1 files changed, 230 insertions, 0 deletions
diff --git a/dom/base/IdentifierMapEntry.h b/dom/base/IdentifierMapEntry.h
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+++ b/dom/base/IdentifierMapEntry.h
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+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* 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/. */
+
+/*
+ * Entry for the Document or ShadowRoot's identifier map.
+ */
+
+#ifndef mozilla_IdentifierMapEntry_h
+#define mozilla_IdentifierMapEntry_h
+
+#include <utility>
+
+#include "PLDHashTable.h"
+#include "mozilla/MemoryReporting.h"
+#include "mozilla/UniquePtr.h"
+#include "mozilla/dom/TreeOrderedArray.h"
+#include "nsAtom.h"
+#include "nsCOMPtr.h"
+#include "nsContentList.h"
+#include "nsHashKeys.h"
+#include "nsTArray.h"
+#include "nsTHashtable.h"
+
+class nsIContent;
+class nsINode;
+
+namespace mozilla {
+namespace dom {
+class Document;
+class Element;
+}  // namespace dom
+
+/**
+ * Right now our identifier map entries contain information for 'name'
+ * and 'id' mappings of a given string. This is so that
+ * nsHTMLDocument::ResolveName only has to do one hash lookup instead
+ * of two. It's not clear whether this still matters for performance.
+ *
+ * We also store the document.all result list here. This is mainly so that
+ * when all elements with the given ID are removed and we remove
+ * the ID's IdentifierMapEntry, the document.all result is released too.
+ * Perhaps the document.all results should have their own hashtable
+ * in nsHTMLDocument.
+ */
+class IdentifierMapEntry : public PLDHashEntryHdr {
+  typedef dom::Document Document;
+  typedef dom::Element Element;
+
+  /**
+   * @see Document::IDTargetObserver, this is just here to avoid include hell.
+   */
+  typedef bool (*IDTargetObserver)(Element* aOldElement, Element* aNewelement,
+                                   void* aData);
+
+ public:
+  // We use DependentAtomOrString as our external key interface.  This allows
+  // consumers to use an nsAString, for example, without forcing a copy.
+  struct DependentAtomOrString final {
+    MOZ_IMPLICIT DependentAtomOrString(nsAtom* aAtom)
+        : mAtom(aAtom), mString(nullptr) {}
+    MOZ_IMPLICIT DependentAtomOrString(const nsAString& aString)
+        : mAtom(nullptr), mString(&aString) {}
+    DependentAtomOrString(const DependentAtomOrString& aOther) = default;
+
+    nsAtom* mAtom;
+    const nsAString* mString;
+  };
+
+  typedef const DependentAtomOrString& KeyType;
+  typedef const DependentAtomOrString* KeyTypePointer;
+
+  explicit IdentifierMapEntry(const DependentAtomOrString* aKey);
+  IdentifierMapEntry(IdentifierMapEntry&& aOther) = default;
+  ~IdentifierMapEntry() = default;
+
+  nsString GetKeyAsString() const {
+    if (mKey.mAtom) {
+      return nsAtomString(mKey.mAtom);
+    }
+
+    return mKey.mString;
+  }
+
+  bool KeyEquals(const KeyTypePointer aOtherKey) const {
+    if (mKey.mAtom) {
+      if (aOtherKey->mAtom) {
+        return mKey.mAtom == aOtherKey->mAtom;
+      }
+
+      return mKey.mAtom->Equals(*aOtherKey->mString);
+    }
+
+    if (aOtherKey->mAtom) {
+      return aOtherKey->mAtom->Equals(mKey.mString);
+    }
+
+    return mKey.mString.Equals(*aOtherKey->mString);
+  }
+
+  static KeyTypePointer KeyToPointer(KeyType aKey) { return &aKey; }
+
+  static PLDHashNumber HashKey(const KeyTypePointer aKey) {
+    return aKey->mAtom ? aKey->mAtom->hash() : HashString(*aKey->mString);
+  }
+
+  enum { ALLOW_MEMMOVE = false };
+
+  void AddNameElement(nsINode* aDocument, Element* aElement);
+  void RemoveNameElement(Element* aElement);
+  bool IsEmpty();
+  nsBaseContentList* GetNameContentList() { return mNameContentList; }
+  bool HasNameElement() const;
+
+  /**
+   * Returns the element if we know the element associated with this
+   * id. Otherwise returns null.
