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Diffstat (limited to 'dom/base/nsImageLoadingContent.h')
| -rw-r--r-- | dom/base/nsImageLoadingContent.h | 462 |
1 files changed, 462 insertions, 0 deletions
diff --git a/dom/base/nsImageLoadingContent.h b/dom/base/nsImageLoadingContent.h new file mode 100644 index 000000000..85db2bd2c --- /dev/null +++ b/dom/base/nsImageLoadingContent.h @@ -0,0 +1,462 @@ +/* -*- 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 "imgIOnloadBlocker.h" +#include "mozilla/CORSMode.h" +#include "mozilla/EventStates.h" +#include "mozilla/TimeStamp.h" +#include "nsCOMPtr.h" +#include "nsIImageLoadingContent.h" +#include "nsIRequest.h" +#include "mozilla/ErrorResult.h" +#include "nsIContentPolicy.h" +#include "mozilla/dom/BindingDeclarations.h" +#include "mozilla/net/ReferrerPolicy.h" + +class nsIURI; +class nsIDocument; +class nsPresContext; +class nsIContent; +class imgRequestProxy; + +namespace mozilla { +class AsyncEventDispatcher; +} // namespace mozilla + +#ifdef LoadImage +// Undefine LoadImage to prevent naming conflict with Windows. +#undef LoadImage +#endif + +class nsImageLoadingContent : public nsIImageLoadingContent, + public imgIOnloadBlocker +{ + 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 + NS_DECL_IMGIONLOADBLOCKER + + // Web IDL binding methods. + // Note that the XPCOM SetLoadingEnabled, AddObserver, RemoveObserver, + // 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; } + int16_t ImageBlockingStatus() const + { + return mImageBlockingStatus; + } + already_AddRefed<imgIRequest> + GetRequest(int32_t aRequestType, mozilla::ErrorResult& aError); + int32_t + GetRequestType(imgIRequest* aRequest, mozilla::ErrorResult& aError); + already_AddRefed<nsIURI> GetCurrentURI(mozilla::ErrorResult& aError); + void ForceReload(const mozilla::dom::Optional<bool>& aNotify, + mozilla::ErrorResult& aError); + + // XPCOM [optional] syntax helper + nsresult ForceReload(bool aNotify = true) { + return ForceReload(aNotify, 1); + } + +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 + */ + nsresult LoadImage(const nsAString& aNewURI, bool aForce, + bool aNotify, ImageLoadType aImageLoadType); + + /** + * ImageState is called by subclasses that are computing their content state. + * The return value will have the NS_EVENT_STATE_BROKEN, + * NS_EVENT_STATE_USERDISABLED, and NS_EVENT_STATE_SUPPRESSED bits 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 + */ + nsresult LoadImage(nsIURI* aNewURI, bool aForce, bool aNotify, + ImageLoadType aImageLoadType, bool aLoadStart = true, + nsIDocument* aDocument = nullptr, + nsLoadFlags aLoadFlags = nsIRequest::LOAD_NORMAL); + + /** + * 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 + */ + nsIDocument* GetOurOwnerDoc(); + nsIDocument* 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); + + /** + * UseAsPrimaryRequest is called by subclasses when they have an existing + * imgRequestProxy that they want this nsImageLoadingContent to use. This may + * effectively be called instead of LoadImage or LoadImageWithChannel. + * If aNotify is true, this method will notify on state changes. + */ + nsresult UseAsPrimaryRequest(imgRequestProxy* aRequest, bool aNotify, + ImageLoadType aImageLoadType); + + /** + * Derived classes of nsImageLoadingContent MUST call + * DestroyImageLoadingContent 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 DestroyImageLoadingContent(); + + void ClearBrokenState() { mBroken = false; } + + /** + * Returns the CORS mode that will be used for all future image loads. The + * default implementation returns CORS_NONE unconditionally. + */ + virtual mozilla::CORSMode GetCORSMode(); + + virtual mozilla::net::ReferrerPolicy GetImageReferrerPolicy(); + + // Subclasses are *required* to call BindToTree/UnbindFromTree. + void BindToTree(nsIDocument* aDocument, nsIContent* aParent, + nsIContent* aBindingParent, bool aCompileEventHandlers); + void UnbindFromTree(bool aDeep, bool aNullParent); + + nsresult OnLoadComplete(imgIRequest* aRequest, nsresult aStatus); + void OnUnlockedDraw(); + nsresult OnImageIsAnimated(imgIRequest *aRequest); + + // The nsContentPolicyType we would use for this ImageLoadType + static nsContentPolicyType PolicyTypeForLoad(ImageLoadType aImageLoadType); + + void AsyncEventRunning(mozilla::AsyncEventDispatcher* aEvent); + +private: + /** + * Struct used to manage the image observers. + */ + struct ImageObserver { + explicit ImageObserver(imgINotificationObserver* aObserver); + ~ImageObserver(); + + nsCOMPtr<imgINotificationObserver> mObserver; + ImageObserver* mNext; + }; + + /** + * 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; + + /** + * 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 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: + /** + * 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, nsIDocument* aDocument, + nsIURI** aURI); + + void CreateStaticImageClone(nsImageLoadingContent* aDest) const; + + /** + * 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); + + /** + * Called when we would normally call PrepareNextRequest(), but the request was + * blocked. + */ + void SetBlockedRequest(nsIURI* aURI, int16_t aContentDecision); + + /** + * 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, since it passes a more appropriate + * aReason than Prepare*Request() does (NS_ERROR_IMAGE_SRC_CHANGED). + * + * @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 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); + void UntrackImage(imgIRequest* aImage, + const Maybe<OnNonvisible>& aNonvisibleAction = Nothing()); + + /* 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 blocking onload. + REQUEST_BLOCKS_ONLOAD = 0x00000002U, + // 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: + /** + * 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; + + /** + * When mIsImageStateForced is true, this holds the ImageState that we'll + * return in ImageState(). + */ + mozilla::EventStates mForcedImageState; + + mozilla::TimeStamp mMostRecentRequestChange; + + int16_t mImageBlockingStatus; + 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; + bool mUserDisabled : 1; + bool mSuppressed : 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; + +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; + + // True when FrameCreate has been called but FrameDestroy has not. + bool mFrameCreateCalled; +}; + +#endif // nsImageLoadingContent_h__ |