The Tor Browser: content/base/src/nsImageLoadingContent.cpp@deefc01c0e14 (annotated)

content/base/src/nsImageLoadingContent.cpp@deefc01c0e14 (annotated)

content/base/src/nsImageLoadingContent.cpp

Thu, 15 Jan 2015 21:03:48 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 15 Jan 2015 21:03:48 +0100
branch: TOR_BUG_9701
changeset 11: deefc01c0e14
permissions: -rw-r--r--

Integrate friendly tips from Tor colleagues to make (or not) 4.5 alpha 3;
This includes removal of overloaded (but unused) methods, and addition of
a overlooked call to DataStruct::SetData(nsISupports, uint32_t, bool.)

 /* -*- 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).
  */
 #include "nsImageLoadingContent.h"
 #include "nsAutoPtr.h"
 #include "nsError.h"
 #include "nsIContent.h"
 #include "nsIDocument.h"
 #include "nsIScriptGlobalObject.h"
 #include "nsIDOMWindow.h"
 #include "nsServiceManagerUtils.h"
 #include "nsContentPolicyUtils.h"
 #include "nsIURI.h"
 #include "nsILoadGroup.h"
 #include "imgIContainer.h"
 #include "imgLoader.h"
 #include "imgRequestProxy.h"
 #include "nsThreadUtils.h"
 #include "nsNetUtil.h"
 #include "nsImageFrame.h"
 #include "nsIPresShell.h"
 #include "nsIChannel.h"
 #include "nsIStreamListener.h"
 #include "nsIFrame.h"
 #include "nsIDOMNode.h"
 #include "nsContentUtils.h"
 #include "nsLayoutUtils.h"
 #include "nsIContentPolicy.h"
 #include "nsSVGEffects.h"
 #include "mozAutoDocUpdate.h"
 #include "mozilla/AsyncEventDispatcher.h"
 #include "mozilla/EventStates.h"
 #include "mozilla/dom/Element.h"
 #include "mozilla/dom/ScriptSettings.h"
 #ifdef LoadImage
 // Undefine LoadImage to prevent naming conflict with Windows.
 #undef LoadImage
 #endif
 using namespace mozilla;
 #ifdef DEBUG_chb
 static void PrintReqURL(imgIRequest* req) {
   if (!req) {
     printf("(null req)\n");
     return;
   }
   nsCOMPtr<nsIURI> uri;
   req->GetURI(getter_AddRefs(uri));
   if (!uri) {
     printf("(null uri)\n");
     return;
   }
   nsAutoCString spec;
   uri->GetSpec(spec);
   printf("spec='%s'\n", spec.get());
 }
 #endif /* DEBUG_chb */
 nsImageLoadingContent::nsImageLoadingContent()
   : mCurrentRequestFlags(0),
     mPendingRequestFlags(0),
     mObserverList(nullptr),
     mImageBlockingStatus(nsIContentPolicy::ACCEPT),
     mLoadingEnabled(true),
     mIsImageStateForced(false),
     mLoading(false),
     // mBroken starts out true, since an image without a URI is broken....
     mBroken(true),
     mUserDisabled(false),
     mSuppressed(false),
     mFireEventsOnDecode(false),
     mNewRequestsWillNeedAnimationReset(false),
     mStateChangerDepth(0),
     mCurrentRequestRegistered(false),
     mPendingRequestRegistered(false),
     mFrameCreateCalled(false),
     mVisibleCount(0)
 {
   if (!nsContentUtils::GetImgLoaderForChannel(nullptr)) {
     mLoadingEnabled = false;
   }
 }
 void
 nsImageLoadingContent::DestroyImageLoadingContent()
 {
   // Cancel our requests so they won't hold stale refs to us
   // NB: Don't ask to discard the images here.
   ClearCurrentRequest(NS_BINDING_ABORTED, 0);
   ClearPendingRequest(NS_BINDING_ABORTED, 0);
 }
 nsImageLoadingContent::~nsImageLoadingContent()
 {
   NS_ASSERTION(!mCurrentRequest && !mPendingRequest,
                "DestroyImageLoadingContent not called");
   NS_ASSERTION(!mObserverList.mObserver && !mObserverList.mNext,
                "Observers still registered?");
 }
 /*
  * imgINotificationObserver impl
  */
 NS_IMETHODIMP
 nsImageLoadingContent::Notify(imgIRequest* aRequest,
                               int32_t aType,
                               const nsIntRect* aData)
 {
   if (aType == imgINotificationObserver::IS_ANIMATED) {
     return OnImageIsAnimated(aRequest);
   }
   if (aType == imgINotificationObserver::UNLOCKED_DRAW) {
     OnUnlockedDraw();
     return NS_OK;
   }
   if (aType == imgINotificationObserver::LOAD_COMPLETE) {
     // We should definitely have a request here
     NS_ABORT_IF_FALSE(aRequest, "no request?");
     NS_PRECONDITION(aRequest == mCurrentRequest || aRequest == mPendingRequest,
                     "Unknown request");
   }
   {
     nsAutoScriptBlocker scriptBlocker;
     for (ImageObserver* observer = &mObserverList, *next; observer;
          observer = next) {
       next = observer->mNext;
       if (observer->mObserver) {
         observer->mObserver->Notify(aRequest, aType, aData);
       }
     }
   }
   if (aType == imgINotificationObserver::SIZE_AVAILABLE) {
     // Have to check for state changes here, since we might have been in
     // the LOADING state before.
     UpdateImageState(true);
   }
   if (aType == imgINotificationObserver::LOAD_COMPLETE) {
     uint32_t reqStatus;
     aRequest->GetImageStatus(&reqStatus);
     nsresult status =
         reqStatus & imgIRequest::STATUS_ERROR ? NS_ERROR_FAILURE : NS_OK;
     return OnStopRequest(aRequest, status);
   }
   if (aType == imgINotificationObserver::DECODE_COMPLETE && mFireEventsOnDecode) {
     mFireEventsOnDecode = false;
     uint32_t reqStatus;
     aRequest->GetImageStatus(&reqStatus);
     if (reqStatus & imgIRequest::STATUS_ERROR) {
       FireEvent(NS_LITERAL_STRING("error"));
     } else {
       FireEvent(NS_LITERAL_STRING("load"));
     }
     UpdateImageState(true);
   }
   return NS_OK;
 }
 nsresult
 nsImageLoadingContent::OnStopRequest(imgIRequest* aRequest,
                                      nsresult aStatus)
 {
   uint32_t oldStatus;
   aRequest->GetImageStatus(&oldStatus);
   //XXXjdm This occurs when we have a pending request created, then another
   //       pending request replaces it before the first one is finished.
