The Tor Browser: image/src/imgRequest.cpp@ac0c01689b40 (annotated)

image/src/imgRequest.cpp@ac0c01689b40 (annotated)

image/src/imgRequest.cpp

Thu, 15 Jan 2015 15:59:08 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 15 Jan 2015 15:59:08 +0100
branch: TOR_BUG_9701
changeset 10: ac0c01689b40
permissions: -rw-r--r--

Implement a real Private Browsing Mode condition by changing the API/ABI;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.

 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 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/. */
 #include "imgRequest.h"
 #include "ImageLogging.h"
 #include "imgLoader.h"
 #include "imgRequestProxy.h"
 #include "imgStatusTracker.h"
 #include "ImageFactory.h"
 #include "Image.h"
 #include "RasterImage.h"
 #include "nsIChannel.h"
 #include "nsICachingChannel.h"
 #include "nsIThreadRetargetableRequest.h"
 #include "nsIInputStream.h"
 #include "nsIMultiPartChannel.h"
 #include "nsIHttpChannel.h"
 #include "nsIApplicationCache.h"
 #include "nsIApplicationCacheChannel.h"
 #include "nsMimeTypes.h"
 #include "nsIInterfaceRequestorUtils.h"
 #include "nsISupportsPrimitives.h"
 #include "nsIScriptSecurityManager.h"
 #include "nsContentUtils.h"
 #include "nsICacheEntry.h"
 #include "plstr.h" // PL_strcasestr(...)
 #include "nsNetUtil.h"
 #include "nsIProtocolHandler.h"
 #include "imgIRequest.h"
 using namespace mozilla;
 using namespace mozilla::image;
 #if defined(PR_LOGGING)
 PRLogModuleInfo *
 GetImgLog()
 {
   static PRLogModuleInfo *sImgLog;
   if (!sImgLog)
     sImgLog = PR_NewLogModule("imgRequest");
   return sImgLog;
 }
 #endif
 NS_IMPL_ISUPPORTS(imgRequest,
                   nsIStreamListener, nsIRequestObserver,
                   nsIThreadRetargetableStreamListener,
                   nsIChannelEventSink,
                   nsIInterfaceRequestor,
                   nsIAsyncVerifyRedirectCallback)
 imgRequest::imgRequest(imgLoader* aLoader)
  : mLoader(aLoader)
  , mStatusTracker(new imgStatusTracker(nullptr))
  , mValidator(nullptr)
  , mInnerWindowId(0)
  , mCORSMode(imgIRequest::CORS_NONE)
  , mDecodeRequested(false)
  , mIsMultiPartChannel(false)
  , mGotData(false)
  , mIsInCache(false)
  , mResniffMimeType(false)
 { }
 imgRequest::~imgRequest()
 {
   if (mURI) {
     nsAutoCString spec;
     mURI->GetSpec(spec);
     LOG_FUNC_WITH_PARAM(GetImgLog(), "imgRequest::~imgRequest()", "keyuri", spec.get());
   } else
     LOG_FUNC(GetImgLog(), "imgRequest::~imgRequest()");
 }
 nsresult imgRequest::Init(nsIURI *aURI,
                           nsIURI *aCurrentURI,
                           nsIURI *aFirstPartyIsolationURI,
                           nsIRequest *aRequest,
                           nsIChannel *aChannel,
                           imgCacheEntry *aCacheEntry,
                           void *aLoadId,
                           nsIPrincipal* aLoadingPrincipal,
                           int32_t aCORSMode)
 {
   MOZ_ASSERT(NS_IsMainThread(), "Cannot use nsIURI off main thread!");
   LOG_FUNC(GetImgLog(), "imgRequest::Init");
   NS_ABORT_IF_FALSE(!mImage, "Multiple calls to init");
   NS_ABORT_IF_FALSE(aURI, "No uri");
   NS_ABORT_IF_FALSE(aCurrentURI, "No current uri");
   NS_ABORT_IF_FALSE(aRequest, "No request");
   NS_ABORT_IF_FALSE(aChannel, "No channel");
   mProperties = do_CreateInstance("@mozilla.org/properties;1");
   // Use ImageURL to ensure access to URI data off main thread.
