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| 1 // Copyright 2014 The Chromium Authors. All rights reserved. |
| 2 // Use of this source code is governed by a BSD-style license that can be |
| 3 // found in the LICENSE file. |
| 4 |
| 5 #ifndef ScriptPromiseProperty_h |
| 6 #define ScriptPromiseProperty_h |
| 7 |
| 8 #include "bindings/core/v8/ScriptPromise.h" |
| 9 #include "bindings/core/v8/ScriptPromisePropertyBase.h" |
| 10 #include "bindings/core/v8/V8Binding.h" |
| 11 #include "wtf/Noncopyable.h" |
| 12 #include "wtf/PassRefPtr.h" |
| 13 |
| 14 namespace WebCore { |
| 15 |
| 16 class ExecutionContext; |
| 17 |
| 18 // ScriptPromiseProperty is a helper for implementing a DOM method or |
| 19 // attribute whose value is a Promise, and the same Promise must be |
| 20 // returned each time. |
| 21 // |
| 22 // ScriptPromiseProperty does not keep Promises or worlds alive to |
| 23 // deliver Promise resolution/rejection to them; the Promise |
| 24 // resolution/rejections are delivered if the holder's wrapper is |
| 25 // alive. This is achieved by keeping a weak reference from |
| 26 // ScriptPromiseProperty to the holder's wrapper, and references in |
| 27 // hidden values from the wrapper to the promise and resolver |
| 28 // (coincidentally the Resolver and Promise may be the same object, |
| 29 // but that is an implementation detail of v8.) |
| 30 // |
| 31 // ----> Resolver |
| 32 // / |
| 33 // ScriptPromiseProperty - - -> Holder Wrapper ----> Promise |
| 34 // |
| 35 // To avoid exposing the action of the garbage collector to script, |
| 36 // you should keep the wrapper alive as long as a promise may be |
| 37 // settled. |
| 38 // |
| 39 // ScriptPromiseProperty only supports the main world. |
| 40 // FIXME: Implement support for isolated worlds. |
| 41 template<typename HolderType, typename ResolvedType, typename RejectedType> |
| 42 class ScriptPromiseProperty : public ScriptPromisePropertyBase { |
| 43 WTF_MAKE_NONCOPYABLE(ScriptPromiseProperty); |
| 44 public: |
| 45 // Creates a ScriptPromiseProperty that will create Promises in |
| 46 // the specified ExecutionContext for a property of 'holder' |
| 47 // (typically ScriptPromiseProperty should be a member of the |
| 48 // property holder). |
| 49 // |
| 50 // When implementing a ScriptPromiseProperty add the property name |
| 51 // to ScriptPromiseProperties.h and pass |
| 52 // ScriptPromiseProperty::Foo to create. The name must be unique |
| 53 // per kind of holder. |
| 54 template<typename PassHolderType> |
| 55 static PassRefPtrWillBeRawPtr<ScriptPromiseProperty<HolderType, ResolvedType
, RejectedType> > create(ExecutionContext*, PassHolderType, Name); |
| 56 |
| 57 virtual ~ScriptPromiseProperty() { } |
| 58 |
| 59 template<typename PassResolvedType> |
| 60 void resolve(PassResolvedType); |
| 61 |
| 62 template<typename PassRejectedType> |
| 63 void reject(PassRejectedType); |
| 64 |
| 65 private: |
| 66 template<typename PassHolderType> |
| 67 ScriptPromiseProperty(ExecutionContext*, PassHolderType, Name); |
| 68 |
| 69 virtual v8::Handle<v8::Object> holder(v8::Handle<v8::Object> creationContext
, v8::Isolate*) OVERRIDE; |
| 70 virtual v8::Handle<v8::Value> resolvedValue(v8::Handle<v8::Object> creationC
ontext, v8::Isolate*) OVERRIDE; |
| 71 virtual v8::Handle<v8::Value> rejectedValue(v8::Handle<v8::Object> creationC
