The Tor Browser: xpcom/glue/nsEnumeratorUtils.cpp@97036ab72558 (annotated)

xpcom/glue/nsEnumeratorUtils.cpp@97036ab72558 (annotated)

xpcom/glue/nsEnumeratorUtils.cpp

Tue, 06 Jan 2015 21:39:09 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Tue, 06 Jan 2015 21:39:09 +0100
branch: TOR_BUG_9701
changeset 8: 97036ab72558
permissions: -rw-r--r--

Conditionally force memory storage according to privacy.thirdparty.isolate;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.

 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
 /* 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"
 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);
     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 MOZ_FINAL : public nsISimpleEnumerator
 {
 public:
     NS_DECL_ISUPPORTS
     // nsISimpleEnumerator methods
     NS_IMETHOD HasMoreElements(bool* aResult);
     NS_IMETHOD GetNext(nsISupports** aResult);
     nsSingletonEnumerator(nsISupports* aValue);
 private:
     ~nsSingletonEnumerator();
 protected:
     nsISupports* mValue;
     bool mConsumed;
 };
 nsSingletonEnumerator::nsSingletonEnumerator(nsISupports* aValue)
     : mValue(aValue)
 {
     NS_IF_ADDREF(mValue);
     mConsumed = (mValue ? false : true);
 }
 nsSingletonEnumerator::~nsSingletonEnumerator()
 {
     NS_IF_RELEASE(mValue);
 }
 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* *result,
                           nsISupports* singleton)
 {
     nsSingletonEnumerator* enumer = new nsSingletonEnumerator(singleton);
     if (enumer == nullptr)
         return NS_ERROR_OUT_OF_MEMORY;
     *result = enumer;
     NS_ADDREF(*result);
     return NS_OK;
 }
 ////////////////////////////////////////////////////////////////////////////////
 class nsUnionEnumerator MOZ_FINAL : public nsISimpleEnumerator
 {
 public:
     NS_DECL_ISUPPORTS
     // nsISimpleEnumerator methods
     NS_IMETHOD HasMoreElements(bool* aResult);
     NS_IMETHOD GetNext(nsISupports** aResult);
     nsUnionEnumerator(nsISimpleEnumerator* firstEnumerator,
                       nsISimpleEnumerator* secondEnumerator);
 private:
     ~nsUnionEnumerator();
 protected:
     nsCOMPtr<nsISimpleEnumerator> mFirstEnumerator, mSecondEnumerator;
     bool mConsumed;
     bool mAtSecond;
 };
 nsUnionEnumerator::nsUnionEnumerator(nsISimpleEnumerator* firstEnumerator,
                                      nsISimpleEnumerator* secondEnumerator)
     : mFirstEnumerator(firstEnumerator),
       mSecondEnumerator(secondEnumerator),
       mConsumed(false), mAtSecond(false)
 {
 }
 nsUnionEnumerator::~nsUnionEnumerator()
 {
 }
 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* *result,
                       nsISimpleEnumerator* firstEnumerator,
                       nsISimpleEnumerator* secondEnumerator)
 {
     *result = nullptr;
     if (! firstEnumerator) {
         *result = secondEnumerator;
     } else if (! secondEnumerator) {
         *result = firstEnumerator;
     } else {
         nsUnionEnumerator* enumer = new nsUnionEnumerator(firstEnumerator, secondEnumerator);
         if (enumer == nullptr)
             return NS_ERROR_OUT_OF_MEMORY;
         *result = enumer;
     }
     NS_ADDREF(*result);
     return NS_OK;
 }

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xpcom/glue/nsEnumeratorUtils.cpp@97036ab72558 (annotated)

xpcom/glue/nsEnumeratorUtils.cpp