godot/drivers/windows/file_access_windows.cpp

/**************************************************************************/
/*  file_access_windows.cpp                                               */
/**************************************************************************/
/*                         This file is part of:                          */
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/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur.                  */
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#ifdef WINDOWS_ENABLED

#include "file_access_windows.h"

#include "core/config/project_settings.h"
#include "core/os/os.h"
#include "core/string/print_string.h"

#include <share.h> // _SH_DENYNO
#include <shlwapi.h>
#define WIN32_LEAN_AND_MEAN
#include <windows.h>

#include <errno.h>
#include <io.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <tchar.h>
#include <wchar.h>

#ifdef _MSC_VER
#define S_ISREG(m) ((m) & _S_IFREG)
#endif

void FileAccessWindows::check_errors(bool p_write) const {
	ERR_FAIL_NULL(f);

	last_error = OK;
	if (ferror(f)) {
		if (p_write) {
			last_error = ERR_FILE_CANT_WRITE;
		} else {
			last_error = ERR_FILE_CANT_READ;
		}
	}
	if (!p_write && feof(f)) {
		last_error = ERR_FILE_EOF;
	}
}

bool FileAccessWindows::is_path_invalid(const String &p_path) {
	// Check for invalid operating system file.
	String fname = p_path.get_file().to_lower();

	int dot = fname.find_char('.');
	if (dot != -1) {
		fname = fname.substr(0, dot);
	}
	return invalid_files.has(fname);
}

String FileAccessWindows::fix_path(const String &p_path) const {
	String r_path = FileAccess::fix_path(p_path);

	if (r_path.is_relative_path()) {
		Char16String current_dir_name;
		size_t str_len = GetCurrentDirectoryW(0, nullptr);
		current_dir_name.resize(str_len + 1);
		GetCurrentDirectoryW(current_dir_name.size(), (LPWSTR)current_dir_name.ptrw());
		r_path = String::utf16((const char16_t *)current_dir_name.get_data()).trim_prefix(R"(\\?\)").replace("\\", "/").path_join(r_path);
	}
	r_path = r_path.simplify_path();
	r_path = r_path.replace("/", "\\");
	if (!r_path.is_network_share_path() && !r_path.begins_with(R"(\\?\)")) {
		r_path = R"(\\?\)" + r_path;
	}
	return r_path;
}

Error FileAccessWindows::open_internal(const String &p_path, int p_mode_flags) {
	if (is_path_invalid(p_path)) {
#ifdef DEBUG_ENABLED
		if (p_mode_flags != READ) {
			WARN_PRINT("The path :" + p_path + " is a reserved Windows system pipe, so it can't be used for creating files.");
		}
#endif
		return ERR_INVALID_PARAMETER;
	}

	_close();

	path_src = p_path;
	path = fix_path(p_path);

	const WCHAR *mode_string;

	if (p_mode_flags == READ) {
		mode_string = L"rb";
	} else if (p_mode_flags == WRITE) {
		mode_string = L"wb";
	} else if (p_mode_flags == READ_WRITE) {
		mode_string = L"rb+";
	} else if (p_mode_flags == WRITE_READ) {
		mode_string = L"wb+";
	} else {
		return ERR_INVALID_PARAMETER;
	}

	if (path.ends_with(":\\") || path.ends_with(":")) {
		return ERR_FILE_CANT_OPEN;
	}
	DWORD file_attr = GetFileAttributesW((LPCWSTR)(path.utf16().get_data()));
	if (file_attr != INVALID_FILE_ATTRIBUTES && (file_attr & FILE_ATTRIBUTE_DIRECTORY)) {
		return ERR_FILE_CANT_OPEN;
	}

#ifdef TOOLS_ENABLED
	// Windows is case insensitive in the default configuration, but other platforms can be sensitive to it
	// To ease cross-platform development, we issue a warning if users try to access
	// a file using the wrong case (which *works* on Windows, but won't on other
	// platforms), we only check for relative paths, or paths in res:// or user://,
	// other paths aren't likely to be portable anyway.
	if (p_mode_flags == READ && (p_path.is_relative_path() || get_access_type() != ACCESS_FILESYSTEM)) {
		String base_path = p_path;
		String working_path;
		String proper_path;

		if (get_access_type() == ACCESS_RESOURCES) {
			if (ProjectSettings::get_singleton()) {
				working_path = ProjectSettings::get_singleton()->get_resource_path();
				if (!working_path.is_empty()) {
					base_path = working_path.path_to_file(base_path);
				}
			}
			proper_path = "res://";
		} else if (get_access_type() == ACCESS_USERDATA) {
			working_path = OS::get_singleton()->get_user_data_dir();
			if (!working_path.is_empty()) {
				base_path = working_path.path_to_file(base_path);
			}
			proper_path = "user://";
		}
		working_path = fix_path(working_path);

