js/xpconnect/public/nsAutoJSValHolder.h@a63d609f5ebe (annotated)
js/xpconnect/public/nsAutoJSValHolder.h
Thu, 15 Jan 2015 15:55:04 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Thu, 15 Jan 2015 15:55:04 +0100
- branch
- TOR_BUG_9701
- changeset 9
- a63d609f5ebe
- permissions
- -rw-r--r--
Back out 97036ab72558 which inappropriately compared turds to third parties.
| michael@0 | 1 | /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ |
| michael@0 | 2 | /* vim: set ts=8 sts=2 et sw=2 tw=80: */ |
| michael@0 | 3 | /* This Source Code Form is subject to the terms of the Mozilla Public |
| michael@0 | 4 | * License, v. 2.0. If a copy of the MPL was not distributed with this |
| michael@0 | 5 | * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ |
| michael@0 | 6 | |
| michael@0 | 7 | #ifndef __NSAUTOJSVALHOLDER_H__ |
| michael@0 | 8 | #define __NSAUTOJSVALHOLDER_H__ |
| michael@0 | 9 | |
| michael@0 | 10 | #include "nsDebug.h" |
| michael@0 | 11 | #include "jsapi.h" |
| michael@0 | 12 | |
| michael@0 | 13 | /** |
| michael@0 | 14 | * Simple class that looks and acts like a JS::Value except that it unroots |
| michael@0 | 15 | * itself automatically if Root() is ever called. Designed to be rooted on the |
| michael@0 | 16 | * context or runtime (but not both!). |
| michael@0 | 17 | */ |
| michael@0 | 18 | class nsAutoJSValHolder |
| michael@0 | 19 | { |
| michael@0 | 20 | public: |
| michael@0 | 21 | nsAutoJSValHolder() |
| michael@0 | 22 | : mVal(JSVAL_NULL), mRt(nullptr) |
| michael@0 | 23 | { |
| michael@0 | 24 | // nothing to do |
| michael@0 | 25 | } |
| michael@0 | 26 | |
| michael@0 | 27 | /** |
| michael@0 | 28 | * Always release on destruction. |
| michael@0 | 29 | */ |
| michael@0 | 30 | virtual ~nsAutoJSValHolder() { |
| michael@0 | 31 | Release(); |
| michael@0 | 32 | } |
| michael@0 | 33 | |
| michael@0 | 34 | nsAutoJSValHolder(const nsAutoJSValHolder& aOther) |
| michael@0 | 35 | : mVal(JSVAL_NULL), mRt(nullptr) |
| michael@0 | 36 | { |
| michael@0 | 37 | *this = aOther; |
| michael@0 | 38 | } |
| michael@0 | 39 | |
| michael@0 | 40 | nsAutoJSValHolder& operator=(const nsAutoJSValHolder& aOther) { |
| michael@0 | 41 | if (this != &aOther) { |
| michael@0 | 42 | if (aOther.IsHeld()) { |
| michael@0 | 43 | // XXX No error handling here... |
| michael@0 | 44 | this->Hold(aOther.mRt); |
| michael@0 | 45 | } |
| michael@0 | 46 | else { |
| michael@0 | 47 | this->Release(); |
| michael@0 | 48 | } |
| michael@0 | 49 | *this = static_cast<JS::Value>(aOther); |
| michael@0 | 50 | } |
| michael@0 | 51 | return *this; |
| michael@0 | 52 | } |
| michael@0 | 53 | |
| michael@0 | 54 | /** |
| michael@0 | 55 | * Hold by rooting on the context's runtime. |
| michael@0 | 56 | */ |
| michael@0 | 57 | bool Hold(JSContext* aCx) { |
| michael@0 | 58 | return Hold(JS_GetRuntime(aCx)); |
