nsImageLoadingContent.h
/* -*- 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);
}
/**
* Used to initialize content with a previously opened channel. Assumes
* eImageLoadType_Normal
*/
already_AddRefed<nsIStreamListener>
LoadImageWithChannel(nsIChannel* aChannel, mozilla::ErrorResult& aError);
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 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, 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__
