src/common/sckipc.cpp

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        src/common/sckipc.cpp
   3 // Purpose:     Interprocess communication implementation (wxSocket version)
   4 // Author:      Julian Smart
   5 // Modified by: Guilhem Lavaux (big rewrite) May 1997, 1998
   6 //              Guillermo Rodriguez (updated for wxSocket v2) Jan 2000
   7 //                                  (callbacks deprecated)    Mar 2000
   8 //              Vadim Zeitlin (added support for Unix sockets) Apr 2002
   9 //                            (use buffering, many fixes/cleanup) Oct 2008
  10 // Created:     1993
  11 // RCS-ID:      $Id$
  12 // Copyright:   (c) Julian Smart 1993
  13 //              (c) Guilhem Lavaux 1997, 1998
  14 //              (c) 2000 Guillermo Rodriguez <guille@iies.es>
  15 // Licence:     wxWindows licence
  16 /////////////////////////////////////////////////////////////////////////////
  17
  18 // ==========================================================================
  19 // declarations
  20 // ==========================================================================
  21
  22 // --------------------------------------------------------------------------
  23 // headers
  24 // --------------------------------------------------------------------------
  25
  26 // For compilers that support precompilation, includes "wx.h".
  27 #include "wx/wxprec.h"
  28
  29 #ifdef __BORLANDC__
  30     #pragma hdrstop
  31 #endif
  32
  33 #if wxUSE_SOCKETS && wxUSE_IPC && wxUSE_STREAMS
  34
  35 #include "wx/sckipc.h"
  36
  37 #ifndef WX_PRECOMP
  38     #include "wx/log.h"
  39     #include "wx/event.h"
  40     #include "wx/module.h"
  41 #endif
  42
  43 #include <stdlib.h>
  44 #include <stdio.h>
  45 #include <errno.h>
  46
  47 #include "wx/socket.h"
  48
  49 // --------------------------------------------------------------------------
  50 // macros and constants
  51 // --------------------------------------------------------------------------
  52
  53 namespace
  54 {
  55
  56 // Message codes (don't change them to avoid breaking the existing code using
  57 // wxIPC protocol!)
  58 enum IPCCode
  59 {
  60     IPC_EXECUTE         = 1,
  61     IPC_REQUEST         = 2,
  62     IPC_POKE            = 3,
  63     IPC_ADVISE_START    = 4,
  64     IPC_ADVISE_REQUEST  = 5,
  65     IPC_ADVISE          = 6,
  66     IPC_ADVISE_STOP     = 7,
  67     IPC_REQUEST_REPLY   = 8,
  68     IPC_FAIL            = 9,
  69     IPC_CONNECT         = 10,
  70     IPC_DISCONNECT      = 11,
  71     IPC_MAX
  72 };
  73
  74 } // anonymous namespace
  75
  76 // headers needed for umask()
  77 #ifdef __UNIX_LIKE__
  78     #include <sys/types.h>
  79     #include <sys/stat.h>
  80 #endif // __UNIX_LIKE__
  81
  82 // ----------------------------------------------------------------------------
  83 // private functions
  84 // ----------------------------------------------------------------------------
  85
  86 // get the address object for the given server name, the caller must delete it
  87 static wxSockAddress *
  88 GetAddressFromName(const wxString& serverName,
  89                    const wxString& host = wxEmptyString)
  90 {
  91     // we always use INET sockets under non-Unix systems
  92 #if defined(__UNIX__) && !defined(__WINDOWS__) && !defined(__WINE__)
  93     // under Unix, if the server name looks like a path, create a AF_UNIX
  94     // socket instead of AF_INET one
  95     if ( serverName.Find(wxT('/')) != wxNOT_FOUND )
  96     {
  97         wxUNIXaddress *addr = new wxUNIXaddress;
  98         addr->Filename(serverName);
  99
 100         return addr;
 101     }
 102 #endif // Unix/!Unix
 103     {
 104         wxIPV4address *addr = new wxIPV4address;
 105         addr->Service(serverName);
 106         if ( !host.empty() )
 107         {
 108             addr->Hostname(host);
 109         }
 110
 111         return addr;
 112     }
 113 }
 114
 115 // --------------------------------------------------------------------------
 116 // wxTCPEventHandler stuff (private class)
 117 // --------------------------------------------------------------------------
 118
 119 class wxTCPEventHandler : public wxEvtHandler
 120 {
 121 public:
 122     wxTCPEventHandler() : wxEvtHandler() { }
 123
