The Tor Browser: layout/style/Loader.cpp@deefc01c0e14 (annotated)

layout/style/Loader.cpp@deefc01c0e14 (annotated)

layout/style/Loader.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/.
  *
  * This Original Code has been modified by IBM Corporation.
  * Modifications made by IBM described herein are Copyright (c)
  * International Business Machines Corporation, 2000.  Modifications
  * to Mozilla code or documentation identified per MPL Section 3.3
  *
  * Date             Modified by     Description of modification
  * 04/20/2000       IBM Corp.      OS/2 VisualAge build.
  */
 /* loading of CSS style sheets using the network APIs */
 #include "mozilla/ArrayUtils.h"
 #include "mozilla/MemoryReporting.h"
 #include "mozilla/css/Loader.h"
 #include "nsIRunnable.h"
 #include "nsIUnicharStreamLoader.h"
 #include "nsSyncLoadService.h"
 #include "nsCOMPtr.h"
 #include "nsString.h"
 #include "nsIContent.h"
 #include "nsIDocument.h"
 #include "nsIDOMNode.h"
 #include "nsIDOMDocument.h"
 #include "nsIURI.h"
 #include "nsNetUtil.h"
 #include "nsContentUtils.h"
 #include "nsIScriptSecurityManager.h"
 #include "nsContentPolicyUtils.h"
 #include "nsIHttpChannel.h"
 #include "nsIHttpChannelInternal.h"
 #include "nsIScriptError.h"
 #include "nsMimeTypes.h"
 #include "nsCSSStyleSheet.h"
 #include "nsIStyleSheetLinkingElement.h"
 #include "nsICSSLoaderObserver.h"
 #include "nsCSSParser.h"
 #include "mozilla/css/ImportRule.h"
 #include "nsThreadUtils.h"
 #include "nsGkAtoms.h"
 #include "nsIThreadInternal.h"
 #include "nsCrossSiteListenerProxy.h"
 #include "nsINetworkSeer.h"
 #include "mozilla/dom/ShadowRoot.h"
 #include "mozilla/dom/URL.h"
 #ifdef MOZ_XUL
 #include "nsXULPrototypeCache.h"
 #endif
 #include "nsIMediaList.h"
 #include "nsIDOMStyleSheet.h"
 #include "nsError.h"
 #include "nsIChannelPolicy.h"
 #include "nsIContentSecurityPolicy.h"
 #include "nsCycleCollectionParticipant.h"
 #include "mozilla/dom/EncodingUtils.h"
 using mozilla::dom::EncodingUtils;
 using namespace mozilla::dom;
 /**
  * OVERALL ARCHITECTURE
  *
  * The CSS Loader gets requests to load various sorts of style sheets:
  * inline style from <style> elements, linked style, @import-ed child
  * sheets, non-document sheets.  The loader handles the following tasks:
  *
  * 1) Checking whether the load is allowed: CheckLoadAllowed()
  * 2) Creation of the actual style sheet objects: CreateSheet()
  * 3) setting of the right media, title, enabled state, etc on the
  *    sheet: PrepareSheet()
  * 4) Insertion of the sheet in the proper cascade order:
  *    InsertSheetInDoc() and InsertChildSheet()
  * 5) Load of the sheet: LoadSheet()
  * 6) Parsing of the sheet: ParseSheet()
  * 7) Cleanup: SheetComplete()
  *
  * The detailed documentation for these functions is found with the
  * function implementations.
  *
  * The following helper object is used:
  *    SheetLoadData -- a small class that is used to store all the
  *                     information needed for the loading of a sheet;
  *                     this class handles listening for the stream
  *                     loader completion and also handles charset
  *                     determination.
  */
 namespace mozilla {
 namespace css {
 /*********************************************
  * Data needed to properly load a stylesheet *
  *********************************************/
 class SheetLoadData : public nsIRunnable,
                       public nsIUnicharStreamLoaderObserver,
                       public nsIThreadObserver
 {
 public:
   virtual ~SheetLoadData(void);
   // Data for loading a sheet linked from a document
   SheetLoadData(Loader* aLoader,
                 const nsSubstring& aTitle,
                 nsIURI* aURI,
                 nsCSSStyleSheet* aSheet,
                 nsIStyleSheetLinkingElement* aOwningElement,
                 bool aIsAlternate,
                 nsICSSLoaderObserver* aObserver,
                 nsIPrincipal* aLoaderPrincipal);
   // Data for loading a sheet linked from an @import rule
   SheetLoadData(Loader* aLoader,
                 nsIURI* aURI,
                 nsCSSStyleSheet* aSheet,
                 SheetLoadData* aParentData,
                 nsICSSLoaderObserver* aObserver,
                 nsIPrincipal* aLoaderPrincipal);
   // Data for loading a non-document sheet
   SheetLoadData(Loader* aLoader,
                 nsIURI* aURI,
                 nsCSSStyleSheet* aSheet,
                 bool aSyncLoad,
                 bool aAllowUnsafeRules,
                 bool aUseSystemPrincipal,
                 const nsCString& aCharset,
                 nsICSSLoaderObserver* aObserver,
                 nsIPrincipal* aLoaderPrincipal);
   already_AddRefed<nsIURI> GetReferrerURI();
   void ScheduleLoadEventIfNeeded(nsresult aStatus);
   NS_DECL_ISUPPORTS
   NS_DECL_NSIRUNNABLE
   NS_DECL_NSITHREADOBSERVER
   NS_DECL_NSIUNICHARSTREAMLOADEROBSERVER
   // Hold a ref to the CSSLoader so we can call back to it to let it
   // know the load finished
   Loader*                    mLoader; // strong ref
   // Title needed to pull datas out of the pending datas table when
   // the preferred title is changed
   nsString                   mTitle;
   // Charset we decided to use for the sheet
   nsCString                  mCharset;
   // URI we're loading.  Null for inline sheets
   nsCOMPtr<nsIURI>           mURI;
   // Should be 1 for non-inline sheets.
   uint32_t                   mLineNumber;
   // The sheet we're loading data for
   nsRefPtr<nsCSSStyleSheet>  mSheet;
   // Linked list of datas for the same URI as us
   SheetLoadData*             mNext;  // strong ref
   // Load data for the sheet that @import-ed us if we were @import-ed
   // during the parse
   SheetLoadData*             mParentData;  // strong ref
   // Number of sheets we @import-ed that are still loading
   uint32_t                   mPendingChildren;
   // mSyncLoad is true when the load needs to be synchronous -- right
   // now only for LoadSheetSync and children of sync loads.
   bool                       mSyncLoad : 1;
   // mIsNonDocumentSheet is true if the load was triggered by LoadSheetSync or
   // LoadSheet or an @import from such a sheet.  Non-document sheet loads can
   // proceed even if we have no document.
   bool                       mIsNonDocumentSheet : 1;
   // mIsLoading is true from the moment we are placed in the loader's
   // "loading datas" table (right after the async channel is opened)
   // to the moment we are removed from said table (due to the load
   // completing or being cancelled).
   bool                       mIsLoading : 1;
   // mIsCancelled is set to true when a sheet load is stopped by
   // Stop() or StopLoadingSheet() (which was removed in Bug 556446).
   // SheetLoadData::OnStreamComplete() checks this to avoid parsing
   // sheets that have been cancelled and such.
   bool                       mIsCancelled : 1;
   // mMustNotify is true if the load data is being loaded async and
   // the original function call that started the load has returned.
   // This applies only to observer notifications; load/error events
   // are fired for any SheetLoadData that has a non-null
   // mOwningElement.
   bool                       mMustNotify : 1;
   // mWasAlternate is true if the sheet was an alternate when the load data was
   // created.
   bool                       mWasAlternate : 1;
   // mAllowUnsafeRules is true if we should allow unsafe rules to be parsed
   // in the loaded sheet.
   bool                       mAllowUnsafeRules : 1;
   // mUseSystemPrincipal is true if the system principal should be used for
   // this sheet, no matter what the channel principal is.  Only true for sync
   // loads.
   bool                       mUseSystemPrincipal : 1;
   // If true, this SheetLoadData is being used as a way to handle
   // async observer notification for an already-complete sheet.
   bool                       mSheetAlreadyComplete : 1;
   // This is the element that imported the sheet.  Needed to get the
   // charset set on it and to fire load/error events.
   nsCOMPtr<nsIStyleSheetLinkingElement> mOwningElement;
   // The observer that wishes to be notified of load completion
   nsCOMPtr<nsICSSLoaderObserver>        mObserver;
   // The principal that identifies who started loading us.
   nsCOMPtr<nsIPrincipal>                mLoaderPrincipal;
   // The charset to use if the transport and sheet don't indicate one.
   // May be empty.  Must be empty if mOwningElement is non-null.
   nsCString                             mCharsetHint;
   // The status our load ended up with; this determines whether we
   // should fire error events or load events.  This gets initialized
   // by ScheduleLoadEventIfNeeded, and is only used after that has
   // been called.
   nsresult                              mStatus;
 private:
   void FireLoadEvent(nsIThreadInternal* aThread);
 };
 #ifdef MOZ_LOGGING
 // #define FORCE_PR_LOG /* Allow logging in the release build */
 #endif /* MOZ_LOGGING */
 #include "prlog.h"
 #ifdef PR_LOGGING
 static PRLogModuleInfo *
 GetLoaderLog()
 {
   static PRLogModuleInfo *sLog;
   if (!sLog)
     sLog = PR_NewLogModule("nsCSSLoader");
   return sLog;
 }
 #endif /* PR_LOGGING */
 #define LOG_FORCE(args) PR_LOG(GetLoaderLog(), PR_LOG_ALWAYS, args)
 #define LOG_ERROR(args) PR_LOG(GetLoaderLog(), PR_LOG_ERROR, args)
 #define LOG_WARN(args) PR_LOG(GetLoaderLog(), PR_LOG_WARNING, args)
 #define LOG_DEBUG(args) PR_LOG(GetLoaderLog(), PR_LOG_DEBUG, args)
 #define LOG(args) LOG_DEBUG(args)
 #define LOG_FORCE_ENABLED() PR_LOG_TEST(GetLoaderLog(), PR_LOG_ALWAYS)
 #define LOG_ERROR_ENABLED() PR_LOG_TEST(GetLoaderLog(), PR_LOG_ERROR)
 #define LOG_WARN_ENABLED() PR_LOG_TEST(GetLoaderLog(), PR_LOG_WARNING)
 #define LOG_DEBUG_ENABLED() PR_LOG_TEST(GetLoaderLog(), PR_LOG_DEBUG)
 #define LOG_ENABLED() LOG_DEBUG_ENABLED()
 #ifdef PR_LOGGING
 #define LOG_URI(format, uri)                        \
   PR_BEGIN_MACRO                                    \
     NS_ASSERTION(uri, "Logging null uri");          \
     if (LOG_ENABLED()) {                            \
       nsAutoCString _logURISpec;                    \
       uri->GetSpec(_logURISpec);                    \
       LOG((format, _logURISpec.get()));             \
     }                                               \
   PR_END_MACRO
 #else // PR_LOGGING
 #define LOG_URI(format, uri)
 #endif // PR_LOGGING
 // And some convenience strings...