		WIN32_FIND_DATAW d;
		Vector<String> parts = base_path.simplify_path().split("/");

		bool mismatch = false;

		for (const String &part : parts) {
			working_path = working_path + "\\" + part;

			HANDLE fnd = FindFirstFileW((LPCWSTR)(working_path.utf16().get_data()), &d);
			if (fnd == INVALID_HANDLE_VALUE) {
				mismatch = false;
				break;
			}

			const String fname = String::utf16((const char16_t *)(d.cFileName));

			FindClose(fnd);

			if (!mismatch) {
				mismatch = (part != fname && part.findn(fname) == 0);
			}

			proper_path = proper_path.path_join(fname);
		}

		if (mismatch) {
			WARN_PRINT("Case mismatch opening requested file '" + p_path + "', stored as '" + proper_path + "' in the filesystem. This file will not open when exported to other case-sensitive platforms.");
		}
	}
#endif

	if (is_backup_save_enabled() && p_mode_flags == WRITE) {
		save_path = path;
		// Create a temporary file in the same directory as the target file.
		// Note: do not use GetTempFileNameW, it's not long path aware!
		String tmpfile;
		uint64_t id = OS::get_singleton()->get_ticks_usec();
		while (true) {
			tmpfile = path + itos(id++) + ".tmp";
			HANDLE handle = CreateFileW((LPCWSTR)tmpfile.utf16().get_data(), GENERIC_WRITE, 0, nullptr, CREATE_NEW, FILE_ATTRIBUTE_NORMAL, nullptr);
			if (handle != INVALID_HANDLE_VALUE) {
				CloseHandle(handle);
				break;
			}
			if (GetLastError() != ERROR_FILE_EXISTS && GetLastError() != ERROR_SHARING_VIOLATION) {
				last_error = ERR_FILE_CANT_WRITE;
				return FAILED;
			}
		}
		path = tmpfile;
	}

	f = _wfsopen((LPCWSTR)(path.utf16().get_data()), mode_string, is_backup_save_enabled() ? _SH_SECURE : _SH_DENYNO);

	if (f == nullptr) {
		switch (errno) {
			case ENOENT: {
				last_error = ERR_FILE_NOT_FOUND;
			} break;
			default: {
				last_error = ERR_FILE_CANT_OPEN;
			} break;
		}
		return last_error;
	} else {
		last_error = OK;
		flags = p_mode_flags;
		return OK;
	}
}

void FileAccessWindows::_close() {
	if (!f) {
		return;
	}

	fclose(f);
	f = nullptr;

	if (!save_path.is_empty()) {
		// This workaround of trying multiple times is added to deal with paranoid Windows
		// antiviruses that love reading just written files even if they are not executable, thus
		// locking the file and preventing renaming from happening.

		bool rename_error = true;
		const Char16String &path_utf16 = path.utf16();
		const Char16String &save_path_utf16 = save_path.utf16();
		for (int i = 0; i < 1000; i++) {
			if (ReplaceFileW((LPCWSTR)(save_path_utf16.get_data()), (LPCWSTR)(path_utf16.get_data()), nullptr, REPLACEFILE_IGNORE_MERGE_ERRORS | REPLACEFILE_IGNORE_ACL_ERRORS, nullptr, nullptr)) {
				rename_error = false;
			} else {
				// Either the target exists and is locked (temporarily, hopefully)
				// or it doesn't exist; let's assume the latter before re-trying.
				rename_error = MoveFileW((LPCWSTR)(path_utf16.get_data()), (LPCWSTR)(save_path_utf16.get_data())) == 0;
			}

			if (!rename_error) {
				break;
			}

			OS::get_singleton()->delay_usec(1000);
		}

		if (rename_error) {
			if (close_fail_notify) {
				close_fail_notify(save_path);
			}
		}

		save_path = "";

		ERR_FAIL_COND_MSG(rename_error, "Safe save failed. This may be a permissions problem, but also may happen because you are running a paranoid antivirus. If this is the case, please switch to Windows Defender or disable the 'safe save' option in editor settings. This makes it work, but increases the risk of file corruption in a crash.");
	}
}

