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gecko-dev/xpcom/glue/nsTArray.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/. */
#ifndef nsTArray_h__
#define nsTArray_h__
#include "nsTArrayForwardDeclare.h"
#include "mozilla/Alignment.h"
#include "mozilla/Assertions.h"
#include "mozilla/Attributes.h"
#include "mozilla/BinarySearch.h"
#include "mozilla/fallible.h"
#include "mozilla/MathAlgorithms.h"
#include "mozilla/MemoryReporting.h"
#include "mozilla/Move.h"
#include "mozilla/ReverseIterator.h"
#include "mozilla/TypeTraits.h"
#include <string.h>
#include "nsCycleCollectionNoteChild.h"
#include "nsAlgorithm.h"
#include "nscore.h"
#include "nsQuickSort.h"
#include "nsDebug.h"
#include "nsISupportsImpl.h"
#include <new>
namespace JS {
template<class T>
class Heap;
} /* namespace JS */
class nsRegion;
class nsIntRegion;
namespace mozilla {
namespace layers {
struct TileClient;
} // namespace layers
} // namespace mozilla
//
// nsTArray is a resizable array class, like std::vector.
//
// Unlike std::vector, which follows C++'s construction/destruction rules,
// nsTArray assumes that your "T" can be memmoved()'ed safely.
//
// The public classes defined in this header are
//
// nsTArray<T>,
// FallibleTArray<T>,
// nsAutoTArray<T, N>, and
// AutoFallibleTArray<T, N>.
//
// nsTArray and nsAutoTArray are infallible; if one tries to make an allocation
// which fails, it crashes the program. In contrast, FallibleTArray and
// AutoFallibleTArray are fallible; if you use one of these classes, you must
// check the return values of methods such as Append() which may allocate. If
// in doubt, choose an infallible type.
//
// InfallibleTArray and AutoInfallibleTArray are aliases for nsTArray and
// nsAutoTArray.
//
// If you just want to declare the nsTArray types (e.g., if you're in a header
// file and don't need the full nsTArray definitions) consider including
// nsTArrayForwardDeclare.h instead of nsTArray.h.
//
// The template parameter (i.e., T in nsTArray<T>) specifies the type of the
// elements and has the following requirements:
//
// T MUST be safely memmove()'able.
// T MUST define a copy-constructor.
// T MAY define operator< for sorting.
// T MAY define operator== for searching.
//
// (Note that the memmove requirement may be relaxed for certain types - see
// nsTArray_CopyChooser below.)
//
// For methods taking a Comparator instance, the Comparator must be a class
// defining the following methods:
//
// class Comparator {
// public:
// /** @return True if the elements are equals; false otherwise. */
// bool Equals(const elem_type& a, const Item& b) const;
//
// /** @return True if (a < b); false otherwise. */
// bool LessThan(const elem_type& a, const Item& b) const;
// };
//
// The Equals method is used for searching, and the LessThan method is used for
// searching and sorting. The |Item| type above can be arbitrary, but must
// match the Item type passed to the sort or search function.
//
//
// nsTArrayFallibleResult and nsTArrayInfallibleResult types are proxy types
// which are used because you cannot use a templated type which is bound to
// void as an argument to a void function. In order to work around that, we
// encode either a void or a boolean inside these proxy objects, and pass them
// to the aforementioned function instead, and then use the type information to
// decide what to do in the function.
//
// Note that public nsTArray methods should never return a proxy type. Such
// types are only meant to be used in the internal nsTArray helper methods.
// Public methods returning non-proxy types cannot be called from other
// nsTArray members.
//
struct nsTArrayFallibleResult
{
// Note: allows implicit conversions from and to bool
MOZ_IMPLICIT nsTArrayFallibleResult(bool aResult) : mResult(aResult) {}
MOZ_IMPLICIT operator bool() { return mResult; }
private:
bool mResult;
};
struct nsTArrayInfallibleResult
{
};
//
// nsTArray*Allocators must all use the same |free()|, to allow swap()'ing
// between fallible and infallible variants.
//
struct nsTArrayFallibleAllocatorBase
{
typedef bool ResultType;
typedef nsTArrayFallibleResult ResultTypeProxy;
static ResultType Result(ResultTypeProxy aResult) { return aResult; }
static bool Successful(ResultTypeProxy aResult) { return aResult; }
static ResultTypeProxy SuccessResult() { return true; }
static ResultTypeProxy FailureResult() { return false; }
static ResultType ConvertBoolToResultType(bool aValue) { return aValue; }
};
struct nsTArrayInfallibleAllocatorBase
{
typedef void ResultType;
typedef nsTArrayInfallibleResult ResultTypeProxy;
static ResultType Result(ResultTypeProxy aResult) {}
static bool Successful(ResultTypeProxy) { return true; }
static ResultTypeProxy SuccessResult() { return ResultTypeProxy(); }
static ResultTypeProxy FailureResult()
{
NS_RUNTIMEABORT("Infallible nsTArray should never fail");
return ResultTypeProxy();
}
static ResultType ConvertBoolToResultType(bool aValue)
{
if (!aValue) {
NS_RUNTIMEABORT("infallible nsTArray should never convert false to ResultType");
}
}
};
#if defined(MOZALLOC_HAVE_XMALLOC)
#include "mozilla/mozalloc_abort.h"
struct nsTArrayFallibleAllocator : nsTArrayFallibleAllocatorBase
{
static void* Malloc(size_t aSize) { return malloc(aSize); }
static void* Realloc(void* aPtr, size_t aSize)
{
return realloc(aPtr, aSize);
}
static void Free(void* aPtr) { free(aPtr); }
static void SizeTooBig(size_t) {}
};
struct nsTArrayInfallibleAllocator : nsTArrayInfallibleAllocatorBase
{
static void* Malloc(size_t aSize) { return moz_xmalloc(aSize); }
static void* Realloc(void* aPtr, size_t aSize)
{
return moz_xrealloc(aPtr, aSize);
}
static void Free(void* aPtr) { free(aPtr); }
static void SizeTooBig(size_t aSize) { NS_ABORT_OOM(aSize); }
};
#else
#include <stdlib.h>
struct nsTArrayFallibleAllocator : nsTArrayFallibleAllocatorBase
{
static void* Malloc(size_t aSize) { return malloc(aSize); }
static void* Realloc(void* aPtr, size_t aSize) { return realloc(aPtr, aSize); }
static void Free(void* aPtr) { free(aPtr); }
static void SizeTooBig(size_t) {}
};
struct nsTArrayInfallibleAllocator : nsTArrayInfallibleAllocatorBase
{
static void* Malloc(size_t aSize)
{
void* ptr = malloc(aSize);
if (MOZ_UNLIKELY(!ptr)) {
NS_ABORT_OOM(aSize);
}
return ptr;
}
static void* Realloc(void* aPtr, size_t aSize)
{
void* newptr = realloc(aPtr, aSize);
if (MOZ_UNLIKELY(!newptr && aSize)) {
NS_ABORT_OOM(aSize);
}
return newptr;
}
static void Free(void* aPtr) { free(aPtr); }
static void SizeTooBig(size_t aSize) { NS_ABORT_OOM(aSize); }
};
#endif
// nsTArray_base stores elements into the space allocated beyond
// sizeof(*this). This is done to minimize the size of the nsTArray
// object when it is empty.
struct nsTArrayHeader
{
static nsTArrayHeader sEmptyHdr;
uint32_t mLength;
uint32_t mCapacity : 31;
uint32_t mIsAutoArray : 1;
};
// This class provides a SafeElementAt method to nsTArray<T*> which does
// not take a second default value parameter.
template<class E, class Derived>
struct nsTArray_SafeElementAtHelper
{
typedef E* elem_type;
typedef size_t index_type;
// No implementation is provided for these two methods, and that is on
// purpose, since we don't support these functions on non-pointer type
// instantiations.
elem_type& SafeElementAt(index_type aIndex);
const elem_type& SafeElementAt(index_type aIndex) const;
};
template<class E, class Derived>
struct nsTArray_SafeElementAtHelper<E*, Derived>
{
typedef E* elem_type;
typedef size_t index_type;
elem_type SafeElementAt(index_type aIndex)
{
return static_cast<Derived*>(this)->SafeElementAt(aIndex, nullptr);
}
const elem_type SafeElementAt(index_type aIndex) const
{
return static_cast<const Derived*>(this)->SafeElementAt(aIndex, nullptr);
}
};
// E is the base type that the smart pointer is templated over; the
// smart pointer can act as E*.
template<class E, class Derived>
struct nsTArray_SafeElementAtSmartPtrHelper
{
typedef E* elem_type;
typedef size_t index_type;
elem_type SafeElementAt(index_type aIndex)
{
return static_cast<Derived*>(this)->SafeElementAt(aIndex, nullptr);
}
const elem_type SafeElementAt(index_type aIndex) const
{
return static_cast<const Derived*>(this)->SafeElementAt(aIndex, nullptr);
}
};
template<class T> class nsCOMPtr;
template<class E, class Derived>
struct nsTArray_SafeElementAtHelper<nsCOMPtr<E>, Derived>
: public nsTArray_SafeElementAtSmartPtrHelper<E, Derived>
{
};
template<class T> class nsRefPtr;
template<class E, class Derived>
struct nsTArray_SafeElementAtHelper<nsRefPtr<E>, Derived>
: public nsTArray_SafeElementAtSmartPtrHelper<E, Derived>
{
};
namespace mozilla {
template<class T> class OwningNonNull;
} // namespace mozilla
template<class E, class Derived>
struct nsTArray_SafeElementAtHelper<mozilla::OwningNonNull<E>, Derived>
{
typedef E* elem_type;
typedef size_t index_type;
elem_type SafeElementAt(index_type aIndex)
{
if (aIndex < static_cast<Derived*>(this)->Length()) {
return static_cast<Derived*>(this)->ElementAt(aIndex);
}
return nullptr;
}
const elem_type SafeElementAt(index_type aIndex) const
{
if (aIndex < static_cast<const Derived*>(this)->Length()) {
return static_cast<const Derived*>(this)->ElementAt(aIndex);
}
return nullptr;
}
};
//
// This class serves as a base class for nsTArray. It shouldn't be used
// directly. It holds common implementation code that does not depend on the
// element type of the nsTArray.