 #ifdef PR_LOGGING
 static const char* const gStateStrings[] = {
   "eSheetStateUnknown",
   "eSheetNeedsParser",
   "eSheetPending",
   "eSheetLoading",
   "eSheetComplete"
 };
 #endif
 /********************************
  * SheetLoadData implementation *
  ********************************/
 NS_IMPL_ISUPPORTS(SheetLoadData, nsIUnicharStreamLoaderObserver, nsIRunnable,
                   nsIThreadObserver)
 SheetLoadData::SheetLoadData(Loader* aLoader,
                              const nsSubstring& aTitle,
                              nsIURI* aURI,
                              nsCSSStyleSheet* aSheet,
                              nsIStyleSheetLinkingElement* aOwningElement,
                              bool aIsAlternate,
                              nsICSSLoaderObserver* aObserver,
                              nsIPrincipal* aLoaderPrincipal)
   : mLoader(aLoader),
     mTitle(aTitle),
     mURI(aURI),
     mLineNumber(1),
     mSheet(aSheet),
     mNext(nullptr),
     mParentData(nullptr),
     mPendingChildren(0),
     mSyncLoad(false),
     mIsNonDocumentSheet(false),
     mIsLoading(false),
     mIsCancelled(false),
     mMustNotify(false),
     mWasAlternate(aIsAlternate),
     mAllowUnsafeRules(false),
     mUseSystemPrincipal(false),
     mSheetAlreadyComplete(false),
     mOwningElement(aOwningElement),
     mObserver(aObserver),
     mLoaderPrincipal(aLoaderPrincipal)
 {
   NS_PRECONDITION(mLoader, "Must have a loader!");
   NS_ADDREF(mLoader);
 }
 SheetLoadData::SheetLoadData(Loader* aLoader,
                              nsIURI* aURI,
                              nsCSSStyleSheet* aSheet,
                              SheetLoadData* aParentData,
                              nsICSSLoaderObserver* aObserver,
                              nsIPrincipal* aLoaderPrincipal)
   : mLoader(aLoader),
     mURI(aURI),
     mLineNumber(1),
     mSheet(aSheet),
     mNext(nullptr),
     mParentData(aParentData),
     mPendingChildren(0),
     mSyncLoad(false),
     mIsNonDocumentSheet(false),
     mIsLoading(false),
     mIsCancelled(false),
     mMustNotify(false),
     mWasAlternate(false),
     mAllowUnsafeRules(false),
     mUseSystemPrincipal(false),
     mSheetAlreadyComplete(false),
     mOwningElement(nullptr),
     mObserver(aObserver),
     mLoaderPrincipal(aLoaderPrincipal)
 {
   NS_PRECONDITION(mLoader, "Must have a loader!");
   NS_ADDREF(mLoader);
   if (mParentData) {
     NS_ADDREF(mParentData);
     mSyncLoad = mParentData->mSyncLoad;
     mIsNonDocumentSheet = mParentData->mIsNonDocumentSheet;
     mAllowUnsafeRules = mParentData->mAllowUnsafeRules;
     mUseSystemPrincipal = mParentData->mUseSystemPrincipal;
     ++(mParentData->mPendingChildren);
   }
   NS_POSTCONDITION(!mUseSystemPrincipal || mSyncLoad,
                    "Shouldn't use system principal for async loads");
 }
 SheetLoadData::SheetLoadData(Loader* aLoader,
                              nsIURI* aURI,
                              nsCSSStyleSheet* aSheet,
                              bool aSyncLoad,
                              bool aAllowUnsafeRules,
                              bool aUseSystemPrincipal,
                              const nsCString& aCharset,
                              nsICSSLoaderObserver* aObserver,
                              nsIPrincipal* aLoaderPrincipal)
   : mLoader(aLoader),
     mURI(aURI),
     mLineNumber(1),
     mSheet(aSheet),
     mNext(nullptr),
     mParentData(nullptr),
     mPendingChildren(0),
     mSyncLoad(aSyncLoad),
     mIsNonDocumentSheet(true),
     mIsLoading(false),
     mIsCancelled(false),
     mMustNotify(false),
     mWasAlternate(false),
     mAllowUnsafeRules(aAllowUnsafeRules),
     mUseSystemPrincipal(aUseSystemPrincipal),
     mSheetAlreadyComplete(false),
     mOwningElement(nullptr),
     mObserver(aObserver),
     mLoaderPrincipal(aLoaderPrincipal),
     mCharsetHint(aCharset)
 {
   NS_PRECONDITION(mLoader, "Must have a loader!");
   NS_ADDREF(mLoader);
   NS_POSTCONDITION(!mUseSystemPrincipal || mSyncLoad,
                    "Shouldn't use system principal for async loads");
 }
 SheetLoadData::~SheetLoadData()
 {
   NS_RELEASE(mLoader);
   NS_IF_RELEASE(mParentData);
   NS_IF_RELEASE(mNext);
 }
 NS_IMETHODIMP
 SheetLoadData::Run()
 {
   mLoader->HandleLoadEvent(this);
   return NS_OK;
 }
 NS_IMETHODIMP
 SheetLoadData::OnDispatchedEvent(nsIThreadInternal* aThread)
 {
   return NS_OK;
 }
 NS_IMETHODIMP
 SheetLoadData::OnProcessNextEvent(nsIThreadInternal* aThread,
                                   bool aMayWait,
                                   uint32_t aRecursionDepth)
 {
   // We want to fire our load even before or after event processing,
   // whichever comes first.
   FireLoadEvent(aThread);
   return NS_OK;
 }
 NS_IMETHODIMP
 SheetLoadData::AfterProcessNextEvent(nsIThreadInternal* aThread,
                                      uint32_t aRecursionDepth,
                                      bool aEventWasProcessed)
 {
   // We want to fire our load even before or after event processing,
   // whichever comes first.
   FireLoadEvent(aThread);
   return NS_OK;
 }
 void
 SheetLoadData::FireLoadEvent(nsIThreadInternal* aThread)
 {
   // First remove ourselves as a thread observer.  But we need to keep
   // ourselves alive while doing that!
   nsRefPtr<SheetLoadData> kungFuDeathGrip(this);
   aThread->RemoveObserver(this);
   // Now fire the event
   nsCOMPtr<nsINode> node = do_QueryInterface(mOwningElement);
   NS_ASSERTION(node, "How did that happen???");
   nsContentUtils::DispatchTrustedEvent(node->OwnerDoc(),
                                        node,
                                        NS_SUCCEEDED(mStatus) ?
                                          NS_LITERAL_STRING("load") :
                                          NS_LITERAL_STRING("error"),
                                        false, false);
   // And unblock onload
   if (mLoader->mDocument) {
     mLoader->mDocument->UnblockOnload(true);
   }
 }
 void
 SheetLoadData::ScheduleLoadEventIfNeeded(nsresult aStatus)
 {
   if (!mOwningElement) {
     return;
   }
   mStatus = aStatus;
   nsCOMPtr<nsIThread> thread = do_GetMainThread();
   nsCOMPtr<nsIThreadInternal> internalThread = do_QueryInterface(thread);
   if (NS_SUCCEEDED(internalThread->AddObserver(this))) {
     // Make sure to block onload here
     if (mLoader->mDocument) {
       mLoader->mDocument->BlockOnload();
     }
   }
 }
 /*************************
  * Loader Implementation *
  *************************/
 Loader::Loader(void)
   : mDocument(nullptr)
   , mDatasToNotifyOn(0)
   , mCompatMode(eCompatibility_FullStandards)
   , mEnabled(true)
 #ifdef DEBUG
   , mSyncCallback(false)
 #endif
 {
 }
 Loader::Loader(nsIDocument* aDocument)
   : mDocument(aDocument)
   , mDatasToNotifyOn(0)
   , mCompatMode(eCompatibility_FullStandards)
   , mEnabled(true)
 #ifdef DEBUG
   , mSyncCallback(false)
 #endif
 {
   // We can just use the preferred set, since there are no sheets in the
   // document yet (if there are, how did they get there? _we_ load the sheets!)
   // and hence the selected set makes no sense at this time.
   nsCOMPtr<nsIDOMDocument> domDoc = do_QueryInterface(mDocument);
   if (domDoc) {
     domDoc->GetPreferredStyleSheetSet(mPreferredSheet);
   }
 }
 Loader::~Loader()
 {
   NS_ASSERTION(!mSheets || mSheets->mLoadingDatas.Count() == 0,
                "How did we get destroyed when there are loading data?");
   NS_ASSERTION(!mSheets || mSheets->mPendingDatas.Count() == 0,
                "How did we get destroyed when there are pending data?");
   // Note: no real need to revoke our stylesheet loaded events -- they
   // hold strong references to us, so if we're going away that means
   // they're all done.
 }
 void
 Loader::DropDocumentReference(void)
 {
   mDocument = nullptr;
   // Flush out pending datas just so we don't leak by accident.  These
   // loads should short-circuit through the mDocument check in
   // LoadSheet and just end up in SheetComplete immediately
   if (mSheets) {
     StartAlternateLoads();
   }
 }
 static PLDHashOperator
 CollectNonAlternates(URIPrincipalAndCORSModeHashKey *aKey,
                      SheetLoadData* &aData,
                      void* aClosure)
 {
   NS_PRECONDITION(aData, "Must have a data");
   NS_PRECONDITION(aClosure, "Must have an array");
   // Note that we don't want to affect what the selected style set is,
   // so use true for aHasAlternateRel.
   if (aData->mLoader->IsAlternate(aData->mTitle, true)) {
     return PL_DHASH_NEXT;
   }
   static_cast<Loader::LoadDataArray*>(aClosure)->AppendElement(aData);
   return PL_DHASH_REMOVE;
 }
 nsresult
 Loader::SetPreferredSheet(const nsAString& aTitle)
 {
 #ifdef DEBUG
   nsCOMPtr<nsIDOMDocument> doc = do_QueryInterface(mDocument);
   if (doc) {
     nsAutoString currentPreferred;
     doc->GetLastStyleSheetSet(currentPreferred);
     if (DOMStringIsNull(currentPreferred)) {
       doc->GetPreferredStyleSheetSet(currentPreferred);
     }
     NS_ASSERTION(currentPreferred.Equals(aTitle),
                  "Unexpected argument to SetPreferredSheet");
   }
 #endif
   mPreferredSheet = aTitle;
   // start any pending alternates that aren't alternates anymore
   if (mSheets) {
     LoadDataArray arr(mSheets->mPendingDatas.Count());
     mSheets->mPendingDatas.Enumerate(CollectNonAlternates, &arr);
     mDatasToNotifyOn += arr.Length();
     for (uint32_t i = 0; i < arr.Length(); ++i) {
       --mDatasToNotifyOn;
       LoadSheet(arr[i], eSheetNeedsParser);
     }
   }
   return NS_OK;
 }
 static const char kCharsetSym[] = "@charset \"";
 static bool GetCharsetFromData(const char* aStyleSheetData,
                                uint32_t aDataLength,
                                nsACString& aCharset)
 {
   aCharset.Truncate();
   if (aDataLength <= sizeof(kCharsetSym) - 1)
     return false;
   if (strncmp(aStyleSheetData,
               kCharsetSym,
               sizeof(kCharsetSym) - 1)) {
     return false;
   }
   for (uint32_t i = sizeof(kCharsetSym) - 1; i < aDataLength; ++i) {
     char c = aStyleSheetData[i];
     if (c == '"') {
       ++i;
       if (i < aDataLength && aStyleSheetData[i] == ';') {
         return true;
       }
       // fail
       break;
     }
     aCharset.Append(c);
   }
   // Did not see end quote or semicolon
   aCharset.Truncate();
   return false;
 }
 NS_IMETHODIMP
 SheetLoadData::OnDetermineCharset(nsIUnicharStreamLoader* aLoader,
                                   nsISupports* aContext,
                                   nsACString const& aSegment,
                                   nsACString& aCharset)
 {
   NS_PRECONDITION(!mOwningElement || mCharsetHint.IsEmpty(),
                   "Can't have element _and_ charset hint");
   LOG_URI("SheetLoadData::OnDetermineCharset for '%s'", mURI);
   // The precedence is (per CSS3 Syntax 2012-11-08 ED):
   // BOM
   // Channel
   // @charset rule
   // charset attribute on the referrer
   // encoding of the referrer
   // UTF-8
   aCharset.Truncate();
   if (nsContentUtils::CheckForBOM((const unsigned char*)aSegment.BeginReading(),
                                   aSegment.Length(),
                                   aCharset)) {
     // aCharset is now either "UTF-16BE", "UTF-16BE" or "UTF-8"
     // which will swallow the BOM.
     mCharset.Assign(aCharset);
 #ifdef PR_LOGGING
     LOG(("  Setting from BOM to: %s", PromiseFlatCString(aCharset).get()));
 #endif
     return NS_OK;
   }
   nsCOMPtr<nsIChannel> channel;
   nsAutoCString specified;
   aLoader->GetChannel(getter_AddRefs(channel));
   if (channel) {
     channel->GetContentCharset(specified);
     if (EncodingUtils::FindEncodingForLabel(specified, aCharset)) {
       mCharset.Assign(aCharset);
 #ifdef PR_LOGGING
       LOG(("  Setting from HTTP to: %s", PromiseFlatCString(aCharset).get()));
 #endif
       return NS_OK;
     }
   }
   if (GetCharsetFromData(aSegment.BeginReading(),
                          aSegment.Length(),
                          specified)) {
     if (EncodingUtils::FindEncodingForLabel(specified, aCharset)) {
       // FindEncodingForLabel currently never returns UTF-16LE but will
       // probably change to never return UTF-16 instead, so check both here
       // to avoid relying on the exact behavior.
       if (aCharset.EqualsLiteral("UTF-16") ||
           aCharset.EqualsLiteral("UTF-16BE") ||
           aCharset.EqualsLiteral("UTF-16LE")) {
         // Be consistent with HTML <meta> handling in face of impossibility.