   mURI = new ImageURL(aURI);
   mCurrentURI = aCurrentURI;
   mFirstPartyIsolationURI = aFirstPartyIsolationURI;
   mRequest = aRequest;
   mChannel = aChannel;
   mTimedChannel = do_QueryInterface(mChannel);
   mLoadingPrincipal = aLoadingPrincipal;
   mCORSMode = aCORSMode;
   mChannel->GetNotificationCallbacks(getter_AddRefs(mPrevChannelSink));
   NS_ASSERTION(mPrevChannelSink != this,
                "Initializing with a channel that already calls back to us!");
   mChannel->SetNotificationCallbacks(this);
   mCacheEntry = aCacheEntry;
   SetLoadId(aLoadId);
   return NS_OK;
 }
 already_AddRefed<imgStatusTracker>
 imgRequest::GetStatusTracker()
 {
   if (mImage && mGotData) {
     NS_ABORT_IF_FALSE(!mStatusTracker,
                       "Should have given mStatusTracker to mImage");
     return mImage->GetStatusTracker();
   } else {
     NS_ABORT_IF_FALSE(mStatusTracker,
                       "Should have mStatusTracker until we create mImage");
     nsRefPtr<imgStatusTracker> statusTracker = mStatusTracker;
     MOZ_ASSERT(statusTracker);
     return statusTracker.forget();
   }
 }
 void imgRequest::SetCacheEntry(imgCacheEntry *entry)
 {
   mCacheEntry = entry;
 }
 bool imgRequest::HasCacheEntry() const
 {
   return mCacheEntry != nullptr;
 }
 void imgRequest::ResetCacheEntry()
 {
   if (HasCacheEntry()) {
     mCacheEntry->SetDataSize(0);
   }
 }
 void imgRequest::AddProxy(imgRequestProxy *proxy)
 {
   NS_PRECONDITION(proxy, "null imgRequestProxy passed in");
   LOG_SCOPE_WITH_PARAM(GetImgLog(), "imgRequest::AddProxy", "proxy", proxy);
   // If we're empty before adding, we have to tell the loader we now have
   // proxies.
   nsRefPtr<imgStatusTracker> statusTracker = GetStatusTracker();
   if (statusTracker->ConsumerCount() == 0) {
     NS_ABORT_IF_FALSE(mURI, "Trying to SetHasProxies without key uri.");
     mLoader->SetHasProxies(mFirstPartyIsolationURI, mURI);
   }
   statusTracker->AddConsumer(proxy);
 }
 nsresult imgRequest::RemoveProxy(imgRequestProxy *proxy, nsresult aStatus)
 {
   LOG_SCOPE_WITH_PARAM(GetImgLog(), "imgRequest::RemoveProxy", "proxy", proxy);
   // This will remove our animation consumers, so after removing
   // this proxy, we don't end up without proxies with observers, but still
   // have animation consumers.
   proxy->ClearAnimationConsumers();
   // Let the status tracker do its thing before we potentially call Cancel()
   // below, because Cancel() may result in OnStopRequest being called back
   // before Cancel() returns, leaving the image in a different state then the
   // one it was in at this point.
   nsRefPtr<imgStatusTracker> statusTracker = GetStatusTracker();
   if (!statusTracker->RemoveConsumer(proxy, aStatus))
     return NS_OK;
   if (statusTracker->ConsumerCount() == 0) {
     // If we have no observers, there's nothing holding us alive. If we haven't
     // been cancelled and thus removed from the cache, tell the image loader so
     // we can be evicted from the cache.
     if (mCacheEntry) {
       NS_ABORT_IF_FALSE(mURI, "Removing last observer without key uri.");
       mLoader->SetHasNoProxies(mURI, mCacheEntry);
     }
 #if defined(PR_LOGGING)
     else {
       nsAutoCString spec;
       mURI->GetSpec(spec);
       LOG_MSG_WITH_PARAM(GetImgLog(), "imgRequest::RemoveProxy no cache entry", "uri", spec.get());
     }
 #endif
     /* If |aStatus| is a failure code, then cancel the load if it is still in progress.
        Otherwise, let the load continue, keeping 'this' in the cache with no observers.
        This way, if a proxy is destroyed without calling cancel on it, it won't leak
        and won't leave a bad pointer in the observer list.
      */
     if (statusTracker->IsLoading() && NS_FAILED(aStatus)) {
       LOG_MSG(GetImgLog(), "imgRequest::RemoveProxy", "load in progress.  canceling");
       this->Cancel(NS_BINDING_ABORTED);
     }
     /* break the cycle from the cache entry. */
     mCacheEntry = nullptr;
   }
   // If a proxy is removed for a reason other than its owner being
   // changed, remove the proxy from the loadgroup.
   if (aStatus != NS_IMAGELIB_CHANGING_OWNER)
     proxy->RemoveFromLoadGroup(true);
   return NS_OK;
 }
 void imgRequest::CancelAndAbort(nsresult aStatus)
 {
   LOG_SCOPE(GetImgLog(), "imgRequest::CancelAndAbort");
   Cancel(aStatus);
   // It's possible for the channel to fail to open after we've set our
   // notification callbacks. In that case, make sure to break the cycle between
   // the channel and us, because it won't.