//
template<class Alloc, class Copy>
class nsTArray_base
{
// Allow swapping elements with |nsTArray_base|s created using a
// different allocator. This is kosher because all allocators use
// the same free().
template<class Allocator, class Copier>
friend class nsTArray_base;
protected:
typedef nsTArrayHeader Header;
public:
typedef size_t size_type;
typedef size_t index_type;
// @return The number of elements in the array.
size_type Length() const { return mHdr->mLength; }
// @return True if the array is empty or false otherwise.
bool IsEmpty() const { return Length() == 0; }
// @return The number of elements that can fit in the array without forcing
// the array to be re-allocated. The length of an array is always less
// than or equal to its capacity.
size_type Capacity() const { return mHdr->mCapacity; }
#ifdef DEBUG
void* DebugGetHeader() const { return mHdr; }
#endif
protected:
nsTArray_base();
~nsTArray_base();
// Resize the storage if necessary to achieve the requested capacity.
// @param aCapacity The requested number of array elements.
// @param aElemSize The size of an array element.
// @return False if insufficient memory is available; true otherwise.
template<typename ActualAlloc>
typename ActualAlloc::ResultTypeProxy EnsureCapacity(size_type aCapacity,
size_type aElemSize);
// Resize the storage to the minimum required amount.
// @param aElemSize The size of an array element.
// @param aElemAlign The alignment in bytes of an array element.
template<typename ActualAlloc>
void ShrinkCapacity(size_type aElemSize, size_t aElemAlign);
// This method may be called to resize a "gap" in the array by shifting
// elements around. It updates mLength appropriately. If the resulting
// array has zero elements, then the array's memory is free'd.
// @param aStart The starting index of the gap.
// @param aOldLen The current length of the gap.
// @param aNewLen The desired length of the gap.
// @param aElemSize The size of an array element.
// @param aElemAlign The alignment in bytes of an array element.
template<typename ActualAlloc>
void ShiftData(index_type aStart, size_type aOldLen, size_type aNewLen,
size_type aElemSize, size_t aElemAlign);
// This method increments the length member of the array's header.
// Note that mHdr may actually be sEmptyHdr in the case where a
// zero-length array is inserted into our array. But then aNum should
// always be 0.
void IncrementLength(size_t aNum)
{
if (mHdr == EmptyHdr()) {
if (MOZ_UNLIKELY(aNum != 0)) {
// Writing a non-zero length to the empty header would be extremely bad.
MOZ_CRASH();
}
} else {
mHdr->mLength += aNum;
}
}
// This method inserts blank slots into the array.
// @param aIndex the place to insert the new elements. This must be no
// greater than the current length of the array.
// @param aCount the number of slots to insert
// @param aElementSize the size of an array element.
// @param aElemAlign the alignment in bytes of an array element.
template<typename ActualAlloc>
bool InsertSlotsAt(index_type aIndex, size_type aCount,
size_type aElementSize, size_t aElemAlign);
template<typename ActualAlloc, class Allocator>
typename ActualAlloc::ResultTypeProxy
SwapArrayElements(nsTArray_base<Allocator, Copy>& aOther,
size_type aElemSize,
size_t aElemAlign);
// This is an RAII class used in SwapArrayElements.
class IsAutoArrayRestorer
{
public:
IsAutoArrayRestorer(nsTArray_base<Alloc, Copy>& aArray, size_t aElemAlign);
~IsAutoArrayRestorer();
private:
nsTArray_base<Alloc, Copy>& mArray;
size_t mElemAlign;
bool mIsAuto;
};
// Helper function for SwapArrayElements. Ensures that if the array
// is an nsAutoTArray that it doesn't use the built-in buffer.
template<typename ActualAlloc>
bool EnsureNotUsingAutoArrayBuffer(size_type aElemSize);
// Returns true if this nsTArray is an nsAutoTArray with a built-in buffer.
bool IsAutoArray() const { return mHdr->mIsAutoArray; }
// Returns a Header for the built-in buffer of this nsAutoTArray.
Header* GetAutoArrayBuffer(size_t aElemAlign)
{
MOZ_ASSERT(IsAutoArray(), "Should be an auto array to call this");
return GetAutoArrayBufferUnsafe(aElemAlign);
}
const Header* GetAutoArrayBuffer(size_t aElemAlign) const
{
MOZ_ASSERT(IsAutoArray(), "Should be an auto array to call this");
return GetAutoArrayBufferUnsafe(aElemAlign);
}
// Returns a Header for the built-in buffer of this nsAutoTArray, but doesn't
// assert that we are an nsAutoTArray.
Header* GetAutoArrayBufferUnsafe(size_t aElemAlign)
{
return const_cast<Header*>(static_cast<const nsTArray_base<Alloc, Copy>*>(
this)->GetAutoArrayBufferUnsafe(aElemAlign));
}
const Header* GetAutoArrayBufferUnsafe(size_t aElemAlign) const;
// Returns true if this is an nsAutoTArray and it currently uses the
// built-in buffer to store its elements.
bool UsesAutoArrayBuffer() const;
// The array's elements (prefixed with a Header). This pointer is never
// null. If the array is empty, then this will point to sEmptyHdr.
Header* mHdr;
Header* Hdr() const { return mHdr; }
Header** PtrToHdr() { return &mHdr; }
static Header* EmptyHdr() { return &Header::sEmptyHdr; }
};
//
// This class defines convenience functions for element specific operations.
// Specialize this template if necessary.
//
template<class E>
class nsTArrayElementTraits
{
public:
// Invoke the default constructor in place.
static inline void Construct(E* aE)
{
// Do NOT call "E()"! That triggers C++ "default initialization"
// which zeroes out POD ("plain old data") types such as regular
// ints. We don't want that because it can be a performance issue
// and people don't expect it; nsTArray should work like a regular
// C/C++ array in this respect.
new (static_cast<void*>(aE)) E;
}
// Invoke the copy-constructor in place.
template<class A>
static inline void Construct(E* aE, A&& aArg)
{
typedef typename mozilla::RemoveCV<E>::Type E_NoCV;
typedef typename mozilla::RemoveCV<A>::Type A_NoCV;
static_assert(!mozilla::IsSame<E_NoCV*, A_NoCV>::value,
"For safety, we disallow constructing nsTArray<E> elements "
"from E* pointers. See bug 960591.");
new (static_cast<void*>(aE)) E(mozilla::Forward<A>(aArg));
}
// Invoke the destructor in place.
static inline void Destruct(E* aE) { aE->~E(); }
};
// The default comparator used by nsTArray
template<class A, class B>
class nsDefaultComparator
{
public:
bool Equals(const A& aA, const B& aB) const { return aA == aB; }
bool LessThan(const A& aA, const B& aB) const { return aA < aB; }
};
template<class E> class InfallibleTArray;
template<class E> class FallibleTArray;
template<bool IsPod, bool IsSameType>
struct AssignRangeAlgorithm
{
template<class Item, class ElemType, class IndexType, class SizeType>
static void implementation(ElemType* aElements, IndexType aStart,
SizeType aCount, const Item* aValues)
{
ElemType* iter = aElements + aStart;
ElemType* end = iter + aCount;
for (; iter != end; ++iter, ++aValues) {
nsTArrayElementTraits<ElemType>::Construct(iter, *aValues);
}
}
};
template<>
struct AssignRangeAlgorithm<true, true>
{
template<class Item, class ElemType, class IndexType, class SizeType>
static void implementation(ElemType* aElements, IndexType aStart,
SizeType aCount, const Item* aValues)
{
memcpy(aElements + aStart, aValues, aCount * sizeof(ElemType));
}
};
//
// Normally elements are copied with memcpy and memmove, but for some element
// types that is problematic. The nsTArray_CopyChooser template class can be
// specialized to ensure that copying calls constructors and destructors
// instead, as is done below for JS::Heap<E> elements.
//
//
// A class that defines how to copy elements using memcpy/memmove.
//
struct nsTArray_CopyWithMemutils
{
const static bool allowRealloc = true;
static void CopyElements(void* aDest, const void* aSrc, size_t aCount,
size_t aElemSize)
{
memcpy(aDest, aSrc, aCount * aElemSize);
}
static void CopyHeaderAndElements(void* aDest, const void* aSrc,
size_t aCount, size_t aElemSize)
{
memcpy(aDest, aSrc, sizeof(nsTArrayHeader) + aCount * aElemSize);
}
static void MoveElements(void* aDest, const void* aSrc, size_t aCount,
size_t aElemSize)
{
memmove(aDest, aSrc, aCount * aElemSize);
}
};
//
// A template class that defines how to copy elements calling their constructors
// and destructors appropriately.
