[common] windows: add native path and UTF support

client/tests/CMakeLists.txt

@@ -14,6 +14,19 @@ set_tests_properties(common-platform-tests PROPERTIES
   TIMEOUT 10
 )
 
+if(LG_CLIENT_PLATFORM_WINDOWS)
+  add_executable(common-windows-tests
+    common_windows_test.c
+  )
+  target_link_libraries(common-windows-tests
+    ${EXE_FLAGS}
+    lg_common
+  )
+  add_test(NAME common-windows-tests
+    COMMAND common-windows-tests
+  )
+endif()
+
 add_executable(font-tests
   font_test.c
   ../src/font.c

client/tests/common_windows_test.c

@@ -0,0 +1,50 @@
+/**
+ * Looking Glass
+ * Copyright © 2017-2026 The Looking Glass Authors
+ * https://looking-glass.io
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc., 59
+ * Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include "test.h"
+
+#include "common/win32.h"
+
+#include <stdlib.h>
+#include <string.h>
+#include <wchar.h>
+
+static void testUtfConversion(void)
+{
+  static const char input[] = "Looking Glass \xF0\x9F\x96\xA5";
+
+  wchar_t * wide = lgUtf8ToWide(input);
+  CHECK(wide);
+  CHECK(wcslen(wide) > 0);
+
+  char * output = lgWideToUtf8(wide);
+  CHECK(output);
+  CHECK(strcmp(output, input) == 0);
+  free(output);
+  free(wide);
+
+  CHECK(!lgUtf8ToWide("\xC0\xAF"));
+}
+
+int main(void)
+{
+  testUtfConversion();
+  return 0;
+}