The Tor Browser: layout/generic/nsQueryFrame.h@6474c204b198

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

     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 nsQueryFrame_h

     6 #define nsQueryFrame_h

     8 #include "nscore.h"

     9 #include "mozilla/Assertions.h"

    10 #include "mozilla/TypeTraits.h"

    12 // NOTE: the long lines in this file are intentional to make compiler error

    13 // messages more readable.

    15 #define NS_DECL_QUERYFRAME_TARGET(classname)                    \

    16   static const nsQueryFrame::FrameIID kFrameIID = nsQueryFrame::classname##_id; \

    17   typedef classname Has_NS_DECL_QUERYFRAME_TARGET;

    19 #define NS_DECL_QUERYFRAME                                      \

    20   virtual void* QueryFrame(FrameIID id);

    22 #define NS_QUERYFRAME_HEAD(class)                               \

    23   void* class::QueryFrame(FrameIID id) { switch (id) {

    25 #define NS_QUERYFRAME_ENTRY(class)                              \

    26   case class::kFrameIID: {                                      \

    27     static_assert(mozilla::IsSame<class, class::Has_NS_DECL_QUERYFRAME_TARGET>::value, \

    28                   #class " must declare itself as a queryframe target"); \

    29     return static_cast<class*>(this);                           \

    30   }

    32 #define NS_QUERYFRAME_ENTRY_CONDITIONAL(class, condition)       \

    33   case class::kFrameIID:                                        \

    34   if (condition) {                                              \

    35     static_assert(mozilla::IsSame<class, class::Has_NS_DECL_QUERYFRAME_TARGET>::value, \

    36                   #class " must declare itself as a queryframe target"); \

    37     return static_cast<class*>(this);                           \

    38   }                                                             \

    39   break;

    41 #define NS_QUERYFRAME_TAIL_INHERITING(class)                    \

    42   default: break;                                               \

    43   }                                                             \

    44   return class::QueryFrame(id);                                 \

    45 }

    47 #define NS_QUERYFRAME_TAIL_INHERITANCE_ROOT                     \

    48   default: break;                                               \

    49   }                                                             \

    50   MOZ_ASSERT(id != GetFrameId(),                                \

    51     "A frame failed to QueryFrame to its *own type*. "          \

    52     "It may be missing NS_DECL_QUERYFRAME, or a "               \

    53     "NS_QUERYFRAME_ENTRY() line with its own type name");       \

    54   return nullptr;                                               \

    55 }

    57 class nsQueryFrame

    58 {

    59 public:

    60   enum FrameIID {

    61 #define FRAME_ID(classname) classname##_id,

    62 #include "nsFrameIdList.h"

    63 #undef FRAME_ID

    65     // The PresArena implementation uses this bit to distinguish objects

    66     // allocated by size from objects allocated by type ID (that is, frames

    67     // using AllocateByFrameID, and other objects using AllocateByObjectID).

    68     // It should not collide with any frame ID (above) or Object ID (in

    69     // nsPresArena.h).  It is not 0x80000000 to avoid the question of

    70     // whether enumeration constants are signed.

    71     NON_FRAME_MARKER = 0x20000000

    72   };

    74   virtual void* QueryFrame(FrameIID id) = 0;

    75 };

    77 class do_QueryFrame

    78 {

    79 public:

    80   do_QueryFrame(nsQueryFrame *s) : mRawPtr(s) { }

    82   template<class Dest>

    83   operator Dest*() {

    84     static_assert(mozilla::IsSame<Dest, typename Dest::Has_NS_DECL_QUERYFRAME_TARGET>::value,

    85                   "Dest must declare itself as a queryframe target");

    86     if (!mRawPtr)

    87       return nullptr;

    89     return reinterpret_cast<Dest*>(mRawPtr->QueryFrame(Dest::kFrameIID));

    90   }

    92 private:

    93   nsQueryFrame *mRawPtr;

    94 };

    96 #endif // nsQueryFrame_h

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