1 files changed, 304 insertions, 0 deletions
diff --git a/layout/style/nsCSSPropertyIDSet.h b/layout/style/nsCSSPropertyIDSet.h
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+++ b/layout/style/nsCSSPropertyIDSet.h
@@ -0,0 +1,304 @@
+/* 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/. */
+
+/* bit vectors for sets of CSS properties */
+
+#ifndef nsCSSPropertyIDSet_h__
+#define nsCSSPropertyIDSet_h__
+
+#include <initializer_list>
+#include <limits.h>  // for CHAR_BIT
+#include <ostream>
+
+#include "mozilla/ArrayUtils.h"
+// For COMPOSITOR_ANIMATABLE_PROPERTY_LIST and
+// COMPOSITOR_ANIMATABLE_PROPERTY_LIST_LENGTH
+#include "mozilla/AnimatedPropertyID.h"
+#include "mozilla/CompositorAnimatableProperties.h"
+#include "nsCSSProps.h"  // For operator<< for nsCSSPropertyID
+#include "nsCSSPropertyID.h"
+
+/**
+ * nsCSSPropertyIDSet maintains a set of non-shorthand CSS properties.  In
+ * other words, for each longhand CSS property we support, it has a bit
+ * for whether that property is in the set.
+ */
+class nsCSSPropertyIDSet {
+ public:
+  constexpr nsCSSPropertyIDSet() : mProperties{0} {}
+  // auto-generated copy-constructor OK
+
+  explicit constexpr nsCSSPropertyIDSet(
+      std::initializer_list<nsCSSPropertyID> aProperties)
+      : mProperties{0} {
+    for (auto property : aProperties) {
+      size_t p = property;
+      mProperties[p / kBitsInChunk] |= property_set_type(1)
+                                       << (p % kBitsInChunk);
+    }
+  }
+
+  void AssertInSetRange(nsCSSPropertyID aProperty) const {
+    MOZ_DIAGNOSTIC_ASSERT(
+        0 <= aProperty && aProperty < eCSSProperty_COUNT_no_shorthands,
+        "out of bounds");
+  }
+
+  // Conversion of aProperty to |size_t| after AssertInSetRange
+  // lets the compiler generate significantly tighter code.
+
+  void AddProperty(nsCSSPropertyID aProperty) {
+    AssertInSetRange(aProperty);
+    size_t p = aProperty;
+    mProperties[p / kBitsInChunk] |= property_set_type(1) << (p % kBitsInChunk);
+  }
+
+  void RemoveProperty(nsCSSPropertyID aProperty) {
+    AssertInSetRange(aProperty);
+    size_t p = aProperty;
+    mProperties[p / kBitsInChunk] &=
+        ~(property_set_type(1) << (p % kBitsInChunk));
+  }
+
+  bool HasProperty(const mozilla::AnimatedPropertyID& aProperty) const {
+    return !aProperty.IsCustom() && HasProperty(aProperty.mID);
+  }
+
+  bool HasProperty(nsCSSPropertyID aProperty) const {
+    AssertInSetRange(aProperty);
+    size_t p = aProperty;
+    return (mProperties[p / kBitsInChunk] &
+            (property_set_type(1) << (p % kBitsInChunk))) != 0;
+  }
+
+  // Returns an nsCSSPropertyIDSet including all properties that can be run
+  // on the compositor.
+  static constexpr nsCSSPropertyIDSet CompositorAnimatables() {
+    return nsCSSPropertyIDSet(COMPOSITOR_ANIMATABLE_PROPERTY_LIST);
+  }
+
+  static constexpr size_t CompositorAnimatableCount() {
+    return COMPOSITOR_ANIMATABLE_PROPERTY_LIST_LENGTH;
+  }
+
+  static constexpr size_t CompositorAnimatableDisplayItemCount() {
+    // We have 3 individual transforms and 5 motion path properties, and they
+    // also use DisplayItemType::TYPE_TRANSFORM.
