oculus1: cfe4979ab3eb libovr/Src/OVR

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view libovr/Src/OVR_ThreadCommandQueue.h @ 17:cfe4979ab3eb

ops, minor error in the last commit

author	John Tsiombikas <nuclear@member.fsf.org>
date	Sat, 21 Sep 2013 07:09:48 +0300
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1 /************************************************************************************

3 PublicHeader: None

4 Filename : OVR_ThreadCommandQueue.h

5 Content : Command queue for operations executed on a thread

6 Created : October 29, 2012

7 Author : Michael Antonov

11 Use of this software is subject to the terms of the Oculus license

12 agreement provided at the time of installation or download, or which

13 otherwise accompanies this software in either electronic or hard copy form.

15 ************************************************************************************/

17 #ifndef OVR_ThreadCommandQueue_h

18 #define OVR_ThreadCommandQueue_h

20 #include "Kernel/OVR_Types.h"

21 #include "Kernel/OVR_List.h"

22 #include "Kernel/OVR_Atomic.h"

23 #include "Kernel/OVR_Threads.h"

25 namespace OVR {

27 class ThreadCommand;

28 class ThreadCommandQueue;

31 //-------------------------------------------------------------------------------------

32 // ***** ThreadCommand

34 // ThreadCommand is a base class implementation for commands stored in ThreadCommandQueue.

35 class ThreadCommand

36 {

37 public:

39 // NotifyEvent is used by ThreadCommandQueue::PushCallAndWait to notify the

40 // calling (producer) thread when command is completed or queue slot is available.

41 class NotifyEvent : public ListNode<NotifyEvent>, public NewOverrideBase

42 {

43 Event E;

44 public:

45 NotifyEvent() { }

47 void Wait() { E.Wait(); }

48 void PulseEvent() { E.PulseEvent(); }

49 };

51 // ThreadCommand::PopBuffer is temporary storage for a command popped off

52 // by ThreadCommandQueue::PopCommand.

53 class PopBuffer

54 {

55 enum { MaxSize = 256 };

57 UPInt Size;

58 union {

59 UByte Buffer[MaxSize];

60 UPInt Align;

61 };

63 ThreadCommand* toCommand() const { return (ThreadCommand*)Buffer; }

65 public:

66 PopBuffer() : Size(0) { }

67 ~PopBuffer();

69 void InitFromBuffer(void* data);

71 bool HasCommand() const { return Size != 0; }

72 UPInt GetSize() const { return Size; }

73 bool NeedsWait() const { return toCommand()->NeedsWait(); }

74 NotifyEvent* GetEvent() const { return toCommand()->pEvent; }

76 // Execute the command and also notifies caller to finish waiting,

77 // if necessary.

78 void Execute();

79 };

81 UInt16 Size;

82 bool WaitFlag;

83 bool ExitFlag; // Marks the last exit command.

84 NotifyEvent* pEvent;

86 ThreadCommand(UPInt size, bool waitFlag, bool exitFlag = false)

87 : Size((UInt16)size), WaitFlag(waitFlag), ExitFlag(exitFlag), pEvent(0) { }

88 virtual ~ThreadCommand() { }

90 bool NeedsWait() const { return WaitFlag; }

91 UPInt GetSize() const { return Size; }

93 virtual void Execute() const = 0;

94 // Copy constructor used for serializing this to memory buffer.

95 virtual ThreadCommand* CopyConstruct(void* p) const = 0;

96 };

99 //-------------------------------------------------------------------------------------

100

101 // CleanType is a template that strips 'const' and '&' modifiers from the argument type;

102 // for example, typename CleanType<A&>::Type is equivalent to A.

103 template<class T> struct CleanType { typedef T Type; };

104 template<class T> struct CleanType<T&> { typedef T Type; };

105 template<class T> struct CleanType<const T> { typedef T Type; };

106 template<class T> struct CleanType<const T&> { typedef T Type; };

107

108 // SelfType is a template that yields the argument type. This helps avoid conflicts with

109 // automatic template argument deduction for function calls when identical argument

110 // is already defined.

111 template<class T> struct SelfType { typedef T Type; };

112

113

114

115 //-------------------------------------------------------------------------------------

116 // ThreadCommand specializations for member functions with different number of

117 // arguments and argument types.

118

119 // Used to return nothing from a ThreadCommand, to avoid problems with 'void'.

