1 files changed, 293 insertions, 0 deletions
diff --git a/accessible/base/AccAttributes.h b/accessible/base/AccAttributes.h
new file mode 100644
index 0000000000..0d7610b358
--- /dev/null
+++ b/accessible/base/AccAttributes.h
@@ -0,0 +1,293 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* 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/. */
+
+#ifndef AccAttributes_h_
+#define AccAttributes_h_
+
+#include "mozilla/ServoStyleConsts.h"
+#include "mozilla/a11y/AccGroupInfo.h"
+#include "mozilla/Variant.h"
+#include "nsTHashMap.h"
+#include "nsStringFwd.h"
+#include "mozilla/gfx/Matrix.h"
+
+class nsVariant;
+
+namespace IPC {
+template <typename T>
+struct ParamTraits;
+}  // namespace IPC
+
+namespace mozilla {
+
+namespace dom {
+class Element;
+}
+
+namespace a11y {
+
+struct FontSize {
+  int32_t mValue;
+
+  bool operator==(const FontSize& aOther) const {
+    return mValue == aOther.mValue;
+  }
+
+  bool operator!=(const FontSize& aOther) const {
+    return mValue != aOther.mValue;
+  }
+};
+
+struct Color {
+  nscolor mValue;
+
+  bool operator==(const Color& aOther) const { return mValue == aOther.mValue; }
+
+  bool operator!=(const Color& aOther) const { return mValue != aOther.mValue; }
+};
+
+// A special type. If an entry has a value of this type, it instructs the
+// target instance of an Update to remove the entry with the same key value.
+struct DeleteEntry {
+  DeleteEntry() : mValue(true) {}
+  bool mValue;
+
+  bool operator==(const DeleteEntry& aOther) const { return true; }
+
+  bool operator!=(const DeleteEntry& aOther) const { return false; }
+};
+
+class AccAttributes {
+  // Warning! An AccAttributes can contain another AccAttributes. This is
+  // intended for object and text attributes. However, the nested
+  // AccAttributes should never itself contain another AccAttributes, nor
+  // should it create a cycle. We don't do cycle collection here for
+  // performance reasons, so violating this rule will cause leaks!
+  using AttrValueType =
+      Variant<bool, float, double, int32_t, RefPtr<nsAtom>, nsTArray<int32_t>,
+              CSSCoord, FontSize, Color, DeleteEntry, UniquePtr<nsString>,
+              RefPtr<AccAttributes>, uint64_t, UniquePtr<AccGroupInfo>,
+              UniquePtr<gfx::Matrix4x4>, nsTArray<uint64_t>>;
+  static_assert(sizeof(AttrValueType) <= 16);
+  using AtomVariantMap = nsTHashMap<RefPtr<nsAtom>, AttrValueType>;
+
+ protected:
+  ~AccAttributes() = default;
+
+ public:
+  AccAttributes() = default;
+  AccAttributes(const AccAttributes&) = delete;
+  AccAttributes& operator=(const AccAttributes&) = delete;
+
+  NS_INLINE_DECL_REFCOUNTING(mozilla::a11y::AccAttributes)
+
+  template <typename T>
+  void SetAttribute(nsAtom* aAttrName, T&& aAttrValue) {
+    using ValType =
+        std::remove_const_t<std::remove_reference_t<decltype(aAttrValue)>>;
+    if constexpr (std::is_convertible_v<ValType, nsString>) {
+      static_assert(std::is_rvalue_reference_v<decltype(aAttrValue)>,
+                    "Please only move strings into this function. To make a "
+                    "copy, use SetAttributeStringCopy.");
+      UniquePtr<nsString> value = MakeUnique<nsString>(std::move(aAttrValue));
+      mData.InsertOrUpdate(aAttrName, AsVariant(std::move(value)));
+    } else if constexpr (std::is_same_v<ValType, gfx::Matrix4x4>) {
+      UniquePtr<gfx::Matrix4x4> value = MakeUnique<gfx::Matrix4x4>(aAttrValue);
+      mData.InsertOrUpdate(aAttrName, AsVariant(std::move(value)));
+    } else if constexpr (std::is_same_v<ValType, AccGroupInfo*>) {
+      UniquePtr<AccGroupInfo> value(aAttrValue);
+      mData.InsertOrUpdate(aAttrName, AsVariant(std::move(value)));
+    } else if constexpr (std::is_convertible_v<ValType, nsAtom*>) {
+      mData.InsertOrUpdate(aAttrName, AsVariant(RefPtr<nsAtom>(aAttrValue)));
+    } else {
+      mData.InsertOrUpdate(aAttrName, AsVariant(std::forward<T>(aAttrValue)));
+    }
+  }
+
+  void SetAttributeStringCopy(nsAtom* aAttrName, nsString aAttrValue) {
+    SetAttribute(aAttrName, std::move(aAttrValue));
+  }
+
+  template <typename T>
+  Maybe<const T&> GetAttribute(nsAtom* aAttrName) const {
+    if (auto value = mData.Lookup(aAttrName)) {
+      if constexpr (std::is_same_v<nsString, T>) {
+        if (value->is<UniquePtr<nsString>>()) {
+          const T& val = *(value->as<UniquePtr<nsString>>().get());
+          return SomeRef(val);
+        }
+      } else if constexpr (std::is_same_v<gfx::Matrix4x4, T>) {
+        if (value->is<UniquePtr<gfx::Matrix4x4>>()) {
+          const T& val = *(value->as<UniquePtr<gfx::Matrix4x4>>());
+          return SomeRef(val);
+        }
+      } else {
+        if (value->is<T>()) {
+          const T& val = value->as<T>();
