Merge pull request #15424 from unknownbrackets/path-unc

Windows: Create SYSTEM directory early

Common/File/Path.cpp

@@ -307,6 +307,17 @@ Path Path::GetRootVolume() const {
 		std::string path = path_.substr(0, 2);
 		return Path(path);
 	}
+	// Support UNC and device paths.
+	if (path_[0] == '/' && path_[1] == '/') {
+		size_t next = 2;
+		if ((path_[2] == '.' || path_[2] == '?') && path_[3] == '/') {
+			// Device path, or "\\.\UNC" path, skip the dot and consider the device the root.
+			next = 4;
+		}
+
+		size_t len = path_.find_first_of('/', next);
+		return Path(path_.substr(0, len));
+	}
 #endif
 	return Path("/");
 }

Core/System.cpp

@@ -731,6 +731,7 @@ void InitSysDirectories() {
 	File::CreateDir(GetSysDirectory(DIRECTORY_GAME));
 	File::CreateDir(GetSysDirectory(DIRECTORY_SAVEDATA));
 	File::CreateDir(GetSysDirectory(DIRECTORY_SAVESTATE));
+	File::CreateDir(GetSysDirectory(DIRECTORY_SYSTEM));
 
 	if (g_Config.currentDirectory.empty()) {
 		g_Config.currentDirectory = GetSysDirectory(DIRECTORY_GAME);

unittest/UnitTest.cpp

@@ -608,6 +608,10 @@ static bool TestPath() {
 	EXPECT_EQ_STR(Path("C:\\Yo").GetFilename(), std::string("Yo"));
 	EXPECT_EQ_STR(Path("C:\\Yo\\Lo").GetDirectory(), std::string("C:/Yo"));
 	EXPECT_EQ_STR(Path("C:\\Yo\\Lo").GetFilename(), std::string("Lo"));
+
+	EXPECT_EQ_STR(Path(R"(\\host\share\filename)").GetRootVolume().ToString(), std::string("//host"));
+	EXPECT_EQ_STR(Path(R"(\\?\UNC\share\filename)").GetRootVolume().ToString(), std::string("//?/UNC"));
+	EXPECT_EQ_STR(Path(R"(\\?\C:\share\filename)").GetRootVolume().ToString(), std::string("//?/C:"));
 #endif
 
 	std::string computedPath;