fs/Traits: enable _UNICODE on Windows

Use wchar_t for everything on Windows.  Solves a lot of filesystem
charset problems.

configure.ac

@@ -103,6 +103,7 @@ mingw32* | windows*)
 	AM_CPPFLAGS="$AM_CPPFLAGS -DWIN32_LEAN_AND_MEAN"
 	AM_CPPFLAGS="$AM_CPPFLAGS -DWINVER=0x0600 -D_WIN32_WINNT=0x0600"
 	AM_CPPFLAGS="$AM_CPPFLAGS -DSTRICT"
+	AM_CPPFLAGS="$AM_CPPFLAGS -DUNICODE -D_UNICODE"
 	LIBS="$LIBS -lws2_32"
 	host_is_windows=yes
 	host_is_unix=no

src/CommandLine.cxx

@@ -35,6 +35,7 @@
 #include "fs/Traits.hxx"
 #include "fs/FileSystem.hxx"
 #include "fs/StandardDirectory.hxx"
+#include "util/Macros.hxx"
 #include "util/Error.hxx"
 #include "util/Domain.hxx"
 #include "util/OptionDef.hxx"
@@ -337,7 +338,19 @@ parse_cmdline(int argc, char **argv, struct options *options,
 
 	if (config_file != nullptr) {
 		/* use specified configuration file */
+#ifdef _UNICODE
+		wchar_t buffer[MAX_PATH];
+		auto result = MultiByteToWideChar(CP_ACP, 0, config_file, -1,
+						  buffer, ARRAY_SIZE(buffer));
+		if (result <= 0) {
+			error.SetLastError("MultiByteToWideChar() failed");
+			return false;
+		}
+
+		return ReadConfigFile(Path::FromFS(buffer), error);
+#else
 		return ReadConfigFile(Path::FromFS(config_file), error);
+#endif
 	}
 
 	/* use default configuration file path */

src/PlaylistFile.cxx

@@ -268,7 +268,17 @@ LoadPlaylistFile(const char *utf8path, Error &error)
 		if (*s == 0 || *s == PLAYLIST_COMMENT)
 			continue;
 
+#ifdef _UNICODE
+		wchar_t buffer[MAX_PATH];
+		auto result = MultiByteToWideChar(CP_ACP, 0, s, -1,
+						  buffer, ARRAY_SIZE(buffer));
+		if (result <= 0)
+			continue;
+
+		const Path path = Path::FromFS(buffer);
+#else
 		const Path path = Path::FromFS(s);
+#endif
 
 		std::string uri_utf8;
 

src/fs/AllocatedPath.cxx

@@ -30,7 +30,7 @@ AllocatedPath::~AllocatedPath() {}
 AllocatedPath
 AllocatedPath::FromUTF8(const char *path_utf8)
 {
-#ifdef HAVE_FS_CHARSET
+#if defined(HAVE_FS_CHARSET) || defined(WIN32)
 	return AllocatedPath(::PathFromUTF8(path_utf8));
 #else
 	return FromFS(path_utf8);

src/fs/Charset.cxx

@@ -25,6 +25,10 @@
 #include "lib/icu/Converter.hxx"
 #include "util/Error.hxx"
 
+#ifdef WIN32
+#include <windows.h>
+#endif
+
 #include <algorithm>
 
 #include <assert.h>
@@ -95,6 +99,24 @@ PathToUTF8(PathTraitsFS::const_pointer path_fs)
 	assert(path_fs != nullptr);
 #endif
 
+#ifdef WIN32
+	int length = WideCharToMultiByte(CP_UTF8, 0, path_fs, -1, nullptr, 0,
+					 nullptr, nullptr);
+	if (length <= 0)
+		return PathTraitsUTF8::string();
+
+	char *buffer = new char[length];
+	length = WideCharToMultiByte(CP_UTF8, 0, path_fs, -1, buffer, length,
+				     nullptr, nullptr);
+	if (length <= 0) {
+		delete[] buffer;
+		return PathTraitsUTF8::string();
+	}
+
+	PathTraitsUTF8::string result(buffer);
+	delete[] buffer;
+	return FixSeparators(std::move(result));
+#else
 #ifdef HAVE_FS_CHARSET
 	if (fs_converter == nullptr)
 #endif
@@ -103,9 +125,10 @@ PathToUTF8(PathTraitsFS::const_pointer path_fs)
 
 	return FixSeparators(fs_converter->ToUTF8(path_fs));
 #endif
+#endif
 }
 
-#ifdef HAVE_FS_CHARSET
+#if defined(HAVE_FS_CHARSET) || defined(WIN32)
 