   //       This begs the question of what the correct behaviour is; we used
   //       to not have to care because we ran this code in OnStopDecode which
   //       wasn't called when the first request was cancelled. For now, I choose
   //       to punt when the given request doesn't appear to have terminated in
   //       an expected state.
   if (!(oldStatus & (imgIRequest::STATUS_ERROR | imgIRequest::STATUS_LOAD_COMPLETE)))
     return NS_OK;
   // Our state may change. Watch it.
   AutoStateChanger changer(this, true);
   // If the pending request is loaded, switch to it.
   if (aRequest == mPendingRequest) {
     MakePendingRequestCurrent();
   }
   NS_ABORT_IF_FALSE(aRequest == mCurrentRequest,
                     "One way or another, we should be current by now");
   // We just loaded all the data we're going to get. If we're visible and
   // haven't done an initial paint (*), we want to make sure the image starts
   // decoding immediately, for two reasons:
   //
   // 1) This image is sitting idle but might need to be decoded as soon as we
   // start painting, in which case we've wasted time.
   //
   // 2) We want to block onload until all visible images are decoded. We do this
   // by blocking onload until all in-progress decodes get at least one frame
   // decoded. However, if all the data comes in while painting is suppressed
   // (ie, before the initial paint delay is finished), we fire onload without
   // doing a paint first. This means that decode-on-draw images don't start
   // decoding, so we can't wait for them to finish. See bug 512435.
   //
   // (*) IsPaintingSuppressed returns false if we haven't gotten the initial
   // reflow yet, so we have to test !DidInitialize || IsPaintingSuppressed.
   // It's possible for painting to be suppressed for reasons other than the
   // initial paint delay (for example, being in the bfcache), but we probably
   // aren't loading images in those situations.
   // XXXkhuey should this be GetOurCurrentDoc?  Decoding if we're not in
   // the document seems silly.
   bool startedDecoding = false;
   nsIDocument* doc = GetOurOwnerDoc();
   nsIPresShell* shell = doc ? doc->GetShell() : nullptr;
   if (shell && shell->IsVisible() &&
       (!shell->DidInitialize() || shell->IsPaintingSuppressed())) {
     // If we've gotten a frame and that frame has called FrameCreate and that
     // frame has been reflowed then we know that it checked it's own visibility
     // so we can trust our visible count and we don't start decode if we are not
     // visible.
     nsIFrame* f = GetOurPrimaryFrame();
     if (!mFrameCreateCalled || !f || (f->GetStateBits() & NS_FRAME_FIRST_REFLOW) ||
         mVisibleCount > 0 || shell->AssumeAllImagesVisible()) {
       if (NS_SUCCEEDED(mCurrentRequest->StartDecoding())) {
         startedDecoding = true;
       }
     }
   }
   // We want to give the decoder a chance to find errors. If we haven't found
   // an error yet and we've started decoding, either from the above
   // StartDecoding or from some other place, we must only fire these events
   // after we finish decoding.
   uint32_t reqStatus;
   aRequest->GetImageStatus(&reqStatus);
   if (NS_SUCCEEDED(aStatus) && !(reqStatus & imgIRequest::STATUS_ERROR) &&
       (reqStatus & imgIRequest::STATUS_DECODE_STARTED ||
        (startedDecoding && !(reqStatus & imgIRequest::STATUS_DECODE_COMPLETE)))) {
     mFireEventsOnDecode = true;
   } else {
     // Fire the appropriate DOM event.
     if (NS_SUCCEEDED(aStatus)) {
       FireEvent(NS_LITERAL_STRING("load"));
     } else {
       FireEvent(NS_LITERAL_STRING("error"));
     }
   }
   nsCOMPtr<nsINode> thisNode = do_QueryInterface(static_cast<nsIImageLoadingContent*>(this));
   nsSVGEffects::InvalidateDirectRenderingObservers(thisNode->AsElement());
   return NS_OK;
 }
 void
 nsImageLoadingContent::OnUnlockedDraw()
 {
   if (mVisibleCount > 0) {
     // We should already be marked as visible, there is nothing more we can do.
     return;
   }
   nsPresContext* presContext = GetFramePresContext();
   if (!presContext)
     return;
   nsIPresShell* presShell = presContext->PresShell();
   if (!presShell)
     return;
   presShell->EnsureImageInVisibleList(this);
 }
 nsresult
 nsImageLoadingContent::OnImageIsAnimated(imgIRequest *aRequest)
 {
   bool* requestFlag = GetRegisteredFlagForRequest(aRequest);
   if (requestFlag) {
     nsLayoutUtils::RegisterImageRequest(GetFramePresContext(),
                                         aRequest, requestFlag);
   }
   return NS_OK;
 }
 /*
  * nsIImageLoadingContent impl
  */
 NS_IMETHODIMP
 nsImageLoadingContent::GetLoadingEnabled(bool *aLoadingEnabled)
 {
   *aLoadingEnabled = mLoadingEnabled;
   return NS_OK;
 }
 NS_IMETHODIMP
 nsImageLoadingContent::SetLoadingEnabled(bool aLoadingEnabled)
 {
   if (nsContentUtils::GetImgLoaderForChannel(nullptr)) {
     mLoadingEnabled = aLoadingEnabled;
   }
   return NS_OK;
 }
 NS_IMETHODIMP
 nsImageLoadingContent::GetImageBlockingStatus(int16_t* aStatus)
 {
   NS_PRECONDITION(aStatus, "Null out param");
   *aStatus = ImageBlockingStatus();
   return NS_OK;
 }
 NS_IMETHODIMP
 nsImageLoadingContent::AddObserver(imgINotificationObserver* aObserver)
 {
   NS_ENSURE_ARG_POINTER(aObserver);
   if (!mObserverList.mObserver) {
     mObserverList.mObserver = aObserver;
     // Don't touch the linking of the list!
