Bug 1286445: stylo: Support restyles of non-pseudo content on state change. r=heycam

This includes, for example :hover.

Also removes the call to IsStyledByServo() in the document constructor, it's not
only unnecessary, but also we call UpdateStyleBackendType() too early.

MozReview-Commit-ID: 4YfCdmLoSxu

dom/base/nsDocument.cpp

@@ -1459,9 +1459,6 @@ nsIDocument::nsIDocument()
     mUserHasInteracted(false)
 {
   SetIsDocument();
-  if (IsStyledByServo()) {
-    SetFlags(NODE_IS_DIRTY_FOR_SERVO | NODE_HAS_DIRTY_DESCENDANTS_FOR_SERVO);
-  }
 
   PR_INIT_CLIST(&mDOMMediaQueryLists);
 }

dom/xbl/nsXBLBinding.cpp

@@ -240,7 +240,7 @@ nsXBLBinding::InstallAnonymousContent(nsIContent* aAnonParent, nsIContent* aElem
 #endif
 
     if (servoStyleSet) {
-      servoStyleSet->RestyleSubtree(child);
+      servoStyleSet->RestyleSubtree(child, /* aForce = */ true);
     }
   }
 }

layout/base/ServoRestyleManager.cpp

@@ -16,10 +16,26 @@ ServoRestyleManager::ServoRestyleManager(nsPresContext* aPresContext)
 {
 }
 
-void
-ServoRestyleManager::Disconnect()
+/* static */ void
+ServoRestyleManager::DirtyTree(nsIContent* aContent)
 {
-  NS_ERROR("stylo: ServoRestyleManager::Disconnect not implemented");
+  if (aContent->IsDirtyForServo()) {
+    return;
+  }
+
+  aContent->SetIsDirtyForServo();
+
+  FlattenedChildIterator it(aContent);
+
+  nsIContent* n = it.GetNextChild();
+  bool hadChildren = bool(n);
+  for ( ; n; n = it.GetNextChild()) {
+    DirtyTree(n);
+  }
+
+  if (hadChildren) {
+    aContent->SetHasDirtyDescendantsForServo();
+  }
 }
 
 void
@@ -32,13 +48,21 @@ ServoRestyleManager::PostRestyleEvent(Element* aElement,
     return;
   }
 
+  if (aRestyleHint == 0 && !aMinChangeHint) {
+    // Nothing to do here
+    return;
+  }
+
   nsIPresShell* presShell = PresContext()->PresShell();
   if (!ObservingRefreshDriver()) {
     SetObservingRefreshDriver(PresContext()->RefreshDriver()->
         AddStyleFlushObserver(presShell));
   }
 
-  aElement->SetIsDirtyForServo();
+  // Propagate the IS_DIRTY flag down the tree.
+  DirtyTree(aElement);
+
+  // Propagate the HAS_DIRTY_DESCENDANTS flag to the root.
   nsINode* cur = aElement;
   while ((cur = cur->GetParentNode())) {
     if (cur->HasDirtyDescendantsForServo())
@@ -69,10 +93,59 @@ ServoRestyleManager::PostRebuildAllStyleDataEvent(nsChangeHint aExtraHint,
   MOZ_CRASH("stylo: ServoRestyleManager::PostRebuildAllStyleDataEvent not implemented");
 }
 
+/* static */ void
+ServoRestyleManager::RecreateStyleContexts(nsIContent* aContent,
+                                           nsStyleContext* aParentContext,
+                                           ServoStyleSet* aStyleSet)
+{
+  if (!(aContent->IsDirtyForServo() || aContent->HasDirtyDescendantsForServo())) {
+    return;
+  }
+
+  nsIFrame* primaryFrame = aContent->GetPrimaryFrame();
+
+  // TODO: AFAIK this can happen when we have, let's say, display: none. Here we
+  // should trigger frame construction if the element is actually dirty (I
+  // guess), but we'd better do that once we have all the restyle hints thing
+  // figured out.
+  if (!primaryFrame) {
+    return;
+  }
+
+  RefPtr<ServoComputedValues> computedValues =
+    dont_AddRef(Servo_GetComputedValues(aContent));
+
+  // TODO: Figure out what pseudos does this content have, and do the proper
+  // thing with them.
+  RefPtr<nsStyleContext> context =
+    aStyleSet->GetContext(computedValues.forget(),
+                          aParentContext,
+                          nullptr,
+                          CSSPseudoElementType::NotPseudo);
+
+  // TODO: Compare old and new styles to generate restyle change hints, and
+  // process them.
+  primaryFrame->SetStyleContext(context.get());
+
+  FlattenedChildIterator it(aContent);
+  for (nsIContent* n = it.GetNextChild(); n; n = it.GetNextChild()) {
+    RecreateStyleContexts(n, context.get(), aStyleSet);
+  }
+}
+
 void
 ServoRestyleManager::ProcessPendingRestyles()
 {
-  // XXXheycam Do nothing for now.
+  ServoStyleSet* styleSet = StyleSet();
+
+  nsIDocument* doc = PresContext()->Document();
+  Element* root = doc->GetRootElement();
+
+  if (root) {
+    styleSet->RestyleSubtree(root, /* aForce = */ false);
+    RecreateStyleContexts(root, nullptr, styleSet);
+  }
+
   IncrementRestyleGeneration();
 }
 

layout/base/ServoRestyleManager.h

@@ -31,12 +31,12 @@ namespace mozilla {
  */
 class ServoRestyleManager : public RestyleManagerBase
 {
+  friend class ServoStyleSet;
 public:
   NS_INLINE_DECL_REFCOUNTING(ServoRestyleManager)
 
   explicit ServoRestyleManager(nsPresContext* aPresContext);
 