 124     void Client_OnRequest(wxSocketEvent& event);
 125     void Server_OnRequest(wxSocketEvent& event);
 126
 127 private:
 128     void HandleDisconnect(wxTCPConnection *connection);
 129
 130     DECLARE_EVENT_TABLE()
 131     wxDECLARE_NO_COPY_CLASS(wxTCPEventHandler);
 132 };
 133
 134 enum
 135 {
 136     _CLIENT_ONREQUEST_ID = 1000,
 137     _SERVER_ONREQUEST_ID
 138 };
 139
 140 // --------------------------------------------------------------------------
 141 // wxTCPEventHandlerModule (private class)
 142 // --------------------------------------------------------------------------
 143
 144 class wxTCPEventHandlerModule : public wxModule
 145 {
 146 public:
 147     wxTCPEventHandlerModule() : wxModule() { }
 148
 149     // get the global wxTCPEventHandler creating it if necessary
 150     static wxTCPEventHandler& GetHandler()
 151     {
 152         if ( !ms_handler )
 153             ms_handler = new wxTCPEventHandler;
 154
 155         return *ms_handler;
 156     }
 157
 158     // as ms_handler is initialized on demand, don't do anything in OnInit()
 159     virtual bool OnInit() { return true; }
 160     virtual void OnExit() { wxDELETE(ms_handler); }
 161
 162 private:
 163     static wxTCPEventHandler *ms_handler;
 164
 165     DECLARE_DYNAMIC_CLASS(wxTCPEventHandlerModule)
 166     wxDECLARE_NO_COPY_CLASS(wxTCPEventHandlerModule);
 167 };
 168
 169 IMPLEMENT_DYNAMIC_CLASS(wxTCPEventHandlerModule, wxModule)
 170
 171 wxTCPEventHandler *wxTCPEventHandlerModule::ms_handler = NULL;
 172
 173 // --------------------------------------------------------------------------
 174 // wxIPCSocketStreams
 175 // --------------------------------------------------------------------------
 176
 177 #define USE_BUFFER
 178
 179 // this class contains the various (related) streams used by wxTCPConnection
 180 // and also provides a way to read from the socket stream directly
 181 //
 182 // for writing to the stream use the IPCOutput class below
 183 class wxIPCSocketStreams
 184 {
 185 public:
 186     // ctor initializes all the streams on top of the given socket
 187     //
 188     // note that we use a bigger than default buffer size which matches the
 189     // typical Ethernet MTU (minus TCP header overhead)
 190     wxIPCSocketStreams(wxSocketBase& sock)
 191         : m_socketStream(sock),
 192 #ifdef USE_BUFFER
 193           m_bufferedOut(m_socketStream, 1448),
 194 #else
 195           m_bufferedOut(m_socketStream),
 196 #endif
 197           m_dataIn(m_socketStream),
 198           m_dataOut(m_bufferedOut)
 199     {
 200     }
 201
 202     // expose the IO methods needed by IPC code (notice that writing is only
 203     // done via IPCOutput)
 204
 205     // flush output
 206     void Flush()
 207     {
 208 #ifdef USE_BUFFER
 209         m_bufferedOut.Sync();
 210 #endif
 211     }
 212
 213     // simple wrappers around the functions with the same name in
 214     // wxDataInputStream
 215     wxUint8 Read8()
 216     {
 217         Flush();
 218         return m_dataIn.Read8();
 219     }
 220
 221     wxUint32 Read32()
 222     {
 223         Flush();
 224         return m_dataIn.Read32();
 225     }
 226
 227     wxString ReadString()
 228     {
 229         Flush();
 230         return m_dataIn.ReadString();
 231     }
 232
 233     // read arbitrary (size-prepended) data
 234     //
 235     // connection parameter is needed to call its GetBufferAtLeast() method
 236     void *ReadData(wxConnectionBase *conn, size_t *size)
 237     {
 238         Flush();
 239
 240         wxCHECK_MSG( conn, NULL, "NULL connection parameter" );
 241         wxCHECK_MSG( size, NULL, "NULL size parameter" );
 242
 243         *size = Read32();
 244
 245         void * const data = conn->GetBufferAtLeast(*size);
 246         wxCHECK_MSG( data, NULL, "IPC buffer allocation failed" );
 247
 248         m_socketStream.Read(data, *size);
 249
 250         return data;
 251     }
 252
 253     // same as above but for data preceded by the format
 254     void *
 255     ReadFormatData(wxConnectionBase *conn, wxIPCFormat *format, size_t *size)
 256     {
 257         wxCHECK_MSG( format, NULL, "NULL format parameter" );
 258
 259         *format = static_cast<wxIPCFormat>(Read8());
 260
 261         return ReadData(conn, size);
 262     }
