1 | // |
2 | // ActiveResult.h |
3 | // |
4 | // Library: Foundation |
5 | // Package: Threading |
6 | // Module: ActiveObjects |
7 | // |
8 | // Definition of the ActiveResult class. |
9 | // |
10 | // Copyright (c) 2004-2007, Applied Informatics Software Engineering GmbH. |
11 | // and Contributors. |
12 | // |
13 | // SPDX-License-Identifier: BSL-1.0 |
14 | // |
15 | |
16 | |
17 | #ifndef Foundation_ActiveResult_INCLUDED |
18 | #define Foundation_ActiveResult_INCLUDED |
19 | |
20 | |
21 | #include "Poco/Foundation.h" |
22 | #include "Poco/Mutex.h" |
23 | #include "Poco/Event.h" |
24 | #include "Poco/RefCountedObject.h" |
25 | #include "Poco/Exception.h" |
26 | #include <algorithm> |
27 | |
28 | |
29 | namespace Poco { |
30 | |
31 | |
32 | template <class ResultType> |
33 | class ActiveResultHolder: public RefCountedObject |
34 | /// This class holds the result of an asynchronous method |
35 | /// invocation. It is used to pass the result from the |
36 | /// execution thread back to the invocation thread. |
37 | /// The class uses reference counting for memory management. |
38 | /// Do not use this class directly, use ActiveResult instead. |
39 | { |
40 | public: |
41 | ActiveResultHolder(): |
42 | _pData(0), |
43 | _pExc(0), |
44 | _event(Event::EVENT_MANUALRESET) |
45 | /// Creates an ActiveResultHolder. |
46 | { |
47 | } |
48 | |
49 | ResultType& data() |
50 | /// Returns a reference to the actual result. |
51 | { |
52 | poco_check_ptr(_pData); |
53 | return *_pData; |
54 | } |
55 | |
56 | void data(ResultType* pData) |
57 | { |
58 | delete _pData; |
59 | _pData = pData; |
60 | } |
61 | |
62 | void wait() |
63 | /// Pauses the caller until the result becomes available. |
64 | { |
65 | _event.wait(); |
66 | } |
67 | |
68 | bool tryWait(long milliseconds) |
69 | /// Waits up to the specified interval for the result to |
70 | /// become available. Returns true if the result became |
71 | /// available, false otherwise. |
72 | { |
73 | return _event.tryWait(milliseconds); |
74 | } |
75 | |
76 | void wait(long milliseconds) |
77 | /// Waits up to the specified interval for the result to |
78 | /// become available. Throws a TimeoutException if the |
79 | /// result did not became available. |
80 | { |
81 | _event.wait(milliseconds); |
82 | } |
83 | |
84 | void notify() |
85 | /// Notifies the invoking thread that the result became available. |
86 | { |
87 | _event.set(); |
88 | } |
89 | |
90 | bool failed() const |
91 | /// Returns true if the active method failed (and threw an exception). |
92 | /// Information about the exception can be obtained by calling error(). |
93 | { |
94 | return _pExc != 0; |
95 | } |
96 | |
97 | std::string error() const |
98 | /// If the active method threw an exception, a textual representation |
99 | /// of the exception is returned. An empty string is returned if the |
100 | /// active method completed successfully. |
101 | { |
102 | if (_pExc) |
103 | return _pExc->message(); |
104 | else |
105 | return std::string(); |
106 | } |
107 | |
108 | Exception* exception() const |
109 | /// If the active method threw an exception, a clone of the exception |
110 | /// object is returned, otherwise null. |
111 | { |
112 | return _pExc; |
113 | } |
114 | |
115 | void error(const Exception& exc) |
116 | /// Sets the exception. |
117 | { |
118 | delete _pExc; |
119 | _pExc = exc.clone(); |
120 | } |
121 | |
122 | void error(const std::string& msg) |
123 | /// Sets the exception. |
124 | { |
125 | delete _pExc; |
126 | _pExc = new UnhandledException(msg); |
127 | } |
128 | |
129 | protected: |
130 | ~ActiveResultHolder() |
131 | { |
132 | delete _pData; |
133 | delete _pExc; |
134 | } |
135 | |
136 | private: |
137 | ResultType* _pData; |
138 | Exception* _pExc; |
139 | Event _event; |
140 | }; |
141 | |
142 | |
143 | |
144 | template <> |
145 | class ActiveResultHolder<void>: public RefCountedObject |
146 | { |
147 | public: |
148 | ActiveResultHolder(): |
149 | _pExc(0), |
150 | _event(Event::EVENT_MANUALRESET) |
151 | /// Creates an ActiveResultHolder. |
152 | { |
153 | } |
154 | |
155 | void wait() |
156 | /// Pauses the caller until the result becomes available. |
157 | { |
158 | _event.wait(); |
159 | } |
160 | |
161 | bool tryWait(long milliseconds) |
162 | /// Waits up to the specified interval for the result to |
163 | /// become available. Returns true if the result became |
164 | /// available, false otherwise. |
165 | { |
166 | return _event.tryWait(milliseconds); |
167 | } |
168 | |
169 | void wait(long milliseconds) |
170 | /// Waits up to the specified interval for the result to |
