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1 | /*************************************************************************** |
2 | * Copyright (C) 2008 by Gerd v. Egidy and Reinhard Pfau * | |
3 | * gve@intra2net.com * | |
4 | * * | |
5 | * This library is free software; you can redistribute it and/or modify * | |
6 | * it under the terms of the GNU Lesser General Public License version * | |
7 | * 2.1 as published by the Free Software Foundation. * | |
8 | * * | |
9 | * This library is distributed in the hope that it will be useful, * | |
10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of * | |
11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * | |
12 | * GNU Lesser General Public License for more details. * | |
13 | * * | |
14 | * You should have received a copy of the GNU Lesser General Public * | |
15 | * License along with this program; if not, write to the * | |
16 | * Free Software Foundation, Inc., * | |
17 | * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. * | |
18 | ***************************************************************************/ | |
19 | #ifndef __LIBT2N_CLIENT_WRAPPER | |
20 | #define __LIBT2N_CLIENT_WRAPPER | |
21 | ||
22 | #include <functional> | |
23 | ||
24 | #include <boost/config.hpp> | |
45508d07 GE |
25 | #include <boost/bind.hpp> |
26 | #include <boost/function.hpp> | |
27 | #include <boost/preprocessor.hpp> | |
28 | ||
29 | #include <client.hxx> | |
30 | #include <command_client.hxx> | |
31 | ||
0ea6d528 GE |
32 | #ifndef T2N_SINGLETON_WRAPPER_MAX_ARGS |
33 | #define T2N_SINGLETON_WRAPPER_MAX_ARGS 9 | |
45508d07 GE |
34 | #endif |
35 | ||
36 | namespace libt2n | |
37 | { | |
38 | ||
e162ddf2 GE |
39 | /** @brief provide access to client_connection singletons and call-handling function |
40 | ||
41 | This is an abstact base class for use with T2nSingletonWrapper. It provides access | |
42 | to the singleton-client_connection and offers a handle-method which is used for | |
43 | every call to a method on a t2n-server. | |
44 | */ | |
0ea6d528 | 45 | class ConnectionWrapper |
45508d07 | 46 | { |
e1614a6d GE |
47 | private: |
48 | long long command_timeout_usec; | |
49 | long long hello_timeout_usec; | |
45508d07 | 50 | |
e1614a6d GE |
51 | protected: |
52 | log_level_values log_level; | |
53 | std::ostream *logstream; | |
54 | void set_logging_on_connection(client_connection& c); | |
45508d07 | 55 | |
e1614a6d GE |
56 | public: |
57 | ConnectionWrapper() | |
58 | : log_level(none), logstream(NULL), | |
59 | command_timeout_usec(command_client::command_timeout_usec_default), | |
60 | hello_timeout_usec(command_client::hello_timeout_usec_default) | |
61 | { } | |
45508d07 | 62 | |
e1614a6d GE |
63 | virtual ~ConnectionWrapper() |
64 | { } | |
65 | ||
e162ddf2 GE |
66 | /** @brief return active connection, create new one if not existing |
67 | ||
68 | Return a pointer to an active client_connection. Use detail-data | |
69 | stored within the derived class to create a new connection if needed, | |
70 | otherwise return an alredy active connection. The derived class has | |
71 | to take care of destroying the connection when not needed anymore. | |
72 | */ | |
e1614a6d | 73 | virtual client_connection* get_connection()=0; |
0ea6d528 | 74 | |
e162ddf2 GE |