     return NS_OK;
   }
   // otherwise we have to create a new entry
   ImageObserver* observer = &mObserverList;
   while (observer->mNext) {
     observer = observer->mNext;
   }
   observer->mNext = new ImageObserver(aObserver);
   if (! observer->mNext) {
     return NS_ERROR_OUT_OF_MEMORY;
   }
   return NS_OK;
 }
 NS_IMETHODIMP
 nsImageLoadingContent::RemoveObserver(imgINotificationObserver* aObserver)
 {
   NS_ENSURE_ARG_POINTER(aObserver);
   if (mObserverList.mObserver == aObserver) {
     mObserverList.mObserver = nullptr;
     // Don't touch the linking of the list!
     return NS_OK;
   }
   // otherwise have to find it and splice it out
   ImageObserver* observer = &mObserverList;
   while (observer->mNext && observer->mNext->mObserver != aObserver) {
     observer = observer->mNext;
   }
   // At this point, we are pointing to the list element whose mNext is
   // the right observer (assuming of course that mNext is not null)
   if (observer->mNext) {
     // splice it out
     ImageObserver* oldObserver = observer->mNext;
     observer->mNext = oldObserver->mNext;
     oldObserver->mNext = nullptr;  // so we don't destroy them all
     delete oldObserver;
   }
 #ifdef DEBUG
   else {
     NS_WARNING("Asked to remove nonexistent observer");
   }
 #endif
   return NS_OK;
 }
 already_AddRefed<imgIRequest>
 nsImageLoadingContent::GetRequest(int32_t aRequestType,
                                   ErrorResult& aError)
 {
   nsCOMPtr<imgIRequest> request;
   switch(aRequestType) {
   case CURRENT_REQUEST:
     request = mCurrentRequest;
     break;
   case PENDING_REQUEST:
     request = mPendingRequest;
     break;
   default:
     NS_ERROR("Unknown request type");
     aError.Throw(NS_ERROR_UNEXPECTED);
   }
   return request.forget();
 }
 NS_IMETHODIMP
 nsImageLoadingContent::GetRequest(int32_t aRequestType,
                                   imgIRequest** aRequest)
 {
   NS_ENSURE_ARG_POINTER(aRequest);
   ErrorResult result;
   *aRequest = GetRequest(aRequestType, result).take();
   return result.ErrorCode();
 }
 NS_IMETHODIMP_(void)
 nsImageLoadingContent::FrameCreated(nsIFrame* aFrame)
 {
   NS_ASSERTION(aFrame, "aFrame is null");
   mFrameCreateCalled = true;
   if (aFrame->HasAnyStateBits(NS_FRAME_IN_POPUP)) {
     // Assume all images in popups are visible.
     IncrementVisibleCount();
   }
   TrackImage(mCurrentRequest);
   TrackImage(mPendingRequest);
   // We need to make sure that our image request is registered, if it should
   // be registered.
   nsPresContext* presContext = aFrame->PresContext();
   if (mCurrentRequest) {
     nsLayoutUtils::RegisterImageRequestIfAnimated(presContext, mCurrentRequest,
                                                   &mCurrentRequestRegistered);
   }
   if (mPendingRequest) {
     nsLayoutUtils::RegisterImageRequestIfAnimated(presContext, mPendingRequest,
                                                   &mPendingRequestRegistered);
   }
 }
 NS_IMETHODIMP_(void)
 nsImageLoadingContent::FrameDestroyed(nsIFrame* aFrame)
 {
   NS_ASSERTION(aFrame, "aFrame is null");
   mFrameCreateCalled = false;
   // We need to make sure that our image request is deregistered.
   nsPresContext* presContext = GetFramePresContext();
   if (mCurrentRequest) {
     nsLayoutUtils::DeregisterImageRequest(presContext,
                                           mCurrentRequest,
                                           &mCurrentRequestRegistered);
   }
   if (mPendingRequest) {
     nsLayoutUtils::DeregisterImageRequest(presContext,
                                           mPendingRequest,
                                           &mPendingRequestRegistered);
   }
   UntrackImage(mCurrentRequest);
   UntrackImage(mPendingRequest);
   nsIPresShell* presShell = presContext ? presContext->GetPresShell() : nullptr;
   if (presShell) {
     presShell->RemoveImageFromVisibleList(this);
   }
   if (aFrame->HasAnyStateBits(NS_FRAME_IN_POPUP)) {
     // We assume all images in popups are visible, so this decrement balances
     // out the increment in FrameCreated above.
     DecrementVisibleCount();
   }
 }
 int32_t
 nsImageLoadingContent::GetRequestType(imgIRequest* aRequest,
                                       ErrorResult& aError)
 {
   if (aRequest == mCurrentRequest) {
     return CURRENT_REQUEST;
   }
   if (aRequest == mPendingRequest) {
     return PENDING_REQUEST;
   }
   NS_ERROR("Unknown request");
   aError.Throw(NS_ERROR_UNEXPECTED);
   return UNKNOWN_REQUEST;
 }
 NS_IMETHODIMP
 nsImageLoadingContent::GetRequestType(imgIRequest* aRequest,
                                       int32_t* aRequestType)
 {
   NS_PRECONDITION(aRequestType, "Null out param");
   ErrorResult result;
   *aRequestType = GetRequestType(aRequest, result);
   return result.ErrorCode();
 }
 already_AddRefed<nsIURI>
 nsImageLoadingContent::GetCurrentURI(ErrorResult& aError)
 {
   nsCOMPtr<nsIURI> uri;
   if (mCurrentRequest) {
     mCurrentRequest->GetURI(getter_AddRefs(uri));
   } else if (mCurrentURI) {
     nsresult rv = NS_EnsureSafeToReturn(mCurrentURI, getter_AddRefs(uri));
     if (NS_FAILED(rv)) {
       aError.Throw(rv);
     }
   }
   return uri.forget();
 }
 NS_IMETHODIMP
 nsImageLoadingContent::GetCurrentURI(nsIURI** aURI)
 {
   NS_ENSURE_ARG_POINTER(aURI);
   ErrorResult result;
   *aURI = GetCurrentURI(result).take();
   return result.ErrorCode();
 }
 already_AddRefed<nsIStreamListener>
 nsImageLoadingContent::LoadImageWithChannel(nsIChannel* aChannel,
                                             ErrorResult& aError)
 {
   if (!nsContentUtils::GetImgLoaderForChannel(aChannel)) {
     aError.Throw(NS_ERROR_NULL_POINTER);
     return nullptr;
   }
   nsCOMPtr<nsIDocument> doc = GetOurOwnerDoc();
   if (!doc) {
     // Don't bother
     return nullptr;
   }
   // XXX what should we do with content policies here, if anything?