   if (mChannel) {
     mChannel->SetNotificationCallbacks(mPrevChannelSink);
     mPrevChannelSink = nullptr;
   }
 }
 class imgRequestMainThreadCancel : public nsRunnable
 {
 public:
   imgRequestMainThreadCancel(imgRequest *aImgRequest, nsresult aStatus)
     : mImgRequest(aImgRequest)
     , mStatus(aStatus)
   {
     MOZ_ASSERT(!NS_IsMainThread(), "Create me off main thread only!");
     MOZ_ASSERT(aImgRequest);
   }
   NS_IMETHOD Run()
   {
     MOZ_ASSERT(NS_IsMainThread(), "I should be running on the main thread!");
     mImgRequest->ContinueCancel(mStatus);
     return NS_OK;
   }
 private:
   nsRefPtr<imgRequest> mImgRequest;
   nsresult mStatus;
 };
 void imgRequest::Cancel(nsresult aStatus)
 {
   /* The Cancel() method here should only be called by this class. */
   LOG_SCOPE(GetImgLog(), "imgRequest::Cancel");
   nsRefPtr<imgStatusTracker> statusTracker = GetStatusTracker();
   statusTracker->MaybeUnblockOnload();
   statusTracker->RecordCancel();
   if (NS_IsMainThread()) {
     ContinueCancel(aStatus);
   } else {
     NS_DispatchToMainThread(new imgRequestMainThreadCancel(this, aStatus));
   }
 }
 void imgRequest::ContinueCancel(nsresult aStatus)
 {
   MOZ_ASSERT(NS_IsMainThread());
   RemoveFromCache();
   nsRefPtr<imgStatusTracker> statusTracker = GetStatusTracker();
   if (mRequest && statusTracker->IsLoading()) {
      mRequest->Cancel(aStatus);
   }
 }
 nsresult imgRequest::GetURI(ImageURL **aURI)
 {
   MOZ_ASSERT(aURI);
   LOG_FUNC(GetImgLog(), "imgRequest::GetURI");
   if (mURI) {
     *aURI = mURI;
     NS_ADDREF(*aURI);
     return NS_OK;
   }
   return NS_ERROR_FAILURE;
 }
 nsresult imgRequest::GetSecurityInfo(nsISupports **aSecurityInfo)
 {
   LOG_FUNC(GetImgLog(), "imgRequest::GetSecurityInfo");
   // Missing security info means this is not a security load
   // i.e. it is not an error when security info is missing
   NS_IF_ADDREF(*aSecurityInfo = mSecurityInfo);
   return NS_OK;
 }
 void imgRequest::RemoveFromCache()
 {
   LOG_SCOPE(GetImgLog(), "imgRequest::RemoveFromCache");
   if (mIsInCache) {
     // mCacheEntry is nulled out when we have no more observers.
     if (mCacheEntry)
       mLoader->RemoveFromCache(mCacheEntry);
     else {
       mLoader->RemoveFromCache(mLoader->GetCacheKey(mFirstPartyIsolationURI, mURI, nullptr),
                                mLoader->GetCache(mURI),
                                mLoader->GetCacheQueue(mURI));
     }
   }
   mCacheEntry = nullptr;
 }
 int32_t imgRequest::Priority() const
 {
   int32_t priority = nsISupportsPriority::PRIORITY_NORMAL;
   nsCOMPtr<nsISupportsPriority> p = do_QueryInterface(mRequest);
   if (p)
     p->GetPriority(&priority);
   return priority;
 }
 void imgRequest::AdjustPriority(imgRequestProxy *proxy, int32_t delta)
 {
   // only the first proxy is allowed to modify the priority of this image load.
   //
   // XXX(darin): this is probably not the most optimal algorithm as we may want
   // to increase the priority of requests that have a lot of proxies.  the key
   // concern though is that image loads remain lower priority than other pieces
   // of content such as link clicks, CSS, and JS.
   //
   nsRefPtr<imgStatusTracker> statusTracker = GetStatusTracker();
   if (!statusTracker->FirstConsumerIs(proxy))
     return;
   nsCOMPtr<nsISupportsPriority> p = do_QueryInterface(mChannel);
   if (p)
     p->AdjustPriority(delta);
 }
 void imgRequest::SetIsInCache(bool incache)
 {
   LOG_FUNC_WITH_PARAM(GetImgLog(), "imgRequest::SetIsCacheable", "incache", incache);
   mIsInCache = incache;
 }
 void imgRequest::UpdateCacheEntrySize()
 {
   if (mCacheEntry)
     mCacheEntry->SetDataSize(mImage->SizeOfData());
 }
 void imgRequest::SetCacheValidation(imgCacheEntry* aCacheEntry, nsIRequest* aRequest)
 {
   /* get the expires info */
   if (aCacheEntry) {
     nsCOMPtr<nsICachingChannel> cacheChannel(do_QueryInterface(aRequest));
     if (cacheChannel) {
       nsCOMPtr<nsISupports> cacheToken;
       cacheChannel->GetCacheToken(getter_AddRefs(cacheToken));
       if (cacheToken) {
         nsCOMPtr<nsICacheEntry> entryDesc(do_QueryInterface(cacheToken));
         if (entryDesc) {
           uint32_t expiration;
           /* get the expiration time from the caching channel's token */
           entryDesc->GetExpirationTime(&expiration);
           // Expiration time defaults to 0. We set the expiration time on our
           // entry if it hasn't been set yet.
