Line data    Source code

       1             : /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
       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/. */
       5             : 
       6             : /**
       7             :  * LookupResult is the return type of SurfaceCache's Lookup*() functions. It
       8             :  * combines a surface with relevant metadata tracked by SurfaceCache.
       9             :  */
      10             : 
      11             : #ifndef mozilla_image_LookupResult_h
      12             : #define mozilla_image_LookupResult_h
      13             : 
      14             : #include "mozilla/Attributes.h"
      15             : #include "mozilla/Move.h"
      16             : #include "ISurfaceProvider.h"
      17             : 
      18             : namespace mozilla {
      19             : namespace image {
      20             : 
      21             : enum class MatchType : uint8_t
      22             : {
      23             :   NOT_FOUND,  // No matching surface and no placeholder.
      24             :   PENDING,    // Found a matching placeholder, but no surface.
      25             :   EXACT,      // Found a surface that matches exactly.
      26             :   SUBSTITUTE_BECAUSE_NOT_FOUND,  // No exact match, but found a similar one.
      27             :   SUBSTITUTE_BECAUSE_PENDING     // Found a similar surface and a placeholder
      28             :                                  // for an exact match.
      29             : };
      30             : 
      31             : /**
      32             :  * LookupResult is the return type of SurfaceCache's Lookup*() functions. It
      33             :  * combines a surface with relevant metadata tracked by SurfaceCache.
      34             :  */
      35         206 : class MOZ_STACK_CLASS LookupResult
      36             : {
      37             : public:
      38          80 :   explicit LookupResult(MatchType aMatchType)
      39          80 :     : mMatchType(aMatchType)
      40             :   {
      41          80 :     MOZ_ASSERT(mMatchType == MatchType::NOT_FOUND ||
      42             :                mMatchType == MatchType::PENDING,
      43             :                "Only NOT_FOUND or PENDING make sense with no surface");
      44          80 :   }
      45             : 
      46           5 :   LookupResult(LookupResult&& aOther)
      47           5 :     : mSurface(Move(aOther.mSurface))
      48           5 :     , mMatchType(aOther.mMatchType)
      49           5 :   { }
      50             : 
      51         121 :   LookupResult(DrawableSurface&& aSurface, MatchType aMatchType)
      52         121 :     : mSurface(Move(aSurface))
      53         121 :     , mMatchType(aMatchType)
      54             :   {
      55         121 :     MOZ_ASSERT(!mSurface || !(mMatchType == MatchType::NOT_FOUND ||
      56             :                               mMatchType == MatchType::PENDING),
      57             :                "Only NOT_FOUND or PENDING make sense with no surface");
      58         121 :     MOZ_ASSERT(mSurface || mMatchType == MatchType::NOT_FOUND ||
      59             :                            mMatchType == MatchType::PENDING,
      60             :                "NOT_FOUND or PENDING do not make sense with a surface");
      61         121 :   }
      62             : 
      63           3 :   LookupResult& operator=(LookupResult&& aOther)
      64             :   {
      65           3 :     MOZ_ASSERT(&aOther != this, "Self-move-assignment is not supported");
      66           3 :     mSurface = Move(aOther.mSurface);
      67           3 :     mMatchType = aOther.mMatchType;
      68           3 :     return *this;
      69             :   }
      70             : 
      71         354 :   DrawableSurface& Surface() { return mSurface; }
      72             :   const DrawableSurface& Surface() const { return mSurface; }
      73             : 
      74             :   /// @return true if this LookupResult contains a surface.
      75         248 :   explicit operator bool() const { return bool(mSurface); }
      76             : 
      77             :   /// @return what kind of match this is (exact, substitute, etc.)
      78         248 :   MatchType Type() const { return mMatchType; }
      79             : 
      80             : private:
      81             :   LookupResult(const LookupResult&) = delete;
      82             : 
      83             :   DrawableSurface mSurface;
      84             :   MatchType mMatchType;
      85             : };
      86             : 
      87             : } // namespace image
      88             : } // namespace mozilla
      89             : 
      90             : #endif // mozilla_image_LookupResult_h