   // Shouldn't that be done before the start of the load?
   // XXX what about shouldProcess?
   // Our state might change. Watch it.
   AutoStateChanger changer(this, true);
   // Do the load.
   nsCOMPtr<nsIStreamListener> listener;
   nsRefPtr<imgRequestProxy>& req = PrepareNextRequest();
   nsresult rv = nsContentUtils::GetImgLoaderForChannel(aChannel)->
     LoadImageWithChannel(aChannel, this, doc,
                          getter_AddRefs(listener),
                          getter_AddRefs(req));
   if (NS_SUCCEEDED(rv)) {
     TrackImage(req);
     ResetAnimationIfNeeded();
   } else {
     MOZ_ASSERT(!req, "Shouldn't have non-null request here");
     // If we don't have a current URI, we might as well store this URI so people
     // know what we tried (and failed) to load.
     if (!mCurrentRequest)
       aChannel->GetURI(getter_AddRefs(mCurrentURI));
     FireEvent(NS_LITERAL_STRING("error"));
     aError.Throw(rv);
   }
   return listener.forget();
 }
 NS_IMETHODIMP
 nsImageLoadingContent::LoadImageWithChannel(nsIChannel* aChannel,
                                             nsIStreamListener** aListener)
 {
   NS_ENSURE_ARG_POINTER(aListener);
   ErrorResult result;
   *aListener = LoadImageWithChannel(aChannel, result).take();
   return result.ErrorCode();
 }
 void
 nsImageLoadingContent::ForceReload(ErrorResult& aError)
 {
   nsCOMPtr<nsIURI> currentURI;
   GetCurrentURI(getter_AddRefs(currentURI));
   if (!currentURI) {
     aError.Throw(NS_ERROR_NOT_AVAILABLE);
     return;
   }
   nsresult rv = LoadImage(currentURI, true, true, nullptr, nsIRequest::VALIDATE_ALWAYS);
   if (NS_FAILED(rv)) {
     aError.Throw(rv);
   }
 }
 NS_IMETHODIMP nsImageLoadingContent::ForceReload()
 {
   ErrorResult result;
   ForceReload(result);
   return result.ErrorCode();
 }
 NS_IMETHODIMP
 nsImageLoadingContent::BlockOnload(imgIRequest* aRequest)
 {
   if (aRequest == mCurrentRequest) {
     NS_ASSERTION(!(mCurrentRequestFlags & REQUEST_BLOCKS_ONLOAD),
                  "Double BlockOnload!?");
     mCurrentRequestFlags |= REQUEST_BLOCKS_ONLOAD;
   } else if (aRequest == mPendingRequest) {
     NS_ASSERTION(!(mPendingRequestFlags & REQUEST_BLOCKS_ONLOAD),
                  "Double BlockOnload!?");
     mPendingRequestFlags |= REQUEST_BLOCKS_ONLOAD;
   } else {
     return NS_OK;
   }
   nsIDocument* doc = GetOurCurrentDoc();
   if (doc) {
     doc->BlockOnload();
   }
   return NS_OK;
 }
 NS_IMETHODIMP
 nsImageLoadingContent::UnblockOnload(imgIRequest* aRequest)
 {
   if (aRequest == mCurrentRequest) {
     NS_ASSERTION(mCurrentRequestFlags & REQUEST_BLOCKS_ONLOAD,
                  "Double UnblockOnload!?");
     mCurrentRequestFlags &= ~REQUEST_BLOCKS_ONLOAD;
   } else if (aRequest == mPendingRequest) {
     NS_ASSERTION(mPendingRequestFlags & REQUEST_BLOCKS_ONLOAD,
                  "Double UnblockOnload!?");
     mPendingRequestFlags &= ~REQUEST_BLOCKS_ONLOAD;
   } else {
     return NS_OK;
   }
   nsIDocument* doc = GetOurCurrentDoc();
   if (doc) {
     doc->UnblockOnload(false);
   }
   return NS_OK;
 }
 void
 nsImageLoadingContent::IncrementVisibleCount()
 {
   mVisibleCount++;
   if (mVisibleCount == 1) {
     TrackImage(mCurrentRequest);
     TrackImage(mPendingRequest);
   }
 }
 void
 nsImageLoadingContent::DecrementVisibleCount()
 {
   NS_ASSERTION(mVisibleCount > 0, "visible count should be positive here");
   mVisibleCount--;
   if (mVisibleCount == 0) {
     UntrackImage(mCurrentRequest);
     UntrackImage(mPendingRequest);
   }
 }
 uint32_t
 nsImageLoadingContent::GetVisibleCount()
 {
   return mVisibleCount;
 }
 /*
  * Non-interface methods
  */
 nsresult
 nsImageLoadingContent::LoadImage(const nsAString& aNewURI,
                                  bool aForce,
                                  bool aNotify)
 {
   // First, get a document (needed for security checks and the like)
   nsIDocument* doc = GetOurOwnerDoc();
   if (!doc) {
     // No reason to bother, I think...
     return NS_OK;
   }
   nsCOMPtr<nsIURI> imageURI;
   nsresult rv = StringToURI(aNewURI, doc, getter_AddRefs(imageURI));
   NS_ENSURE_SUCCESS(rv, rv);
   // XXXbiesi fire onerror if that failed?
   bool equal;
   if (aNewURI.IsEmpty() &&
       doc->GetDocumentURI() &&
       NS_SUCCEEDED(doc->GetDocumentURI()->EqualsExceptRef(imageURI, &equal)) &&
       equal)  {
     // Loading an embedded img from the same URI as the document URI will not work
     // as a resource cannot recursively embed itself. Attempting to do so generally
     // results in having to pre-emptively close down an in-flight HTTP transaction
     // and then incurring the significant cost of establishing a new TCP channel.