           if (aCacheEntry->GetExpiryTime() == 0)
             aCacheEntry->SetExpiryTime(expiration);
         }
       }
     }
     // Determine whether the cache entry must be revalidated when we try to use it.
     // Currently, only HTTP specifies this information...
     nsCOMPtr<nsIHttpChannel> httpChannel(do_QueryInterface(aRequest));
     if (httpChannel) {
       bool bMustRevalidate = false;
       httpChannel->IsNoStoreResponse(&bMustRevalidate);
       if (!bMustRevalidate) {
         httpChannel->IsNoCacheResponse(&bMustRevalidate);
       }
       if (!bMustRevalidate) {
         nsAutoCString cacheHeader;
         httpChannel->GetResponseHeader(NS_LITERAL_CSTRING("Cache-Control"),
                                             cacheHeader);
         if (PL_strcasestr(cacheHeader.get(), "must-revalidate")) {
           bMustRevalidate = true;
         }
       }
       // Cache entries default to not needing to validate. We ensure that
       // multiple calls to this function don't override an earlier decision to
       // validate by making validation a one-way decision.
       if (bMustRevalidate)
         aCacheEntry->SetMustValidate(bMustRevalidate);
     }
     // We always need to validate file URIs.
     nsCOMPtr<nsIChannel> channel = do_QueryInterface(aRequest);
     if (channel) {
       nsCOMPtr<nsIURI> uri;
       channel->GetURI(getter_AddRefs(uri));
       bool isfile = false;
       uri->SchemeIs("file", &isfile);
       if (isfile)
         aCacheEntry->SetMustValidate(isfile);
     }
   }
 }
 namespace { // anon
 already_AddRefed<nsIApplicationCache>
 GetApplicationCache(nsIRequest* aRequest)
 {
   nsresult rv;
   nsCOMPtr<nsIApplicationCacheChannel> appCacheChan = do_QueryInterface(aRequest);
   if (!appCacheChan) {
     return nullptr;
   }
   bool fromAppCache;
   rv = appCacheChan->GetLoadedFromApplicationCache(&fromAppCache);
   NS_ENSURE_SUCCESS(rv, nullptr);
   if (!fromAppCache) {
     return nullptr;
   }
   nsCOMPtr<nsIApplicationCache> appCache;
   rv = appCacheChan->GetApplicationCache(getter_AddRefs(appCache));
   NS_ENSURE_SUCCESS(rv, nullptr);
   return appCache.forget();
 }
 } // anon
 bool
 imgRequest::CacheChanged(nsIRequest* aNewRequest)
 {
   nsCOMPtr<nsIApplicationCache> newAppCache = GetApplicationCache(aNewRequest);
   // Application cache not involved at all or the same app cache involved
   // in both of the loads (original and new).
   if (newAppCache == mApplicationCache)
     return false;
   // In a rare case it may happen that two objects still refer
   // the same application cache version.
   if (newAppCache && mApplicationCache) {
     nsresult rv;
     nsAutoCString oldAppCacheClientId, newAppCacheClientId;
     rv = mApplicationCache->GetClientID(oldAppCacheClientId);
     NS_ENSURE_SUCCESS(rv, true);
     rv = newAppCache->GetClientID(newAppCacheClientId);
     NS_ENSURE_SUCCESS(rv, true);
     if (oldAppCacheClientId == newAppCacheClientId)
       return false;
   }
   // When we get here, app caches differ or app cache is involved
   // just in one of the loads what we also consider as a change
   // in a loading cache.
   return true;
 }
 nsresult
 imgRequest::LockImage()
 {
   return mImage->LockImage();
 }
 nsresult
 imgRequest::UnlockImage()
 {
   return mImage->UnlockImage();
 }
 nsresult
 imgRequest::RequestDecode()
 {
   // If we've initialized our image, we can request a decode.
   if (mImage) {
     return mImage->RequestDecode();
   }
   // Otherwise, flag to do it when we get the image
   mDecodeRequested = true;
   return NS_OK;
 }
 nsresult
 imgRequest::StartDecoding()
 {
   // If we've initialized our image, we can request a decode.
