The Tor Browser: xpcom/glue/nsEnumeratorUtils.cpp@b8a032363ba2

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

     1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */

     2 /* This Source Code Form is subject to the terms of the Mozilla Public

     3  * License, v. 2.0. If a copy of the MPL was not distributed with this

     4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

     6 #include "mozilla/Attributes.h"

     8 #include "nsEnumeratorUtils.h"

    10 #include "nsISimpleEnumerator.h"

    11 #include "nsIStringEnumerator.h"

    13 #include "nsCOMPtr.h"

    15 class EmptyEnumeratorImpl : public nsISimpleEnumerator,

    16                             public nsIUTF8StringEnumerator,

    17                             public nsIStringEnumerator

    18 {

    19 public:

    20     EmptyEnumeratorImpl() {}

    21     // nsISupports interface

    22     NS_DECL_ISUPPORTS_INHERITED  // not really inherited, but no mRefCnt

    24     // nsISimpleEnumerator

    25     NS_DECL_NSISIMPLEENUMERATOR

    26     NS_DECL_NSIUTF8STRINGENUMERATOR

    27     // can't use NS_DECL_NSISTRINGENUMERATOR because they share the

    28     // HasMore() signature

    29     NS_IMETHOD GetNext(nsAString& aResult);

    31     static EmptyEnumeratorImpl* GetInstance() {

    32       static const EmptyEnumeratorImpl kInstance;

    33       return const_cast<EmptyEnumeratorImpl*>(&kInstance);

    34     }

    35 };

    37 // nsISupports interface

    38 NS_IMETHODIMP_(MozExternalRefCountType) EmptyEnumeratorImpl::AddRef(void)

    39 {

    40     return 2;

    41 }

    43 NS_IMETHODIMP_(MozExternalRefCountType) EmptyEnumeratorImpl::Release(void)

    44 {

    45     return 1;

    46 }

    48 NS_IMPL_QUERY_INTERFACE(EmptyEnumeratorImpl, nsISimpleEnumerator,

    49                         nsIUTF8StringEnumerator, nsIStringEnumerator)

    51 // nsISimpleEnumerator interface

    52 NS_IMETHODIMP EmptyEnumeratorImpl::HasMoreElements(bool* aResult)

    53 {

    54     *aResult = false;

    55     return NS_OK;

    56 }

    58 NS_IMETHODIMP EmptyEnumeratorImpl::HasMore(bool* aResult)

    59 {

    60     *aResult = false;

    61     return NS_OK;

    62 }

    64 NS_IMETHODIMP EmptyEnumeratorImpl::GetNext(nsISupports** aResult)

    65 {

    66     return NS_ERROR_UNEXPECTED;

    67 }

    69 NS_IMETHODIMP EmptyEnumeratorImpl::GetNext(nsACString& aResult)

    70 {

    71     return NS_ERROR_UNEXPECTED;

    72 }

    74 NS_IMETHODIMP EmptyEnumeratorImpl::GetNext(nsAString& aResult)

    75 {

    76     return NS_ERROR_UNEXPECTED;

    77 }

    79 nsresult

    80 NS_NewEmptyEnumerator(nsISimpleEnumerator** aResult)

    81 {

    82     *aResult = EmptyEnumeratorImpl::GetInstance();

    83     return NS_OK;

    84 }

    86 ////////////////////////////////////////////////////////////////////////////////

    88 class nsSingletonEnumerator MOZ_FINAL : public nsISimpleEnumerator

    89 {

    90 public:

    91     NS_DECL_ISUPPORTS

    93     // nsISimpleEnumerator methods

    94     NS_IMETHOD HasMoreElements(bool* aResult);

    95     NS_IMETHOD GetNext(nsISupports** aResult);

    97     nsSingletonEnumerator(nsISupports* aValue);

    99 private:

   100     ~nsSingletonEnumerator();

   102 protected:

   103     nsISupports* mValue;

   104     bool mConsumed;

   105 };

   107 nsSingletonEnumerator::nsSingletonEnumerator(nsISupports* aValue)

   108     : mValue(aValue)

   109 {

   110     NS_IF_ADDREF(mValue);

   111     mConsumed = (mValue ? false : true);

   112 }

   114 nsSingletonEnumerator::~nsSingletonEnumerator()

   115 {

   116     NS_IF_RELEASE(mValue);

   117 }

   119 NS_IMPL_ISUPPORTS(nsSingletonEnumerator, nsISimpleEnumerator)

   121 NS_IMETHODIMP

   122 nsSingletonEnumerator::HasMoreElements(bool* aResult)

   123 {

   124     NS_PRECONDITION(aResult != 0, "null ptr");

   125     if (! aResult)

   126         return NS_ERROR_NULL_POINTER;

