1 // Copyright (C) 2006 Douglas Gregor <doug.gregor -at- gmail.com>.
2 
3 // Use, modification and distribution is subject to the Boost Software
4 // License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
5 // http://www.boost.org/LICENSE_1_0.txt)
6 
7 /** @file request.hpp
8  *
9  *  This header defines the class @c request, which contains a request
10  *  for non-blocking communication.
11  */
12 #ifndef BOOST_MPI_REQUEST_HPP
13 #define BOOST_MPI_REQUEST_HPP
14 
15 #include <boost/mpi/config.hpp>
16 #include <boost/mpi/status.hpp>
17 #include <boost/optional.hpp>
18 #include <boost/shared_ptr.hpp>
19 #include <boost/mpi/packed_iarchive.hpp>
20 
21 namespace boost { namespace mpi {
22 
23 class status;
24 class communicator;
25 
26 /**
27  *  @brief A request for a non-blocking send or receive.
28  *
29  *  This structure contains information about a non-blocking send or
30  *  receive and will be returned from @c isend or @c irecv,
31  *  respectively.
32  */
33 class BOOST_MPI_DECL request
34 {
35  public:
36   /**
37    *  Constructs a NULL request.
38    */
39   request();
40 
41   /**
42    * Send a known number of primitive objects in one MPI request.
43    */
44   template<typename T>
45   static request make_trivial_send(communicator const& comm, int dest, int tag, T const& value);
46   template<typename T>
47   static request make_trivial_send(communicator const& comm, int dest, int tag, T const* values, int n);
48   static request make_packed_send(communicator const& comm, int dest, int tag, void const* values, std::size_t n);
49 
50   static request make_bottom_send(communicator const& comm, int dest, int tag, MPI_Datatype tp);
51   static request make_empty_send(communicator const& comm, int dest, int tag);
52   /**
53    * Receive a known number of primitive objects in one MPI request.
54    */
55   template<typename T>
56   static request make_trivial_recv(communicator const& comm, int dest, int tag, T& value);
57   template<typename T>
58   static request make_trivial_recv(communicator const& comm, int dest, int tag, T* values, int n);
59 
60   static request make_bottom_recv(communicator const& comm, int dest, int tag, MPI_Datatype tp);
61   static request make_empty_recv(communicator const& comm, int dest, int tag);
62   /**
63    * Construct request for simple data of unknown size.
64    */
65   static request make_dynamic();
66   /**
67    *  Constructs request for serialized data.
68    */
69   template<typename T>
70   static request make_serialized(communicator const& comm, int source, int tag, T& value);
71   /**
72    *  Constructs request for array of complex data.
73    */
74   template<typename T>
75   static request make_serialized_array(communicator const& comm, int source, int tag, T* values, int n);
76   /**
77    *  Request to recv array of primitive data.
78    */
79   template<typename T, class A>
80   static request
81   make_dynamic_primitive_array_recv(communicator const& comm, int source, int tag,
82                                     std::vector<T,A>& values);
83   /**
84    *  Request to send array of primitive data.
85    */
86   template<typename T, class A>
87   static request
88   make_dynamic_primitive_array_send(communicator const& comm, int source, int tag,
89                                     std::vector<T,A> const& values);
90   /**
91    *  Wait until the communication associated with this request has
92    *  completed, then return a @c status object describing the
93    *  communication.
94    */
wait()95   status wait() { return m_handler ? m_handler->wait() : status(); }
96 
97   /**
98    *  Determine whether the communication associated with this request
99    *  has completed successfully. If so, returns the @c status object
100    *  describing the communication. Otherwise, returns an empty @c
101    *  optional<> to indicate that the communication has not completed
102    *  yet. Note that once @c test() returns a @c status object, the
103    *  request has completed and @c wait() should not be called.
104    */
test()105   optional<status> test() { return active() ? m_handler->test() : optional<status>(); }
106 
107   /**
108    *  Cancel a pending communication, assuming it has not already been
109    *  completed.
110    */
cancel()111   void cancel() { if (m_handler) { m_handler->cancel(); } m_preserved.reset(); }
112 
113   /**
114    * The trivial MPI requet implenting this request, provided it's trivial.
115    * Probably irrelevant to most users.
116    */
trivial()117   optional<MPI_Request&> trivial() { return (m_handler
118 					     ? m_handler->trivial()
119 					     : optional<MPI_Request&>()); }
120 
121   /**
122    * Is this request potentialy pending ?
123    */
active() const124   bool active() const { return bool(m_handler) && m_handler->active(); }
125 
126   // Some data might need protection while the reqest is processed.
127   void preserve(boost::shared_ptr<void> d);
128 
129   class handler {
130   public:
131     virtual BOOST_MPI_DECL ~handler() = 0;
132     virtual status wait() = 0;
133     virtual optional<status> test() = 0;
134     virtual void cancel() = 0;
135 
136     virtual bool active() const = 0;
137     virtual optional<MPI_Request&> trivial() = 0;
138   };
139 
140  private:
141 
request(handler * h)142   request(handler *h) : m_handler(h) {};
143 
144   // specific implementations
145   class legacy_handler;
146   class trivial_handler;
147   class dynamic_handler;
148   template<typename T> class legacy_serialized_handler;
149   template<typename T> class legacy_serialized_array_handler;
150   template<typename T, class A> class legacy_dynamic_primitive_array_handler;
151 #if BOOST_MPI_VERSION >= 3
152   template<class Data> class probe_handler;
153 #endif
154  private:
155   shared_ptr<handler> m_handler;
156   shared_ptr<void>    m_preserved;
157 };
158 
159 } } // end namespace boost::mpi
160 
161 #endif // BOOST_MPI_REQUEST_HPP
162