-  void Disconnect();
   void PostRestyleEvent(dom::Element* aElement,
                         nsRestyleHint aRestyleHint,
                         nsChangeHint aMinChangeHint);
@@ -72,6 +72,24 @@ protected:
   ~ServoRestyleManager() {}
 
 private:
+  /**
+   * Traverses a tree of content that Servo has just restyled, recreating style
+   * contexts for their frames with the new style data.
+   *
+   * This is just static so ServoStyleSet can mark this class as friend, so we
+   * can access to the GetContext method without making it available to everyone
+   * else.
+   */
+  static void RecreateStyleContexts(nsIContent* aContent,
+                                    nsStyleContext* aParentContext,
+                                    ServoStyleSet* aStyleSet);
+
+  /**
+   * Propagates the IS_DIRTY flag down to the tree, setting
+   * HAS_DIRTY_DESCENDANTS appropriately.
+   */
+  static void DirtyTree(nsIContent* aContent);
+
   inline ServoStyleSet* StyleSet() const {
     MOZ_ASSERT(PresContext()->StyleSet()->IsServo(),
                "ServoRestyleManager should only be used with a Servo-flavored "

layout/base/nsCSSFrameConstructor.cpp

@@ -4262,7 +4262,7 @@ nsCSSFrameConstructor::GetAnonymousContent(nsIContent* aParent,
   if (ServoStyleSet* styleSet = mPresShell->StyleSet()->GetAsServo()) {
     // Eagerly compute styles for the anonymous content tree.
     for (auto& info : aContent) {
-      styleSet->RestyleSubtree(info.mContent);
+      styleSet->RestyleSubtree(info.mContent, /* aForce = */ true);
     }
   }
 

layout/base/nsRefreshDriver.h

@@ -155,7 +155,7 @@ public:
    */
   bool AddStyleFlushObserver(nsIPresShell* aShell) {
     NS_ASSERTION(!mStyleFlushObservers.Contains(aShell),
-		 "Double-adding style flush observer");
+                 "Double-adding style flush observer");
     // We only get the cause for the first observer each frame because capturing
     // a stack is expensive. This is still useful if (1) you're trying to remove
     // all flushes for a particial frame or (2) the costly flush is triggered
@@ -173,7 +173,7 @@ public:
   }
   bool AddLayoutFlushObserver(nsIPresShell* aShell) {
     NS_ASSERTION(!IsLayoutFlushObserver(aShell),
-		 "Double-adding layout flush observer");
+                 "Double-adding layout flush observer");
     // We only get the cause for the first observer each frame because capturing
     // a stack is expensive. This is still useful if (1) you're trying to remove
     // all flushes for a particial frame or (2) the costly flush is triggered
@@ -193,7 +193,7 @@ public:
   }
   bool AddPresShellToInvalidateIfHidden(nsIPresShell* aShell) {
     NS_ASSERTION(!mPresShellsToInvalidateIfHidden.Contains(aShell),
-		 "Double-adding style flush observer");
+                 "Double-adding style flush observer");
     bool appended = mPresShellsToInvalidateIfHidden.AppendElement(aShell) != nullptr;
     EnsureTimerStarted();
     return appended;
@@ -288,7 +288,7 @@ public:
    * Check whether the given observer is an observer for the given flush type
    */
   bool IsRefreshObserver(nsARefreshObserver *aObserver,
-			   mozFlushType aFlushType);
+                         mozFlushType aFlushType);
 #endif
 
   /**

layout/style/ServoStyleSet.cpp

@@ -6,6 +6,7 @@
 
 #include "mozilla/ServoStyleSet.h"
 
+#include "mozilla/ServoRestyleManager.h"
 #include "nsCSSAnonBoxes.h"
 #include "nsCSSPseudoElements.h"
 #include "nsIDocumentInlines.h"
@@ -379,7 +380,12 @@ ServoStyleSet::HasStateDependentStyle(dom::Element* aElement,
 }
 
 void
-ServoStyleSet::RestyleSubtree(nsINode* aNode)
+ServoStyleSet::RestyleSubtree(nsINode* aNode, bool aForce)
 {
+  if (aForce) {
+    MOZ_ASSERT(aNode->IsContent());
+    ServoRestyleManager::DirtyTree(aNode->AsContent());
+  }
+
   Servo_RestyleSubtree(aNode, mRawSet.get());
 }

layout/style/ServoStyleSet.h

@@ -24,6 +24,7 @@ namespace dom {
 class Element;
 } // namespace dom
 class CSSStyleSheet;
+class ServoRestyleManager;
 class ServoStyleSheet;
 } // namespace mozilla
 class nsIDocument;
@@ -39,6 +40,7 @@ namespace mozilla {
  */
 class ServoStyleSet
 {
+  friend class ServoRestyleManager;
 public:
   ServoStyleSet();
 
@@ -116,7 +118,13 @@ public:
                                        dom::Element* aPseudoElement,
                                        EventStates aStateMask);
 
-  void RestyleSubtree(nsINode* aNode);
+  /**
+   * Restyles a whole subtree of nodes.
+   *
+   * The aForce parameter propagates the dirty bits down the subtree, and when
+   * used aNode needs to be nsIContent.
+   */
+  void RestyleSubtree(nsINode* aNode, bool aForce);
 
 private:
   already_AddRefed<nsStyleContext> GetContext(already_AddRefed<ServoComputedValues>,