runextensions.h 21.3 KB
Newer Older
hjk's avatar
hjk committed
1
/****************************************************************************
con's avatar
con committed
2
**
Eike Ziller's avatar
Eike Ziller committed
3
4
** Copyright (C) 2015 The Qt Company Ltd.
** Contact: http://www.qt.io/licensing
con's avatar
con committed
5
**
hjk's avatar
hjk committed
6
** This file is part of Qt Creator.
con's avatar
con committed
7
**
hjk's avatar
hjk committed
8
9
10
11
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
Eike Ziller's avatar
Eike Ziller committed
12
13
** a written agreement between you and The Qt Company.  For licensing terms and
** conditions see http://www.qt.io/terms-conditions.  For further information
Eike Ziller's avatar
Eike Ziller committed
14
** use the contact form at http://www.qt.io/contact-us.
15
**
16
** GNU Lesser General Public License Usage
hjk's avatar
hjk committed
17
** Alternatively, this file may be used under the terms of the GNU Lesser
Eike Ziller's avatar
Eike Ziller committed
18
19
20
21
22
23
** General Public License version 2.1 or version 3 as published by the Free
** Software Foundation and appearing in the file LICENSE.LGPLv21 and
** LICENSE.LGPLv3 included in the packaging of this file.  Please review the
** following information to ensure the GNU Lesser General Public License
** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
24
**
Eike Ziller's avatar
Eike Ziller committed
25
26
** In addition, as a special exception, The Qt Company gives you certain additional
** rights.  These rights are described in The Qt Company LGPL Exception
con's avatar
con committed
27
28
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
hjk's avatar
hjk committed
29
****************************************************************************/
hjk's avatar
hjk committed
30

31
32
#ifndef RUNEXTENSIONS_H
#define RUNEXTENSIONS_H
con's avatar
con committed
33

34
35
#include "qtcassert.h"

con's avatar
con committed
36
#include <qrunnable.h>
37
#include <qfuture.h>
con's avatar
con committed
38
39
40
#include <qfutureinterface.h>
#include <qthreadpool.h>

41
#include <chrono>
42
#include <functional>
43
44
45
#include <future>
#include <thread>
#include <vector>
46

con's avatar
con committed
47
48
49
50
51
52
53
54
QT_BEGIN_NAMESPACE

namespace QtConcurrent {

template <typename T,  typename FunctionPointer>
class StoredInterfaceFunctionCall0 : public QRunnable
{
public:
55
    StoredInterfaceFunctionCall0(const FunctionPointer &fn)
con's avatar
con committed
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
    : fn(fn) { }

    QFuture<T> start()
    {
        futureInterface.reportStarted();
        QFuture<T> future = futureInterface.future();
        QThreadPool::globalInstance()->start(this);
        return future;
    }

    void run()
    {
        fn(futureInterface);
        futureInterface.reportFinished();
    }
private:
    QFutureInterface<T> futureInterface;
    FunctionPointer fn;

};
template <typename T,  typename FunctionPointer, typename Class>
class StoredInterfaceMemberFunctionCall0 : public QRunnable
{
public:
    StoredInterfaceMemberFunctionCall0(void (Class::*fn)(QFutureInterface<T> &), Class *object)
    : fn(fn), object(object) { }

    QFuture<T> start()
    {
        futureInterface.reportStarted();
        QFuture<T> future = futureInterface.future();
        QThreadPool::globalInstance()->start(this);
        return future;
    }

    void run()
    {
        (object->*fn)(futureInterface);
        futureInterface.reportFinished();
    }
private:
    QFutureInterface<T> futureInterface;
    FunctionPointer fn;
    Class *object;

};

template <typename T,  typename FunctionPointer, typename Arg1>
class StoredInterfaceFunctionCall1 : public QRunnable
{
public:
Marco Bubke's avatar
Marco Bubke committed
107
    StoredInterfaceFunctionCall1(void (fn)(QFutureInterface<T> &, Arg1), const Arg1 &arg1)
con's avatar
con committed
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
    : fn(fn), arg1(arg1) { }

    QFuture<T> start()
    {
        futureInterface.reportStarted();
        QFuture<T> future = futureInterface.future();
        QThreadPool::globalInstance()->start(this);
        return future;
    }

    void run()
    {
        fn(futureInterface, arg1);
        futureInterface.reportFinished();
    }
private:
    QFutureInterface<T> futureInterface;
    FunctionPointer fn;
    Arg1 arg1;
};
template <typename T,  typename FunctionPointer, typename Class, typename Arg1>
class StoredInterfaceMemberFunctionCall1 : public QRunnable
{
public:
Marco Bubke's avatar
Marco Bubke committed
132
    StoredInterfaceMemberFunctionCall1(void (Class::*fn)(QFutureInterface<T> &, Arg1), Class *object, const Arg1 &arg1)
con's avatar
con committed
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
    : fn(fn), object(object), arg1(arg1) { }

