zig/std/os/file.zig

355 lines
14 KiB
Zig

const std = @import("../index.zig");
const builtin = @import("builtin");
const os = std.os;
const mem = std.mem;
const math = std.math;
const assert = std.debug.assert;
const posix = os.posix;
const windows = os.windows;
const Os = builtin.Os;
const is_posix = builtin.os != builtin.Os.windows;
const is_windows = builtin.os == builtin.Os.windows;
pub const File = struct {
/// The OS-specific file descriptor or file handle.
handle: os.FileHandle,
const OpenError = os.WindowsOpenError || os.PosixOpenError;
/// `path` needs to be copied in memory to add a null terminating byte, hence the allocator.
/// Call close to clean up.
pub fn openRead(allocator: &mem.Allocator, path: []const u8) OpenError!File {
if (is_posix) {
const flags = posix.O_LARGEFILE|posix.O_RDONLY;
const fd = try os.posixOpen(allocator, path, flags, 0);
return openHandle(fd);
} else if (is_windows) {
const handle = try os.windowsOpen(allocator, path, windows.GENERIC_READ, windows.FILE_SHARE_READ,
windows.OPEN_EXISTING, windows.FILE_ATTRIBUTE_NORMAL);
return openHandle(handle);
} else {
@compileError("TODO implement openRead for this OS");
}
}
/// Calls `openWriteMode` with os.default_file_mode for the mode.
pub fn openWrite(allocator: &mem.Allocator, path: []const u8) OpenError!File {
return openWriteMode(allocator, path, os.default_file_mode);
}
/// If the path does not exist it will be created.
/// If a file already exists in the destination it will be truncated.
/// `path` needs to be copied in memory to add a null terminating byte, hence the allocator.
/// Call close to clean up.
pub fn openWriteMode(allocator: &mem.Allocator, path: []const u8, file_mode: os.FileMode) OpenError!File {
if (is_posix) {
const flags = posix.O_LARGEFILE|posix.O_WRONLY|posix.O_CREAT|posix.O_CLOEXEC|posix.O_TRUNC;
const fd = try os.posixOpen(allocator, path, flags, file_mode);
return openHandle(fd);
} else if (is_windows) {
const handle = try os.windowsOpen(allocator, path, windows.GENERIC_WRITE,
windows.FILE_SHARE_WRITE|windows.FILE_SHARE_READ|windows.FILE_SHARE_DELETE,
windows.CREATE_ALWAYS, windows.FILE_ATTRIBUTE_NORMAL);
return openHandle(handle);
} else {
@compileError("TODO implement openWriteMode for this OS");
}
}
/// If the path does not exist it will be created.
/// If a file already exists in the destination this returns OpenError.PathAlreadyExists
/// `path` needs to be copied in memory to add a null terminating byte, hence the allocator.
/// Call close to clean up.
pub fn openWriteNoClobber(allocator: &mem.Allocator, path: []const u8, file_mode: os.FileMode) OpenError!File {
if (is_posix) {
const flags = posix.O_LARGEFILE|posix.O_WRONLY|posix.O_CREAT|posix.O_CLOEXEC|posix.O_EXCL;
const fd = try os.posixOpen(allocator, path, flags, file_mode);
return openHandle(fd);
} else if (is_windows) {
const handle = try os.windowsOpen(allocator, path, windows.GENERIC_WRITE,
windows.FILE_SHARE_WRITE|windows.FILE_SHARE_READ|windows.FILE_SHARE_DELETE,
windows.CREATE_NEW, windows.FILE_ATTRIBUTE_NORMAL);
return openHandle(handle);
} else {
@compileError("TODO implement openWriteMode for this OS");
}
}
pub fn openHandle(handle: os.FileHandle) File {
return File {
.handle = handle,
};
}
pub fn access(allocator: &mem.Allocator, path: []const u8, file_mode: os.FileMode) !bool {
const path_with_null = try std.cstr.addNullByte(allocator, path);
defer allocator.free(path_with_null);
if (is_posix) {
// mode is ignored and is always F_OK for now
const result = posix.access(path_with_null.ptr, posix.F_OK);
const err = posix.getErrno(result);
if (err > 0) {
return switch (err) {
posix.EACCES => error.PermissionDenied,
posix.EROFS => error.PermissionDenied,
posix.ELOOP => error.PermissionDenied,
posix.ETXTBSY => error.PermissionDenied,
posix.ENOTDIR => error.NotFound,
posix.ENOENT => error.NotFound,
posix.ENAMETOOLONG => error.NameTooLong,
posix.EINVAL => error.BadMode,
posix.EFAULT => error.BadPathName,
posix.EIO => error.Io,
posix.ENOMEM => error.SystemResources,
else => os.unexpectedErrorPosix(err),
};
}
return true;
} else if (is_windows) {
if (os.windows.PathFileExists(path_with_null.ptr) == os.windows.TRUE) {
return true;
}
const err = windows.GetLastError();
return switch (err) {
windows.ERROR.FILE_NOT_FOUND => error.NotFound,
windows.ERROR.ACCESS_DENIED => error.PermissionDenied,
else => os.unexpectedErrorWindows(err),
};
} else {
@compileError("TODO implement access for this OS");
}
}
/// Upon success, the stream is in an uninitialized state. To continue using it,
/// you must use the open() function.