171 | /// become available. Throws a TimeoutException if the |
172 | /// result did not became available. |
173 | { |
174 | _event.wait(milliseconds); |
175 | } |
176 | |
177 | void notify() |
178 | /// Notifies the invoking thread that the result became available. |
179 | { |
180 | _event.set(); |
181 | } |
182 | |
183 | bool failed() const |
184 | /// Returns true if the active method failed (and threw an exception). |
185 | /// Information about the exception can be obtained by calling error(). |
186 | { |
187 | return _pExc != 0; |
188 | } |
189 | |
190 | std::string error() const |
191 | /// If the active method threw an exception, a textual representation |
192 | /// of the exception is returned. An empty string is returned if the |
193 | /// active method completed successfully. |
194 | { |
195 | if (_pExc) |
196 | return _pExc->message(); |
197 | else |
198 | return std::string(); |
199 | } |
200 | |
201 | Exception* exception() const |
202 | /// If the active method threw an exception, a clone of the exception |
203 | /// object is returned, otherwise null. |
204 | { |
205 | return _pExc; |
206 | } |
207 | |
208 | void error(const Exception& exc) |
209 | /// Sets the exception. |
210 | { |
211 | delete _pExc; |
212 | _pExc = exc.clone(); |
213 | } |
214 | |
215 | void error(const std::string& msg) |
216 | /// Sets the exception. |
217 | { |
218 | delete _pExc; |
219 | _pExc = new UnhandledException(msg); |
220 | } |
221 | |
222 | protected: |
223 | ~ActiveResultHolder() |
224 | { |
225 | delete _pExc; |
226 | } |
227 | |
228 | private: |
229 | Exception* _pExc; |
230 | Event _event; |
231 | }; |
232 | |
233 | |
234 | template <class RT> |
235 | class ActiveResult |
236 | /// This class holds the result of an asynchronous method |
237 | /// invocation (see class ActiveMethod). It is used to pass the |
238 | /// result from the execution thread back to the invocation thread. |
239 | { |
240 | public: |
241 | typedef RT ResultType; |
242 | typedef ActiveResultHolder<ResultType> ActiveResultHolderType; |
243 | |
244 | ActiveResult(ActiveResultHolderType* pHolder): |
245 | _pHolder(pHolder) |
246 | /// Creates the active result. For internal use only. |
247 | { |
248 | poco_check_ptr (pHolder); |
249 | } |
250 | |
251 | ActiveResult(const ActiveResult& result) |
252 | /// Copy constructor. |
253 | { |
254 | _pHolder = result._pHolder; |
255 | _pHolder->duplicate(); |
256 | } |
257 | |
258 | ~ActiveResult() |
259 | /// Destroys the result. |
260 | { |
261 | _pHolder->release(); |
262 | } |
263 | |
264 | ActiveResult& operator = (const ActiveResult& result) |
265 | /// Assignment operator. |
266 | { |
267 | ActiveResult tmp(result); |
268 | swap(tmp); |
269 | return *this; |
270 | } |
271 | |
272 | void swap(ActiveResult& result) |
273 | { |
274 | using std::swap; |
275 | swap(_pHolder, result._pHolder); |
276 | } |
277 | |
278 | ResultType& data() const |
279 | /// Returns a reference to the result data. |
280 | { |
281 | return _pHolder->data(); |
282 | } |
283 | |
284 | void data(ResultType* pValue) |
285 | { |
286 | _pHolder->data(pValue); |
287 | } |
288 | |
289 | void wait() |
290 | /// Pauses the caller until the result becomes available. |
291 | { |
292 | _pHolder->wait(); |
293 | } |
294 | |
295 | bool tryWait(long milliseconds) |
296 | /// Waits up to the specified interval for the result to |
297 | /// become available. Returns true if the result became |
298 | /// available, false otherwise. |
299 | { |
300 | return _pHolder->tryWait(milliseconds); |
301 | } |
302 | |
303 | void wait(long milliseconds) |
304 | /// Waits up to the specified interval for the result to |
305 | /// become available. Throws a TimeoutException if the |
306 | /// result did not became available. |
307 | { |
308 | _pHolder->wait(milliseconds); |
309 | } |
310 | |
311 | bool available() const |
312 | /// Returns true if a result is available. |
313 | { |
314 | return _pHolder->tryWait(0); |
315 | } |
316 | |
317 | bool failed() const |
318 | /// Returns true if the active method failed (and threw an exception). |
319 | /// Information about the exception can be obtained by calling error(). |
320 | { |
321 | return _pHolder->failed(); |
322 | } |
323 | |
324 | std::string error() const |
325 | /// If the active method threw an exception, a textual representation |
326 | /// of the exception is returned. An empty string is returned if the |
327 | /// active method completed successfully. |
328 | { |
329 | return _pHolder->error(); |
330 | } |
331 | |
332 | Exception* exception() const |