    QFuture<T> start()
    {
        futureInterface.reportStarted();
        QFuture<T> future = futureInterface.future();
        QThreadPool::globalInstance()->start(this);
        return future;
    }

    void run()
    {
        (object->*fn)(futureInterface, arg1);
        futureInterface.reportFinished();
    }
private:
    QFutureInterface<T> futureInterface;
    FunctionPointer fn;
    Class *object;
    Arg1 arg1;
};

template <typename T,  typename FunctionPointer, typename Arg1, typename Arg2>
class StoredInterfaceFunctionCall2 : public QRunnable
{
public:
Marco Bubke's avatar
Marco Bubke committed
159
    StoredInterfaceFunctionCall2(void (fn)(QFutureInterface<T> &, Arg1, Arg2), const Arg1 &arg1, const Arg2 &arg2)
con's avatar
con committed
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
    : fn(fn), arg1(arg1), arg2(arg2) { }

    QFuture<T> start()
    {
        futureInterface.reportStarted();
        QFuture<T> future = futureInterface.future();
        QThreadPool::globalInstance()->start(this);
        return future;
    }

    void run()
    {
        fn(futureInterface, arg1, arg2);
        futureInterface.reportFinished();
    }
private:
    QFutureInterface<T> futureInterface;
    FunctionPointer fn;
    Arg1 arg1; Arg2 arg2;
};
template <typename T,  typename FunctionPointer, typename Class, typename Arg1, typename Arg2>
class StoredInterfaceMemberFunctionCall2 : public QRunnable
{
public:
Marco Bubke's avatar
Marco Bubke committed
184
    StoredInterfaceMemberFunctionCall2(void (Class::*fn)(QFutureInterface<T> &, Arg1, Arg2), Class *object, const Arg1 &arg1, const Arg2 &arg2)
con's avatar
con committed
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
    : fn(fn), object(object), arg1(arg1), arg2(arg2) { }

    QFuture<T> start()
    {
        futureInterface.reportStarted();
        QFuture<T> future = futureInterface.future();
        QThreadPool::globalInstance()->start(this);
        return future;
    }

    void run()
    {
        (object->*fn)(futureInterface, arg1, arg2);
        futureInterface.reportFinished();
    }
private:
    QFutureInterface<T> futureInterface;
    FunctionPointer fn;
    Class *object;
    Arg1 arg1; Arg2 arg2;
};

template <typename T,  typename FunctionPointer, typename Arg1, typename Arg2, typename Arg3>
class StoredInterfaceFunctionCall3 : public QRunnable
{
public:
Marco Bubke's avatar
Marco Bubke committed
211
    StoredInterfaceFunctionCall3(void (fn)(QFutureInterface<T> &, Arg1, Arg2, Arg3), const Arg1 &arg1, const Arg2 &arg2, const Arg3 &arg3)
con's avatar
con committed
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
    : fn(fn), arg1(arg1), arg2(arg2), arg3(arg3) { }

    QFuture<T> start()
    {
        futureInterface.reportStarted();
        QFuture<T> future = futureInterface.future();
        QThreadPool::globalInstance()->start(this);
        return future;
    }

    void run()
    {
        fn(futureInterface, arg1, arg2, arg3);
        futureInterface.reportFinished();
    }
private:
    QFutureInterface<T> futureInterface;
    FunctionPointer fn;
    Arg1 arg1; Arg2 arg2; Arg3 arg3;
};
template <typename T,  typename FunctionPointer, typename Class, typename Arg1, typename Arg2, typename Arg3>
class StoredInterfaceMemberFunctionCall3 : public QRunnable
{
public:
Marco Bubke's avatar
Marco Bubke committed
236
    StoredInterfaceMemberFunctionCall3(void (Class::*fn)(QFutureInterface<T> &, Arg1, Arg2, Arg3), Class *object, const Arg1 &arg1, const Arg2 &arg2, const Arg3 &arg3)
con's avatar
con committed
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
    : fn(fn), object(object), arg1(arg1), arg2(arg2), arg3(arg3) { }