75 | /** @brief this function is called on every execution of a method on a server |
76 | ||
77 | @param stubBase pointer to the command_client executing the call | |
78 | @param f boost::function object containing the method to call and all parameters | |
79 | @retval true if the call was successful and the original return-value of the called function can be used | |
80 | false if T2nSingletonWrapper has to create a return-value with the default-constructor | |
81 | ||
82 | T2nSingletonWrapper will call this function on every execution of a server-side | |
83 | method. This version will just call the function without any special treatment. | |
84 | You can overload this function to implement different error handling strategies. | |
85 | */ | |
fb3345ad | 86 | virtual bool handle(command_client* stubBase, boost::function< void() > f) |
45508d07 GE |
87 | { |
88 | f(); | |
fb3345ad | 89 | return true; |
45508d07 | 90 | } |
0ea6d528 | 91 | |
e1614a6d GE |
92 | long long get_command_timeout_usec(void) |
93 | { return command_timeout_usec; } | |
94 | ||
95 | void set_command_timeout_usec(long long _command_timeout_usec) | |
96 | { command_timeout_usec=_command_timeout_usec; } | |
97 | ||
98 | long long get_hello_timeout_usec(void) | |
99 | { return hello_timeout_usec; } | |
100 | ||
101 | void set_hello_timeout_usec(long long _hello_timeout_usec) | |
102 | { hello_timeout_usec=_hello_timeout_usec; } | |
103 | ||
2a956e65 | 104 | virtual void set_logging(std::ostream *_logstream, log_level_values _log_level); |
e1614a6d GE |
105 | |
106 | std::ostream* get_logstream(log_level_values level); | |
45508d07 GE |
107 | }; |
108 | ||
109 | // contains the internal stuff needed for T2nWrapper | |
110 | namespace detail | |
111 | { | |
112 | ||
113 | template< typename T > | |
114 | struct TypeWrap | |
115 | { | |
116 | typedef T type; | |
117 | }; | |
118 | ||
119 | template< > | |
120 | struct TypeWrap< void > | |
121 | { | |
122 | typedef int type; | |
123 | }; | |
124 | ||
125 | template< typename R > | |
126 | struct Call | |
127 | { | |
128 | typedef boost::function< R() > FuncType; | |
129 | ||
130 | FuncType function; | |
131 | R& result; | |
132 | ||
133 | Call( FuncType f, R& res ) : function(f), result( res ) {} | |
134 | ||
135 | void operator()() | |
136 | { | |
137 | result= function(); | |
138 | } | |
139 | }; | |
140 | ||
141 | template< > | |
142 | struct Call<void> | |
143 | { | |
144 | typedef boost::function< void() > FuncType; | |
145 | typedef TypeWrap< void >::type ResultType; | |
146 | ||
147 | FuncType function; | |
148 | ResultType& result; | |
149 | ||
150 | Call( FuncType f, ResultType& res ) : function(f), result( res ) {} | |
151 | ||
152 | void operator()() | |
153 | { | |
154 | function(); | |
155 | result= ResultType(); | |
156 | } | |
157 | }; | |
158 | } // eo namespace detail | |
159 | ||
0ea6d528 | 160 | class T2nSingletonWrapperMessages |
45508d07 | 161 | { |
0ea6d528 GE |
162 | protected: |
163 | static const char* NotInitializedMessage; | |
164 | }; | |
45508d07 | 165 | |
e162ddf2 GE |
166 | /** @brief wrap calls to server-side-functions with different error-handling strategies |
167 | ||
168 | Template class to access a process-wide singleton server-connection and to wrap all | |
169 | calls using this connection with an error-handling strategy (e.g. to reconnect when | |
