Attach FrameProperties to each frame instead of using a shared hashtable

Dispense the shared hashtable and instead attach the frame property list directly to nsIFrame.

1 files changed, 0 insertions, 442 deletions

diff --git a/layout/base/FramePropertyTable.h b/layout/base/FramePropertyTable.h
deleted file mode 100644
index e9847efbf..000000000
--- a/layout/base/FramePropertyTable.h
+++ /dev/null
@@ -1,442 +0,0 @@
-/* -*- Mode: C++; tab-width: 20; 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 FRAMEPROPERTYTABLE_H_
-#define FRAMEPROPERTYTABLE_H_
-
-#include "mozilla/MemoryReporting.h"
-#include "mozilla/TypeTraits.h"
-#include "mozilla/Unused.h"
-#include "nsTArray.h"
-#include "nsTHashtable.h"
-#include "nsHashKeys.h"
-
-class nsIFrame;
-
-namespace mozilla {
-
-struct FramePropertyDescriptorUntyped
-{
-  /**
-   * mDestructor will be called if it's non-null.
-   */
-  typedef void UntypedDestructor(void* aPropertyValue);
-  UntypedDestructor* mDestructor;
-  /**
-   * mDestructorWithFrame will be called if it's non-null and mDestructor
-   * is null. WARNING: The frame passed to mDestructorWithFrame may
-   * be a dangling frame pointer, if this is being called during
-   * presshell teardown. Do not use it except to compare against
-   * other frame pointers. No frame will have been allocated with
-   * the same address yet.
-   */
-  typedef void UntypedDestructorWithFrame(const nsIFrame* aFrame,
-                                          void* aPropertyValue);
-  UntypedDestructorWithFrame* mDestructorWithFrame;
-  /**
-   * mDestructor and mDestructorWithFrame may both be null, in which case
-   * no value destruction is a no-op.
-   */
-
-protected:
-  /**
-   * At most one destructor should be passed in. In general, you should
-   * just use the static function FramePropertyDescriptor::New* below
-   * instead of using this constructor directly.
-   */
-  constexpr FramePropertyDescriptorUntyped(
-    UntypedDestructor* aDtor, UntypedDestructorWithFrame* aDtorWithFrame)
-    : mDestructor(aDtor)
-    , mDestructorWithFrame(aDtorWithFrame)
-  {}
-};
-
-/**
- * A pointer to a FramePropertyDescriptor serves as a unique property ID.
- * The FramePropertyDescriptor stores metadata about the property.
- * Currently the only metadata is a destructor function. The destructor
- * function is called on property values when they are overwritten or
- * deleted.
- *
- * To use this class, declare a global (i.e., file, class or function-scope
- * static member) FramePropertyDescriptor and pass its address as
- * aProperty in the FramePropertyTable methods.
- */
-template<typename T>
-struct FramePropertyDescriptor : public FramePropertyDescriptorUntyped
-{
-  typedef void Destructor(T* aPropertyValue);
-  typedef void DestructorWithFrame(const nsIFrame* aaFrame,
-                                   T* aPropertyValue);
-
-  template<Destructor Dtor>
-  static constexpr const FramePropertyDescriptor<T> NewWithDestructor()
-  {
-    return { Destruct<Dtor>, nullptr };
-  }
-
-  template<DestructorWithFrame Dtor>
-  static constexpr
-  const FramePropertyDescriptor<T> NewWithDestructorWithFrame()
-  {
-    return { nullptr, DestructWithFrame<Dtor> };
-  }
-
-  static constexpr const FramePropertyDescriptor<T> NewWithoutDestructor()
-  {
-    return { nullptr, nullptr };
-  }
-
-private:
-  constexpr FramePropertyDescriptor(
-    UntypedDestructor* aDtor, UntypedDestructorWithFrame* aDtorWithFrame)
-    : FramePropertyDescriptorUntyped(aDtor, aDtorWithFrame)
-  {}
-
-  template<Destructor Dtor>
-  static void Destruct(void* aPropertyValue)
-  {
-    Dtor(static_cast<T*>(aPropertyValue));
-  }
-
-  template<DestructorWithFrame Dtor>
-  static void DestructWithFrame(const nsIFrame* aFrame, void* aPropertyValue)
-  {
-    Dtor(aFrame, static_cast<T*>(aPropertyValue));
-  }
-};
-
-// SmallValueHolder<T> is a placeholder intended to be used as template
-// argument of FramePropertyDescriptor for types which can fit into the
-// size of a pointer directly. This class should never be defined, so
-// that we won't use it for unexpected purpose by mistake.
