michael@0: /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #include "mozilla/Attributes.h"
michael@0: 
michael@0: #include "nsEnumeratorUtils.h"
michael@0: 
michael@0: #include "nsISimpleEnumerator.h"
michael@0: #include "nsIStringEnumerator.h"
michael@0: 
michael@0: #include "nsCOMPtr.h"
michael@0: 
michael@0: class EmptyEnumeratorImpl : public nsISimpleEnumerator,
michael@0:                             public nsIUTF8StringEnumerator,
michael@0:                             public nsIStringEnumerator
michael@0: {
michael@0: public:
michael@0:     EmptyEnumeratorImpl() {}
michael@0:     // nsISupports interface
michael@0:     NS_DECL_ISUPPORTS_INHERITED  // not really inherited, but no mRefCnt
michael@0: 
michael@0:     // nsISimpleEnumerator
michael@0:     NS_DECL_NSISIMPLEENUMERATOR
michael@0:     NS_DECL_NSIUTF8STRINGENUMERATOR
michael@0:     // can't use NS_DECL_NSISTRINGENUMERATOR because they share the
michael@0:     // HasMore() signature
michael@0:     NS_IMETHOD GetNext(nsAString& aResult);
michael@0: 
michael@0:     static EmptyEnumeratorImpl* GetInstance() {
michael@0:       static const EmptyEnumeratorImpl kInstance;
michael@0:       return const_cast<EmptyEnumeratorImpl*>(&kInstance);
michael@0:     }
michael@0: };
michael@0: 
michael@0: // nsISupports interface
michael@0: NS_IMETHODIMP_(MozExternalRefCountType) EmptyEnumeratorImpl::AddRef(void)
michael@0: {
michael@0:     return 2;
michael@0: }
michael@0: 
michael@0: NS_IMETHODIMP_(MozExternalRefCountType) EmptyEnumeratorImpl::Release(void)
michael@0: {
michael@0:     return 1;
michael@0: }
michael@0: 
michael@0: NS_IMPL_QUERY_INTERFACE(EmptyEnumeratorImpl, nsISimpleEnumerator,
michael@0:                         nsIUTF8StringEnumerator, nsIStringEnumerator)
michael@0: 
michael@0: // nsISimpleEnumerator interface
michael@0: NS_IMETHODIMP EmptyEnumeratorImpl::HasMoreElements(bool* aResult)
michael@0: {
michael@0:     *aResult = false;
michael@0:     return NS_OK;
michael@0: }
michael@0: 
michael@0: NS_IMETHODIMP EmptyEnumeratorImpl::HasMore(bool* aResult)
michael@0: {
michael@0:     *aResult = false;
michael@0:     return NS_OK;
michael@0: }
michael@0: 
michael@0: NS_IMETHODIMP EmptyEnumeratorImpl::GetNext(nsISupports** aResult)
michael@0: {
michael@0:     return NS_ERROR_UNEXPECTED;
michael@0: }
michael@0: 
michael@0: NS_IMETHODIMP EmptyEnumeratorImpl::GetNext(nsACString& aResult)
michael@0: {
michael@0:     return NS_ERROR_UNEXPECTED;
michael@0: }
michael@0: 
michael@0: NS_IMETHODIMP EmptyEnumeratorImpl::GetNext(nsAString& aResult)
michael@0: {
michael@0:     return NS_ERROR_UNEXPECTED;
michael@0: }
michael@0: 
michael@0: nsresult
michael@0: NS_NewEmptyEnumerator(nsISimpleEnumerator** aResult)
michael@0: {
michael@0:     *aResult = EmptyEnumeratorImpl::GetInstance();
michael@0:     return NS_OK;
michael@0: }
michael@0: 
michael@0: ////////////////////////////////////////////////////////////////////////////////
michael@0: 
michael@0: class nsSingletonEnumerator MOZ_FINAL : public nsISimpleEnumerator
michael@0: {
michael@0: public:
michael@0:     NS_DECL_ISUPPORTS
michael@0: 
michael@0:     // nsISimpleEnumerator methods
michael@0:     NS_IMETHOD HasMoreElements(bool* aResult);
michael@0:     NS_IMETHOD GetNext(nsISupports** aResult);
michael@0: 
michael@0:     nsSingletonEnumerator(nsISupports* aValue);
michael@0: 
michael@0: private:
michael@0:     ~nsSingletonEnumerator();
michael@0: 
michael@0: protected:
michael@0:     nsISupports* mValue;
michael@0:     bool mConsumed;
michael@0: };
michael@0: 
michael@0: nsSingletonEnumerator::nsSingletonEnumerator(nsISupports* aValue)
michael@0:     : mValue(aValue)
michael@0: {
michael@0:     NS_IF_ADDREF(mValue);
michael@0:     mConsumed = (mValue ? false : true);
michael@0: }
michael@0: 
michael@0: nsSingletonEnumerator::~nsSingletonEnumerator()
michael@0: {
michael@0:     NS_IF_RELEASE(mValue);
michael@0: }
michael@0: 
michael@0: NS_IMPL_ISUPPORTS(nsSingletonEnumerator, nsISimpleEnumerator)
michael@0: 
michael@0: NS_IMETHODIMP
michael@0: nsSingletonEnumerator::HasMoreElements(bool* aResult)
michael@0: {
michael@0:     NS_PRECONDITION(aResult != 0, "null ptr");
michael@0:     if (! aResult)
michael@0:         return NS_ERROR_NULL_POINTER;
michael@0: 
michael@0:     *aResult = !mConsumed;
michael@0:     return NS_OK;
michael@0: }
michael@0: 
michael@0: 
michael@0: NS_IMETHODIMP
michael@0: nsSingletonEnumerator::GetNext(nsISupports** aResult)
michael@0: {
michael@0:     NS_PRECONDITION(aResult != 0, "null ptr");
michael@0:     if (! aResult)
