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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/. */
#include "mozilla/Attributes.h"
#include "nsArrayEnumerator.h"
#include "nsIArray.h"
#include "nsSimpleEnumerator.h"
#include "nsCOMArray.h"
#include "nsCOMPtr.h"
#include "mozilla/OperatorNewExtensions.h"
#include "mozilla/RefPtr.h"
class nsSimpleArrayEnumerator final : public nsSimpleEnumerator {
public:
// nsISimpleEnumerator interface
NS_DECL_NSISIMPLEENUMERATOR
// nsSimpleArrayEnumerator methods
explicit nsSimpleArrayEnumerator(nsIArray* aValueArray, const nsID& aEntryIID)
: mValueArray(aValueArray), mEntryIID(aEntryIID), mIndex(0) {}
const nsID& DefaultInterface() override { return mEntryIID; }
private:
~nsSimpleArrayEnumerator() override = default;
protected:
nsCOMPtr<nsIArray> mValueArray;
const nsID mEntryIID;
uint32_t mIndex;
};
NS_IMETHODIMP
nsSimpleArrayEnumerator::HasMoreElements(bool* aResult) {
MOZ_ASSERT(aResult != 0, "null ptr");
if (!aResult) {
return NS_ERROR_NULL_POINTER;
}
if (!mValueArray) {
*aResult = false;
return NS_OK;
}
uint32_t cnt;
nsresult rv = mValueArray->GetLength(&cnt);
if (NS_FAILED(rv)) {
return rv;
}
*aResult = (mIndex < cnt);
return NS_OK;
}
NS_IMETHODIMP
nsSimpleArrayEnumerator::GetNext(nsISupports** aResult) {
MOZ_ASSERT(aResult != 0, "null ptr");
if (!aResult) {
return NS_ERROR_NULL_POINTER;
}
if (!mValueArray) {
*aResult = nullptr;
return NS_OK;
}
uint32_t cnt;
nsresult rv = mValueArray->GetLength(&cnt);
if (NS_FAILED(rv)) {
return rv;
}
if (mIndex >= cnt) {
return NS_ERROR_UNEXPECTED;
}
return mValueArray->QueryElementAt(mIndex++, NS_GET_IID(nsISupports),
(void**)aResult);
}
nsresult NS_NewArrayEnumerator(nsISimpleEnumerator** aResult, nsIArray* aArray,
const nsID& aEntryIID) {
RefPtr<nsSimpleArrayEnumerator> enumer =
new nsSimpleArrayEnumerator(aArray, aEntryIID);
enumer.forget(aResult);
return NS_OK;
}
////////////////////////////////////////////////////////////////////////////////
// enumerator implementation for nsCOMArray
// creates a snapshot of the array in question
// you MUST use NS_NewArrayEnumerator to create this, so that
// allocation is done correctly
class nsCOMArrayEnumerator final : public nsSimpleEnumerator {
public:
// nsISimpleEnumerator interface
NS_DECL_NSISIMPLEENUMERATOR
// Use this instead of `new`.
static nsCOMArrayEnumerator* Allocate(const nsCOMArray_base& aArray,
const nsID& aEntryIID);
// specialized operator to make sure we make room for mValues
void operator delete(void* aPtr) { free(aPtr); }
const nsID& DefaultInterface() override { return mEntryIID; }
private:
// nsSimpleArrayEnumerator methods
explicit nsCOMArrayEnumerator(const nsID& aEntryIID)
: mIndex(0), mArraySize(0), mEntryIID(aEntryIID) {
mValueArray[0] = nullptr;
}
~nsCOMArrayEnumerator(void) override;
protected:
uint32_t mIndex; // current position
uint32_t mArraySize; // size of the array
const nsID& mEntryIID;
// this is actually bigger
nsISupports* mValueArray[1];
};
nsCOMArrayEnumerator::~nsCOMArrayEnumerator() {
// only release the entries that we haven't visited yet
for (; mIndex < mArraySize; ++mIndex) {
NS_IF_RELEASE(mValueArray[mIndex]);
}
}
NS_IMETHODIMP
nsCOMArrayEnumerator::HasMoreElements(bool* aResult) {
MOZ_ASSERT(aResult != 0, "null ptr");
if (!aResult) {
return NS_ERROR_NULL_POINTER;
}
*aResult = (mIndex < mArraySize);
return NS_OK;
}
NS_IMETHODIMP
nsCOMArrayEnumerator::GetNext(nsISupports** aResult) {
MOZ_ASSERT(aResult != 0, "null ptr");
if (!aResult) {
return NS_ERROR_NULL_POINTER;
}
if (mIndex >= mArraySize) {
return NS_ERROR_UNEXPECTED;
}
// pass the ownership of the reference to the caller. Since
// we AddRef'ed during creation of |this|, there is no need
// to AddRef here
*aResult = mValueArray[mIndex++];
// this really isn't necessary. just pretend this happens, since
// we'll never visit this value again!
// mValueArray[(mIndex-1)] = nullptr;
return NS_OK;
}
nsCOMArrayEnumerator* nsCOMArrayEnumerator::Allocate(
const nsCOMArray_base& aArray, const nsID& aEntryIID) {
// create enough space such that mValueArray points to a large
// enough value. Note that the initial value of aSize gives us
// space for mValueArray[0], so we must subtract
size_t size = sizeof(nsCOMArrayEnumerator);
uint32_t count;
if (aArray.Count() > 0) {
count = static_cast<uint32_t>(aArray.Count());
size += (count - 1) * sizeof(aArray[0]);
} else {
count = 0;
}
// Allocate a buffer large enough to contain our object and its array.
void* mem = moz_xmalloc(size);
auto result =
new (mozilla::KnownNotNull, mem) nsCOMArrayEnumerator(aEntryIID);
result->mArraySize = count;
// now need to copy over the values, and addref each one
// now this might seem like a lot of work, but we're actually just
// doing all our AddRef's ahead of time since GetNext() doesn't
// need to AddRef() on the way out
for (uint32_t i = 0; i < count; ++i) {
result->mValueArray[i] = aArray[i];
NS_IF_ADDREF(result->mValueArray[i]);
}
return result;
}
nsresult NS_NewArrayEnumerator(nsISimpleEnumerator** aResult,
const nsCOMArray_base& aArray,
const nsID& aEntryIID) {
RefPtr<nsCOMArrayEnumerator> enumerator =
nsCOMArrayEnumerator::Allocate(aArray, aEntryIID);
enumerator.forget(aResult);
return NS_OK;
}