gfx/layers/LayerUtils.cpp@97036ab72558 (annotated)
gfx/layers/LayerUtils.cpp
Tue, 06 Jan 2015 21:39:09 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Tue, 06 Jan 2015 21:39:09 +0100
- branch
- TOR_BUG_9701
- changeset 8
- 97036ab72558
- permissions
- -rw-r--r--
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.
| michael@0 | 1 | /* -*- Mode: c++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ |
| michael@0 | 2 | /* This Source Code Form is subject to the terms of the Mozilla Public |
| michael@0 | 3 | * License, v. 2.0. If a copy of the MPL was not distributed with this |
| michael@0 | 4 | * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ |
| michael@0 | 5 | |
| michael@0 | 6 | #include "LayerUtils.h" |
| michael@0 | 7 | #include "PremultiplyTables.h" |
| michael@0 | 8 | #include "mozilla/Endian.h" |
| michael@0 | 9 | |
| michael@0 | 10 | namespace mozilla { |
| michael@0 | 11 | namespace layers { |
| michael@0 | 12 | |
| michael@0 | 13 | using namespace mozilla::gfx; |
| michael@0 | 14 | |
| michael@0 | 15 | static inline const uint8_t PremultiplyValue(uint8_t a, uint8_t v) { |
| michael@0 | 16 | return PremultiplyTable[a*256+v]; |
| michael@0 | 17 | } |
| michael@0 | 18 | |
| michael@0 | 19 | static inline const uint8_t UnpremultiplyValue(uint8_t a, uint8_t v) { |
| michael@0 | 20 | return UnpremultiplyTable[a*256+v]; |
| michael@0 | 21 | } |
| michael@0 | 22 | |
| michael@0 | 23 | #ifdef DEBUG |
| michael@0 | 24 | static bool IsLittleEndian() |
| michael@0 | 25 | { |
| michael@0 | 26 | // Violate strict aliasing, because violating strict aliasing is how |
| michael@0 | 27 | // we always pack and unpack between uint32_t and uint8_t[]. |
| michael@0 | 28 | uint16_t testShort; |
| michael@0 | 29 | static const uint8_t testBytes[2] = { 0xAA, 0xBB }; |
| michael@0 | 30 | memcpy(&testShort, testBytes, sizeof(testBytes)); |
| michael@0 | 31 | return testShort == 0xBBAA; |
| michael@0 | 32 | } |
| michael@0 | 33 | #endif // DEBUG |
| michael@0 | 34 | |
| michael@0 | 35 | #ifdef MOZ_LITTLE_ENDIAN |
| michael@0 | 36 | #define ASSERT_ENDIAN() MOZ_ASSERT(IsLittleEndian(), "Defined as little endian, but actually big!") |
| michael@0 | 37 | #else |
| michael@0 | 38 | #define ASSERT_ENDIAN() MOZ_ASSERT(!IsLittleEndian(), "Defined as big endian, but actually little!") |
| michael@0 | 39 | #endif |
| michael@0 | 40 | |
| michael@0 | 41 | void |
| michael@0 | 42 | PremultiplySurface(DataSourceSurface* srcSurface, |
| michael@0 | 43 | DataSourceSurface* destSurface) |
| michael@0 | 44 | { |
| michael@0 | 45 | if (!destSurface) |
| michael@0 | 46 | destSurface = srcSurface; |
| michael@0 | 47 | |
| michael@0 | 48 | IntSize srcSize = srcSurface->GetSize(); |
| michael@0 | 49 | MOZ_ASSERT(srcSurface->GetFormat() == destSurface->GetFormat() && |
| michael@0 | 50 | srcSize.width == destSurface->GetSize().width && |
| michael@0 | 51 | srcSize.height == destSurface->GetSize().height && |
| michael@0 | 52 | srcSurface->Stride() == destSurface->Stride(), |
| michael@0 | 53 | "Source and destination surfaces don't have identical characteristics"); |
| michael@0 | 54 | |
| michael@0 | 55 | MOZ_ASSERT(srcSurface->Stride() == srcSize.width * 4, |
| michael@0 | 56 | "Source surface stride isn't tightly packed"); |
| michael@0 | 57 | |
| michael@0 | 58 | // Only premultiply ARGB32 |
| michael@0 | 59 | if (srcSurface->GetFormat() != SurfaceFormat::B8G8R8A8) { |
| michael@0 | 60 | if (destSurface != srcSurface) { |
| michael@0 | 61 | memcpy(destSurface->GetData(), srcSurface->GetData(), |
| michael@0 | 62 | srcSurface->Stride() * srcSize.height); |
| michael@0 | 63 | } |
| michael@0 | 64 | return; |
| michael@0 | 65 | } |
| michael@0 | 66 | |
| michael@0 | 67 | uint8_t *src = srcSurface->GetData(); |
| michael@0 | 68 | uint8_t *dst = destSurface->GetData(); |
| michael@0 | 69 | |
| michael@0 | 70 | // Assert that our endian define is correct. |
| michael@0 | 71 | ASSERT_ENDIAN(); |
| michael@0 | 72 | |
| michael@0 | 73 | uint32_t dim = srcSize.width * srcSize.height; |
| michael@0 | 74 | for (uint32_t i = 0; i < dim; ++i) { |
| michael@0 | 75 | #ifdef MOZ_LITTLE_ENDIAN |
| michael@0 | 76 | uint8_t b = *src++; |
| michael@0 | 77 | uint8_t g = *src++; |
| michael@0 | 78 | uint8_t r = *src++; |
| michael@0 | 79 | uint8_t a = *src++; |
| michael@0 | 80 | |
| michael@0 | 81 | *dst++ = PremultiplyValue(a, b); |
| michael@0 | 82 | *dst++ = PremultiplyValue(a, g); |
| michael@0 | 83 | *dst++ = PremultiplyValue(a, r); |
| michael@0 | 84 | *dst++ = a; |
| michael@0 | 85 | #else |
| michael@0 | 86 | uint8_t a = *src++; |
| michael@0 | 87 | uint8_t r = *src++; |
| michael@0 | 88 | uint8_t g = *src++; |
| michael@0 | 89 | uint8_t b = *src++; |
| michael@0 | 90 | |
| michael@0 | 91 | *dst++ = a; |
| michael@0 | 92 | *dst++ = PremultiplyValue(a, r); |
| michael@0 | 93 | *dst++ = PremultiplyValue(a, g); |
| michael@0 | 94 | *dst++ = PremultiplyValue(a, b); |
| michael@0 | 95 | #endif |
| michael@0 | 96 | } |
| michael@0 | 97 | } |
| michael@0 | 98 | |
| michael@0 | 99 | |
| michael@0 | 100 | } |
| michael@0 | 101 | } |
