gecko-dev/xpcom/glue/nsEnumeratorUtils.cpp

288 строки
6.1 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/. */
#include "mozilla/Attributes.h"
#include "nsEnumeratorUtils.h"
#include "nsISimpleEnumerator.h"
#include "nsIStringEnumerator.h"
#include "nsCOMPtr.h"
#include "mozilla/RefPtr.h"
class EmptyEnumeratorImpl
: public nsISimpleEnumerator
, public nsIUTF8StringEnumerator
, public nsIStringEnumerator
{
public:
EmptyEnumeratorImpl() {}
// nsISupports interface
NS_DECL_ISUPPORTS_INHERITED // not really inherited, but no mRefCnt
// nsISimpleEnumerator
NS_DECL_NSISIMPLEENUMERATOR
NS_DECL_NSIUTF8STRINGENUMERATOR
// can't use NS_DECL_NSISTRINGENUMERATOR because they share the
// HasMore() signature
NS_IMETHOD GetNext(nsAString& aResult) override;
static EmptyEnumeratorImpl* GetInstance()
{
static const EmptyEnumeratorImpl kInstance;
return const_cast<EmptyEnumeratorImpl*>(&kInstance);
}
};
// nsISupports interface
NS_IMETHODIMP_(MozExternalRefCountType)
EmptyEnumeratorImpl::AddRef(void)
{
return 2;
}
NS_IMETHODIMP_(MozExternalRefCountType)
EmptyEnumeratorImpl::Release(void)
{
return 1;
}
NS_IMPL_QUERY_INTERFACE(EmptyEnumeratorImpl, nsISimpleEnumerator,
nsIUTF8StringEnumerator, nsIStringEnumerator)
// nsISimpleEnumerator interface
NS_IMETHODIMP
EmptyEnumeratorImpl::HasMoreElements(bool* aResult)
{
*aResult = false;
return NS_OK;
}
NS_IMETHODIMP
EmptyEnumeratorImpl::HasMore(bool* aResult)
{
*aResult = false;
return NS_OK;
}
NS_IMETHODIMP
EmptyEnumeratorImpl::GetNext(nsISupports** aResult)
{
return NS_ERROR_UNEXPECTED;
}
NS_IMETHODIMP
EmptyEnumeratorImpl::GetNext(nsACString& aResult)
{
return NS_ERROR_UNEXPECTED;
}
NS_IMETHODIMP
EmptyEnumeratorImpl::GetNext(nsAString& aResult)
{
return NS_ERROR_UNEXPECTED;
}
nsresult
NS_NewEmptyEnumerator(nsISimpleEnumerator** aResult)
{
*aResult = EmptyEnumeratorImpl::GetInstance();
return NS_OK;
}
////////////////////////////////////////////////////////////////////////////////
class nsSingletonEnumerator final : public nsISimpleEnumerator
{
public:
NS_DECL_ISUPPORTS
// nsISimpleEnumerator methods
NS_IMETHOD HasMoreElements(bool* aResult) override;
NS_IMETHOD GetNext(nsISupports** aResult) override;
explicit nsSingletonEnumerator(nsISupports* aValue);
private:
~nsSingletonEnumerator();
protected:
nsCOMPtr<nsISupports> mValue;
bool mConsumed;
};
nsSingletonEnumerator::nsSingletonEnumerator(nsISupports* aValue)
: mValue(aValue)
{
mConsumed = (mValue ? false : true);
}
nsSingletonEnumerator::~nsSingletonEnumerator() = default;
NS_IMPL_ISUPPORTS(nsSingletonEnumerator, nsISimpleEnumerator)
NS_IMETHODIMP
nsSingletonEnumerator::HasMoreElements(bool* aResult)
{
NS_PRECONDITION(aResult != 0, "null ptr");
if (!aResult) {
return NS_ERROR_NULL_POINTER;
}
