Add a WebDocument::watchCssSelectors(selectors)

Source/core/dom/Element.cpp

Index: Source/core/dom/Element.cpp
diff --git a/Source/core/dom/Element.cpp b/Source/core/dom/Element.cpp
index ce5e91a04f284c071f7fabb080953e601ae0b4b1..8cdfa4a77ecd7c653cc60df687592be13b5bf016 100644
--- a/Source/core/dom/Element.cpp
+++ b/Source/core/dom/Element.cpp
@@ -44,6 +44,7 @@
 #include "core/css/resolver/StyleResolver.h"
 #include "core/dom/Attr.h"
 #include "core/dom/Attribute.h"
+#include "core/dom/CSSSelectorWatch.h"
 #include "core/dom/ClientRect.h"
 #include "core/dom/ClientRectList.h"
 #include "core/dom/CustomElement.h"
@@ -1326,6 +1327,8 @@ void Element::attach(const AttachContext& context)
 
     NodeRenderingContext(this, context.resolvedStyle).createRendererForElementIfNeeded();
 
+    updateCallbackSelectors(Add);
+
     createPseudoElementIfNeeded(BEFORE);
 
     // When a shadow root exists, it does the work of attaching the children.
@@ -1367,6 +1370,7 @@ void Element::detach(const AttachContext& context)
     WidgetHierarchyUpdatesSuspensionScope suspendWidgetHierarchyUpdates;
     unregisterNamedFlowContentNode();
     cancelFocusAppearanceUpdate();
+    updateCallbackSelectors(Remove);
     if (hasRareData()) {
         ElementRareData* data = elementRareData();
         data->setPseudoElement(BEFORE, 0);
@@ -1450,6 +1454,24 @@ bool Element::recalcStyle(StyleChange change)
     if (hasCustomStyleCallbacks())
         willRecalcStyle(change);
 
+    class SelectorWatchUpdater {

[esprehn, 2013/09/04 06:08:28]

Don't put classes inside methods. This needs to be at the top of the file or in
its own file.

[Jeffrey Yasskin, 2013/09/12 22:09:59]

It's no longer necessary. :)

+    public:
+        SelectorWatchUpdater(Element* element)
+            : m_element(element)
+        {
+            m_element->updateCallbackSelectors(Remove);

[esprehn, 2013/09/04 06:08:28]

This is not right, why are you removing and adding on every recalcStyle? You do
this on every element as it walks down the tree, even if the style is identical.

I think you want recalcOwnStyle() in here and you want to only mess around with
this if the style changed?

[Jeffrey Yasskin, 2013/09/12 22:09:59]

Yep, using recalcOwnStyle() cleaned this up a lot.

+        }
+
+        ~SelectorWatchUpdater()
+        {
+            m_element->updateCallbackSelectors(Add);
+        }
+
+    private:
+        Element* const m_element;
+    };
+    SelectorWatchUpdater watchUpdater(this);
+
     if (hasRareData() && (change > NoChange || needsStyleRecalc())) {
         ElementRareData* data = elementRareData();
         data->resetStyleState();
@@ -2435,6 +2457,33 @@ void Element::cancelFocusAppearanceUpdate()
         document()->cancelFocusAppearanceUpdate();
 }
 
+void Element::updateCallbackSelectors(AddOrRemove addOrRemove)
+{
+    if (!renderStyle())
+        return;

[esprehn, 2013/09/04 06:08:28]

Don't call RenderStyle repeatedly, you want to call it once and save the value.

[Jeffrey Yasskin, 2013/09/12 22:09:59]

Obsolete. :)

+    const Vector<String>& callbackSelectors = renderStyle()->callbackSelectors();
+    if (callbackSelectors.isEmpty())

[esprehn, 2013/09/04 06:08:28]

The check should be outside the function call since it'll be inline simple
checks unless you have the "slow stuff"


RenderStyle* style = renderStyle()
if (style && style->hasCallbackSelectors())
  doSomethingHere();

[Jeffrey Yasskin, 2013/09/12 22:09:59]

Done.

+        return;
+
+    CSSSelectorWatch* selectorWatch = CSSSelectorWatch::from(document());
+    switch (addOrRemove) {
+    case Add: {
+        ElementRareData* rareData = ensureElementRareData();
+        if (!rareData->renderStyleWatchedSelectorsRepresentedInSelectorWatch()) {
+            selectorWatch->addSelectorMatches(callbackSelectors);
+            rareData->setRenderStyleWatchedSelectorsRepresentedInSelectorWatch(true);
+        }
+        break;

[esprehn, 2013/09/04 06:08:28]

These should be two separate methods and get rid of the enum and switch.

[Jeffrey Yasskin, 2013/09/12 22:09:59]

Refactored away.

+    }
+    case Remove:
+        if (hasRareData() && elementRareData()->renderStyleWatchedSelectorsRepresentedInSelectorWatch()) {
+            selectorWatch->removeSelectorMatches(callbackSelectors);
+            elementRareData()->setRenderStyleWatchedSelectorsRepresentedInSelectorWatch(false);
+        }
+        break;
+    }
+}
+
 void Element::normalizeAttributes()
 {
     if (!hasAttributes())