file_util: Implement `RecursivelyCreateDir`

With this, we no longer require `std::filesystem` support to create the
save file directory when it does not exist.

Note that by default the save file directory exists because it is
created by SDL, so this is mostly useful on platforms that override the
save directory or use `UNPACKED_SAVES`.

Packaging/windows/CMakePresets.json

@@ -74,15 +74,18 @@
 	"testPresets": [
 		{
 			"name": "ninja-vcpkg-debug",
-			"configurePreset": "ninja-vcpkg-debug"
+			"configurePreset": "ninja-vcpkg-debug",
+			"output": {"outputOnFailure": true}
 		},
 		{
 			"name": "ninja-vcpkg-relwithdebinfo",
-			"configurePreset": "ninja-vcpkg-relwithdebinfo"
+			"configurePreset": "ninja-vcpkg-relwithdebinfo",
+			"output": {"outputOnFailure": true}
 		},
 		{
 			"name": "ninja-vcpkg-discord-relwithdebinfo",
-			"configurePreset": "ninja-vcpkg-discord-relwithdebinfo"
+			"configurePreset": "ninja-vcpkg-discord-relwithdebinfo",
+			"output": {"outputOnFailure": true}
 		}
 	]
 }

Source/mpq/mpq_writer.cpp

@@ -88,15 +88,8 @@ bool IsUnallocatedBlock(const MpqBlockEntry *block)
 
 MpqWriter::MpqWriter(const char *path)
 {
-#ifdef DVL_HAS_FILESYSTEM
-	{
-		std::error_code error;
-		std::filesystem::create_directories(std::filesystem::path(path).parent_path(), error);
-		if (error) {
-			LogError("failed to create directory: {}", error.message());
-		}
-	}
-#endif
+	const std::string dir = std::string(Dirname(path));
+	RecursivelyCreateDir(dir.c_str());
 	LogVerbose("Opening {}", path);
 	std::string error;
 	bool exists = FileExists(path);

Source/options.cpp

@@ -236,15 +236,7 @@ void SaveIni()
 {
 	if (!IniChanged)
 		return;
-#ifdef DVL_HAS_FILESYSTEM
-	{
-		std::error_code error;
-		std::filesystem::create_directories(paths::ConfigPath(), error);
-		if (error) {
-			LogError("failed to create directory: {}", error.message());
-		}
-	}
-#endif
+	RecursivelyCreateDir(paths::ConfigPath().c_str());
 	const std::string iniPath = GetIniPath();
 	FILE *file = OpenFile(iniPath.c_str(), "wb");
 	if (file != nullptr) {

Source/utils/file_util.cpp

@@ -5,6 +5,7 @@
 
 #include <algorithm>
 #include <string>
+#include <vector>
 
 #include <SDL.h>
 
@@ -38,6 +39,13 @@
 #include <copyfile.h>
 #endif
 
+// We include sys/stat.h for mkdir where available.
+#if !defined(DVL_HAS_FILESYSTEM) && defined(__has_include) && !defined(_WIN32)
+#if __has_include(<sys/stat.h>)
+#include <sys/stat.h>
+#endif
+#endif
+
 namespace devilution {
 
 #if (defined(_WIN64) || defined(_WIN32)) && !defined(NXDK)
@@ -55,6 +63,18 @@ std::unique_ptr<wchar_t[]> ToWideChar(string_view path)
 }
 #endif
 
+string_view Dirname(string_view path)
+{
+	while (path.size() > 1 && path.back() == DirectorySeparator)
+		path.remove_suffix(1);
+	if (path.size() == 1 && path.back() == DirectorySeparator)
+		return DIRECTORY_SEPARATOR_STR;
+	const size_t sep = path.find_last_of(DIRECTORY_SEPARATOR_STR);
+	if (sep == string_view::npos)
+		return ".";
+	return string_view { path.data(), sep };
+}
+
 bool FileExists(const char *path)
 {
 #if defined(_WIN64) || defined(_WIN32)
@@ -95,9 +115,10 @@ bool FileExists(const char *path)
 #endif
 }
 