String FileAccessWindows::get_path() const {
	return path_src;
}

String FileAccessWindows::get_path_absolute() const {
	return path.trim_prefix(R"(\\?\)").replace("\\", "/");
}

bool FileAccessWindows::is_open() const {
	return (f != nullptr);
}

void FileAccessWindows::seek(uint64_t p_position) {
	ERR_FAIL_NULL(f);

	if (_fseeki64(f, p_position, SEEK_SET)) {
		check_errors();
	}
	prev_op = 0;
}

void FileAccessWindows::seek_end(int64_t p_position) {
	ERR_FAIL_NULL(f);

	if (_fseeki64(f, p_position, SEEK_END)) {
		check_errors();
	}
	prev_op = 0;
}

uint64_t FileAccessWindows::get_position() const {
	int64_t aux_position = _ftelli64(f);
	if (aux_position < 0) {
		check_errors();
	}
	return aux_position;
}

uint64_t FileAccessWindows::get_length() const {
	ERR_FAIL_NULL_V(f, 0);

	uint64_t pos = get_position();
	_fseeki64(f, 0, SEEK_END);
	uint64_t size = get_position();
	_fseeki64(f, pos, SEEK_SET);

	return size;
}

bool FileAccessWindows::eof_reached() const {
	return feof(f);
}

uint64_t FileAccessWindows::get_buffer(uint8_t *p_dst, uint64_t p_length) const {
	ERR_FAIL_NULL_V(f, -1);
	ERR_FAIL_COND_V(!p_dst && p_length > 0, -1);

	if (flags == READ_WRITE || flags == WRITE_READ) {
		if (prev_op == WRITE) {
			fflush(f);
		}
		prev_op = READ;
	}

	uint64_t read = fread(p_dst, 1, p_length, f);
	check_errors();

	return read;
}

Error FileAccessWindows::get_error() const {
	return last_error;
}

Error FileAccessWindows::resize(int64_t p_length) {
	ERR_FAIL_NULL_V_MSG(f, FAILED, "File must be opened before use.");
	errno_t res = _chsize_s(_fileno(f), p_length);
	switch (res) {
		case 0:
			return OK;
		case EACCES:
		case EBADF:
			return ERR_FILE_CANT_OPEN;
		case ENOSPC:
			return ERR_OUT_OF_MEMORY;
		case EINVAL:
			return ERR_INVALID_PARAMETER;
		default:
			return FAILED;
	}
}

void FileAccessWindows::flush() {
	ERR_FAIL_NULL(f);

	fflush(f);
	if (prev_op == WRITE) {
		prev_op = 0;
	}
}

bool FileAccessWindows::store_buffer(const uint8_t *p_src, uint64_t p_length) {
	ERR_FAIL_NULL_V(f, false);
	ERR_FAIL_COND_V(!p_src && p_length > 0, false);

	if (flags == READ_WRITE || flags == WRITE_READ) {
		if (prev_op == READ) {
			if (last_error != ERR_FILE_EOF) {
				fseek(f, 0, SEEK_CUR);
			}
		}
		prev_op = WRITE;
	}

	bool res = fwrite(p_src, 1, p_length, f) == (size_t)p_length;
	check_errors(true);
	return res;
}

bool FileAccessWindows::file_exists(const String &p_name) {
	if (is_path_invalid(p_name)) {
		return false;
	}

	String filename = fix_path(p_name);
	FILE *g = _wfsopen((LPCWSTR)(filename.utf16().get_data()), L"rb", _SH_DENYNO);
	if (g == nullptr) {
		return false;
	} else {
		fclose(g);
		return true;
	}
}

uint64_t FileAccessWindows::_get_modified_time(const String &p_file) {
	if (is_path_invalid(p_file)) {
		return 0;
	}

	String file = fix_path(p_file);
	if (file.ends_with("\\") && file != "\\") {
		file = file.substr(0, file.length() - 1);
	}

	HANDLE handle = CreateFileW((LPCWSTR)(file.utf16().get_data()), GENERIC_READ, FILE_SHARE_READ, nullptr, OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS, nullptr);

	if (handle != INVALID_HANDLE_VALUE) {
		FILETIME ft_create, ft_write;

		bool status = GetFileTime(handle, &ft_create, nullptr, &ft_write);

		CloseHandle(handle);

		if (status) {
			uint64_t ret = 0;

