1 ///////////////////////////////////////////////////////////////////////////// 2 // Name: ipc.h 3 // Purpose: interface of wxConnection 4 // Author: wxWidgets team 5 // Licence: wxWindows licence 6 ///////////////////////////////////////////////////////////////////////////// 7 8 /** 9 @class wxConnection 10 11 A wxConnection object represents the connection between a client and a server. 12 It is created by making a connection using a wxClient object, or by the acceptance 13 of a connection by a wxServer object. 14 15 The bulk of a DDE-like (Dynamic Data Exchange) conversation is controlled by 16 calling members in a @b wxConnection object or by overriding its members. 17 The actual DDE-based implementation using wxDDEConnection is available on 18 Windows only, but a platform-independent, socket-based version of this API is 19 available using wxTCPConnection, which has the same API. 20 21 An application should normally derive a new connection class from wxConnection, 22 in order to override the communication event handlers to do something interesting. 23 24 @library{wxbase} 25 @category{ipc} 26 27 @see wxClient, wxServer, @ref overview_ipc 28 */ 29 class wxConnection : public wxObject 30 { 31 public: 32 //@{ 33 /** 34 Constructs a connection object. 35 36 If no user-defined connection object is to be derived from wxConnection, 37 then the constructor should not be called directly, since the default connection 38 object will be provided on requesting (or accepting) a connection. 39 40 However, if the user defines his or her own derived connection object, 41 the wxServer::OnAcceptConnection and/or wxClient::OnMakeConnection 42 members should be replaced by functions which construct the new 43 connection object. 44 45 If the arguments of the wxConnection constructor are void then 46 the wxConnection object manages its own connection buffer, 47 allocating memory as needed. A programmer-supplied buffer cannot 48 be increased if necessary, and the program will assert if it is 49 not large enough. 50 51 The programmer-supplied buffer is included mainly for backwards compatibility. 52 */ 53 wxConnection(); 54 wxConnection(void* buffer, size_t size); 55 //@} 56 57 //@{ 58 /** 59 Called by the server application to advise the client of a change 60 in the data associated with the given item. Causes the client 61 connection's OnAdvise() member to be called. 62 63 @return @true if successful. 64 */ 65 bool Advise(const wxString& item, const void* data, size_t size, 66 wxIPCFormat format = wxIPC_PRIVATE); 67 bool Advise(const wxString& item, const char* data); 68 bool Advise(const wxString& item, const wchar_t* data); 69 bool Advise(const wxString& item, const wxString data); 70 //@} 71 72 /** 73 Called by the client or server application to disconnect from the 74 other program; it causes the OnDisconnect() message to be sent to the 75 corresponding connection object in the other program. 76 77 Returns @true if successful or already disconnected. 78 The application that calls Disconnect() must explicitly delete 79 its side of the connection. 80 */ 81 bool Disconnect(); 82 83 //@{ 84 /** 85 Called by the client application to execute a command on the server. 86 Can also be used to transfer arbitrary data to the server (similar to 87 Poke() in that respect). Causes the server connection's OnExec() 88 member to be called. Returns @true if successful. 89 */ 90 bool Execute(const void* data, size_t size, 91 wxIPCFormat format = wxIPC_PRIVATE); 92 bool Execute(const char* data); 93 bool Execute(const wchar_t* data); 94 bool Execute(const wxString data); 95 //@} 96 97 /** 98 Message sent to the client application when the server notifies it of a 99 change in the data associated with the given item, using Advise(). 100 */ 101 virtual bool OnAdvise(const wxString& topic, 102 const wxString& item, 103 const void* data, 104 size_t size, 105 wxIPCFormat format); 106 107 /** 108 Message sent to the client or server application when the other 109 application notifies it to end the connection. 110 111 The default behaviour is to delete the connection object and return @true, 112 so applications should generally override OnDisconnect() (finally calling 113 the inherited method as well) so that they know the connection object is 114 no longer available. 115 */ 116 virtual bool OnDisconnect(); 117 118 /** 119 Message sent to the server application when the client notifies 120 it to execute the given data, using Execute(). 121 122 Note that there is no item associated with this message. 