+    return COMPOSITOR_ANIMATABLE_PROPERTY_LIST_LENGTH - 8;
+  }
+
+  static constexpr nsCSSPropertyIDSet CSSTransformProperties() {
+    return nsCSSPropertyIDSet{eCSSProperty_transform, eCSSProperty_translate,
+                              eCSSProperty_rotate, eCSSProperty_scale};
+  }
+
+  static constexpr nsCSSPropertyIDSet MotionPathProperties() {
+    return nsCSSPropertyIDSet{
+        eCSSProperty_offset_path, eCSSProperty_offset_distance,
+        eCSSProperty_offset_rotate, eCSSProperty_offset_anchor,
+        eCSSProperty_offset_position};
+  }
+
+  static constexpr nsCSSPropertyIDSet TransformLikeProperties() {
+    return nsCSSPropertyIDSet{
+        eCSSProperty_transform,      eCSSProperty_translate,
+        eCSSProperty_rotate,         eCSSProperty_scale,
+        eCSSProperty_offset_path,    eCSSProperty_offset_distance,
+        eCSSProperty_offset_rotate,  eCSSProperty_offset_anchor,
+        eCSSProperty_offset_position};
+  }
+
+  static constexpr nsCSSPropertyIDSet OpacityProperties() {
+    return nsCSSPropertyIDSet{eCSSProperty_opacity};
+  }
+
+  bool Intersects(const nsCSSPropertyIDSet& aOther) const {
+    for (size_t i = 0; i < mozilla::ArrayLength(mProperties); ++i) {
+      if (mProperties[i] & aOther.mProperties[i]) {
+        return true;
+      }
+    }
+    return false;
+  }
+
+  void Empty() { memset(mProperties, 0, sizeof(mProperties)); }
+
+  void AssertIsEmpty(const char* aText) const {
+    for (size_t i = 0; i < mozilla::ArrayLength(mProperties); ++i) {
+      NS_ASSERTION(mProperties[i] == 0, aText);
+    }
+  }
+
+  bool Equals(const nsCSSPropertyIDSet& aOther) const {
+    return mozilla::ArrayEqual(mProperties, aOther.mProperties);
+  }
+
+  bool IsEmpty() const {
+    for (size_t i = 0; i < mozilla::ArrayLength(mProperties); ++i) {
+      if (mProperties[i] != 0) {
+        return false;
+      }
+    }
+    return true;
+  }
+
+  bool IsSubsetOf(const nsCSSPropertyIDSet& aOther) const {
+    return this->Intersect(aOther).Equals(*this);
+  }
+
+  // Return a new nsCSSPropertyIDSet which is the inverse of this set.
+  nsCSSPropertyIDSet Inverse() const {
+    nsCSSPropertyIDSet result;
+    for (size_t i = 0; i < mozilla::ArrayLength(mProperties); ++i) {
+      result.mProperties[i] = ~mProperties[i];
+    }
+    return result;
+  }
+
+  // Returns a new nsCSSPropertyIDSet with all properties that are both in
+  // this set and |aOther|.
+  nsCSSPropertyIDSet Intersect(const nsCSSPropertyIDSet& aOther) const {
+    nsCSSPropertyIDSet result;
+    for (size_t i = 0; i < mozilla::ArrayLength(mProperties); ++i) {
+      result.mProperties[i] = mProperties[i] & aOther.mProperties[i];
+    }
+    return result;
+  }
+
+  // Return a new nsCSSPropertyIDSet with all properties that are in either
+  // this set or |aOther| but not both.
+  nsCSSPropertyIDSet Xor(const nsCSSPropertyIDSet& aOther) const {
+    nsCSSPropertyIDSet result;
+    for (size_t i = 0; i < mozilla::ArrayLength(mProperties); ++i) {
+      result.mProperties[i] = mProperties[i] ^ aOther.mProperties[i];
+    }
+    return result;
+  }
+
+  nsCSSPropertyIDSet& operator|=(const nsCSSPropertyIDSet& aOther) {
+    for (size_t i = 0; i < mozilla::ArrayLength(mProperties); ++i) {
+      mProperties[i] |= aOther.mProperties[i];
+    }
+    return *this;
+  }
+
+ private:
+  typedef unsigned long property_set_type;
+
+ public:
+  // number of bits in |property_set_type|.
