1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/dom/xbl/nsXBLMaybeCompiled.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,156 @@
1.4 +/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
1.5 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.6 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.7 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.8 +
1.9 +#ifndef nsXBLMaybeCompiled_h__
1.10 +#define nsXBLMaybeCompiled_h__
1.11 +
1.12 +#include "js/GCAPI.h"
1.13 +
1.14 +/*
1.15 + * A union containing either a pointer representing uncompiled source or a
1.16 + * JSObject* representing the compiled result. The class is templated on the
1.17 + * source object type.
1.18 + *
1.19 + * The purpose of abstracting this as a separate class is to allow it to be
1.20 + * wrapped in a JS::Heap<T> to correctly handle post-barriering of the JSObject
1.21 + * pointer, when present.
1.22 + */
1.23 +template <class UncompiledT>
1.24 +class nsXBLMaybeCompiled
1.25 +{
1.26 +public:
1.27 + nsXBLMaybeCompiled() : mUncompiled(BIT_UNCOMPILED) {}
1.28 +
1.29 + nsXBLMaybeCompiled(UncompiledT* uncompiled)
1.30 + : mUncompiled(reinterpret_cast<uintptr_t>(uncompiled) | BIT_UNCOMPILED) {}
1.31 +
1.32 + nsXBLMaybeCompiled(JSObject* compiled) : mCompiled(compiled) {}
1.33 +
1.34 + bool IsCompiled() const
1.35 + {
1.36 + return !(mUncompiled & BIT_UNCOMPILED);
1.37 + }
1.38 +
1.39 + UncompiledT* GetUncompiled() const
1.40 + {
1.41 + MOZ_ASSERT(!IsCompiled(), "Attempt to get compiled function as uncompiled");
1.42 + uintptr_t unmasked = mUncompiled & ~BIT_UNCOMPILED;
1.43 + return reinterpret_cast<UncompiledT*>(unmasked);
1.44 + }
1.45 +
1.46 + JSObject* GetJSFunction() const
1.47 + {
1.48 + MOZ_ASSERT(IsCompiled(), "Attempt to get uncompiled function as compiled");
1.49 + if (mCompiled) {
1.50 + JS::ExposeObjectToActiveJS(mCompiled);
1.51 + }
1.52 + return mCompiled;
1.53 + }
1.54 +
1.55 + // This is appropriate for use in tracing methods, etc.
1.56 + JSObject* GetJSFunctionPreserveColor() const
1.57 + {
1.58 + MOZ_ASSERT(IsCompiled(), "Attempt to get uncompiled function as compiled");
1.59 + return mCompiled;
1.60 + }
1.61 +
1.62 +private:
1.63 + JSObject*& UnsafeGetJSFunction()
1.64 + {
1.65 + MOZ_ASSERT(IsCompiled(), "Attempt to get uncompiled function as compiled");
1.66 + return mCompiled;
1.67 + }
1.68 +
1.69 + enum { BIT_UNCOMPILED = 1 << 0 };
1.70 +
1.71 + union
1.72 + {
1.73 + // An pointer that represents the function before being compiled, with
1.74 + // BIT_UNCOMPILED set.
1.75 + uintptr_t mUncompiled;
1.76 +
1.77 + // The JS object for the compiled result.
1.78 + JSObject* mCompiled;
1.79 + };
1.80 +
1.81 + friend class js::GCMethods<nsXBLMaybeCompiled<UncompiledT> >;
1.82 +};
1.83 +
1.84 +/* Add support for JS::Heap<nsXBLMaybeCompiled>. */
1.85 +namespace js {
1.86 +
1.87 +template <class UncompiledT>
1.88 +struct GCMethods<nsXBLMaybeCompiled<UncompiledT> > : public GCMethods<JSObject *>
1.89 +{
1.90 + typedef struct GCMethods<JSObject *> Base;
1.91 +
1.92 + static nsXBLMaybeCompiled<UncompiledT> initial() { return nsXBLMaybeCompiled<UncompiledT>(); }
1.93 +
1.94 + static bool poisoned(nsXBLMaybeCompiled<UncompiledT> function)
1.95 + {
1.96 + return function.IsCompiled() && Base::poisoned(function.GetJSFunction());
1.97 + }
1.98 +
1.99 + static bool needsPostBarrier(nsXBLMaybeCompiled<UncompiledT> function)
1.100 + {
1.101 + return function.IsCompiled() && Base::needsPostBarrier(function.GetJSFunction());
1.102 + }
1.103 +
1.104 +#ifdef JSGC_GENERATIONAL
1.105 + static void postBarrier(nsXBLMaybeCompiled<UncompiledT>* functionp)
1.106 + {
1.107 + Base::postBarrier(&functionp->UnsafeGetJSFunction());
1.108 + }
1.109 +
1.110 + static void relocate(nsXBLMaybeCompiled<UncompiledT>* functionp)
1.111 + {
1.112 + Base::relocate(&functionp->UnsafeGetJSFunction());
1.113 + }
1.114 +#endif
1.115 +};
1.116 +
1.117 +template <class UncompiledT>
1.118 +class HeapBase<nsXBLMaybeCompiled<UncompiledT> >
1.119 +{
1.120 + const JS::Heap<nsXBLMaybeCompiled<UncompiledT> >& wrapper() const {
1.121 + return *static_cast<const JS::Heap<nsXBLMaybeCompiled<UncompiledT> >*>(this);
1.122 + }
1.123 +
1.124 + JS::Heap<nsXBLMaybeCompiled<UncompiledT> >& wrapper() {
1.125 + return *static_cast<JS::Heap<nsXBLMaybeCompiled<UncompiledT> >*>(this);
1.126 + }
1.127 +
1.128 + const nsXBLMaybeCompiled<UncompiledT>* extract() const {
1.129 + return wrapper().address();
1.130 + }
1.131 +
1.132 + nsXBLMaybeCompiled<UncompiledT>* extract() {
1.133 + return wrapper().unsafeGet();
1.134 + }
1.135 +
1.136 +public:
1.137 + bool IsCompiled() const { return extract()->IsCompiled(); }
1.138 + UncompiledT* GetUncompiled() const { return extract()->GetUncompiled(); }
1.139 + JSObject* GetJSFunction() const { return extract()->GetJSFunction(); }
1.140 + JSObject* GetJSFunctionPreserveColor() const { return extract()->GetJSFunctionPreserveColor(); }
1.141 +
1.142 + void SetUncompiled(UncompiledT* source) {
1.143 + wrapper().set(nsXBLMaybeCompiled<UncompiledT>(source));
1.144 + }
1.145 +
1.146 + void SetJSFunction(JSObject* function) {
1.147 + wrapper().set(nsXBLMaybeCompiled<UncompiledT>(function));
1.148 + }
1.149 +
1.150 + JS::Heap<JSObject*>& AsHeapObject()
1.151 + {
1.152 + MOZ_ASSERT(extract()->IsCompiled());
1.153 + return *reinterpret_cast<JS::Heap<JSObject*>*>(this);
1.154 + }
1.155 +};
1.156 +
1.157 +} /* namespace js */
1.158 +
1.159 +#endif // nsXBLMaybeCompiled_h__