    QFuture<T> start()
    {
        futureInterface.reportStarted();
        QFuture<T> future = futureInterface.future();
        QThreadPool::globalInstance()->start(this);
        return future;
    }

    void run()
    {
        (object->*fn)(futureInterface, arg1, arg2, arg3);
        futureInterface.reportFinished();
    }
private:
    QFutureInterface<T> futureInterface;
    FunctionPointer fn;
    Class *object;
    Arg1 arg1; Arg2 arg2; Arg3 arg3;
};

template <typename T,  typename FunctionPointer, typename Arg1, typename Arg2, typename Arg3, typename Arg4>
class StoredInterfaceFunctionCall4 : public QRunnable
{
public:
Marco Bubke's avatar
Marco Bubke committed
263
    StoredInterfaceFunctionCall4(void (fn)(QFutureInterface<T> &, Arg1, Arg2, Arg3, Arg4), const Arg1 &arg1, const Arg2 &arg2, const Arg3 &arg3, const Arg4 &arg4)
con's avatar
con committed
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
    : fn(fn), arg1(arg1), arg2(arg2), arg3(arg3), arg4(arg4) { }

    QFuture<T> start()
    {
        futureInterface.reportStarted();
        QFuture<T> future = futureInterface.future();
        QThreadPool::globalInstance()->start(this);
        return future;
    }

    void run()
    {
        fn(futureInterface, arg1, arg2, arg3, arg4);
        futureInterface.reportFinished();
    }
private:
    QFutureInterface<T> futureInterface;
    FunctionPointer fn;
    Arg1 arg1; Arg2 arg2; Arg3 arg3; Arg4 arg4;
};
template <typename T,  typename FunctionPointer, typename Class, typename Arg1, typename Arg2, typename Arg3, typename Arg4>
class StoredInterfaceMemberFunctionCall4 : public QRunnable
{
public:
Marco Bubke's avatar
Marco Bubke committed
288
    StoredInterfaceMemberFunctionCall4(void (Class::*fn)(QFutureInterface<T> &, Arg1, Arg2, Arg3, Arg4), Class *object, const Arg1 &arg1, const Arg2 &arg2, const Arg3 &arg3, const Arg4 &arg4)
con's avatar
con committed
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
    : fn(fn), object(object), arg1(arg1), arg2(arg2), arg3(arg3), arg4(arg4) { }

    QFuture<T> start()
    {
        futureInterface.reportStarted();
        QFuture<T> future = futureInterface.future();
        QThreadPool::globalInstance()->start(this);
        return future;
    }

    void run()
    {
        (object->*fn)(futureInterface, arg1, arg2, arg3, arg4);
        futureInterface.reportFinished();
    }
private:
    QFutureInterface<T> futureInterface;
    FunctionPointer fn;
    Class *object;
    Arg1 arg1; Arg2 arg2; Arg3 arg3; Arg4 arg4;
};

template <typename T,  typename FunctionPointer, typename Arg1, typename Arg2, typename Arg3, typename Arg4, typename Arg5>
class StoredInterfaceFunctionCall5 : public QRunnable
{
public:
Marco Bubke's avatar
Marco Bubke committed
315
    StoredInterfaceFunctionCall5(void (fn)(QFutureInterface<T> &, Arg1, Arg2, Arg3, Arg4, Arg5), const Arg1 &arg1, const Arg2 &arg2, const Arg3 &arg3, const Arg4 &arg4, const Arg5 &arg5)
con's avatar
con committed
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
    : fn(fn), arg1(arg1), arg2(arg2), arg3(arg3), arg4(arg4), arg5(arg5) { }

    QFuture<T> start()
    {
        futureInterface.reportStarted();
        QFuture<T> future = futureInterface.future();
        QThreadPool::globalInstance()->start(this);
        return future;
    }

    void run()
    {
        fn(futureInterface, arg1, arg2, arg3, arg4, arg5);
        futureInterface.reportFinished();
    }
private:
    QFutureInterface<T> futureInterface;
    FunctionPointer fn;
    Arg1 arg1; Arg2 arg2; Arg3 arg3; Arg4 arg4; Arg5 arg5;
};
template <typename T,  typename FunctionPointer, typename Class, typename Arg1, typename Arg2, typename Arg3, typename Arg4, typename Arg5>
class StoredInterfaceMemberFunctionCall5 : public QRunnable
{
public:
Marco Bubke's avatar
Marco Bubke committed
340
    StoredInterfaceMemberFunctionCall5(void (Class::*fn)(QFutureInterface<T> &, Arg1, Arg2, Arg3, Arg4, Arg5), Class *object, const Arg1 &arg1, const Arg2 &arg2, const Arg3 &arg3, const Arg4 &arg4, const Arg5 &arg5)
con's avatar
con committed
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
    : fn(fn), object(object), arg1(arg1), arg2(arg2), arg3(arg3), arg4(arg4), arg5(arg5) { }

