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      1 /**
      2  * @example backchannel-client.c
      3  * A simple example of an RFB client
      4  */
      5 
      6 #include <stdio.h>
      7 #include <stdlib.h>
      8 #include <time.h>
      9 #include <errno.h>
     10 #include <rfb/rfbclient.h>
     11 
     12 static void HandleRect(rfbClient* client, int x, int y, int w, int h) {
     13 }
     14 
     15 /*
     16  * The client part of the back channel extension example.
     17  *
     18  */
     19 
     20 #define rfbBackChannel 155
     21 
     22 typedef struct backChannelMsg {
     23         uint8_t type;
     24         uint8_t pad1;
     25         uint16_t pad2;
     26         uint32_t size;
     27 } backChannelMsg;
     28 
     29 static void sendMessage(rfbClient* client, char* text)
     30 {
     31 	backChannelMsg msg;
     32 	uint32_t length = strlen(text)+1;
     33 
     34 	msg.type = rfbBackChannel;
     35 	msg.size = rfbClientSwap32IfLE(length);
     36 	if(!WriteToRFBServer(client, (char*)&msg, sizeof(msg)) ||
     37 			!WriteToRFBServer(client, text, length)) {
     38 		rfbClientLog("enableBackChannel: write error (%d: %s)", errno, strerror(errno));
     39 	}
     40 }
     41 
     42 static rfbBool handleBackChannelMessage(rfbClient* client,
     43 	rfbServerToClientMsg* message)
     44 {
     45 	backChannelMsg msg;
     46 	char* text;
     47 
     48 	if(message->type != rfbBackChannel)
     49 		return FALSE;
     50 
     51 	rfbClientSetClientData(client, sendMessage, sendMessage);
     52 
     53 	if(!ReadFromRFBServer(client, ((char*)&msg)+1, sizeof(msg)-1))
     54 		return TRUE;
     55 	msg.size = rfbClientSwap32IfLE(msg.size);
     56 	text = malloc(msg.size);
     57 	if(!ReadFromRFBServer(client, text, msg.size)) {
     58 		free(text);
     59 		return TRUE;
     60 	}
     61 
     62 	rfbClientLog("got back channel message: %s\n", text);
     63 	free(text);
     64 
     65 	return TRUE;
     66 }
     67 
     68 static int backChannelEncodings[] = { rfbBackChannel, 0 };
     69 
     70 static rfbClientProtocolExtension backChannel = {
     71 	backChannelEncodings,		/* encodings */
     72 	NULL,				/* handleEncoding */
     73 	handleBackChannelMessage,	/* handleMessage */
     74 	NULL				/* next extension */
     75 };
     76 
     77 int
     78 main(int argc, char **argv)
     79 {
     80 	rfbClient* client = rfbGetClient(8,3,4);
     81 
     82 	client->GotFrameBufferUpdate = HandleRect;
     83 	rfbClientRegisterExtension(&backChannel);
     84 
     85 	if (!rfbInitClient(client,&argc,argv))
     86 		return 1;
     87 
     88 	while (1) {
     89 		/* After each idle second, send a message */
     90 		if(WaitForMessage(client,1000000)>0)
     91 			HandleRFBServerMessage(client);
     92 		else if(rfbClientGetClientData(client, sendMessage))
     93 			sendMessage(client, "Dear Server,\n"
     94 					"thank you for understanding "
     95 					"back channel messages!");
     96 	}
     97 
     98 	rfbClientCleanup(client);
     99 
    100 	return 0;
    101 }
    102 
    103