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futureFunction.h
1 
2 /* Copyright (c) 2013-2014, Stefan.Eilemann@epfl.ch
3  *
4  * This library is free software; you can redistribute it and/or modify it under
5  * the terms of the GNU Lesser General Public License version 2.1 as published
6  * by the Free Software Foundation.
7  *
8  * This library is distributed in the hope that it will be useful, but WITHOUT
9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
10  * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
11  * details.
12  *
13  * You should have received a copy of the GNU Lesser General Public License
14  * along with this library; if not, write to the Free Software Foundation, Inc.,
15  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
16  */
17 
18 #ifndef LUNCHBOX_FUTUREFUNCTION_H
19 #define LUNCHBOX_FUTUREFUNCTION_H
20 
21 #include <lunchbox/future.h> // base class
22 #include <boost/function/function0.hpp>
23 
24 namespace lunchbox
25 {
27 class FutureTrue : public FutureImpl< bool >
28 {
29 protected:
30  bool wait( const uint32_t ) final { return true; }
31  bool isReady() const final { return true; }
32 };
33 
38 template< class T > class FutureFunction : public FutureImpl< T >
39 {
40 public:
41  typedef boost::function< T() > Func;
42 
43  explicit FutureFunction( const Func& func ) : func_( func ) {}
44 
45 protected:
46  virtual ~FutureFunction() { wait( 0 ); }
47 
48  T wait( const uint32_t ) final
49  {
50  if( !func_.empty( ))
51  {
52  result_ = func_();
53  func_.clear();
54  }
55  return result_;
56  }
57 
58  bool isReady() const final { return func_.empty(); }
59 
60  Func func_;
61  T result_;
62 };
63 
64 }
65 #endif //LUNCHBOX_FUTURE_H
A Future implementation using a boost::function for fulfilment.
boost::function< T() > Func
The fulfilling function.
T wait(const uint32_t) final
Wait for the promise to be fullfilled.
bool isReady() const final
A boolean future always returning true.
bool isReady() const final
Base class to implement the wait method fulfilling the future.
Definition: future.h:37
bool wait(const uint32_t) final
Wait for the promise to be fullfilled.