170 | the connection broke). The source looks very complicated due to heavy use of templates, | |
171 | look at the 3rd codegen example to see how to use it. | |
9a5d7790 GE |
172 | |
173 | @par Example | |
174 | Calling remote methods is usually done via t2n_exec, this saves you from always | |
175 | specifying which T2nSingletonWrapper-template to use when calling T2nSingletonWrapper::exec | |
176 | @code | |
177 | t2n_exec(&cmd_group_t2nexample_client::testfunc)("the answer is %d",42) | |
178 | @endcode | |
e162ddf2 | 179 | */ |
0ea6d528 GE |
180 | template< class Client > |
181 | class T2nSingletonWrapper : public T2nSingletonWrapperMessages | |
182 | { | |
183 | private: | |
184 | std::auto_ptr<Client> Stub; | |
45508d07 | 185 | |
0ea6d528 GE |
186 | static std::auto_ptr<T2nSingletonWrapper> SingletonObject; |
187 | static std::auto_ptr<ConnectionWrapper> WrappedConnection; | |
45508d07 | 188 | |
9a5d7790 | 189 | /// @cond |
45508d07 GE |
190 | // create a prep-method for each possible number of parameters |
191 | #define _GEN_ARG(z,n,d) Arg ## n arg ##n | |
192 | #define _GEN_PREP(z,n,d) \ | |
193 | template< typename R BOOST_PP_COMMA_IF(n) BOOST_PP_ENUM_PARAMS(n,typename Arg) > \ | |
194 | static boost::function< R(Client*) > prep \ | |
195 | ( \ | |
196 | R(Client::*f)( BOOST_PP_ENUM_PARAMS(n,Arg) ) \ | |
197 | BOOST_PP_COMMA_IF(n) \ | |
198 | BOOST_PP_ENUM( n, _GEN_ARG, ~ ) \ | |
199 | ) \ | |
200 | { \ | |
201 | return boost::bind< R > \ | |
202 | ( \ | |
203 | f, _1 BOOST_PP_COMMA_IF(n) BOOST_PP_ENUM_PARAMS(n,arg) \ | |
204 | ); \ | |
205 | } // eo prep | |
206 | ||
0ea6d528 | 207 | BOOST_PP_REPEAT( BOOST_PP_ADD(T2N_SINGLETON_WRAPPER_MAX_ARGS,1) , _GEN_PREP, ~ ) |
45508d07 GE |
208 | |
209 | #undef _GEN_PREP | |
210 | #undef _GEN_ARG | |
9a5d7790 | 211 | /// @endcond |
45508d07 | 212 | |
a64066eb GE |
213 | T2nSingletonWrapper(std::auto_ptr<Client> stub) |
214 | { | |
215 | Stub=stub; | |
216 | } | |
217 | ||
218 | static void init() | |
45508d07 | 219 | { |
0ea6d528 GE |
220 | if (WrappedConnection.get() == NULL) |
221 | throw std::logic_error(NotInitializedMessage); | |
45508d07 | 222 | |
fb3345ad | 223 | std::auto_ptr<Client> stub(new Client(WrappedConnection->get_connection(), |
0ea6d528 GE |
224 | WrappedConnection->get_command_timeout_usec(), |
225 | WrappedConnection->get_hello_timeout_usec())); | |
a64066eb GE |
226 | |
227 | SingletonObject=std::auto_ptr<T2nSingletonWrapper>(new T2nSingletonWrapper(stub)); | |
45508d07 GE |
228 | } |
229 | ||
230 | template< typename R > | |
231 | static | |
232 | typename detail::TypeWrap<R>::type real_exec( boost::function< R(Client*) > f) | |
233 | { | |
0ea6d528 | 234 | ensure_singleton_there(); |
45508d07 GE |
235 | |
236 | typename detail::TypeWrap<R>::type result; | |
fb3345ad GE |
237 | |
238 | // bind our Client-object and the local result | |
0ea6d528 | 239 | detail::Call<R> call( boost::bind( f, SingletonObject->Stub.get()), result ); |
fb3345ad GE |
240 | |
241 | // let the wrapper-handler call the fully-bound function | |
242 | if (!WrappedConnection->handle(SingletonObject->Stub.get(),call)) | |
243 | { | |
244 | // create an result with default-constructor if the handler could not | |
245 | // successfully do a call but no exception occured | |