 263
 264
 265     // these methods are only used by IPCOutput and not directly
 266     wxDataOutputStream& GetDataOut() { return m_dataOut; }
 267     wxOutputStream& GetUnformattedOut() { return m_bufferedOut; }
 268
 269 private:
 270     // this is the low-level underlying stream using the connection socket
 271     wxSocketStream m_socketStream;
 272
 273     // the buffered stream is used to avoid writing all pieces of an IPC
 274     // request to the socket one by one but to instead do it all at once when
 275     // we're done with it
 276 #ifdef USE_BUFFER
 277     wxBufferedOutputStream m_bufferedOut;
 278 #else
 279     wxOutputStream& m_bufferedOut;
 280 #endif
 281
 282     // finally the data streams are used to be able to write typed data into
 283     // the above streams easily
 284     wxDataInputStream  m_dataIn;
 285     wxDataOutputStream m_dataOut;
 286
 287     wxDECLARE_NO_COPY_CLASS(wxIPCSocketStreams);
 288 };
 289
 290 namespace
 291 {
 292
 293 // an object of this class should be instantiated on the stack to write to the
 294 // underlying socket stream
 295 //
 296 // this class is intentionally separated from wxIPCSocketStreams to ensure that
 297 // Flush() is always called
 298 class IPCOutput
 299 {
 300 public:
 301     // construct an object associated with the given streams (which must have
 302     // life time greater than ours as we keep a reference to it)
 303     IPCOutput(wxIPCSocketStreams *streams)
 304         : m_streams(*streams)
 305     {
 306         wxASSERT_MSG( streams, "NULL streams pointer" );
 307     }
 308
 309     // dtor calls Flush() really sending the IPC data to the network
 310     ~IPCOutput() { m_streams.Flush(); }
 311
 312
 313     // write a byte
 314     void Write8(wxUint8 i)
 315     {
 316         m_streams.GetDataOut().Write8(i);
 317     }
 318
 319     // write the reply code and a string
 320     void Write(IPCCode code, const wxString& str)
 321     {
 322         Write8(code);
 323         m_streams.GetDataOut().WriteString(str);
 324     }
 325
 326     // write the reply code, a string and a format in this order
 327     void Write(IPCCode code, const wxString& str, wxIPCFormat format)
 328     {
 329         Write(code, str);
 330         Write8(format);
 331     }
 332
 333     // write arbitrary data
 334     void WriteData(const void *data, size_t size)
 335     {
 336         m_streams.GetDataOut().Write32(size);
 337         m_streams.GetUnformattedOut().Write(data, size);
 338     }
 339
 340
 341 private:
 342     wxIPCSocketStreams& m_streams;
 343
 344     wxDECLARE_NO_COPY_CLASS(IPCOutput);
 345 };
 346
 347 } // anonymous namespace
 348
 349 // ==========================================================================
 350 // implementation
 351 // ==========================================================================
 352
 353 IMPLEMENT_DYNAMIC_CLASS(wxTCPServer, wxServerBase)
 354 IMPLEMENT_DYNAMIC_CLASS(wxTCPClient, wxClientBase)
 355 IMPLEMENT_CLASS(wxTCPConnection, wxConnectionBase)
 356
 357 // --------------------------------------------------------------------------
 358 // wxTCPClient
 359 // --------------------------------------------------------------------------
 360
 361 wxTCPClient::wxTCPClient()
 362            : wxClientBase()
 363 {
 364 }
 365
 366 bool wxTCPClient::ValidHost(const wxString& host)
 367 {
 368     wxIPV4address addr;
 369
 370     return addr.Hostname(host);
 371 }
 372
 373 wxConnectionBase *wxTCPClient::MakeConnection(const wxString& host,
 374                                               const wxString& serverName,
 375                                               const wxString& topic)
 376 {
 377     wxSockAddress *addr = GetAddressFromName(serverName, host);
 378     if ( !addr )
 379         return NULL;
 380
 381     wxSocketClient * const client = new wxSocketClient(wxSOCKET_WAITALL);
 382     wxIPCSocketStreams * const streams = new wxIPCSocketStreams(*client);
 383
 384     bool ok = client->Connect(*addr);
 385     delete addr;
 386
 387     if ( ok )
 388     {
 389         // Send topic name, and enquire whether this has succeeded
 390         IPCOutput(streams).Write(IPC_CONNECT, topic);
 391
 392         unsigned char msg = streams->Read8();
 393
 394         // OK! Confirmation.
