gfx/2d/BorrowedContext.h@97036ab72558 (annotated)
gfx/2d/BorrowedContext.h
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: 20; 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 | #ifndef _MOZILLA_GFX_BORROWED_CONTEXT_H |
| michael@0 | 7 | #define _MOZILLA_GFX_BORROWED_CONTEXT_H |
| michael@0 | 8 | |
| michael@0 | 9 | #include "2D.h" |
| michael@0 | 10 | |
| michael@0 | 11 | struct _cairo; |
| michael@0 | 12 | typedef struct _cairo cairo_t; |
| michael@0 | 13 | |
| michael@0 | 14 | namespace mozilla { |
| michael@0 | 15 | |
| michael@0 | 16 | namespace gfx { |
| michael@0 | 17 | |
| michael@0 | 18 | /* This is a helper class that let's you borrow a cairo_t from a |
| michael@0 | 19 | * DrawTargetCairo. This is used for drawing themed widgets. |
| michael@0 | 20 | * |
| michael@0 | 21 | * Callers should check the cr member after constructing the object |
| michael@0 | 22 | * to see if it succeeded. The DrawTarget should not be used while |
| michael@0 | 23 | * the context is borrowed. */ |
| michael@0 | 24 | class BorrowedCairoContext |
| michael@0 | 25 | { |
| michael@0 | 26 | public: |
| michael@0 | 27 | BorrowedCairoContext() |
| michael@0 | 28 | : mCairo(nullptr) |
| michael@0 | 29 | , mDT(nullptr) |
| michael@0 | 30 | { } |
| michael@0 | 31 | |
| michael@0 | 32 | BorrowedCairoContext(DrawTarget *aDT) |
| michael@0 | 33 | : mDT(aDT) |
| michael@0 | 34 | { |
| michael@0 | 35 | mCairo = BorrowCairoContextFromDrawTarget(aDT); |
| michael@0 | 36 | } |
| michael@0 | 37 | |
| michael@0 | 38 | // We can optionally Init after construction in |
| michael@0 | 39 | // case we don't know what the DT will be at construction |
| michael@0 | 40 | // time. |
| michael@0 | 41 | cairo_t *Init(DrawTarget *aDT) |
| michael@0 | 42 | { |
| michael@0 | 43 | MOZ_ASSERT(!mDT, "Can't initialize twice!"); |
| michael@0 | 44 | mDT = aDT; |
| michael@0 | 45 | return mCairo = BorrowCairoContextFromDrawTarget(aDT); |
| michael@0 | 46 | } |
| michael@0 | 47 | |
| michael@0 | 48 | // The caller needs to call Finish if cr is non-null when |
| michael@0 | 49 | // they are done with the context. This is currently explicit |
| michael@0 | 50 | // instead of happening implicitly in the destructor to make |
| michael@0 | 51 | // what's happening in the caller more clear. It also |
| michael@0 | 52 | // let's you resume using the DrawTarget in the same scope. |
| michael@0 | 53 | void Finish() |
| michael@0 | 54 | { |
| michael@0 | 55 | if (mCairo) { |
| michael@0 | 56 | ReturnCairoContextToDrawTarget(mDT, mCairo); |
| michael@0 | 57 | mCairo = nullptr; |
| michael@0 | 58 | } |
| michael@0 | 59 | } |
| michael@0 | 60 | |
| michael@0 | 61 | ~BorrowedCairoContext() { |
| michael@0 | 62 | MOZ_ASSERT(!mCairo); |
| michael@0 | 63 | } |
| michael@0 | 64 | |
| michael@0 | 65 | cairo_t *mCairo; |
| michael@0 | 66 | private: |
| michael@0 | 67 | static cairo_t* BorrowCairoContextFromDrawTarget(DrawTarget *aDT); |
| michael@0 | 68 | static void ReturnCairoContextToDrawTarget(DrawTarget *aDT, cairo_t *aCairo); |
| michael@0 | 69 | DrawTarget *mDT; |
| michael@0 | 70 | }; |
| michael@0 | 71 | |
| michael@0 | 72 | #ifdef XP_MACOSX |
| michael@0 | 73 | /* This is a helper class that let's you borrow a CGContextRef from a |
| michael@0 | 74 | * DrawTargetCG. This is used for drawing themed widgets. |
| michael@0 | 75 | * |
| michael@0 | 76 | * Callers should check the cg member after constructing the object |
| michael@0 | 77 | * to see if it succeeded. The DrawTarget should not be used while |
| michael@0 | 78 | * the context is borrowed. */ |
| michael@0 | 79 | class BorrowedCGContext |
| michael@0 | 80 | { |
| michael@0 | 81 | public: |
| michael@0 | 82 | BorrowedCGContext() |
| michael@0 | 83 | : cg(nullptr) |
| michael@0 | 84 | , mDT(nullptr) |
| michael@0 | 85 | { } |
| michael@0 | 86 | |
| michael@0 | 87 | BorrowedCGContext(DrawTarget *aDT) |
| michael@0 | 88 | : mDT(aDT) |
| michael@0 | 89 | { |
| michael@0 | 90 | cg = BorrowCGContextFromDrawTarget(aDT); |
| michael@0 | 91 | } |
| michael@0 | 92 | |
| michael@0 | 93 | // We can optionally Init after construction in |
| michael@0 | 94 | // case we don't know what the DT will be at construction |
| michael@0 | 95 | // time. |
| michael@0 | 96 | CGContextRef Init(DrawTarget *aDT) |
| michael@0 | 97 | { |
| michael@0 | 98 | MOZ_ASSERT(!mDT, "Can't initialize twice!"); |
| michael@0 | 99 | mDT = aDT; |
| michael@0 | 100 | cg = BorrowCGContextFromDrawTarget(aDT); |
| michael@0 | 101 | return cg; |
| michael@0 | 102 | } |
| michael@0 | 103 | |
| michael@0 | 104 | // The caller needs to call Finish if cg is non-null when |
| michael@0 | 105 | // they are done with the context. This is currently explicit |
| michael@0 | 106 | // instead of happening implicitly in the destructor to make |
| michael@0 | 107 | // what's happening in the caller more clear. It also |
| michael@0 | 108 | // let's you resume using the DrawTarget in the same scope. |
| michael@0 | 109 | void Finish() |
| michael@0 | 110 | { |
| michael@0 | 111 | if (cg) { |
| michael@0 | 112 | ReturnCGContextToDrawTarget(mDT, cg); |
| michael@0 | 113 | cg = nullptr; |
| michael@0 | 114 | } |
| michael@0 | 115 | } |
| michael@0 | 116 | |
| michael@0 | 117 | ~BorrowedCGContext() { |
| michael@0 | 118 | MOZ_ASSERT(!cg); |
| michael@0 | 119 | } |
| michael@0 | 120 | |
| michael@0 | 121 | CGContextRef cg; |
| michael@0 | 122 | private: |
| michael@0 | 123 | static CGContextRef BorrowCGContextFromDrawTarget(DrawTarget *aDT); |
| michael@0 | 124 | static void ReturnCGContextToDrawTarget(DrawTarget *aDT, CGContextRef cg); |
| michael@0 | 125 | DrawTarget *mDT; |
| michael@0 | 126 | }; |
| michael@0 | 127 | #endif |
| michael@0 | 128 | |
| michael@0 | 129 | } |
| michael@0 | 130 | } |
| michael@0 | 131 | |
| michael@0 | 132 | #endif // _MOZILLA_GFX_BORROWED_CONTEXT_H |
