xpcom/ds/nsCOMArray.h
author Kris Maglione <maglione.k@gmail.com>
Thu, 10 May 2018 10:36:53 -0700
changeset 473641 1becc594554c1a273535ed175895e801667735e9
parent 392356 6e4c4e2e714794f73b06633ac42cf2a90da1d4c8
child 475080 b54db66223586b4e04f5cb926fccdacf8a176b91
permissions -rw-r--r--
Bug 1460600: Remove unsupported --enable-system-hunspell flag. r=glandium Our bundled Hunspell now significantly differs from upstream Hunspell. Most importantly, it supports loading dictionaries from jar: URIs, which is now a requirement for loading bundled and extension dictionaries. This means that system Hunspell libraries are no longer compatible with our spell checker code. We should remove the option to use them so that users don't fall into the trap of trying to use them. MozReview-Commit-ID: 2ihJe6YOnGf

/* -*- 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/. */

#ifndef nsCOMArray_h__
#define nsCOMArray_h__

#include "mozilla/Attributes.h"
#include "mozilla/ArrayIterator.h"
#include "mozilla/MemoryReporting.h"
#include "mozilla/ReverseIterator.h"

#include "nsCycleCollectionNoteChild.h"
#include "nsTArray.h"
#include "nsISupports.h"

// See below for the definition of nsCOMArray<T>

// a class that's nsISupports-specific, so that we can contain the
// work of this class in the XPCOM dll
class nsCOMArray_base
{
  friend class nsArrayBase;
protected:
  nsCOMArray_base() {}
  explicit nsCOMArray_base(int32_t aCount) : mArray(aCount) {}
  nsCOMArray_base(const nsCOMArray_base& aOther);
  ~nsCOMArray_base();

  int32_t IndexOf(nsISupports* aObject, uint32_t aStartIndex = 0) const;
  bool Contains(nsISupports* aObject) const
  {
    return IndexOf(aObject) != -1;
  }

  int32_t IndexOfObject(nsISupports* aObject) const;
  bool ContainsObject(nsISupports* aObject) const
  {
    return IndexOfObject(aObject) != -1;
  }

  typedef bool (*nsBaseArrayEnumFunc)(void* aElement, void* aData);

  // enumerate through the array with a callback.
  bool EnumerateForwards(nsBaseArrayEnumFunc aFunc, void* aData) const;

  bool EnumerateBackwards(nsBaseArrayEnumFunc aFunc, void* aData) const;

  typedef int (*nsBaseArrayComparatorFunc)(nsISupports* aElement1,
                                           nsISupports* aElement2,
                                           void* aData);

  struct nsCOMArrayComparatorContext
  {
    nsBaseArrayComparatorFunc mComparatorFunc;
    void* mData;
  };

  static int nsCOMArrayComparator(const void* aElement1, const void* aElement2,
                                  void* aData);
  void Sort(nsBaseArrayComparatorFunc aFunc, void* aData);

  bool InsertObjectAt(nsISupports* aObject, int32_t aIndex);
  void InsertElementAt(uint32_t aIndex, nsISupports* aElement);
  void InsertElementAt(uint32_t aIndex, already_AddRefed<nsISupports> aElement);
  bool InsertObjectsAt(const nsCOMArray_base& aObjects, int32_t aIndex);
  void InsertElementsAt(uint32_t aIndex, const nsCOMArray_base& aElements);
  void InsertElementsAt(uint32_t aIndex, nsISupports* const* aElements,
                        uint32_t aCount);
  void ReplaceObjectAt(nsISupports* aObject, int32_t aIndex);
  void ReplaceElementAt(uint32_t aIndex, nsISupports* aElement)
  {
    nsISupports* oldElement = mArray[aIndex];
    NS_IF_ADDREF(mArray[aIndex] = aElement);
    NS_IF_RELEASE(oldElement);
  }
  bool AppendObject(nsISupports* aObject)
  {
    return InsertObjectAt(aObject, Count());
  }
  void AppendElement(nsISupports* aElement)
  {
    InsertElementAt(Length(), aElement);
  }
  void AppendElement(already_AddRefed<nsISupports> aElement)
  {
    InsertElementAt(Length(), mozilla::Move(aElement));
  }

  bool AppendObjects(const nsCOMArray_base& aObjects)
  {
    return InsertObjectsAt(aObjects, Count());
  }
  void AppendElements(const nsCOMArray_base& aElements)
  {
    return InsertElementsAt(Length(), aElements);
  }
  void AppendElements(nsISupports* const* aElements, uint32_t aCount)
  {
    return InsertElementsAt(Length(), aElements, aCount);
  }
  bool RemoveObject(nsISupports* aObject);
  nsISupports** Elements() { return mArray.Elements(); }
  void SwapElements(nsCOMArray_base& aOther)
  {
    mArray.SwapElements(aOther.mArray);
  }

  void Adopt(nsISupports** aElements, uint32_t aCount);
  uint32_t Forget(nsISupports*** aElements);
public:
  // elements in the array (including null elements!)
  int32_t Count() const { return mArray.Length(); }
  // nsTArray-compatible version
  uint32_t Length() const { return mArray.Length(); }
  bool IsEmpty() const { return mArray.IsEmpty(); }