*aResult = !mConsumed;
return NS_OK;
}
NS_IMETHODIMP
nsSingletonEnumerator::GetNext(nsISupports** aResult)
{
NS_PRECONDITION(aResult != 0, "null ptr");
if (!aResult) {
return NS_ERROR_NULL_POINTER;
}
if (mConsumed) {
return NS_ERROR_UNEXPECTED;
}
mConsumed = true;
*aResult = mValue;
NS_ADDREF(*aResult);
return NS_OK;
}
nsresult
NS_NewSingletonEnumerator(nsISimpleEnumerator** aResult,
nsISupports* aSingleton)
{
RefPtr<nsSingletonEnumerator> enumer = new nsSingletonEnumerator(aSingleton);
enumer.forget(aResult);
return NS_OK;
}
////////////////////////////////////////////////////////////////////////////////
class nsUnionEnumerator final : public nsISimpleEnumerator
{
public:
NS_DECL_ISUPPORTS
// nsISimpleEnumerator methods
NS_IMETHOD HasMoreElements(bool* aResult) override;
NS_IMETHOD GetNext(nsISupports** aResult) override;
nsUnionEnumerator(nsISimpleEnumerator* aFirstEnumerator,
nsISimpleEnumerator* aSecondEnumerator);
private:
~nsUnionEnumerator();
protected:
nsCOMPtr<nsISimpleEnumerator> mFirstEnumerator, mSecondEnumerator;
bool mConsumed;
bool mAtSecond;
};
nsUnionEnumerator::nsUnionEnumerator(nsISimpleEnumerator* aFirstEnumerator,
nsISimpleEnumerator* aSecondEnumerator)
: mFirstEnumerator(aFirstEnumerator)
, mSecondEnumerator(aSecondEnumerator)
, mConsumed(false)
, mAtSecond(false)
{
}
nsUnionEnumerator::~nsUnionEnumerator() = default;
NS_IMPL_ISUPPORTS(nsUnionEnumerator, nsISimpleEnumerator)
NS_IMETHODIMP
nsUnionEnumerator::HasMoreElements(bool* aResult)
{
NS_PRECONDITION(aResult != 0, "null ptr");
if (!aResult) {
return NS_ERROR_NULL_POINTER;
}
nsresult rv;
if (mConsumed) {
*aResult = false;
return NS_OK;
}
if (!mAtSecond) {
rv = mFirstEnumerator->HasMoreElements(aResult);
if (NS_FAILED(rv)) {
return rv;
}
if (*aResult) {
return NS_OK;
}
mAtSecond = true;
}
rv = mSecondEnumerator->HasMoreElements(aResult);
if (NS_FAILED(rv)) {
return rv;
}
if (*aResult) {
return NS_OK;
}
*aResult = false;
mConsumed = true;
return NS_OK;
}
NS_IMETHODIMP
nsUnionEnumerator::GetNext(nsISupports** aResult)
{
NS_PRECONDITION(aResult != 0, "null ptr");
if (!aResult) {
return NS_ERROR_NULL_POINTER;
}
if (mConsumed) {
return NS_ERROR_UNEXPECTED;
}
if (!mAtSecond) {
return mFirstEnumerator->GetNext(aResult);
}
return mSecondEnumerator->GetNext(aResult);
}
nsresult
NS_NewUnionEnumerator(nsISimpleEnumerator** aResult,
nsISimpleEnumerator* aFirstEnumerator,
nsISimpleEnumerator* aSecondEnumerator)
{
*aResult = nullptr;
if (!aFirstEnumerator) {
*aResult = aSecondEnumerator;
} else if (!aSecondEnumerator) {
*aResult = aFirstEnumerator;
} else {
auto* enumer = new nsUnionEnumerator(aFirstEnumerator,
aSecondEnumerator);
if (!enumer) {
return NS_ERROR_OUT_OF_MEMORY;
}
*aResult = enumer;
}
NS_ADDREF(*aResult);
return NS_OK;
}