gecko-dev/xpcom/glue/nsCOMArray.h
Nicholas Nethercote 2abcf180f1 Bug 1249171 - Simplify nsCOMArray::SizeOfExcludingThis(). r=erahm.
Using explicit iteration at measurement sites is much simpler and nicer than
using callbacks.

--HG--
extra : rebase_source : 8b3f7aa702743b665383766b66a866a2c3d17240
2016-02-19 14:54:45 +11:00

464 lines
14 KiB
C++

/* -*- 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/MemoryReporting.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);
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);
bool 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);
}
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:
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
bool ReplaceObjectAt(T* aObject, int32_t aIndex)
{
return nsCOMArray_base::ReplaceObjectAt(aObject, aIndex);
}
// nsTArray-compatible version
void ReplaceElementAt(uint32_t aIndex, T* aElement)
{
nsCOMArray_base::ReplaceElementAt(aIndex, aElement);
}
// Enumerator callback function. Return false to stop
// Here's a more readable form:
// bool enumerate(T* aElement, void* aData)
typedef bool (*nsCOMArrayEnumFunc)(T* aElement, void* aData);
// enumerate through the array with a callback.
bool EnumerateForwards(nsCOMArrayEnumFunc aFunc, void* aData)
{
return nsCOMArray_base::EnumerateForwards(nsBaseArrayEnumFunc(aFunc),
aData);
}
bool EnumerateBackwards(nsCOMArrayEnumFunc aFunc, void* aData)
{
return nsCOMArray_base::EnumerateBackwards(nsBaseArrayEnumFunc(aFunc),
aData);
}
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);
}
// 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));
}
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