Implement unicode on console, move readline into driver

luprex/cpp/drv/driver-linux.cpp

@@ -2,6 +2,7 @@
 
 #include "drvutil.hpp"
 #include "sslutil.hpp"
+#include "readline.hpp"
 #include "../core/enginewrapper.hpp"
 
 #include <iostream>
@@ -217,12 +218,21 @@ static int socket_poll(struct pollfd *pollvec, int pollcount, int mstimeout, std
     return 0;
 }
 
-static int console_write(const char *bytes, int nbytes) {
-    return write(1, bytes, nbytes);
+// Write unicode onto the console.
+static void console_write(const CodepointString &cps) {
+    std::string utf8 = ReadlineDevice::to_utf8(cps);
+    write(1, utf8.c_str(), utf8.size());
 }
 
-static int console_read(char *bytes, int nbytes) {
-    return read(0, bytes, nbytes);
+static CodepointString console_read() {
+    CodepointString result;
+    char buffer[512];
+    int nread = read(0, buffer, 512);
+    if (nread > 0) {
+        std::string_view s(buffer, nread);
+        result = ReadlineDevice::from_utf8(s, nullptr);
+    }
+    return result;
 }
 
 static void call_init_engine_wrapper(const std::filesystem::path &luprexroot, EngineWrapper *w) {