     // This is generally triggered from <img src="">
     // In light of that, just skip loading it..
     // Do make sure to drop our existing image, if any
     CancelImageRequests(aNotify);
     return NS_OK;
   }
   NS_TryToSetImmutable(imageURI);
   return LoadImage(imageURI, aForce, aNotify, doc);
 }
 nsresult
 nsImageLoadingContent::LoadImage(nsIURI* aNewURI,
                                  bool aForce,
                                  bool aNotify,
                                  nsIDocument* aDocument,
                                  nsLoadFlags aLoadFlags)
 {
   if (!mLoadingEnabled) {
     // XXX Why fire an error here? seems like the callers to SetLoadingEnabled
     // don't want/need it.
     FireEvent(NS_LITERAL_STRING("error"));
     return NS_OK;
   }
   NS_ASSERTION(!aDocument || aDocument == GetOurOwnerDoc(),
                "Bogus document passed in");
   // First, get a document (needed for security checks and the like)
   if (!aDocument) {
     aDocument = GetOurOwnerDoc();
     if (!aDocument) {
       // No reason to bother, I think...
       return NS_OK;
     }
   }
   // URI equality check.
   //
   // We skip the equality check if our current image was blocked, since in that
   // case we really do want to try loading again.
   if (!aForce && NS_CP_ACCEPTED(mImageBlockingStatus)) {
     nsCOMPtr<nsIURI> currentURI;
     GetCurrentURI(getter_AddRefs(currentURI));
     bool equal;
     if (currentURI &&
         NS_SUCCEEDED(currentURI->Equals(aNewURI, &equal)) &&
         equal) {
       // Nothing to do here.
       return NS_OK;
     }
   }
   // From this point on, our image state could change. Watch it.
   AutoStateChanger changer(this, aNotify);
   // Sanity check.
   //
   // We use the principal of aDocument to avoid having to QI |this| an extra
   // time. It should always be the same as the principal of this node.
 #ifdef DEBUG
   nsCOMPtr<nsIContent> thisContent = do_QueryInterface(static_cast<nsIImageLoadingContent*>(this));
   NS_ABORT_IF_FALSE(thisContent &&
                     thisContent->NodePrincipal() == aDocument->NodePrincipal(),
                     "Principal mismatch?");
 #endif
   // Are we blocked?
   int16_t cpDecision = nsIContentPolicy::REJECT_REQUEST;
   nsContentUtils::CanLoadImage(aNewURI,
                                static_cast<nsIImageLoadingContent*>(this),
                                aDocument,
                                aDocument->NodePrincipal(),
                                &cpDecision);
   if (!NS_CP_ACCEPTED(cpDecision)) {
     FireEvent(NS_LITERAL_STRING("error"));
     SetBlockedRequest(aNewURI, cpDecision);
     return NS_OK;
   }
   nsLoadFlags loadFlags = aLoadFlags;
   int32_t corsmode = GetCORSMode();
   if (corsmode == CORS_ANONYMOUS) {
     loadFlags |= imgILoader::LOAD_CORS_ANONYMOUS;
   } else if (corsmode == CORS_USE_CREDENTIALS) {
     loadFlags |= imgILoader::LOAD_CORS_USE_CREDENTIALS;
   }
   // Not blocked. Do the load.
   nsRefPtr<imgRequestProxy>& req = PrepareNextRequest();
   nsCOMPtr<nsIContent> content =
       do_QueryInterface(static_cast<nsIImageLoadingContent*>(this));
   nsresult rv;
   rv = nsContentUtils::LoadImage(aNewURI, aDocument,
                                  aDocument->NodePrincipal(),
                                  aDocument->GetDocumentURI(),
                                  this, loadFlags,
                                  content->LocalName(),
                                  getter_AddRefs(req));
   if (NS_SUCCEEDED(rv)) {
     TrackImage(req);
     ResetAnimationIfNeeded();
     // Handle cases when we just ended up with a pending request but it's
     // already done.  In that situation we have to synchronously switch that
     // request to being the current request, because websites depend on that
     // behavior.
     if (req == mPendingRequest) {
       uint32_t pendingLoadStatus;
       rv = req->GetImageStatus(&pendingLoadStatus);
       if (NS_SUCCEEDED(rv) &&
           (pendingLoadStatus & imgIRequest::STATUS_LOAD_COMPLETE)) {
         MakePendingRequestCurrent();
         MOZ_ASSERT(mCurrentRequest,
                    "How could we not have a current request here?");
         nsImageFrame *f = do_QueryFrame(GetOurPrimaryFrame());
         if (f) {
           f->NotifyNewCurrentRequest(mCurrentRequest, NS_OK);
         }
       }
     }
   } else {
     MOZ_ASSERT(!req, "Shouldn't have non-null request here");
     // If we don't have a current URI, we might as well store this URI so people
     // know what we tried (and failed) to load.
     if (!mCurrentRequest)
       mCurrentURI = aNewURI;
     FireEvent(NS_LITERAL_STRING("error"));
     return NS_OK;
   }
   return NS_OK;
 }
 nsresult
 nsImageLoadingContent::ForceImageState(bool aForce,
                                        EventStates::InternalType aState)
 {
   mIsImageStateForced = aForce;
   mForcedImageState = EventStates(aState);
   return NS_OK;
 }
 EventStates
 nsImageLoadingContent::ImageState() const
 {
   if (mIsImageStateForced) {
     return mForcedImageState;
   }
   EventStates states;
   if (mBroken) {
     states |= NS_EVENT_STATE_BROKEN;
   }
   if (mUserDisabled) {
     states |= NS_EVENT_STATE_USERDISABLED;
   }
   if (mSuppressed) {
     states |= NS_EVENT_STATE_SUPPRESSED;
   }
   if (mLoading) {
     states |= NS_EVENT_STATE_LOADING;
   }
   return states;
 }
 void
 nsImageLoadingContent::UpdateImageState(bool aNotify)
 {
   if (mStateChangerDepth > 0) {
     // Ignore this call; we'll update our state when the outermost state
     // changer is destroyed. Need this to work around the fact that some libpr0n
     // stuff is actually sync and hence we can get OnStopDecode called while
     // we're still under LoadImage, and OnStopDecode doesn't know anything about
     // aNotify.