+  static const size_t kBitsInChunk = sizeof(property_set_type) * CHAR_BIT;
+  // number of |property_set_type|s in the set
+  static const size_t kChunkCount =
+      (eCSSProperty_COUNT_no_shorthands + kBitsInChunk - 1) / kBitsInChunk;
+
+  /*
+   * For fast enumeration of all the bits that are set, callers can
+   * check each chunk against zero (since in normal cases few bits are
+   * likely to be set).
+   */
+  bool HasPropertyInChunk(size_t aChunk) const {
+    return mProperties[aChunk] != 0;
+  }
+  bool HasPropertyAt(size_t aChunk, size_t aBit) const {
+    return (mProperties[aChunk] & (property_set_type(1) << aBit)) != 0;
+  }
+  static nsCSSPropertyID CSSPropertyAt(size_t aChunk, size_t aBit) {
+    return nsCSSPropertyID(aChunk * kBitsInChunk + aBit);
+  }
+
+  // Iterator for use in range-based for loops
+  class Iterator {
+   public:
+    Iterator(Iterator&& aOther)
+        : mPropertySet(aOther.mPropertySet),
+          mChunk(aOther.mChunk),
+          mBit(aOther.mBit) {}
+
+    static Iterator BeginIterator(const nsCSSPropertyIDSet& aPropertySet) {
+      Iterator result(aPropertySet);
+
+      // Search for the first property.
+      // Unsigned integer overflow is defined so the following is safe.
+      result.mBit = -1;
+      ++result;
+
+      return result;
+    }
+
+    static Iterator EndIterator(const nsCSSPropertyIDSet& aPropertySet) {
+      Iterator result(aPropertySet);
+      result.mChunk = kChunkCount;
+      result.mBit = 0;
+      return result;
+    }
+
+    bool operator!=(const Iterator& aOther) const {
+      return mChunk != aOther.mChunk || mBit != aOther.mBit;
+    }
+
+    Iterator& operator++() {
+      MOZ_ASSERT(mChunk < kChunkCount, "Should not iterate beyond end");
+
+      do {
+        mBit++;
+      } while (mBit < kBitsInChunk &&
+               !mPropertySet.HasPropertyAt(mChunk, mBit));
+      if (mBit != kBitsInChunk) {
+        return *this;
+      }
+
+      do {
+        mChunk++;
+      } while (mChunk < kChunkCount &&
+               !mPropertySet.HasPropertyInChunk(mChunk));
+      mBit = 0;
+      if (mChunk != kChunkCount) {
+        while (mBit < kBitsInChunk &&
+               !mPropertySet.HasPropertyAt(mChunk, mBit)) {
+          mBit++;
+        }
+      }
+
+      return *this;
+    }
+
+    nsCSSPropertyID operator*() {
+      MOZ_ASSERT(mChunk < kChunkCount, "Should not dereference beyond end");
+      return nsCSSPropertyIDSet::CSSPropertyAt(mChunk, mBit);
+    }
+
+   private:
+    explicit Iterator(const nsCSSPropertyIDSet& aPropertySet)
+        : mPropertySet(aPropertySet) {}
+
+    Iterator() = delete;
+    Iterator(const Iterator&) = delete;
+    Iterator& operator=(const Iterator&) = delete;
+    Iterator& operator=(const Iterator&&) = delete;
+
+    const nsCSSPropertyIDSet& mPropertySet;
+    size_t mChunk = 0;
+    size_t mBit = 0;
+  };
+
+  Iterator begin() const { return Iterator::BeginIterator(*this); }
+  Iterator end() const { return Iterator::EndIterator(*this); }
+
+ private:
+  property_set_type mProperties[kChunkCount];
+};
+
+// MOZ_DBG support
+
+inline std::ostream& operator<<(std::ostream& aOut,
+                                const nsCSSPropertyIDSet& aPropertySet) {
+  AutoTArray<nsCSSPropertyID, 16> properties;
+  for (nsCSSPropertyID property : aPropertySet) {
+    properties.AppendElement(property);
+  }
+  return aOut << properties;
+}
+
+#endif /* !defined(nsCSSPropertyIDSet_h__) */