         // When the @charset rule itself evidently was not UTF-16-encoded,
         // it saying UTF-16 has to be a lie.
         aCharset.AssignLiteral("UTF-8");
       }
       mCharset.Assign(aCharset);
 #ifdef PR_LOGGING
       LOG(("  Setting from @charset rule to: %s",
           PromiseFlatCString(aCharset).get()));
 #endif
       return NS_OK;
     }
   }
   // Now try the charset on the <link> or processing instruction
   // that loaded us
   if (mOwningElement) {
     nsAutoString specified16;
     mOwningElement->GetCharset(specified16);
     if (EncodingUtils::FindEncodingForLabel(specified16, aCharset)) {
       mCharset.Assign(aCharset);
 #ifdef PR_LOGGING
       LOG(("  Setting from charset attribute to: %s",
           PromiseFlatCString(aCharset).get()));
 #endif
       return NS_OK;
     }
   }
   // In the preload case, the value of the charset attribute on <link> comes
   // in via mCharsetHint instead.
   if (EncodingUtils::FindEncodingForLabel(mCharsetHint, aCharset)) {
     mCharset.Assign(aCharset);
 #ifdef PR_LOGGING
       LOG(("  Setting from charset attribute (preload case) to: %s",
           PromiseFlatCString(aCharset).get()));
 #endif
     return NS_OK;
   }
   // Try charset from the parent stylesheet.
   if (mParentData) {
     aCharset = mParentData->mCharset;
     if (!aCharset.IsEmpty()) {
       mCharset.Assign(aCharset);
 #ifdef PR_LOGGING
       LOG(("  Setting from parent sheet to: %s",
           PromiseFlatCString(aCharset).get()));
 #endif
       return NS_OK;
     }
   }
   if (mLoader->mDocument) {
     // no useful data on charset.  Try the document charset.
     aCharset = mLoader->mDocument->GetDocumentCharacterSet();
     MOZ_ASSERT(!aCharset.IsEmpty());
     mCharset.Assign(aCharset);
 #ifdef PR_LOGGING
     LOG(("  Setting from document to: %s", PromiseFlatCString(aCharset).get()));
 #endif
     return NS_OK;
   }
   aCharset.AssignLiteral("UTF-8");
   mCharset = aCharset;
 #ifdef PR_LOGGING
   LOG(("  Setting from default to: %s", PromiseFlatCString(aCharset).get()));
 #endif
   return NS_OK;
 }
 already_AddRefed<nsIURI>
 SheetLoadData::GetReferrerURI()
 {
   nsCOMPtr<nsIURI> uri;
   if (mParentData)
     uri = mParentData->mSheet->GetSheetURI();
   if (!uri && mLoader->mDocument)
     uri = mLoader->mDocument->GetDocumentURI();
   return uri.forget();
 }
 /*
  * Here we need to check that the load did not give us an http error
  * page and check the mimetype on the channel to make sure we're not
  * loading non-text/css data in standards mode.
  */
 NS_IMETHODIMP
 SheetLoadData::OnStreamComplete(nsIUnicharStreamLoader* aLoader,
                                 nsISupports* aContext,
                                 nsresult aStatus,
                                 const nsAString& aBuffer)
 {
   LOG(("SheetLoadData::OnStreamComplete"));
   NS_ASSERTION(!mLoader->mSyncCallback, "Synchronous callback from necko");
   if (mIsCancelled) {
     // Just return.  Don't call SheetComplete -- it's already been
     // called and calling it again will lead to an extra NS_RELEASE on
     // this data and a likely crash.
     return NS_OK;
   }
   if (!mLoader->mDocument && !mIsNonDocumentSheet) {
     // Sorry, we don't care about this load anymore
     LOG_WARN(("  No document and not non-document sheet; dropping load"));
     mLoader->SheetComplete(this, NS_BINDING_ABORTED);
     return NS_OK;
   }
   if (NS_FAILED(aStatus)) {
     LOG_WARN(("  Load failed: status 0x%x", aStatus));
     mLoader->SheetComplete(this, aStatus);
     return NS_OK;
   }
   nsCOMPtr<nsIChannel> channel;
   nsresult result = aLoader->GetChannel(getter_AddRefs(channel));
   if (NS_FAILED(result)) {
     LOG_WARN(("  No channel from loader"));
     mLoader->SheetComplete(this, result);
     return NS_OK;
   }
   nsCOMPtr<nsIURI> originalURI;
   channel->GetOriginalURI(getter_AddRefs(originalURI));
   // If the channel's original URI is "chrome:", we want that, since
   // the observer code in nsXULPrototypeCache depends on chrome stylesheets
   // having a chrome URI.  (Whether or not chrome stylesheets come through
   // this codepath seems nondeterministic.)
   // Otherwise we want the potentially-HTTP-redirected URI.
   nsCOMPtr<nsIURI> channelURI;
   NS_GetFinalChannelURI(channel, getter_AddRefs(channelURI));
   if (!channelURI || !originalURI) {
     NS_ERROR("Someone just violated the nsIRequest contract");
     LOG_WARN(("  Channel without a URI.  Bad!"));
     mLoader->SheetComplete(this, NS_ERROR_UNEXPECTED);
     return NS_OK;
   }
   nsCOMPtr<nsIPrincipal> principal;
   nsIScriptSecurityManager* secMan = nsContentUtils::GetSecurityManager();
   result = NS_ERROR_NOT_AVAILABLE;
   if (secMan) {  // Could be null if we already shut down
     if (mUseSystemPrincipal) {
       result = secMan->GetSystemPrincipal(getter_AddRefs(principal));
     } else {
       result = secMan->GetChannelPrincipal(channel, getter_AddRefs(principal));
     }
   }
   if (NS_FAILED(result)) {
     LOG_WARN(("  Couldn't get principal"));
     mLoader->SheetComplete(this, result);
     return NS_OK;
   }
   mSheet->SetPrincipal(principal);
   // If it's an HTTP channel, we want to make sure this is not an
   // error document we got.
   nsCOMPtr<nsIHttpChannel> httpChannel(do_QueryInterface(channel));
   if (httpChannel) {
     bool requestSucceeded;
     result = httpChannel->GetRequestSucceeded(&requestSucceeded);
     if (NS_SUCCEEDED(result) && !requestSucceeded) {
       LOG(("  Load returned an error page"));
       mLoader->SheetComplete(this, NS_ERROR_NOT_AVAILABLE);
       return NS_OK;
     }
   }
   nsAutoCString contentType;
   if (channel) {
     channel->GetContentType(contentType);
   }
   // In standards mode, a style sheet must have one of these MIME
   // types to be processed at all.  In quirks mode, we accept any
   // MIME type, but only if the style sheet is same-origin with the
   // requesting document or parent sheet.  See bug 524223.
   bool validType = contentType.EqualsLiteral("text/css") ||
     contentType.EqualsLiteral(UNKNOWN_CONTENT_TYPE) ||
     contentType.IsEmpty();
   if (!validType) {
     const char *errorMessage;
     uint32_t errorFlag;
     bool sameOrigin = true;
     if (mLoaderPrincipal) {
       bool subsumed;
       result = mLoaderPrincipal->Subsumes(principal, &subsumed);
       if (NS_FAILED(result) || !subsumed) {
         sameOrigin = false;
       }
     }
     if (sameOrigin && mLoader->mCompatMode == eCompatibility_NavQuirks) {
       errorMessage = "MimeNotCssWarn";
       errorFlag = nsIScriptError::warningFlag;
     } else {
       errorMessage = "MimeNotCss";
       errorFlag = nsIScriptError::errorFlag;
     }
     nsAutoCString spec;
     channelURI->GetSpec(spec);
     const nsAFlatString& specUTF16 = NS_ConvertUTF8toUTF16(spec);
     const nsAFlatString& ctypeUTF16 = NS_ConvertASCIItoUTF16(contentType);
     const char16_t *strings[] = { specUTF16.get(), ctypeUTF16.get() };
     nsCOMPtr<nsIURI> referrer = GetReferrerURI();
     nsContentUtils::ReportToConsole(errorFlag,
                                     NS_LITERAL_CSTRING("CSS Loader"),
                                     mLoader->mDocument,
                                     nsContentUtils::eCSS_PROPERTIES,
                                     errorMessage,
                                     strings, ArrayLength(strings),
                                     referrer);
     if (errorFlag == nsIScriptError::errorFlag) {
       LOG_WARN(("  Ignoring sheet with improper MIME type %s",
                 contentType.get()));
       mLoader->SheetComplete(this, NS_ERROR_NOT_AVAILABLE);
       return NS_OK;
     }
   }
   // Enough to set the URIs on mSheet, since any sibling datas we have share
   // the same mInner as mSheet and will thus get the same URI.
   mSheet->SetURIs(channelURI, originalURI, channelURI);
   bool completed;
   result = mLoader->ParseSheet(aBuffer, this, completed);
   NS_ASSERTION(completed || !mSyncLoad, "sync load did not complete");
   return result;
 }
 bool
 Loader::IsAlternate(const nsAString& aTitle, bool aHasAlternateRel)
 {
   // A sheet is alternate if it has a nonempty title that doesn't match the
   // currently selected style set.  But if there _is_ no currently selected
   // style set, the sheet wasn't marked as an alternate explicitly, and aTitle
   // is nonempty, we should select the style set corresponding to aTitle, since
   // that's a preferred sheet.
   if (aTitle.IsEmpty()) {
     return false;
   }
   if (!aHasAlternateRel && mDocument && mPreferredSheet.IsEmpty()) {
     // There's no preferred set yet, and we now have a sheet with a title.
