1 | #ifndef BOOST_SMART_PTR_ENABLE_SHARED_FROM_THIS_HPP_INCLUDED |
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2 | #define BOOST_SMART_PTR_ENABLE_SHARED_FROM_THIS_HPP_INCLUDED |
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3 | |
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4 | // |
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5 | // enable_shared_from_this.hpp |
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6 | // |
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7 | // Copyright 2002, 2009 Peter Dimov |
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8 | // |
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9 | // Distributed under the Boost Software License, Version 1.0. |
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10 | // See accompanying file LICENSE_1_0.txt or copy at |
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11 | // http://www.boost.org/LICENSE_1_0.txt |
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12 | // |
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13 | // http://www.boost.org/libs/smart_ptr/enable_shared_from_this.html |
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14 | // |
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15 | |
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16 | #include <boost/smart_ptr/weak_ptr.hpp> |
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17 | #include <boost/smart_ptr/shared_ptr.hpp> |
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18 | #include <boost/assert.hpp> |
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19 | #include <boost/config.hpp> |
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20 | |
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21 | namespace boost |
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22 | { |
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23 | |
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24 | template<class T> class enable_shared_from_this |
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25 | { |
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26 | protected: |
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27 | |
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28 | enable_shared_from_this() |
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29 | { |
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30 | } |
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31 | |
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32 | enable_shared_from_this(enable_shared_from_this const &) |
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33 | { |
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34 | } |
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35 | |
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36 | enable_shared_from_this & operator=(enable_shared_from_this const &) |
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37 | { |
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38 | return *this; |
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39 | } |
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40 | |
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41 | ~enable_shared_from_this() |
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42 | { |
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43 | } |
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44 | |
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45 | public: |
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46 | |
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47 | shared_ptr<T> shared_from_this() |
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48 | { |
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49 | shared_ptr<T> p( weak_this_ ); |
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50 | BOOST_ASSERT( p.get() == this ); |
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51 | return p; |
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52 | } |
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53 | |
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54 | shared_ptr<T const> shared_from_this() const |
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55 | { |
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56 | shared_ptr<T const> p( weak_this_ ); |
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57 | BOOST_ASSERT( p.get() == this ); |
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58 | return p; |
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59 | } |
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60 | |
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61 | public: // actually private, but avoids compiler template friendship issues |
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62 | |
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63 | // Note: invoked automatically by shared_ptr; do not call |
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64 | template<class X, class Y> void _internal_accept_owner( shared_ptr<X> const * ppx, Y * py ) const |
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65 | { |
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66 | if( weak_this_.expired() ) |
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67 | { |
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68 | weak_this_ = shared_ptr<T>( *ppx, py ); |
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69 | } |
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70 | } |
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71 | |
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72 | private: |
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73 | |
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74 | mutable weak_ptr<T> weak_this_; |
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75 | }; |
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76 | |
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77 | } // namespace boost |
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78 | |
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79 | #endif // #ifndef BOOST_SMART_PTR_ENABLE_SHARED_FROM_THIS_HPP_INCLUDED |
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