先看看定义该类的头文件——CCRef.h
1 /****************************************************************************
2 Copyright (c) 2010-2012 cocos2d-x.org
3 Copyright (c) 2013-2014 Chukong Technologies
4
5 http://www.cocos2d-x.org
6
7 Permission is hereby granted, free of charge, to any person obtaining a copy
8 of this software and associated documentation files (the "Software"), to deal
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12 furnished to do so, subject to the following conditions:
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14 The above copyright notice and this permission notice shall be included in
15 all copies or substantial portions of the Software.
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18 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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25
26 #ifndef __CCREF_H__
27 #define __CCREF_H__
28
29 #include "CCPlatformMacros.h"
30 #include "ccConfig.h"
31
32 NS_CC_BEGIN
33
34 /**
35 * @addtogroup base_nodes
36 * @{
37 */
38
39 class Ref;
40
41 /** Interface that defines how to clone an Ref */
42 class CC_DLL Clonable
43 {
44 public:
45 /** returns a copy of the Ref */
46 virtual Clonable* clone() const = 0;
47 /**
48 * @js NA
49 * @lua NA
50 */
51 virtual ~Clonable() {};
52
53 /** returns a copy of the Ref.
54 @deprecated Use clone() instead
55 */
56 CC_DEPRECATED_ATTRIBUTE Ref* copy() const
57 {
58 // use "clone" instead
59 CC_ASSERT(false);
60 return nullptr;
61 }
62 };
63
64 class CC_DLL Ref
65 {
66 public:
67 /**
68 * Retains the ownership.
69 *
70 * This increases the Ref‘s reference count.
71 *
72 * @see release, autorelease
73 * @js NA
74 */
75 void retain();
76
77 /**
78 * Release the ownership immediately.
79 *
80 * This decrements the Ref‘s reference count.
81 *
82 * If the reference count reaches 0 after the descrement, this Ref is
83 * destructed.
84 *
85 * @see retain, autorelease
86 * @js NA
87 */
88 void release();
89
90 /**
91 * Release the ownership sometime soon automatically.
92 *
93 * This descrements the Ref‘s reference count at the end of current
94 * autorelease pool block.
95 *
96 * If the reference count reaches 0 after the descrement, this Ref is
97 * destructed.
98 *
99 * @returns The Ref itself.
100 *
101 * @see AutoreleasePool, retain, release
102 * @js NA
103 * @lua NA
104 */
105 Ref* autorelease();
106
107 /**
108 * Returns the Ref‘s current reference count.
109 *
110 * @returns The Ref‘s reference count.
111 * @js NA
112 */
113 unsigned int getReferenceCount() const;
114
115 protected:
116 /**
117 * Constructor
118 *
119 * The Ref‘s reference count is 1 after construction.
120 * @js NA
121 */
122 Ref();
123
124 public:
125 /**
126 * @js NA
127 * @lua NA
128 */
129 virtual ~Ref();
130
131 protected:
132 /// count of references
133 unsigned int _referenceCount;
134
135 friend class AutoreleasePool;
136
137 #if CC_ENABLE_SCRIPT_BINDING
138 public:
139 /// object id, ScriptSupport need public _ID
140 unsigned int _ID;
141 /// Lua reference id
142 int _luaID;
143 #endif
144 };
145
146 class Node;
147
148 typedef void (Ref::*SEL_CallFunc)();
149 typedef void (Ref::*SEL_CallFuncN)(Node*);
150 typedef void (Ref::*SEL_CallFuncND)(Node*, void*);
151 typedef void (Ref::*SEL_CallFuncO)(Ref*);
152 typedef void (Ref::*SEL_MenuHandler)(Ref*);
153 typedef void (Ref::*SEL_SCHEDULE)(float);
154
155 #define callfunc_selector(_SELECTOR) static_cast<cocos2d::SEL_CallFunc>(&_SELECTOR)
156 #define callfuncN_selector(_SELECTOR) static_cast<cocos2d::SEL_CallFuncN>(&_SELECTOR)
157 #define callfuncND_selector(_SELECTOR) static_cast<cocos2d::SEL_CallFuncND>(&_SELECTOR)
158 #define callfuncO_selector(_SELECTOR) static_cast<cocos2d::SEL_CallFuncO>(&_SELECTOR)
159 #define menu_selector(_SELECTOR) static_cast<cocos2d::SEL_MenuHandler>(&_SELECTOR)
160 #define schedule_selector(_SELECTOR) static_cast<cocos2d::SEL_SCHEDULE>(&_SELECTOR)
161
162 // end of base_nodes group
163 /// @}
164
165 NS_CC_END
166
167 #endif // __CCREF_H__
CCRef.h
头文件中主要有以下内容：
1、Clonable接口的定义；
2、Ref类的定义；
3、六个回调函数宏定义（包括相应类型定义）；
Clonable接口成员如下：
由接口的名称含义就可以知道，该接口的主要作用就是克隆Ref类的成员，由于该头文件之前还未有Ref类的定义，而接口函数中有使用了Ref，所以又一个Ref类的前向引用（C++好像有这么个概念）
clone()和copy()均可以完成Ref对象的克隆，不过新版本中copy()已经废弃，建议使用clone();
Ref类的函数成员如下：
retain()；每调用一次引用次数+1；
release()；每调用一次引用次数-1；
getReferenceCount()；获取引用的次数；
autorelease()；每调用一次autorelease pool 中的Ref引用数-1；
Ref类的数据成员中，有一个无符号整型成员 _referenceCount，用来记录引用次数的；
值得注意的是Ref类还有一个友元类AutoreleasePool；
回调函数及相应类型定义
typedef void (Ref::*SEL_CallFunc)(); //
typedef void (Ref::*SEL_CallFuncN)(Node*);
typedef void (Ref::*SEL_CallFuncND)(Node*, void*);
typedef void (Ref::*SEL_CallFuncO)(Ref*);
typedef void (Ref::*SEL_MenuHandler)(Ref*);
typedef void (Ref::*SEL_SCHEDULE)(float);#define callfunc_selector(_SELECTOR) static_cast<cocos2d::SEL_CallFunc>(&_SELECTOR)
#define callfuncN_selector(_SELECTOR) static_cast<cocos2d::SEL_CallFuncN>(&_SELECTOR)
#define callfuncND_selector(_SELECTOR) static_cast<cocos2d::SEL_CallFuncND>(&_SELECTOR)
#define callfuncO_selector(_SELECTOR) static_cast<cocos2d::SEL_CallFuncO>(&_SELECTOR)
#define menu_selector(_SELECTOR) static_cast<cocos2d::SEL_MenuHandler>(&_SELECTOR)
#define schedule_selector(_SELECTOR) static_cast<cocos2d::SEL_SCHEDULE>(&_SELECTOR)
关于回调函数宏定义及类型定义，下篇中会详细说明，因为引擎中涉及到太多太多，而且还不是很好理解。
Cocos2d-X学习之Ref类
时间： 2024-08-25 18:01:03