     // Make that be the preferred set.
     mDocument->SetHeaderData(nsGkAtoms::headerDefaultStyle, aTitle);
     // We're definitely not an alternate
     return false;
   }
   return !aTitle.Equals(mPreferredSheet);
 }
 /* static */ PLDHashOperator
 Loader::RemoveEntriesWithURI(URIPrincipalAndCORSModeHashKey* aKey,
                              nsRefPtr<nsCSSStyleSheet> &aSheet,
                              void* aUserData)
 {
   nsIURI* obsoleteURI = static_cast<nsIURI*>(aUserData);
   nsIURI* sheetURI = aKey->GetURI();
   bool areEqual;
   nsresult rv = sheetURI->Equals(obsoleteURI, &areEqual);
   if (NS_SUCCEEDED(rv) && areEqual) {
     return PL_DHASH_REMOVE;
   }
   return PL_DHASH_NEXT;
 }
 nsresult
 Loader::ObsoleteSheet(nsIURI* aURI)
 {
   if (!mSheets) {
     return NS_OK;
   }
   if (!aURI) {
     return NS_ERROR_INVALID_ARG;
   }
   mSheets->mCompleteSheets.Enumerate(RemoveEntriesWithURI, aURI);
   return NS_OK;
 }
 /**
  * CheckLoadAllowed will return success if the load is allowed,
  * failure otherwise.
  *
  * @param aSourcePrincipal the principal of the node or document or parent
  *                         sheet loading the sheet
  * @param aTargetURI the uri of the sheet to be loaded
  * @param aContext the node owning the sheet.  This is the element or document
  *                 owning the stylesheet (possibly indirectly, for child sheets)
  */
 nsresult
 Loader::CheckLoadAllowed(nsIPrincipal* aSourcePrincipal,
                          nsIURI* aTargetURI,
                          nsISupports* aContext)
 {
   LOG(("css::Loader::CheckLoadAllowed"));
   nsresult rv;
   if (aSourcePrincipal) {
     // Check with the security manager
     nsIScriptSecurityManager *secMan = nsContentUtils::GetSecurityManager();
     rv =
       secMan->CheckLoadURIWithPrincipal(aSourcePrincipal, aTargetURI,
                                         nsIScriptSecurityManager::ALLOW_CHROME);
     if (NS_FAILED(rv)) { // failure is normal here; don't warn
       return rv;
     }
     LOG(("  Passed security check"));
     // Check with content policy
     int16_t shouldLoad = nsIContentPolicy::ACCEPT;
     rv = NS_CheckContentLoadPolicy(nsIContentPolicy::TYPE_STYLESHEET,
                                    aTargetURI,
                                    aSourcePrincipal,
                                    aContext,
                                    NS_LITERAL_CSTRING("text/css"),
                                    nullptr,                     //extra param
                                    &shouldLoad,
                                    nsContentUtils::GetContentPolicy(),
                                    nsContentUtils::GetSecurityManager());
     if (NS_FAILED(rv) || NS_CP_REJECTED(shouldLoad)) {
       LOG(("  Load blocked by content policy"));
       return NS_ERROR_CONTENT_BLOCKED;
     }
   }
   return NS_OK;
 }
 /**
  * CreateSheet() creates an nsCSSStyleSheet object for the given URI,
  * if any.  If there is no URI given, we just create a new style sheet
  * object.  Otherwise, we check for an existing style sheet object for
  * that uri in various caches and clone it if we find it.  Cloned
  * sheets will have the title/media/enabled state of the sheet they
  * are clones off; make sure to call PrepareSheet() on the result of
  * CreateSheet().
  */
 nsresult
 Loader::CreateSheet(nsIURI* aURI,
                     nsIContent* aLinkingContent,
                     nsIPrincipal* aLoaderPrincipal,
                     CORSMode aCORSMode,
                     bool aSyncLoad,
                     bool aHasAlternateRel,
                     const nsAString& aTitle,
                     StyleSheetState& aSheetState,
                     bool *aIsAlternate,
                     nsCSSStyleSheet** aSheet)
 {
   LOG(("css::Loader::CreateSheet"));
   NS_PRECONDITION(aSheet, "Null out param!");
   if (!mSheets) {
     mSheets = new Sheets();
   }
   *aSheet = nullptr;
   aSheetState = eSheetStateUnknown;
   // Check the alternate state before doing anything else, because it
   // can mess with our hashtables.
   *aIsAlternate = IsAlternate(aTitle, aHasAlternateRel);
   if (aURI) {
     aSheetState = eSheetComplete;
     nsRefPtr<nsCSSStyleSheet> sheet;
     // First, the XUL cache
 #ifdef MOZ_XUL
     if (IsChromeURI(aURI)) {
       nsXULPrototypeCache* cache = nsXULPrototypeCache::GetInstance();
       if (cache) {
         if (cache->IsEnabled()) {
           sheet = cache->GetStyleSheet(aURI);
           LOG(("  From XUL cache: %p", sheet.get()));
         }
       }
     }
 #endif
     bool fromCompleteSheets = false;
     if (!sheet) {
       // Then our per-document complete sheets.
       URIPrincipalAndCORSModeHashKey key(aURI, aLoaderPrincipal, aCORSMode);
       mSheets->mCompleteSheets.Get(&key, getter_AddRefs(sheet));
       LOG(("  From completed: %p", sheet.get()));
       fromCompleteSheets = !!sheet;
     }
     if (sheet) {
       // This sheet came from the XUL cache or our per-document hashtable; it
       // better be a complete sheet.
       NS_ASSERTION(sheet->IsComplete(),
                    "Sheet thinks it's not complete while we think it is");
       // Make sure it hasn't been modified; if it has, we can't use it
       if (sheet->IsModified()) {
         LOG(("  Not cloning completed sheet %p because it's been modified",
              sheet.get()));
         sheet = nullptr;
         fromCompleteSheets = false;
       }
     }
     // Then loading sheets
     if (!sheet && !aSyncLoad) {
       aSheetState = eSheetLoading;
       SheetLoadData* loadData = nullptr;
       URIPrincipalAndCORSModeHashKey key(aURI, aLoaderPrincipal, aCORSMode);
       mSheets->mLoadingDatas.Get(&key, &loadData);
       if (loadData) {
         sheet = loadData->mSheet;
         LOG(("  From loading: %p", sheet.get()));
 #ifdef DEBUG
         bool debugEqual;
         NS_ASSERTION((!aLoaderPrincipal && !loadData->mLoaderPrincipal) ||
                      (aLoaderPrincipal && loadData->mLoaderPrincipal &&
                       NS_SUCCEEDED(aLoaderPrincipal->
                                    Equals(loadData->mLoaderPrincipal,
                                           &debugEqual)) && debugEqual),
                      "Principals should be the same");
 #endif
       }
       // Then alternate sheets
       if (!sheet) {
         aSheetState = eSheetPending;
         loadData = nullptr;
         mSheets->mPendingDatas.Get(&key, &loadData);
         if (loadData) {
           sheet = loadData->mSheet;
           LOG(("  From pending: %p", sheet.get()));
 #ifdef DEBUG
           bool debugEqual;
           NS_ASSERTION((!aLoaderPrincipal && !loadData->mLoaderPrincipal) ||
                        (aLoaderPrincipal && loadData->mLoaderPrincipal &&
                         NS_SUCCEEDED(aLoaderPrincipal->
                                      Equals(loadData->mLoaderPrincipal,
                                             &debugEqual)) && debugEqual),
                        "Principals should be the same");
 #endif
         }
       }
     }
     if (sheet) {
       // The sheet we have now should be either incomplete or unmodified
       NS_ASSERTION(!sheet->IsModified() || !sheet->IsComplete(),
                    "Unexpected modified complete sheet");
       NS_ASSERTION(sheet->IsComplete() || aSheetState != eSheetComplete,
                    "Sheet thinks it's not complete while we think it is");
       *aSheet = sheet->Clone(nullptr, nullptr, nullptr, nullptr).take();
       if (*aSheet && fromCompleteSheets &&
           !sheet->GetOwnerNode() && !sheet->GetParentSheet()) {
         // The sheet we're cloning isn't actually referenced by
         // anyone.  Replace it in the cache, so that if our CSSOM is
         // later modified we don't end up with two copies of our inner
         // hanging around.
         URIPrincipalAndCORSModeHashKey key(aURI, aLoaderPrincipal, aCORSMode);
         NS_ASSERTION((*aSheet)->IsComplete(),
                      "Should only be caching complete sheets");
         mSheets->mCompleteSheets.Put(&key, *aSheet);
       }
     }
   }
   if (!*aSheet) {
     aSheetState = eSheetNeedsParser;
     nsIURI *sheetURI;
     nsCOMPtr<nsIURI> baseURI;
     nsIURI* originalURI;
     if (!aURI) {
       // Inline style.  Use the document's base URL so that @import in
       // the inline sheet picks up the right base.
       NS_ASSERTION(aLinkingContent, "Inline stylesheet without linking content?");
       baseURI = aLinkingContent->GetBaseURI();
       sheetURI = aLinkingContent->GetDocument()->GetDocumentURI();
       originalURI = nullptr;
     } else {
       baseURI = aURI;
       sheetURI = aURI;
       originalURI = aURI;
     }
     nsRefPtr<nsCSSStyleSheet> sheet = new nsCSSStyleSheet(aCORSMode);
     sheet->SetURIs(sheetURI, originalURI, baseURI);
     sheet.forget(aSheet);
   }
   NS_ASSERTION(*aSheet, "We should have a sheet by now!");
   NS_ASSERTION(aSheetState != eSheetStateUnknown, "Have to set a state!");
   LOG(("  State: %s", gStateStrings[aSheetState]));
   return NS_OK;
 }
 /**
  * PrepareSheet() handles setting the media and title on the sheet, as
  * well as setting the enabled state based on the title and whether
  * the sheet had "alternate" in its rel.
  */
 void
 Loader::PrepareSheet(nsCSSStyleSheet* aSheet,
                      const nsSubstring& aTitle,
                      const nsSubstring& aMediaString,
                      nsMediaList* aMediaList,
                      Element* aScopeElement,
                      bool isAlternate)
 {
   NS_PRECONDITION(aSheet, "Must have a sheet!");
   nsRefPtr<nsMediaList> mediaList(aMediaList);
   if (!aMediaString.IsEmpty()) {
     NS_ASSERTION(!aMediaList,
                  "must not provide both aMediaString and aMediaList");
     mediaList = new nsMediaList();
     nsCSSParser mediumParser(this);
     // We have aMediaString only when linked from link elements, style
     // elements, or PIs, so pass true.
     mediumParser.ParseMediaList(aMediaString, nullptr, 0, mediaList, true);
   }
   aSheet->SetMedia(mediaList);
   aSheet->SetTitle(aTitle);
   aSheet->SetEnabled(! isAlternate);
   aSheet->SetScopeElement(aScopeElement);
 }
 /**
  * InsertSheetInDoc handles ordering of sheets in the document.  Here
  * we have two types of sheets -- those with linking elements and
  * those without.  The latter are loaded by Link: headers.
  * The following constraints are observed:
  * 1) Any sheet with a linking element comes after all sheets without
  *    linking elements
  * 2) Sheets without linking elements are inserted in the order in
  *    which the inserting requests come in, since all of these are
  *    inserted during header data processing in the content sink
  * 3) Sheets with linking elements are ordered based on document order
  *    as determined by CompareDocumentPosition.
  */
 nsresult
 Loader::InsertSheetInDoc(nsCSSStyleSheet* aSheet,
                          nsIContent* aLinkingContent,
                          nsIDocument* aDocument)
 {
   LOG(("css::Loader::InsertSheetInDoc"));
   NS_PRECONDITION(aSheet, "Nothing to insert");
   NS_PRECONDITION(aDocument, "Must have a document to insert into");
   // XXX Need to cancel pending sheet loads for this element, if any
   int32_t sheetCount = aDocument->GetNumberOfStyleSheets();
   /*
    * Start the walk at the _end_ of the list, since in the typical
    * case we'll just want to append anyway.  We want to break out of
    * the loop when insertionPoint points to just before the index we
    * want to insert at.  In other words, when we leave the loop
    * insertionPoint is the index of the stylesheet that immediately
    * precedes the one we're inserting.