    QFuture<T> start()
    {
        futureInterface.reportStarted();
        QFuture<T> future = futureInterface.future();
        QThreadPool::globalInstance()->start(this);
        return future;
    }

    void run()
    {
        (object->*fn)(futureInterface, arg1, arg2, arg3, arg4, arg5);
        futureInterface.reportFinished();
    }
private:
    QFutureInterface<T> futureInterface;
    FunctionPointer fn;
    Class *object;
    Arg1 arg1; Arg2 arg2; Arg3 arg3; Arg4 arg4; Arg5 arg5;
};

template <typename T>
QFuture<T> run(void (*functionPointer)(QFutureInterface<T> &))
{
    return (new StoredInterfaceFunctionCall0<T, void (*)(QFutureInterface<T> &)>(functionPointer))->start();
}
template <typename T, typename Arg1>
Marco Bubke's avatar
Marco Bubke committed
369
QFuture<T> run(void (*functionPointer)(QFutureInterface<T> &, Arg1), const Arg1 &arg1)
con's avatar
con committed
370
371
372
373
{
    return (new StoredInterfaceFunctionCall1<T, void (*)(QFutureInterface<T> &, Arg1), Arg1>(functionPointer, arg1))->start();
}
template <typename T, typename Arg1, typename Arg2>
Marco Bubke's avatar
Marco Bubke committed
374
QFuture<T> run(void (*functionPointer)(QFutureInterface<T> &, Arg1, Arg2), const Arg1 &arg1, const Arg2 &arg2)
con's avatar
con committed
375
376
377
378
{
    return (new StoredInterfaceFunctionCall2<T, void (*)(QFutureInterface<T> &, Arg1, Arg2), Arg1, Arg2>(functionPointer, arg1, arg2))->start();
}
template <typename T, typename Arg1, typename Arg2, typename Arg3>
Marco Bubke's avatar
Marco Bubke committed
379
QFuture<T> run(void (*functionPointer)(QFutureInterface<T> &, Arg1, Arg2, Arg3), const Arg1 &arg1, const Arg2 &arg2, const Arg3 &arg3)
con's avatar
con committed
380
381
382
383
{
    return (new StoredInterfaceFunctionCall3<T, void (*)(QFutureInterface<T> &, Arg1, Arg2, Arg3), Arg1, Arg2, Arg3>(functionPointer, arg1, arg2, arg3))->start();
}
template <typename T, typename Arg1, typename Arg2, typename Arg3, typename Arg4>
Marco Bubke's avatar
Marco Bubke committed
384
QFuture<T> run(void (*functionPointer)(QFutureInterface<T> &, Arg1, Arg2, Arg3, Arg4), const Arg1 &arg1, const Arg2 &arg2, const Arg3 &arg3, const Arg4 &arg4)
con's avatar
con committed
385
386
387
388
{
    return (new StoredInterfaceFunctionCall4<T, void (*)(QFutureInterface<T> &, Arg1, Arg2, Arg3, Arg4), Arg1, Arg2, Arg3, Arg4>(functionPointer, arg1, arg2, arg3, arg4))->start();
}
template <typename T, typename Arg1, typename Arg2, typename Arg3, typename Arg4, typename Arg5>
Marco Bubke's avatar
Marco Bubke committed
389
QFuture<T> run(void (*functionPointer)(QFutureInterface<T> &, Arg1, Arg2, Arg3, Arg4, Arg5), const Arg1 &arg1, const Arg2 &arg2, const Arg3 &arg3, const Arg4 &arg4, const Arg5 &arg5)
con's avatar
con committed
390
391
392
393
394
395
396
397
398
399
{
    return (new StoredInterfaceFunctionCall5<T, void (*)(QFutureInterface<T> &, Arg1, Arg2, Arg3, Arg4, Arg5), Arg1, Arg2, Arg3, Arg4, Arg5>(functionPointer, arg1, arg2, arg3, arg4, arg5))->start();
}

template <typename Class, typename T>
QFuture<T> run(void (Class::*fn)(QFutureInterface<T> &), Class *object)
{
    return (new StoredInterfaceMemberFunctionCall0<T, void (Class::*)(QFutureInterface<T> &), Class>(fn, object))->start();
}