-template<typename T>
-class SmallValueHolder;
-
-namespace detail {
-
-template<typename T>
-struct FramePropertyTypeHelper
-{
-  typedef T* Type;
-};
-template<typename T>
-struct FramePropertyTypeHelper<SmallValueHolder<T>>
-{
-  typedef T Type;
-};
-
-}
-
-/**
- * The FramePropertyTable is optimized for storing 0 or 1 properties on
- * a given frame. Storing very large numbers of properties on a single
- * frame will not be efficient.
- * 
- * Property values are passed as void* but do not actually have to be
- * valid pointers. You can use NS_INT32_TO_PTR/NS_PTR_TO_INT32 to
- * store int32_t values. Null/zero values can be stored and retrieved.
- * Of course, the destructor function (if any) must handle such values
- * correctly.
- */
-class FramePropertyTable {
-public:
-  template<typename T>
-  using Descriptor = const FramePropertyDescriptor<T>*;
-  using UntypedDescriptor = const FramePropertyDescriptorUntyped*;
-
-  template<typename T>
-  using PropertyType = typename detail::FramePropertyTypeHelper<T>::Type;
-
-  FramePropertyTable() : mLastFrame(nullptr), mLastEntry(nullptr)
-  {
-  }
-  ~FramePropertyTable()
-  {
-    DeleteAll();
-  }
-
-  /**
-   * Set a property value on a frame. This requires one hashtable
-   * lookup (using the frame as the key) and a linear search through
-   * the properties of that frame. Any existing value for the property
-   * is destroyed.
-   */
-  template<typename T>
-  void Set(const nsIFrame* aFrame, Descriptor<T> aProperty,
-           PropertyType<T> aValue)
-  {
-    void* ptr = ReinterpretHelper<T>::ToPointer(aValue);
-    SetInternal(aFrame, aProperty, ptr);
-  }
-
-  /**
-   * @return true if @aProperty is set for @aFrame. This requires one hashtable
-   * lookup (using the frame as the key) and a linear search through the
-   * properties of that frame.
-   *
-   * In most cases, this shouldn't be used outside of assertions, because if
-   * you're doing a lookup anyway it would be far more efficient to call Get()
-   * or Remove() and check the aFoundResult outparam to find out whether the
-   * property is set. Legitimate non-assertion uses include:
-   *
-   *   - Checking if a frame property is set in cases where that's all we want
-   *     to know (i.e., we don't intend to read the actual value or remove the
-   *     property).
-   *
-   *   - Calling Has() before Set() in cases where we don't want to overwrite
-   *     an existing value for the frame property.
-   */
-  template<typename T>
-  bool Has(const nsIFrame* aFrame, Descriptor<T> aProperty)
-  {
-    bool foundResult = false;
-    mozilla::Unused << GetInternal(aFrame, aProperty, &foundResult);
-    return foundResult;
-  }
-
-  /**
-   * Get a property value for a frame. This requires one hashtable
-   * lookup (using the frame as the key) and a linear search through
-   * the properties of that frame. If the frame has no such property,
-   * returns zero-filled result, which means null for pointers and
-   * zero for integers and floating point types.
-   * @param aFoundResult if non-null, receives a value 'true' iff
-   * the frame has a value for the property. This lets callers
-   * disambiguate a null result, which can mean 'no such property' or
-   * 'property value is null'.