michael@0:         return NS_ERROR_NULL_POINTER;
michael@0: 
michael@0:     if (mConsumed)
michael@0:         return NS_ERROR_UNEXPECTED;
michael@0: 
michael@0:     mConsumed = true;
michael@0: 
michael@0:     *aResult = mValue;
michael@0:     NS_ADDREF(*aResult);
michael@0:     return NS_OK;
michael@0: }
michael@0: 
michael@0: nsresult
michael@0: NS_NewSingletonEnumerator(nsISimpleEnumerator* *result,
michael@0:                           nsISupports* singleton)
michael@0: {
michael@0:     nsSingletonEnumerator* enumer = new nsSingletonEnumerator(singleton);
michael@0:     if (enumer == nullptr)
michael@0:         return NS_ERROR_OUT_OF_MEMORY;
michael@0:     *result = enumer; 
michael@0:     NS_ADDREF(*result);
michael@0:     return NS_OK;
michael@0: }
michael@0: 
michael@0: ////////////////////////////////////////////////////////////////////////////////
michael@0: 
michael@0: class nsUnionEnumerator MOZ_FINAL : public nsISimpleEnumerator
michael@0: {
michael@0: public:
michael@0:     NS_DECL_ISUPPORTS
michael@0: 
michael@0:     // nsISimpleEnumerator methods
michael@0:     NS_IMETHOD HasMoreElements(bool* aResult);
michael@0:     NS_IMETHOD GetNext(nsISupports** aResult);
michael@0: 
michael@0:     nsUnionEnumerator(nsISimpleEnumerator* firstEnumerator,
michael@0:                       nsISimpleEnumerator* secondEnumerator);
michael@0: 
michael@0: private:
michael@0:     ~nsUnionEnumerator();
michael@0: 
michael@0: protected:
michael@0:     nsCOMPtr<nsISimpleEnumerator> mFirstEnumerator, mSecondEnumerator;
michael@0:     bool mConsumed;
michael@0:     bool mAtSecond;
michael@0: };
michael@0: 
michael@0: nsUnionEnumerator::nsUnionEnumerator(nsISimpleEnumerator* firstEnumerator,
michael@0:                                      nsISimpleEnumerator* secondEnumerator)
michael@0:     : mFirstEnumerator(firstEnumerator),
michael@0:       mSecondEnumerator(secondEnumerator),
michael@0:       mConsumed(false), mAtSecond(false)
michael@0: {
michael@0: }
michael@0: 
michael@0: nsUnionEnumerator::~nsUnionEnumerator()
michael@0: {
michael@0: }
michael@0: 
michael@0: NS_IMPL_ISUPPORTS(nsUnionEnumerator, nsISimpleEnumerator)
michael@0: 
michael@0: NS_IMETHODIMP
michael@0: nsUnionEnumerator::HasMoreElements(bool* aResult)
michael@0: {
michael@0:     NS_PRECONDITION(aResult != 0, "null ptr");
michael@0:     if (! aResult)
michael@0:         return NS_ERROR_NULL_POINTER;
michael@0: 
michael@0:     nsresult rv;
michael@0: 
michael@0:     if (mConsumed) {
michael@0:         *aResult = false;
michael@0:         return NS_OK;
michael@0:     }
michael@0: 
michael@0:     if (! mAtSecond) {
michael@0:         rv = mFirstEnumerator->HasMoreElements(aResult);
michael@0:         if (NS_FAILED(rv)) return rv;
michael@0: 
michael@0:         if (*aResult)
michael@0:             return NS_OK;
michael@0: 
michael@0:         mAtSecond = true;
michael@0:     }
michael@0: 
michael@0:     rv = mSecondEnumerator->HasMoreElements(aResult);
michael@0:     if (NS_FAILED(rv)) return rv;
michael@0: 
michael@0:     if (*aResult)
michael@0:         return NS_OK;
michael@0: 
michael@0:     *aResult = false;
michael@0:     mConsumed = true;
michael@0:     return NS_OK;
michael@0: }
michael@0: 
michael@0: NS_IMETHODIMP
michael@0: nsUnionEnumerator::GetNext(nsISupports** aResult)
michael@0: {
michael@0:     NS_PRECONDITION(aResult != 0, "null ptr");
michael@0:     if (! aResult)
michael@0:         return NS_ERROR_NULL_POINTER;
michael@0: 
michael@0:     if (mConsumed)
michael@0:         return NS_ERROR_UNEXPECTED;
michael@0: 
michael@0:     if (! mAtSecond)
michael@0:         return mFirstEnumerator->GetNext(aResult);
michael@0: 
michael@0:     return mSecondEnumerator->GetNext(aResult);
michael@0: }
michael@0: 
michael@0: nsresult
michael@0: NS_NewUnionEnumerator(nsISimpleEnumerator* *result,
michael@0:                       nsISimpleEnumerator* firstEnumerator,
michael@0:                       nsISimpleEnumerator* secondEnumerator)
michael@0: {
michael@0:     *result = nullptr;
michael@0:     if (! firstEnumerator) {
michael@0:         *result = secondEnumerator;
michael@0:     } else if (! secondEnumerator) {
michael@0:         *result = firstEnumerator;
michael@0:     } else {
michael@0:         nsUnionEnumerator* enumer = new nsUnionEnumerator(firstEnumerator, secondEnumerator);
michael@0:         if (enumer == nullptr)
michael@0:             return NS_ERROR_OUT_OF_MEMORY;
michael@0:         *result = enumer; 
michael@0:     }
michael@0:     NS_ADDREF(*result);
michael@0:     return NS_OK;
michael@0: }