The Tor Browser: image/src/FrameSequence.h@ac0c01689b40

Implement a real Private Browsing Mode condition by changing the API/ABI;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.

     1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-

     2  *

     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 mozilla_imagelib_FrameSequence_h_

     8 #define mozilla_imagelib_FrameSequence_h_

    10 #include "nsTArray.h"

    11 #include "mozilla/MemoryReporting.h"

    12 #include "gfxTypes.h"

    13 #include "imgFrame.h"

    15 namespace mozilla {

    16 namespace image {

    18 /**

    19  * FrameDataPair is a slightly-smart tuple of (frame, raw frame data) where the

    20  * raw frame data is allowed to be (and is, initially) null.

    21  *

    22  * If you call LockAndGetData, you will be able to call GetFrameData() on that

    23  * instance, and when the FrameDataPair is destructed, the imgFrame lock will

    24  * be unlocked.

    25  */

    26 class FrameDataPair

    27 {

    28 public:

    29   explicit FrameDataPair(imgFrame* frame)

    30     : mFrame(frame)

    31     , mFrameData(nullptr)

    32   {}

    34   FrameDataPair()

    35     : mFrame(nullptr)

    36     , mFrameData(nullptr)

    37   {}

    39   FrameDataPair(FrameDataPair& other)

    40   {

    41     mFrame = other.mFrame;

    42     mFrameData = other.mFrameData;

    44     // since mFrame is an nsAutoPtr, the assignment operator above actually

    45     // nulls out other.mFrame. In order to fully assume ownership over the

    46     // frame, we also null out the other's mFrameData.

    47     other.mFrameData = nullptr;

    48   }

    50   ~FrameDataPair()

    51   {

    52     if (mFrameData) {

    53       mFrame->UnlockImageData();

    54     }

    55   }

    57   // Lock the frame and store its mFrameData. The frame will be unlocked (and

    58   // deleted) when this FrameDataPair is deleted.

    59   void LockAndGetData()

    60   {

    61     if (mFrame) {

    62       if (NS_SUCCEEDED(mFrame->LockImageData())) {

    63         if (mFrame->GetIsPaletted()) {

    64           mFrameData = reinterpret_cast<uint8_t*>(mFrame->GetPaletteData());

    65         } else {

    66           mFrameData = mFrame->GetImageData();

    67         }

    68       }

    69     }

    70   }

    72   // Null out this FrameDataPair and return its frame. You must ensure the

    73   // frame will be deleted separately.

    74   imgFrame* Forget()

    75   {

    76     if (mFrameData) {

    77       mFrame->UnlockImageData();

    78     }

    80     imgFrame* frame = mFrame.forget();

    81     mFrameData = nullptr;

    82     return frame;

    83   }

    85   bool HasFrameData() const

    86   {

    87     if (mFrameData) {

    88       MOZ_ASSERT(!!mFrame);

    89     }

    90     return !!mFrameData;

    91   }

    93   uint8_t* GetFrameData() const

    94   {

    95     return mFrameData;

    96   }

    98   imgFrame* GetFrame() const

    99   {

   100     return mFrame;

   101   }

   103   // Resets this FrameDataPair to work with a different frame. Takes ownership

   104   // of the frame, deleting the old frame (if any).

   105   void SetFrame(imgFrame* frame)

   106   {

   107     if (mFrameData) {

   108       mFrame->UnlockImageData();

   109     }

   111     mFrame = frame;

   112     mFrameData = nullptr;

   113   }

   115   operator imgFrame*() const

   116   {

   117     return GetFrame();

   118   }

   120   imgFrame* operator->() const

   121   {

   122     return GetFrame();

   123   }

   125   bool operator==(imgFrame* other) const

   126   {

   127     return mFrame == other;

   128   }

   130 private:

   131   nsAutoPtr<imgFrame> mFrame;

   132   uint8_t* mFrameData;

   133 };

   135 /**

   136  * FrameSequence stores image frames (and their associated raw data pointers).

   137  * It is little more than a smart array.

   138  */

   139 class FrameSequence

   140 {

   141 public:

   143   ~FrameSequence();

   145   NS_INLINE_DECL_THREADSAFE_REFCOUNTING(FrameSequence)

   147   /**

   148    * Get the read-only (frame, data) pair at index aIndex.

   149    */

   150   const FrameDataPair& GetFrame(uint32_t aIndex) const;

   152   /**

   153    * Insert a frame into the array. FrameSequence takes ownership of the frame.

   154    */

   155   void InsertFrame(uint32_t framenum, imgFrame* aFrame);

   157   /**

   158    * Remove (and delete) the frame at index framenum.

   159    */

   160   void RemoveFrame(uint32_t framenum);

   162   /**

   163    * Swap aFrame with the frame at sequence framenum, and return that frame.

   164    * You take ownership over the frame returned.

   165    */

   166   imgFrame* SwapFrame(uint32_t framenum, imgFrame* aFrame);

   168   /**

   169    * Remove (and delete) all frames.

   170    */

   171   void ClearFrames();

   173   /* The total number of frames in this image. */

   174   uint32_t GetNumFrames() const;

   176   size_t SizeOfDecodedWithComputedFallbackIfHeap(gfxMemoryLocation aLocation,

   177                                                  mozilla::MallocSizeOf aMallocSizeOf) const;

   179 private: // data

   180   //! All the frames of the image

   181   nsTArray<FrameDataPair> mFrames;

   182 };

   184 } // namespace image

   185 } // namespace mozilla

   187 #endif /* mozilla_imagelib_FrameSequence_h_ */

The Tor Browser / file revision

image/src/FrameSequence.h@ac0c01689b40

image/src/FrameSequence.h