The Tor Browser: content/base/src/nsImageLoadingContent.h@6474c204b198 (annotated)

content/base/src/nsImageLoadingContent.h@6474c204b198 (annotated)

content/base/src/nsImageLoadingContent.h

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 // vim: ft=cpp tw=78 sw=2 et ts=2
 /* 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 "nsCOMPtr.h"
 #include "nsIImageLoadingContent.h"
 #include "nsIRequest.h"
 #include "mozilla/ErrorResult.h"
 #include "nsAutoPtr.h"
 class nsIURI;
 class nsIDocument;
 class imgILoader;
 class nsIIOService;
 class nsPresContext;
 class nsIContent;
 class imgRequestProxy;
 #ifdef LoadImage
 // Undefine LoadImage to prevent naming conflict with Windows.
 #undef LoadImage
 #endif
 class nsImageLoadingContent : public nsIImageLoadingContent,
                               public imgIOnloadBlocker
 {
   /* 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);
   already_AddRefed<nsIStreamListener>
     LoadImageWithChannel(nsIChannel* aChannel, mozilla::ErrorResult& aError);
   void ForceReload(mozilla::ErrorResult& aError);
 protected:
   /**
    * 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.
    */
   nsresult LoadImage(const nsAString& aNewURI, bool aForce,
                      bool aNotify);
   /**
    * 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 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,
                      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);
   /**
    * 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; }
   // Sets blocking state only if the desired state is different from the
   // current one. See the comment for mBlockingOnload for more information.
   void SetBlockingOnload(bool aBlocking);
   /**
    * 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(nsIDocument* aDocument, nsIContent* aParent,
                   nsIContent* aBindingParent, bool aCompileEventHandlers);
   void UnbindFromTree(bool aDeep, bool aNullParent);
   nsresult OnStopRequest(imgIRequest* aRequest, nsresult aStatus);
   void OnUnlockedDraw();
   nsresult OnImageIsAnimated(imgIRequest *aRequest);
 private:
   /**
    * Struct used to manage the image observers.
    */
   struct ImageObserver {
     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 "load" or "error" depending on how things went
    */
   nsresult FireEvent(const nsAString& aEventType);
 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.
    */
    nsRefPtr<imgRequestProxy>& PrepareNextRequest();
   /**
    * 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).
    */
   nsRefPtr<imgRequestProxy>& PrepareCurrentRequest();
   nsRefPtr<imgRequestProxy>& PreparePendingRequest();
   /**
    * 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.
    */
   void ClearCurrentRequest(nsresult aReason, uint32_t aFlags);
   void ClearPendingRequest(nsresult aReason, uint32_t aFlags);
   /**
    * 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.
    *
    * REQUEST_DISCARD passed to UntrackImage means we request the discard of the
    * decoded data of the image.
    */
   void TrackImage(imgIRequest* aImage);
   enum {
     REQUEST_DISCARD = 0x1
   };
   void UntrackImage(imgIRequest* aImage, uint32_t aFlags = 0);
   /* MEMBERS */
   nsRefPtr<imgRequestProxy> mCurrentRequest;
   nsRefPtr<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
   };
   // 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;
   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;
   bool mFireEventsOnDecode : 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;
   uint32_t mVisibleCount;
 };
 #endif // nsImageLoadingContent_h__

The Tor Browser / annotate

content/base/src/nsImageLoadingContent.h@6474c204b198 (annotated)

content/base/src/nsImageLoadingContent.h