ontext, v8::Isolate*) OVERRIDE; |
| 72 |
| 73 HolderType m_holder; |
| 74 ResolvedType m_resolved; |
| 75 RejectedType m_rejected; |
| 76 }; |
| 77 |
| 78 template<typename HolderType, typename ResolvedType, typename RejectedType> |
| 79 template<typename PassHolderType> |
| 80 PassRefPtrWillBeRawPtr<ScriptPromiseProperty<HolderType, ResolvedType, RejectedT
ype> > ScriptPromiseProperty<HolderType, ResolvedType, RejectedType>::create(Exe
cutionContext* executionContext, PassHolderType holder, Name name) |
| 81 { |
| 82 return adoptRef(new ScriptPromiseProperty<HolderType, ResolvedType, Rejected
Type>(executionContext, holder, name)); |
| 83 } |
| 84 |
| 85 template<typename HolderType, typename ResolvedType, typename RejectedType> |
| 86 template<typename PassHolderType> |
| 87 ScriptPromiseProperty<HolderType, ResolvedType, RejectedType>::ScriptPromiseProp
erty(ExecutionContext* executionContext, PassHolderType holder, Name name) |
| 88 : ScriptPromisePropertyBase(executionContext, name) |
| 89 , m_holder(holder) |
| 90 { |
| 91 } |
| 92 |
| 93 template<typename HolderType, typename ResolvedType, typename RejectedType> |
| 94 template<typename PassResolvedType> |
| 95 void ScriptPromiseProperty<HolderType, ResolvedType, RejectedType>::resolve(Pass
ResolvedType value) |
| 96 { |
| 97 if (state() != Pending) { |
| 98 ASSERT_NOT_REACHED(); |
| 99 return; |
| 100 } |
| 101 if (!executionContext()) |
| 102 return; |
| 103 m_resolved = value; |
| 104 resolveOrReject(Resolved); |
| 105 } |
| 106 |
| 107 template<typename HolderType, typename ResolvedType, typename RejectedType> |
| 108 template<typename PassRejectedType> |
| 109 void ScriptPromiseProperty<HolderType, ResolvedType, RejectedType>::reject(PassR
ejectedType value) |
| 110 { |
| 111 if (state() != Pending) { |
| 112 ASSERT_NOT_REACHED(); |
| 113 return; |
| 114 } |
| 115 if (!executionContext()) |
| 116 return; |
| 117 m_rejected = value; |
| 118 resolveOrReject(Rejected); |
| 119 } |
| 120 |
| 121 template<typename HolderType, typename ResolvedType, typename RejectedType> |
| 122 v8::Handle<v8::Object> ScriptPromiseProperty<HolderType, ResolvedType, RejectedT
ype>::holder(v8::Handle<v8::Object> creationContext, v8::Isolate* isolate) |
| 123 { |
| 124 v8::Handle<v8::Value> value = V8ValueTraits<HolderType>::toV8Value(m_holder,
creationContext, isolate); |
| 125 return value.As<v8::Object>(); |
| 126 } |
| 127 |
| 128 template<typename HolderType, typename ResolvedType, typename RejectedType> |
| 129 v8::Handle<v8::Value> ScriptPromiseProperty<HolderType, ResolvedType, RejectedTy
pe>::resolvedValue(v8::Handle<v8::Object> creationContext, v8::Isolate* isolate) |
| 130 { |
| 131 ASSERT(state() == Resolved); |
| 132 return V8ValueTraits<ResolvedType>::toV8Value(m_resolved, creationContext, i
solate); |
| 133 } |
| 134 |
| 135 template<typename HolderType, typename ResolvedType, typename RejectedType> |
| 136 v8::Handle<v8::Value> ScriptPromiseProperty<HolderType, ResolvedType, RejectedTy
pe>::rejectedValue(v8::Handle<v8::Object> creationContext, v8::Isolate* isolate) |
| 137 { |
| 138 ASSERT(state() == Rejected); |
| 139 return V8ValueTraits<RejectedType>::toV8Value(m_rejected, creationContext, i
solate); |
| 140 } |
| 141 |
| 142 } // namespace WebCore |
| 143 |
| 144 #endif // ScriptPromiseProperty_h |
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