+          return SomeRef(val);
+        }
+      }
+    }
+    return Nothing();
+  }
+
+  template <typename T>
+  RefPtr<const T> GetAttributeRefPtr(nsAtom* aAttrName) const {
+    if (auto value = mData.Lookup(aAttrName)) {
+      if (value->is<RefPtr<T>>()) {
+        RefPtr<const T> ref = value->as<RefPtr<T>>();
+        return ref;
+      }
+    }
+    return nullptr;
+  }
+
+  template <typename T>
+  Maybe<T&> GetMutableAttribute(nsAtom* aAttrName) const {
+    static_assert(std::is_same_v<nsTArray<int32_t>, T> ||
+                      std::is_same_v<nsTArray<uint64_t>, T>,
+                  "Only arrays should be mutable attributes");
+    if (auto value = mData.Lookup(aAttrName)) {
+      if (value->is<T>()) {
+        T& val = value->as<T>();
+        return SomeRef(val);
+      }
+    }
+    return Nothing();
+  }
+
+  // Get stringified value
+  bool GetAttribute(nsAtom* aAttrName, nsAString& aAttrValue) const;
+
+  bool HasAttribute(nsAtom* aAttrName) const {
+    return mData.Contains(aAttrName);
+  }
+
+  bool Remove(nsAtom* aAttrName) { return mData.Remove(aAttrName); }
+
+  uint32_t Count() const { return mData.Count(); }
+
+  // Update one instance with the entries in another. The supplied AccAttributes
+  // will be emptied.
+  void Update(AccAttributes* aOther);
+
+  /**
+   * Return true if all the attributes in this instance are equal to all the
+   * attributes in another instance.
+   */
+  bool Equal(const AccAttributes* aOther) const;
+
+  /**
+   * Copy attributes from this instance to another instance.
+   * This should only be used in very specific cases; e.g. merging two sets of
+   * cached attributes without modifying the cache. It can only copy simple
+   * value types; e.g. it can't copy array values. Attempting to copy an
+   * AccAttributes with uncopyable values will cause an assertion.
+   */
+  void CopyTo(AccAttributes* aDest) const;
+
+  // An entry class for our iterator.
+  class Entry {
+   public:
+    Entry(nsAtom* aAttrName, const AttrValueType* aAttrValue)
+        : mName(aAttrName), mValue(aAttrValue) {}
+
+    nsAtom* Name() const { return mName; }
+
+    template <typename T>
+    Maybe<const T&> Value() const {
+      if constexpr (std::is_same_v<nsString, T>) {
+        if (mValue->is<UniquePtr<nsString>>()) {
+          const T& val = *(mValue->as<UniquePtr<nsString>>().get());
+          return SomeRef(val);
+        }
+      } else if constexpr (std::is_same_v<gfx::Matrix4x4, T>) {
+        if (mValue->is<UniquePtr<gfx::Matrix4x4>>()) {
+          const T& val = *(mValue->as<UniquePtr<gfx::Matrix4x4>>());
+          return SomeRef(val);
+        }
+      } else {
+        if (mValue->is<T>()) {
+          const T& val = mValue->as<T>();
+          return SomeRef(val);
+        }
+      }
+      return Nothing();
+    }
+
+    void NameAsString(nsString& aName) const {
+      mName->ToString(aName);
+      if (StringBeginsWith(aName, u"aria-"_ns)) {
+        // Found 'aria-'
+        aName.ReplaceLiteral(0, 5, u"");
+      }
+    }
+
+    void ValueAsString(nsAString& aValueString) const {
+      StringFromValueAndName(mName, *mValue, aValueString);
+    }
+
+    // Size of the pair in the hash table.
+    size_t SizeOfExcludingThis(MallocSizeOf aMallocSizeOf);
+
+   private:
+    nsAtom* mName;
+    const AttrValueType* mValue;
+
+    friend class AccAttributes;
+  };
+
+  class Iterator {
+   public:
+    explicit Iterator(AtomVariantMap::const_iterator aIter)
+        : mHashIterator(aIter) {}
+
+    Iterator() = delete;
+    Iterator(const Iterator&) = delete;
+    Iterator& operator=(const Iterator&) = delete;
+
+    bool operator!=(const Iterator& aOther) const {
+      return mHashIterator != aOther.mHashIterator;
+    }
+
+    Iterator& operator++() {
+      mHashIterator++;
+      return *this;
+    }
+
+    Entry operator*() const {
+      auto& entry = *mHashIterator;
+      return Entry(entry.GetKey(), &entry.GetData());
+    }
+
+   private:
+    AtomVariantMap::const_iterator mHashIterator;
+  };
+
+  friend class Iterator;
+
+  Iterator begin() const { return Iterator(mData.begin()); }
+  Iterator end() const { return Iterator(mData.end()); }
+
+#ifdef A11Y_LOG
+  static void DebugPrint(const char* aPrefix, const AccAttributes& aAttributes);
+#endif
+
+  size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf);
+
+ private:
+  static void StringFromValueAndName(nsAtom* aAttrName,
+                                     const AttrValueType& aValue,
+                                     nsAString& aValueString);
+
+  AtomVariantMap mData;
+
+  friend struct IPC::ParamTraits<AccAttributes*>;
+};
+
+}  // namespace a11y
+}  // namespace mozilla
+
+#endif