Xvnc: support ExtendedMouseButtons pseudo-encoding

This commit contains work originally done by manny33:
  * #1711

This commit adds support for the pseudo-encoding ExtendedMouseButtons in
Xvnc, which makes it possible to use to use the back/forward mouse
buttons.

The back/forward buttons are mapped to the X11 button labels
BTN_LABEL_PROP_BTN_SIDE and BTN_LABEL_PROP_BTN_EXTRA respectively. These
seems to be used more widely both by mice with extra side buttons, as
well as X applications to incidate a back/forward navigation.

There are two other labels:
  BTN_LABEL_PROP_BTN_BACK,
  BTN_LABEL_PROP_BTN_EXTRA,
which some applications listen to as well. But from what I've seen, the
applications that listen to these two labels also listen to SIDE/EXTRA
as well.

common/rfb/CMsgWriter.cxx

@@ -173,7 +173,7 @@ void CMsgWriter::writeKeyEvent(uint32_t keysym, uint32_t keycode, bool down)
 }
 
 
-void CMsgWriter::writePointerEvent(const Point& pos, uint8_t buttonMask)
+void CMsgWriter::writePointerEvent(const Point& pos, uint16_t buttonMask)
 {
   Point p(pos);
   if (p.x < 0) p.x = 0;

common/rfb/CMsgWriter.h

@@ -54,7 +54,7 @@ namespace rfb {
     void writeFence(uint32_t flags, unsigned len, const uint8_t data[]);
 
     void writeKeyEvent(uint32_t keysym, uint32_t keycode, bool down);
-    void writePointerEvent(const Point& pos, uint8_t buttonMask);
+    void writePointerEvent(const Point& pos, uint16_t buttonMask);
 
     void writeClientCutText(const char* str);
 

common/rfb/ClientParams.cxx

@@ -228,3 +228,10 @@ bool ClientParams::supportsContinuousUpdates() const
     return true;
   return false;
 }
+
+bool ClientParams::supportsExtendedMouseButtons() const
+{
+  if (supportsEncoding(pseudoEncodingExtendedMouseButtons))
+    return true;
+  return false;
+}

common/rfb/ClientParams.h

@@ -101,6 +101,7 @@ namespace rfb {
     bool supportsLEDState() const;
     bool supportsFence() const;
     bool supportsContinuousUpdates() const;
+    bool supportsExtendedMouseButtons() const;
 
     int compressLevel;
     int qualityLevel;

common/rfb/SConnection.cxx

@@ -433,6 +433,11 @@ void SConnection::supportsQEMUKeyEvent()
   writer()->writeQEMUKeyEvent();
 }
 
+void SConnection::supportsExtendedMouseButtons()
+{
+  writer()->writeExtendedMouseButtonsSupport();
+}
+
 void SConnection::versionReceived()
 {
 }

common/rfb/SConnection.h

@@ -98,6 +98,8 @@ namespace rfb {
 
     void supportsQEMUKeyEvent() override;
 
+    virtual void supportsExtendedMouseButtons() override;
+
 
     // Methods to be overridden in a derived class
 

common/rfb/SDesktop.h

@@ -98,7 +98,7 @@ namespace rfb {
     // pointerEvent() is called whenever a client sends an event that
     // the pointer moved, or a button was pressed or released.
     virtual void pointerEvent(const Point& /*pos*/,
-                              uint8_t /*buttonMask*/) {};
+                              uint16_t /*buttonMask*/) {};
 
     // handleClipboardRequest() is called whenever a client requests
     // the server to send over its clipboard data. It will only be

common/rfb/SMsgHandler.cxx

@@ -53,12 +53,13 @@ void SMsgHandler::setPixelFormat(const PixelFormat& pf)
 void SMsgHandler::setEncodings(int nEncodings, const int32_t* encodings)
 {
   bool firstFence, firstContinuousUpdates, firstLEDState,
-       firstQEMUKeyEvent;
+       firstQEMUKeyEvent, firstExtMouseButtonsEvent;
 
   firstFence = !client.supportsFence();
   firstContinuousUpdates = !client.supportsContinuousUpdates();
   firstLEDState = !client.supportsLEDState();
   firstQEMUKeyEvent = !client.supportsEncoding(pseudoEncodingQEMUKeyEvent);
+  firstExtMouseButtonsEvent = !client.supportsEncoding(pseudoEncodingExtendedMouseButtons);
 
   client.setEncodings(nEncodings, encodings);
 
