The Tor Browser: js/xpconnect/src/xpcObjectHelper.h@b8a032363ba2

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

     1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */

     2 /* vim: set ts=8 sts=4 et sw=4 tw=99: */

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

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

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

     7 #ifndef xpcObjectHelper_h

     8 #define xpcObjectHelper_h

    10 // Including 'windows.h' will #define GetClassInfo to something else.

    11 #ifdef XP_WIN

    12 #ifdef GetClassInfo

    13 #undef GetClassInfo

    14 #endif

    15 #endif

    17 #include "mozilla/Attributes.h"

    18 #include <stdint.h>

    19 #include "nsAutoPtr.h"

    20 #include "nsCOMPtr.h"

    21 #include "nsIClassInfo.h"

    22 #include "nsISupports.h"

    23 #include "nsIXPCScriptable.h"

    24 #include "nsWrapperCache.h"

    26 class xpcObjectHelper

    27 {

    28 public:

    29     xpcObjectHelper(nsISupports *aObject, nsWrapperCache *aCache = nullptr)

    30       : mCanonical(nullptr)

    31       , mObject(aObject)

    32       , mCache(aCache)

    33     {

    34         if (!mCache) {

    35             if (aObject)

    36                 CallQueryInterface(aObject, &mCache);

    37             else

    38                 mCache = nullptr;

    39         }

    40     }

    42     nsISupports *Object()

    43     {

    44         return mObject;

    45     }

    47     nsISupports *GetCanonical()

    48     {

    49         if (!mCanonical) {

    50             mCanonicalStrong = do_QueryInterface(mObject);

    51             mCanonical = mCanonicalStrong;

    52         }

    53         return mCanonical;

    54     }

    56     already_AddRefed<nsISupports> forgetCanonical()

    57     {

    58         MOZ_ASSERT(mCanonical, "Huh, no canonical to forget?");

    60         if (!mCanonicalStrong)

    61             mCanonicalStrong = mCanonical;

    62         mCanonical = nullptr;

    63         return mCanonicalStrong.forget();

    64     }

    66     nsIClassInfo *GetClassInfo()

    67     {

    68         if (mXPCClassInfo)

    69           return mXPCClassInfo;

    70         if (!mClassInfo)

    71             mClassInfo = do_QueryInterface(mObject);

    72         return mClassInfo;

    73     }

    74     nsXPCClassInfo *GetXPCClassInfo()

    75     {

    76         if (!mXPCClassInfo) {

    77             CallQueryInterface(mObject, getter_AddRefs(mXPCClassInfo));

    78         }

    79         return mXPCClassInfo;

    80     }

    82     already_AddRefed<nsXPCClassInfo> forgetXPCClassInfo()

    83     {

    84         GetXPCClassInfo();

    86         return mXPCClassInfo.forget();

    87     }

    89     // We assert that we can reach an nsIXPCScriptable somehow.

    90     uint32_t GetScriptableFlags()

    91     {

    92         // Try getting an nsXPCClassInfo - this handles DOM scriptable helpers.

    93         nsCOMPtr<nsIXPCScriptable> sinfo = GetXPCClassInfo();

    95         // If that didn't work, try just QI-ing. This handles BackstagePass.

    96         if (!sinfo)

    97             sinfo = do_QueryInterface(GetCanonical());

    99         // We should have something by now.

   100         MOZ_ASSERT(sinfo);

   102         // Grab the flags.

   103         return sinfo->GetScriptableFlags();

   104     }

   106     nsWrapperCache *GetWrapperCache()

   107     {

   108         return mCache;

   109     }

   111 protected:

   112     xpcObjectHelper(nsISupports *aObject, nsISupports *aCanonical,

   113                     nsWrapperCache *aCache)

   114       : mCanonical(aCanonical)

   115       , mObject(aObject)

   116       , mCache(aCache)

   117     {

   118         if (!mCache && aObject)

   119             CallQueryInterface(aObject, &mCache);

   120     }

   122     nsCOMPtr<nsISupports>    mCanonicalStrong;

   123     nsISupports*             mCanonical;

   125 private:

   126     xpcObjectHelper(xpcObjectHelper& aOther) MOZ_DELETE;

   128     nsISupports*             mObject;

   129     nsWrapperCache*          mCache;

   130     nsCOMPtr<nsIClassInfo>   mClassInfo;

   131     nsRefPtr<nsXPCClassInfo> mXPCClassInfo;

   132 };

   134 #endif

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