246 | result=typename detail::TypeWrap<R>::type(); | |
247 | } | |
45508d07 GE |
248 | return result; |
249 | } | |
250 | ||
251 | public: | |
252 | ||
9a5d7790 GE |
253 | /** @brief tell the wrapper which connection to use |
254 | @param wrappedConnection the connection to establish when needed | |
255 | */ | |
0ea6d528 GE |
256 | static void set_connection(std::auto_ptr<ConnectionWrapper> wrappedConnection) |
257 | { | |
258 | WrappedConnection=wrappedConnection; | |
259 | ||
260 | // reset the singleton to NULL because the singleton must be constructed with current WrappedConnection | |
261 | if (SingletonObject.get() != NULL) | |
262 | SingletonObject.reset(); | |
263 | } | |
9a5d7790 GE |
264 | |
265 | /// return a pointer to the ConnectionWrapper currently in use | |
e1614a6d | 266 | static ConnectionWrapper* get_connection_wrapper(void) |
0ea6d528 | 267 | { return WrappedConnection.get(); } |
45508d07 | 268 | |
9a5d7790 | 269 | /// manually establish the connection without actually executing a call |
0ea6d528 | 270 | static void ensure_singleton_there(void) |
45508d07 | 271 | { |
0ea6d528 | 272 | if (SingletonObject.get() == NULL) |
a64066eb | 273 | init(); |
45508d07 GE |
274 | } |
275 | ||
9a5d7790 | 276 | /// @cond |
45508d07 GE |
277 | // create an exec-method for each possible number of parameters |
278 | #define _GEN_PLACEHOLDER(z,n,d) BOOST_PP_CAT(_,BOOST_PP_ADD(n,1)) | |
279 | #define _GEN_EXEC(z,n,d) \ | |
280 | template< typename R BOOST_PP_COMMA_IF(n) BOOST_PP_ENUM_PARAMS(n,typename Arg) > \ | |
281 | static boost::function< R( BOOST_PP_ENUM_PARAMS(n,Arg) ) > exec \ | |
282 | ( \ | |
283 | R(Client::*f)( BOOST_PP_ENUM_PARAMS(n,Arg) ) \ | |
284 | ) \ | |
285 | { \ | |
286 | boost::function<R(Client*)>(*p)(R(Client::*)( BOOST_PP_ENUM_PARAMS(n,Arg) ) \ | |
287 | BOOST_PP_COMMA_IF(n) BOOST_PP_ENUM_PARAMS(n,Arg)) \ | |
0ea6d528 | 288 | = &T2nSingletonWrapper::template prep<R BOOST_PP_COMMA_IF(n) BOOST_PP_ENUM_PARAMS(n,Arg) >; \ |
45508d07 GE |
289 | return boost::bind \ |
290 | ( \ | |
0ea6d528 | 291 | T2nSingletonWrapper::template real_exec<R>, \ |
45508d07 GE |
292 | boost::bind( p, f BOOST_PP_COMMA_IF(n) \ |
293 | BOOST_PP_ENUM(n, _GEN_PLACEHOLDER, ~ ) ) \ | |
294 | ); \ | |
295 | } // eo exec | |
296 | ||
0ea6d528 | 297 | BOOST_PP_REPEAT( BOOST_PP_ADD(T2N_SINGLETON_WRAPPER_MAX_ARGS,1), _GEN_EXEC, ~ ) |
45508d07 GE |
298 | |
299 | #undef _GEN_EXEC | |
300 | #undef _GEN_PLACEHOLDER | |
9a5d7790 | 301 | /// @endcond |
45508d07 GE |
302 | |
303 | }; | |
304 | ||
9a5d7790 | 305 | /// @cond |
0ea6d528 GE |
306 | // create an t2n_exec-method for each possible number of parameters |
307 | #define _GEN_EXEC(z,n,d) \ | |
308 | template< class Client, typename R BOOST_PP_COMMA_IF(n) BOOST_PP_ENUM_PARAMS(n,typename Arg) > \ | |
309 | static boost::function< R( BOOST_PP_ENUM_PARAMS(n,Arg) ) > t2n_exec \ | |
310 | ( \ | |
311 | R(Client::*f)( BOOST_PP_ENUM_PARAMS(n,Arg) ) \ | |
312 | ) \ | |
313 | { \ | |
314 | return T2nSingletonWrapper<Client>::exec(f); \ | |
315 | } // eo exec | |
316 | ||
317 | BOOST_PP_REPEAT( BOOST_PP_ADD(T2N_SINGLETON_WRAPPER_MAX_ARGS,1), _GEN_EXEC, ~ ) | |
318 | ||
319 | #undef _GEN_EXEC | |
320 | #undef _GEN_PLACEHOLDER | |
9a5d7790 | 321 | /// @endcond |
0ea6d528 | 322 | |
45508d07 GE |
323 | } |
324 | #endif |