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1 // Copyright (c) 2013 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 PPAPI_CPP_EXTENSIONS_EVENT_BASE_H_ | |
6 #define PPAPI_CPP_EXTENSIONS_EVENT_BASE_H_ | |
7 | |
8 #include "ppapi/c/extensions/dev/ppb_ext_events_dev.h" | |
9 #include "ppapi/c/pp_macros.h" | |
10 #include "ppapi/c/pp_stdint.h" | |
11 #include "ppapi/c/pp_var.h" | |
12 #include "ppapi/cpp/extensions/from_var_converter.h" | |
13 #include "ppapi/cpp/instance_handle.h" | |
14 #include "ppapi/cpp/logging.h" | |
15 | |
16 namespace pp { | |
17 namespace ext { | |
18 namespace internal { | |
19 | |
20 // This file contains base classes for events. Usually you don't need to use | |
21 // them directly. | |
22 // | |
23 // For each event type, there is a corresponding event class derived from | |
24 // EventBase[0-3]. The event class defines a Listener interface and exposes the | |
25 // public methods of GenericEventBase. | |
26 // | |
27 // Take pp::ext::alarms::OnAlarmEvent_Dev as example, your code to listen to the | |
28 // event would look like this: | |
29 // | |
30 // class MyListener : public pp::ext::alarms::OnAlarmEvent_Dev { | |
31 // ... | |
32 // // The parameter is a non-const reference so you could directly modify it | |
33 // // if necessary. | |
34 // virtual void OnAlarm(Alarm_Dev& alarm) { | |
35 // ...handle the event... | |
36 // } | |
37 // }; | |
38 // | |
39 // MyListener on_alarm_listener; | |
40 // // The listener is not owned by the event and must outlive it. | |
41 // pp::ext::alarms::OnAlarmEvent_Dev on_alarm(instance, &on_alarm_listener); | |
42 // on_alarm.StartListening(); | |
43 // ... | |
44 // // It is guaranteed that |on_alarm_listener| won't get called after | |
45 // // |on_alarm| goes away. So this step is optional. | |
46 // on_alarm.StopListening(); | |
47 | |
48 class GenericEventBase { | |
49 public: | |
50 bool StartListening(); | |
51 void StopListening(); | |
52 | |
53 bool IsListening() const { return listener_id_ != 0; } | |
54 uint32_t listener_id() const { return listener_id_; } | |
55 | |
56 protected: | |
57 GenericEventBase(const InstanceHandle& instance, | |
58 const PP_Ext_EventListener& pp_listener); | |
59 ~GenericEventBase(); | |
60 | |
61 InstanceHandle instance_; | |
62 uint32_t listener_id_; | |
63 const PP_Ext_EventListener pp_listener_; | |
64 | |
65 private: | |
66 // Disallow copying and assignment. | |
67 GenericEventBase(const GenericEventBase&); | |
68 GenericEventBase& operator=(const GenericEventBase&); | |
69 }; | |
70 | |
71 // EventBase[0-3] are event base classes which can be instantiated with a | |
72 // pointer to a PP_Ext_EventListener creation function and the input parameter | |
73 // types of the listener callback. | |
74 // | |
75 // For example, EvenBase1<PP_Ext_Alarms_OnAlarm_Dev, Alarm_Dev> deals with | |
76 // the event type defined by the PP_Ext_Alarms_OnAlarm_Dev function pointer. And | |
77 // it defines a pure virtual method as the listener callback: | |
78 // virtual void Callback(Alarm_Dev&) = 0; | |
79 | |
80 typedef PP_Ext_EventListener (*CreatePPEventListener0)( | |
81 void (*)(uint32_t, void*), void*); | |
82 template <const CreatePPEventListener0 kCreatePPEventListener0> | |
83 class EventBase0 : public GenericEventBase { | |
84 public: | |
85 explicit EventBase0(const InstanceHandle& instance) | |
86 : PP_ALLOW_THIS_IN_INITIALIZER_LIST( | |
87 GenericEventBase(instance, | |
88 kCreatePPEventListener0(&CallbackThunk, this))) { | |
89 } | |
90 | |
91 virtual ~EventBase0() {} | |
92 | |
93 private: | |
94 virtual void Callback() = 0; | |
95 | |
96 static void CallbackThunk(uint32_t listener_id, void* user_data) { | |
97 EventBase0<kCreatePPEventListener0>* event_base = | |
98 static_cast<EventBase0<kCreatePPEventListener0>*>(user_data); | |
99 PP_DCHECK(listener_id == event_base->listener_id_); | |
100 // Suppress unused variable warnings. | |
101 static_cast<void>(listener_id); | |
102 | |
103 event_base->Callback(); | |
104 } | |
105 | |
106 // Disallow copying and assignment. | |
107 EventBase0(const EventBase0<kCreatePPEventListener0>&); | |
108 EventBase0<kCreatePPEventListener0>& operator=( | |
109 const EventBase0<kCreatePPEventListener0>&); | |
110 }; | |
111 | |
112 typedef PP_Ext_EventListener (*CreatePPEventListener1)( | |
113 void (*)(uint32_t, void*, PP_Var), void*); | |