Marco Bubke's avatar
Marco Bubke committed
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
template <typename Class, typename T, typename Arg1>
QFuture<T> run(void (Class::*fn)(QFutureInterface<T> &, Arg1), Class *object, Arg1 arg1)
{
    return (new StoredInterfaceMemberFunctionCall1<T, void (Class::*)(QFutureInterface<T> &, Arg1), Class, Arg1>(fn, object, arg1))->start();
}

template <typename Class, typename T, typename Arg1, typename Arg2>
QFuture<T> run(void (Class::*fn)(QFutureInterface<T> &, Arg1, Arg2), Class *object, const Arg1 &arg1, const Arg2 &arg2)
{
    return (new StoredInterfaceMemberFunctionCall2<T, void (Class::*)(QFutureInterface<T> &, Arg1, Arg2), Class, Arg1, Arg2>(fn, object, arg1, arg2))->start();
}

template <typename Class, typename T, typename Arg1, typename Arg2, typename Arg3>
QFuture<T> run(void (Class::*fn)(QFutureInterface<T> &, Arg1, Arg2, Arg3), Class *object, const Arg1 &arg1, const Arg2 &arg2, const Arg3 &arg3)
{
    return (new StoredInterfaceMemberFunctionCall3<T, void (Class::*)(QFutureInterface<T> &, Arg1, Arg2, Arg3), Class, Arg1, Arg2, Arg3>(fn, object, arg1, arg2, arg3))->start();
}

template <typename Class, typename T, typename Arg1, typename Arg2, typename Arg3, typename Arg4>
QFuture<T> run(void (Class::*fn)(QFutureInterface<T> &, Arg1, Arg2, Arg3, Arg4), Class *object, const Arg1 &arg1, const Arg2 &arg2, const Arg3 &arg3, const Arg4 &arg4)
{
    return (new StoredInterfaceMemberFunctionCall4<T, void (Class::*)(QFutureInterface<T> &, Arg1, Arg2, Arg3, Arg4), Class, Arg1, Arg2, Arg3, Arg4>(fn, object, arg1, arg2, arg3, arg4))->start();
}

template <typename Class, typename T, typename Arg1, typename Arg2, typename Arg3, typename Arg4, typename Arg5>
QFuture<T> run(void (Class::*fn)(QFutureInterface<T> &, Arg1, Arg2, Arg3, Arg4, Arg5), Class *object, const Arg1 &arg1, const Arg2 &arg2, const Arg3 &arg3, const Arg4 &arg4, const Arg5 &arg5)
{
    return (new StoredInterfaceMemberFunctionCall5<T, void (Class::*)(QFutureInterface<T> &, Arg1, Arg2, Arg3, Arg4, Arg5), Class, Arg1, Arg2, Arg3, Arg4, Arg5>(fn, object, arg1, arg2, arg3, arg4, arg5))->start();
}
429
430
431
432

template <typename T>
QFuture<T> run(const std::function<void (QFutureInterface<T> &)> &fn)
{
433
    return (new StoredInterfaceFunctionCall0<T, std::function<void (QFutureInterface<T> &)>>(fn))->start();
434
435
}

hjk's avatar
hjk committed
436
} // namespace QtConcurrent
con's avatar
con committed
437
438
439

QT_END_NAMESPACE

440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
namespace Utils {

template<typename T>
typename std::vector<std::future<T>>::iterator
waitForAny(std::vector<std::future<T>> &futures)
{
    // Wait for any future to have a result ready.
    // Unfortunately we have to do that in a busy loop because future doesn't have a feature to
    // wait for any of a set of futures (yet? possibly when_any in C++17).
    auto end = futures.end();
    QTC_ASSERT(!futures.empty(), return end);
    auto futureIterator = futures.begin();
    forever {
        if (futureIterator->wait_for(std::chrono::duration<quint64>::zero()) == std::future_status::ready)
            return futureIterator;
        ++futureIterator;
        if (futureIterator == end)
            futureIterator = futures.begin();
    }
}

namespace Internal {

template<typename T>
void swapErase(std::vector<T> &vec, typename std::vector<T>::iterator it)
{
    // efficient erasing by swapping with back element
    *it = std::move(vec.back());
    vec.pop_back();
}

template <typename MapResult, typename State, typename ReduceResult, typename ReduceFunction>
void reduceOne(QFutureInterface<ReduceResult> &futureInterface,
               std::vector<std::future<MapResult>> &futures,
               State &state, const ReduceFunction &reduce)
{
    auto futureIterator = waitForAny(futures);
    if (futureIterator != futures.end()) {
        reduce(futureInterface, state, futureIterator->get());
        swapErase(futures, futureIterator);
    }
}