    */
   int32_t insertionPoint;
   for (insertionPoint = sheetCount - 1; insertionPoint >= 0; --insertionPoint) {
     nsIStyleSheet *curSheet = aDocument->GetStyleSheetAt(insertionPoint);
     NS_ASSERTION(curSheet, "There must be a sheet here!");
     nsCOMPtr<nsIDOMStyleSheet> domSheet = do_QueryInterface(curSheet);
     NS_ASSERTION(domSheet, "All the \"normal\" sheets implement nsIDOMStyleSheet");
     nsCOMPtr<nsIDOMNode> sheetOwner;
     domSheet->GetOwnerNode(getter_AddRefs(sheetOwner));
     if (sheetOwner && !aLinkingContent) {
       // Keep moving; all sheets with a sheetOwner come after all
       // sheets without a linkingNode
       continue;
     }
     if (!sheetOwner) {
       // Aha!  The current sheet has no sheet owner, so we want to
       // insert after it no matter whether we have a linkingNode
       break;
     }
     nsCOMPtr<nsINode> sheetOwnerNode = do_QueryInterface(sheetOwner);
     NS_ASSERTION(aLinkingContent != sheetOwnerNode,
                  "Why do we still have our old sheet?");
     // Have to compare
     if (nsContentUtils::PositionIsBefore(sheetOwnerNode, aLinkingContent)) {
       // The current sheet comes before us, and it better be the first
       // such, because now we break
       break;
     }
   }
   ++insertionPoint; // adjust the index to the spot we want to insert in
   // XXX <meta> elements do not implement nsIStyleSheetLinkingElement;
   // need to fix this for them to be ordered correctly.
   nsCOMPtr<nsIStyleSheetLinkingElement>
     linkingElement = do_QueryInterface(aLinkingContent);
   if (linkingElement) {
     linkingElement->SetStyleSheet(aSheet); // This sets the ownerNode on the sheet
   }
   aDocument->BeginUpdate(UPDATE_STYLE);
   aDocument->InsertStyleSheetAt(aSheet, insertionPoint);
   aDocument->EndUpdate(UPDATE_STYLE);
   LOG(("  Inserting into document at position %d", insertionPoint));
   return NS_OK;
 }
 /**
  * InsertChildSheet handles ordering of @import-ed sheet in their
  * parent sheets.  Here we want to just insert based on order of the
  * @import rules that imported the sheets.  In theory we can't just
  * append to the end because the CSSOM can insert @import rules.  In
  * practice, we get the call to load the child sheet before the CSSOM
  * has finished inserting the @import rule, so we have no idea where
  * to put it anyway.  So just append for now.
  */
 nsresult
 Loader::InsertChildSheet(nsCSSStyleSheet* aSheet,
                          nsCSSStyleSheet* aParentSheet,
                          ImportRule* aParentRule)
 {
   LOG(("css::Loader::InsertChildSheet"));
   NS_PRECONDITION(aSheet, "Nothing to insert");
   NS_PRECONDITION(aParentSheet, "Need a parent to insert into");
   NS_PRECONDITION(aParentSheet, "How did we get imported?");
   // child sheets should always start out enabled, even if they got
   // cloned off of top-level sheets which were disabled
   aSheet->SetEnabled(true);
   aParentSheet->AppendStyleSheet(aSheet);
   aParentRule->SetSheet(aSheet); // This sets the ownerRule on the sheet
   LOG(("  Inserting into parent sheet"));
   //  LOG(("  Inserting into parent sheet at position %d", insertionPoint));
   return NS_OK;
 }
 /**
  * LoadSheet handles the actual load of a sheet.  If the load is
  * supposed to be synchronous it just opens a channel synchronously
  * using the given uri, wraps the resulting stream in a converter
  * stream and calls ParseSheet.  Otherwise it tries to look for an
  * existing load for this URI and piggyback on it.  Failing all that,
  * a new load is kicked off asynchronously.
  */
 nsresult
 Loader::LoadSheet(SheetLoadData* aLoadData, StyleSheetState aSheetState)
 {
   LOG(("css::Loader::LoadSheet"));
   NS_PRECONDITION(aLoadData, "Need a load data");
   NS_PRECONDITION(aLoadData->mURI, "Need a URI to load");
   NS_PRECONDITION(aLoadData->mSheet, "Need a sheet to load into");
   NS_PRECONDITION(aSheetState != eSheetComplete, "Why bother?");
   NS_PRECONDITION(!aLoadData->mUseSystemPrincipal || aLoadData->mSyncLoad,
                   "Shouldn't use system principal for async loads");
   NS_ASSERTION(mSheets, "mLoadingDatas should be initialized by now.");
   LOG_URI("  Load from: '%s'", aLoadData->mURI);
   nsresult rv = NS_OK;
   if (!mDocument && !aLoadData->mIsNonDocumentSheet) {
     // No point starting the load; just release all the data and such.
     LOG_WARN(("  No document and not non-document sheet; pre-dropping load"));
     SheetComplete(aLoadData, NS_BINDING_ABORTED);
     return NS_BINDING_ABORTED;
   }
   if (aLoadData->mSyncLoad) {
     LOG(("  Synchronous load"));
     NS_ASSERTION(!aLoadData->mObserver, "Observer for a sync load?");
     NS_ASSERTION(aSheetState == eSheetNeedsParser,
                  "Sync loads can't reuse existing async loads");
     // Create a nsIUnicharStreamLoader instance to which we will feed
     // the data from the sync load.  Do this before creating the
     // channel to make error recovery simpler.
     nsCOMPtr<nsIUnicharStreamLoader> streamLoader;
     rv = NS_NewUnicharStreamLoader(getter_AddRefs(streamLoader), aLoadData);
     if (NS_FAILED(rv)) {
       LOG_ERROR(("  Failed to create stream loader for sync load"));
       SheetComplete(aLoadData, rv);
       return rv;
     }
     if (mDocument) {
       mozilla::net::SeerLearn(aLoadData->mURI, mDocument->GetDocumentURI(),
                               nsINetworkSeer::LEARN_LOAD_SUBRESOURCE,
                               mDocument);
     }
     // Just load it
     nsCOMPtr<nsIInputStream> stream;
     nsCOMPtr<nsIChannel> channel;
     rv = NS_OpenURI(getter_AddRefs(stream), aLoadData->mURI, nullptr,
                     nullptr, nullptr, nsIRequest::LOAD_NORMAL,
                     getter_AddRefs(channel));
     if (NS_FAILED(rv)) {
       LOG_ERROR(("  Failed to open URI synchronously"));
       SheetComplete(aLoadData, rv);
       return rv;
     }
     NS_ASSERTION(channel, "NS_OpenURI lied?");
     // Force UA sheets to be UTF-8.
     // XXX this is only necessary because the default in
     // SheetLoadData::OnDetermineCharset is wrong (bug 521039).
     channel->SetContentCharset(NS_LITERAL_CSTRING("UTF-8"));
     // Manually feed the streamloader the contents of the stream we
     // got from NS_OpenURI.  This will call back into OnStreamComplete
     // and thence to ParseSheet.  Regardless of whether this fails,
     // SheetComplete has been called.
     return nsSyncLoadService::PushSyncStreamToListener(stream,
                                                        streamLoader,
                                                        channel);
   }
   SheetLoadData* existingData = nullptr;
   URIPrincipalAndCORSModeHashKey key(aLoadData->mURI,
                                      aLoadData->mLoaderPrincipal,
                                      aLoadData->mSheet->GetCORSMode());
   if (aSheetState == eSheetLoading) {
     mSheets->mLoadingDatas.Get(&key, &existingData);
     NS_ASSERTION(existingData, "CreateSheet lied about the state");
   }
   else if (aSheetState == eSheetPending){
     mSheets->mPendingDatas.Get(&key, &existingData);
     NS_ASSERTION(existingData, "CreateSheet lied about the state");
   }
   if (existingData) {
     LOG(("  Glomming on to existing load"));
     SheetLoadData* data = existingData;
     while (data->mNext) {
       data = data->mNext;
     }
     data->mNext = aLoadData; // transfer ownership
     if (aSheetState == eSheetPending && !aLoadData->mWasAlternate) {
       // Kick the load off; someone cares about it right away
 #ifdef DEBUG
       SheetLoadData* removedData;
       NS_ASSERTION(mSheets->mPendingDatas.Get(&key, &removedData) &&
                    removedData == existingData,
                    "Bad pending table.");
 #endif
       mSheets->mPendingDatas.Remove(&key);
       LOG(("  Forcing load of pending data"));
       return LoadSheet(existingData, eSheetNeedsParser);
     }
     // All done here; once the load completes we'll be marked complete
     // automatically
     return NS_OK;
   }
 #ifdef DEBUG
   mSyncCallback = true;
 #endif
   nsCOMPtr<nsILoadGroup> loadGroup;
   // Content Security Policy information to pass into channel
   nsCOMPtr<nsIChannelPolicy> channelPolicy;
   if (mDocument) {
     loadGroup = mDocument->GetDocumentLoadGroup();
     NS_ASSERTION(loadGroup,
                  "No loadgroup for stylesheet; onload will fire early");
     nsCOMPtr<nsIContentSecurityPolicy> csp;
     rv = mDocument->NodePrincipal()->GetCsp(getter_AddRefs(csp));
     NS_ENSURE_SUCCESS(rv, rv);
     if (csp) {
       channelPolicy = do_CreateInstance("@mozilla.org/nschannelpolicy;1");
       channelPolicy->SetContentSecurityPolicy(csp);
       channelPolicy->SetLoadType(nsIContentPolicy::TYPE_STYLESHEET);
     }
   }
   nsCOMPtr<nsIChannel> channel;
   rv = NS_NewChannel(getter_AddRefs(channel),
                      aLoadData->mURI, nullptr, loadGroup, nullptr,
                      nsIChannel::LOAD_NORMAL | nsIChannel::LOAD_CLASSIFY_URI,
                      channelPolicy);
   if (NS_FAILED(rv)) {
 #ifdef DEBUG
     mSyncCallback = false;
 #endif
     LOG_ERROR(("  Failed to create channel"));
     SheetComplete(aLoadData, rv);
     return rv;
   }
   nsCOMPtr<nsIHttpChannelInternal>
     internalHttpChannel(do_QueryInterface(channel));
   if (internalHttpChannel)
       internalHttpChannel->SetLoadAsBlocking(!aLoadData->mWasAlternate);
   nsCOMPtr<nsIHttpChannel> httpChannel(do_QueryInterface(channel));
   if (httpChannel) {
     // send a minimal Accept header for text/css
     httpChannel->SetRequestHeader(NS_LITERAL_CSTRING("Accept"),
                                   NS_LITERAL_CSTRING("text/css,*/*;q=0.1"),
                                   false);
     nsCOMPtr<nsIURI> referrerURI = aLoadData->GetReferrerURI();
     if (referrerURI)
       httpChannel->SetReferrer(referrerURI);
     // Set the initiator type
     nsCOMPtr<nsITimedChannel> timedChannel(do_QueryInterface(httpChannel));
     if (timedChannel) {
       if (aLoadData->mParentData) {
         timedChannel->SetInitiatorType(NS_LITERAL_STRING("css"));
       } else {
         timedChannel->SetInitiatorType(NS_LITERAL_STRING("link"));
       }
     }
   }
   // Now tell the channel we expect text/css data back....  We do
   // this before opening it, so it's only treated as a hint.