-bool FileExistsAndIsWriteable(const char *path)
-{
 #if defined(_WIN64) || defined(_WIN32)
+namespace {
+DWORD WindowsGetFileAttributes(const char *path)
+{
 #if defined(NXDK)
 	const DWORD attr = ::GetFileAttributesA(path);
 #else
@@ -108,8 +129,7 @@ bool FileExistsAndIsWriteable(const char *path)
 	}
 	const DWORD attr = ::GetFileAttributesW(&pathUtf16[0]);
 #endif
-	const bool exists = attr != INVALID_FILE_ATTRIBUTES;
-	if (!exists) {
+	if (attr == INVALID_FILE_ATTRIBUTES) {
 		if (::GetLastError() == ERROR_FILE_NOT_FOUND || ::GetLastError() == ERROR_PATH_NOT_FOUND) {
 			::SetLastError(ERROR_SUCCESS);
 		} else {
@@ -120,7 +140,31 @@ bool FileExistsAndIsWriteable(const char *path)
 #endif
 		}
 	}
-	return exists && (attr & FILE_ATTRIBUTE_READONLY) == 0;
+	return attr;
+}
+} // namespace
+
+#endif
+
+bool DirectoryExists(const char *path)
+{
+#if defined(_WIN64) || defined(_WIN32)
+	const DWORD attr = WindowsGetFileAttributes(path);
+	return attr != INVALID_FILE_ATTRIBUTES && (attr & FILE_ATTRIBUTE_DIRECTORY) != 0;
+#elif defined(DVL_HAS_FILESYSTEM)
+	std::error_code error;
+	return std::filesystem::is_directory(path, error);
+#elif (_POSIX_C_SOURCE >= 200112L || defined(_BSD_SOURCE) || defined(__APPLE__)) && !defined(__ANDROID__)
+	struct ::stat statResult;
+	return ::stat(path, &statResult) == 0 && S_ISDIR(statResult.st_mode);
+#endif
+}
+
+bool FileExistsAndIsWriteable(const char *path)
+{
+#if defined(_WIN64) || defined(_WIN32)
+	const DWORD attr = WindowsGetFileAttributes(path);
+	return attr != INVALID_FILE_ATTRIBUTES && (attr & FILE_ATTRIBUTE_READONLY) == 0;
 #elif (_POSIX_C_SOURCE >= 200112L || defined(_BSD_SOURCE) || defined(__APPLE__)) && !defined(__ANDROID__)
 	return ::access(path, W_OK) == 0;
 #else
@@ -164,6 +208,74 @@ bool GetFileSize(const char *path, std::uintmax_t *size)
 #endif
 }
 
+bool CreateDir(const char *path)
+{
+#ifdef DVL_HAS_FILESYSTEM
+	std::error_code error;
+	std::filesystem::create_directory(path, error);
+	if (error) {
+		LogError("failed to create directory {}: {}", path, error.message());
+		return false;
+	}
+	return true;
+#elif defined(_WIN64) || defined(_WIN32)
+#ifdef NXDK
+	if (::CreateDirectoryA(path, /*lpSecurityAttributes=*/nullptr) != 0)
+		return true;
+	if (::GetLastError() == ERROR_ALREADY_EXISTS)
+		return true;
+	LogError("failed to create directory {}", path);
+	return false;
+#else
+	const auto pathUtf16 = ToWideChar(path);
+	if (pathUtf16 == nullptr) {
+		LogError("UTF-8 -> UTF-16 conversion error code {}", ::GetLastError());
+		return false;
+	}
+	if (::CreateDirectoryW(&pathUtf16[0], /*lpSecurityAttributes=*/nullptr) != 0)
+		return true;
+	if (::GetLastError() == ERROR_ALREADY_EXISTS)
+		return true;
+	LogError("failed to create directory {}", path);
+	return false;
+#endif
+#else
+	const int result = ::mkdir(path, 0777);
+	if (result != 0 && result != EEXIST) {
+		LogError("failed to create directory {}", path);
+		return false;
+	}
+	return true;
+#endif
+}
+
+void RecursivelyCreateDir(const char *path)
+{
+#ifdef DVL_HAS_FILESYSTEM
+	std::error_code error;
+	std::filesystem::create_directories(path, error);
+	if (error) {
+		LogError("failed to create directory {}: {}", path, error.message());
+	}
+#else
+	if (DirectoryExists(path))
+		return;
+	std::vector<std::string> paths;
+	std::string cur { path };
+	do {
+		paths.push_back(cur);
+		string_view parent = Dirname(cur);
+		if (parent == cur)
+			break;
+		cur.assign(parent.data(), parent.size());
+	} while (!DirectoryExists(cur.c_str()));
+	for (auto it = std::rbegin(paths); it != std::rend(paths); ++it) {
+		if (!CreateDir(it->c_str()))
+			return;
+	}
+#endif
+}
+
 bool ResizeFile(const char *path, std::uintmax_t size)
 {
 #if defined(_WIN64) || defined(_WIN32)