120 struct Void

121 {

122 Void() {}

123 Void(int) {}

124 };

125

126 // ThreadCommand for member function with 0 arguments.

127 template<class C, class R>

128 class ThreadCommandMF0 : public ThreadCommand

129 {

130 typedef R (C::*FnPtr)();

131 C* pClass;

132 FnPtr pFn;

133 R* pRet;

134

135 void executeImpl() const

136 {

137 pRet ? (void)(*pRet = (pClass->*pFn)()) :

138 (void)(pClass->*pFn)();

139 }

140

141 public:

142 ThreadCommandMF0(C* pclass, FnPtr fn, R* ret, bool needsWait)

143 : ThreadCommand(sizeof(ThreadCommandMF0), needsWait),

144 pClass(pclass), pFn(fn), pRet(ret) { }

145

146 virtual void Execute() const { executeImpl(); }

147 virtual ThreadCommand* CopyConstruct(void* p) const

148 { return Construct<ThreadCommandMF0>(p, *this); }

149 };

150

151

152 // ThreadCommand for member function with 1 argument.

153 template<class C, class R, class A0>

154 class ThreadCommandMF1 : public ThreadCommand

155 {

156 typedef R (C::*FnPtr)(A0);

157 C* pClass;

158 FnPtr pFn;

159 R* pRet;

160 typename CleanType<A0>::Type AVal0;

161

162 void executeImpl() const

163 {

164 pRet ? (void)(*pRet = (pClass->*pFn)(AVal0)) :

165 (void)(pClass->*pFn)(AVal0);

166 }

167

168 public:

169 ThreadCommandMF1(C* pclass, FnPtr fn, R* ret, A0 a0, bool needsWait)

170 : ThreadCommand(sizeof(ThreadCommandMF1), needsWait),

171 pClass(pclass), pFn(fn), pRet(ret), AVal0(a0) { }

172

173 virtual void Execute() const { executeImpl(); }

174 virtual ThreadCommand* CopyConstruct(void* p) const

175 { return Construct<ThreadCommandMF1>(p, *this); }

176 };

177

178 // ThreadCommand for member function with 2 arguments.

179 template<class C, class R, class A0, class A1>

180 class ThreadCommandMF2 : public ThreadCommand

181 {

182 typedef R (C::*FnPtr)(A0, A1);

183 C* pClass;

184 FnPtr pFn;

185 R* pRet;

186 typename CleanType<A0>::Type AVal0;

187 typename CleanType<A1>::Type AVal1;

188

189 void executeImpl() const

190 {

191 pRet ? (void)(*pRet = (pClass->*pFn)(AVal0, AVal1)) :

192 (void)(pClass->*pFn)(AVal0, AVal1);

193 }

194

195 public:

196 ThreadCommandMF2(C* pclass, FnPtr fn, R* ret, A0 a0, A1 a1, bool needsWait)

197 : ThreadCommand(sizeof(ThreadCommandMF2), needsWait),

198 pClass(pclass), pFn(fn), pRet(ret), AVal0(a0), AVal1(a1) { }

199

200 virtual void Execute() const { executeImpl(); }

201 virtual ThreadCommand* CopyConstruct(void* p) const

202 { return Construct<ThreadCommandMF2>(p, *this); }

203 };

204

205

206 //-------------------------------------------------------------------------------------

207 // ***** ThreadCommandQueue

208

209 // ThreadCommandQueue is a queue of executable function-call commands intended to be

210 // serviced by a single consumer thread. Commands are added to the queue with PushCall

211 // and removed with PopCall; they are processed in FIFO order. Multiple producer threads

212 // are supported and will be blocked if internal data buffer is full.

213

214 class ThreadCommandQueue

215 {

216 public:

217

218 ThreadCommandQueue();

219 virtual ~ThreadCommandQueue();

220

221

222 // Pops the next command from the thread queue, if any is available.

223 // The command should be executed by calling popBuffer->Execute().

224 // Returns 'false' if no command is available at the time of the call.

225 bool PopCommand(ThreadCommand::PopBuffer* popBuffer);

226

227 // Generic implementaion of PushCommand; enqueues a command for execution.

228 // Returns 'false' if push failed, usually indicating thread shutdown.

229 bool PushCommand(const ThreadCommand& command);

230

231 //

232 void PushExitCommand(bool wait);

233

234 // Returns 'true' once ExitCommand has been processed, so the thread can shut down.

235 bool IsExiting() const;

236

237

238 // These two virtual functions serve as notifications for derived

239 // thread waiting.

