gfx/layers/ImageDataSerializer.cpp@97036ab72558
gfx/layers/ImageDataSerializer.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.
1 /* -*- Mode: C++; tab-width: 20; 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/. */
6 #include "ImageDataSerializer.h"
7 #include "gfx2DGlue.h" // for SurfaceFormatToImageFormat
8 #include "gfxImageSurface.h" // for gfxImageSurface
9 #include "gfxPoint.h" // for gfxIntSize
10 #include "mozilla/Assertions.h" // for MOZ_ASSERT, etc
11 #include "mozilla/gfx/2D.h" // for DataSourceSurface, Factory
12 #include "mozilla/gfx/Tools.h" // for GetAlignedStride, etc
13 #include "mozilla/mozalloc.h" // for operator delete, etc
15 namespace mozilla {
16 namespace layers {
18 using namespace gfx;
20 // The Data is layed out as follows:
21 //
22 // +-------------------+ -++ --+ <-- ImageDataSerializerBase::mData pointer
23 // | SurfaceBufferInfo | | |
24 // +-------------------+ --+ | offset
25 // | ... | |
26 // +-------------------+ ------+
27 // | |
28 // | data |
29 // | |
30 // +-------------------+
32 // Structure written at the beginning of the data blob containing the image
33 // (as shown in the figure above). It contains the necessary informations to
34 // read the image in the blob.
35 namespace {
36 struct SurfaceBufferInfo
37 {
38 uint32_t width;
39 uint32_t height;
40 SurfaceFormat format;
42 static uint32_t GetOffset()
43 {
44 return GetAlignedStride<16>(sizeof(SurfaceBufferInfo));
45 }
46 };
47 } // anonymous namespace
49 static SurfaceBufferInfo*
50 GetBufferInfo(uint8_t* aData, size_t aDataSize)
51 {
52 return aDataSize >= sizeof(SurfaceBufferInfo)
53 ? reinterpret_cast<SurfaceBufferInfo*>(aData)
54 : nullptr;
55 }
57 void
58 ImageDataSerializer::InitializeBufferInfo(IntSize aSize,
59 SurfaceFormat aFormat)
60 {
61 SurfaceBufferInfo* info = GetBufferInfo(mData, mDataSize);
62 MOZ_ASSERT(info); // OK to assert here, this method is client-side-only
63 info->width = aSize.width;
64 info->height = aSize.height;
65 info->format = aFormat;
66 Validate();
67 }
69 static inline uint32_t
70 ComputeStride(SurfaceFormat aFormat, uint32_t aWidth)
71 {
72 return GetAlignedStride<4>(BytesPerPixel(aFormat) * aWidth);
73 }
75 uint32_t
76 ImageDataSerializerBase::ComputeMinBufferSize(IntSize aSize,
77 SurfaceFormat aFormat)
78 {
79 uint32_t bufsize = aSize.height * ComputeStride(aFormat, aSize.width);
80 return SurfaceBufferInfo::GetOffset()
81 + GetAlignedStride<16>(bufsize);
82 }
84 void
85 ImageDataSerializerBase::Validate()
86 {
87 mIsValid = false;
88 if (!mData) {
89 return;
90 }
91 SurfaceBufferInfo* info = GetBufferInfo(mData, mDataSize);
92 if (!info) {
93 return;
94 }
95 size_t requiredSize =
96 ComputeMinBufferSize(IntSize(info->width, info->height), info->format);
97 mIsValid = requiredSize <= mDataSize;
98 }
100 uint8_t*
101 ImageDataSerializerBase::GetData()
102 {
103 MOZ_ASSERT(IsValid());
104 return mData + SurfaceBufferInfo::GetOffset();
105 }
107 uint32_t
108 ImageDataSerializerBase::GetStride() const
109 {
110 MOZ_ASSERT(IsValid());
111 SurfaceBufferInfo* info = GetBufferInfo(mData, mDataSize);
112 return ComputeStride(GetFormat(), info->width);
113 }
115 IntSize
116 ImageDataSerializerBase::GetSize() const
117 {
118 MOZ_ASSERT(IsValid());
119 SurfaceBufferInfo* info = GetBufferInfo(mData, mDataSize);
120 return IntSize(info->width, info->height);
121 }
123 SurfaceFormat
124 ImageDataSerializerBase::GetFormat() const
125 {
126 MOZ_ASSERT(IsValid());
127 return GetBufferInfo(mData, mDataSize)->format;
128 }
130 TemporaryRef<gfxImageSurface>
131 ImageDataSerializerBase::GetAsThebesSurface()
132 {
133 MOZ_ASSERT(IsValid());
134 IntSize size = GetSize();
135 return new gfxImageSurface(GetData(),
136 gfxIntSize(size.width, size.height),
137 GetStride(),
138 SurfaceFormatToImageFormat(GetFormat()));
139 }
141 TemporaryRef<DrawTarget>
142 ImageDataSerializerBase::GetAsDrawTarget(gfx::BackendType aBackend)
143 {
144 MOZ_ASSERT(IsValid());
145 return gfx::Factory::CreateDrawTargetForData(aBackend,
146 GetData(), GetSize(),
147 GetStride(), GetFormat());
148 }
150 TemporaryRef<gfx::DataSourceSurface>
151 ImageDataSerializerBase::GetAsSurface()
152 {
153 MOZ_ASSERT(IsValid());
154 return Factory::CreateWrappingDataSourceSurface(GetData(),
155 GetStride(),
156 GetSize(),
157 GetFormat());
158 }
160 } // namespace layers
161 } // namespace mozilla