//
template<class ElemType>
struct nsTArray_CopyWithConstructors
{
typedef nsTArrayElementTraits<ElemType> traits;
const static bool allowRealloc = false;
static void CopyElements(void* aDest, void* aSrc, size_t aCount,
size_t aElemSize)
{
ElemType* destElem = static_cast<ElemType*>(aDest);
ElemType* srcElem = static_cast<ElemType*>(aSrc);
ElemType* destElemEnd = destElem + aCount;
#ifdef DEBUG
ElemType* srcElemEnd = srcElem + aCount;
MOZ_ASSERT(srcElemEnd <= destElem || srcElemEnd > destElemEnd);
#endif
while (destElem != destElemEnd) {
traits::Construct(destElem, *srcElem);
traits::Destruct(srcElem);
++destElem;
++srcElem;
}
}
static void CopyHeaderAndElements(void* aDest, void* aSrc, size_t aCount,
size_t aElemSize)
{
nsTArrayHeader* destHeader = static_cast<nsTArrayHeader*>(aDest);
nsTArrayHeader* srcHeader = static_cast<nsTArrayHeader*>(aSrc);
*destHeader = *srcHeader;
CopyElements(static_cast<uint8_t*>(aDest) + sizeof(nsTArrayHeader),
static_cast<uint8_t*>(aSrc) + sizeof(nsTArrayHeader),
aCount, aElemSize);
}
static void MoveElements(void* aDest, void* aSrc, size_t aCount,
size_t aElemSize)
{
ElemType* destElem = static_cast<ElemType*>(aDest);
ElemType* srcElem = static_cast<ElemType*>(aSrc);
ElemType* destElemEnd = destElem + aCount;
ElemType* srcElemEnd = srcElem + aCount;
if (destElem == srcElem) {
return; // In practice, we don't do this.
} else if (srcElemEnd > destElem && srcElemEnd < destElemEnd) {
while (destElemEnd != destElem) {
--destElemEnd;
--srcElemEnd;
traits::Construct(destElemEnd, *srcElemEnd);
traits::Destruct(srcElem);
}
} else {
CopyElements(aDest, aSrc, aCount, aElemSize);
}
}
};
//
// The default behaviour is to use memcpy/memmove for everything.
//
template<class E>
struct MOZ_NEEDS_MEMMOVABLE_TYPE nsTArray_CopyChooser
{
typedef nsTArray_CopyWithMemutils Type;
};
//
// Some classes require constructors/destructors to be called, so they are
// specialized here.
//
template<class E>
struct nsTArray_CopyChooser<JS::Heap<E>>
{
typedef nsTArray_CopyWithConstructors<JS::Heap<E>> Type;
};
template<>
struct nsTArray_CopyChooser<nsRegion>
{
typedef nsTArray_CopyWithConstructors<nsRegion> Type;
};
template<>
struct nsTArray_CopyChooser<nsIntRegion>
{
typedef nsTArray_CopyWithConstructors<nsIntRegion> Type;
};
template<>
struct nsTArray_CopyChooser<mozilla::layers::TileClient>
{
typedef nsTArray_CopyWithConstructors<mozilla::layers::TileClient> Type;
};
//
// Base class for nsTArray_Impl that is templated on element type and derived
// nsTArray_Impl class, to allow extra conversions to be added for specific
// types.
//
template<class E, class Derived>
struct nsTArray_TypedBase : public nsTArray_SafeElementAtHelper<E, Derived>
{
};
//
// Specialization of nsTArray_TypedBase for arrays containing JS::Heap<E>
// elements.
//
// These conversions are safe because JS::Heap<E> and E share the same
// representation, and since the result of the conversions are const references
// we won't miss any barriers.
//
// The static_cast is necessary to obtain the correct address for the derived
// class since we are a base class used in multiple inheritance.
//
template<class E, class Derived>
struct nsTArray_TypedBase<JS::Heap<E>, Derived>
: public nsTArray_SafeElementAtHelper<JS::Heap<E>, Derived>
{
operator const nsTArray<E>&()
{
static_assert(sizeof(E) == sizeof(JS::Heap<E>),
"JS::Heap<E> must be binary compatible with E.");
Derived* self = static_cast<Derived*>(this);
return *reinterpret_cast<nsTArray<E> *>(self);
}
operator const FallibleTArray<E>&()
{
Derived* self = static_cast<Derived*>(this);
return *reinterpret_cast<FallibleTArray<E> *>(self);
}
};
namespace detail {
template<class Item, class Comparator>
struct ItemComparatorEq
{
const Item& mItem;
const Comparator& mComp;
ItemComparatorEq(const Item& aItem, const Comparator& aComp)
: mItem(aItem)
, mComp(aComp)
{}
template<class T>
int operator()(const T& aElement) const {
if (mComp.Equals(aElement, mItem)) {
return 0;
}
return mComp.LessThan(aElement, mItem) ? 1 : -1;
}
};
template<class Item, class Comparator>
struct ItemComparatorFirstElementGT
{
const Item& mItem;
const Comparator& mComp;
ItemComparatorFirstElementGT(const Item& aItem, const Comparator& aComp)
: mItem(aItem)
, mComp(aComp)
{}
template<class T>
int operator()(const T& aElement) const {
if (mComp.LessThan(aElement, mItem) ||
mComp.Equals(aElement, mItem)) {
return 1;
} else {
return -1;
}
}
};
} // namespace detail
//
// nsTArray_Impl contains most of the guts supporting nsTArray, FallibleTArray,
// nsAutoTArray, and AutoFallibleTArray.
//
// The only situation in which you might need to use nsTArray_Impl in your code
// is if you're writing code which mutates a TArray which may or may not be
// infallible.
//
// Code which merely reads from a TArray which may or may not be infallible can
// simply cast the TArray to |const nsTArray&|; both fallible and infallible
// TArrays can be cast to |const nsTArray&|.
//
template<class E, class Alloc>
class nsTArray_Impl
: public nsTArray_base<Alloc, typename nsTArray_CopyChooser<E>::Type>
, public nsTArray_TypedBase<E, nsTArray_Impl<E, Alloc>>
{
private:
typedef nsTArrayFallibleAllocator FallibleAlloc;
public:
typedef typename nsTArray_CopyChooser<E>::Type copy_type;
typedef nsTArray_base<Alloc, copy_type> base_type;
typedef typename base_type::size_type size_type;
typedef typename base_type::index_type index_type;
typedef E elem_type;
typedef nsTArray_Impl<E, Alloc> self_type;
typedef nsTArrayElementTraits<E> elem_traits;
typedef nsTArray_SafeElementAtHelper<E, self_type> safeelementat_helper_type;
typedef elem_type* iterator;
typedef const elem_type* const_iterator;
typedef mozilla::ReverseIterator<elem_type*> reverse_iterator;
typedef mozilla::ReverseIterator<const elem_type*> const_reverse_iterator;
using safeelementat_helper_type::SafeElementAt;
using base_type::EmptyHdr;
// A special value that is used to indicate an invalid or unknown index
// into the array.
static const index_type NoIndex = index_type(-1);
using base_type::Length;
//
// Finalization method
//
~nsTArray_Impl() { Clear(); }
//
// Initialization methods
//
nsTArray_Impl() {}
// Initialize this array and pre-allocate some number of elements.
explicit nsTArray_Impl(size_type aCapacity) { SetCapacity(aCapacity); }
// Initialize this array with an r-value.
// Allow different types of allocators, since the allocator doesn't matter.
template<typename Allocator>
explicit nsTArray_Impl(nsTArray_Impl<E, Allocator>&& aOther)
{
SwapElements(aOther);
}
// The array's copy-constructor performs a 'deep' copy of the given array.
// @param aOther The array object to copy.
//
// It's very important that we declare this method as taking |const
// self_type&| as opposed to taking |const nsTArray_Impl<E, OtherAlloc>| for
// an arbitrary OtherAlloc.
//
// If we don't declare a constructor taking |const self_type&|, C++ generates
// a copy-constructor for this class which merely copies the object's
// members, which is obviously wrong.
//
// You can pass an nsTArray_Impl<E, OtherAlloc> to this method because
// nsTArray_Impl<E, X> can be cast to const nsTArray_Impl<E, Y>&. So the
// effect on the API is the same as if we'd declared this method as taking
// |const nsTArray_Impl<E, OtherAlloc>&|.
explicit nsTArray_Impl(const self_type& aOther) { AppendElements(aOther); }
// Allow converting to a const array with a different kind of allocator,
// Since the allocator doesn't matter for const arrays
template<typename Allocator>
operator const nsTArray_Impl<E, Allocator>&() const
{
return *reinterpret_cast<const nsTArray_Impl<E, Allocator>*>(this);
}
// And we have to do this for our subclasses too
operator const nsTArray<E>&() const
{
return *reinterpret_cast<const InfallibleTArray<E>*>(this);
}
operator const FallibleTArray<E>&() const
{
return *reinterpret_cast<const FallibleTArray<E>*>(this);
}
// The array's assignment operator performs a 'deep' copy of the given
// array. It is optimized to reuse existing storage if possible.
// @param aOther The array object to copy.
self_type& operator=(const self_type& aOther)
{
if (this != &aOther) {
ReplaceElementsAt(0, Length(), aOther.Elements(), aOther.Length());
}
return *this;
}
// The array's move assignment operator steals the underlying data from
// the other array.