   if (mImage) {
     return mImage->StartDecoding();
   }
   // Otherwise, flag to do it when we get the image
   mDecodeRequested = true;
   return NS_OK;
 }
 /** nsIRequestObserver methods **/
 /* void onStartRequest (in nsIRequest request, in nsISupports ctxt); */
 NS_IMETHODIMP imgRequest::OnStartRequest(nsIRequest *aRequest, nsISupports *ctxt)
 {
   LOG_SCOPE(GetImgLog(), "imgRequest::OnStartRequest");
   // Figure out if we're multipart
   nsCOMPtr<nsIMultiPartChannel> mpchan(do_QueryInterface(aRequest));
   nsRefPtr<imgStatusTracker> statusTracker = GetStatusTracker();
   if (mpchan) {
     mIsMultiPartChannel = true;
     statusTracker->SetIsMultipart();
   }
   // If we're not multipart, we shouldn't have an image yet
   NS_ABORT_IF_FALSE(mIsMultiPartChannel || !mImage,
                     "Already have an image for non-multipart request");
   // If we're multipart and about to load another image, signal so we can
   // detect the mime type in OnDataAvailable.
   if (mIsMultiPartChannel && mImage) {
     mResniffMimeType = true;
     // Tell the image to reinitialize itself. We have to do this in
     // OnStartRequest so that its state machine is always in a consistent
     // state.
     // Note that if our MIME type changes, mImage will be replaced with a
     // new object.
     mImage->OnNewSourceData();
   }
   /*
    * If mRequest is null here, then we need to set it so that we'll be able to
    * cancel it if our Cancel() method is called.  Note that this can only
    * happen for multipart channels.  We could simply not null out mRequest for
    * non-last parts, if GetIsLastPart() were reliable, but it's not.  See
    * https://bugzilla.mozilla.org/show_bug.cgi?id=339610
    */
   if (!mRequest) {
     NS_ASSERTION(mpchan,
                  "We should have an mRequest here unless we're multipart");
     nsCOMPtr<nsIChannel> chan;
     mpchan->GetBaseChannel(getter_AddRefs(chan));
     mRequest = chan;
   }
   // Note: refreshing statusTracker in case OnNewSourceData changed it.
   statusTracker = GetStatusTracker();
   statusTracker->OnStartRequest();
   nsCOMPtr<nsIChannel> channel(do_QueryInterface(aRequest));
   if (channel)
     channel->GetSecurityInfo(getter_AddRefs(mSecurityInfo));
   /* Get our principal */
   nsCOMPtr<nsIChannel> chan(do_QueryInterface(aRequest));
   if (chan) {
     nsCOMPtr<nsIScriptSecurityManager> secMan = nsContentUtils::GetSecurityManager();
     if (secMan) {
       nsresult rv = secMan->GetChannelPrincipal(chan,
                                                 getter_AddRefs(mPrincipal));
       if (NS_FAILED(rv)) {
         return rv;
       }
     }
   }
   SetCacheValidation(mCacheEntry, aRequest);
   mApplicationCache = GetApplicationCache(aRequest);
   // Shouldn't we be dead already if this gets hit?  Probably multipart/x-mixed-replace...
   if (statusTracker->ConsumerCount() == 0) {
     this->Cancel(NS_IMAGELIB_ERROR_FAILURE);
   }
   // Try to retarget OnDataAvailable to a decode thread.
   nsCOMPtr<nsIHttpChannel> httpChannel = do_QueryInterface(aRequest);
   nsCOMPtr<nsIThreadRetargetableRequest> retargetable =
     do_QueryInterface(aRequest);
   if (httpChannel && retargetable &&
       ImageFactory::CanRetargetOnDataAvailable(mURI, mIsMultiPartChannel)) {
     nsAutoCString mimeType;
     nsresult rv = httpChannel->GetContentType(mimeType);
     if (NS_SUCCEEDED(rv) && !mimeType.EqualsLiteral(IMAGE_SVG_XML)) {
       // Image object not created until OnDataAvailable, so forward to static
       // DecodePool directly.
       nsCOMPtr<nsIEventTarget> target = RasterImage::GetEventTarget();
       rv = retargetable->RetargetDeliveryTo(target);
     }
     PR_LOG(GetImgLog(), PR_LOG_WARNING,
            ("[this=%p] imgRequest::OnStartRequest -- "
             "RetargetDeliveryTo rv %d=%s\n",
             this, rv, NS_SUCCEEDED(rv) ? "succeeded" : "failed"));
   }
   return NS_OK;
 }
 /* void onStopRequest (in nsIRequest request, in nsISupports ctxt, in nsresult status); */
 NS_IMETHODIMP imgRequest::OnStopRequest(nsIRequest *aRequest, nsISupports *ctxt, nsresult status)
 {
   LOG_FUNC(GetImgLog(), "imgRequest::OnStopRequest");
   // XXXldb What if this is a non-last part of a multipart request?