  // If the array grows, the newly created entries will all be null;
  // if the array shrinks, the excess entries will all be released.
  bool SetCount(int32_t aNewCount);
  // nsTArray-compatible version
  void TruncateLength(uint32_t aNewLength)
  {
    if (mArray.Length() > aNewLength) {
      RemoveElementsAt(aNewLength, mArray.Length() - aNewLength);
    }
  }

  // remove all elements in the array, and call NS_RELEASE on each one
  void Clear();

  nsISupports* ObjectAt(int32_t aIndex) const { return mArray[aIndex]; }
  // nsTArray-compatible version
  nsISupports* ElementAt(uint32_t aIndex) const { return mArray[aIndex]; }

  nsISupports* SafeObjectAt(int32_t aIndex) const
  {
    return mArray.SafeElementAt(aIndex, nullptr);
  }
  // nsTArray-compatible version
  nsISupports* SafeElementAt(uint32_t aIndex) const
  {
    return mArray.SafeElementAt(aIndex, nullptr);
  }

  nsISupports* operator[](int32_t aIndex) const { return mArray[aIndex]; }

  // remove an element at a specific position, shrinking the array
  // as necessary
  bool RemoveObjectAt(int32_t aIndex);
  // nsTArray-compatible version
  void RemoveElementAt(uint32_t aIndex);

  // remove a range of elements at a specific position, shrinking the array
  // as necessary
  bool RemoveObjectsAt(int32_t aIndex, int32_t aCount);
  // nsTArray-compatible version
  void RemoveElementsAt(uint32_t aIndex, uint32_t aCount);

  void SwapElementsAt(uint32_t aIndex1, uint32_t aIndex2)
  {
    nsISupports* tmp = mArray[aIndex1];
    mArray[aIndex1] = mArray[aIndex2];
    mArray[aIndex2] = tmp;
  }

  // Ensures there is enough space to store a total of aCapacity objects.
  // This method never deletes any objects.
  void SetCapacity(uint32_t aCapacity) { mArray.SetCapacity(aCapacity); }
  uint32_t Capacity() { return mArray.Capacity(); }

  // Measures the size of the array's element storage. If you want to measure
  // anything hanging off the array, you must iterate over the elements and
  // measure them individually; hence the "Shallow" prefix. Note that because
  // each element in an nsCOMArray<T> is actually a T* any such iteration
  // should use a SizeOfIncludingThis() function on each element rather than a
  // SizeOfExcludingThis() function, so that the memory taken by the T itself
  // is included as well as anything it points to.
  size_t ShallowSizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const
  {
    return mArray.ShallowSizeOfExcludingThis(aMallocSizeOf);
  }

private:

  // the actual storage
  nsTArray<nsISupports*> mArray;

  // don't implement these, defaults will muck with refcounts!
  nsCOMArray_base& operator=(const nsCOMArray_base& aOther) = delete;
};

inline void
ImplCycleCollectionUnlink(nsCOMArray_base& aField)
{
  aField.Clear();
}

inline void
ImplCycleCollectionTraverse(nsCycleCollectionTraversalCallback& aCallback,
                            nsCOMArray_base& aField,
                            const char* aName,
                            uint32_t aFlags = 0)
{
  aFlags |= CycleCollectionEdgeNameArrayFlag;
  int32_t length = aField.Count();
  for (int32_t i = 0; i < length; ++i) {
    CycleCollectionNoteChild(aCallback, aField[i], aName, aFlags);
  }
}