 395         if (msg == IPC_CONNECT)
 396         {
 397             wxTCPConnection *
 398                 connection = (wxTCPConnection *)OnMakeConnection ();
 399
 400             if (connection)
 401             {
 402                 if (wxDynamicCast(connection, wxTCPConnection))
 403                 {
 404                     connection->m_topic = topic;
 405                     connection->m_sock  = client;
 406                     connection->m_streams = streams;
 407                     client->SetEventHandler(wxTCPEventHandlerModule::GetHandler(),
 408                                             _CLIENT_ONREQUEST_ID);
 409                     client->SetClientData(connection);
 410                     client->SetNotify(wxSOCKET_INPUT_FLAG | wxSOCKET_LOST_FLAG);
 411                     client->Notify(true);
 412                     return connection;
 413                 }
 414                 else
 415                 {
 416                     delete connection;
 417                     // and fall through to delete everything else
 418                 }
 419             }
 420         }
 421     }
 422
 423     // Something went wrong, delete everything
 424     delete streams;
 425     client->Destroy();
 426
 427     return NULL;
 428 }
 429
 430 wxConnectionBase *wxTCPClient::OnMakeConnection()
 431 {
 432     return new wxTCPConnection();
 433 }
 434
 435 // --------------------------------------------------------------------------
 436 // wxTCPServer
 437 // --------------------------------------------------------------------------
 438
 439 wxTCPServer::wxTCPServer()
 440            : wxServerBase()
 441 {
 442     m_server = NULL;
 443 }
 444
 445 bool wxTCPServer::Create(const wxString& serverName)
 446 {
 447     // Destroy previous server, if any
 448     if (m_server)
 449     {
 450         m_server->SetClientData(NULL);
 451         m_server->Destroy();
 452         m_server = NULL;
 453     }
 454
 455     wxSockAddress *addr = GetAddressFromName(serverName);
 456     if ( !addr )
 457         return false;
 458
 459 #ifdef __UNIX_LIKE__
 460     mode_t umaskOld;
 461     if ( addr->Type() == wxSockAddress::UNIX )
 462     {
 463         // ensure that the file doesn't exist as otherwise calling socket()
 464         // would fail
 465         int rc = remove(serverName.fn_str());
 466         if ( rc < 0 && errno != ENOENT )
 467         {
 468             delete addr;
 469
 470             return false;
 471         }
 472
 473         // also set the umask to prevent the others from reading our file
 474         umaskOld = umask(077);
 475     }
 476     else
 477     {
 478         // unused anyhow but shut down the compiler warnings
 479         umaskOld = 0;
 480     }
 481 #endif // __UNIX_LIKE__
 482
 483     // Create a socket listening on the specified port (reusing it to allow
 484     // restarting the server listening on the same port as was used by the
 485     // previous instance of this server)
 486     m_server = new wxSocketServer(*addr, wxSOCKET_WAITALL | wxSOCKET_REUSEADDR);
 487
 488 #ifdef __UNIX_LIKE__
 489     if ( addr->Type() == wxSockAddress::UNIX )
 490     {
 491         // restore the umask
 492         umask(umaskOld);
 493
 494         // save the file name to remove it later
 495         m_filename = serverName;
 496     }
 497 #endif // __UNIX_LIKE__
 498
 499     delete addr;
 500
 501     if (!m_server->IsOk())
 502     {
 503         m_server->Destroy();
 504         m_server = NULL;
 505
 506         return false;
 507     }
 508
 509     m_server->SetEventHandler(wxTCPEventHandlerModule::GetHandler(),
 510                               _SERVER_ONREQUEST_ID);
 511     m_server->SetClientData(this);
 512     m_server->SetNotify(wxSOCKET_CONNECTION_FLAG);
 513     m_server->Notify(true);
 514
 515     return true;
 516 }
 517
 518 wxTCPServer::~wxTCPServer()
 519 {
 520     if ( m_server )
 521     {
 522         m_server->SetClientData(NULL);
 523         m_server->Destroy();
 524     }
 525
 526 #ifdef __UNIX_LIKE__
 527     if ( !m_filename.empty() )
 528     {
 529         if ( remove(m_filename.fn_str()) != 0 )
 530         {
 531             wxLogDebug(wxT("Stale AF_UNIX file '%s' left."), m_filename.c_str());
 532         }
 533     }
 534 #endif // __UNIX_LIKE__
 535 }
 536