@@ -72,6 +73,8 @@ void SMsgHandler::setEncodings(int nEncodings, const int32_t* encodings)
     supportsLEDState();
   if (client.supportsEncoding(pseudoEncodingQEMUKeyEvent) && firstQEMUKeyEvent)
     supportsQEMUKeyEvent();
+  if (client.supportsEncoding(pseudoEncodingExtendedMouseButtons) && firstExtMouseButtonsEvent)
+    supportsExtendedMouseButtons();
 }
 
 void SMsgHandler::keyEvent(uint32_t /*keysym*/, uint32_t /*keycode*/,
@@ -80,7 +83,7 @@ void SMsgHandler::keyEvent(uint32_t /*keysym*/, uint32_t /*keycode*/,
 }
 
 void SMsgHandler::pointerEvent(const Point& /*pos*/,
-                               uint8_t /*buttonMask*/)
+                               uint16_t /*buttonMask*/)
 {
 }
 
@@ -167,3 +170,7 @@ void SMsgHandler::supportsLEDState()
 void SMsgHandler::supportsQEMUKeyEvent()
 {
 }
+
+void SMsgHandler::supportsExtendedMouseButtons()
+{
+}

common/rfb/SMsgHandler.h

@@ -57,7 +57,7 @@ namespace rfb {
     virtual void keyEvent(uint32_t keysym, uint32_t keycode,
                           bool down);
     virtual void pointerEvent(const Point& pos,
-                              uint8_t buttonMask);
+                              uint16_t buttonMask);
 
     virtual void clientCutText(const char* str);
 
@@ -98,6 +98,11 @@ namespace rfb {
     // handler will send a pseudo-rect back, signalling server support.
     virtual void supportsQEMUKeyEvent();
 
+    // supportsExtendedMouseButtons() is called the first time we detect that the
+    // client supports sending 16 bit mouse button state. This lets us pass more button
+    // states between server and client.
+    virtual void supportsExtendedMouseButtons();
+
     ClientParams client;
   };
 }

common/rfb/SMsgReader.cxx

@@ -272,11 +272,32 @@ bool SMsgReader::readKeyEvent()
 
 bool SMsgReader::readPointerEvent()
 {
+  int mask;
+  int x;
+  int y;
+
   if (!is->hasData(1 + 2 + 2))
     return false;
-  int mask = is->readU8();
-  int x = is->readU16();
-  int y = is->readU16();
+
+  is->setRestorePoint();
+
+  mask = is->readU8();
+  x = is->readU16();
+  y = is->readU16();
+
+  if (handler->client.supportsExtendedMouseButtons() && mask & 0x180 ) {
+    int highBits;
+    int lowBits;
+
+    if (!is->hasDataOrRestore(1))
+      return false;
+
+    highBits = is->readU8();
+    lowBits = mask & 0x7f; // Clear marker bit
+    mask = (highBits << 7) | lowBits;
+  }
+
+  is->clearRestorePoint();
   handler->pointerEvent(Point(x, y), mask);
   return true;
 }

common/rfb/SMsgWriter.cxx

@@ -49,7 +49,7 @@ SMsgWriter::SMsgWriter(ClientParams* client_, rdr::OutStream* os_)
     nRectsInUpdate(0), nRectsInHeader(0),
     needSetDesktopName(false), needCursor(false),
     needCursorPos(false), needLEDState(false),
-    needQEMUKeyEvent(false)
+    needQEMUKeyEvent(false), needExtMouseButtonsEvent(false)
 {
 }
 
@@ -303,6 +303,14 @@ void SMsgWriter::writeQEMUKeyEvent()
   needQEMUKeyEvent = true;
 }
 
+void SMsgWriter::writeExtendedMouseButtonsSupport()
+{
+  if (!client->supportsEncoding(pseudoEncodingExtendedMouseButtons))
+    throw Exception("Client does not support Extended Mouse Buttons");
+
+  needExtMouseButtonsEvent = true;
+}
+
 bool SMsgWriter::needFakeUpdate()
 {
   if (needSetDesktopName)
@@ -315,6 +323,8 @@ bool SMsgWriter::needFakeUpdate()
     return true;
   if (needQEMUKeyEvent)
     return true;
+  if (needExtMouseButtonsEvent)
+    return true;
   if (needNoDataUpdate())
     return true;
 
