git.maemo.org Git - presencevnc/blob - libvnc/client_examples/backchannel.c

   1 /* A simple example of an RFB client */
   2
   3 #include <stdio.h>
   4 #include <stdlib.h>
   5 #include <time.h>
   6 #include <errno.h>
   7 #include <rfb/rfbclient.h>
   8
   9 static void HandleRect(rfbClient* client, int x, int y, int w, int h) {
  10 }
  11
  12 /*
  13  * The client part of the back channel extension example.
  14  *
  15  */
  16
  17 #define rfbBackChannel 155
  18
  19 typedef struct backChannelMsg {
  20         uint8_t type;
  21         uint8_t pad1;
  22         uint16_t pad2;
  23         uint32_t size;
  24 } backChannelMsg;
  25
  26 static void sendMessage(rfbClient* client, char* text)
  27 {
  28         backChannelMsg msg;
  29         uint32_t length = strlen(text)+1;
  30
  31         msg.type = rfbBackChannel;
  32         msg.size = rfbClientSwap32IfLE(length);
  33         if(!WriteToRFBServer(client, (char*)&msg, sizeof(msg)) ||
  34                         !WriteToRFBServer(client, text, length)) {
  35                 rfbClientLog("enableBackChannel: write error (%d: %s)", errno, strerror(errno));
  36         }
  37 }
  38
  39 static rfbBool handleBackChannelMessage(rfbClient* client,
  40         rfbServerToClientMsg* message)
  41 {
  42         backChannelMsg msg;
  43         char* text;
  44
  45         if(message->type != rfbBackChannel)
  46                 return FALSE;
  47
  48         rfbClientSetClientData(client, sendMessage, sendMessage);
  49
  50         if(!ReadFromRFBServer(client, ((char*)&msg)+1, sizeof(msg)-1))
  51                 return TRUE;
  52         msg.size = rfbClientSwap32IfLE(msg.size);
  53         text = malloc(msg.size);
  54         if(!ReadFromRFBServer(client, text, msg.size)) {
  55                 free(text);
  56                 return TRUE;
  57         }
  58
  59         rfbClientLog("got back channel message: %s\n", text);
  60         free(text);
  61
  62         return TRUE;
  63 }
  64
  65 static int backChannelEncodings[] = { rfbBackChannel, 0 };
  66
  67 static rfbClientProtocolExtension backChannel = {
  68         backChannelEncodings,           /* encodings */
  69         NULL,                           /* handleEncoding */
  70         handleBackChannelMessage,       /* handleMessage */
  71         NULL                            /* next extension */
  72 };
  73
  74 int
  75 main(int argc, char **argv)
  76 {
  77         rfbClient* client = rfbGetClient(8,3,4);
  78
  79         client->GotFrameBufferUpdate = HandleRect;
  80         rfbClientRegisterExtension(&backChannel);
  81
  82         if (!rfbInitClient(client,&argc,argv))
  83                 return 1;
  84
  85         while (1) {
  86                 /* After each idle second, send a message */
  87                 if(WaitForMessage(client,1000000)>0)
  88                         HandleRFBServerMessage(client);
  89                 else if(rfbClientGetClientData(client, sendMessage))
  90                         sendMessage(client, "Dear Server,\n"
  91                                         "thank you for understanding "
  92                                         "back channel messages!");
  93         }
  94
  95         rfbClientCleanup(client);
  96
  97         return 0;
  98 }
  99