Rename the functions as they're exported as C APIs.

`SWIFT_RUNTIME_STDLIB_INTERNAL` does `extern "C"`, so we can't put these
in a namespace and have to use a C-style prefix instead.

Also slightly rearrange the code in `CommandLine.cpp`.

rdar://103397975

Author: al45tair

include/swift/Runtime/Win32.h

@@ -23,9 +23,6 @@
 
 #include <wchar.h>
 
-namespace swift {
-namespace win32 {
-
 /// Convert a wide string to UTF-8.
 ///
 /// @param str The string to convert.
@@ -35,7 +32,7 @@ namespace win32 {
 ///
 /// If @a str cannot be converted to UTF-8, @c nullptr is returned.
 SWIFT_RUNTIME_STDLIB_INTERNAL
-char *copyUTF8FromWide(const wchar_t *str);
+char *_swift_win32_copyUTF8FromWide(const wchar_t *str);
 
 /// Convert a UTF-8 string to a wide string.
 ///
@@ -46,10 +43,8 @@ char *copyUTF8FromWide(const wchar_t *str);
 ///
 /// If @a str cannot be converted to UTF-16, @c nullptr is returned.
 SWIFT_RUNTIME_STDLIB_INTERNAL
-wchar_t *copyWideFromUTF8(const char *str);
+wchar_t *_swift_win32_copyWideFromUTF8(const char *str);
 
-}
-}
 #endif // defined(_WIN32)
 
 #endif // SWIFT_RUNTIME_WIN32_H

stdlib/public/CommandLineSupport/CommandLine.cpp

@@ -203,8 +203,10 @@ static void swift::enumerateUnsafeArgv(const F& body) {
   int argc = 0;
   if (LPWSTR *wargv = CommandLineToArgvW(GetCommandLineW(), &argc)) {
     std::for_each(wargv, wargv + argc, [=] (wchar_t *warg) {
-      auto arg = swift::win32::copyUTF8FromWide(warg);
-      if (!arg) {
+      if (char *arg = _swift_win32_copyUTF8FromWide(warg)) {
+        body(argc, arg);
+        free(arg);
+      } else {
         // Note that GetLastError() and errno may not be so useful here,
         // as in the error case we may have called free(), which might reset
         // either or both of them.
@@ -213,8 +215,6 @@ static void swift::enumerateUnsafeArgv(const F& body) {
                           "UTF-8: %lx, %d.\n",
                           warg, ::GetLastError(), errno);
       }
-      body(argc, arg);
-      free(arg);
     });
 
     LocalFree(wargv);

stdlib/public/runtime/Win32.cpp

@@ -22,7 +22,7 @@
 #include <windows.h>
 
 char *
-swift::win32::copyUTF8FromWide(const wchar_t *str) {
+_swift_win32_copyUTF8FromWide(const wchar_t *str) {
   char *result = nullptr;
   int len = ::WideCharToMultiByte(CP_UTF8, WC_ERR_INVALID_CHARS,
                                   str, -1,
@@ -48,7 +48,7 @@ swift::win32::copyUTF8FromWide(const wchar_t *str) {
 }
 
 wchar_t *
-swift::win32::copyWideFromUTF8(const char *str) {
+_swift_win32_copyWideFromUTF8(const char *str) {
   wchar_t *result = nullptr;
   int len = ::MultiByteToWideChar(CP_UTF8, MB_ERR_INVALID_CHARS,
                                   str, -1,