// @param other The array object to move from.
self_type& operator=(self_type&& aOther)
{
if (this != &aOther) {
Clear();
SwapElements(aOther);
}
return *this;
}
// Return true if this array has the same length and the same
// elements as |aOther|.
template<typename Allocator>
bool operator==(const nsTArray_Impl<E, Allocator>& aOther) const
{
size_type len = Length();
if (len != aOther.Length()) {
return false;
}
// XXX std::equal would be as fast or faster here
for (index_type i = 0; i < len; ++i) {
if (!(operator[](i) == aOther[i])) {
return false;
}
}
return true;
}
// Return true if this array does not have the same length and the same
// elements as |aOther|.
bool operator!=(const self_type& aOther) const { return !operator==(aOther); }
template<typename Allocator>
self_type& operator=(const nsTArray_Impl<E, Allocator>& aOther)
{
ReplaceElementsAt(0, Length(), aOther.Elements(), aOther.Length());
return *this;
}
template<typename Allocator>
self_type& operator=(nsTArray_Impl<E, Allocator>&& aOther)
{
Clear();
SwapElements(aOther);
return *this;
}
// @return The amount of memory used by this nsTArray_Impl, excluding
// sizeof(*this). If you want to measure anything hanging off the array, you
// must iterate over the elements and measure them individually; hence the
// "Shallow" prefix.
size_t ShallowSizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const
{
if (this->UsesAutoArrayBuffer() || Hdr() == EmptyHdr()) {
return 0;
}
return aMallocSizeOf(this->Hdr());
}
// @return The amount of memory used by this nsTArray_Impl, including
// sizeof(*this). If you want to measure anything hanging off the array, you
// must iterate over the elements and measure them individually; hence the
// "Shallow" prefix.
size_t ShallowSizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const
{
return aMallocSizeOf(this) + ShallowSizeOfExcludingThis(aMallocSizeOf);
}
//
// Accessor methods
//
// This method provides direct access to the array elements.
// @return A pointer to the first element of the array. If the array is
// empty, then this pointer must not be dereferenced.
elem_type* Elements() { return reinterpret_cast<elem_type*>(Hdr() + 1); }
// This method provides direct, readonly access to the array elements.
// @return A pointer to the first element of the array. If the array is
// empty, then this pointer must not be dereferenced.
const elem_type* Elements() const
{
return reinterpret_cast<const elem_type*>(Hdr() + 1);
}
// This method provides direct access to an element of the array. The given
// index must be within the array bounds.
// @param aIndex The index of an element in the array.
// @return A reference to the i'th element of the array.
elem_type& ElementAt(index_type aIndex)
{
MOZ_ASSERT(aIndex < Length(), "invalid array index");
return Elements()[aIndex];
}
// This method provides direct, readonly access to an element of the array
// The given index must be within the array bounds.
// @param aIndex The index of an element in the array.
// @return A const reference to the i'th element of the array.
const elem_type& ElementAt(index_type aIndex) const
{
MOZ_ASSERT(aIndex < Length(), "invalid array index");
return Elements()[aIndex];
}
// This method provides direct access to an element of the array in a bounds
// safe manner. If the requested index is out of bounds the provided default
// value is returned.
// @param aIndex The index of an element in the array.
// @param aDef The value to return if the index is out of bounds.
elem_type& SafeElementAt(index_type aIndex, elem_type& aDef)
{
return aIndex < Length() ? Elements()[aIndex] : aDef;
}
// This method provides direct access to an element of the array in a bounds
// safe manner. If the requested index is out of bounds the provided default
// value is returned.
// @param aIndex The index of an element in the array.
// @param aDef The value to return if the index is out of bounds.
const elem_type& SafeElementAt(index_type aIndex, const elem_type& aDef) const
{
return aIndex < Length() ? Elements()[aIndex] : aDef;
}
// Shorthand for ElementAt(aIndex)
elem_type& operator[](index_type aIndex) { return ElementAt(aIndex); }
// Shorthand for ElementAt(aIndex)
const elem_type& operator[](index_type aIndex) const { return ElementAt(aIndex); }
// Shorthand for ElementAt(length - 1)
elem_type& LastElement() { return ElementAt(Length() - 1); }
// Shorthand for ElementAt(length - 1)
const elem_type& LastElement() const { return ElementAt(Length() - 1); }
// Shorthand for SafeElementAt(length - 1, def)
elem_type& SafeLastElement(elem_type& aDef)
{
return SafeElementAt(Length() - 1, aDef);
}
// Shorthand for SafeElementAt(length - 1, def)
const elem_type& SafeLastElement(const elem_type& aDef) const
{
return SafeElementAt(Length() - 1, aDef);
}
// Methods for range-based for loops.
iterator begin() { return Elements(); }
const_iterator begin() const { return Elements(); }
const_iterator cbegin() const { return begin(); }
iterator end() { return Elements() + Length(); }
const_iterator end() const { return Elements() + 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(); }
//
// Search methods
//
// This method searches for the first element in this array that is equal
// to the given element.
// @param aItem The item to search for.
// @param aComp The Comparator used to determine element equality.
// @return true if the element was found.
template<class Item, class Comparator>
bool Contains(const Item& aItem, const Comparator& aComp) const
{
return IndexOf(aItem, 0, aComp) != NoIndex;
}
// This method searches for the first element in this array that is equal
// to the given element. This method assumes that 'operator==' is defined
// for elem_type.
// @param aItem The item to search for.
// @return true if the element was found.
template<class Item>
bool Contains(const Item& aItem) const
{
return IndexOf(aItem) != NoIndex;
}
// This method searches for the offset of the first element in this
// array that is equal to the given element.
// @param aItem The item to search for.
// @param aStart The index to start from.
// @param aComp The Comparator used to determine element equality.
// @return The index of the found element or NoIndex if not found.
template<class Item, class Comparator>
index_type IndexOf(const Item& aItem, index_type aStart,
const Comparator& aComp) const
{
const elem_type* iter = Elements() + aStart;
const elem_type* iend = Elements() + Length();
for (; iter != iend; ++iter) {
if (aComp.Equals(*iter, aItem)) {
return index_type(iter - Elements());
}
}
return NoIndex;
}
// This method searches for the offset of the first element in this
// array that is equal to the given element. This method assumes
// that 'operator==' is defined for elem_type.
// @param aItem The item to search for.
// @param aStart The index to start from.
// @return The index of the found element or NoIndex if not found.
template<class Item>
index_type IndexOf(const Item& aItem, index_type aStart = 0) const
{
return IndexOf(aItem, aStart, nsDefaultComparator<elem_type, Item>());
}
// This method searches for the offset of the last element in this
// array that is equal to the given element.
// @param aItem The item to search for.
// @param aStart The index to start from. If greater than or equal to the
// length of the array, then the entire array is searched.
// @param aComp The Comparator used to determine element equality.
// @return The index of the found element or NoIndex if not found.
template<class Item, class Comparator>
index_type LastIndexOf(const Item& aItem, index_type aStart,
const Comparator& aComp) const
{
size_type endOffset = aStart >= Length() ? Length() : aStart + 1;
const elem_type* iend = Elements() - 1;
const elem_type* iter = iend + endOffset;
for (; iter != iend; --iter) {
if (aComp.Equals(*iter, aItem)) {
return index_type(iter - Elements());
}
}
return NoIndex;
}
// This method searches for the offset of the last element in this
// array that is equal to the given element. This method assumes
// that 'operator==' is defined for elem_type.
// @param aItem The item to search for.
// @param aStart The index to start from. If greater than or equal to the
// length of the array, then the entire array is searched.
// @return The index of the found element or NoIndex if not found.
template<class Item>
index_type LastIndexOf(const Item& aItem,
index_type aStart = NoIndex) const
{
return LastIndexOf(aItem, aStart, nsDefaultComparator<elem_type, Item>());
}
// This method searches for the offset for the element in this array
// that is equal to the given element. The array is assumed to be sorted.
// If there is more than one equivalent element, there is no guarantee
// on which one will be returned.
// @param aItem The item to search for.
// @param aComp The Comparator used.
// @return The index of the found element or NoIndex if not found.
template<class Item, class Comparator>
index_type BinaryIndexOf(const Item& aItem, const Comparator& aComp) const
{
using mozilla::BinarySearchIf;
typedef ::detail::ItemComparatorEq<Item, Comparator> Cmp;
size_t index;
bool found = BinarySearchIf(*this, 0, Length(), Cmp(aItem, aComp), &index);
return found ? index : NoIndex;
}
// This method searches for the offset for the element in this array
// that is equal to the given element. The array is assumed to be sorted.
// This method assumes that 'operator==' and 'operator<' are defined.
// @param aItem The item to search for.
// @return The index of the found element or NoIndex if not found.
template<class Item>
index_type BinaryIndexOf(const Item& aItem) const
{
return BinaryIndexOf(aItem, nsDefaultComparator<elem_type, Item>());
}
//
// Mutation methods
//
template<class Allocator, typename ActualAlloc = Alloc>
typename ActualAlloc::ResultType Assign(
const nsTArray_Impl<E, Allocator>& aOther)
{
return ActualAlloc::ConvertBoolToResultType(
!!ReplaceElementsAt<E, ActualAlloc>(0, Length(),
aOther.Elements(), aOther.Length()));
}
template<class Allocator>
/* MOZ_WARN_UNUSED_RESULT */
bool Assign(const nsTArray_Impl<E, Allocator>& aOther,
const mozilla::fallible_t&)
{
return Assign<Allocator, FallibleAlloc>(aOther);
}
template<class Allocator>
void Assign(nsTArray_Impl<E, Allocator>&& aOther)
{
Clear();
SwapElements(aOther);
}
// This method call the destructor on each element of the array, empties it,
// but does not shrink the array's capacity.
// See also SetLengthAndRetainStorage.
// Make sure to call Compact() if needed to avoid keeping a huge array
// around.
void ClearAndRetainStorage()
{
if (base_type::mHdr == EmptyHdr()) {
return;
}
DestructRange(0, Length());
base_type::mHdr->mLength = 0;
}
// This method modifies the length of the array, but unlike SetLength
// it doesn't deallocate/reallocate the current internal storage.
// The new length MUST be shorter than or equal to the current capacity.
// If the new length is larger than the existing length of the array,
// then new elements will be constructed using elem_type's default
// constructor. If shorter, elements will be destructed and removed.
// See also ClearAndRetainStorage.