@@ -363,6 +373,8 @@ void SMsgWriter::writeFramebufferUpdateStart(int nRects)
       nRects++;
     if (needQEMUKeyEvent)
       nRects++;
+    if (needExtMouseButtonsEvent)
+      nRects++;
   }
 
   os->writeU16(nRects);
@@ -502,6 +514,11 @@ void SMsgWriter::writePseudoRects()
     writeQEMUKeyEventRect();
     needQEMUKeyEvent = false;
   }
+
+  if (needExtMouseButtonsEvent) {
+    writeExtendedMouseButtonsRect();
+    needExtMouseButtonsEvent = false;
+  }
 }
 
 void SMsgWriter::writeNoDataRects()
@@ -734,3 +751,17 @@ void SMsgWriter::writeQEMUKeyEventRect()
   os->writeU16(0);
   os->writeU32(pseudoEncodingQEMUKeyEvent);
 }
+
+void SMsgWriter::writeExtendedMouseButtonsRect()
+{
+  if (!client->supportsEncoding(pseudoEncodingExtendedMouseButtons))
+    throw Exception("Client does not support extended mouse button events");
+  if (++nRectsInUpdate > nRectsInHeader && nRectsInHeader)
+    throw Exception("SMsgWriter::writeExtendedMouseButtonsRect: nRects out of sync");
+
+  os->writeS16(0);
+  os->writeS16(0);
+  os->writeU16(0);
+  os->writeU16(0);
+  os->writeU32(pseudoEncodingExtendedMouseButtons);
+}

common/rfb/SMsgWriter.h

@@ -93,6 +93,9 @@ namespace rfb {
     // And QEMU keyboard event handshake
     void writeQEMUKeyEvent();
 
+    // let the client know we support extended mouse button support
+    void writeExtendedMouseButtonsSupport();
+
     // needFakeUpdate() returns true when an immediate update is needed in
     // order to flush out pseudo-rectangles to the client.
     bool needFakeUpdate();
@@ -148,6 +151,7 @@ namespace rfb {
     void writeSetVMwareCursorPositionRect(int hotspotX, int hotspotY);
     void writeLEDStateRect(uint8_t state);
     void writeQEMUKeyEventRect();
+    void writeExtendedMouseButtonsRect();
 
     ClientParams* client;
     rdr::OutStream* os;
@@ -160,6 +164,7 @@ namespace rfb {
     bool needCursorPos;
     bool needLEDState;
     bool needQEMUKeyEvent;
+    bool needExtMouseButtonsEvent;
 
     typedef struct {
       uint16_t reason, result;

common/rfb/VNCSConnectionST.cxx

@@ -477,7 +477,7 @@ void VNCSConnectionST::setPixelFormat(const PixelFormat& pf)
   setCursor();
 }
 
-void VNCSConnectionST::pointerEvent(const Point& pos, uint8_t buttonMask)
+void VNCSConnectionST::pointerEvent(const Point& pos, uint16_t buttonMask)
 {
   if (rfb::Server::idleTimeout)
     idleTimer.start(secsToMillis(rfb::Server::idleTimeout));

common/rfb/VNCSConnectionST.h

@@ -123,7 +123,7 @@ namespace rfb {
     void queryConnection(const char* userName) override;
     void clientInit(bool shared) override;
     void setPixelFormat(const PixelFormat& pf) override;
-    void pointerEvent(const Point& pos, uint8_t buttonMask) override;
+    void pointerEvent(const Point& pos, uint16_t buttonMask) override;
     void keyEvent(uint32_t keysym, uint32_t keycode,
                   bool down) override;
     void framebufferUpdateRequest(const Rect& r,

common/rfb/VNCServerST.cxx

@@ -482,7 +482,7 @@ void VNCServerST::keyEvent(uint32_t keysym, uint32_t keycode, bool down)
 }
 
 void VNCServerST::pointerEvent(VNCSConnectionST* client,
-                               const Point& pos, uint8_t buttonMask)
+                               const Point& pos, uint16_t buttonMask)
 {
   time_t now = time(nullptr);
   if (rfb::Server::maxIdleTime)

common/rfb/VNCServerST.h

@@ -117,7 +117,7 @@ namespace rfb {
 
     // Event handlers
     void keyEvent(uint32_t keysym, uint32_t keycode, bool down);
-    void pointerEvent(VNCSConnectionST* client, const Point& pos, uint8_t buttonMask);
+    void pointerEvent(VNCSConnectionST* client, const Point& pos, uint16_t buttonMask);
 
     void handleClipboardRequest(VNCSConnectionST* client);
     void handleClipboardAnnounce(VNCSConnectionST* client, bool available);

common/rfb/encodings.h

@@ -36,6 +36,7 @@ namespace rfb {
 
   const int pseudoEncodingXCursor = -240;
   const int pseudoEncodingCursor = -239;
+  const int pseudoEncodingExtendedMouseButtons = -316;
   const int pseudoEncodingDesktopSize = -223;
   const int pseudoEncodingLEDState = -261;
   const int pseudoEncodingExtendedDesktopSize = -308;

unix/x0vncserver/XDesktop.cxx

@@ -342,7 +342,7 @@ void XDesktop::queryConnection(network::Socket* sock,
   queryConnectDialog->map();
 }
 
