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+/* -*- 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__