 537 wxConnectionBase *
 538 wxTCPServer::OnAcceptConnection(const wxString& WXUNUSED(topic))
 539 {
 540     return new wxTCPConnection();
 541 }
 542
 543 // --------------------------------------------------------------------------
 544 // wxTCPConnection
 545 // --------------------------------------------------------------------------
 546
 547 void wxTCPConnection::Init()
 548 {
 549     m_sock = NULL;
 550     m_streams = NULL;
 551 }
 552
 553 wxTCPConnection::~wxTCPConnection()
 554 {
 555     Disconnect();
 556
 557     if ( m_sock )
 558     {
 559         m_sock->SetClientData(NULL);
 560         m_sock->Destroy();
 561     }
 562
 563     delete m_streams;
 564 }
 565
 566 void wxTCPConnection::Compress(bool WXUNUSED(on))
 567 {
 568     // TODO
 569 }
 570
 571 // Calls that CLIENT can make.
 572 bool wxTCPConnection::Disconnect()
 573 {
 574     if ( !GetConnected() )
 575         return true;
 576
 577     // Send the disconnect message to the peer.
 578     IPCOutput(m_streams).Write8(IPC_DISCONNECT);
 579
 580     if ( m_sock )
 581     {
 582         m_sock->Notify(false);
 583         m_sock->Close();
 584     }
 585
 586     SetConnected(false);
 587
 588     return true;
 589 }
 590
 591 bool wxTCPConnection::DoExecute(const void *data,
 592                                 size_t size,
 593                                 wxIPCFormat format)
 594 {
 595     if ( !m_sock->IsConnected() )
 596         return false;
 597
 598     // Prepare EXECUTE message
 599     IPCOutput out(m_streams);
 600     out.Write8(IPC_EXECUTE);
 601     out.Write8(format);
 602
 603     out.WriteData(data, size);
 604
 605     return true;
 606 }
 607
 608 const void *wxTCPConnection::Request(const wxString& item,
 609                                      size_t *size,
 610                                      wxIPCFormat format)
 611 {
 612     if ( !m_sock->IsConnected() )
 613         return NULL;
 614
 615     IPCOutput(m_streams).Write(IPC_REQUEST, item, format);
 616
 617     const int ret = m_streams->Read8();
 618     if ( ret != IPC_REQUEST_REPLY )
 619         return NULL;
 620
 621     // ReadData() needs a non-NULL size pointer but the client code can call us
 622     // with NULL pointer (this makes sense if it knows that it always works
 623     // with NUL-terminated strings)
 624     size_t sizeFallback;
 625     return m_streams->ReadData(this, size ? size : &sizeFallback);
 626 }
 627
 628 bool wxTCPConnection::DoPoke(const wxString& item,
 629                              const void *data,
 630                              size_t size,
 631                              wxIPCFormat format)
 632 {
 633     if ( !m_sock->IsConnected() )
 634         return false;
 635
 636     IPCOutput out(m_streams);
 637     out.Write(IPC_POKE, item, format);
 638     out.WriteData(data, size);
 639
 640     return true;
 641 }
 642
 643 bool wxTCPConnection::StartAdvise(const wxString& item)
 644 {
 645     if ( !m_sock->IsConnected() )
 646         return false;
 647
 648     IPCOutput(m_streams).Write(IPC_ADVISE_START, item);
 649
 650     const int ret = m_streams->Read8();
 651
 652     return ret == IPC_ADVISE_START;
 653 }
 654
 655 bool wxTCPConnection::StopAdvise (const wxString& item)
 656 {
 657     if ( !m_sock->IsConnected() )
 658         return false;
 659
 660     IPCOutput(m_streams).Write(IPC_ADVISE_STOP, item);
 661
 662     const int ret = m_streams->Read8();
 663
 664     return ret == IPC_ADVISE_STOP;
 665 }
 666
 667 // Calls that SERVER can make
 668 bool wxTCPConnection::DoAdvise(const wxString& item,
 669                                const void *data,
 670                                size_t size,
 671                                wxIPCFormat format)
 672 {
 673     if ( !m_sock->IsConnected() )
 674         return false;
 675
 676     IPCOutput out(m_streams);
 677     out.Write(IPC_ADVISE, item, format);
 678     out.WriteData(data, size);
 679
 680     return true;
 681 }
 682
 683 // --------------------------------------------------------------------------
 684 // wxTCPEventHandler (private class)
 685 // --------------------------------------------------------------------------
 686
 687 BEGIN_EVENT_TABLE(wxTCPEventHandler, wxEvtHandler)
 688     EVT_SOCKET(_CLIENT_ONREQUEST_ID, wxTCPEventHandler::Client_OnRequest)
