anchovy.utils.flexibleobject.flexibleproperty source code

1 /*
2 Copyright (c) 2013 Andrey Penechko
3 
4 Boost Software License - Version 1.0 - August 17th, 2003
5 
6 Permission is hereby granted, free of charge, to any person or organization
7 obtaining a copy of the software and accompanying documentation covered by
8 this license the "Software" to use, reproduce, display, distribute,
9 execute, and transmit the Software, and to prepare derivative works of the
10 Software, and to permit third-parties to whom the Software is furnished to
11 do so, all subject to the following:
12 
13 The copyright notices in the Software and this entire statement, including
14 the above license grant, this restriction and the following disclaimer,
15 must be included in all copies of the Software, in whole or in part, and
16 all derivative works of the Software, unless such copies or derivative
17 works are solely in the form of machine-executable object code generated by
18 a source language processor.
19 
20 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
21 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
22 FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
23 SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
24 FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
25 ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
26 DEALINGS IN THE SOFTWARE.
27 */
28 
29 module anchovy.utils.flexibleobject.flexibleproperty;
30 
31 import std.variant : Variant;
32 
33 import anchovy.utils.flexibleobject.flexibleobject : FlexibleObject;
34 import anchovy.utils.signal : Signal;
35 
36 abstract class IProperty
37 {
38 	// called when value changes.
39 	alias PropertyChangedSignal = Signal!(FlexibleObject, Variant);
40 	alias PropertyChangingSignal = Signal!(FlexibleObject, Variant*);
41 
42 	Variant value() @property;
43 	Variant value(Variant) @property;
44 
45 	ref PropertyChangedSignal valueChanged() @property;
46 	ref PropertyChangingSignal valueChanging() @property;
47 
48 	alias value this;
49 }
50 
51 // Simple storage property
52 class ValueProperty : IProperty
53 {
54 	this(FlexibleObject owner, Variant value = Variant(null))
55 	{
56 		_value = value;
57 		_owner = owner;
58 	}
59 
60 	this(T)(FlexibleObject owner, T value)
61 	{
62 		_owner = owner;
63 		_value = Variant(value);
64 	}
65 
66 	override Variant value() @property
67 	{
68 		return _value;
69 	}
70 
71 	override Variant value(Variant newValue) @property
72 	{
73 		// Strange error when comparing two variant with Widget[] inside
74 		// object.Error: object.Exception@src\object_.d(107):
75 		// need opCmp for class anchovy.gui.widget.Widget
76 		if (newValue == _value) return _value;
77 
78 		if (_isChanging)
79 		{
80 			return _value;
81 		}
82 
83 		_isChanging = true;
84 
85 		_valueChanging.emit(_owner, &newValue);
86 
87 		if (newValue == _value)
88 		{
89 			_isChanging = false;
90 			return _value;
91 		}
92 		_value = newValue;
93 		_valueChanged.emit(_owner, _value);
94 
95 		_isChanging = false;
96 
97 		return _value;
98 	}
99 
100 	override ref PropertyChangedSignal valueChanged() @property
101 	{
102 		return _valueChanged;
103 	}
104 
105 	override ref PropertyChangingSignal valueChanging() @property
106 	{
107 		return _valueChanging;
108 	}
109 
110 	Variant _value;
111 	PropertyChangedSignal _valueChanged;
112 	PropertyChangingSignal _valueChanging;
113 	FlexibleObject _owner;
114 	bool _isChanging = false;
115 }