123 */ 124 virtual bool OnExec(const wxString& topic, const wxString& data); 125 126 /** 127 Message sent to the server application when the client notifies it to 128 accept the given data. 129 */ 130 virtual bool OnPoke(const wxString& topic, const wxString& item, 131 const void* data, 132 size_t size, 133 wxIPCFormat format); 134 135 /** 136 Message sent to the server application when the client calls Request(). 137 The server's OnRequest() method should respond by returning a character 138 string, or @NULL to indicate no data, and setting *size. 139 140 The character string must of course persist after the call returns. 141 */ 142 virtual const void* OnRequest(const wxString& topic, 143 const wxString& item, 144 size_t* size, 145 wxIPCFormat format); 146 147 /** 148 Message sent to the server application by the client, when the client 149 wishes to start an 'advise loop' for the given topic and item. 150 The server can refuse to participate by returning @false. 151 */ 152 virtual bool OnStartAdvise(const wxString& topic, 153 const wxString& item); 154 155 /** 156 Message sent to the server application by the client, when the client 157 wishes to stop an 'advise loop' for the given topic and item. 158 The server can refuse to stop the advise loop by returning @false, although 159 this doesn't have much meaning in practice. 160 */ 161 virtual bool OnStopAdvise(const wxString& topic, 162 const wxString& item); 163 164 //@{ 165 /** 166 Called by the client application to poke data into the server. 167 Can be used to transfer arbitrary data to the server. 168 Causes the server connection's OnPoke() member to be called. 169 If size is -1 the size is computed from the string length of data. 170 171 Returns @true if successful. 172 */ 173 bool Poke(const wxString& item, const void* data, size_t size, 174 wxIPCFormat format = wxIPC_PRIVATE); 175 bool Poke(const wxString& item, const char* data); 176 bool Poke(const wxString& item, const wchar_t* data); 177 bool Poke(const wxString& item, const wxString data); 178 //@} 179 180 /** 181 Called by the client application to request data from the server. 182 Causes the server connection's OnRequest() member to be called. 183 Size may be @NULL or a pointer to a variable to receive the size of the 184 requested item. 185 186 Returns a character string (actually a pointer to the connection's buffer) 187 if successful, @NULL otherwise. This buffer does not need to be deleted. 188 */ 189 const void* Request(const wxString& item, size_t* size, 190 wxIPCFormat format = wxIPC_TEXT); 191 192 /** 193 Called by the client application to ask if an advise loop can be started 194 with the server. Causes the server connection's OnStartAdvise() 195 member to be called. 196 Returns @true if the server okays it, @false otherwise. 197 */ 198 bool StartAdvise(const wxString& item); 199 200 /** 201 Called by the client application to ask if an advise loop can be stopped. 202 Causes the server connection's OnStopAdvise() member to be called. 203 Returns @true if the server okays it, @false otherwise. 204 */ 205 bool StopAdvise(const wxString& item); 206 207 /** 208 Returns true if the format is one of the text formats. 209 210 The text formats are wxIPC_TEXT, wxIPC_UNICODETEXT and wxIPC_UTF8TEXT. 211 */ 212 static bool IsTextFormat(wxIPCFormat format); 213 214 /** 215 Returns the data in any of the text formats as string. 216 217 @param data 218 The raw data pointer as used with any of the other methods of this 219 class. 220 @param size 221 The size of the data buffer pointed to by @a data. 222 @param format 223 The format of the data. It must be a text one, i.e. such that 224 IsTextFormat() returns @true for it. 225 @return 226 The string representation of the data. If the format is not text, 227 an assertion failure is triggered and empty string is returned. 228 */ 229 static wxString 230 GetTextFromData(const void *data, size_t size, wxIPCFormat format); 231 }; 232 233 234 235 /** 236 @class wxClient 237 238 A wxClient object represents the client part of a client-server 239 DDE-like (Dynamic Data Exchange) conversation. 240 The actual DDE-based implementation using wxDDEClient is available on Windows 241 only, but a platform-independent, socket-based version of this API is available 242 using wxTCPClient, which has the same API. 243 244 To create a client which can communicate with a suitable server, you need to 245 derive a class from wxConnection and another from wxClient. 