1  /*
 2   * Copyright (C) 2019 Apple, Inc. All rights reserved.
 3   *
 4   * Redistribution and use in source and binary forms, with or without
 5   * modification, are permitted provided that the following conditions
 6   * are met:
 7   * 1. Redistributions of source code must retain the above copyright
 8   *    notice, this list of conditions and the following disclaimer.
 9   * 2. Redistributions in binary form must reproduce the above copyright
10   *    notice, this list of conditions and the following disclaimer in the
11   *    documentation and/or other materials provided with the distribution.
12   *
13   * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
14   * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16   * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
17   * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18   * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19   * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20   * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21   * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23   * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24   */
25  
26  #include "config.h"
27  #include "WeakObjectRefPrototype.h"
28  
29  #include "JSCInlines.h"
30  #include "JSWeakObjectRef.h"
31  
32  namespace JSC {
33  
34  const ClassInfo WeakObjectRefPrototype::s_info = { "WeakRef", &Base::s_info, nullptr, nullptr, CREATE_METHOD_TABLE(WeakObjectRefPrototype) };
35  
36  static JSC_DECLARE_HOST_FUNCTION(protoFuncWeakRefDeref);
37  
38  void WeakObjectRefPrototype::finishCreation(VM& vm, JSGlobalObject* globalObject)
39  {
40      Base::finishCreation(vm);
41      ASSERT(inherits(vm, info()));
42  
43      // FIXME: It wouldn't be hard to make this an intrinsic.
44      JSC_NATIVE_FUNCTION_WITHOUT_TRANSITION(vm.propertyNames->deref, protoFuncWeakRefDeref, static_cast<unsigned>(PropertyAttribute::DontEnum), 0);
45  
46      JSC_TO_STRING_TAG_WITHOUT_TRANSITION();
47  }
48  
49  ALWAYS_INLINE static JSWeakObjectRef* getWeakRef(JSGlobalObject* globalObject, JSValue value)
50  {
51      VM& vm = globalObject->vm();
52      auto scope = DECLARE_THROW_SCOPE(vm);
53  
54      if (UNLIKELY(!value.isObject())) {
55          throwTypeError(globalObject, scope, "Called WeakRef function on non-object"_s);
56          return nullptr;
57      }
58  
59      auto* ref = jsDynamicCast<JSWeakObjectRef*>(vm, asObject(value));
60      if (LIKELY(ref))
61          return ref;
62  
63      throwTypeError(globalObject, scope, "Called WeakRef function on a non-WeakRef object"_s);
64      return nullptr;
65  }
66  
67  JSC_DEFINE_HOST_FUNCTION(protoFuncWeakRefDeref, (JSGlobalObject* globalObject, CallFrame* callFrame))
68  {
69      VM& vm = globalObject->vm();
70      auto* ref = getWeakRef(globalObject, callFrame->thisValue());
71      if (!ref)
72          return JSValue::encode(jsUndefined());
73  
74      auto* value = ref->deref(vm);
75      return value ? JSValue::encode(value) : JSValue::encode(jsNull());
76  }
77  
78  }