-void XDesktop::pointerEvent(const Point& pos, uint8_t buttonMask) {
+void XDesktop::pointerEvent(const Point& pos, uint16_t buttonMask) {
 #ifdef HAVE_XTEST
   if (!haveXtest) return;
   XTestFakeMotionEvent(dpy, DefaultScreen(dpy),

unix/x0vncserver/XDesktop.h

@@ -60,7 +60,7 @@ class XDesktop : public rfb::SDesktop,
   bool isRunning();
   void queryConnection(network::Socket* sock,
                        const char* userName) override;
-  void pointerEvent(const rfb::Point& pos, uint8_t buttonMask) override;
+  void pointerEvent(const rfb::Point& pos, uint16_t buttonMask) override;
   void keyEvent(uint32_t keysym, uint32_t xtcode, bool down) override;
   unsigned int setScreenLayout(int fb_width, int fb_height,
                                const rfb::ScreenSet& layout) override;

unix/xserver/hw/vnc/XserverDesktop.cc

@@ -463,7 +463,7 @@ void XserverDesktop::terminate()
   kill(getpid(), SIGTERM);
 }
 
-void XserverDesktop::pointerEvent(const Point& pos, uint8_t buttonMask)
+void XserverDesktop::pointerEvent(const Point& pos, uint16_t buttonMask)
 {
   vncPointerMove(pos.x + vncGetScreenX(screenIndex),
                  pos.y + vncGetScreenY(screenIndex));

unix/xserver/hw/vnc/XserverDesktop.h

@@ -95,7 +95,7 @@ class XserverDesktop : public rfb::SDesktop, public rfb::FullFramePixelBuffer,
   void terminate() override;
   void queryConnection(network::Socket* sock,
                        const char* userName) override;
-  void pointerEvent(const rfb::Point& pos, uint8_t buttonMask) override;
+  void pointerEvent(const rfb::Point& pos, uint16_t buttonMask) override;
   void keyEvent(uint32_t keysym, uint32_t keycode, bool down) override;
   unsigned int setScreenLayout(int fb_width, int fb_height,
                                const rfb::ScreenSet& layout) override;

unix/xserver/hw/vnc/vncInput.c

@@ -50,7 +50,7 @@ extern const unsigned int code_map_qnum_to_xorgevdev_len;
 extern const unsigned short code_map_qnum_to_xorgkbd[];
 extern const unsigned int code_map_qnum_to_xorgkbd_len;
 
-#define BUTTONS 7
+#define BUTTONS 9
 
 DeviceIntPtr vncKeyboardDev;
 DeviceIntPtr vncPointerDev;
@@ -207,6 +207,25 @@ static int vncPointerProc(DeviceIntPtr pDevice, int onoff)
 		btn_labels[5] = XIGetKnownProperty(BTN_LABEL_PROP_BTN_HWHEEL_LEFT);
 		btn_labels[6] = XIGetKnownProperty(BTN_LABEL_PROP_BTN_HWHEEL_RIGHT);
 
+    /*
+     * The labels BTN_LABEL_PROP_BTN_SIDE and BTN_LABEL_PROP_BTN_EXTRA
+     * represent the side buttons on mice that are typically used to
+     * navigate back/forward respectively in web browsers (and other
+     * applications).
+     *
+     * There are also two similar labels:
+     *		BTN_LABEL_PROP_BTN_BACK and BTN_LABEL_PROP_BTN_FORWARD,
+     * which are also used by *some* X applications to indicate
+     * back/forward navigation. The SIDE/EXTRA labels seem to be more
+     * widely spread by X applications, and some applications even
+     * detect both labels.
+     *
+     * Most modern mice seem to label the side buttons
+     * (back / forward) with SIDE/EXTRA.
+     */
+		btn_labels[7] = XIGetKnownProperty(BTN_LABEL_PROP_BTN_SIDE);
+		btn_labels[8] = XIGetKnownProperty(BTN_LABEL_PROP_BTN_EXTRA);
+
 		axes_labels[0] = XIGetKnownProperty(AXIS_LABEL_PROP_REL_X);
 		axes_labels[1] = XIGetKnownProperty(AXIS_LABEL_PROP_REL_Y);