// @param aNewLen The desired length of this array.
void SetLengthAndRetainStorage(size_type aNewLen)
{
MOZ_ASSERT(aNewLen <= base_type::Capacity());
size_type oldLen = Length();
if (aNewLen > oldLen) {
InsertElementsAt(oldLen, aNewLen - oldLen);
return;
}
if (aNewLen < oldLen) {
DestructRange(aNewLen, oldLen - aNewLen);
base_type::mHdr->mLength = aNewLen;
}
}
// This method replaces a range of elements in this array.
// @param aStart The starting index of the elements to replace.
// @param aCount The number of elements to replace. This may be zero to
// insert elements without removing any existing elements.
// @param aArray The values to copy into this array. Must be non-null,
// and these elements must not already exist in the array
// being modified.
// @param aArrayLen The number of values to copy into this array.
// @return A pointer to the new elements in the array, or null if
// the operation failed due to insufficient memory.
protected:
template<class Item, typename ActualAlloc = Alloc>
elem_type* ReplaceElementsAt(index_type aStart, size_type aCount,
const Item* aArray, size_type aArrayLen)
{
// Adjust memory allocation up-front to catch errors.
if (!ActualAlloc::Successful(this->template EnsureCapacity<ActualAlloc>(
Length() + aArrayLen - aCount, sizeof(elem_type)))) {
return nullptr;
}
DestructRange(aStart, aCount);
this->template ShiftData<ActualAlloc>(aStart, aCount, aArrayLen,
sizeof(elem_type),
MOZ_ALIGNOF(elem_type));
AssignRange(aStart, aArrayLen, aArray);
return Elements() + aStart;
}
public:
template<class Item>
/* MOZ_WARN_UNUSED_RESULT */
elem_type* ReplaceElementsAt(index_type aStart, size_type aCount,
const Item* aArray, size_type aArrayLen,
const mozilla::fallible_t&)
{
return ReplaceElementsAt<Item, FallibleAlloc>(aStart, aCount,
aArray, aArrayLen);
}
// A variation on the ReplaceElementsAt method defined above.
protected:
template<class Item, typename ActualAlloc = Alloc>
elem_type* ReplaceElementsAt(index_type aStart, size_type aCount,
const nsTArray<Item>& aArray)
{
return ReplaceElementsAt<Item, ActualAlloc>(
aStart, aCount, aArray.Elements(), aArray.Length());
}
public:
template<class Item>
/* MOZ_WARN_UNUSED_RESULT */
elem_type* ReplaceElementsAt(index_type aStart, size_type aCount,
const nsTArray<Item>& aArray,
const mozilla::fallible_t&)
{
return ReplaceElementsAt<Item, FallibleAlloc>(aStart, aCount, aArray);
}
// A variation on the ReplaceElementsAt method defined above.
protected:
template<class Item, typename ActualAlloc = Alloc>
elem_type* ReplaceElementsAt(index_type aStart, size_type aCount,
const Item& aItem)
{
return ReplaceElementsAt<Item, ActualAlloc>(aStart, aCount, &aItem, 1);
}
public:
template<class Item>
/* MOZ_WARN_UNUSED_RESULT */
elem_type* ReplaceElementsAt(index_type aStart, size_type aCount,
const Item& aItem, const mozilla::fallible_t&)
{
return ReplaceElementsAt<Item, FallibleAlloc>(aStart, aCount, aItem);
}
// A variation on the ReplaceElementsAt method defined above.
template<class Item>
elem_type* ReplaceElementAt(index_type aIndex, const Item& aItem)
{
return ReplaceElementsAt(aIndex, 1, &aItem, 1);
}
// A variation on the ReplaceElementsAt method defined above.
protected:
template<class Item, typename ActualAlloc = Alloc>
elem_type* InsertElementsAt(index_type aIndex, const Item* aArray,
size_type aArrayLen)
{
return ReplaceElementsAt<Item, ActualAlloc>(aIndex, 0, aArray, aArrayLen);
}
public:
template<class Item>
/* MOZ_WARN_UNUSED_RESULT */
elem_type* InsertElementsAt(index_type aIndex, const Item* aArray,
size_type aArrayLen, const mozilla::fallible_t&)
{
return InsertElementsAt<Item, FallibleAlloc>(aIndex, aArray, aArrayLen);
}
// A variation on the ReplaceElementsAt method defined above.
protected:
template<class Item, class Allocator, typename ActualAlloc = Alloc>
elem_type* InsertElementsAt(index_type aIndex,
const nsTArray_Impl<Item, Allocator>& aArray)
{
return ReplaceElementsAt<Item, ActualAlloc>(
aIndex, 0, aArray.Elements(), aArray.Length());
}
public:
template<class Item, class Allocator>
/* MOZ_WARN_UNUSED_RESULT */
elem_type* InsertElementsAt(index_type aIndex,
const nsTArray_Impl<Item, Allocator>& aArray,
const mozilla::fallible_t&)
{
return InsertElementsAt<Item, Allocator, FallibleAlloc>(aIndex, aArray);
}
// Insert a new element without copy-constructing. This is useful to avoid
// temporaries.
// @return A pointer to the newly inserted element, or null on OOM.
protected:
template<typename ActualAlloc = Alloc>
elem_type* InsertElementAt(index_type aIndex)
{
if (!ActualAlloc::Successful(this->template EnsureCapacity<ActualAlloc>(
Length() + 1, sizeof(elem_type)))) {
return nullptr;
}
this->template ShiftData<ActualAlloc>(aIndex, 0, 1, sizeof(elem_type),
MOZ_ALIGNOF(elem_type));
elem_type* elem = Elements() + aIndex;
elem_traits::Construct(elem);
return elem;
}
public:
/* MOZ_WARN_UNUSED_RESULT */
elem_type* InsertElementAt(index_type aIndex, const mozilla::fallible_t&)
{
return InsertElementAt<FallibleAlloc>(aIndex);
}
// Insert a new element, move constructing if possible.
protected:
template<class Item, typename ActualAlloc = Alloc>
elem_type* InsertElementAt(index_type aIndex, Item&& aItem)
{
if (!ActualAlloc::Successful(this->template EnsureCapacity<ActualAlloc>(
Length() + 1, sizeof(elem_type)))) {
return nullptr;
}
this->template ShiftData<ActualAlloc>(aIndex, 0, 1, sizeof(elem_type),
MOZ_ALIGNOF(elem_type));
elem_type* elem = Elements() + aIndex;
elem_traits::Construct(elem, mozilla::Forward<Item>(aItem));
return elem;
}
public:
template<class Item>
/* MOZ_WARN_UNUSED_RESULT */
elem_type* InsertElementAt(index_type aIndex, Item&& aItem,
const mozilla::fallible_t&)
{
return InsertElementAt<Item, FallibleAlloc>(aIndex,
mozilla::Forward<Item>(aItem));
}
// This method searches for the smallest index of an element that is strictly
// greater than |aItem|. If |aItem| is inserted at this index, the array will
// remain sorted and |aItem| would come after all elements that are equal to
// it. If |aItem| is greater than or equal to all elements in the array, the
// array length is returned.
//
// Note that consumers who want to know whether there are existing items equal
// to |aItem| in the array can just check that the return value here is > 0
// and indexing into the previous slot gives something equal to |aItem|.
//
//
// @param aItem The item to search for.
// @param aComp The Comparator used.
// @return The index of greatest element <= to |aItem|
// @precondition The array is sorted
template<class Item, class Comparator>
index_type IndexOfFirstElementGt(const Item& aItem,
const Comparator& aComp) const
{
using mozilla::BinarySearchIf;
typedef ::detail::ItemComparatorFirstElementGT<Item, Comparator> Cmp;
size_t index;
BinarySearchIf(*this, 0, Length(), Cmp(aItem, aComp), &index);
return index;
}
// A variation on the IndexOfFirstElementGt method defined above.
template<class Item>
index_type
IndexOfFirstElementGt(const Item& aItem) const
{
return IndexOfFirstElementGt(aItem, nsDefaultComparator<elem_type, Item>());
}
// Inserts |aItem| at such an index to guarantee that if the array
// was previously sorted, it will remain sorted after this
// insertion.
protected:
template<class Item, class Comparator, typename ActualAlloc = Alloc>
elem_type* InsertElementSorted(Item&& aItem, const Comparator& aComp)
{
index_type index = IndexOfFirstElementGt<Item, Comparator>(aItem, aComp);
return InsertElementAt<Item, ActualAlloc>(
index, mozilla::Forward<Item>(aItem));
}
public:
template<class Item, class Comparator>
/* MOZ_WARN_UNUSED_RESULT */
elem_type* InsertElementSorted(Item&& aItem, const Comparator& aComp,
const mozilla::fallible_t&)
{
return InsertElementSorted<Item, Comparator, FallibleAlloc>(
mozilla::Forward<Item>(aItem), aComp);
}
// A variation on the InsertElementSorted method defined above.
protected:
template<class Item, typename ActualAlloc = Alloc>
elem_type* InsertElementSorted(Item&& aItem)
{
nsDefaultComparator<elem_type, Item> comp;
return InsertElementSorted<Item, decltype(comp), ActualAlloc>(
mozilla::Forward<Item>(aItem), comp);
}
public:
template<class Item>
/* MOZ_WARN_UNUSED_RESULT */
elem_type* InsertElementSorted(Item&& aItem, const mozilla::fallible_t&)
{
return InsertElementSorted<Item, FallibleAlloc>(
mozilla::Forward<Item>(aItem));
}
// This method appends elements to the end of this array.
// @param aArray The elements to append to this array.
// @param aArrayLen The number of elements to append to this array.