// a non-XPCOM, refcounting array of XPCOM objects
// used as a member variable or stack variable - this object is NOT
// refcounted, but the objects that it holds are
//
// most of the read-only accessors like ObjectAt()/etc do NOT refcount
// on the way out. This means that you can do one of two things:
//
// * does an addref, but holds onto a reference
// nsCOMPtr<T> foo = array[i];
//
// * avoids the refcount, but foo might go stale if array[i] is ever
// * modified/removed. Be careful not to NS_RELEASE(foo)!
// T* foo = array[i];
//
// This array will accept null as an argument for any object, and will store
// null in the array. But that also means that methods like ObjectAt() may
// return null when referring to an existing, but null entry in the array.
template<class T>
class nsCOMArray : public nsCOMArray_base
{
public:
  typedef int32_t                                       index_type;
  typedef mozilla::ArrayIterator<T*, nsCOMArray>        iterator;
  typedef mozilla::ArrayIterator<const T*, nsCOMArray>  const_iterator;
  typedef mozilla::ReverseIterator<iterator>            reverse_iterator;
  typedef mozilla::ReverseIterator<const_iterator>      const_reverse_iterator;

  nsCOMArray() {}
  explicit nsCOMArray(int32_t aCount) : nsCOMArray_base(aCount) {}
  explicit nsCOMArray(const nsCOMArray<T>& aOther) : nsCOMArray_base(aOther) {}
  nsCOMArray(nsCOMArray<T>&& aOther) { SwapElements(aOther); }
  ~nsCOMArray() {}

  // We have a move assignment operator, but no copy assignment operator.
  nsCOMArray<T>& operator=(nsCOMArray<T> && aOther)
  {
    SwapElements(aOther);
    return *this;
  }

  // these do NOT refcount on the way out, for speed
  T* ObjectAt(int32_t aIndex) const
  {
    return static_cast<T*>(nsCOMArray_base::ObjectAt(aIndex));
  }
  // nsTArray-compatible version
  T* ElementAt(uint32_t aIndex) const
  {
    return static_cast<T*>(nsCOMArray_base::ElementAt(aIndex));
  }

  // these do NOT refcount on the way out, for speed
  T* SafeObjectAt(int32_t aIndex) const
  {
    return static_cast<T*>(nsCOMArray_base::SafeObjectAt(aIndex));
  }
  // nsTArray-compatible version
  T* SafeElementAt(uint32_t aIndex) const
  {
    return static_cast<T*>(nsCOMArray_base::SafeElementAt(aIndex));
  }

  // indexing operator for syntactic sugar
  T* operator[](int32_t aIndex) const { return ObjectAt(aIndex); }

  // index of the element in question.. does NOT refcount
  // note: this does not check COM object identity. Use
  // IndexOfObject() for that purpose
  int32_t IndexOf(T* aObject, uint32_t aStartIndex = 0) const
  {
    return nsCOMArray_base::IndexOf(aObject, aStartIndex);
  }
  bool Contains(T* aObject) const
  {
    return nsCOMArray_base::Contains(aObject);
  }

  // index of the element in question.. be careful!
  // this is much slower than IndexOf() because it uses
  // QueryInterface to determine actual COM identity of the object
  // if you need to do this frequently then consider enforcing
  // COM object identity before adding/comparing elements
  int32_t IndexOfObject(T* aObject) const
  {
    return nsCOMArray_base::IndexOfObject(aObject);
  }
  bool ContainsObject(nsISupports* aObject) const
  {
    return nsCOMArray_base::ContainsObject(aObject);
  }

  // inserts aObject at aIndex, shifting the objects at aIndex and
  // later to make space
  bool InsertObjectAt(T* aObject, int32_t aIndex)
  {
    return nsCOMArray_base::InsertObjectAt(aObject, aIndex);
  }
  // nsTArray-compatible version
  void InsertElementAt(uint32_t aIndex, T* aElement)
  {
    nsCOMArray_base::InsertElementAt(aIndex, aElement);
  }

  // inserts the objects from aObject at aIndex, shifting the
  // objects at aIndex and later to make space
  bool InsertObjectsAt(const nsCOMArray<T>& aObjects, int32_t aIndex)
  {
    return nsCOMArray_base::InsertObjectsAt(aObjects, aIndex);
  }
  // nsTArray-compatible version
  void InsertElementsAt(uint32_t aIndex, const nsCOMArray<T>& aElements)
  {
    nsCOMArray_base::InsertElementsAt(aIndex, aElements);
  }
  void InsertElementsAt(uint32_t aIndex, T* const* aElements, uint32_t aCount)
  {
    nsCOMArray_base::InsertElementsAt(
      aIndex, reinterpret_cast<nsISupports* const*>(aElements), aCount);
  }

