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
|
/* -*- 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/. */
#include "vm/ProxyObject.h"
#include "jscompartment.h"
#include "proxy/DeadObjectProxy.h"
#include "proxy/ScriptedProxyHandler.h"
#include "jsobjinlines.h"
using namespace js;
/* static */ ProxyObject*
ProxyObject::New(JSContext* cx, const BaseProxyHandler* handler, HandleValue priv, TaggedProto proto_,
const ProxyOptions& options)
{
Rooted<TaggedProto> proto(cx, proto_);
const Class* clasp = options.clasp();
MOZ_ASSERT(isValidProxyClass(clasp));
MOZ_ASSERT(clasp->shouldDelayMetadataBuilder());
MOZ_ASSERT_IF(proto.isObject(), cx->compartment() == proto.toObject()->compartment());
MOZ_ASSERT(clasp->hasFinalize());
/*
* Eagerly mark properties unknown for proxies, so we don't try to track
* their properties and so that we don't need to walk the compartment if
* their prototype changes later. But don't do this for DOM proxies,
* because we want to be able to keep track of them in typesets in useful
* ways.
*/
if (proto.isObject() && !options.singleton() && !clasp->isDOMClass()) {
RootedObject protoObj(cx, proto.toObject());
if (!JSObject::setNewGroupUnknown(cx, clasp, protoObj))
return nullptr;
}
// Ensure that the wrapper has the same lifetime assumptions as the
// wrappee. Prefer to allocate in the nursery, when possible.
NewObjectKind newKind = NurseryAllocatedProxy;
if (options.singleton()) {
MOZ_ASSERT(priv.isNull() || (priv.isGCThing() && priv.toGCThing()->isTenured()));
newKind = SingletonObject;
} else if ((priv.isGCThing() && priv.toGCThing()->isTenured()) ||
!handler->canNurseryAllocate() ||
!handler->finalizeInBackground(priv))
{
newKind = TenuredObject;
}
gc::AllocKind allocKind = gc::GetGCObjectKind(clasp);
if (handler->finalizeInBackground(priv))
allocKind = GetBackgroundAllocKind(allocKind);
AutoSetNewObjectMetadata metadata(cx);
// Note: this will initialize the object's |data| to strange values, but we
// will immediately overwrite those below.
RootedObject obj(cx, NewObjectWithGivenTaggedProto(cx, clasp, proto, allocKind,
newKind));
if (!obj)
return nullptr;
Rooted<ProxyObject*> proxy(cx, &obj->as<ProxyObject>());
new (proxy->data.values) detail::ProxyValueArray;
proxy->data.handler = handler;
proxy->setCrossCompartmentPrivate(priv);
/* Don't track types of properties of non-DOM and non-singleton proxies. */
if (newKind != SingletonObject && !clasp->isDOMClass())
MarkObjectGroupUnknownProperties(cx, proxy->group());
return proxy;
}
gc::AllocKind
ProxyObject::allocKindForTenure() const
{
gc::AllocKind allocKind = gc::GetGCObjectKind(group()->clasp());
if (data.handler->finalizeInBackground(const_cast<ProxyObject*>(this)->private_()))
allocKind = GetBackgroundAllocKind(allocKind);
return allocKind;
}
/* static */ size_t
ProxyObject::objectMovedDuringMinorGC(TenuringTracer* trc, JSObject* dst, JSObject* src)
{
ProxyObject& psrc = src->as<ProxyObject>();
ProxyObject& pdst = dst->as<ProxyObject>();
// We're about to sweep the nursery heap, so migrate the inline
// ProxyValueArray to the malloc heap if they were nursery allocated.
if (trc->runtime()->gc.nursery.isInside(psrc.data.values))
pdst.data.values = js_new<detail::ProxyValueArray>(*psrc.data.values);
else
trc->runtime()->gc.nursery.removeMallocedBuffer(psrc.data.values);
return sizeof(detail::ProxyValueArray);
}
void
ProxyObject::setCrossCompartmentPrivate(const Value& priv)
{
*slotOfPrivate() = priv;
}
void
ProxyObject::setSameCompartmentPrivate(const Value& priv)
{
MOZ_ASSERT(IsObjectValueInCompartment(priv, compartment()));
*slotOfPrivate() = priv;
}
void
ProxyObject::nuke()
{
// When nuking scripted proxies, isCallable and isConstructor values for
// the proxy needs to be preserved. Do this before clearing the target.
uint32_t callable = handler()->isCallable(this)
? ScriptedProxyHandler::IS_CALLABLE : 0;
uint32_t constructor = handler()->isConstructor(this)
? ScriptedProxyHandler::IS_CONSTRUCTOR : 0;
setExtra(ScriptedProxyHandler::IS_CALLCONSTRUCT_EXTRA,
PrivateUint32Value(callable | constructor));
// Clear the target reference.
setSameCompartmentPrivate(NullValue());
// Update the handler to make this a DeadObjectProxy.
setHandler(&DeadObjectProxy::singleton);
// The proxy's extra slots are not cleared and will continue to be
// traced. This avoids the possibility of triggering write barriers while
// nuking proxies in dead compartments which could otherwise cause those
// compartments to be kept alive. Note that these are slots cannot hold
// cross compartment pointers, so this cannot cause the target compartment
// to leak.
}
JS_FRIEND_API(void)
js::SetValueInProxy(Value* slot, const Value& value)
{
// Slots in proxies are not GCPtrValues, so do a cast whenever assigning
// values to them which might trigger a barrier.
*reinterpret_cast<GCPtrValue*>(slot) = value;
}
|
