ipc: share one keysym and modifier mapping across frontends

The keysym-to-engine-key rule lived in ibus.c, xim/xim.c and gtk/main.c,
and the copies disagreed: GTK sent keypad digits as special keys while
IBus and XIM sent '1'..'9'. Modifiers were rebuilt bit by bit in two
places although Mmask already is the X core layout; only the virtual
Super bit (26) that GDK and IBus set needs folding. ipckey/ipcmod in
ipc.c serve the daemon, the module and the tests.

gtk/main.c

@@ -223,36 +223,6 @@ srvconnect(Im *im)
 	return 0;
 }
 
-static uint32_t
-kget(uint32_t gdk)
-{
-	uint32_t u;
-
-	u = gdk_keyval_to_unicode(gdk);
-	if((gdk & 0xff000000) == 0x01000000 && u != 0)
-		return u;
-	if(gdk >= 0xff00 && gdk <= 0xffff)
-		return Kspec + (gdk - 0xff00);
-	return u;
-}
-
-static uint32_t
-mget(uint32_t state)
-{
-	uint32_t m;
-
-	m = 0;
-	if(state & GDK_SHIFT_MASK)
-		m |= Mshift;
-	if(state & GDK_CONTROL_MASK)
-		m |= Mctrl;
-	if(state & GDK_MOD1_MASK)
-		m |= Malt;
-	if(state & GDK_SUPER_MASK)
-		m |= Msuper;
-	return m;
-}
-
 static void
 simplecommit(GtkIMContext *ctx, const char *s, Im *im)
 {
@@ -327,8 +297,8 @@ kpress(GtkIMContext *ctx, GdkEventKey *ev)
 	}
 	if(im->simpleactive)
 		return simplefilter(ctx, ev, 0);
-	key = kget(ev->keyval);
+	key = ipckey(ev->keyval, gdk_keyval_to_unicode(ev->keyval));
-	mod = mget(ev->state);
+	mod = ipcmod(ev->state);
 	if(im->private || key == 0)
 		return simplefilter(ctx, ev, 0);
 	if(srvconnect(im) < 0)

ibus.c

@@ -17,7 +17,6 @@ enum
 	Maxwatches	= 2*Maxconns + 1,
 	Maxcontexts	= Maxclients,
 	Relmask		= 1<<30,
-	Ibussupermask	= 1<<26,
 	/* IBus wire constants; the daemon does not link libibus. */
 	Ibuscappreedit	= 1<<0,
 	Ibuspurposepassword = 8,
@@ -266,32 +265,6 @@ togglewatch(DBusWatch *w, void *_)
 	USED(_);
 }
 
-static u32int
-kget(u32int sym)
-{
-	u32int c;
-
-	c = xkb_keysym_to_utf32(sym);
-	if(c >= ' ' && c != 0x7f)
-		return c;
-	if(sym >= 0xff00 && sym <= 0xffff)
-		return Kspec + (sym - 0xff00);
-	return c;
-}
-
-static u32int
-mget(u32int state)
-{
-	u32int m;
-
-	m = 0;
-	if(state & (1<<0)) m |= Mshift;
-	if(state & (1<<2)) m |= Mctrl;
-	if(state & (1<<3)) m |= Malt;
-	if(state & ((1<<6)|Ibussupermask)) m |= Msuper;
-	return m;
-}
-
 static Ictx*
 findcontext(DBusConnection *conn, const char *path)
 {
@@ -385,7 +358,8 @@ processkey(Ictx *ctx, u32int sym, u32int state, Keyres *res)
 {
 	if(state & Relmask || !ctx->focused || hidden(ctx))
 		return 0;
-	sendrequest(ctx, Keypress, kget(sym), mget(state), res);
+	sendrequest(ctx, Keypress, ipckey(sym, xkb_keysym_to_utf32(sym)),
+		ipcmod(state), res);
 	if(preowner != nil && preowner != ctx)
 		checkpreowner();
 	return 1;

ipc.c

@@ -223,6 +223,31 @@ Bad:
 	return -1;
 }
 
+/*
+ * Engine key for an X keysym and its Unicode value: printable characters
+ * as themselves, the function keysyms 0xff00-0xffff as Kspec+offset.
+ */
+uint32_t
+ipckey(uint32_t sym, uint32_t unicode)
+{
+	if(unicode >= ' ' && unicode != 0x7f)
+		return unicode;
+	if(sym >= 0xff00 && sym <= 0xffff)
+		return Kspec + (sym - 0xff00);
+	return unicode;
+}
+
+uint32_t
+ipcmod(uint32_t state)
+{
+	uint32_t m;
+
+	m = state & Mmask;
+	if(state & Msupervirt)
+		m |= Msuper;
+	return m;
+}
+
 void
 ipcpackreq(unsigned char req[Ipcreqsz], int want, uint32_t mod,
 	uint32_t key)