   // xxx before we release our reference to mRequest, lets
   // save the last status that we saw so that the
   // imgRequestProxy will have access to it.
   if (mRequest) {
     mRequest = nullptr;  // we no longer need the request
   }
   // stop holding a ref to the channel, since we don't need it anymore
   if (mChannel) {
     mChannel->SetNotificationCallbacks(mPrevChannelSink);
     mPrevChannelSink = nullptr;
     mChannel = nullptr;
   }
   bool lastPart = true;
   nsCOMPtr<nsIMultiPartChannel> mpchan(do_QueryInterface(aRequest));
   if (mpchan)
     mpchan->GetIsLastPart(&lastPart);
   // Tell the image that it has all of the source data. Note that this can
   // trigger a failure, since the image might be waiting for more non-optional
   // data and this is the point where we break the news that it's not coming.
   if (mImage) {
     nsresult rv = mImage->OnImageDataComplete(aRequest, ctxt, status, lastPart);
     // If we got an error in the OnImageDataComplete() call, we don't want to
     // proceed as if nothing bad happened. However, we also want to give
     // precedence to failure status codes from necko, since presumably they're
     // more meaningful.
     if (NS_FAILED(rv) && NS_SUCCEEDED(status))
       status = rv;
   }
   // If the request went through, update the cache entry size. Otherwise,
   // cancel the request, which removes us from the cache.
   if (mImage && NS_SUCCEEDED(status)) {
     // We update the cache entry size here because this is where we finish
     // loading compressed source data, which is part of our size calculus.
     UpdateCacheEntrySize();
   }
   else {
     // stops animations, removes from cache
     this->Cancel(status);
   }
   if (!mImage) {
     // We have to fire imgStatusTracker::OnStopRequest ourselves because there's
     // no image capable of doing so.
     nsRefPtr<imgStatusTracker> statusTracker = GetStatusTracker();
     statusTracker->OnStopRequest(lastPart, status);
   }
   mTimedChannel = nullptr;
   return NS_OK;
 }
 struct mimetype_closure
 {
   nsACString* newType;
 };
 /* prototype for these defined below */
 static NS_METHOD sniff_mimetype_callback(nsIInputStream* in, void* closure, const char* fromRawSegment,
                                          uint32_t toOffset, uint32_t count, uint32_t *writeCount);
 /** nsThreadRetargetableStreamListener methods **/
 NS_IMETHODIMP
 imgRequest::CheckListenerChain()
 {
   // TODO Might need more checking here.
   NS_ASSERTION(NS_IsMainThread(), "Should be on the main thread!");
   return NS_OK;
 }
 /** nsIStreamListener methods **/
 /* void onDataAvailable (in nsIRequest request, in nsISupports ctxt, in nsIInputStream inStr, in unsigned long long sourceOffset, in unsigned long count); */
 NS_IMETHODIMP
 imgRequest::OnDataAvailable(nsIRequest *aRequest, nsISupports *ctxt,
                             nsIInputStream *inStr, uint64_t sourceOffset,
                             uint32_t count)
 {
   LOG_SCOPE_WITH_PARAM(GetImgLog(), "imgRequest::OnDataAvailable", "count", count);
   NS_ASSERTION(aRequest, "imgRequest::OnDataAvailable -- no request!");
   nsresult rv;
   if (!mGotData || mResniffMimeType) {
     LOG_SCOPE(GetImgLog(), "imgRequest::OnDataAvailable |First time through... finding mimetype|");
     mGotData = true;
     // Store and reset this for the invariant that it's always false after
     // calls to OnDataAvailable (see bug 907575)
     bool resniffMimeType = mResniffMimeType;
     mResniffMimeType = false;
     mimetype_closure closure;
     nsAutoCString newType;
     closure.newType = &newType;
     /* look at the first few bytes and see if we can tell what the data is from that
      * since servers tend to lie. :(
      */
     uint32_t out;
     inStr->ReadSegments(sniff_mimetype_callback, &closure, count, &out);
     nsCOMPtr<nsIChannel> chan(do_QueryInterface(aRequest));
     if (newType.IsEmpty()) {
       LOG_SCOPE(GetImgLog(), "imgRequest::OnDataAvailable |sniffing of mimetype failed|");
       rv = NS_ERROR_FAILURE;
       if (chan) {
         rv = chan->GetContentType(newType);
       }
       if (NS_FAILED(rv)) {
         PR_LOG(GetImgLog(), PR_LOG_ERROR,
                ("[this=%p] imgRequest::OnDataAvailable -- Content type unavailable from the channel\n",
                 this));
         this->Cancel(NS_IMAGELIB_ERROR_FAILURE);
         return NS_BINDING_ABORTED;
       }
       LOG_MSG(GetImgLog(), "imgRequest::OnDataAvailable", "Got content type from the channel");
     }
     // If we're a regular image and this is the first call to OnDataAvailable,
     // this will always be true. If we've resniffed our MIME type (i.e. we're a
     // multipart/x-mixed-replace image), we have to be able to switch our image
     // type and decoder.