  // replaces an existing element. Warning: if the array grows,
  // the newly created entries will all be null
  void ReplaceObjectAt(T* aObject, int32_t aIndex)
  {
    nsCOMArray_base::ReplaceObjectAt(aObject, aIndex);
  }
  // nsTArray-compatible version
  void ReplaceElementAt(uint32_t aIndex, T* aElement)
  {
    nsCOMArray_base::ReplaceElementAt(aIndex, aElement);
  }

  typedef int (*nsCOMArrayComparatorFunc)(T* aElement1, T* aElement2,
                                          void* aData);

  void Sort(nsCOMArrayComparatorFunc aFunc, void* aData)
  {
    nsCOMArray_base::Sort(nsBaseArrayComparatorFunc(aFunc), aData);
  }

  // append an object, growing the array as necessary
  bool AppendObject(T* aObject)
  {
    return nsCOMArray_base::AppendObject(aObject);
  }
  // nsTArray-compatible version
  void AppendElement(T* aElement)
  {
    nsCOMArray_base::AppendElement(aElement);
  }
  void AppendElement(already_AddRefed<T> aElement)
  {
    nsCOMArray_base::AppendElement(mozilla::Move(aElement));
  }

  // append objects, growing the array as necessary
  bool AppendObjects(const nsCOMArray<T>& aObjects)
  {
    return nsCOMArray_base::AppendObjects(aObjects);
  }
  // nsTArray-compatible version
  void AppendElements(const nsCOMArray<T>& aElements)
  {
    return nsCOMArray_base::AppendElements(aElements);
  }
  void AppendElements(T* const* aElements, uint32_t aCount)
  {
    InsertElementsAt(Length(), aElements, aCount);
  }

  // remove the first instance of the given object and shrink the
  // array as necessary
  // Warning: if you pass null here, it will remove the first null element
  bool RemoveObject(T* aObject)
  {
    return nsCOMArray_base::RemoveObject(aObject);
  }
  // nsTArray-compatible version
  bool RemoveElement(T* aElement)
  {
    return nsCOMArray_base::RemoveObject(aElement);
  }

  T** Elements()
  {
    return reinterpret_cast<T**>(nsCOMArray_base::Elements());
  }
  void SwapElements(nsCOMArray<T>& aOther)
  {
    nsCOMArray_base::SwapElements(aOther);
  }

  /**
   * Adopt parameters that resulted from an XPIDL outparam. The aElements
   * parameter will be freed as a result of the call.
   *
   * Example usage:
   * nsCOMArray<nsISomeInterface> array;
   * nsISomeInterface** elements;
   * uint32_t length;
   * ptr->GetSomeArray(&elements, &length);
   * array.Adopt(elements, length);
   */
  void Adopt(T** aElements, uint32_t aSize)
  {
    nsCOMArray_base::Adopt(reinterpret_cast<nsISupports**>(aElements), aSize);
  }

  /**
   * Export the contents of this array to an XPIDL outparam. The array will be
   * Clear()'d after this operation.
   *
   * Example usage:
   * nsCOMArray<nsISomeInterface> array;
   * *length = array.Forget(retval);
   */
  uint32_t Forget(T*** aElements)
  {
    return nsCOMArray_base::Forget(reinterpret_cast<nsISupports***>(aElements));
  }

  // Methods for range-based for loops.
  iterator begin() { return iterator(*this, 0); }
  const_iterator begin() const { return const_iterator(*this, 0); }
  const_iterator cbegin() const { return begin(); }
  iterator end() { return iterator(*this, Length()); }
  const_iterator end() const { return const_iterator(*this, Length()); }
  const_iterator cend() const { return end(); }

  // Methods for reverse iterating.
  reverse_iterator rbegin() { return reverse_iterator(end()); }
  const_reverse_iterator rbegin() const { return const_reverse_iterator(end()); }
  const_reverse_iterator crbegin() const { return rbegin(); }
  reverse_iterator rend() { return reverse_iterator(begin()); }
  const_reverse_iterator rend() const { return const_reverse_iterator(begin()); }
  const_reverse_iterator crend() const { return rend(); }

private:

  // don't implement these!
  nsCOMArray<T>& operator=(const nsCOMArray<T>& aOther) = delete;
};

template<typename T>
inline void
ImplCycleCollectionUnlink(nsCOMArray<T>& aField)
{
  aField.Clear();
}

template<typename E>
inline void
ImplCycleCollectionTraverse(nsCycleCollectionTraversalCallback& aCallback,
                            nsCOMArray<E>& aField,
                            const char* aName,
                            uint32_t aFlags = 0)
{
  aFlags |= CycleCollectionEdgeNameArrayFlag;
  int32_t length = aField.Count();
  for (int32_t i = 0; i < length; ++i) {
    CycleCollectionNoteChild(aCallback, aField[i], aName, aFlags);
  }
}

#endif