     // XXX - This machinery should be removed after bug 521604.
     return;
   }
   nsCOMPtr<nsIContent> thisContent = do_QueryInterface(static_cast<nsIImageLoadingContent*>(this));
   if (!thisContent) {
     return;
   }
   mLoading = mBroken = mUserDisabled = mSuppressed = false;
   // If we were blocked by server-based content policy, we claim to be
   // suppressed.  If we were blocked by type-based content policy, we claim to
   // be user-disabled.  Otherwise, claim to be broken.
   if (mImageBlockingStatus == nsIContentPolicy::REJECT_SERVER) {
     mSuppressed = true;
   } else if (mImageBlockingStatus == nsIContentPolicy::REJECT_TYPE) {
     mUserDisabled = true;
   } else if (!mCurrentRequest) {
     // No current request means error, since we weren't disabled or suppressed
     mBroken = true;
   } else {
     uint32_t currentLoadStatus;
     nsresult rv = mCurrentRequest->GetImageStatus(&currentLoadStatus);
     if (NS_FAILED(rv) || (currentLoadStatus & imgIRequest::STATUS_ERROR)) {
       mBroken = true;
     } else if (!(currentLoadStatus & imgIRequest::STATUS_SIZE_AVAILABLE)) {
       mLoading = true;
     }
   }
   NS_ASSERTION(thisContent->IsElement(), "Not an element?");
   thisContent->AsElement()->UpdateState(aNotify);
 }
 void
 nsImageLoadingContent::CancelImageRequests(bool aNotify)
 {
   AutoStateChanger changer(this, aNotify);
   ClearPendingRequest(NS_BINDING_ABORTED, REQUEST_DISCARD);
   ClearCurrentRequest(NS_BINDING_ABORTED, REQUEST_DISCARD);
 }
 nsresult
 nsImageLoadingContent::UseAsPrimaryRequest(imgRequestProxy* aRequest,
                                            bool aNotify)
 {
   // Our state will change. Watch it.
   AutoStateChanger changer(this, aNotify);
   // Get rid if our existing images
   ClearPendingRequest(NS_BINDING_ABORTED, REQUEST_DISCARD);
   ClearCurrentRequest(NS_BINDING_ABORTED, REQUEST_DISCARD);
   // Clone the request we were given.
   nsRefPtr<imgRequestProxy>& req = PrepareNextRequest();
   nsresult rv = aRequest->Clone(this, getter_AddRefs(req));
   if (NS_SUCCEEDED(rv)) {
     TrackImage(req);
   } else {
     MOZ_ASSERT(!req, "Shouldn't have non-null request here");
     return rv;
   }
   return NS_OK;
 }
 nsIDocument*
 nsImageLoadingContent::GetOurOwnerDoc()
 {
   nsCOMPtr<nsIContent> thisContent =
     do_QueryInterface(static_cast<nsIImageLoadingContent*>(this));
   NS_ENSURE_TRUE(thisContent, nullptr);
   return thisContent->OwnerDoc();
 }
 nsIDocument*
 nsImageLoadingContent::GetOurCurrentDoc()
 {
   nsCOMPtr<nsIContent> thisContent =
     do_QueryInterface(static_cast<nsIImageLoadingContent*>(this));
   NS_ENSURE_TRUE(thisContent, nullptr);
   return thisContent->GetCurrentDoc();
 }
 nsIFrame*
 nsImageLoadingContent::GetOurPrimaryFrame()
 {
   nsCOMPtr<nsIContent> thisContent =
     do_QueryInterface(static_cast<nsIImageLoadingContent*>(this));
   return thisContent->GetPrimaryFrame();
 }
 nsPresContext* nsImageLoadingContent::GetFramePresContext()
 {
   nsIFrame* frame = GetOurPrimaryFrame();
   if (!frame) {
     return nullptr;
   }
   return frame->PresContext();
 }
 nsresult
 nsImageLoadingContent::StringToURI(const nsAString& aSpec,
                                    nsIDocument* aDocument,
                                    nsIURI** aURI)
 {
   NS_PRECONDITION(aDocument, "Must have a document");
   NS_PRECONDITION(aURI, "Null out param");
   // (1) Get the base URI
   nsCOMPtr<nsIContent> thisContent = do_QueryInterface(static_cast<nsIImageLoadingContent*>(this));
   NS_ASSERTION(thisContent, "An image loading content must be an nsIContent");
   nsCOMPtr<nsIURI> baseURL = thisContent->GetBaseURI();
   // (2) Get the charset
   const nsAFlatCString &charset = aDocument->GetDocumentCharacterSet();
   // (3) Construct the silly thing
   return NS_NewURI(aURI,
                    aSpec,
                    charset.IsEmpty() ? nullptr : charset.get(),
                    baseURL,
                    nsContentUtils::GetIOService());
 }
 nsresult
 nsImageLoadingContent::FireEvent(const nsAString& aEventType)
 {
   // We have to fire the event asynchronously so that we won't go into infinite
   // loops in cases when onLoad handlers reset the src and the new src is in
   // cache.
