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
|
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* 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 mozilla_dom_DOMJSProxyHandler_h
#define mozilla_dom_DOMJSProxyHandler_h
#include "js/Object.h" // JS::GetClass
#include "js/Proxy.h"
#include "jsapi.h"
#include "mozilla/Assertions.h"
#include "mozilla/Maybe.h"
namespace mozilla::dom {
/**
* DOM proxies store the expando object in the private slot.
*
* The expando object is a plain JSObject whose properties correspond to
* "expandos" (custom properties set by the script author).
*
* The exact value stored in the proxy's private slot depends on whether the
* interface is annotated with the [OverrideBuiltins] extended attribute.
*
* If it is, the proxy is initialized with a PrivateValue, which contains a
* pointer to a JS::ExpandoAndGeneration object; this contains a pointer to
* the actual expando object as well as the "generation" of the object. The
* proxy handler will trace the expando object stored in the
* JS::ExpandoAndGeneration while the proxy itself is alive.
*
* If it is not, the proxy is initialized with an UndefinedValue. In
* EnsureExpandoObject, it is set to an ObjectValue that points to the
* expando object directly. (It is set back to an UndefinedValue only when
* the object is about to die.)
*/
class BaseDOMProxyHandler : public js::BaseProxyHandler {
public:
explicit constexpr BaseDOMProxyHandler(const void* aProxyFamily,
bool aHasPrototype = false)
: js::BaseProxyHandler(aProxyFamily, aHasPrototype) {}
// Implementations of methods that can be implemented in terms of
// other lower-level methods.
bool getOwnPropertyDescriptor(
JSContext* cx, JS::Handle<JSObject*> proxy, JS::Handle<jsid> id,
JS::MutableHandle<Maybe<JS::PropertyDescriptor>> desc) const override;
virtual bool ownPropertyKeys(
JSContext* cx, JS::Handle<JSObject*> proxy,
JS::MutableHandleVector<jsid> props) const override;
virtual bool getPrototypeIfOrdinary(
JSContext* cx, JS::Handle<JSObject*> proxy, bool* isOrdinary,
JS::MutableHandle<JSObject*> proto) const override;
// We override getOwnEnumerablePropertyKeys() and implement it directly
// instead of using the default implementation, which would call
// ownPropertyKeys and then filter out the non-enumerable ones. This avoids
// unnecessary work during enumeration.
virtual bool getOwnEnumerablePropertyKeys(
JSContext* cx, JS::Handle<JSObject*> proxy,
JS::MutableHandleVector<jsid> props) const override;
protected:
// Hook for subclasses to implement shared ownPropertyKeys()/keys()
// functionality. The "flags" argument is either JSITER_OWNONLY (for keys())
// or JSITER_OWNONLY | JSITER_HIDDEN | JSITER_SYMBOLS (for
// ownPropertyKeys()).
virtual bool ownPropNames(JSContext* cx, JS::Handle<JSObject*> proxy,
unsigned flags,
JS::MutableHandleVector<jsid> props) const = 0;
// Hook for subclasses to allow set() to ignore named props while other things
// that look at property descriptors see them. This is intentionally not
// named getOwnPropertyDescriptor to avoid subclasses that override it hiding
// our public getOwnPropertyDescriptor.
virtual bool getOwnPropDescriptor(
JSContext* cx, JS::Handle<JSObject*> proxy, JS::Handle<jsid> id,
bool ignoreNamedProps,
JS::MutableHandle<Maybe<JS::PropertyDescriptor>> desc) const = 0;
};
class DOMProxyHandler : public BaseDOMProxyHandler {
public:
constexpr DOMProxyHandler() : BaseDOMProxyHandler(&family) {}
bool defineProperty(JSContext* cx, JS::Handle<JSObject*> proxy,
JS::Handle<jsid> id,
JS::Handle<JS::PropertyDescriptor> desc,
JS::ObjectOpResult& result) const override {
bool unused;
return defineProperty(cx, proxy, id, desc, result, &unused);
}
virtual bool defineProperty(JSContext* cx, JS::Handle<JSObject*> proxy,
JS::Handle<jsid> id,
JS::Handle<JS::PropertyDescriptor> desc,
JS::ObjectOpResult& result, bool* done) const;
bool delete_(JSContext* cx, JS::Handle<JSObject*> proxy, JS::Handle<jsid> id,
JS::ObjectOpResult& result) const override;
bool preventExtensions(JSContext* cx, JS::Handle<JSObject*> proxy,
JS::ObjectOpResult& result) const override;
bool isExtensible(JSContext* cx, JS::Handle<JSObject*> proxy,
bool* extensible) const override;
bool set(JSContext* cx, JS::Handle<JSObject*> proxy, JS::Handle<jsid> id,
JS::Handle<JS::Value> v, JS::Handle<JS::Value> receiver,
JS::ObjectOpResult& result) const override;
/*
* If assigning to proxy[id] hits a named setter with OverrideBuiltins or
* an indexed setter, call it and set *done to true on success. Otherwise, set
* *done to false.
*/
virtual bool setCustom(JSContext* cx, JS::Handle<JSObject*> proxy,
JS::Handle<jsid> id, JS::Handle<JS::Value> v,
bool* done) const;
/*
* Get the expando object for the given DOM proxy.
*/
static JSObject* GetExpandoObject(JSObject* obj);
/*
* Clear the expando object for the given DOM proxy and return it. This
* function will ensure that the returned object is exposed to active JS if
* the given object is exposed.
*
* GetAndClearExpandoObject does not DROP or clear the preserving wrapper
* flag.
*/
static JSObject* GetAndClearExpandoObject(JSObject* obj);
/*
* Ensure that the given proxy (obj) has an expando object, and return it.
* Returns null on failure.
*/
static JSObject* EnsureExpandoObject(JSContext* cx,
JS::Handle<JSObject*> obj);
static const char family;
};
// Class used by shadowing handlers (the ones that have [OverrideBuiltins].
// This handles tracing the expando in JS::ExpandoAndGeneration.
class ShadowingDOMProxyHandler : public DOMProxyHandler {
public:
virtual void trace(JSTracer* trc, JSObject* proxy) const override;
};
inline bool IsDOMProxy(JSObject* obj) {
return js::IsProxy(obj) &&
js::GetProxyHandler(obj)->family() == &DOMProxyHandler::family;
}
inline const DOMProxyHandler* GetDOMProxyHandler(JSObject* obj) {
MOZ_ASSERT(IsDOMProxy(obj));
return static_cast<const DOMProxyHandler*>(js::GetProxyHandler(obj));
}
} // namespace mozilla::dom
#endif /* mozilla_dom_DOMProxyHandler_h */
|