			// If write time is invalid, fallback to creation time.
			if (ft_write.dwHighDateTime == 0 && ft_write.dwLowDateTime == 0) {
				ret = ft_create.dwHighDateTime;
				ret <<= 32;
				ret |= ft_create.dwLowDateTime;
			} else {
				ret = ft_write.dwHighDateTime;
				ret <<= 32;
				ret |= ft_write.dwLowDateTime;
			}

			const uint64_t WINDOWS_TICKS_PER_SECOND = 10000000;
			const uint64_t TICKS_TO_UNIX_EPOCH = 116444736000000000LL;

			if (ret >= TICKS_TO_UNIX_EPOCH) {
				return (ret - TICKS_TO_UNIX_EPOCH) / WINDOWS_TICKS_PER_SECOND;
			}
		}
	}

	return 0;
}

BitField<FileAccess::UnixPermissionFlags> FileAccessWindows::_get_unix_permissions(const String &p_file) {
	return 0;
}

Error FileAccessWindows::_set_unix_permissions(const String &p_file, BitField<FileAccess::UnixPermissionFlags> p_permissions) {
	return ERR_UNAVAILABLE;
}

bool FileAccessWindows::_get_hidden_attribute(const String &p_file) {
	String file = fix_path(p_file);

	DWORD attrib = GetFileAttributesW((LPCWSTR)file.utf16().get_data());
	ERR_FAIL_COND_V_MSG(attrib == INVALID_FILE_ATTRIBUTES, false, "Failed to get attributes for: " + p_file);
	return (attrib & FILE_ATTRIBUTE_HIDDEN);
}

Error FileAccessWindows::_set_hidden_attribute(const String &p_file, bool p_hidden) {
	String file = fix_path(p_file);
	const Char16String &file_utf16 = file.utf16();

	DWORD attrib = GetFileAttributesW((LPCWSTR)file_utf16.get_data());
	ERR_FAIL_COND_V_MSG(attrib == INVALID_FILE_ATTRIBUTES, FAILED, "Failed to get attributes for: " + p_file);
	BOOL ok;
	if (p_hidden) {
		ok = SetFileAttributesW((LPCWSTR)file_utf16.get_data(), attrib | FILE_ATTRIBUTE_HIDDEN);
	} else {
		ok = SetFileAttributesW((LPCWSTR)file_utf16.get_data(), attrib & ~FILE_ATTRIBUTE_HIDDEN);
	}
	ERR_FAIL_COND_V_MSG(!ok, FAILED, "Failed to set attributes for: " + p_file);

	return OK;
}

bool FileAccessWindows::_get_read_only_attribute(const String &p_file) {
	String file = fix_path(p_file);

	DWORD attrib = GetFileAttributesW((LPCWSTR)file.utf16().get_data());
	ERR_FAIL_COND_V_MSG(attrib == INVALID_FILE_ATTRIBUTES, false, "Failed to get attributes for: " + p_file);
	return (attrib & FILE_ATTRIBUTE_READONLY);
}

Error FileAccessWindows::_set_read_only_attribute(const String &p_file, bool p_ro) {
	String file = fix_path(p_file);
	const Char16String &file_utf16 = file.utf16();

	DWORD attrib = GetFileAttributesW((LPCWSTR)file_utf16.get_data());
	ERR_FAIL_COND_V_MSG(attrib == INVALID_FILE_ATTRIBUTES, FAILED, "Failed to get attributes for: " + p_file);
	BOOL ok;
	if (p_ro) {
		ok = SetFileAttributesW((LPCWSTR)file_utf16.get_data(), attrib | FILE_ATTRIBUTE_READONLY);
	} else {
		ok = SetFileAttributesW((LPCWSTR)file_utf16.get_data(), attrib & ~FILE_ATTRIBUTE_READONLY);
	}
	ERR_FAIL_COND_V_MSG(!ok, FAILED, "Failed to set attributes for: " + p_file);

	return OK;
}

void FileAccessWindows::close() {
	_close();
}

FileAccessWindows::~FileAccessWindows() {
	_close();
}

HashSet<String> FileAccessWindows::invalid_files;

void FileAccessWindows::initialize() {
	static const char *reserved_files[]{
		"con", "prn", "aux", "nul", "com0", "com1", "com2", "com3", "com4", "com5", "com6", "com7", "com8", "com9", "lpt0", "lpt1", "lpt2", "lpt3", "lpt4", "lpt5", "lpt6", "lpt7", "lpt8", "lpt9", nullptr
	};
	int reserved_file_index = 0;
	while (reserved_files[reserved_file_index] != nullptr) {
		invalid_files.insert(reserved_files[reserved_file_index]);
		reserved_file_index++;
	}

	_setmaxstdio(8192);
	print_verbose(vformat("Maximum number of file handles: %d", _getmaxstdio()));
}

void FileAccessWindows::finalize() {
	invalid_files.clear();
}

#endif // WINDOWS_ENABLED