Source/utils/file_util.h

@@ -9,6 +9,14 @@
 
 namespace devilution {
 
+#ifdef _WIN32
+constexpr char DirectorySeparator = '\\';
+#define DIRECTORY_SEPARATOR_STR "\\"
+#else
+constexpr char DirectorySeparator = '/';
+#define DIRECTORY_SEPARATOR_STR "/"
+#endif
+
 bool FileExists(const char *path);
 
 inline bool FileExists(const std::string &str)
@@ -16,8 +24,19 @@ inline bool FileExists(const std::string &str)
 	return FileExists(str.c_str());
 }
 
+bool DirectoryExists(const char *path);
+string_view Dirname(string_view path);
 bool FileExistsAndIsWriteable(const char *path);
 bool GetFileSize(const char *path, std::uintmax_t *size);
+
+/**
+ * @brief Creates a single directory (non-recursively).
+ *
+ * @return True if the directory already existed or has been created sucessfully.
+ */
+bool CreateDir(const char *path);
+
+void RecursivelyCreateDir(const char *path);
 bool ResizeFile(const char *path, std::uintmax_t size);
 void RenameFile(const char *from, const char *to);
 void CopyFileOverwrite(const char *from, const char *to);

Source/utils/paths.h

@@ -6,14 +6,6 @@
 
 namespace devilution {
 
-#ifdef _WIN32
-constexpr char DirectorySeparator = '\\';
-#define DIRECTORY_SEPARATOR_STR "\\"
-#else
-constexpr char DirectorySeparator = '/';
-#define DIRECTORY_SEPARATOR_STR "/"
-#endif
-
 namespace paths {
 
 const std::string &BasePath();

test/file_util_test.cpp

@@ -61,4 +61,25 @@ TEST(FileUtil, ResizeFile)
 	EXPECT_EQ(size, 30);
 }
 
+TEST(FileUtil, Dirname)
+{
+	EXPECT_EQ(Dirname(""), ".");
+	EXPECT_EQ(Dirname("abc"), ".");
+	EXPECT_EQ(Dirname(DIRECTORY_SEPARATOR_STR), DIRECTORY_SEPARATOR_STR);
+	EXPECT_EQ(Dirname(DIRECTORY_SEPARATOR_STR DIRECTORY_SEPARATOR_STR), DIRECTORY_SEPARATOR_STR);
+	EXPECT_EQ(Dirname("a" DIRECTORY_SEPARATOR_STR "b"), "a");
+	EXPECT_EQ(Dirname("a" DIRECTORY_SEPARATOR_STR "b" DIRECTORY_SEPARATOR_STR "c"),
+	    "a" DIRECTORY_SEPARATOR_STR "b");
+	EXPECT_EQ(Dirname("a" DIRECTORY_SEPARATOR_STR "b" DIRECTORY_SEPARATOR_STR "c"),
+	    "a" DIRECTORY_SEPARATOR_STR "b");
+}
+
+TEST(FileUtil, RecursivelyCreateDir)
+{
+	const std::string path = GetTmpPathName(/*suffix=*/"") + DIRECTORY_SEPARATOR_STR
+	    + "a" + DIRECTORY_SEPARATOR_STR + "b" + DIRECTORY_SEPARATOR_STR + "c";
+	RecursivelyCreateDir(path.c_str());
+	EXPECT_TRUE(DirectoryExists(path.c_str()));
+}
+
 } // namespace