240 virtual void OnPushNonEmpty_Locked() { }

241 virtual void OnPopEmpty_Locked() { }

242

243

244 // *** PushCall with no result

245

246 // Enqueue a member function of 'this' class to be called on consumer thread.

247 // By default the function returns immediately; set 'wait' argument to 'true' to

248 // wait for completion.

249 template<class C, class R>

250 bool PushCall(R (C::*fn)(), bool wait = false)

251 { return PushCommand(ThreadCommandMF0<C,R>(static_cast<C*>(this), fn, 0, wait)); }

252 template<class C, class R, class A0>

253 bool PushCall(R (C::*fn)(A0), typename SelfType<A0>::Type a0, bool wait = false)

254 { return PushCommand(ThreadCommandMF1<C,R,A0>(static_cast<C*>(this), fn, 0, a0, wait)); }

255 template<class C, class R, class A0, class A1>

256 bool PushCall(R (C::*fn)(A0, A1),

257 typename SelfType<A0>::Type a0, typename SelfType<A1>::Type a1, bool wait = false)

258 { return PushCommand(ThreadCommandMF2<C,R,A0,A1>(static_cast<C*>(this), fn, 0, a0, a1, wait)); }

259 // Enqueue a specified member function call of class C.

260 // By default the function returns immediately; set 'wait' argument to 'true' to

261 // wait for completion.

262 template<class C, class R>

263 bool PushCall(C* p, R (C::*fn)(), bool wait = false)

264 { return PushCommand(ThreadCommandMF0<C,R>(p, fn, 0, wait)); }

265 template<class C, class R, class A0>

266 bool PushCall(C* p, R (C::*fn)(A0), typename SelfType<A0>::Type a0, bool wait = false)

267 { return PushCommand(ThreadCommandMF1<C,R,A0>(p, fn, 0, a0, wait)); }

268 template<class C, class R, class A0, class A1>

269 bool PushCall(C* p, R (C::*fn)(A0, A1),

270 typename SelfType<A0>::Type a0, typename SelfType<A1>::Type a1, bool wait = false)

271 { return PushCommand(ThreadCommandMF2<C,R,A0,A1>(p, fn, 0, a0, a1, wait)); }

272

273

274 // *** PushCall with Result

275

276 // Enqueue a member function of 'this' class call and wait for call to complete

277 // on consumer thread before returning.

278 template<class C, class R>

279 bool PushCallAndWaitResult(R (C::*fn)(), R* ret)

280 { return PushCommand(ThreadCommandMF0<C,R>(static_cast<C*>(this), fn, ret, true)); }

281 template<class C, class R, class A0>

282 bool PushCallAndWaitResult(R (C::*fn)(A0), R* ret, typename SelfType<A0>::Type a0)

283 { return PushCommand(ThreadCommandMF1<C,R,A0>(static_cast<C*>(this), fn, ret, a0, true)); }

284 template<class C, class R, class A0, class A1>

285 bool PushCallAndWaitResult(R (C::*fn)(A0, A1), R* ret,

286 typename SelfType<A0>::Type a0, typename SelfType<A1>::Type a1)

287 { return PushCommand(ThreadCommandMF2<C,R,A0,A1>(static_cast<C*>(this), fn, ret, a0, a1, true)); }

288 // Enqueue a member function call for class C and wait for the call to complete

289 // on consumer thread before returning.

290 template<class C, class R>

291 bool PushCallAndWaitResult(C* p, R (C::*fn)(), R* ret)

292 { return PushCommand(ThreadCommandMF0<C,R>(p, fn, ret, true)); }

293 template<class C, class R, class A0>

294 bool PushCallAndWaitResult(C* p, R (C::*fn)(A0), R* ret, typename SelfType<A0>::Type a0)

295 { return PushCommand(ThreadCommandMF1<C,R,A0>(p, fn, ret, a0, true)); }

296 template<class C, class R, class A0, class A1>

297 bool PushCallAndWaitResult(C* p, R (C::*fn)(A0, A1), R* ret,

298 typename SelfType<A0>::Type a0, typename SelfType<A1>::Type a1)

299 { return PushCommand(ThreadCommandMF2<C,R,A0,A1>(p, fn, ret, a0, a1, true)); }

300

301 private:

302 class ThreadCommandQueueImpl* pImpl;

303 };

304

305

306 }

307

308 #endif // OVR_ThreadCommandQueue_h