// This together with reduceOne can be replaced by std::transformReduce (parallelism TS)
// when that becomes widely available in C++ implementations
template <typename Container, typename MapFunction, typename State, typename ReduceResult, typename ReduceFunction>
void mapReduceLoop(QFutureInterface<ReduceResult> &futureInterface, const Container &container,
               const MapFunction &map, State &state, const ReduceFunction &reduce)
{
    const unsigned MAX_THREADS = std::thread::hardware_concurrency();
    using MapResult = typename std::result_of<MapFunction(QFutureInterface<ReduceResult>,typename Container::value_type)>::type;
    std::vector<std::future<MapResult>> futures;
    futures.reserve(MAX_THREADS);
    auto fileIterator = container.begin();
    auto end = container.end();
    while (!futureInterface.isCanceled() && (fileIterator != end || futures.size() != 0)) {
        if (futures.size() >= MAX_THREADS || fileIterator == end) {
            // We don't want to start a new thread (yet), so try to find a future that is ready and
            // handle its result.
            reduceOne(futureInterface, futures, state, reduce);
        } else { // start a new thread
            futures.push_back(std::async(std::launch::async,
                                         map, futureInterface, *fileIterator));
            ++fileIterator;
        }
    }
}

template <typename Container, typename InitFunction, typename MapFunction, typename ReduceResult,
          typename ReduceFunction, typename CleanUpFunction>
void blockingMapReduce(QFutureInterface<ReduceResult> futureInterface, const Container &container,
                       const InitFunction &init, const MapFunction &map,
                       const ReduceFunction &reduce, const CleanUpFunction &cleanup)
{
    auto state = init(futureInterface);
    mapReduceLoop(futureInterface, container, map, state, reduce);
    cleanup(futureInterface, state);
    if (futureInterface.isPaused())
        futureInterface.waitForResume();
    futureInterface.reportFinished();
}

522
523
524
525
526
527
528
529
530
template <typename ResultType, typename Function, typename... Args>
void runAsyncImpl(QFutureInterface<ResultType> futureInterface, const Function &function, const Args&... args)
{
    function(futureInterface, args...);
    if (futureInterface.isPaused())
        futureInterface.waitForResume();
    futureInterface.reportFinished();
}

531
532
533
534
535
536
537
538
539
540
} // Internal

template <typename ReduceResult, typename Container, typename InitFunction, typename MapFunction,
          typename ReduceFunction, typename CleanUpFunction>
QFuture<ReduceResult> mapReduce(std::reference_wrapper<Container> containerWrapper,
                                const InitFunction &init, const MapFunction &map,
                                const ReduceFunction &reduce, const CleanUpFunction &cleanup)
{
    auto fi = QFutureInterface<ReduceResult>();
    QFuture<ReduceResult> future = fi.future();
541
    fi.reportStarted();
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
    std::thread(Internal::blockingMapReduce<Container, InitFunction, MapFunction, ReduceResult, ReduceFunction, CleanUpFunction>,
                fi, containerWrapper, init, map, reduce, cleanup).detach();
    return future;
}

template <typename ReduceResult, typename Container, typename InitFunction, typename MapFunction,
          typename ReduceFunction, typename CleanUpFunction>
QFuture<ReduceResult> mapReduce(const Container &container, const InitFunction &init, const MapFunction &map,
               const ReduceFunction &reduce, const CleanUpFunction &cleanup)
{
    auto fi = QFutureInterface<ReduceResult>();
    QFuture<ReduceResult> future = fi.future();
    std::thread(Internal::blockingMapReduce<Container, InitFunction, MapFunction, ReduceResult, ReduceFunction, CleanUpFunction>,
                fi, container, init, map, reduce, cleanup).detach();
    return future;
}

559
560
561
562
template <typename ResultType, typename Function, typename... Args>
QFuture<ResultType> runAsync(Function &&function, Args&&... args)
{
    QFutureInterface<ResultType> futureInterface;
563
    futureInterface.reportStarted();
564
565
566
567
568
    std::thread(Internal::runAsyncImpl<ResultType,Function,Args...>, futureInterface,
                std::forward<Function>(function), std::forward<Args>(args)...).detach();
    return futureInterface.future();
}

569
570
} // Utils

571
#endif // RUNEXTENSIONS_H