   channel->SetContentType(NS_LITERAL_CSTRING("text/css"));
   if (aLoadData->mLoaderPrincipal) {
     bool inherit;
     rv = NS_URIChainHasFlags(aLoadData->mURI,
                              nsIProtocolHandler::URI_INHERITS_SECURITY_CONTEXT,
                              &inherit);
     if ((NS_SUCCEEDED(rv) && inherit) ||
         (nsContentUtils::URIIsLocalFile(aLoadData->mURI) &&
          NS_SUCCEEDED(aLoadData->mLoaderPrincipal->
                       CheckMayLoad(aLoadData->mURI, false, false)))) {
       channel->SetOwner(aLoadData->mLoaderPrincipal);
     }
   }
   // We don't have to hold on to the stream loader.  The ownership
   // model is: Necko owns the stream loader, which owns the load data,
   // which owns us
   nsCOMPtr<nsIUnicharStreamLoader> streamLoader;
   rv = NS_NewUnicharStreamLoader(getter_AddRefs(streamLoader), aLoadData);
   if (NS_FAILED(rv)) {
 #ifdef DEBUG
     mSyncCallback = false;
 #endif
     LOG_ERROR(("  Failed to create stream loader"));
     SheetComplete(aLoadData, rv);
     return rv;
   }
   nsCOMPtr<nsIStreamListener> channelListener;
   CORSMode ourCORSMode = aLoadData->mSheet->GetCORSMode();
   if (ourCORSMode != CORS_NONE) {
     bool withCredentials = (ourCORSMode == CORS_USE_CREDENTIALS);
     LOG(("  Doing CORS-enabled load; credentials %d", withCredentials));
     nsRefPtr<nsCORSListenerProxy> corsListener =
       new nsCORSListenerProxy(streamLoader, aLoadData->mLoaderPrincipal,
 			      withCredentials);
     rv = corsListener->Init(channel);
     if (NS_FAILED(rv)) {
 #ifdef DEBUG
       mSyncCallback = false;
 #endif
       LOG_ERROR(("  Initial CORS check failed"));
       SheetComplete(aLoadData, rv);
       return rv;
     }
     channelListener = corsListener;
   } else {
     channelListener = streamLoader;
   }
   if (mDocument) {
     mozilla::net::SeerLearn(aLoadData->mURI, mDocument->GetDocumentURI(),
                             nsINetworkSeer::LEARN_LOAD_SUBRESOURCE, mDocument);
   }
   rv = channel->AsyncOpen(channelListener, nullptr);
 #ifdef DEBUG
   mSyncCallback = false;
 #endif
   if (NS_FAILED(rv)) {
     LOG_ERROR(("  Failed to create stream loader"));
     SheetComplete(aLoadData, rv);
     return rv;
   }
   mSheets->mLoadingDatas.Put(&key, aLoadData);
   aLoadData->mIsLoading = true;
   return NS_OK;
 }
 /**
  * ParseSheet handles parsing the data stream.  The main idea here is
  * to push the current load data onto the parse stack before letting
  * the CSS parser at the data stream.  That lets us handle @import
  * correctly.
  */
 nsresult
 Loader::ParseSheet(const nsAString& aInput,
                    SheetLoadData* aLoadData,
                    bool& aCompleted)
 {
   LOG(("css::Loader::ParseSheet"));
   NS_PRECONDITION(aLoadData, "Must have load data");
   NS_PRECONDITION(aLoadData->mSheet, "Must have sheet to parse into");
   aCompleted = false;
   nsCSSParser parser(this, aLoadData->mSheet);
   // Push our load data on the stack so any kids can pick it up
   mParsingDatas.AppendElement(aLoadData);
   nsIURI* sheetURI = aLoadData->mSheet->GetSheetURI();
   nsIURI* baseURI = aLoadData->mSheet->GetBaseURI();
   nsresult rv = parser.ParseSheet(aInput, sheetURI, baseURI,
                                   aLoadData->mSheet->Principal(),
                                   aLoadData->mLineNumber,
                                   aLoadData->mAllowUnsafeRules);
   mParsingDatas.RemoveElementAt(mParsingDatas.Length() - 1);
   if (NS_FAILED(rv)) {
     LOG_ERROR(("  Low-level error in parser!"));
     SheetComplete(aLoadData, rv);
     return rv;
   }
   NS_ASSERTION(aLoadData->mPendingChildren == 0 || !aLoadData->mSyncLoad,
                "Sync load has leftover pending children!");
   if (aLoadData->mPendingChildren == 0) {
     LOG(("  No pending kids from parse"));
     aCompleted = true;
     SheetComplete(aLoadData, NS_OK);
   }
   // Otherwise, the children are holding strong refs to the data and
   // will call SheetComplete() on it when they complete.
   return NS_OK;
 }
 /**
  * SheetComplete is the do-it-all cleanup function.  It removes the
  * load data from the "loading" hashtable, adds the sheet to the
  * "completed" hashtable, massages the XUL cache, handles siblings of
  * the load data (other loads for the same URI), handles unblocking
  * blocked parent loads as needed, and most importantly calls
  * NS_RELEASE on the load data to destroy the whole mess.
  */
 void
 Loader::SheetComplete(SheetLoadData* aLoadData, nsresult aStatus)
 {
   LOG(("css::Loader::SheetComplete"));
   // 8 is probably big enough for all our common cases.  It's not likely that
   // imports will nest more than 8 deep, and multiple sheets with the same URI
   // are rare.
   nsAutoTArray<nsRefPtr<SheetLoadData>, 8> datasToNotify;
   DoSheetComplete(aLoadData, aStatus, datasToNotify);
   // Now it's safe to go ahead and notify observers
   uint32_t count = datasToNotify.Length();
   mDatasToNotifyOn += count;
   for (uint32_t i = 0; i < count; ++i) {
     --mDatasToNotifyOn;
     SheetLoadData* data = datasToNotify[i];
     NS_ASSERTION(data && data->mMustNotify, "How did this data get here?");
     if (data->mObserver) {
       LOG(("  Notifying observer 0x%x for data 0x%x.  wasAlternate: %d",
            data->mObserver.get(), data, data->mWasAlternate));
       data->mObserver->StyleSheetLoaded(data->mSheet, data->mWasAlternate,
                                         aStatus);
     }
     nsTObserverArray<nsCOMPtr<nsICSSLoaderObserver> >::ForwardIterator iter(mObservers);
     nsCOMPtr<nsICSSLoaderObserver> obs;
     while (iter.HasMore()) {
       obs = iter.GetNext();
       LOG(("  Notifying global observer 0x%x for data 0x%s.  wasAlternate: %d",
            obs.get(), data, data->mWasAlternate));
       obs->StyleSheetLoaded(data->mSheet, data->mWasAlternate, aStatus);
     }
   }
   if (mSheets->mLoadingDatas.Count() == 0 && mSheets->mPendingDatas.Count() > 0) {
     LOG(("  No more loading sheets; starting alternates"));
     StartAlternateLoads();
   }
 }
 void
 Loader::DoSheetComplete(SheetLoadData* aLoadData, nsresult aStatus,
                         LoadDataArray& aDatasToNotify)
 {
   LOG(("css::Loader::DoSheetComplete"));
   NS_PRECONDITION(aLoadData, "Must have a load data!");
   NS_PRECONDITION(aLoadData->mSheet, "Must have a sheet");
   NS_ASSERTION(mSheets, "mLoadingDatas should be initialized by now.");
   LOG(("Load completed, status: 0x%x", aStatus));
   // Twiddle the hashtables
   if (aLoadData->mURI) {
     LOG_URI("  Finished loading: '%s'", aLoadData->mURI);
     // Remove the data from the list of loading datas
     if (aLoadData->mIsLoading) {
       URIPrincipalAndCORSModeHashKey key(aLoadData->mURI,
                                          aLoadData->mLoaderPrincipal,
                                          aLoadData->mSheet->GetCORSMode());
 #ifdef DEBUG
       SheetLoadData *loadingData;
       NS_ASSERTION(mSheets->mLoadingDatas.Get(&key, &loadingData) &&
                    loadingData == aLoadData,
                    "Bad loading table");
 #endif
       mSheets->mLoadingDatas.Remove(&key);
       aLoadData->mIsLoading = false;
     }
   }
   // Go through and deal with the whole linked list.
   SheetLoadData* data = aLoadData;
   while (data) {
     if (!data->mSheetAlreadyComplete) {
       // If mSheetAlreadyComplete, then the sheet could well be modified between
       // when we posted the async call to SheetComplete and now, since the sheet
       // was page-accessible during that whole time.
       NS_ABORT_IF_FALSE(!data->mSheet->IsModified(),
                         "should not get marked modified during parsing");
       data->mSheet->SetComplete();
       data->ScheduleLoadEventIfNeeded(aStatus);
     }
     if (data->mMustNotify && (data->mObserver || !mObservers.IsEmpty())) {
       // Don't notify here so we don't trigger script.  Remember the
       // info we need to notify, then do it later when it's safe.
       aDatasToNotify.AppendElement(data);
       // On append failure, just press on.  We'll fail to notify the observer,
       // but not much we can do about that....
     }
     NS_ASSERTION(!data->mParentData ||
                  data->mParentData->mPendingChildren != 0,
                  "Broken pending child count on our parent");
     // If we have a parent, our parent is no longer being parsed, and
     // we are the last pending child, then our load completion
     // completes the parent too.  Note that the parent _can_ still be
     // being parsed (eg if the child (us) failed to open the channel
     // or some such).
     if (data->mParentData &&
         --(data->mParentData->mPendingChildren) == 0 &&
         !mParsingDatas.Contains(data->mParentData)) {
       DoSheetComplete(data->mParentData, aStatus, aDatasToNotify);
     }
     data = data->mNext;
   }
   // Now that it's marked complete, put the sheet in our cache.
   // If we ever start doing this for failure aStatus, we'll need to
   // adjust the PostLoadEvent code that thinks anything already
   // complete must have loaded succesfully.
   if (NS_SUCCEEDED(aStatus) && aLoadData->mURI) {
     // Pick our sheet to cache carefully.  Ideally, we want to cache
     // one of the sheets that will be kept alive by a document or
     // parent sheet anyway, so that if someone then accesses it via
     // CSSOM we won't have extra clones of the inner lying around.
     data = aLoadData;
     nsCSSStyleSheet* sheet = aLoadData->mSheet;
     while (data) {
       if (data->mSheet->GetParentSheet() || data->mSheet->GetOwnerNode()) {
         sheet = data->mSheet;
         break;
       }
       data = data->mNext;
     }
 #ifdef MOZ_XUL
     if (IsChromeURI(aLoadData->mURI)) {
       nsXULPrototypeCache* cache = nsXULPrototypeCache::GetInstance();
       if (cache && cache->IsEnabled()) {
         if (!cache->GetStyleSheet(aLoadData->mURI)) {
           LOG(("  Putting sheet in XUL prototype cache"));
           NS_ASSERTION(sheet->IsComplete(),
                        "Should only be caching complete sheets");
           cache->PutStyleSheet(sheet);
         }
       }
     }
     else {
 #endif
       URIPrincipalAndCORSModeHashKey key(aLoadData->mURI,
                                          aLoadData->mLoaderPrincipal,
                                          aLoadData->mSheet->GetCORSMode());
       NS_ASSERTION(sheet->IsComplete(),
                    "Should only be caching complete sheets");
       mSheets->mCompleteSheets.Put(&key, sheet);
 #ifdef MOZ_XUL
     }
 #endif
   }
   NS_RELEASE(aLoadData);  // this will release parents and siblings and all that
 }
 nsresult
 Loader::LoadInlineStyle(nsIContent* aElement,
                         const nsAString& aBuffer,
                         uint32_t aLineNumber,
                         const nsAString& aTitle,
                         const nsAString& aMedia,
                         Element* aScopeElement,
                         nsICSSLoaderObserver* aObserver,
                         bool* aCompleted,
                         bool* aIsAlternate)
 {
   LOG(("css::Loader::LoadInlineStyle"));
   NS_ASSERTION(mParsingDatas.Length() == 0, "We're in the middle of a parse?");
   *aCompleted = true;
   if (!mEnabled) {
     LOG_WARN(("  Not enabled"));
     return NS_ERROR_NOT_AVAILABLE;
   }
   NS_ENSURE_TRUE(mDocument, NS_ERROR_NOT_INITIALIZED);
   nsCOMPtr<nsIStyleSheetLinkingElement> owningElement(do_QueryInterface(aElement));
   NS_ASSERTION(owningElement, "Element is not a style linking element!");
   // Since we're not planning to load a URI, no need to hand a principal to the
   // load data or to CreateSheet().  Also, OK to use CORS_NONE for the CORS
   // mode.