 PathTraitsFS::string
 PathFromUTF8(PathTraitsUTF8::const_pointer path_utf8)
@@ -115,10 +138,29 @@ PathFromUTF8(PathTraitsUTF8::const_pointer path_utf8)
 	assert(path_utf8 != nullptr);
 #endif
 
+#ifdef WIN32
+	int length = MultiByteToWideChar(CP_UTF8, 0, path_utf8, -1,
+					 nullptr, 0);
+	if (length <= 0)
+		return PathTraitsFS::string();
+
+	wchar_t *buffer = new wchar_t[length];
+	length = MultiByteToWideChar(CP_UTF8, 0, path_utf8, -1,
+				     buffer, length);
+	if (length <= 0) {
+		delete[] buffer;
+		return PathTraitsFS::string();
+	}
+
+	PathTraitsFS::string result(buffer);
+	delete[] buffer;
+	return std::move(result);
+#else
 	if (fs_converter == nullptr)
 		return path_utf8;
 
 	return fs_converter->FromUTF8(path_utf8);
+#endif
 }
 
 #endif

src/fs/NarrowPath.hxx

@@ -22,6 +22,11 @@
 
 #include "check.h"
 #include "Path.hxx"
+#include "util/Macros.hxx"
+
+#ifdef _UNICODE
+#include <windows.h>
+#endif
 
 /**
  * A path name that uses the regular (narrow) "char".  This is used to
@@ -32,10 +37,25 @@ class NarrowPath {
 	typedef char value_type;
 	typedef const char *const_pointer;
 
+#ifdef _UNICODE
+	char value[PATH_MAX];
+#else
 	const_pointer value;
+#endif
 
 public:
+#ifdef _UNICODE
+	explicit NarrowPath(Path _path) {
+		auto result = WideCharToMultiByte(CP_ACP, 0,
+						  _path.c_str(), -1,
+						  value, ARRAY_SIZE(value),
+						  nullptr, nullptr);
+		if (result < 0)
+			value[0] = 0;
+	}
+#else
 	explicit NarrowPath(Path _path):value(_path.c_str()) {}
+#endif
 
 	operator const_pointer() const {
 		return value;

src/fs/Traits.hxx

@@ -43,7 +43,11 @@
  * This class describes the nature of a native filesystem path.
  */
 struct PathTraitsFS {
+#ifdef WIN32
+	typedef std::wstring string;
+#else
 	typedef std::string string;
+#endif
 	typedef string::traits_type char_traits;
 	typedef char_traits::char_type value_type;
 	typedef value_type *pointer;

src/net/SocketError.cxx

@@ -20,6 +20,7 @@
 #include "config.h"
 #include "SocketError.hxx"
 #include "util/Domain.hxx"
+#include "util/Macros.hxx"
 
 #include <string.h>
 
@@ -29,13 +30,31 @@ const Domain socket_domain("socket");
 
 SocketErrorMessage::SocketErrorMessage(socket_error_t code)
 {
+#ifdef _UNICODE
+	wchar_t buffer[ARRAY_SIZE(msg)];
+#else
+	auto *buffer = msg;
+#endif
+
 	DWORD nbytes = FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM |
 				     FORMAT_MESSAGE_IGNORE_INSERTS |
 				     FORMAT_MESSAGE_MAX_WIDTH_MASK,
-				     NULL, code, 0,
-				     (LPSTR)msg, sizeof(msg), NULL);
-	if (nbytes == 0)
+				     nullptr, code, 0,
+				     buffer, ARRAY_SIZE(msg), nullptr);
+	if (nbytes == 0) {
 		strcpy(msg, "Unknown error");
+		return;
+	}
+
+#ifdef _UNICODE
+	auto length = WideCharToMultiByte(CP_UTF8, 0, buffer, -1,
+					  msg, ARRAY_SIZE(msg),
+					  nullptr, nullptr);
+	if (length <= 0) {
+		strcpy(msg, "WideCharToMultiByte() error");
+		return;
+	}
+#endif
 }
 
 #else