   nsCOMPtr<nsINode> thisNode = do_QueryInterface(static_cast<nsIImageLoadingContent*>(this));
   nsRefPtr<AsyncEventDispatcher> loadBlockingAsyncDispatcher =
     new LoadBlockingAsyncEventDispatcher(thisNode, aEventType, false, false);
   loadBlockingAsyncDispatcher->PostDOMEvent();
   return NS_OK;
 }
 nsRefPtr<imgRequestProxy>&
 nsImageLoadingContent::PrepareNextRequest()
 {
   // If we don't have a usable current request, get rid of any half-baked
   // request that might be sitting there and make this one current.
   if (!HaveSize(mCurrentRequest))
     return PrepareCurrentRequest();
   // Otherwise, make it pending.
   return PreparePendingRequest();
 }
 void
 nsImageLoadingContent::SetBlockedRequest(nsIURI* aURI, int16_t aContentDecision)
 {
   // Sanity
   NS_ABORT_IF_FALSE(!NS_CP_ACCEPTED(aContentDecision), "Blocked but not?");
   // We do some slightly illogical stuff here to maintain consistency with
   // old behavior that people probably depend on. Even in the case where the
   // new image is blocked, the old one should really be canceled with the
   // reason "image source changed". However, apparently there's some abuse
   // over in nsImageFrame where the displaying of the "broken" icon for the
   // next image depends on the cancel reason of the previous image. ugh.
   ClearPendingRequest(NS_ERROR_IMAGE_BLOCKED, REQUEST_DISCARD);
   // For the blocked case, we only want to cancel the existing current request
   // if size is not available. bz says the web depends on this behavior.
   if (!HaveSize(mCurrentRequest)) {
     mImageBlockingStatus = aContentDecision;
     ClearCurrentRequest(NS_ERROR_IMAGE_BLOCKED, REQUEST_DISCARD);
     // We still want to remember what URI we were despite not having an actual
     // request.
     mCurrentURI = aURI;
   }
 }
 nsRefPtr<imgRequestProxy>&
 nsImageLoadingContent::PrepareCurrentRequest()
 {
   // Blocked images go through SetBlockedRequest, which is a separate path. For
   // everything else, we're unblocked.
   mImageBlockingStatus = nsIContentPolicy::ACCEPT;
   // Get rid of anything that was there previously.
   ClearCurrentRequest(NS_ERROR_IMAGE_SRC_CHANGED, REQUEST_DISCARD);
   if (mNewRequestsWillNeedAnimationReset) {
     mCurrentRequestFlags |= REQUEST_NEEDS_ANIMATION_RESET;
   }
   // Return a reference.
   return mCurrentRequest;
 }
 nsRefPtr<imgRequestProxy>&
 nsImageLoadingContent::PreparePendingRequest()
 {
   // Get rid of anything that was there previously.
   ClearPendingRequest(NS_ERROR_IMAGE_SRC_CHANGED, REQUEST_DISCARD);
   if (mNewRequestsWillNeedAnimationReset) {
     mPendingRequestFlags |= REQUEST_NEEDS_ANIMATION_RESET;
   }
   // Return a reference.
   return mPendingRequest;
 }
 namespace {
 class ImageRequestAutoLock
 {
 public:
   ImageRequestAutoLock(imgIRequest* aRequest)
     : mRequest(aRequest)
   {
     if (mRequest) {
       mRequest->LockImage();
     }
   }
   ~ImageRequestAutoLock()
   {
     if (mRequest) {
       mRequest->UnlockImage();
     }
   }
 private:
   nsCOMPtr<imgIRequest> mRequest;
 };
 } // anonymous namespace
 void
 nsImageLoadingContent::MakePendingRequestCurrent()
 {
   MOZ_ASSERT(mPendingRequest);
   // Lock mCurrentRequest for the duration of this method.  We do this because
   // PrepareCurrentRequest() might unlock mCurrentRequest.  If mCurrentRequest
   // and mPendingRequest are both requests for the same image, unlocking
   // mCurrentRequest before we lock mPendingRequest can cause the lock count
   // to go to 0 and the image to be discarded!
   ImageRequestAutoLock autoLock(mCurrentRequest);
   PrepareCurrentRequest() = mPendingRequest;
   mPendingRequest = nullptr;
   mCurrentRequestFlags = mPendingRequestFlags;
   mPendingRequestFlags = 0;
   ResetAnimationIfNeeded();
 }
 void
 nsImageLoadingContent::ClearCurrentRequest(nsresult aReason,
                                            uint32_t aFlags)
 {
   if (!mCurrentRequest) {
     // Even if we didn't have a current request, we might have been keeping
     // a URI as a placeholder for a failed load. Clear that now.
     mCurrentURI = nullptr;
     return;
   }
   NS_ABORT_IF_FALSE(!mCurrentURI,
                     "Shouldn't have both mCurrentRequest and mCurrentURI!");
   // Deregister this image from the refresh driver so it no longer receives
   // notifications.
   nsLayoutUtils::DeregisterImageRequest(GetFramePresContext(), mCurrentRequest,
                                         &mCurrentRequestRegistered);
   // Clean up the request.
   UntrackImage(mCurrentRequest, aFlags);
   mCurrentRequest->CancelAndForgetObserver(aReason);
   mCurrentRequest = nullptr;
   mCurrentRequestFlags = 0;
 }
 void
 nsImageLoadingContent::ClearPendingRequest(nsresult aReason,
                                            uint32_t aFlags)
 {
   if (!mPendingRequest)
     return;
   // Deregister this image from the refresh driver so it no longer receives
   // notifications.