     // We always reinitialize for SVGs, because they have no way of
     // reinitializing themselves.
     if (mContentType != newType || newType.EqualsLiteral(IMAGE_SVG_XML)) {
       mContentType = newType;
       // If we've resniffed our MIME type and it changed, we need to create a
       // new status tracker to give to the image, because we don't have one of
       // our own any more.
       if (resniffMimeType) {
         NS_ABORT_IF_FALSE(mIsMultiPartChannel, "Resniffing a non-multipart image");
         nsRefPtr<imgStatusTracker> freshTracker = new imgStatusTracker(nullptr);
         nsRefPtr<imgStatusTracker> oldStatusTracker = GetStatusTracker();
         freshTracker->AdoptConsumers(oldStatusTracker);
         mStatusTracker = freshTracker.forget();
       }
       SetProperties(chan);
       LOG_MSG_WITH_PARAM(GetImgLog(), "imgRequest::OnDataAvailable", "content type", mContentType.get());
       // XXX If server lied about mimetype and it's SVG, we may need to copy
       // the data and dispatch back to the main thread, AND tell the channel to
       // dispatch there in the future.
       // Now we can create a new image to hold the data. If we don't have a decoder
       // for this mimetype we'll find out about it here.
       mImage = ImageFactory::CreateImage(aRequest, mStatusTracker, mContentType,
                                          mURI, mIsMultiPartChannel,
                                          static_cast<uint32_t>(mInnerWindowId));
       // Release our copy of the status tracker since the image owns it now.
       mStatusTracker = nullptr;
       // Notify listeners that we have an image.
       // XXX(seth): The name of this notification method is pretty misleading.
       nsRefPtr<imgStatusTracker> statusTracker = GetStatusTracker();
       statusTracker->OnDataAvailable();
       if (mImage->HasError() && !mIsMultiPartChannel) { // Probably bad mimetype
         // We allow multipart images to fail to initialize without cancelling the
         // load because subsequent images might be fine; thus only single part
         // images end up here.
         this->Cancel(NS_ERROR_FAILURE);
         return NS_BINDING_ABORTED;
       }
       NS_ABORT_IF_FALSE(statusTracker->HasImage(), "Status tracker should have an image!");
       NS_ABORT_IF_FALSE(mImage, "imgRequest should have an image!");
       if (mDecodeRequested)
         mImage->StartDecoding();
     }
   }
   // Notify the image that it has new data.
   rv = mImage->OnImageDataAvailable(aRequest, ctxt, inStr, sourceOffset, count);
   if (NS_FAILED(rv)) {
     PR_LOG(GetImgLog(), PR_LOG_WARNING,
            ("[this=%p] imgRequest::OnDataAvailable -- "
             "copy to RasterImage failed\n", this));
     this->Cancel(NS_IMAGELIB_ERROR_FAILURE);
     return NS_BINDING_ABORTED;
   }
   return NS_OK;
 }
 class SetPropertiesEvent : public nsRunnable
 {
 public:
   SetPropertiesEvent(imgRequest* aImgRequest, nsIChannel* aChan)
     : mImgRequest(aImgRequest)
     , mChan(aChan)
   {
     MOZ_ASSERT(!NS_IsMainThread(), "Should be created off the main thread");
     MOZ_ASSERT(aImgRequest, "aImgRequest cannot be null");
   }
   NS_IMETHOD Run()
   {
     MOZ_ASSERT(NS_IsMainThread(), "Should run on the main thread only");
     MOZ_ASSERT(mImgRequest, "mImgRequest cannot be null");
     mImgRequest->SetProperties(mChan);
     return NS_OK;
   }
 private:
   nsRefPtr<imgRequest> mImgRequest;
   nsCOMPtr<nsIChannel> mChan;
 };
 void
 imgRequest::SetProperties(nsIChannel* aChan)
 {
   // Force execution on main thread since some property objects are non
   // threadsafe.