   StyleSheetState state;
   nsRefPtr<nsCSSStyleSheet> sheet;
   nsresult rv = CreateSheet(nullptr, aElement, nullptr, CORS_NONE, false, false,
                             aTitle, state, aIsAlternate, getter_AddRefs(sheet));
   NS_ENSURE_SUCCESS(rv, rv);
   NS_ASSERTION(state == eSheetNeedsParser,
                "Inline sheets should not be cached");
   LOG(("  Sheet is alternate: %d", *aIsAlternate));
   PrepareSheet(sheet, aTitle, aMedia, nullptr, aScopeElement, *aIsAlternate);
   if (aElement->HasFlag(NODE_IS_IN_SHADOW_TREE)) {
     ShadowRoot* containingShadow = aElement->GetContainingShadow();
     MOZ_ASSERT(containingShadow);
     containingShadow->InsertSheet(sheet, aElement);
   } else {
     rv = InsertSheetInDoc(sheet, aElement, mDocument);
     NS_ENSURE_SUCCESS(rv, rv);
   }
   SheetLoadData* data = new SheetLoadData(this, aTitle, nullptr, sheet,
                                           owningElement, *aIsAlternate,
                                           aObserver, nullptr);
   // We never actually load this, so just set its principal directly
   sheet->SetPrincipal(aElement->NodePrincipal());
   NS_ADDREF(data);
   data->mLineNumber = aLineNumber;
   // Parse completion releases the load data
   rv = ParseSheet(aBuffer, data, *aCompleted);
   NS_ENSURE_SUCCESS(rv, rv);
   // If aCompleted is true, |data| may well be deleted by now.
   if (!*aCompleted) {
     data->mMustNotify = true;
   }
   return rv;
 }
 nsresult
 Loader::LoadStyleLink(nsIContent* aElement,
                       nsIURI* aURL,
                       const nsAString& aTitle,
                       const nsAString& aMedia,
                       bool aHasAlternateRel,
                       CORSMode aCORSMode,
                       nsICSSLoaderObserver* aObserver,
                       bool* aIsAlternate)
 {
   LOG(("css::Loader::LoadStyleLink"));
   NS_PRECONDITION(aURL, "Must have URL to load");
   NS_ASSERTION(mParsingDatas.Length() == 0, "We're in the middle of a parse?");
   LOG_URI("  Link uri: '%s'", aURL);
   LOG(("  Link title: '%s'", NS_ConvertUTF16toUTF8(aTitle).get()));
   LOG(("  Link media: '%s'", NS_ConvertUTF16toUTF8(aMedia).get()));
   LOG(("  Link alternate rel: %d", aHasAlternateRel));
   if (!mEnabled) {
     LOG_WARN(("  Not enabled"));
     return NS_ERROR_NOT_AVAILABLE;
   }
   NS_ENSURE_TRUE(mDocument, NS_ERROR_NOT_INITIALIZED);
   nsIPrincipal* principal =
     aElement ? aElement->NodePrincipal() : mDocument->NodePrincipal();
   nsISupports* context = aElement;
   if (!context) {
     context = mDocument;
   }
   nsresult rv = CheckLoadAllowed(principal, aURL, context);
   if (NS_FAILED(rv)) return rv;
   LOG(("  Passed load check"));
   StyleSheetState state;
   nsRefPtr<nsCSSStyleSheet> sheet;
   rv = CreateSheet(aURL, aElement, principal, aCORSMode, false,
                    aHasAlternateRel, aTitle, state, aIsAlternate,
                    getter_AddRefs(sheet));
   NS_ENSURE_SUCCESS(rv, rv);
   LOG(("  Sheet is alternate: %d", *aIsAlternate));
   PrepareSheet(sheet, aTitle, aMedia, nullptr, nullptr, *aIsAlternate);
   rv = InsertSheetInDoc(sheet, aElement, mDocument);
   NS_ENSURE_SUCCESS(rv, rv);
   nsCOMPtr<nsIStyleSheetLinkingElement> owningElement(do_QueryInterface(aElement));
   if (state == eSheetComplete) {
     LOG(("  Sheet already complete: 0x%p",
          static_cast<void*>(sheet.get())));
     if (aObserver || !mObservers.IsEmpty() || owningElement) {
       rv = PostLoadEvent(aURL, sheet, aObserver, *aIsAlternate,
                          owningElement);
       return rv;
     }
     return NS_OK;
   }
   // Now we need to actually load it
   SheetLoadData* data = new SheetLoadData(this, aTitle, aURL, sheet,
                                           owningElement, *aIsAlternate,
                                           aObserver, principal);
   NS_ADDREF(data);
   // If we have to parse and it's an alternate non-inline, defer it
   if (aURL && state == eSheetNeedsParser && mSheets->mLoadingDatas.Count() != 0 &&
       *aIsAlternate) {
     LOG(("  Deferring alternate sheet load"));
     URIPrincipalAndCORSModeHashKey key(data->mURI, data->mLoaderPrincipal,
                                        data->mSheet->GetCORSMode());
     mSheets->mPendingDatas.Put(&key, data);
     data->mMustNotify = true;
     return NS_OK;
   }
   // Load completion will free the data
   rv = LoadSheet(data, state);
   NS_ENSURE_SUCCESS(rv, rv);
   data->mMustNotify = true;
   return rv;
 }
 static bool
 HaveAncestorDataWithURI(SheetLoadData *aData, nsIURI *aURI)
 {
   if (!aData->mURI) {
     // Inline style; this won't have any ancestors
     NS_ABORT_IF_FALSE(!aData->mParentData,
                       "How does inline style have a parent?");
     return false;
   }
   bool equal;
   if (NS_FAILED(aData->mURI->Equals(aURI, &equal)) || equal) {
     return true;
   }
   // Datas down the mNext chain have the same URI as aData, so we
   // don't have to compare to them.  But they might have different
   // parents, and we have to check all of those.
   while (aData) {
     if (aData->mParentData &&
         HaveAncestorDataWithURI(aData->mParentData, aURI)) {
       return true;
     }
     aData = aData->mNext;
   }
   return false;
 }
 nsresult
 Loader::LoadChildSheet(nsCSSStyleSheet* aParentSheet,
                        nsIURI* aURL,
                        nsMediaList* aMedia,
                        ImportRule* aParentRule)
 {
   LOG(("css::Loader::LoadChildSheet"));
   NS_PRECONDITION(aURL, "Must have a URI to load");
   NS_PRECONDITION(aParentSheet, "Must have a parent sheet");
   if (!mEnabled) {
     LOG_WARN(("  Not enabled"));
     return NS_ERROR_NOT_AVAILABLE;
   }
   LOG_URI("  Child uri: '%s'", aURL);
   nsCOMPtr<nsIDOMNode> owningNode;
   // check for an owning document: if none, don't bother walking up the parent
   // sheets
   if (aParentSheet->GetOwningDocument()) {
     nsCOMPtr<nsIDOMStyleSheet> nextParentSheet(aParentSheet);
     NS_ENSURE_TRUE(nextParentSheet, NS_ERROR_FAILURE); //Not a stylesheet!?
     nsCOMPtr<nsIDOMStyleSheet> topSheet;
     //traverse our way to the top-most sheet
     do {
       topSheet.swap(nextParentSheet);
       topSheet->GetParentStyleSheet(getter_AddRefs(nextParentSheet));
     } while (nextParentSheet);
     topSheet->GetOwnerNode(getter_AddRefs(owningNode));
   }
   nsISupports* context = owningNode;
   if (!context) {
     context = mDocument;
   }
   nsIPrincipal* principal = aParentSheet->Principal();
   nsresult rv = CheckLoadAllowed(principal, aURL, context);
   if (NS_FAILED(rv)) return rv;
   LOG(("  Passed load check"));
   SheetLoadData* parentData = nullptr;
   nsCOMPtr<nsICSSLoaderObserver> observer;
   int32_t count = mParsingDatas.Length();
   if (count > 0) {
     LOG(("  Have a parent load"));
     parentData = mParsingDatas.ElementAt(count - 1);
     // Check for cycles
     if (HaveAncestorDataWithURI(parentData, aURL)) {
       // Houston, we have a loop, blow off this child and pretend this never
       // happened
       LOG_ERROR(("  @import cycle detected, dropping load"));
       return NS_OK;
     }
     NS_ASSERTION(parentData->mSheet == aParentSheet,
                  "Unexpected call to LoadChildSheet");
   } else {
     LOG(("  No parent load; must be CSSOM"));
     // No parent load data, so the sheet will need to be notified when
     // we finish, if it can be, if we do the load asynchronously.
     observer = aParentSheet;
   }
   // Now that we know it's safe to load this (passes security check and not a
   // loop) do so.
   nsRefPtr<nsCSSStyleSheet> sheet;
   bool isAlternate;
   StyleSheetState state;
   const nsSubstring& empty = EmptyString();
   // For now, use CORS_NONE for child sheets
   rv = CreateSheet(aURL, nullptr, principal, CORS_NONE,
                    parentData ? parentData->mSyncLoad : false,
                    false, empty, state, &isAlternate, getter_AddRefs(sheet));
   NS_ENSURE_SUCCESS(rv, rv);
   PrepareSheet(sheet, empty, empty, aMedia, nullptr, isAlternate);
   rv = InsertChildSheet(sheet, aParentSheet, aParentRule);
   NS_ENSURE_SUCCESS(rv, rv);
   if (state == eSheetComplete) {
     LOG(("  Sheet already complete"));
     // We're completely done.  No need to notify, even, since the
     // @import rule addition/modification will trigger the right style
     // changes automatically.
     return NS_OK;
   }
   SheetLoadData* data = new SheetLoadData(this, aURL, sheet, parentData,
                                           observer, principal);
   NS_ADDREF(data);
   bool syncLoad = data->mSyncLoad;
   // Load completion will release the data
   rv = LoadSheet(data, state);
   NS_ENSURE_SUCCESS(rv, rv);
   // If syncLoad is true, |data| will be deleted by now.