333 | /// If the active method threw an exception, a clone of the exception |
334 | /// object is returned, otherwise null. |
335 | { |
336 | return _pHolder->exception(); |
337 | } |
338 | |
339 | void notify() |
340 | /// Notifies the invoking thread that the result became available. |
341 | /// For internal use only. |
342 | { |
343 | _pHolder->notify(); |
344 | } |
345 | |
346 | ResultType& data() |
347 | /// Returns a non-const reference to the result data. For internal |
348 | /// use only. |
349 | { |
350 | return _pHolder->data(); |
351 | } |
352 | |
353 | void error(const std::string& msg) |
354 | /// Sets the failed flag and the exception message. |
355 | { |
356 | _pHolder->error(msg); |
357 | } |
358 | |
359 | void error(const Exception& exc) |
360 | /// Sets the failed flag and the exception message. |
361 | { |
362 | _pHolder->error(exc); |
363 | } |
364 | |
365 | private: |
366 | ActiveResult(); |
367 | |
368 | ActiveResultHolderType* _pHolder; |
369 | }; |
370 | |
371 | |
372 | |
373 | template <> |
374 | class ActiveResult<void> |
375 | /// This class holds the result of an asynchronous method |
376 | /// invocation (see class ActiveMethod). It is used to pass the |
377 | /// result from the execution thread back to the invocation thread. |
378 | { |
379 | public: |
380 | typedef ActiveResultHolder<void> ActiveResultHolderType; |
381 | |
382 | ActiveResult(ActiveResultHolderType* pHolder): |
383 | _pHolder(pHolder) |
384 | /// Creates the active result. For internal use only. |
385 | { |
386 | poco_check_ptr (pHolder); |
387 | } |
388 | |
389 | ActiveResult(const ActiveResult& result) |
390 | /// Copy constructor. |
391 | { |
392 | _pHolder = result._pHolder; |
393 | _pHolder->duplicate(); |
394 | } |
395 | |
396 | ~ActiveResult() |
397 | /// Destroys the result. |
398 | { |
399 | _pHolder->release(); |
400 | } |
401 | |
402 | ActiveResult& operator = (const ActiveResult& result) |
403 | /// Assignment operator. |
404 | { |
405 | ActiveResult tmp(result); |
406 | swap(tmp); |
407 | return *this; |
408 | } |
409 | |
410 | void swap(ActiveResult& result) |
411 | { |
412 | using std::swap; |
413 | swap(_pHolder, result._pHolder); |
414 | } |
415 | |
416 | void wait() |
417 | /// Pauses the caller until the result becomes available. |
418 | { |
419 | _pHolder->wait(); |
420 | } |
421 | |
422 | bool tryWait(long milliseconds) |
423 | /// Waits up to the specified interval for the result to |
424 | /// become available. Returns true if the result became |
425 | /// available, false otherwise. |
426 | { |
427 | return _pHolder->tryWait(milliseconds); |
428 | } |
429 | |
430 | void wait(long milliseconds) |
431 | /// Waits up to the specified interval for the result to |
432 | /// become available. Throws a TimeoutException if the |
433 | /// result did not became available. |
434 | { |
435 | _pHolder->wait(milliseconds); |
436 | } |
437 | |
438 | bool available() const |
439 | /// Returns true if a result is available. |
440 | { |
441 | return _pHolder->tryWait(0); |
442 | } |
443 | |
444 | bool failed() const |
445 | /// Returns true if the active method failed (and threw an exception). |
446 | /// Information about the exception can be obtained by calling error(). |
447 | { |
448 | return _pHolder->failed(); |
449 | } |
450 | |
451 | std::string error() const |
452 | /// If the active method threw an exception, a textual representation |
453 | /// of the exception is returned. An empty string is returned if the |
454 | /// active method completed successfully. |
455 | { |
456 | return _pHolder->error(); |
457 | } |
458 | |
459 | Exception* exception() const |
460 | /// If the active method threw an exception, a clone of the exception |
461 | /// object is returned, otherwise null. |
462 | { |
463 | return _pHolder->exception(); |
464 | } |
465 | |
466 | void notify() |
467 | /// Notifies the invoking thread that the result became available. |
468 | /// For internal use only. |
469 | { |
470 | _pHolder->notify(); |
471 | } |
472 | |
473 | void error(const std::string& msg) |
474 | /// Sets the failed flag and the exception message. |
475 | { |
476 | _pHolder->error(msg); |
477 | } |
478 | |
479 | void error(const Exception& exc) |
480 | /// Sets the failed flag and the exception message. |
481 | { |
482 | _pHolder->error(exc); |
483 | } |
484 | |
485 | private: |
486 | ActiveResult(); |
487 | |
488 | ActiveResultHolderType* _pHolder; |
489 | }; |
490 | |
491 | |
492 | } // namespace Poco |
493 | |
494 | |
495 | #endif // Foundation_ActiveResult_INCLUDED |
496 | |