114 template <const CreatePPEventListener1 kCreatePPEventListener1, class A> | |
115 class EventBase1 : public GenericEventBase { | |
116 public: | |
117 explicit EventBase1(const InstanceHandle& instance) | |
118 : PP_ALLOW_THIS_IN_INITIALIZER_LIST( | |
119 GenericEventBase(instance, | |
120 kCreatePPEventListener1(&CallbackThunk, this))) { | |
121 } | |
122 | |
123 virtual ~EventBase1() {} | |
124 | |
125 private: | |
126 virtual void Callback(A&) = 0; | |
127 | |
128 static void CallbackThunk(uint32_t listener_id, | |
129 void* user_data, | |
130 PP_Var var_a) { | |
131 EventBase1<kCreatePPEventListener1, A>* event_base = | |
132 static_cast<EventBase1<kCreatePPEventListener1, A>*>(user_data); | |
133 PP_DCHECK(listener_id == event_base->listener_id_); | |
134 // Suppress unused variable warnings. | |
135 static_cast<void>(listener_id); | |
136 | |
137 FromVarConverter<A> a(var_a); | |
138 event_base->Callback(a.value()); | |
139 } | |
140 | |
141 // Disallow copying and assignment. | |
142 EventBase1(const EventBase1<kCreatePPEventListener1, A>&); | |
143 EventBase1<kCreatePPEventListener1, A>& operator=( | |
144 const EventBase1<kCreatePPEventListener1, A>&); | |
145 }; | |
146 | |
147 typedef PP_Ext_EventListener (*CreatePPEventListener2)( | |
148 void (*)(uint32_t, void*, PP_Var, PP_Var), void*); | |
149 template <const CreatePPEventListener2 kCreatePPEventListener2, | |
150 class A, | |
151 class B> | |
152 class EventBase2 : public GenericEventBase { | |
153 public: | |
154 explicit EventBase2(const InstanceHandle& instance) | |
155 : PP_ALLOW_THIS_IN_INITIALIZER_LIST( | |
156 GenericEventBase(instance, | |
157 kCreatePPEventListener2(&CallbackThunk, this))) { | |
158 } | |
159 | |
160 virtual ~EventBase2() {} | |
161 | |
162 private: | |
163 virtual void Callback(A&, B&) = 0; | |
164 | |
165 static void CallbackThunk(uint32_t listener_id, | |
166 void* user_data, | |
167 PP_Var var_a, | |
168 PP_Var var_b) { | |
169 EventBase2<kCreatePPEventListener2, A, B>* event_base = | |
170 static_cast<EventBase2<kCreatePPEventListener2, A, B>*>(user_data); | |
171 PP_DCHECK(listener_id == event_base->listener_id_); | |
172 // Suppress unused variable warnings. | |
173 static_cast<void>(listener_id); | |
174 | |
175 FromVarConverter<A> a(var_a); | |
176 FromVarConverter<B> b(var_b); | |
177 event_base->Callback(a.value(), b.value()); | |
178 } | |
179 | |
180 // Disallow copying and assignment. | |
181 EventBase2(const EventBase2<kCreatePPEventListener2, A, B>&); | |
182 EventBase2<kCreatePPEventListener2, A, B>& operator=( | |
183 const EventBase2<kCreatePPEventListener2, A, B>&); | |
184 }; | |
185 | |
186 typedef PP_Ext_EventListener (*CreatePPEventListener3)( | |
187 void (*)(uint32_t, void*, PP_Var, PP_Var, PP_Var), void*); | |
188 template <const CreatePPEventListener3 kCreatePPEventListener3, | |
189 class A, | |
190 class B, | |
191 class C> | |
192 class EventBase3 : public GenericEventBase { | |
193 public: | |
194 explicit EventBase3(const InstanceHandle& instance) | |
195 : PP_ALLOW_THIS_IN_INITIALIZER_LIST( | |
196 GenericEventBase(instance, | |
197 kCreatePPEventListener3(&CallbackThunk, this))) { | |
198 } | |
199 | |
200 virtual ~EventBase3() {} | |
201 | |
202 private: | |
203 virtual void Callback(A&, B&, C&) = 0; | |
204 | |
205 static void CallbackThunk(uint32_t listener_id, | |
206 void* user_data, | |
207 PP_Var var_a, | |
208 PP_Var var_b, | |
209 PP_Var var_c) { | |
210 EventBase3<kCreatePPEventListener3, A, B, C>* event_base = | |
211 static_cast<EventBase3<kCreatePPEventListener3, A, B, C>*>(user_data); | |
212 PP_DCHECK(listener_id == event_base->listener_id_); | |
213 // Suppress unused variable warnings. | |
214 static_cast<void>(listener_id); | |
215 | |
216 FromVarConverter<A> a(var_a); | |
217 FromVarConverter<B> b(var_b); | |
218 FromVarConverter<C> c(var_c); | |
219 event_base->Callback(a.value(), b.value(), c.value()); | |
220 } | |
221 | |
222 // Disallow copying and assignment. | |
223 EventBase3(const EventBase3<kCreatePPEventListener3, A, B, C>&); | |
224 EventBase3<kCreatePPEventListener3, A, B, C>& operator=( | |
225 const EventBase3<kCreatePPEventListener3, A, B, C>&); | |
226 }; | |
227 | |
228 } // namespace internal | |
229 } // namespace ext | |
230 } // namespace pp | |
231 | |
232 #endif // PPAPI_CPP_EXTENSIONS_EVENT_BASE_H_ | |
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