   nsLayoutUtils::DeregisterImageRequest(GetFramePresContext(), mPendingRequest,
                                         &mPendingRequestRegistered);
   UntrackImage(mPendingRequest, aFlags);
   mPendingRequest->CancelAndForgetObserver(aReason);
   mPendingRequest = nullptr;
   mPendingRequestFlags = 0;
 }
 bool*
 nsImageLoadingContent::GetRegisteredFlagForRequest(imgIRequest* aRequest)
 {
   if (aRequest == mCurrentRequest) {
     return &mCurrentRequestRegistered;
   } else if (aRequest == mPendingRequest) {
     return &mPendingRequestRegistered;
   } else {
     return nullptr;
   }
 }
 void
 nsImageLoadingContent::ResetAnimationIfNeeded()
 {
   if (mCurrentRequest &&
       (mCurrentRequestFlags & REQUEST_NEEDS_ANIMATION_RESET)) {
     nsCOMPtr<imgIContainer> container;
     mCurrentRequest->GetImage(getter_AddRefs(container));
     if (container)
       container->ResetAnimation();
     mCurrentRequestFlags &= ~REQUEST_NEEDS_ANIMATION_RESET;
   }
 }
 bool
 nsImageLoadingContent::HaveSize(imgIRequest *aImage)
 {
   // Handle the null case
   if (!aImage)
     return false;
   // Query the image
   uint32_t status;
   nsresult rv = aImage->GetImageStatus(&status);
   return (NS_SUCCEEDED(rv) && (status & imgIRequest::STATUS_SIZE_AVAILABLE));
 }
 void
 nsImageLoadingContent::BindToTree(nsIDocument* aDocument, nsIContent* aParent,
                                   nsIContent* aBindingParent,
                                   bool aCompileEventHandlers)
 {
   // We may be entering the document, so if our image should be tracked,
   // track it.
   if (!aDocument)
     return;
   TrackImage(mCurrentRequest);
   TrackImage(mPendingRequest);
   if (mCurrentRequestFlags & REQUEST_BLOCKS_ONLOAD)
     aDocument->BlockOnload();
 }
 void
 nsImageLoadingContent::UnbindFromTree(bool aDeep, bool aNullParent)
 {
   // We may be leaving the document, so if our image is tracked, untrack it.
   nsCOMPtr<nsIDocument> doc = GetOurCurrentDoc();
   if (!doc)
     return;
   UntrackImage(mCurrentRequest);
   UntrackImage(mPendingRequest);
   if (mCurrentRequestFlags & REQUEST_BLOCKS_ONLOAD)
     doc->UnblockOnload(false);
 }
 void
 nsImageLoadingContent::TrackImage(imgIRequest* aImage)
 {
   if (!aImage)
     return;
   MOZ_ASSERT(aImage == mCurrentRequest || aImage == mPendingRequest,
              "Why haven't we heard of this request?");
   nsIDocument* doc = GetOurCurrentDoc();
   if (doc && (mFrameCreateCalled || GetOurPrimaryFrame()) &&
       (mVisibleCount > 0)) {
     if (aImage == mCurrentRequest && !(mCurrentRequestFlags & REQUEST_IS_TRACKED)) {
       mCurrentRequestFlags |= REQUEST_IS_TRACKED;
       doc->AddImage(mCurrentRequest);
     }
     if (aImage == mPendingRequest && !(mPendingRequestFlags & REQUEST_IS_TRACKED)) {
       mPendingRequestFlags |= REQUEST_IS_TRACKED;
       doc->AddImage(mPendingRequest);
     }
   }
 }
 void
 nsImageLoadingContent::UntrackImage(imgIRequest* aImage, uint32_t aFlags /* = 0 */)
 {
   if (!aImage)
     return;
   MOZ_ASSERT(aImage == mCurrentRequest || aImage == mPendingRequest,
              "Why haven't we heard of this request?");
   // We may not be in the document.  If we outlived our document that's fine,
   // because the document empties out the tracker and unlocks all locked images
   // on destruction.  But if we were never in the document we may need to force
   // discarding the image here, since this is the only chance we have.
   nsIDocument* doc = GetOurCurrentDoc();
   if (aImage == mCurrentRequest) {
     if (doc && (mCurrentRequestFlags & REQUEST_IS_TRACKED)) {
       mCurrentRequestFlags &= ~REQUEST_IS_TRACKED;
       doc->RemoveImage(mCurrentRequest,
                        (aFlags & REQUEST_DISCARD) ? nsIDocument::REQUEST_DISCARD : 0);
     }
     else if (aFlags & REQUEST_DISCARD) {
       // If we're not in the document we may still need to be discarded.
       aImage->RequestDiscard();
     }
   }
   if (aImage == mPendingRequest) {
     if (doc && (mPendingRequestFlags & REQUEST_IS_TRACKED)) {
       mPendingRequestFlags &= ~REQUEST_IS_TRACKED;
       doc->RemoveImage(mPendingRequest,
                        (aFlags & REQUEST_DISCARD) ? nsIDocument::REQUEST_DISCARD : 0);
     }
     else if (aFlags & REQUEST_DISCARD) {
       // If we're not in the document we may still need to be discarded.
       aImage->RequestDiscard();
     }
   }
 }
 void
 nsImageLoadingContent::CreateStaticImageClone(nsImageLoadingContent* aDest) const
 {
   aDest->mCurrentRequest = nsContentUtils::GetStaticRequest(mCurrentRequest);
   aDest->TrackImage(aDest->mCurrentRequest);
   aDest->mForcedImageState = mForcedImageState;
   aDest->mImageBlockingStatus = mImageBlockingStatus;
   aDest->mLoadingEnabled = mLoadingEnabled;
   aDest->mStateChangerDepth = mStateChangerDepth;
   aDest->mIsImageStateForced = mIsImageStateForced;
   aDest->mLoading = mLoading;
   aDest->mBroken = mBroken;
   aDest->mUserDisabled = mUserDisabled;
   aDest->mSuppressed = mSuppressed;
 }
 CORSMode
 nsImageLoadingContent::GetCORSMode()
 {
   return CORS_NONE;
 }
 nsImageLoadingContent::ImageObserver::ImageObserver(imgINotificationObserver* aObserver)
   : mObserver(aObserver)
   , mNext(nullptr)
 {
   MOZ_COUNT_CTOR(ImageObserver);
 }
 nsImageLoadingContent::ImageObserver::~ImageObserver()
 {
   MOZ_COUNT_DTOR(ImageObserver);
   NS_CONTENT_DELETE_LIST_MEMBER(ImageObserver, this, mNext);
 }

The Tor Browser / annotate

content/base/src/nsImageLoadingContent.cpp@deefc01c0e14 (annotated)

content/base/src/nsImageLoadingContent.cpp