ipc.h

@@ -38,11 +38,13 @@ enum
 	Kmodfirst = Kspec|0xe1,
 	Kmodlast = Kspec|0xee,
 
+	/* X core modifier bits; GDK and IBus also flag Super at bit 26. */
 	Mshift = 1<<0,
 	Mctrl = 1<<2,
 	Malt = 1<<3,
 	Msuper = 1<<6,
 	Mmask = Mshift|Mctrl|Malt|Msuper,
+	Msupervirt = 1<<26,
 
 	Ipcreqsz = 6,
 	Ipccaretsz = 16,
@@ -70,6 +72,8 @@ struct Ipcresp
 	size_t	preeditlen;
 };
 
+uint32_t	ipckey(uint32_t, uint32_t);
+uint32_t	ipcmod(uint32_t);
 void	ipcpackreq(unsigned char[Ipcreqsz], int, uint32_t, uint32_t);
 void	ipcpackreset(unsigned char[Ipcreqsz], int);
 void	ipcpackcap(unsigned char[Ipcreqsz], int);

tests/ipc_test.c

@@ -46,6 +46,18 @@ ipc_masks_modifiers(struct ct *t)
 	CT_EQ_UINT(t, 0, mod);
 	CT_EQ_UINT(t, 0, key);
 	CT_CHECK(t, ipcreqreset(buf));
+
+	/* Frontends share one keysym and modifier mapping. */
+	CT_EQ_UINT(t, 'a', ipckey('a', 'a'));
+	CT_EQ_UINT(t, '1', ipckey(0xffb1, '1'));	/* KP_1 */
+	CT_EQ_UINT(t, Kret, ipckey(0xff0d, '\r'));
+	CT_EQ_UINT(t, Kback, ipckey(0xff08, 8));
+	CT_EQ_UINT(t, Kspec + 0xff, ipckey(0xffff, 0x7f));	/* Delete */
+	CT_EQ_UINT(t, 0x1f642, ipckey(0x101f642, 0x1f642));
+	CT_EQ_UINT(t, 0, ipckey(0xfe03, 0));	/* ISO_Level3_Shift */
+	CT_EQ_UINT(t, Mshift|Mctrl, ipcmod(Mshift|Mctrl|(1<<1)|(1<<4)));
+	CT_EQ_UINT(t, Msuper, ipcmod(1<<6));
+	CT_EQ_UINT(t, Msuper, ipcmod(1<<26));
 }
 
 void

xim/xim.c

@@ -249,12 +249,6 @@ out:
 	return ok;
 }
 
-static u32int
-kget(uint8_t kc, u16int state)
-{
-	return keymaplookup(kstate, kc, state);
-}
-
 static xcb_screen_t*
 getscreen(int scr)
 {
@@ -466,7 +460,7 @@ sendrequest(Ic *state, int op, u32int key, u32int mod, Keyres *res)
 	kr.cap = state->cap;
 	kr.op = op;
 	kr.ks = key;
-	kr.mod = mod & Mmask;
+	kr.mod = ipcmod(mod);
 	kr.caret = state->caret;
 	kr.reply = replyc;
 	chansend(keyc, &kr);
@@ -557,17 +551,11 @@ kpress(Ic *state, xcb_key_press_event_t *ev)
 {
 	Keyres res;
 	char buf[Maxutf];
-	u32int key, rune;
+	u32int key;
 	int n, wasvalid;
 
-	key = kget(ev->detail, ev->state);
+	key = keymaplookup(kstate, ev->detail, ev->state);
-	rune = xkb_keysym_to_utf32(key);
+	key = ipckey(key, xkb_keysym_to_utf32(key));
-	if(rune >= ' ' && rune != 0x7f)
-		key = rune;
-	else if(key >= 0xff00 && key <= 0xffff)
-		key = Kspec + (key - 0xff00);
-	else
-		key = rune;
 	if(meaningful(key)){
 		wasvalid = state->caret.valid;
 		refreshplace(state);