// @return A pointer to the new elements in the array, or null if
// the operation failed due to insufficient memory.
protected:
template<class Item, typename ActualAlloc = Alloc>
elem_type* AppendElements(const Item* aArray, size_type aArrayLen)
{
if (!ActualAlloc::Successful(this->template EnsureCapacity<ActualAlloc>(
Length() + aArrayLen, sizeof(elem_type)))) {
return nullptr;
}
index_type len = Length();
AssignRange(len, aArrayLen, aArray);
this->IncrementLength(aArrayLen);
return Elements() + len;
}
public:
template<class Item>
/* MOZ_WARN_UNUSED_RESULT */
elem_type* AppendElements(const Item* aArray, size_type aArrayLen,
const mozilla::fallible_t&)
{
return AppendElements<Item, FallibleAlloc>(aArray, aArrayLen);
}
// A variation on the AppendElements method defined above.
protected:
template<class Item, class Allocator, typename ActualAlloc = Alloc>
elem_type* AppendElements(const nsTArray_Impl<Item, Allocator>& aArray)
{
return AppendElements<Item, ActualAlloc>(aArray.Elements(), aArray.Length());
}
public:
template<class Item, class Allocator>
/* MOZ_WARN_UNUSED_RESULT */
elem_type* AppendElements(const nsTArray_Impl<Item, Allocator>& aArray,
const mozilla::fallible_t&)
{
return AppendElements<Item, Allocator, FallibleAlloc>(aArray);
}
// Move all elements from another array to the end of this array.
// @return A pointer to the newly appended elements, or null on OOM.
template<class Item, class Allocator>
elem_type* AppendElements(nsTArray_Impl<Item, Allocator>&& aArray)
{
MOZ_ASSERT(&aArray != this, "argument must be different aArray");
if (Length() == 0) {
SwapElements(aArray);
return Elements();
}
index_type len = Length();
index_type otherLen = aArray.Length();
if (!Alloc::Successful(this->template EnsureCapacity<Alloc>(
len + otherLen, sizeof(elem_type)))) {
return nullptr;
}
copy_type::CopyElements(Elements() + len, aArray.Elements(), otherLen,
sizeof(elem_type));
this->IncrementLength(otherLen);
aArray.template ShiftData<Alloc>(0, otherLen, 0, sizeof(elem_type),
MOZ_ALIGNOF(elem_type));
return Elements() + len;
}
// Append a new element, move constructing if possible.
protected:
template<class Item, typename ActualAlloc = Alloc>
elem_type* AppendElement(Item&& aItem)
{
if (!ActualAlloc::Successful(this->template EnsureCapacity<ActualAlloc>(
Length() + 1, sizeof(elem_type)))) {
return nullptr;
}
elem_type* elem = Elements() + Length();
elem_traits::Construct(elem, mozilla::Forward<Item>(aItem));
this->IncrementLength(1);
return elem;
}
public:
template<class Item>
/* MOZ_WARN_UNUSED_RESULT */
elem_type* AppendElement(Item&& aItem,
const mozilla::fallible_t&)
{
return AppendElement<Item, FallibleAlloc>(mozilla::Forward<Item>(aItem));
}
// Append new elements without copy-constructing. This is useful to avoid
// temporaries.
// @return A pointer to the newly appended elements, or null on OOM.
protected:
template<typename ActualAlloc = Alloc>
elem_type* AppendElements(size_type aCount) {
if (!ActualAlloc::Successful(this->template EnsureCapacity<ActualAlloc>(
Length() + aCount, sizeof(elem_type)))) {
return nullptr;
}
elem_type* elems = Elements() + Length();
size_type i;
for (i = 0; i < aCount; ++i) {
elem_traits::Construct(elems + i);
}
this->IncrementLength(aCount);
return elems;
}
public:
/* MOZ_WARN_UNUSED_RESULT */
elem_type* AppendElements(size_type aCount,
const mozilla::fallible_t&)
{
return AppendElements<FallibleAlloc>(aCount);
}
// Append a new element without copy-constructing. This is useful to avoid
// temporaries.
// @return A pointer to the newly appended element, or null on OOM.
protected:
template<typename ActualAlloc = Alloc>
elem_type* AppendElement()
{
return AppendElements<ActualAlloc>(1);
}
public:
/* MOZ_WARN_UNUSED_RESULT */
elem_type* AppendElement(const mozilla::fallible_t&)
{
return AppendElement<FallibleAlloc>();
}
// This method removes a range of elements from this array.
// @param aStart The starting index of the elements to remove.
// @param aCount The number of elements to remove.
void RemoveElementsAt(index_type aStart, size_type aCount)
{
MOZ_ASSERT(aCount == 0 || aStart < Length(), "Invalid aStart index");
MOZ_ASSERT(aStart + aCount <= Length(), "Invalid length");
// Check that the previous assert didn't overflow
MOZ_ASSERT(aStart <= aStart + aCount, "Start index plus length overflows");
DestructRange(aStart, aCount);
this->template ShiftData<Alloc>(aStart, aCount, 0,
sizeof(elem_type), MOZ_ALIGNOF(elem_type));
}
// A variation on the RemoveElementsAt method defined above.
void RemoveElementAt(index_type aIndex) { RemoveElementsAt(aIndex, 1); }
// A variation on the RemoveElementsAt method defined above.
void Clear() { RemoveElementsAt(0, Length()); }
// This helper function combines IndexOf with RemoveElementAt to "search
// and destroy" the first element that is equal to the given element.
// @param aItem The item to search for.
// @param aComp The Comparator used to determine element equality.
// @return true if the element was found
template<class Item, class Comparator>
bool RemoveElement(const Item& aItem, const Comparator& aComp)
{
index_type i = IndexOf(aItem, 0, aComp);
if (i == NoIndex) {
return false;
}
RemoveElementAt(i);
return true;
}
// A variation on the RemoveElement method defined above that assumes
// that 'operator==' is defined for elem_type.
template<class Item>
bool RemoveElement(const Item& aItem)
{
return RemoveElement(aItem, nsDefaultComparator<elem_type, Item>());
}
// This helper function combines IndexOfFirstElementGt with
// RemoveElementAt to "search and destroy" the last element that
// is equal to the given element.
// @param aItem The item to search for.
// @param aComp The Comparator used to determine element equality.
// @return true if the element was found
template<class Item, class Comparator>
bool RemoveElementSorted(const Item& aItem, const Comparator& aComp)
{
index_type index = IndexOfFirstElementGt(aItem, aComp);
if (index > 0 && aComp.Equals(ElementAt(index - 1), aItem)) {
RemoveElementAt(index - 1);
return true;
}
return false;
}
// A variation on the RemoveElementSorted method defined above.
template<class Item>
bool RemoveElementSorted(const Item& aItem)
{
return RemoveElementSorted(aItem, nsDefaultComparator<elem_type, Item>());
}
// This method causes the elements contained in this array and the given
// array to be swapped.
template<class Allocator>
typename Alloc::ResultType SwapElements(nsTArray_Impl<E, Allocator>& aOther)
{
return Alloc::Result(this->template SwapArrayElements<Alloc>(
aOther, sizeof(elem_type), MOZ_ALIGNOF(elem_type)));
}
//
// Allocation
//
// This method may increase the capacity of this array object by the
// specified amount. This method may be called in advance of several
// AppendElement operations to minimize heap re-allocations. This method
// will not reduce the number of elements in this array.
// @param aCapacity The desired capacity of this array.
// @return True if the operation succeeded; false if we ran out of memory
protected:
template<typename ActualAlloc = Alloc>
typename ActualAlloc::ResultType SetCapacity(size_type aCapacity)
{
return ActualAlloc::Result(this->template EnsureCapacity<ActualAlloc>(
aCapacity, sizeof(elem_type)));
}
public:
/* MOZ_WARN_UNUSED_RESULT */
bool SetCapacity(size_type aCapacity, const mozilla::fallible_t&)
{
return SetCapacity<FallibleAlloc>(aCapacity);
}
// This method modifies the length of the array. If the new length is
// larger than the existing length of the array, then new elements will be
// constructed using elem_type's default constructor. Otherwise, this call
// removes elements from the array (see also RemoveElementsAt).
// @param aNewLen The desired length of this array.
// @return True if the operation succeeded; false otherwise.
// See also TruncateLength if the new length is guaranteed to be smaller than
// the old.
protected:
template<typename ActualAlloc = Alloc>
typename ActualAlloc::ResultType SetLength(size_type aNewLen)
{
size_type oldLen = Length();
if (aNewLen > oldLen) {
return ActualAlloc::ConvertBoolToResultType(
InsertElementsAt<ActualAlloc>(oldLen, aNewLen - oldLen) != nullptr);
}
TruncateLength(aNewLen);
return ActualAlloc::ConvertBoolToResultType(true);
}
public:
/* MOZ_WARN_UNUSED_RESULT */
bool SetLength(size_type aNewLen, const mozilla::fallible_t&)
{
return SetLength<FallibleAlloc>(aNewLen);
}
// This method modifies the length of the array, but may only be
// called when the new length is shorter than the old. It can
// therefore be called when elem_type has no default constructor,
// unlike SetLength. It removes elements from the array (see also
// RemoveElementsAt).
// @param aNewLen The desired length of this array.
void TruncateLength(size_type aNewLen)
{
size_type oldLen = Length();
MOZ_ASSERT(aNewLen <= oldLen,
"caller should use SetLength instead");
RemoveElementsAt(aNewLen, oldLen - aNewLen);
}
// This method ensures that the array has length at least the given
// length. If the current length is shorter than the given length,
// then new elements will be constructed using elem_type's default
// constructor.
// @param aMinLen The desired minimum length of this array.