 689     EVT_SOCKET(_SERVER_ONREQUEST_ID, wxTCPEventHandler::Server_OnRequest)
 690 END_EVENT_TABLE()
 691
 692 void wxTCPEventHandler::HandleDisconnect(wxTCPConnection *connection)
 693 {
 694     // connection was closed (either gracefully or not): destroy everything
 695     connection->m_sock->Notify(false);
 696     connection->m_sock->Close();
 697
 698     // don't leave references to this soon-to-be-dangling connection in the
 699     // socket as it won't be destroyed immediately as its destruction will be
 700     // delayed in case there are more events pending for it
 701     connection->m_sock->SetClientData(NULL);
 702
 703     connection->SetConnected(false);
 704     connection->OnDisconnect();
 705 }
 706
 707 void wxTCPEventHandler::Client_OnRequest(wxSocketEvent &event)
 708 {
 709     wxSocketBase *sock = event.GetSocket();
 710     if (!sock)
 711         return;
 712
 713     wxSocketNotify evt = event.GetSocketEvent();
 714     wxTCPConnection * const
 715         connection = static_cast<wxTCPConnection *>(sock->GetClientData());
 716
 717     // This socket is being deleted; skip this event
 718     if (!connection)
 719         return;
 720
 721     if ( evt == wxSOCKET_LOST )
 722     {
 723         HandleDisconnect(connection);
 724         return;
 725     }
 726
 727     // Receive message number.
 728     wxIPCSocketStreams * const streams = connection->m_streams;
 729
 730     const wxString topic = connection->m_topic;
 731     wxString item;
 732
 733     bool error = false;
 734
 735     const int msg = streams->Read8();
 736     switch ( msg )
 737     {
 738         case IPC_EXECUTE:
 739             {
 740                 wxIPCFormat format;
 741                 size_t size wxDUMMY_INITIALIZE(0);
 742                 void * const
 743                     data = streams->ReadFormatData(connection, &format, &size);
 744                 if ( data )
 745                     connection->OnExecute(topic, data, size, format);
 746                 else
 747                     error = true;
 748             }
 749             break;
 750
 751         case IPC_ADVISE:
 752             {
 753                 item = streams->ReadString();
 754
 755                 wxIPCFormat format;
 756                 size_t size wxDUMMY_INITIALIZE(0);
 757                 void * const
 758                     data = streams->ReadFormatData(connection, &format, &size);
 759
 760                 if ( data )
 761                     connection->OnAdvise(topic, item, data, size, format);
 762                 else
 763                     error = true;
 764             }
 765             break;
 766
 767         case IPC_ADVISE_START:
 768             {
 769                 item = streams->ReadString();
 770
 771                 IPCOutput(streams).Write8(connection->OnStartAdvise(topic, item)
 772                                             ? IPC_ADVISE_START
 773                                             : IPC_FAIL);
 774             }
 775             break;
 776
 777         case IPC_ADVISE_STOP:
 778             {
 779                 item = streams->ReadString();
 780
 781                 IPCOutput(streams).Write8(connection->OnStopAdvise(topic, item)
 782                                              ? IPC_ADVISE_STOP
 783                                              : IPC_FAIL);
 784             }
 785             break;
 786
 787         case IPC_POKE:
 788             {
 789                 item = streams->ReadString();
 790                 wxIPCFormat format = (wxIPCFormat)streams->Read8();
 791
 792                 size_t size wxDUMMY_INITIALIZE(0);
 793                 void * const data = streams->ReadData(connection, &size);
 794
 795                 if ( data )
 796                     connection->OnPoke(topic, item, data, size, format);
 797                 else
 798                     error = true;
 799             }
 800             break;
 801
 802         case IPC_REQUEST:
 803             {
 804                 item = streams->ReadString();
 805
 806                 wxIPCFormat format = (wxIPCFormat)streams->Read8();
 807
 808                 size_t user_size = wxNO_LEN;
 809                 const void *user_data = connection->OnRequest(topic,
 810                                                               item,
