1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/xpcom/glue/nsEnumeratorUtils.cpp Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,268 @@
1.4 +/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
1.5 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.6 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.7 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.8 +
1.9 +#include "mozilla/Attributes.h"
1.10 +
1.11 +#include "nsEnumeratorUtils.h"
1.12 +
1.13 +#include "nsISimpleEnumerator.h"
1.14 +#include "nsIStringEnumerator.h"
1.15 +
1.16 +#include "nsCOMPtr.h"
1.17 +
1.18 +class EmptyEnumeratorImpl : public nsISimpleEnumerator,
1.19 + public nsIUTF8StringEnumerator,
1.20 + public nsIStringEnumerator
1.21 +{
1.22 +public:
1.23 + EmptyEnumeratorImpl() {}
1.24 + // nsISupports interface
1.25 + NS_DECL_ISUPPORTS_INHERITED // not really inherited, but no mRefCnt
1.26 +
1.27 + // nsISimpleEnumerator
1.28 + NS_DECL_NSISIMPLEENUMERATOR
1.29 + NS_DECL_NSIUTF8STRINGENUMERATOR
1.30 + // can't use NS_DECL_NSISTRINGENUMERATOR because they share the
1.31 + // HasMore() signature
1.32 + NS_IMETHOD GetNext(nsAString& aResult);
1.33 +
1.34 + static EmptyEnumeratorImpl* GetInstance() {
1.35 + static const EmptyEnumeratorImpl kInstance;
1.36 + return const_cast<EmptyEnumeratorImpl*>(&kInstance);
1.37 + }
1.38 +};
1.39 +
1.40 +// nsISupports interface
1.41 +NS_IMETHODIMP_(MozExternalRefCountType) EmptyEnumeratorImpl::AddRef(void)
1.42 +{
1.43 + return 2;
1.44 +}
1.45 +
1.46 +NS_IMETHODIMP_(MozExternalRefCountType) EmptyEnumeratorImpl::Release(void)
1.47 +{
1.48 + return 1;
1.49 +}
1.50 +
1.51 +NS_IMPL_QUERY_INTERFACE(EmptyEnumeratorImpl, nsISimpleEnumerator,
1.52 + nsIUTF8StringEnumerator, nsIStringEnumerator)
1.53 +
1.54 +// nsISimpleEnumerator interface
1.55 +NS_IMETHODIMP EmptyEnumeratorImpl::HasMoreElements(bool* aResult)
1.56 +{
1.57 + *aResult = false;
1.58 + return NS_OK;
1.59 +}
1.60 +
1.61 +NS_IMETHODIMP EmptyEnumeratorImpl::HasMore(bool* aResult)
1.62 +{
1.63 + *aResult = false;
1.64 + return NS_OK;
1.65 +}
1.66 +
1.67 +NS_IMETHODIMP EmptyEnumeratorImpl::GetNext(nsISupports** aResult)
1.68 +{
1.69 + return NS_ERROR_UNEXPECTED;
1.70 +}
1.71 +
1.72 +NS_IMETHODIMP EmptyEnumeratorImpl::GetNext(nsACString& aResult)
1.73 +{
1.74 + return NS_ERROR_UNEXPECTED;
1.75 +}
1.76 +
1.77 +NS_IMETHODIMP EmptyEnumeratorImpl::GetNext(nsAString& aResult)
1.78 +{
1.79 + return NS_ERROR_UNEXPECTED;
1.80 +}
1.81 +
1.82 +nsresult
1.83 +NS_NewEmptyEnumerator(nsISimpleEnumerator** aResult)
1.84 +{
1.85 + *aResult = EmptyEnumeratorImpl::GetInstance();
1.86 + return NS_OK;
1.87 +}
1.88 +
1.89 +////////////////////////////////////////////////////////////////////////////////
1.90 +
1.91 +class nsSingletonEnumerator MOZ_FINAL : public nsISimpleEnumerator
1.92 +{
1.93 +public:
1.94 + NS_DECL_ISUPPORTS
1.95 +
1.96 + // nsISimpleEnumerator methods
1.97 + NS_IMETHOD HasMoreElements(bool* aResult);
1.98 + NS_IMETHOD GetNext(nsISupports** aResult);
1.99 +
1.100 + nsSingletonEnumerator(nsISupports* aValue);
1.101 +
1.102 +private:
1.103 + ~nsSingletonEnumerator();
1.104 +
1.105 +protected:
1.106 + nsISupports* mValue;
1.107 + bool mConsumed;
1.108 +};
1.109 +
1.110 +nsSingletonEnumerator::nsSingletonEnumerator(nsISupports* aValue)
1.111 + : mValue(aValue)
1.112 +{
1.113 + NS_IF_ADDREF(mValue);
1.114 + mConsumed = (mValue ? false : true);
1.115 +}
1.116 +
1.117 +nsSingletonEnumerator::~nsSingletonEnumerator()
1.118 +{
1.119 + NS_IF_RELEASE(mValue);
1.120 +}
1.121 +
1.122 +NS_IMPL_ISUPPORTS(nsSingletonEnumerator, nsISimpleEnumerator)
1.123 +
1.124 +NS_IMETHODIMP
1.125 +nsSingletonEnumerator::HasMoreElements(bool* aResult)
1.126 +{
1.127 + NS_PRECONDITION(aResult != 0, "null ptr");
1.128 + if (! aResult)
1.129 + return NS_ERROR_NULL_POINTER;
1.130 +
1.131 + *aResult = !mConsumed;