   128     *aResult = !mConsumed;

   129     return NS_OK;

   130 }

   133 NS_IMETHODIMP

   134 nsSingletonEnumerator::GetNext(nsISupports** aResult)

   135 {

   136     NS_PRECONDITION(aResult != 0, "null ptr");

   137     if (! aResult)

   138         return NS_ERROR_NULL_POINTER;

   140     if (mConsumed)

   141         return NS_ERROR_UNEXPECTED;

   143     mConsumed = true;

   145     *aResult = mValue;

   146     NS_ADDREF(*aResult);

   147     return NS_OK;

   148 }

   150 nsresult

   151 NS_NewSingletonEnumerator(nsISimpleEnumerator* *result,

   152                           nsISupports* singleton)

   153 {

   154     nsSingletonEnumerator* enumer = new nsSingletonEnumerator(singleton);

   155     if (enumer == nullptr)

   156         return NS_ERROR_OUT_OF_MEMORY;

   157     *result = enumer;

   158     NS_ADDREF(*result);

   159     return NS_OK;

   160 }

   162 ////////////////////////////////////////////////////////////////////////////////

   164 class nsUnionEnumerator MOZ_FINAL : public nsISimpleEnumerator

   165 {

   166 public:

   167     NS_DECL_ISUPPORTS

   169     // nsISimpleEnumerator methods

   170     NS_IMETHOD HasMoreElements(bool* aResult);

   171     NS_IMETHOD GetNext(nsISupports** aResult);

   173     nsUnionEnumerator(nsISimpleEnumerator* firstEnumerator,

   174                       nsISimpleEnumerator* secondEnumerator);

   176 private:

   177     ~nsUnionEnumerator();

   179 protected:

   180     nsCOMPtr<nsISimpleEnumerator> mFirstEnumerator, mSecondEnumerator;

   181     bool mConsumed;

   182     bool mAtSecond;

   183 };

   185 nsUnionEnumerator::nsUnionEnumerator(nsISimpleEnumerator* firstEnumerator,

   186                                      nsISimpleEnumerator* secondEnumerator)

   187     : mFirstEnumerator(firstEnumerator),

   188       mSecondEnumerator(secondEnumerator),

   189       mConsumed(false), mAtSecond(false)

   190 {

   191 }

   193 nsUnionEnumerator::~nsUnionEnumerator()

   194 {

   195 }

   197 NS_IMPL_ISUPPORTS(nsUnionEnumerator, nsISimpleEnumerator)

   199 NS_IMETHODIMP

   200 nsUnionEnumerator::HasMoreElements(bool* aResult)

   201 {

   202     NS_PRECONDITION(aResult != 0, "null ptr");

   203     if (! aResult)

   204         return NS_ERROR_NULL_POINTER;

   206     nsresult rv;

   208     if (mConsumed) {

   209         *aResult = false;

   210         return NS_OK;

   211     }

   213     if (! mAtSecond) {

   214         rv = mFirstEnumerator->HasMoreElements(aResult);

   215         if (NS_FAILED(rv)) return rv;

   217         if (*aResult)

   218             return NS_OK;

   220         mAtSecond = true;

   221     }

   223     rv = mSecondEnumerator->HasMoreElements(aResult);

   224     if (NS_FAILED(rv)) return rv;

   226     if (*aResult)

   227         return NS_OK;

   229     *aResult = false;

   230     mConsumed = true;

   231     return NS_OK;

   232 }

   234 NS_IMETHODIMP

   235 nsUnionEnumerator::GetNext(nsISupports** aResult)

   236 {

   237     NS_PRECONDITION(aResult != 0, "null ptr");

   238     if (! aResult)

   239         return NS_ERROR_NULL_POINTER;

   241     if (mConsumed)

   242         return NS_ERROR_UNEXPECTED;

   244     if (! mAtSecond)

   245         return mFirstEnumerator->GetNext(aResult);

   247     return mSecondEnumerator->GetNext(aResult);

   248 }

   250 nsresult

   251 NS_NewUnionEnumerator(nsISimpleEnumerator* *result,

   252                       nsISimpleEnumerator* firstEnumerator,

   253                       nsISimpleEnumerator* secondEnumerator)

   254 {

   255     *result = nullptr;

   256     if (! firstEnumerator) {

   257         *result = secondEnumerator;

   258     } else if (! secondEnumerator) {

   259         *result = firstEnumerator;

   260     } else {

   261         nsUnionEnumerator* enumer = new nsUnionEnumerator(firstEnumerator, secondEnumerator);

   262         if (enumer == nullptr)

   263             return NS_ERROR_OUT_OF_MEMORY;

   264         *result = enumer;

   265     }

   266     NS_ADDREF(*result);

   267     return NS_OK;

   268 }

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