAsync call will cache the generation + * of the current request so that when it is processed, it knows if it + * should have rejected because the request changed. + */ + uint32_t mRequestGeneration; + + bool mLoadingEnabled : 1; + + /** + * When true, we return mForcedImageState from ImageState(). + */ + bool mIsImageStateForced : 1; + + /** + * The state we had the last time we checked whether we needed to notify the + * document of a state change. These are maintained by UpdateImageState. + */ + bool mLoading : 1; + bool mBroken : 1; + + protected: + /** + * A hack to get animations to reset, see bug 594771. On requests + * that originate from setting .src, we mark them for needing their animation + * reset when they are ready. mNewRequestsWillNeedAnimationReset is set to + * true while preparing such requests (as a hack around needing to change an + * interface), and the other two booleans store which of the current + * and pending requests are of the sort that need their animation restarted. + */ + bool mNewRequestsWillNeedAnimationReset : 1; + + /** + * Flag to indicate whether the channel should be mark as urgent-start. + * It should be set in *Element and passed to nsContentUtils::LoadImage. + * True if we want to set nsIClassOfService::UrgentStart to the channel to + * get the response ASAP for better user responsiveness. + */ + bool mUseUrgentStartForChannel : 1; + + // Represents the image is deferred loading until this element gets visible. + bool mLazyLoading : 1; + + private: + /* The number of nested AutoStateChangers currently tracking our state. */ + uint8_t mStateChangerDepth; + + // Flags to indicate whether each of the current and pending requests are + // registered with the refresh driver. + bool mCurrentRequestRegistered; + bool mPendingRequestRegistered; + + // TODO: + // Bug 1353685: Should ServiceWorker call SetBlockedRequest? + // + // This member is used in SetBlockedRequest, if it's true, then this call is + // triggered from LoadImage. + // If this is false, it means this call is from other places like + // ServiceWorker, then we will ignore call to SetBlockedRequest for now. + // + // Also we use this variable to check if some evil code is reentering + // LoadImage. + bool mIsStartingImageLoad; + + // If true, force frames to synchronously decode images on draw. + bool mSyncDecodingHint; +}; + +#endif // nsImageLoadingContent_h__ |