+   */
+  Element* GetIdElement() { return mIdContentList->SafeElementAt(0); }
+
+  /**
+   * Returns the list of all elements associated with this id.
+   */
+  const nsTArray<Element*>& GetIdElements() const { return mIdContentList; }
+
+  /**
+   * If this entry has a non-null image element set (using SetImageElement),
+   * the image element will be returned, otherwise the same as GetIdElement().
+   */
+  Element* GetImageIdElement() {
+    return mImageElement ? mImageElement.get() : GetIdElement();
+  }
+
+  /**
+   * This can fire ID change callbacks.
+   */
+  void AddIdElement(Element* aElement);
+  /**
+   * This can fire ID change callbacks.
+   */
+  void RemoveIdElement(Element* aElement);
+  /**
+   * Set the image element override for this ID. This will be returned by
+   * GetIdElement(true) if non-null.
+   */
+  void SetImageElement(Element* aElement);
+  bool HasIdElementExposedAsHTMLDocumentProperty();
+
+  bool HasContentChangeCallback() { return mChangeCallbacks != nullptr; }
+  void AddContentChangeCallback(IDTargetObserver aCallback, void* aData,
+                                bool aForImage);
+  void RemoveContentChangeCallback(IDTargetObserver aCallback, void* aData,
+                                   bool aForImage);
+
+  /**
+   * Remove all elements and notify change listeners.
+   */
+  void ClearAndNotify();
+
+  void Traverse(nsCycleCollectionTraversalCallback* aCallback);
+
+  struct ChangeCallback {
+    IDTargetObserver mCallback;
+    void* mData;
+    bool mForImage;
+  };
+
+  struct ChangeCallbackEntry : public PLDHashEntryHdr {
+    typedef const ChangeCallback KeyType;
+    typedef const ChangeCallback* KeyTypePointer;
+
+    explicit ChangeCallbackEntry(const ChangeCallback* aKey) : mKey(*aKey) {}
+    ChangeCallbackEntry(ChangeCallbackEntry&& aOther)
+        : PLDHashEntryHdr(std::move(aOther)), mKey(std::move(aOther.mKey)) {}
+
+    KeyType GetKey() const { return mKey; }
+    bool KeyEquals(KeyTypePointer aKey) const {
+      return aKey->mCallback == mKey.mCallback && aKey->mData == mKey.mData &&
+             aKey->mForImage == mKey.mForImage;
+    }
+
+    static KeyTypePointer KeyToPointer(KeyType& aKey) { return &aKey; }
+    static PLDHashNumber HashKey(KeyTypePointer aKey) {
+      return HashGeneric(aKey->mCallback, aKey->mData);
+    }
+    enum { ALLOW_MEMMOVE = true };
+
+    ChangeCallback mKey;
+  };
+
+  size_t SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const;
+
+ private:
+  // We use an OwningAtomOrString as our internal key storage.  It needs to own
+  // the key string, whether in atom or string form.
+  struct OwningAtomOrString final {
+    OwningAtomOrString(const OwningAtomOrString& aOther) = delete;
+    OwningAtomOrString(OwningAtomOrString&& aOther) = default;
+
+    explicit OwningAtomOrString(const DependentAtomOrString& aOther)
+        // aOther may have a null mString, so jump through a bit of a hoop in
+        // that case.  I wish there were a way to just default-initialize
+        // mString in that situation...  We could also make mString not const
+        // and only assign to it if aOther.mString is not null, but having it be
+        // const is nice.
+        : mAtom(aOther.mAtom),
+          mString(aOther.mString ? *aOther.mString : u""_ns) {}
+
+    RefPtr<nsAtom> mAtom;
+    nsString mString;
+  };
+
+  IdentifierMapEntry(const IdentifierMapEntry& aOther) = delete;
+  IdentifierMapEntry& operator=(const IdentifierMapEntry& aOther) = delete;
+
+  void FireChangeCallbacks(Element* aOldElement, Element* aNewElement,
+                           bool aImageOnly = false);
+
+  OwningAtomOrString mKey;
+  dom::TreeOrderedArray<Element> mIdContentList;
+  RefPtr<nsBaseContentList> mNameContentList;
+  UniquePtr<nsTHashtable<ChangeCallbackEntry> > mChangeCallbacks;
+  RefPtr<Element> mImageElement;
+};
+
+}  // namespace mozilla
+
+#endif  // #ifndef mozilla_IdentifierMapEntry_h