The Tor Browser: xpcom/glue/nsCategoryCache.h@97036ab72558

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.

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

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

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

     5 #ifndef nsCategoryCache_h_

     6 #define nsCategoryCache_h_

     8 #include "mozilla/Attributes.h"

    10 #include "nsICategoryManager.h"

    11 #include "nsIObserver.h"

    12 #include "nsISimpleEnumerator.h"

    13 #include "nsISupportsPrimitives.h"

    15 #include "nsServiceManagerUtils.h"

    17 #include "nsAutoPtr.h"

    18 #include "nsCOMArray.h"

    19 #include "nsInterfaceHashtable.h"

    21 #include "nsXPCOM.h"

    23 class NS_COM_GLUE nsCategoryObserver MOZ_FINAL : public nsIObserver

    24 {

    25   public:

    26     nsCategoryObserver(const char* aCategory);

    27     ~nsCategoryObserver();

    29     void ListenerDied();

    30     nsInterfaceHashtable<nsCStringHashKey, nsISupports>& GetHash()

    31     {

    32       return mHash;

    33     }

    35     NS_DECL_ISUPPORTS

    36     NS_DECL_NSIOBSERVER

    37   private:

    38     void RemoveObservers();

    40     nsInterfaceHashtable<nsCStringHashKey, nsISupports> mHash;

    41     nsCString mCategory;

    42     bool mObserversRemoved;

    43 };

    45 /**

    46  * This is a helper class that caches services that are registered in a certain

    47  * category. The intended usage is that a service stores a variable of type

    48  * nsCategoryCache<nsIFoo> in a member variable, where nsIFoo is the interface

    49  * that these services should implement. The constructor of this class should

    50  * then get the name of the category.

    51  */

    52 template<class T>

    53 class nsCategoryCache MOZ_FINAL

    54 {

    55   public:

    56     explicit nsCategoryCache(const char* aCategory)

    57       : mCategoryName(aCategory)

    58     {

    59     }

    60     ~nsCategoryCache() {

    61       if (mObserver)

    62 	mObserver->ListenerDied();

    63     }

    65     void GetEntries(nsCOMArray<T>& result) {

    66       // Lazy initialization, so that services in this category can't

    67       // cause reentrant getService (bug 386376)

    68       if (!mObserver)

    69         mObserver = new nsCategoryObserver(mCategoryName.get());

    71       mObserver->GetHash().EnumerateRead(EntriesToArray, &result);

    72     }

    74   private:

    75     // Not to be implemented

    76     nsCategoryCache(const nsCategoryCache<T>&);

    78     static PLDHashOperator EntriesToArray(const nsACString& key,

    79 					  nsISupports* entry, void* arg)

    80     {

    81       nsCOMArray<T>& entries = *static_cast<nsCOMArray<T>*>(arg);

    83       nsCOMPtr<T> service = do_QueryInterface(entry);

    84       if (service) {

    85 	entries.AppendObject(service);

    86       }

    87       return PL_DHASH_NEXT;

    88     }

    90     nsCString mCategoryName;

    91     nsRefPtr<nsCategoryObserver> mObserver;

    93 };

    95 #endif

The Tor Browser / file revision

xpcom/glue/nsCategoryCache.h@97036ab72558

xpcom/glue/nsCategoryCache.h