[win32] Fix handling of CD-ROM drives.

RomDataFactory::T_create(): Check if the filename is a drive letter.

IRpFile: Move IsDriveLetter*() and related from RpFile_win32.cpp to
IRpFile.hpp, #ifdef'd for Windows only.

CD-ROM drive volume roots can now be handled by rom-properties again.

This broke when support for Wii U Packages was added, since devices are
also considered root directories, so the directory check was done instead
of the device check.

Affects: v2.4 - v2.4.1

NEWS.md

@@ -32,7 +32,7 @@
     * Also fix a bad bounds check that broke the Exports table on these DLLs.
       * Pull request: #438
         * Submitted by @DankRank.
-  * Windows: Properly rescale  the icon and banner sizes.
+  * Windows: Properly rescale the icon and banner sizes.
     * PSP Minis would show a giant banner that messes up the tab display.
     * Fixes #433: [Bug Report] The ROM type is not displayed correctly for some PSP Mini ROMs
       * Reported by @xxmichibxx.
@@ -52,6 +52,11 @@
   * Xbox360_STFS: Fix reading XEXes that overlap a hash block boundary.
     * NOTE: The entire XEX is now read into memory, which may cause slowdown.
       This will be improved later.
+  * Windows: Fix handling of CD-ROM drives.
+    * This broke when support for Wii U Packages was added, since devices are
+      also considered root directories, so the directory check was done instead
+      of the device check.
+    * Affects: v2.4 - v2.4.1
 
 * Other changes:
   * CMake: Added an ENABLE_NETWORKING option to control whether or not

src/libromdata/RomDataFactory.cpp

@@ -991,12 +991,29 @@ RomDataPtr create(const IRpFilePtr &file, unsigned int attrs)
 template<typename CharType>
 static RomDataPtr T_create(const CharType *filename, unsigned int attrs)
 {
+#ifdef _WIN32
+	// If this is a drive letter, try handling it as a file first.
+	if (T_IsDriveLetter(filename[0]) && filename[1] == L':' &&
+		(filename[2] == '\0' || (filename[2] == '\\' && filename[3] == '\0')))
+	{
+		// It's a drive letter. (volume root)
+		const CharType drvfilename[4] = {filename[0], ':', '\\', '\0'};
+		IRpFilePtr file = std::make_shared<RpFile>(filename, RpFile::FM_OPEN_READ_GZ);
+		if (file->isOpen()) {
+			RomDataPtr romData = create(file, attrs);
+			if (romData) {
+				return romData;
+			}
+		}
+	}
+#endif /* _WIN32 */
+
 	// Check if this is a file or a directory.
 	// If it's a file, we'll create an RpFile and then
 	// call create(IRpFile*,unsigned int).
 	if (likely(!FileSystem::is_directory(filename))) {
 		// Not a directory.
-		shared_ptr<RpFile> file = std::make_shared<RpFile>(filename, RpFile::FM_OPEN_READ_GZ);
+		IRpFilePtr file = std::make_shared<RpFile>(filename, RpFile::FM_OPEN_READ_GZ);
 		if (file->isOpen()) {
 			return create(file, attrs);
 		}

src/librpfile/IRpFile.hpp

@@ -27,6 +27,23 @@
 
 namespace LibRpFile {
 
+#ifdef _WIN32
+template<typename CharType>
+static inline constexpr bool T_IsDriveLetter(CharType letter)
+{
+	return (letter >= (CharType)'A') && (letter <= (CharType)'Z');
+}
+
+static inline constexpr bool IsDriveLetterA(char letter)
+{
+	return T_IsDriveLetter(letter);
+}
+static inline constexpr bool IsDriveLetterW(wchar_t letter)
+{
+	return T_IsDriveLetter(letter);
+}
+#endif /* _WIN32 */
+
 class RP_LIBROMDATA_PUBLIC NOVTABLE IRpFile
 {
 protected:

src/librpfile/win32/RpFile_win32.cpp

@@ -2,7 +2,7 @@
  * ROM Properties Page shell extension. (librpfile)                        *
  * RpFile_win32.cpp: Standard file object. (Win32 implementation)          *
  *                                                                         *
- * Copyright (c) 2016-2024 by David Korth.                                 *
+ * Copyright (c) 2016-2025 by David Korth.                                 *
  * SPDX-License-Identifier: GPL-2.0-or-later                               *
  ***************************************************************************/
 
@@ -33,20 +33,6 @@ using std::wstring;
 #include "libwin32common/DelayLoadHelper.h"
 #endif /* _MSC_VER */
 
-static inline constexpr bool IsDriveLetterA(char letter)
-{
-	return (letter >= 'A') && (letter <= 'Z');
-}
-static inline constexpr bool IsDriveLetterW(wchar_t letter)
-{
-	return (letter >= L'A') && (letter <= L'Z');
-}
-#ifdef _UNICODE
-#  define IsDriveLetter(x) IsDriveLetterW(x)
-#else /* !_UNICODE */
-#  define IsDriveLetter(x) IsDriveLetterA(x)
-#endif /* _UNICODE */
-
 namespace LibRpFile {
 
 #ifdef _MSC_VER