   if (!syncLoad) {
     data->mMustNotify = true;
   }
   return rv;
 }
 nsresult
 Loader::LoadSheetSync(nsIURI* aURL, bool aAllowUnsafeRules,
                       bool aUseSystemPrincipal,
                       nsCSSStyleSheet** aSheet)
 {
   LOG(("css::Loader::LoadSheetSync"));
   return InternalLoadNonDocumentSheet(aURL, aAllowUnsafeRules,
                                       aUseSystemPrincipal, nullptr,
                                       EmptyCString(), aSheet, nullptr);
 }
 nsresult
 Loader::LoadSheet(nsIURI* aURL,
                   nsIPrincipal* aOriginPrincipal,
                   const nsCString& aCharset,
                   nsICSSLoaderObserver* aObserver,
                   nsCSSStyleSheet** aSheet)
 {
   LOG(("css::Loader::LoadSheet(aURL, aObserver, aSheet) api call"));
   NS_PRECONDITION(aSheet, "aSheet is null");
   return InternalLoadNonDocumentSheet(aURL, false, false,
                                       aOriginPrincipal, aCharset,
                                       aSheet, aObserver);
 }
 nsresult
 Loader::LoadSheet(nsIURI* aURL,
                   nsIPrincipal* aOriginPrincipal,
                   const nsCString& aCharset,
                   nsICSSLoaderObserver* aObserver,
                   CORSMode aCORSMode)
 {
   LOG(("css::Loader::LoadSheet(aURL, aObserver) api call"));
   return InternalLoadNonDocumentSheet(aURL, false, false,
                                       aOriginPrincipal, aCharset,
                                       nullptr, aObserver, aCORSMode);
 }
 nsresult
 Loader::InternalLoadNonDocumentSheet(nsIURI* aURL,
                                      bool aAllowUnsafeRules,
                                      bool aUseSystemPrincipal,
                                      nsIPrincipal* aOriginPrincipal,
                                      const nsCString& aCharset,
                                      nsCSSStyleSheet** aSheet,
                                      nsICSSLoaderObserver* aObserver,
                                      CORSMode aCORSMode)
 {
   NS_PRECONDITION(aURL, "Must have a URI to load");
   NS_PRECONDITION(aSheet || aObserver, "Sheet and observer can't both be null");
   NS_PRECONDITION(!aUseSystemPrincipal || !aObserver,
                   "Shouldn't load system-principal sheets async");
   NS_ASSERTION(mParsingDatas.Length() == 0, "We're in the middle of a parse?");
   LOG_URI("  Non-document sheet uri: '%s'", aURL);
   if (aSheet) {
     *aSheet = nullptr;
   }
   if (!mEnabled) {
     LOG_WARN(("  Not enabled"));
     return NS_ERROR_NOT_AVAILABLE;
   }
   nsresult rv = CheckLoadAllowed(aOriginPrincipal, aURL, mDocument);
   if (NS_FAILED(rv)) {
     return rv;
   }
   StyleSheetState state;
   bool isAlternate;
   nsRefPtr<nsCSSStyleSheet> sheet;
   bool syncLoad = (aObserver == nullptr);
   const nsSubstring& empty = EmptyString();
   rv = CreateSheet(aURL, nullptr, aOriginPrincipal, aCORSMode, syncLoad, false,
                    empty, state, &isAlternate, getter_AddRefs(sheet));
   NS_ENSURE_SUCCESS(rv, rv);
   PrepareSheet(sheet, empty, empty, nullptr, nullptr, isAlternate);
   if (state == eSheetComplete) {
     LOG(("  Sheet already complete"));
     if (aObserver || !mObservers.IsEmpty()) {
       rv = PostLoadEvent(aURL, sheet, aObserver, false, nullptr);
     }
     if (aSheet) {
       sheet.swap(*aSheet);
     }
     return rv;
   }
   SheetLoadData* data =
     new SheetLoadData(this, aURL, sheet, syncLoad, aAllowUnsafeRules,
                       aUseSystemPrincipal, aCharset, aObserver,
                       aOriginPrincipal);
   NS_ADDREF(data);
   rv = LoadSheet(data, state);
   NS_ENSURE_SUCCESS(rv, rv);
   if (aSheet) {
     sheet.swap(*aSheet);
   }
   if (aObserver) {
     data->mMustNotify = true;
   }
   return rv;
 }
 nsresult
 Loader::PostLoadEvent(nsIURI* aURI,
                       nsCSSStyleSheet* aSheet,
                       nsICSSLoaderObserver* aObserver,
                       bool aWasAlternate,
                       nsIStyleSheetLinkingElement* aElement)
 {
   LOG(("css::Loader::PostLoadEvent"));
   NS_PRECONDITION(aSheet, "Must have sheet");
   NS_PRECONDITION(aObserver || !mObservers.IsEmpty() || aElement,
                   "Must have observer or element");
   nsRefPtr<SheetLoadData> evt =
     new SheetLoadData(this, EmptyString(), // title doesn't matter here
                       aURI,
                       aSheet,
                       aElement,
                       aWasAlternate,
                       aObserver,
                       nullptr);
   NS_ENSURE_TRUE(evt, NS_ERROR_OUT_OF_MEMORY);
   if (!mPostedEvents.AppendElement(evt)) {
     return NS_ERROR_OUT_OF_MEMORY;
   }
   nsresult rv = NS_DispatchToCurrentThread(evt);
   if (NS_FAILED(rv)) {
     NS_WARNING("failed to dispatch stylesheet load event");
     mPostedEvents.RemoveElement(evt);
   } else {
     // We'll unblock onload when we handle the event.
     if (mDocument) {
       mDocument->BlockOnload();
     }
     // We want to notify the observer for this data.
     evt->mMustNotify = true;
     evt->mSheetAlreadyComplete = true;
     // If we get to this code, aSheet loaded correctly at some point, so
     // we can just use NS_OK for the status.  Note that we do this here
     // and not from inside our SheetComplete so that we don't end up
     // running the load event async.
     evt->ScheduleLoadEventIfNeeded(NS_OK);
   }
   return rv;
 }
 void
 Loader::HandleLoadEvent(SheetLoadData* aEvent)
 {
   // XXXbz can't assert this yet.... May not have an observer because
   // we're unblocking the parser
   // NS_ASSERTION(aEvent->mObserver, "Must have observer");
   NS_ASSERTION(aEvent->mSheet, "Must have sheet");
   // Very important: this needs to come before the SheetComplete call
   // below, so that HasPendingLoads() will test true as needed under
   // notifications we send from that SheetComplete call.
   mPostedEvents.RemoveElement(aEvent);
   if (!aEvent->mIsCancelled) {
     // SheetComplete will call Release(), so give it a reference to do
     // that with.
     NS_ADDREF(aEvent);
     SheetComplete(aEvent, NS_OK);
   }
   if (mDocument) {
     mDocument->UnblockOnload(true);
   }
 }
 static PLDHashOperator
 StopLoadingSheetCallback(URIPrincipalAndCORSModeHashKey* aKey,
                          SheetLoadData*& aData,
                          void* aClosure)
 {
   NS_PRECONDITION(aData, "Must have a data!");
   NS_PRECONDITION(aClosure, "Must have a loader");
   aData->mIsLoading = false; // we will handle the removal right here
   aData->mIsCancelled = true;
   static_cast<Loader::LoadDataArray*>(aClosure)->AppendElement(aData);
   return PL_DHASH_REMOVE;
 }
 nsresult
 Loader::Stop()
 {
   uint32_t pendingCount =
     mSheets ? mSheets->mPendingDatas.Count() : 0;
   uint32_t loadingCount =
     mSheets ? mSheets->mLoadingDatas.Count() : 0;
   LoadDataArray arr(pendingCount + loadingCount + mPostedEvents.Length());
   if (pendingCount) {
     mSheets->mPendingDatas.Enumerate(StopLoadingSheetCallback, &arr);
   }
   if (loadingCount) {
     mSheets->mLoadingDatas.Enumerate(StopLoadingSheetCallback, &arr);
   }
   uint32_t i;
   for (i = 0; i < mPostedEvents.Length(); ++i) {
     SheetLoadData* data = mPostedEvents[i];
     data->mIsCancelled = true;
     if (arr.AppendElement(data)) {
       // SheetComplete() calls Release(), so give this an extra ref.
       NS_ADDREF(data);
     }
 #ifdef DEBUG
     else {
       NS_NOTREACHED("We preallocated this memory... shouldn't really fail, "
                     "except we never check that preallocation succeeds.");
     }
 #endif
   }
   mPostedEvents.Clear();
   mDatasToNotifyOn += arr.Length();
   for (i = 0; i < arr.Length(); ++i) {
     --mDatasToNotifyOn;
     SheetComplete(arr[i], NS_BINDING_ABORTED);
   }
   return NS_OK;
 }
 bool
 Loader::HasPendingLoads()
 {
   return
     (mSheets && mSheets->mLoadingDatas.Count() != 0) ||
     (mSheets && mSheets->mPendingDatas.Count() != 0) ||
     mPostedEvents.Length() != 0 ||
     mDatasToNotifyOn != 0;
 }
 nsresult
 Loader::AddObserver(nsICSSLoaderObserver* aObserver)
 {
   NS_PRECONDITION(aObserver, "Must have observer");
   if (mObservers.AppendElementUnlessExists(aObserver)) {
     return NS_OK;
   }
   return NS_ERROR_OUT_OF_MEMORY;
 }
 void
 Loader::RemoveObserver(nsICSSLoaderObserver* aObserver)
 {
   mObservers.RemoveElement(aObserver);
 }
 static PLDHashOperator
 CollectLoadDatas(URIPrincipalAndCORSModeHashKey *aKey,
                  SheetLoadData* &aData,
                  void* aClosure)
 {
   static_cast<Loader::LoadDataArray*>(aClosure)->AppendElement(aData);
   return PL_DHASH_REMOVE;
 }
 void
 Loader::StartAlternateLoads()
 {
   NS_PRECONDITION(mSheets, "Don't call me!");
   LoadDataArray arr(mSheets->mPendingDatas.Count());
   mSheets->mPendingDatas.Enumerate(CollectLoadDatas, &arr);
   mDatasToNotifyOn += arr.Length();
   for (uint32_t i = 0; i < arr.Length(); ++i) {
     --mDatasToNotifyOn;
     LoadSheet(arr[i], eSheetNeedsParser);
   }
 }
 static PLDHashOperator
 TraverseSheet(URIPrincipalAndCORSModeHashKey*,
               nsCSSStyleSheet* aSheet,
               void* aClosure)
 {
   nsCycleCollectionTraversalCallback* cb =
     static_cast<nsCycleCollectionTraversalCallback*>(aClosure);
   NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(*cb, "Sheet cache nsCSSLoader");
   cb->NoteXPCOMChild(NS_ISUPPORTS_CAST(nsIStyleSheet*, aSheet));
   return PL_DHASH_NEXT;
 }
 void
 Loader::TraverseCachedSheets(nsCycleCollectionTraversalCallback& cb)
 {
   if (mSheets) {
     mSheets->mCompleteSheets.EnumerateRead(TraverseSheet, &cb);
   }
 }
 void
 Loader::UnlinkCachedSheets()
 {
   if (mSheets) {
     mSheets->mCompleteSheets.Clear();
   }
 }
 struct SheetMemoryCounter {
   size_t size;
   mozilla::MallocSizeOf mallocSizeOf;
 };
 static size_t
 CountSheetMemory(URIPrincipalAndCORSModeHashKey* /* unused */,
                  const nsRefPtr<nsCSSStyleSheet>& aSheet,
                  mozilla::MallocSizeOf aMallocSizeOf,
                  void* /* unused */)
 {
   // If aSheet has a parent, then its parent will report it so we don't
   // have to worry about it here.
   // Likewise, if aSheet has an owning node, then the document that
   // node is in will report it.
   if (aSheet->GetOwnerNode() || aSheet->GetParentSheet()) {
     return 0;
   }
   return aSheet->SizeOfIncludingThis(aMallocSizeOf);
 }
 size_t
 Loader::SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const
 {
   size_t s = aMallocSizeOf(this);
   if (mSheets) {
     s += mSheets->mCompleteSheets.SizeOfExcludingThis(CountSheetMemory, aMallocSizeOf);
   }
   s += mObservers.SizeOfExcludingThis(aMallocSizeOf);
   // Measurement of the following members may be added later if DMD finds it is
   // worthwhile:
   // - mLoadingDatas: transient, and should be small
   // - mPendingDatas: transient, and should be small
   // - mParsingDatas: transient, and should be small
   // - mPostedEvents: transient, and should be small
   //
   // The following members aren't measured:
   // - mDocument, because it's a weak backpointer
   // - mPreferredSheet, because it can be a shared string
   return s;
 }
 } // namespace css
 } // namespace mozilla

The Tor Browser / annotate

layout/style/Loader.cpp@deefc01c0e14 (annotated)

layout/style/Loader.cpp