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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 MOJO_SERVICES_VIEW_MANAGER_PUBLIC_CPP_VIEW_PROPERTY_H_ | |
6 #define MOJO_SERVICES_VIEW_MANAGER_PUBLIC_CPP_VIEW_PROPERTY_H_ | |
7 | |
8 #include <stdint.h> | |
9 | |
10 // This header should be included by code that defines ViewProperties. It | |
11 // should not be included by code that only gets and sets ViewProperties. | |
12 // | |
13 // To define a new ViewProperty: | |
14 // | |
15 // #include "view_manager/public/cpp/view_property.h" | |
16 // | |
17 // DECLARE_EXPORTED_VIEW_PROPERTY_TYPE(FOO_EXPORT, MyType); | |
18 // namespace foo { | |
19 // // Use this to define an exported property that is premitive, | |
20 // // or a pointer you don't want automatically deleted. | |
21 // DEFINE_VIEW_PROPERTY_KEY(MyType, kMyKey, MyDefault); | |
22 // | |
23 // // Use this to define an exported property whose value is a heap | |
24 // // allocated object, and has to be owned and freed by the view. | |
25 // DEFINE_OWNED_VIEW_PROPERTY_KEY(gfx::Rect, kRestoreBoundsKey, nullptr); | |
26 // | |
27 // // Use this to define a non exported property that is primitive, | |
28 // // or a pointer you don't want to automatically deleted, and is used | |
29 // // only in a specific file. This will define the property in an unnamed | |
30 // // namespace which cannot be accessed from another file. | |
31 // DEFINE_LOCAL_VIEW_PROPERTY_KEY(MyType, kMyKey, MyDefault); | |
32 // | |
33 // } // foo namespace | |
34 // | |
35 // To define a new type used for ViewProperty. | |
36 // | |
37 // // outside all namespaces: | |
38 // DECLARE_EXPORTED_VIEW_PROPERTY_TYPE(FOO_EXPORT, MyType) | |
39 // | |
40 // If a property type is not exported, use DECLARE_VIEW_PROPERTY_TYPE(MyType) | |
41 // which is a shorthand for DECLARE_EXPORTED_VIEW_PROPERTY_TYPE(, MyType). | |
42 | |
43 namespace mojo { | |
44 namespace { | |
45 | |
46 // No single new-style cast works for every conversion to/from int64_t, so we | |
47 // need this helper class. A third specialization is needed for bool because | |
48 // MSVC warning C4800 (forcing value to bool) is not suppressed by an explicit | |
49 // cast (!). | |
50 template <typename T> | |
51 class ViewPropertyCaster { | |
52 public: | |
53 static int64_t ToInt64(T x) { return static_cast<int64_t>(x); } | |
54 static T FromInt64(int64_t x) { return static_cast<T>(x); } | |
55 }; | |
56 template <typename T> | |
57 class ViewPropertyCaster<T*> { | |
58 public: | |
59 static int64_t ToInt64(T* x) { return reinterpret_cast<int64_t>(x); } | |
60 static T* FromInt64(int64_t x) { return reinterpret_cast<T*>(x); } | |
61 }; | |
62 template <> | |
63 class ViewPropertyCaster<bool> { | |
64 public: | |
65 static int64_t ToInt64(bool x) { return static_cast<int64_t>(x); } | |
66 static bool FromInt64(int64_t x) { return x != 0; } | |
67 }; | |
68 | |
69 } // namespace | |
70 | |
71 template <typename T> | |
72 struct ViewProperty { | |
73 T default_value; | |
74 const char* name; | |
75 View::PropertyDeallocator deallocator; | |
76 }; | |
77 | |
78 template <typename T> | |
79 void View::SetLocalProperty(const ViewProperty<T>* property, T value) { | |
80 int64_t old = SetLocalPropertyInternal( | |
81 property, property->name, | |
82 value == property->default_value ? nullptr : property->deallocator, | |
83 ViewPropertyCaster<T>::ToInt64(value), | |
84 ViewPropertyCaster<T>::ToInt64(property->default_value)); | |
85 if (property->deallocator && | |
86 old != ViewPropertyCaster<T>::ToInt64(property->default_value)) { | |
87 (*property->deallocator)(old); | |
88 } | |
89 } | |
90 | |
91 template <typename T> | |
92 T View::GetLocalProperty(const ViewProperty<T>* property) const { | |
93 return ViewPropertyCaster<T>::FromInt64(GetLocalPropertyInternal( | |
94 property, ViewPropertyCaster<T>::ToInt64(property->default_value))); | |
95 } | |
96 | |
97 template <typename T> | |
98 void View::ClearLocalProperty(const ViewProperty<T>* property) { | |
99 SetLocalProperty(property, property->default_value); | |
100 } | |
101 | |
102 } // namespace mojo | |
103 | |
104 // Macros to instantiate the property getter/setter template functions. | |
105 #define DECLARE_EXPORTED_VIEW_PROPERTY_TYPE(EXPORT, T) \ | |
106 template EXPORT void mojo::View::SetLocalProperty( \ | |
107 const mojo::ViewProperty<T>*, T); \ | |
108 template EXPORT T mojo::View::GetLocalProperty(const mojo::ViewProperty<T>*) \ | |
109 const; \ | |
110 template EXPORT void mojo::View::ClearLocalProperty( \ | |
111 const mojo::ViewProperty<T>*); | |
112 #define DECLARE_VIEW_PROPERTY_TYPE(T) DECLARE_EXPORTED_VIEW_PROPERTY_TYPE(, T) | |
113 | |
114 #define DEFINE_VIEW_PROPERTY_KEY(TYPE, NAME, DEFAULT) \ | |
115 COMPILE_ASSERT(sizeof(TYPE) <= sizeof(int64_t), property_type_too_large); \ | |
116 namespace { \ | |
117 const mojo::ViewProperty<TYPE> NAME##_Value = {DEFAULT, #NAME, nullptr}; \ | |
118 } \ | |
119 const mojo::ViewProperty<TYPE>* const NAME = &NAME##_Value; | |
120 | |
121 #define DEFINE_LOCAL_VIEW_PROPERTY_KEY(TYPE, NAME, DEFAULT) \ | |
122 COMPILE_ASSERT(sizeof(TYPE) <= sizeof(int64_t), property_type_too_large); \ | |
123 namespace { \ | |
124 const mojo::ViewProperty<TYPE> NAME##_Value = {DEFAULT, #NAME, nullptr}; \ | |
125 const mojo::ViewProperty<TYPE>* const NAME = &NAME##_Value; \ | |
126 } | |
127 | |
128 #define DEFINE_OWNED_VIEW_PROPERTY_KEY(TYPE, NAME, DEFAULT) \ | |
129 namespace { \ | |
130 void Deallocator##NAME(int64_t p) { \ | |
131 enum { type_must_be_complete = sizeof(TYPE) }; \ | |
132 delete mojo::ViewPropertyCaster<TYPE*>::FromInt64(p); \ | |
133 } \ | |
134 const mojo::ViewProperty<TYPE*> NAME##_Value = {DEFAULT, \ | |
135 #NAME, \ | |
136 &Deallocator##NAME}; \ | |
137 } \ | |
138 const mojo::ViewProperty<TYPE*>* const NAME = &NAME##_Value; | |
139 | |
140 #endif // MOJO_SERVICES_VIEW_MANAGER_PUBLIC_CPP_VIEW_PROPERTY_H_ | |
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