Bug 1415940 Part 1: Expand StyleSheet dirty flag into a bitfield, to allow more types of dirtiness. r=bz

MozReview-Commit-ID: 7IasNqj85il

--HG--
extra : rebase_source : 414548a7a0d413917bd72ee3fc384cf2280c334b

dom/base/nsTreeSanitizer.cpp

@@ -1112,8 +1112,8 @@ nsTreeSanitizer::SanitizeStyleSheet(const nsAString& aOriginal,
   }
   NS_ENSURE_SUCCESS(rv, true);
   // Mark the sheet as complete.
-  MOZ_ASSERT(!sheet->IsModified(),
-             "should not get marked modified during parsing");
+  MOZ_ASSERT(!sheet->HasForcedUniqueInner(),
+             "should not get a forced unique inner during parsing");
   sheet->SetComplete();
   // Loop through all the rules found in the CSS text
   ErrorResult err;

layout/style/CSSStyleSheet.cpp

@@ -353,7 +353,7 @@ CSSStyleSheet::CSSStyleSheet(const CSSStyleSheet& aCopy,
   , mScopeElement(nullptr)
   , mRuleProcessors(nullptr)
 {
-  if (mDirty) { // CSSOM's been there, force full copy now
+  if (HasForcedUniqueInner()) { // CSSOM's been there, force full copy now
     NS_ASSERTION(mInner->mComplete,
                  "Why have rules been accessed on an incomplete sheet?");
     // FIXME: handle failure?
@@ -610,7 +610,7 @@ CSSStyleSheet::ClearRuleCascades()
 void
 CSSStyleSheet::DidDirty()
 {
-  MOZ_ASSERT(!mInner->mComplete || mDirty,
+  MOZ_ASSERT(!mInner->mComplete || HasForcedUniqueInner(),
              "caller must have called WillDirty()");
   ClearRuleCascades();
 }

layout/style/Loader.cpp

@@ -1003,9 +1003,12 @@ Loader::CreateSheet(nsIURI* aURI,
       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",
+      // Make sure it hasn't been forced to have a unique inner;
+      // that is an indication that its rules have been exposed to
+      // CSSOM and so we can't use it.
+      if (sheet->HasForcedUniqueInner()) {
+        LOG(("  Not cloning completed sheet %p because it has a "
+             "forced unique inner",
              sheet.get()));
         sheet = nullptr;
         fromCompleteSheets = false;
@@ -1056,10 +1059,11 @@ Loader::CreateSheet(nsIURI* aURI,
     }
 
     if (sheet) {
-      // The sheet we have now should be either incomplete or unmodified
-      NS_ASSERTION(!sheet->IsModified() ||
+      // The sheet we have now should be either incomplete or without
+      // a forced unique inner.
+      NS_ASSERTION(!sheet->HasForcedUniqueInner() ||
                    !sheet->IsComplete(),
-                   "Unexpected modified complete sheet");
+                   "Unexpected complete sheet with forced unique inner");
       NS_ASSERTION(sheet->IsComplete() ||
                    aSheetState != eSheetComplete,
                    "Sheet thinks it's not complete while we think it is");
@@ -1812,8 +1816,8 @@ Loader::DoSheetComplete(SheetLoadData* aLoadData, nsresult aStatus,
       // 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.
-      MOZ_ASSERT(!data->mSheet->IsModified(),
-                 "should not get marked modified during parsing");
+      MOZ_ASSERT(!data->mSheet->HasForcedUniqueInner(),
+                 "should not get a forced unique inner during parsing");
       data->mSheet->SetComplete();
       data->ScheduleLoadEventIfNeeded(aStatus);
     }

layout/style/ServoStyleSheet.cpp

@@ -149,7 +149,7 @@ ServoStyleSheet::ServoStyleSheet(const ServoStyleSheet& aCopy,
                aDocumentToUse,
                aOwningNodeToUse)
 {
-  if (mDirty) { // CSSOM's been there, force full copy now
+  if (HasForcedUniqueInner()) { // CSSOM's been there, force full copy now
     NS_ASSERTION(mInner->mComplete,
                  "Why have rules been accessed on an incomplete sheet?");
     // FIXME: handle failure?

layout/style/StyleSheet.cpp

@@ -28,7 +28,7 @@ StyleSheet::StyleSheet(StyleBackendType aType, css::SheetParsingMode aParsingMod
   , mParsingMode(aParsingMode)
   , mType(aType)
   , mDisabled(false)
-  , mDirty(false)
+  , mDirtyFlags(0)
   , mDocumentAssociationMode(NotOwnedByDocument)
   , mInner(nullptr)
 {
@@ -47,7 +47,7 @@ StyleSheet::StyleSheet(const StyleSheet& aCopy,
   , mParsingMode(aCopy.mParsingMode)
   , mType(aCopy.mType)
   , mDisabled(aCopy.mDisabled)
-  , mDirty(aCopy.mDirty)
+  , mDirtyFlags(aCopy.mDirtyFlags)
   // We only use this constructor during cloning.  It's the cloner's
   // responsibility to notify us if we end up being owned by a document.
   , mDocumentAssociationMode(NotOwnedByDocument)
@@ -196,7 +196,9 @@ StyleSheet::IsComplete() const
 void
 StyleSheet::SetComplete()
 {
-  NS_ASSERTION(!mDirty, "Can't set a dirty sheet complete!");
+  NS_ASSERTION(!HasForcedUniqueInner(),
+               "Can't complete a sheet that's already been forced "
+               "unique.");
   SheetInfo().mComplete = true;
   if (mDocument && !mDisabled) {
     // Let the document know
@@ -377,7 +379,7 @@ StyleSheet::EnsureUniqueInner()
 {
   MOZ_ASSERT(mInner->mSheets.Length() != 0,
              "unexpected number of outers");
-  mDirty = true;
+  mDirtyFlags |= FORCED_UNIQUE_INNER;
 
   if (HasUniqueInner()) {
     // already unique

layout/style/StyleSheet.h

@@ -132,7 +132,8 @@ public:
                                              nsIDocument* aCloneDocument,
                                              nsINode* aCloneOwningNode) const = 0;
 
-  bool IsModified() const { return mDirty; }
+  bool HasForcedUniqueInner() const { return mDirtyFlags &
+                                             FORCED_UNIQUE_INNER; }
 
   inline bool HasUniqueInner() const;
   void EnsureUniqueInner();
@@ -338,7 +339,10 @@ protected:
   const StyleBackendType mType;
   bool                  mDisabled;
 
-  bool mDirty; // has been modified
+  enum dirtyFlagAttributes {
+    FORCED_UNIQUE_INNER = 0x1,
+  };
+  uint8_t mDirtyFlags; // has been modified
 
   // mDocumentAssociationMode determines whether mDocument directly owns us (in
   // the sense that if it's known-live then we're known-live).  Always