// @return True if the operation succeeded; false otherwise.
protected:
template<typename ActualAlloc = Alloc>
typename ActualAlloc::ResultType EnsureLengthAtLeast(size_type aMinLen)
{
size_type oldLen = Length();
if (aMinLen > oldLen) {
return ActualAlloc::ConvertBoolToResultType(
!!InsertElementsAt<ActualAlloc>(oldLen, aMinLen - oldLen));
}
return ActualAlloc::ConvertBoolToResultType(true);
}
public:
/* MOZ_WARN_UNUSED_RESULT */
bool EnsureLengthAtLeast(size_type aMinLen, const mozilla::fallible_t&)
{
return EnsureLengthAtLeast<FallibleAlloc>(aMinLen);
}
// This method inserts elements into the array, constructing
// them using elem_type's default constructor.
// @param aIndex the place to insert the new elements. This must be no
// greater than the current length of the array.
// @param aCount the number of elements to insert
protected:
template<typename ActualAlloc = Alloc>
elem_type* InsertElementsAt(index_type aIndex, size_type aCount)
{
if (!base_type::template InsertSlotsAt<ActualAlloc>(aIndex, aCount,
sizeof(elem_type),
MOZ_ALIGNOF(elem_type))) {
return nullptr;
}
// Initialize the extra array elements
elem_type* iter = Elements() + aIndex;
elem_type* iend = iter + aCount;
for (; iter != iend; ++iter) {
elem_traits::Construct(iter);
}
return Elements() + aIndex;
}
public:
/* MOZ_WARN_UNUSED_RESULT */
elem_type* InsertElementsAt(index_type aIndex, size_type aCount,
const mozilla::fallible_t&)
{
return InsertElementsAt<FallibleAlloc>(aIndex, aCount);
}
// This method inserts elements into the array, constructing them
// elem_type's copy constructor (or whatever one-arg constructor
// happens to match the Item type).
// @param aIndex the place to insert the new elements. This must be no
// greater than the current length of the array.
// @param aCount the number of elements to insert.
// @param aItem the value to use when constructing the new elements.
protected:
template<class Item, typename ActualAlloc = Alloc>
elem_type* InsertElementsAt(index_type aIndex, size_type aCount,
const Item& aItem)
{
if (!base_type::template InsertSlotsAt<ActualAlloc>(aIndex, aCount,
sizeof(elem_type),
MOZ_ALIGNOF(elem_type))) {
return nullptr;
}
// Initialize the extra array elements
elem_type* iter = Elements() + aIndex;
elem_type* iend = iter + aCount;
for (; iter != iend; ++iter) {
elem_traits::Construct(iter, aItem);
}
return Elements() + aIndex;
}
public:
template<class Item>
/* MOZ_WARN_UNUSED_RESULT */
elem_type* InsertElementsAt(index_type aIndex, size_type aCount,
const Item& aItem, const mozilla::fallible_t&)
{
return InsertElementsAt<Item, FallibleAlloc>(aIndex, aCount, aItem);
}
// This method may be called to minimize the memory used by this array.
void Compact()
{
this->template ShrinkCapacity<Alloc>(sizeof(elem_type),
MOZ_ALIGNOF(elem_type));
}
//
// Sorting
//
// This function is meant to be used with the NS_QuickSort function. It
// maps the callback API expected by NS_QuickSort to the Comparator API
// used by nsTArray_Impl. See nsTArray_Impl::Sort.
template<class Comparator>
static int Compare(const void* aE1, const void* aE2, void* aData)
{
const Comparator* c = reinterpret_cast<const Comparator*>(aData);
const elem_type* a = static_cast<const elem_type*>(aE1);
const elem_type* b = static_cast<const elem_type*>(aE2);
return c->LessThan(*a, *b) ? -1 : (c->Equals(*a, *b) ? 0 : 1);
}
// This method sorts the elements of the array. It uses the LessThan
// method defined on the given Comparator object to collate elements.
// @param aComp The Comparator used to collate elements.
template<class Comparator>
void Sort(const Comparator& aComp)
{
NS_QuickSort(Elements(), Length(), sizeof(elem_type),
Compare<Comparator>, const_cast<Comparator*>(&aComp));
}
// A variation on the Sort method defined above that assumes that
// 'operator<' is defined for elem_type.
void Sort() { Sort(nsDefaultComparator<elem_type, elem_type>()); }
//
// Binary Heap
//
// Sorts the array into a binary heap.
// @param aComp The Comparator used to create the heap
template<class Comparator>
void MakeHeap(const Comparator& aComp)
{
if (!Length()) {
return;
}
index_type index = (Length() - 1) / 2;
do {
SiftDown(index, aComp);
} while (index--);
}
// A variation on the MakeHeap method defined above.
void MakeHeap()
{
MakeHeap(nsDefaultComparator<elem_type, elem_type>());
}
// Adds an element to the heap
// @param aItem The item to add
// @param aComp The Comparator used to sift-up the item
template<class Item, class Comparator>
elem_type* PushHeap(const Item& aItem, const Comparator& aComp)
{
if (!base_type::template InsertSlotsAt<Alloc>(Length(), 1, sizeof(elem_type),
MOZ_ALIGNOF(elem_type))) {
return nullptr;
}
// Sift up the new node
elem_type* elem = Elements();
index_type index = Length() - 1;
index_type parent_index = (index - 1) / 2;
while (index && aComp.LessThan(elem[parent_index], aItem)) {
elem[index] = elem[parent_index];
index = parent_index;
parent_index = (index - 1) / 2;
}
elem[index] = aItem;
return &elem[index];
}
// A variation on the PushHeap method defined above.
template<class Item>
elem_type* PushHeap(const Item& aItem)
{
return PushHeap(aItem, nsDefaultComparator<elem_type, Item>());
}
// Delete the root of the heap and restore the heap
// @param aComp The Comparator used to restore the heap
template<class Comparator>
void PopHeap(const Comparator& aComp)
{
if (!Length()) {
return;
}
index_type last_index = Length() - 1;
elem_type* elem = Elements();
elem[0] = elem[last_index];
TruncateLength(last_index);
if (Length()) {
SiftDown(0, aComp);
}
}
// A variation on the PopHeap method defined above.
void PopHeap()
{
PopHeap(nsDefaultComparator<elem_type, elem_type>());
}
protected:
using base_type::Hdr;
using base_type::ShrinkCapacity;
// This method invokes elem_type's destructor on a range of elements.
// @param aStart The index of the first element to destroy.
// @param aCount The number of elements to destroy.
void DestructRange(index_type aStart, size_type aCount)
{
elem_type* iter = Elements() + aStart;
elem_type *iend = iter + aCount;
for (; iter != iend; ++iter) {
elem_traits::Destruct(iter);
}
}
// This method invokes elem_type's copy-constructor on a range of elements.
// @param aStart The index of the first element to construct.
// @param aCount The number of elements to construct.
// @param aValues The array of elements to copy.
template<class Item>
void AssignRange(index_type aStart, size_type aCount, const Item* aValues)
{
AssignRangeAlgorithm<mozilla::IsPod<Item>::value,
mozilla::IsSame<Item, elem_type>::value>
::implementation(Elements(), aStart, aCount, aValues);
}
// This method sifts an item down to its proper place in a binary heap
// @param aIndex The index of the node to start sifting down from
// @param aComp The Comparator used to sift down
template<class Comparator>
void SiftDown(index_type aIndex, const Comparator& aComp)
{
elem_type* elem = Elements();
elem_type item = elem[aIndex];
index_type iend = Length() - 1;
while ((aIndex * 2) < iend) {
const index_type left = (aIndex * 2) + 1;
const index_type right = (aIndex * 2) + 2;
const index_type parent_index = aIndex;
if (aComp.LessThan(item, elem[left])) {
if (left < iend &&
aComp.LessThan(elem[left], elem[right])) {
aIndex = right;
} else {
aIndex = left;
}
} else if (left < iend &&
aComp.LessThan(item, elem[right])) {
aIndex = right;
} else {
break;
}
elem[parent_index] = elem[aIndex];
}
elem[aIndex] = item;
}
};
template<typename E, typename Alloc>
inline void
ImplCycleCollectionUnlink(nsTArray_Impl<E, Alloc>& aField)
{
aField.Clear();
}
template<typename E, typename Alloc>
inline void
ImplCycleCollectionTraverse(nsCycleCollectionTraversalCallback& aCallback,
nsTArray_Impl<E, Alloc>& aField,
const char* aName,
uint32_t aFlags = 0)
{
aFlags |= CycleCollectionEdgeNameArrayFlag;
size_t length = aField.Length();
for (size_t i = 0; i < length; ++i) {
ImplCycleCollectionTraverse(aCallback, aField[i], aName, aFlags);
}
}
//
// nsTArray is an infallible vector class. See the comment at the top of this
// file for more details.
//
template<class E>
class nsTArray : public nsTArray_Impl<E, nsTArrayInfallibleAllocator>
{
public:
typedef nsTArray_Impl<E, nsTArrayInfallibleAllocator> base_type;
typedef nsTArray<E> self_type;
typedef typename base_type::size_type size_type;
nsTArray() {}
explicit nsTArray(size_type aCapacity) : base_type(aCapacity) {}
explicit nsTArray(const nsTArray& aOther) : base_type(aOther) {}
MOZ_IMPLICIT nsTArray(nsTArray&& aOther) : base_type(mozilla::Move(aOther)) {}
template<class Allocator>
explicit nsTArray(const nsTArray_Impl<E, Allocator>& aOther)
: base_type(aOther)
{
}
template<class Allocator>
MOZ_IMPLICIT nsTArray(nsTArray_Impl<E, Allocator>&& aOther)
: base_type(mozilla::Move(aOther))
{
}
self_type& operator=(const self_type& aOther)
{
base_type::operator=(aOther);
return *this;
}
template<class Allocator>
self_type& operator=(const nsTArray_Impl<E, Allocator>& aOther)
{
base_type::operator=(aOther);
return *this;
}
self_type& operator=(self_type&& aOther)
{
base_type::operator=(mozilla::Move(aOther));
return *this;
}
template<class Allocator>
self_type& operator=(nsTArray_Impl<E, Allocator>&& aOther)
{
base_type::operator=(mozilla::Move(aOther));
return *this;
}
using base_type::AppendElement;
using base_type::AppendElements;
using base_type::EnsureLengthAtLeast;
using base_type::InsertElementAt;
using base_type::InsertElementsAt;
using base_type::InsertElementSorted;
using base_type::ReplaceElementsAt;
using base_type::SetCapacity;
using base_type::SetLength;
};
//
// FallibleTArray is a fallible vector class.
