commit ac73038232dd7d6e41006357de2120f580b9f05f
author Pierre Ossman <ossman@cendio.se> Wed Aug 16 15:20:20 2017 +0200
committer Pierre Ossman <ossman@cendio.se> Mon Aug 21 12:04:33 2017 +0200
tree 970e51423ff671c40abe097b49f115a2a0ec9442
parent d698a6c9536dfa17d8ada12d0dea5c4b53ae08e8

Respect modifiers in x0vncserver

Using XKeysymToKeycode() often gives the incorrect keycode as it
doesn't respect the current modifier state. Use XKB to find the
proper key instead.

This however also means that we need to track the mapping for all
pressed keys to make sure we know the correct keycode when it is
time to release the key.

unix/x0vncserver/x0vncserver.cxx

diff --git a/unix/x0vncserver/x0vncserver.cxx b/unix/x0vncserver/x0vncserver.cxx
index 8f73ac2..34713ea 100644
--- a/unix/x0vncserver/x0vncserver.cxx
+++ b/unix/x0vncserver/x0vncserver.cxx
@@ -39,6 +39,7 @@
 #include <X11/X.h>
 #include <X11/Xlib.h>
 #include <X11/Xutil.h>
+#include <X11/XKBlib.h>
 #ifdef HAVE_XTEST
 #include <X11/extensions/XTest.h>
 #endif
@@ -253,12 +254,61 @@
 #endif
   }
 
+#ifdef HAVE_XTEST
+  KeyCode XkbKeysymToKeycode(Display* dpy, KeySym keysym) {
+    XkbDescPtr xkb;
+    XkbStateRec state;
+    unsigned keycode;
+
+    xkb = XkbGetMap(dpy, XkbAllComponentsMask, XkbUseCoreKbd);
+    if (!xkb)
+      return 0;
+
+    XkbGetState(dpy, XkbUseCoreKbd, &state);
+
+    for (keycode = xkb->min_key_code;
+         keycode <= xkb->max_key_code;
+         keycode++) {
+      KeySym cursym;
+      unsigned int mods;
+      XkbTranslateKeyCode(xkb, keycode, state.compat_state, &mods, &cursym);
+      if (cursym == keysym)
+        break;
+    }
+
+    if (keycode > xkb->max_key_code)
+      keycode = 0;
+
+    XkbFreeKeyboard(xkb, XkbAllComponentsMask, True);
+
+    return keycode;
+  }
+#endif
+
   virtual void keyEvent(rdr::U32 key, bool down) {
 #ifdef HAVE_XTEST
-    if (!haveXtest) return;
-    int keycode = XKeysymToKeycode(dpy, key);
-    if (keycode)
-      XTestFakeKeyEvent(dpy, keycode, down, CurrentTime);
+    int keycode;
+
+    if (!haveXtest)
+      return;
+
+    if (down) {
+      if (pressedKeys.find(key) != pressedKeys.end())
+        keycode = pressedKeys[key];
+      else {
+        // XKeysymToKeycode() doesn't respect state, so we have to use
+        // something slightly more complex
+        keycode = XkbKeysymToKeycode(dpy, key);
+        if (!keycode)
+          return;
+        pressedKeys[key] = keycode;
+      }
+    } else {
+        keycode = pressedKeys[key];
+        pressedKeys.erase(key);
+    }
+
+    XTestFakeKeyEvent(dpy, keycode, down, CurrentTime);
 #endif
   }
 
@@ -301,6 +351,7 @@
   bool haveXtest;
   bool haveDamage;
   int maxButtons;
+  std::map<KeySym, KeyCode> pressedKeys;
   bool running;
 #ifdef HAVE_XDAMAGE
   Damage damage;