/usr/include/thunderbird/js/GCVariant.h is in thunderbird-dev 1:52.8.0-1~deb8u1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 | /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
* vim: set ts=8 sts=4 et sw=4 tw=99:
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef js_GCVariant_h
#define js_GCVariant_h
#include "mozilla/Variant.h"
#include "js/GCPolicyAPI.h"
#include "js/RootingAPI.h"
#include "js/TracingAPI.h"
namespace JS {
// These template specializations allow Variant to be used inside GC wrappers.
//
// When matching on GC wrappers around Variants, matching should be done on
// the wrapper itself. The matcher class's methods should take Handles or
// MutableHandles. For example,
//
// struct MyMatcher
// {
// using ReturnType = const char*;
// ReturnType match(HandleObject o) { return "object"; }
// ReturnType match(HandleScript s) { return "script"; }
// };
//
// Rooted<Variant<JSObject*, JSScript*>> v(cx, someScript);
// MyMatcher mm;
// v.match(mm);
//
// If you get compile errors about inability to upcast subclasses (e.g., from
// NativeObject* to JSObject*) and are inside js/src, be sure to also include
// "gc/Policy.h".
namespace detail {
template <typename... Ts>
struct GCVariantImplementation;
// The base case.
template <typename T>
struct GCVariantImplementation<T>
{
template <typename ConcreteVariant>
static void trace(JSTracer* trc, ConcreteVariant* v, const char* name) {
T& thing = v->template as<T>();
if (!mozilla::IsPointer<T>::value || thing)
GCPolicy<T>::trace(trc, &thing, name);
}
template <typename Matcher, typename ConcreteVariant>
static typename Matcher::ReturnType
match(Matcher& matcher, Handle<ConcreteVariant> v) {
const T& thing = v.get().template as<T>();
return matcher.match(Handle<T>::fromMarkedLocation(&thing));
}
template <typename Matcher, typename ConcreteVariant>
static typename Matcher::ReturnType
match(Matcher& matcher, MutableHandle<ConcreteVariant> v) {
T& thing = v.get().template as<T>();
return matcher.match(MutableHandle<T>::fromMarkedLocation(&thing));
}
};
// The inductive case.
template <typename T, typename... Ts>
struct GCVariantImplementation<T, Ts...>
{
using Next = GCVariantImplementation<Ts...>;
template <typename ConcreteVariant>
static void trace(JSTracer* trc, ConcreteVariant* v, const char* name) {
if (v->template is<T>()) {
T& thing = v->template as<T>();
if (!mozilla::IsPointer<T>::value || thing)
GCPolicy<T>::trace(trc, &thing, name);
} else {
Next::trace(trc, v, name);
}
}
template <typename Matcher, typename ConcreteVariant>
static typename Matcher::ReturnType
match(Matcher& matcher, Handle<ConcreteVariant> v) {
if (v.get().template is<T>()) {
const T& thing = v.get().template as<T>();
return matcher.match(Handle<T>::fromMarkedLocation(&thing));
}
return Next::match(matcher, v);
}
template <typename Matcher, typename ConcreteVariant>
static typename Matcher::ReturnType
match(Matcher& matcher, MutableHandle<ConcreteVariant> v) {
if (v.get().template is<T>()) {
T& thing = v.get().template as<T>();
return matcher.match(MutableHandle<T>::fromMarkedLocation(&thing));
}
return Next::match(matcher, v);
}
};
} // namespace detail
template <typename... Ts>
struct GCPolicy<mozilla::Variant<Ts...>>
{
using Impl = detail::GCVariantImplementation<Ts...>;
// Variants do not provide initial(). They do not have a default initial
// value and one must be provided.
static void trace(JSTracer* trc, mozilla::Variant<Ts...>* v, const char* name) {
Impl::trace(trc, v, name);
}
};
} // namespace JS
namespace js {
template <typename Outer, typename... Ts>
class GCVariantOperations
{
using Impl = JS::detail::GCVariantImplementation<Ts...>;
using Variant = mozilla::Variant<Ts...>;
const Variant& variant() const { return static_cast<const Outer*>(this)->get(); }
public:
template <typename T>
bool is() const {
return variant().template is<T>();
}
template <typename T>
JS::Handle<T> as() const {
return Handle<T>::fromMarkedLocation(&variant().template as<T>());
}
template <typename Matcher>
typename Matcher::ReturnType
match(Matcher& matcher) const {
return Impl::match(matcher, JS::Handle<Variant>::fromMarkedLocation(&variant()));
}
};
template <typename Outer, typename... Ts>
class MutableGCVariantOperations
: public GCVariantOperations<Outer, Ts...>
{
using Impl = JS::detail::GCVariantImplementation<Ts...>;
using Variant = mozilla::Variant<Ts...>;
const Variant& variant() const { return static_cast<const Outer*>(this)->get(); }
Variant& variant() { return static_cast<Outer*>(this)->get(); }
public:
template <typename T>
JS::MutableHandle<T> as() {
return JS::MutableHandle<T>::fromMarkedLocation(&variant().template as<T>());
}
template <typename Matcher>
typename Matcher::ReturnType
match(Matcher& matcher) {
return Impl::match(matcher, JS::MutableHandle<Variant>::fromMarkedLocation(&variant()));
}
};
template <typename... Ts>
class RootedBase<mozilla::Variant<Ts...>>
: public MutableGCVariantOperations<JS::Rooted<mozilla::Variant<Ts...>>, Ts...>
{ };
template <typename... Ts>
class MutableHandleBase<mozilla::Variant<Ts...>>
: public MutableGCVariantOperations<JS::MutableHandle<mozilla::Variant<Ts...>>, Ts...>
{ };
template <typename... Ts>
class HandleBase<mozilla::Variant<Ts...>>
: public GCVariantOperations<JS::Handle<mozilla::Variant<Ts...>>, Ts...>
{ };
template <typename... Ts>
class PersistentRootedBase<mozilla::Variant<Ts...>>
: public MutableGCVariantOperations<JS::PersistentRooted<mozilla::Variant<Ts...>>, Ts...>
{ };
} // namespace js
#endif // js_GCVariant_h
|