3 files changed, 103 insertions, 4 deletions

diff --git a/client_examples/Makefile.am b/client_examples/Makefile.am
index 6ffcf51..77998f0 100644
--- a/client_examples/Makefile.am
+++ b/client_examples/Makefile.am
@@ -23,7 +23,7 @@ SDLvncviewer_CFLAGS=$(SDL_CFLAGS)
 SDLvncviewer_LDADD=$(LDADD) $(SDL_LIBS)
 endif
 
-noinst_PROGRAMS=ppmtest $(SDLVIEWER) $(FFMPEG_CLIENT)
+noinst_PROGRAMS=ppmtest $(SDLVIEWER) $(FFMPEG_CLIENT) backchannel
 
 
 
diff --git a/client_examples/SDLvncviewer.c b/client_examples/SDLvncviewer.c
index 07d3869..8375ea6 100644
--- a/client_examples/SDLvncviewer.c
+++ b/client_examples/SDLvncviewer.c
@@ -16,7 +16,7 @@ static rfbBool resize(rfbClient* client) {
 			okay=SDL_VideoModeOK(width,height,depth,flags);
 	if(okay) {
 		SDL_Surface* sdl=SDL_SetVideoMode(width,height,depth,flags);
-		client->clientData=sdl;
+		rfbClientSetClientData(client, SDL_Init, sdl);
 		client->frameBuffer=sdl->pixels;
 		if(first || depth!=client->format.bitsPerPixel) {
 			first=FALSE;
@@ -30,7 +30,7 @@ static rfbBool resize(rfbClient* client) {
 			SetFormatAndEncodings(client);
 		}
 	} else {
-		SDL_Surface* sdl=client->clientData;
+		SDL_Surface* sdl=rfbClientGetClientData(client, SDL_Init);
 		rfbClientLog("Could not set resolution %dx%d!\n",
 				client->width,client->height);
 		if(sdl) {
@@ -188,7 +188,7 @@ static rfbKeySym SDL_keysym2rfbKeySym(int keysym) {
 }
 
 static void update(rfbClient* cl,int x,int y,int w,int h) {
-	SDL_UpdateRect(cl->clientData, x, y, w, h);
+	SDL_UpdateRect(rfbClientGetClientData(cl, SDL_Init), x, y, w, h);
 }
 
 #ifdef __MINGW32__
diff --git a/client_examples/backchannel.c b/client_examples/backchannel.c
new file mode 100644
index 0000000..643754e
--- /dev/null
+++ b/client_examples/backchannel.c
@@ -0,0 +1,99 @@
+/* A simple example of an RFB client */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+#include <errno.h>
+#include <rfb/rfbclient.h>
+
+static void HandleRect(rfbClient* client, int x, int y, int w, int h) {
+}
+
+/*
+ * The client part of the back channel extension example.
+ *
+ */
+
+#define rfbBackChannel 155
+
+typedef struct backChannelMsg {
+        uint8_t type;
+        uint8_t pad1;
+        uint16_t pad2;
+        uint32_t size;
+} backChannelMsg;
+
+static void sendMessage(rfbClient* client, char* text)
+{
+	backChannelMsg msg;
+	uint32_t length = strlen(text)+1;
+
+	msg.type = rfbBackChannel;
+	msg.size = rfbClientSwap32IfLE(length);
+	if(!WriteToRFBServer(client, (char*)&msg, sizeof(msg)) ||
+			!WriteToRFBServer(client, text, length)) {
+		rfbClientLog("enableBackChannel: write error (%d: %s)", errno, strerror(errno));
+	}
+}
+
+static rfbBool handleBackChannelMessage(rfbClient* client,
+	rfbServerToClientMsg* message)
+{
+	backChannelMsg msg;
+	char* text;
+
+	if(message->type != rfbBackChannel)
+		return FALSE;
+
+	rfbClientSetClientData(client, sendMessage, sendMessage);
+
+	if(!ReadFromRFBServer(client, ((char*)&msg)+1, sizeof(msg)-1))
+		return TRUE;
+	msg.size = rfbClientSwap32IfLE(msg.size);
+	text = malloc(msg.size);
+	if(!ReadFromRFBServer(client, text, msg.size)) {
+		free(text);
+		return TRUE;
+	}
+
+	rfbClientLog("got back channel message: %s\n", text);
+	free(text);
+
+	return TRUE;
+}
+
+static int backChannelEncodings[] = { rfbBackChannel, 0 };
+
+static rfbClientProtocolExtension backChannel = {
+	backChannelEncodings,		/* encodings */
+	NULL,				/* handleEncoding */
+	handleBackChannelMessage,	/* handleMessage */
+	NULL				/* next extension */
+};
+
+int
+main(int argc, char **argv)
+{
+	rfbClient* client = rfbGetClient(8,3,4);
+
+	client->GotFrameBufferUpdate = HandleRect;
+	rfbClientRegisterExtension(&backChannel);
+
+	if (!rfbInitClient(client,&argc,argv))
+		return 1;
+
+	while (1) {
+		/* After each idle second, send a message */
+		if(WaitForMessage(client,1000000)>0)
+			HandleRFBServerMessage(client);
+		else if(rfbClientGetClientData(client, sendMessage))
+			sendMessage(client, "Dear Server,\n"
+					"thank you for understanding "
+					"back channel messages!");
+	}
+
+	rfbClientCleanup(client);
+
+	return 0;
+}
+