//
template<class E>
class FallibleTArray : public nsTArray_Impl<E, nsTArrayFallibleAllocator>
{
public:
typedef nsTArray_Impl<E, nsTArrayFallibleAllocator> base_type;
typedef FallibleTArray<E> self_type;
typedef typename base_type::size_type size_type;
FallibleTArray() {}
explicit FallibleTArray(size_type aCapacity) : base_type(aCapacity) {}
explicit FallibleTArray(const FallibleTArray<E>& aOther) : base_type(aOther) {}
explicit FallibleTArray(FallibleTArray<E>&& aOther)
: base_type(mozilla::Move(aOther))
{
}
template<class Allocator>
explicit FallibleTArray(const nsTArray_Impl<E, Allocator>& aOther)
: base_type(aOther)
{
}
template<class Allocator>
explicit FallibleTArray(nsTArray_Impl<E, Allocator>&& aOther)
: base_type(mozilla::Move(aOther))
{
}
self_type& operator=(const self_type& aOther)
{
base_type::operator=(aOther);
return *this;
}
template<class Allocator>
self_type& operator=(const nsTArray_Impl<E, Allocator>& aOther)
{
base_type::operator=(aOther);
return *this;
}
self_type& operator=(self_type&& aOther)
{
base_type::operator=(mozilla::Move(aOther));
return *this;
}
template<class Allocator>
self_type& operator=(nsTArray_Impl<E, Allocator>&& aOther)
{
base_type::operator=(mozilla::Move(aOther));
return *this;
}
};
//
// nsAutoArrayBase is a base class for AutoFallibleTArray and nsAutoTArray.
// You shouldn't use this class directly.
//
template<class TArrayBase, size_t N>
class MOZ_NON_MEMMOVABLE nsAutoArrayBase : public TArrayBase
{
static_assert(N != 0, "nsAutoArrayBase<TArrayBase, 0> should be specialized");
public:
typedef nsAutoArrayBase<TArrayBase, N> self_type;
typedef TArrayBase base_type;
typedef typename base_type::Header Header;
typedef typename base_type::elem_type elem_type;
template<typename Allocator>
self_type& operator=(const nsTArray_Impl<elem_type, Allocator>& aOther)
{
base_type::operator=(aOther);
return *this;
}
protected:
nsAutoArrayBase() { Init(); }
// We need this constructor because nsAutoTArray and friends all have
// implicit copy-constructors. If we don't have this method, those
// copy-constructors will call nsAutoArrayBase's implicit copy-constructor,
// which won't call Init() and set up the auto buffer!
nsAutoArrayBase(const self_type& aOther)
{
Init();
this->AppendElements(aOther);
}
explicit nsAutoArrayBase(const TArrayBase &aOther)
{
Init();
this->AppendElements(aOther);
}
template<typename Allocator>
explicit nsAutoArrayBase(nsTArray_Impl<elem_type, Allocator>&& aOther)
{
Init();
this->SwapElements(aOther);
}
private:
// nsTArray_base casts itself as an nsAutoArrayBase in order to get a pointer
// to mAutoBuf.
template<class Allocator, class Copier>
friend class nsTArray_base;
void Init()
{
static_assert(MOZ_ALIGNOF(elem_type) <= 8,
"can't handle alignments greater than 8, "
"see nsTArray_base::UsesAutoArrayBuffer()");
// Temporary work around for VS2012 RC compiler crash
Header** phdr = base_type::PtrToHdr();
*phdr = reinterpret_cast<Header*>(&mAutoBuf);
(*phdr)->mLength = 0;
(*phdr)->mCapacity = N;
(*phdr)->mIsAutoArray = 1;
MOZ_ASSERT(base_type::GetAutoArrayBuffer(MOZ_ALIGNOF(elem_type)) ==
reinterpret_cast<Header*>(&mAutoBuf),
"GetAutoArrayBuffer needs to be fixed");
}
// Declare mAutoBuf aligned to the maximum of the header's alignment and
// elem_type's alignment. We need to use a union rather than
// MOZ_ALIGNED_DECL because GCC is picky about what goes into
// __attribute__((aligned(foo))).
union
{
char mAutoBuf[sizeof(nsTArrayHeader) + N * sizeof(elem_type)];
// Do the max operation inline to ensure that it is a compile-time constant.
mozilla::AlignedElem<(MOZ_ALIGNOF(Header) > MOZ_ALIGNOF(elem_type)) ?
MOZ_ALIGNOF(Header) : MOZ_ALIGNOF(elem_type)> mAlign;
};
};
//
// Specialization of nsAutoArrayBase<TArrayBase, N> for the case where N == 0.
// nsAutoArrayBase<TArrayBase, 0> behaves exactly like TArrayBase, but without
// this specialization, it stores a useless inline header.
//
// We do have many nsAutoArrayBase<TArrayBase, 0> objects in memory: about
// 2,000 per tab as of May 2014. These are typically not explicitly
// nsAutoArrayBase<TArrayBase, 0> but rather nsAutoArrayBase<TArrayBase, N>
// for some value N depending on template parameters, in generic code.
//
// For that reason, we optimize this case with the below partial specialization,
// which ensures that nsAutoArrayBase<TArrayBase, 0> is just like TArrayBase,
// without any inline header overhead.
//
template<class TArrayBase>
class nsAutoArrayBase<TArrayBase, 0> : public TArrayBase
{
};
//
// nsAutoTArray<E, N> is an infallible vector class with N elements of inline
// storage. If you try to store more than N elements inside an
// nsAutoTArray<E, N>, we'll call malloc() and store them all on the heap.
//
// Note that you can cast an nsAutoTArray<E, N> to
// |const AutoFallibleTArray<E, N>&|.
//
template<class E, size_t N>
class nsAutoTArray : public nsAutoArrayBase<nsTArray<E>, N>
{
typedef nsAutoTArray<E, N> self_type;
typedef nsAutoArrayBase<nsTArray<E>, N> Base;
public:
nsAutoTArray() {}
template<typename Allocator>
explicit nsAutoTArray(const nsTArray_Impl<E, Allocator>& aOther)
{
Base::AppendElements(aOther);
}
template<typename Allocator>
explicit nsAutoTArray(nsTArray_Impl<E, Allocator>&& aOther)
: Base(mozilla::Move(aOther))
{
}
template<typename Allocator>
self_type& operator=(const nsTArray_Impl<E, Allocator>& other)
{
Base::operator=(other);
return *this;
}
operator const AutoFallibleTArray<E, N>&() const
{
return *reinterpret_cast<const AutoFallibleTArray<E, N>*>(this);
}
};
//
// AutoFallibleTArray<E, N> is a fallible vector class with N elements of
// inline storage.
//
template<class E, size_t N>
class AutoFallibleTArray : public nsAutoArrayBase<FallibleTArray<E>, N>
{
typedef AutoFallibleTArray<E, N> self_type;
typedef nsAutoArrayBase<FallibleTArray<E>, N> Base;
public:
AutoFallibleTArray() {}
template<typename Allocator>
explicit AutoFallibleTArray(const nsTArray_Impl<E, Allocator>& aOther)
{
Base::AppendElements(aOther);
}
template<typename Allocator>
explicit AutoFallibleTArray(nsTArray_Impl<E, Allocator>&& aOther)
: Base(mozilla::Move(aOther))
{
}
template<typename Allocator>
self_type& operator=(const nsTArray_Impl<E, Allocator>& other)
{
Base::operator=(other);
return *this;
}
operator const nsAutoTArray<E, N>&() const
{
return *reinterpret_cast<const nsAutoTArray<E, N>*>(this);
}
};
template<class E, size_t N>
struct nsTArray_CopyChooser<nsAutoTArray<E, N>>
{
typedef nsTArray_CopyWithConstructors<nsAutoTArray<E, N>> Type;
};
// Assert that nsAutoTArray doesn't have any extra padding inside.
//
// It's important that the data stored in this auto array takes up a multiple of
// 8 bytes; e.g. nsAutoTArray<uint32_t, 1> wouldn't work. Since nsAutoTArray
// contains a pointer, its size must be a multiple of alignof(void*). (This is
// because any type may be placed into an array, and there's no padding between
// elements of an array.) The compiler pads the end of the structure to
// enforce this rule.
//
// If we used nsAutoTArray<uint32_t, 1> below, this assertion would fail on a
// 64-bit system, where the compiler inserts 4 bytes of padding at the end of
// the auto array to make its size a multiple of alignof(void*) == 8 bytes.
static_assert(sizeof(nsAutoTArray<uint32_t, 2>) ==
sizeof(void*) + sizeof(nsTArrayHeader) + sizeof(uint32_t) * 2,
"nsAutoTArray shouldn't contain any extra padding, "
"see the comment");
// Definitions of nsTArray_Impl methods
#include "nsTArray-inl.h"
#endif // nsTArray_h__
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