-   */
-  template<typename T>
-  PropertyType<T> Get(const nsIFrame* aFrame, Descriptor<T> aProperty,
-                      bool* aFoundResult = nullptr)
-  {
-    void* ptr = GetInternal(aFrame, aProperty, aFoundResult);
-    return ReinterpretHelper<T>::FromPointer(ptr);
-  }
-  /**
-   * Remove a property value for a frame. This requires one hashtable
-   * lookup (using the frame as the key) and a linear search through
-   * the properties of that frame. The old property value is returned
-   * (and not destroyed). If the frame has no such property,
-   * returns zero-filled result, which means null for pointers and
-   * zero for integers and floating point types.
-   * @param aFoundResult if non-null, receives a value 'true' iff
-   * the frame had a value for the property. This lets callers
-   * disambiguate a null result, which can mean 'no such property' or
-   * 'property value is null'.
-   */
-  template<typename T>
-  PropertyType<T> Remove(const nsIFrame* aFrame, Descriptor<T> aProperty,
-                         bool* aFoundResult = nullptr)
-  {
-    void* ptr = RemoveInternal(aFrame, aProperty, aFoundResult);
-    return ReinterpretHelper<T>::FromPointer(ptr);
-  }
-  /**
-   * Remove and destroy a property value for a frame. This requires one
-   * hashtable lookup (using the frame as the key) and a linear search
-   * through the properties of that frame. If the frame has no such
-   * property, nothing happens.
-   */
-  template<typename T>
-  void Delete(const nsIFrame* aFrame, Descriptor<T> aProperty)
-  {
-    DeleteInternal(aFrame, aProperty);
-  }
-  /**
-   * Remove and destroy all property values for a frame. This requires one
-   * hashtable lookup (using the frame as the key).
-   */
-  void DeleteAllFor(const nsIFrame* aFrame);
-  /**
-   * Remove and destroy all property values for all frames.
-   */
-  void DeleteAll();
-
-  size_t SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;
-
-protected:
-  void SetInternal(const nsIFrame* aFrame, UntypedDescriptor aProperty,
-                   void* aValue);
-
-  void* GetInternal(const nsIFrame* aFrame, UntypedDescriptor aProperty,
-                    bool* aFoundResult);
-
-  void* RemoveInternal(const nsIFrame* aFrame, UntypedDescriptor aProperty,
-                       bool* aFoundResult);
-
-  void DeleteInternal(const nsIFrame* aFrame, UntypedDescriptor aProperty);
-
-  template<typename T>
-  struct ReinterpretHelper
-  {
-    static_assert(sizeof(PropertyType<T>) <= sizeof(void*),
-                  "size of the value must never be larger than a pointer");
-
-    static void* ToPointer(PropertyType<T> aValue)
-    {
-      void* ptr = nullptr;
-      memcpy(&ptr, &aValue, sizeof(aValue));
-      return ptr;
-    }
-
-    static PropertyType<T> FromPointer(void* aPtr)
-    {
-      PropertyType<T> value;
-      memcpy(&value, &aPtr, sizeof(value));
-      return value;
-    }
-  };
-
-  template<typename T>
-  struct ReinterpretHelper<T*>
-  {
-    static void* ToPointer(T* aValue)
-    {
-      return static_cast<void*>(aValue);
-    }
-
-    static T* FromPointer(void* aPtr)
-    {
-      return static_cast<T*>(aPtr);
-    }
-  };
-
-  /**
-   * Stores a property descriptor/value pair. It can also be used to
-   * store an nsTArray of PropertyValues.
-   */
-  struct PropertyValue {
-    PropertyValue() : mProperty(nullptr), mValue(nullptr) {}
-    PropertyValue(UntypedDescriptor aProperty, void* aValue)
-      : mProperty(aProperty), mValue(aValue) {}
-
-    bool IsArray() { return !mProperty && mValue; }
-    nsTArray<PropertyValue>* ToArray()
-    {
-      NS_ASSERTION(IsArray(), "Must be array");
-      return reinterpret_cast<nsTArray<PropertyValue>*>(&mValue);
-    }
-
-    void DestroyValueFor(const nsIFrame* aFrame) {
-      if (mProperty->mDestructor) {
-        mProperty->mDestructor(mValue);
-      } else if (mProperty->mDestructorWithFrame) {
-        mProperty->mDestructorWithFrame(aFrame, mValue);
-      }
-    }
-
-    size_t SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) {
-      size_t n = 0;
-      // We don't need to measure mProperty because it always points to static
-      // memory.  As for mValue:  if it's a single value we can't measure it,
-      // because the type is opaque;  if it's an array, we measure the array
-      // storage, but we can't measure the individual values, again because
-      // their types are opaque.