246 The custom wxConnection class will intercept communications in a 'conversation' 247 with a server, and the custom wxClient is required so that a user-overridden 248 wxClient::OnMakeConnection member can return a wxConnection of the required 249 class, when a connection is made. 250 251 Look at the IPC sample and the @ref overview_ipc for an example of how to do this. 252 253 @library{wxbase} 254 @category{ipc} 255 256 @see wxServer, wxConnection, @ref overview_ipc 257 */ 258 class wxClient : public wxObject 259 { 260 public: 261 /** 262 Constructs a client object. 263 */ 264 wxClient(); 265 266 /** 267 Tries to make a connection with a server by host (machine name 268 under UNIX - use 'localhost' for same machine; ignored when using 269 native DDE in Windows), service name and topic string. 270 271 If the server allows a connection, a wxConnection object will be returned. 272 The type of wxConnection returned can be altered by overriding the 273 OnMakeConnection() member to return your own derived connection object. 274 275 Under Unix, the service name may be either an integer port 276 identifier in which case an Internet domain socket will be used 277 for the communications, or a valid file name (which shouldn't 278 exist and will be deleted afterwards) in which case a Unix domain 279 socket is created. 280 281 @note Using Internet domain sockets is extremely insecure for IPC as 282 there is absolutely no access control for them, use Unix domain 283 sockets whenever possible! 284 */ 285 wxConnectionBase* MakeConnection(const wxString& host, 286 const wxString& service, 287 const wxString& topic); 288 289 /** 290 Called by MakeConnection(), by default this simply returns a new wxConnection 291 object. Override this method to return a wxConnection descendant customised 292 for the application. 293 294 The advantage of deriving your own connection class is that it will enable 295 you to intercept messages initiated by the server, such as wxConnection::OnAdvise. 296 You may also want to store application-specific data in instances of 297 the new class. 298 */ 299 wxConnectionBase* OnMakeConnection(); 300 301 /** 302 Returns @true if this is a valid host name, @false otherwise. 303 This always returns @true under MS Windows. 304 */ 305 bool ValidHost(const wxString& host); 306 }; 307 308 309 310 /** 311 @class wxServer 312 313 A wxServer object represents the server part of a client-server DDE-like 314 (Dynamic Data Exchange) conversation. The actual DDE-based implementation 315 using wxDDEServer is available on Windows only, but a platform-independent, 316 socket-based version of this API is available using wxTCPServer, which has 317 the same API. 318 319 To create a server which can communicate with a suitable client, you need to 320 derive a class from wxConnection and another from wxServer. 321 The custom wxConnection class will intercept communications in a 'conversation' 322 with a client, and the custom wxServer is required so that a user-overridden 323 wxServer::OnAcceptConnection member can return a wxConnection of the required 324 class, when a connection is made. 325 Look at the IPC sample and the @ref overview_ipc for an example of how to do this. 326 327 @library{wxbase} 328 @category{ipc} 329 330 @see wxClient, wxConnection, IPC, @ref overview_ipc 331 */ 332 class wxServer 333 { 334 public: 335 /** 336 Constructs a server object. 337 */ 338 wxServer(); 339 340 /** 341 Registers the server using the given service name. 342 Under Unix, the service name may be either an integer port identifier in 343 which case an Internet domain socket will be used for the communications, 344 or a valid file name (which shouldn't exist and will be deleted afterwards) 345 in which case a Unix domain socket is created. 346 347 @false is returned if the call failed (for example, the port number is 348 already in use). 349 */ 350 bool Create(const wxString& service); 351 352 /** 353 When a client calls @b MakeConnection, the server receives the 354 message and this member is called. The application should derive a 355 member to intercept this message and return a connection object of 356 either the standard wxConnection type, or (more likely) of a 357 user-derived type. 358 359 If the topic is @b STDIO, the application may wish to refuse the 360 connection. Under UNIX, when a server is created the OnAcceptConnection() 361 message is always sent for standard input and output, but in the context 362 of DDE messages it doesn't make a lot of sense. 363 */ 364 virtual wxConnectionBase* OnAcceptConnection(const wxString& topic); 365 }; 366 367