1.132 + return NS_OK;
1.133 +}
1.134 +
1.135 +
1.136 +NS_IMETHODIMP
1.137 +nsSingletonEnumerator::GetNext(nsISupports** aResult)
1.138 +{
1.139 + NS_PRECONDITION(aResult != 0, "null ptr");
1.140 + if (! aResult)
1.141 + return NS_ERROR_NULL_POINTER;
1.142 +
1.143 + if (mConsumed)
1.144 + return NS_ERROR_UNEXPECTED;
1.145 +
1.146 + mConsumed = true;
1.147 +
1.148 + *aResult = mValue;
1.149 + NS_ADDREF(*aResult);
1.150 + return NS_OK;
1.151 +}
1.152 +
1.153 +nsresult
1.154 +NS_NewSingletonEnumerator(nsISimpleEnumerator* *result,
1.155 + nsISupports* singleton)
1.156 +{
1.157 + nsSingletonEnumerator* enumer = new nsSingletonEnumerator(singleton);
1.158 + if (enumer == nullptr)
1.159 + return NS_ERROR_OUT_OF_MEMORY;
1.160 + *result = enumer;
1.161 + NS_ADDREF(*result);
1.162 + return NS_OK;
1.163 +}
1.164 +
1.165 +////////////////////////////////////////////////////////////////////////////////
1.166 +
1.167 +class nsUnionEnumerator MOZ_FINAL : public nsISimpleEnumerator
1.168 +{
1.169 +public:
1.170 + NS_DECL_ISUPPORTS
1.171 +
1.172 + // nsISimpleEnumerator methods
1.173 + NS_IMETHOD HasMoreElements(bool* aResult);
1.174 + NS_IMETHOD GetNext(nsISupports** aResult);
1.175 +
1.176 + nsUnionEnumerator(nsISimpleEnumerator* firstEnumerator,
1.177 + nsISimpleEnumerator* secondEnumerator);
1.178 +
1.179 +private:
1.180 + ~nsUnionEnumerator();
1.181 +
1.182 +protected:
1.183 + nsCOMPtr<nsISimpleEnumerator> mFirstEnumerator, mSecondEnumerator;
1.184 + bool mConsumed;
1.185 + bool mAtSecond;
1.186 +};
1.187 +
1.188 +nsUnionEnumerator::nsUnionEnumerator(nsISimpleEnumerator* firstEnumerator,
1.189 + nsISimpleEnumerator* secondEnumerator)
1.190 + : mFirstEnumerator(firstEnumerator),
1.191 + mSecondEnumerator(secondEnumerator),
1.192 + mConsumed(false), mAtSecond(false)
1.193 +{
1.194 +}
1.195 +
1.196 +nsUnionEnumerator::~nsUnionEnumerator()
1.197 +{
1.198 +}
1.199 +
1.200 +NS_IMPL_ISUPPORTS(nsUnionEnumerator, nsISimpleEnumerator)
1.201 +
1.202 +NS_IMETHODIMP
1.203 +nsUnionEnumerator::HasMoreElements(bool* aResult)
1.204 +{
1.205 + NS_PRECONDITION(aResult != 0, "null ptr");
1.206 + if (! aResult)
1.207 + return NS_ERROR_NULL_POINTER;
1.208 +
1.209 + nsresult rv;
1.210 +
1.211 + if (mConsumed) {
1.212 + *aResult = false;
1.213 + return NS_OK;
1.214 + }
1.215 +
1.216 + if (! mAtSecond) {
1.217 + rv = mFirstEnumerator->HasMoreElements(aResult);
1.218 + if (NS_FAILED(rv)) return rv;
1.219 +
1.220 + if (*aResult)
1.221 + return NS_OK;
1.222 +
1.223 + mAtSecond = true;
1.224 + }
1.225 +
1.226 + rv = mSecondEnumerator->HasMoreElements(aResult);
1.227 + if (NS_FAILED(rv)) return rv;
1.228 +
1.229 + if (*aResult)
1.230 + return NS_OK;
1.231 +
1.232 + *aResult = false;
1.233 + mConsumed = true;
1.234 + return NS_OK;
1.235 +}
1.236 +
1.237 +NS_IMETHODIMP
1.238 +nsUnionEnumerator::GetNext(nsISupports** aResult)
1.239 +{
1.240 + NS_PRECONDITION(aResult != 0, "null ptr");
1.241 + if (! aResult)
1.242 + return NS_ERROR_NULL_POINTER;
1.243 +
1.244 + if (mConsumed)
1.245 + return NS_ERROR_UNEXPECTED;
1.246 +
1.247 + if (! mAtSecond)
1.248 + return mFirstEnumerator->GetNext(aResult);
1.249 +
1.250 + return mSecondEnumerator->GetNext(aResult);
1.251 +}
1.252 +
1.253 +nsresult
1.254 +NS_NewUnionEnumerator(nsISimpleEnumerator* *result,
1.255 + nsISimpleEnumerator* firstEnumerator,
1.256 + nsISimpleEnumerator* secondEnumerator)
1.257 +{
1.258 + *result = nullptr;
1.259 + if (! firstEnumerator) {
1.260 + *result = secondEnumerator;
1.261 + } else if (! secondEnumerator) {
1.262 + *result = firstEnumerator;
1.263 + } else {
1.264 + nsUnionEnumerator* enumer = new nsUnionEnumerator(firstEnumerator, secondEnumerator);
1.265 + if (enumer == nullptr)
1.266 + return NS_ERROR_OUT_OF_MEMORY;
1.267 + *result = enumer;
1.268 + }
1.269 + NS_ADDREF(*result);
1.270 + return NS_OK;
1.271 +}