-      if (IsArray()) {
-        nsTArray<PropertyValue>* array = ToArray();
-        n += array->ShallowSizeOfExcludingThis(aMallocSizeOf);
-      }
-      return n;
-    }
-
-    UntypedDescriptor mProperty;
-    void* mValue;
-  };
-
-  /**
-   * Used with an array of PropertyValues to allow lookups that compare
-   * only on the FramePropertyDescriptor.
-   */
-  class PropertyComparator {
-  public:
-    bool Equals(const PropertyValue& a, const PropertyValue& b) const {
-      return a.mProperty == b.mProperty;
-    }
-    bool Equals(UntypedDescriptor a, const PropertyValue& b) const {
-      return a == b.mProperty;
-    }
-    bool Equals(const PropertyValue& a, UntypedDescriptor b) const {
-      return a.mProperty == b;
-    }
-  };
-
-  /**
-   * Our hashtable entry. The key is an nsIFrame*, the value is a
-   * PropertyValue representing one or more property/value pairs.
-   */
-  class Entry : public nsPtrHashKey<const nsIFrame>
-  {
-  public:
-    explicit Entry(KeyTypePointer aKey) : nsPtrHashKey<const nsIFrame>(aKey) {}
-    Entry(const Entry &toCopy) :
-      nsPtrHashKey<const nsIFrame>(toCopy), mProp(toCopy.mProp) {}
-
-    size_t SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) {
-      return mProp.SizeOfExcludingThis(aMallocSizeOf);
-    }
-
-    PropertyValue mProp;
-  };
-
-  static void DeleteAllForEntry(Entry* aEntry);
-
-  // Note that mLastEntry points into mEntries, so we need to be careful about
-  // not triggering a resize of mEntries, e.g. use RawRemoveEntry() instead of
-  // RemoveEntry() in some places.
-  nsTHashtable<Entry> mEntries;
-  const nsIFrame* mLastFrame;
-  Entry* mLastEntry;
-};
-
-/**
- * This class encapsulates the properties of a frame.
- */
-class FrameProperties {
-public:
-  template<typename T> using Descriptor = FramePropertyTable::Descriptor<T>;
-  template<typename T> using PropertyType = FramePropertyTable::PropertyType<T>;
-
-  FrameProperties(FramePropertyTable* aTable, const nsIFrame* aFrame)
-    : mTable(aTable), mFrame(aFrame) {}
-
-  template<typename T>
-  void Set(Descriptor<T> aProperty, PropertyType<T> aValue) const
-  {
-    mTable->Set(mFrame, aProperty, aValue);
-  }
-
-  template<typename T>
-  bool Has(Descriptor<T> aProperty) const
-  {
-    return mTable->Has(mFrame, aProperty);
-  }
-
-  template<typename T>
-  PropertyType<T> Get(Descriptor<T> aProperty,
-                      bool* aFoundResult = nullptr) const
-  {
-    return mTable->Get(mFrame, aProperty, aFoundResult);
-  }
-  template<typename T>
-  PropertyType<T> Remove(Descriptor<T> aProperty,
-                         bool* aFoundResult = nullptr) const
-  {
-    return mTable->Remove(mFrame, aProperty, aFoundResult);
-  }
-  template<typename T>
-  void Delete(Descriptor<T> aProperty)
-  {
-    mTable->Delete(mFrame, aProperty);
-  }
-
-private:
-  FramePropertyTable* mTable;
-  const nsIFrame* mFrame;
-};
-
-} // namespace mozilla
-
-#endif /* FRAMEPROPERTYTABLE_H_ */