   if (!NS_IsMainThread()) {
     NS_DispatchToMainThread(new SetPropertiesEvent(this, aChan));
     return;
   }
   /* set our mimetype as a property */
   nsCOMPtr<nsISupportsCString> contentType(do_CreateInstance("@mozilla.org/supports-cstring;1"));
   if (contentType) {
     contentType->SetData(mContentType);
     mProperties->Set("type", contentType);
   }
   /* set our content disposition as a property */
   nsAutoCString disposition;
   if (aChan) {
     aChan->GetContentDispositionHeader(disposition);
   }
   if (!disposition.IsEmpty()) {
     nsCOMPtr<nsISupportsCString> contentDisposition(do_CreateInstance("@mozilla.org/supports-cstring;1"));
     if (contentDisposition) {
       contentDisposition->SetData(disposition);
       mProperties->Set("content-disposition", contentDisposition);
     }
   }
 }
 static NS_METHOD sniff_mimetype_callback(nsIInputStream* in,
                                          void* data,
                                          const char* fromRawSegment,
                                          uint32_t toOffset,
                                          uint32_t count,
                                          uint32_t *writeCount)
 {
   mimetype_closure* closure = static_cast<mimetype_closure*>(data);
   NS_ASSERTION(closure, "closure is null!");
   if (count > 0)
     imgLoader::GetMimeTypeFromContent(fromRawSegment, count, *closure->newType);
   *writeCount = 0;
   return NS_ERROR_FAILURE;
 }
 /** nsIInterfaceRequestor methods **/
 NS_IMETHODIMP
 imgRequest::GetInterface(const nsIID & aIID, void **aResult)
 {
   if (!mPrevChannelSink || aIID.Equals(NS_GET_IID(nsIChannelEventSink)))
     return QueryInterface(aIID, aResult);
   NS_ASSERTION(mPrevChannelSink != this,
                "Infinite recursion - don't keep track of channel sinks that are us!");
   return mPrevChannelSink->GetInterface(aIID, aResult);
 }
 /** nsIChannelEventSink methods **/
 NS_IMETHODIMP
 imgRequest::AsyncOnChannelRedirect(nsIChannel *oldChannel,
                                    nsIChannel *newChannel, uint32_t flags,
                                    nsIAsyncVerifyRedirectCallback *callback)
 {
   NS_ASSERTION(mRequest && mChannel, "Got a channel redirect after we nulled out mRequest!");
   NS_ASSERTION(mChannel == oldChannel, "Got a channel redirect for an unknown channel!");
   NS_ASSERTION(newChannel, "Got a redirect to a NULL channel!");
   SetCacheValidation(mCacheEntry, oldChannel);
   // Prepare for callback
   mRedirectCallback = callback;
   mNewRedirectChannel = newChannel;
   nsCOMPtr<nsIChannelEventSink> sink(do_GetInterface(mPrevChannelSink));
   if (sink) {
     nsresult rv = sink->AsyncOnChannelRedirect(oldChannel, newChannel, flags,
                                                this);
     if (NS_FAILED(rv)) {
         mRedirectCallback = nullptr;
         mNewRedirectChannel = nullptr;
     }
     return rv;
   }
   (void) OnRedirectVerifyCallback(NS_OK);
   return NS_OK;
 }
 NS_IMETHODIMP
 imgRequest::OnRedirectVerifyCallback(nsresult result)
 {
   NS_ASSERTION(mRedirectCallback, "mRedirectCallback not set in callback");
   NS_ASSERTION(mNewRedirectChannel, "mNewRedirectChannel not set in callback");
   if (NS_FAILED(result)) {
       mRedirectCallback->OnRedirectVerifyCallback(result);
       mRedirectCallback = nullptr;
       mNewRedirectChannel = nullptr;
       return NS_OK;
   }
   mChannel = mNewRedirectChannel;
   mTimedChannel = do_QueryInterface(mChannel);
   mNewRedirectChannel = nullptr;
 #if defined(PR_LOGGING)
   nsAutoCString oldspec;
   if (mCurrentURI)
     mCurrentURI->GetSpec(oldspec);
   LOG_MSG_WITH_PARAM(GetImgLog(), "imgRequest::OnChannelRedirect", "old", oldspec.get());
 #endif
   // make sure we have a protocol that returns data rather than opens
   // an external application, e.g. mailto:
   mChannel->GetURI(getter_AddRefs(mCurrentURI));
   bool doesNotReturnData = false;
   nsresult rv =
     NS_URIChainHasFlags(mCurrentURI, nsIProtocolHandler::URI_DOES_NOT_RETURN_DATA,
                         &doesNotReturnData);
   if (NS_SUCCEEDED(rv) && doesNotReturnData)
     rv = NS_ERROR_ABORT;
   if (NS_FAILED(rv)) {
     mRedirectCallback->OnRedirectVerifyCallback(rv);
     mRedirectCallback = nullptr;
     return NS_OK;
   }
   mRedirectCallback->OnRedirectVerifyCallback(NS_OK);
   mRedirectCallback = nullptr;
   return NS_OK;
 }

The Tor Browser / annotate

image/src/imgRequest.cpp@ac0c01689b40 (annotated)

image/src/imgRequest.cpp