third_party/WebKit/Source/core/dom/PseudoElement.cpp

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  26
  27 #include "config.h"
  28 #include "core/dom/PseudoElement.h"
  29
  30 #include "core/dom/FirstLetterPseudoElement.h"
  31 #include "core/frame/UseCounter.h"
  32 #include "core/inspector/InspectorInstrumentation.h"
  33 #include "core/layout/LayoutObject.h"
  34 #include "core/layout/LayoutQuote.h"
  35 #include "core/style/ContentData.h"
  36
  37 namespace blink {
  38
  39 PassRefPtrWillBeRawPtr<PseudoElement> PseudoElement::create(Element* parent, PseudoId pseudoId)
  40 {
  41     return adoptRefWillBeNoop(new PseudoElement(parent, pseudoId));
  42 }
  43
  44 const QualifiedName& pseudoElementTagName(PseudoId pseudoId)
  45 {
  46     switch (pseudoId) {
  47     case AFTER: {
  48         DEFINE_STATIC_LOCAL(QualifiedName, after, (nullAtom, "<pseudo:after>", nullAtom));
  49         return after;
  50     }
  51     case BEFORE: {
  52         DEFINE_STATIC_LOCAL(QualifiedName, before, (nullAtom, "<pseudo:before>", nullAtom));
  53         return before;
  54     }
  55     case BACKDROP: {
  56         DEFINE_STATIC_LOCAL(QualifiedName, backdrop, (nullAtom, "<pseudo:backdrop>", nullAtom));
  57         return backdrop;
  58     }
  59     case FIRST_LETTER: {
  60         DEFINE_STATIC_LOCAL(QualifiedName, firstLetter, (nullAtom, "<pseudo:first-letter>", nullAtom));
  61         return firstLetter;
  62     }
  63     default: {
  64         ASSERT_NOT_REACHED();
  65     }
  66     }
  67     DEFINE_STATIC_LOCAL(QualifiedName, name, (nullAtom, "<pseudo>", nullAtom));
  68     return name;
  69 }
  70
  71 String PseudoElement::pseudoElementNameForEvents(PseudoId pseudoId)
  72 {
  73     DEFINE_STATIC_LOCAL(const String, after, ("::after"));
  74     DEFINE_STATIC_LOCAL(const String, before, ("::before"));
  75     switch (pseudoId) {
  76     case AFTER:
  77         return after;
  78     case BEFORE:
  79         return before;
  80     default:
  81         return emptyString();
  82     }
  83 }
  84
  85 PseudoElement::PseudoElement(Element* parent, PseudoId pseudoId)
  86     : Element(pseudoElementTagName(pseudoId), &parent->document(), CreateElement)
  87     , m_pseudoId(pseudoId)
  88 {
  89     ASSERT(pseudoId != NOPSEUDO);
  90     parent->treeScope().adoptIfNeeded(*this);
  91     setParentOrShadowHostNode(parent);
  92     setHasCustomStyleCallbacks();
  93     if ((pseudoId == BEFORE || pseudoId == AFTER) && parent->hasTagName(HTMLNames::inputTag))
  94         UseCounter::count(parent->document(), UseCounter::PseudoBeforeAfterForInputElement);
  95 }
  96
  97 PassRefPtr<ComputedStyle> PseudoElement::customStyleForLayoutObject()
  98 {
  99     return parentOrShadowHostElement()->layoutObject()->getCachedPseudoStyle(m_pseudoId);
 100 }
 101
 102 void PseudoElement::dispose()
 103 {
 104     ASSERT(parentOrShadowHostElement());
 105
 106     InspectorInstrumentation::pseudoElementDestroyed(this);
 107
 108     ASSERT(!nextSibling());
 109     ASSERT(!previousSibling());
 110
 111     detach();
 112     RefPtrWillBeRawPtr<Element> parent = parentOrShadowHostElement();
 113     document().adoptIfNeeded(*this);
 114     setParentOrShadowHostNode(0);
 115     removedFrom(parent.get());
 116 }
 117
 118 void PseudoElement::attach(const AttachContext& context)
 119 {
 120     ASSERT(!layoutObject());
 121
 122     Element::attach(context);
 123
 124     LayoutObject* layoutObject = this->layoutObject();
 125     if (!layoutObject)
 126         return;
 127
 128     ComputedStyle& style = layoutObject->mutableStyleRef();
 129     if (style.styleType() != BEFORE && style.styleType() != AFTER)
 130         return;
 131     ASSERT(style.contentData());
 132
 133     for (const ContentData* content = style.contentData(); content; content = content->next()) {
 134         LayoutObject* child = content->createLayoutObject(document(), style);
 135         if (layoutObject->isChildAllowed(child, style)) {
 136             layoutObject->addChild(child);
 137             if (child->isQuote())
 138                 toLayoutQuote(child)->attachQuote();
 139         } else {
 140             child->destroy();
 141         }
 142     }
 143 }
 144
 145 bool PseudoElement::layoutObjectIsNeeded(const ComputedStyle& style)
 146 {
 147     return pseudoElementLayoutObjectIsNeeded(&style);
 148 }
 149
 150 void PseudoElement::didRecalcStyle(StyleRecalcChange)
 151 {
 152     if (!layoutObject())
 153         return;
 154
 155     // The layoutObjects inside pseudo elements are anonymous so they don't get notified of recalcStyle and must have
 156     // the style propagated downward manually similar to LayoutObject::propagateStyleToAnonymousChildren.
 157     LayoutObject* layoutObject = this->layoutObject();
 158     for (LayoutObject* child = layoutObject->nextInPreOrder(layoutObject); child; child = child->nextInPreOrder(layoutObject)) {
 159         // We only manage the style for the generated content items.
 160         if (!child->isText() && !child->isQuote() && !child->isImage())
 161             continue;
 162
 163         child->setPseudoStyle(layoutObject->mutableStyle());
 164     }
 165 }
 166
 167 // With PseudoElements the DOM tree and Layout tree can differ. When you attach
 168 // a, first-letter for example, into the DOM we walk down the Layout
 169 // tree to find the correct insertion point for the LayoutObject. But, this
 170 // means if we ask for the parentOrShadowHost Node from the first-letter
 171 // pseudo element we will get some arbitrary ancestor of the LayoutObject.
 172 //
 173 // For hit testing, we need the parent Node of the LayoutObject for the
 174 // first-letter pseudo element. So, by walking up the Layout tree we know
 175 // we will get the parent and not some other ancestor.
 176 Node* PseudoElement::findAssociatedNode() const
 177 {
 178     // The ::backdrop element is parented to the LayoutView, not to the node
 179     // that it's associated with. We need to make sure ::backdrop sends the
 180     // events to the parent node correctly.
 181     if (pseudoId() == BACKDROP)
 182         return parentOrShadowHostNode();
 183
 184     ASSERT(layoutObject());
 185     ASSERT(layoutObject()->parent());
 186
 187     // We can have any number of anonymous layout objects inserted between
 188     // us and our parent so make sure we skip over them.
 189     LayoutObject* ancestor = layoutObject()->parent();
 190     while (ancestor->isAnonymous() || (ancestor->node() && ancestor->node()->isPseudoElement())) {
 191         ASSERT(ancestor->parent());
 192         ancestor = ancestor->parent();
 193     }
 194     return ancestor->node();
 195 }
 196
 197 } // namespace