fix(frontends): preserve preedit lifecycle

ibus.c

@@ -55,10 +55,12 @@ static int icctr;
 static int busctr;
 static Channel *replyc;
 static const char ibusowner[] = ":1.0";
+static Ictx *preowner;
 
 static DBusHandlerResult onmsg(DBusConnection*, DBusMessage*, void*);
 static DBusHandlerResult handleerror(DBusConnection*, DBusMessage*,
 	const char*, const char*);
+static void checkpreowner(void);
 
 static void
 unlinkaddr(void)
@@ -355,6 +357,8 @@ static void
 dropcontext(Ictx *ctx)
 {
 	releasecontext(ctx);
+	if(preowner == ctx)
+		preowner = nil;
 	memset(ctx, 0, sizeof *ctx);
 }
 
@@ -382,6 +386,8 @@ 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);
+	if(preowner != nil && preowner != ctx)
+		checkpreowner();
 	return 1;
 }
 
@@ -488,10 +494,29 @@ emitpreedit(Ictx *ctx, const char *text)
 		dbus_message_iter_append_basic(&it, DBUS_TYPE_UINT32, &mode);
 	}
 	dbus_message_set_sender(sig, ibusowner);
-	dbus_connection_send(ctx->conn, sig, nil);
+	if(dbus_connection_send(ctx->conn, sig, nil)){
+		if(text[0] != '\0')
+			preowner = ctx;
+		else if(preowner == ctx)
+			preowner = nil;
+	}
 	dbus_message_unref(sig);
 }
 
+static void
+checkpreowner(void)
+{
+	Ictx *ctx;
+	Keyres res;
+
+	ctx = preowner;
+	if(ctx == nil)
+		return;
+	sendrequest(ctx, Keycap, 0, 0, &res);
+	if(!res.eaten)
+		emitpreedit(ctx, "");
+}
+
 static DBusHandlerResult
 handlehello(DBusConnection *c, DBusMessage *m)
 {
@@ -1183,5 +1208,6 @@ ibusthread(void *_)
 			while(dbus_connection_dispatch(conns[i]) == DBUS_DISPATCH_DATA_REMAINS)
 				;
 		pruneconns();
+		checkpreowner();
 	}
 }