| michael@0 | 59 | } |
| michael@0 | 60 | |
| michael@0 | 61 | /** |
| michael@0 | 62 | * Hold by rooting on the runtime. |
| michael@0 | 63 | * Note that mVal may be JSVAL_NULL, which is not a problem. |
| michael@0 | 64 | */ |
| michael@0 | 65 | bool Hold(JSRuntime* aRt) { |
| michael@0 | 66 | MOZ_ASSERT_IF(mRt, mRt == aRt); |
| michael@0 | 67 | |
| michael@0 | 68 | if (!mRt && JS::AddNamedValueRootRT(aRt, &mVal, "nsAutoJSValHolder")) { |
| michael@0 | 69 | mRt = aRt; |
| michael@0 | 70 | } |
| michael@0 | 71 | |
| michael@0 | 72 | return !!mRt; |
| michael@0 | 73 | } |
| michael@0 | 74 | |
| michael@0 | 75 | /** |
| michael@0 | 76 | * Manually release, nullifying mVal, and mRt, but returning |
| michael@0 | 77 | * the original JS::Value. |
| michael@0 | 78 | */ |
| michael@0 | 79 | JS::Value Release() { |
| michael@0 | 80 | JS::Value oldval = mVal; |
| michael@0 | 81 | |
| michael@0 | 82 | if (mRt) { |
| michael@0 | 83 | JS::RemoveValueRootRT(mRt, &mVal); // infallible |
| michael@0 | 84 | mRt = nullptr; |
| michael@0 | 85 | } |
| michael@0 | 86 | |
| michael@0 | 87 | mVal = JSVAL_NULL; |
| michael@0 | 88 | |
| michael@0 | 89 | return oldval; |
| michael@0 | 90 | } |
| michael@0 | 91 | |
| michael@0 | 92 | /** |
| michael@0 | 93 | * Determine if Hold has been called. |
| michael@0 | 94 | */ |
| michael@0 | 95 | bool IsHeld() const { |
| michael@0 | 96 | return !!mRt; |
| michael@0 | 97 | } |
| michael@0 | 98 | |
| michael@0 | 99 | /** |
| michael@0 | 100 | * Explicit JSObject* conversion. |
| michael@0 | 101 | */ |
| michael@0 | 102 | JSObject* ToJSObject() const { |
| michael@0 | 103 | return mVal.isObject() |
| michael@0 | 104 | ? &mVal.toObject() |
| michael@0 | 105 | : nullptr; |
| michael@0 | 106 | } |
| michael@0 | 107 | |
| michael@0 | 108 | /** |
| michael@0 | 109 | * Pretend to be a JS::Value. |
| michael@0 | 110 | */ |
| michael@0 | 111 | operator JS::Value() const { return mVal; } |
| michael@0 | 112 | JS::Value get() const { return mVal; } |
| michael@0 | 113 | |
| michael@0 | 114 | nsAutoJSValHolder &operator=(JSObject* aOther) { |
| michael@0 | 115 | return *this = OBJECT_TO_JSVAL(aOther); |
| michael@0 | 116 | } |
| michael@0 | 117 | |
| michael@0 | 118 | nsAutoJSValHolder &operator=(JS::Value aOther) { |
| michael@0 | 119 | #ifdef DEBUG |
| michael@0 | 120 | if (JSVAL_IS_GCTHING(aOther) && !JSVAL_IS_NULL(aOther)) { |
| michael@0 | 121 | MOZ_ASSERT(IsHeld(), "Not rooted!"); |
| michael@0 | 122 | } |
| michael@0 | 123 | #endif |
| michael@0 | 124 | mVal = aOther; |
| michael@0 | 125 | return *this; |
| michael@0 | 126 | } |
| michael@0 | 127 | |
| michael@0 | 128 | private: |
| michael@0 | 129 | JS::Heap<JS::Value> mVal; |
| michael@0 | 130 | JSRuntime* mRt; |
| michael@0 | 131 | }; |
| michael@0 | 132 | |
| michael@0 | 133 | #endif /* __NSAUTOJSVALHOLDER_H__ */ |