 811                                                               &user_size,
 812                                                               format);
 813
 814                 if ( !user_data )
 815                 {
 816                     IPCOutput(streams).Write8(IPC_FAIL);
 817                     break;
 818                 }
 819
 820                 IPCOutput out(streams);
 821                 out.Write8(IPC_REQUEST_REPLY);
 822
 823                 if ( user_size == wxNO_LEN )
 824                 {
 825                     switch ( format )
 826                     {
 827                         case wxIPC_TEXT:
 828                         case wxIPC_UTF8TEXT:
 829                             user_size = strlen((const char *)user_data) + 1;  // includes final NUL
 830                             break;
 831                         case wxIPC_UNICODETEXT:
 832                             user_size = (wcslen((const wchar_t *)user_data) + 1) * sizeof(wchar_t);  // includes final NUL
 833                             break;
 834                         default:
 835                             user_size = 0;
 836                     }
 837                 }
 838
 839                 out.WriteData(user_data, user_size);
 840             }
 841             break;
 842
 843         case IPC_DISCONNECT:
 844             HandleDisconnect(connection);
 845             break;
 846
 847         case IPC_FAIL:
 848             wxLogDebug("Unexpected IPC_FAIL received");
 849             error = true;
 850             break;
 851
 852         default:
 853             wxLogDebug("Unknown message code %d received.", msg);
 854             error = true;
 855             break;
 856     }
 857
 858     if ( error )
 859         IPCOutput(streams).Write8(IPC_FAIL);
 860 }
 861
 862 void wxTCPEventHandler::Server_OnRequest(wxSocketEvent &event)
 863 {
 864     wxSocketServer *server = (wxSocketServer *) event.GetSocket();
 865     if (!server)
 866         return;
 867     wxTCPServer *ipcserv = (wxTCPServer *) server->GetClientData();
 868
 869     // This socket is being deleted; skip this event
 870     if (!ipcserv)
 871         return;
 872
 873     if (event.GetSocketEvent() != wxSOCKET_CONNECTION)
 874         return;
 875
 876     // Accept the connection, getting a new socket
 877     wxSocketBase *sock = server->Accept();
 878     if (!sock)
 879         return;
 880     if (!sock->IsOk())
 881     {
 882         sock->Destroy();
 883         return;
 884     }
 885
 886     wxIPCSocketStreams *streams = new wxIPCSocketStreams(*sock);
 887
 888     {
 889         IPCOutput out(streams);
 890
 891         const int msg = streams->Read8();
 892         if ( msg == IPC_CONNECT )
 893         {
 894             const wxString topic = streams->ReadString();
 895
 896             wxTCPConnection *new_connection =
 897                 (wxTCPConnection *)ipcserv->OnAcceptConnection (topic);
 898
 899             if (new_connection)
 900             {
 901                 if (wxDynamicCast(new_connection, wxTCPConnection))
 902                 {
 903                     // Acknowledge success
 904                     out.Write8(IPC_CONNECT);
 905
 906                     new_connection->m_sock = sock;
 907                     new_connection->m_streams = streams;
 908                     new_connection->m_topic = topic;
 909                     sock->SetEventHandler(wxTCPEventHandlerModule::GetHandler(),
 910                                           _CLIENT_ONREQUEST_ID);
 911                     sock->SetClientData(new_connection);
 912                     sock->SetNotify(wxSOCKET_INPUT_FLAG | wxSOCKET_LOST_FLAG);
 913                     sock->Notify(true);
 914                     return;
 915                 }
 916                 else
 917                 {
 918                     delete new_connection;
 919                     // and fall through to delete everything else
 920                 }
 921             }
 922         }
 923
 924         // Something went wrong, send failure message and delete everything
 925         out.Write8(IPC_FAIL);
 926     } // IPCOutput object is destroyed here, before destroying stream
 927
 928     delete streams;
 929     sock->Destroy();
 930 }
 931
 932 #endif // wxUSE_SOCKETS && wxUSE_IPC && wxUSE_STREAMS