pub fn close(self: &File) void {
os.close(self.handle);
self.handle = undefined;
}
/// Calls `os.isTty` on `self.handle`.
pub fn isTty(self: &File) bool {
return os.isTty(self.handle);
}
pub fn seekForward(self: &File, amount: isize) !void {
switch (builtin.os) {
Os.linux, Os.macosx, Os.ios => {
const result = posix.lseek(self.handle, amount, posix.SEEK_CUR);
const err = posix.getErrno(result);
if (err > 0) {
return switch (err) {
posix.EBADF => error.BadFd,
posix.EINVAL => error.Unseekable,
posix.EOVERFLOW => error.Unseekable,
posix.ESPIPE => error.Unseekable,
posix.ENXIO => error.Unseekable,
else => os.unexpectedErrorPosix(err),
};
}
},
Os.windows => {
if (windows.SetFilePointerEx(self.handle, amount, null, windows.FILE_CURRENT) == 0) {
const err = windows.GetLastError();
return switch (err) {
windows.ERROR.INVALID_PARAMETER => error.BadFd,
else => os.unexpectedErrorWindows(err),
};
}
},
else => @compileError("unsupported OS"),
}
}
pub fn seekTo(self: &File, pos: usize) !void {
switch (builtin.os) {
Os.linux, Os.macosx, Os.ios => {
const ipos = try math.cast(isize, pos);
const result = posix.lseek(self.handle, ipos, posix.SEEK_SET);
const err = posix.getErrno(result);
if (err > 0) {
return switch (err) {
posix.EBADF => error.BadFd,
posix.EINVAL => error.Unseekable,
posix.EOVERFLOW => error.Unseekable,
posix.ESPIPE => error.Unseekable,
posix.ENXIO => error.Unseekable,
else => os.unexpectedErrorPosix(err),
};
}
},
Os.windows => {
const ipos = try math.cast(isize, pos);
if (windows.SetFilePointerEx(self.handle, ipos, null, windows.FILE_BEGIN) == 0) {
const err = windows.GetLastError();
return switch (err) {
windows.ERROR.INVALID_PARAMETER => error.BadFd,
else => os.unexpectedErrorWindows(err),
};
}
},
else => @compileError("unsupported OS: " ++ @tagName(builtin.os)),
}
}
pub fn getPos(self: &File) !usize {
switch (builtin.os) {
Os.linux, Os.macosx, Os.ios => {
const result = posix.lseek(self.handle, 0, posix.SEEK_CUR);
const err = posix.getErrno(result);
if (err > 0) {
return switch (err) {
posix.EBADF => error.BadFd,
posix.EINVAL => error.Unseekable,
posix.EOVERFLOW => error.Unseekable,
posix.ESPIPE => error.Unseekable,
posix.ENXIO => error.Unseekable,
else => os.unexpectedErrorPosix(err),
};
}
return result;
},
Os.windows => {
var pos : windows.LARGE_INTEGER = undefined;
if (windows.SetFilePointerEx(self.handle, 0, &pos, windows.FILE_CURRENT) == 0) {
const err = windows.GetLastError();
return switch (err) {
windows.ERROR.INVALID_PARAMETER => error.BadFd,
else => os.unexpectedErrorWindows(err),
};
}
assert(pos >= 0);
if (@sizeOf(@typeOf(pos)) > @sizeOf(usize)) {
if (pos > @maxValue(usize)) {
return error.FilePosLargerThanPointerRange;
}
}
return usize(pos);
},
else => @compileError("unsupported OS"),
}
}
pub fn getEndPos(self: &File) !usize {
if (is_posix) {
var stat: posix.Stat = undefined;
const err = posix.getErrno(posix.fstat(self.handle, &stat));
if (err > 0) {
return switch (err) {
posix.EBADF => error.BadFd,
posix.ENOMEM => error.SystemResources,
else => os.unexpectedErrorPosix(err),
};
}
return usize(stat.size);
} else if (is_windows) {
var file_size: windows.LARGE_INTEGER = undefined;
if (windows.GetFileSizeEx(self.handle, &file_size) == 0) {
const err = windows.GetLastError();
return switch (err) {
else => os.unexpectedErrorWindows(err),
};
}
if (file_size < 0)
return error.Overflow;
return math.cast(usize, u64(file_size));
} else {
@compileError("TODO support getEndPos on this OS");
}
}
pub const ModeError = error {
BadFd,
SystemResources,
Unexpected,
};
fn mode(self: &File) ModeError!os.FileMode {
if (is_posix) {
var stat: posix.Stat = undefined;
const err = posix.getErrno(posix.fstat(self.handle, &stat));
if (err > 0) {
return switch (err) {
posix.EBADF => error.BadFd,
posix.ENOMEM => error.SystemResources,
else => os.unexpectedErrorPosix(err),
};
}
// TODO: we should be able to cast u16 to ModeError!u32, making this
// explicit cast not necessary
return os.FileMode(stat.mode);
} else if (is_windows) {
return {};
} else {
@compileError("TODO support file mode on this OS");
}
}
pub const ReadError = error {};
pub fn read(self: &File, buffer: []u8) !usize {
if (is_posix) {
var index: usize = 0;
while (index < buffer.len) {
const amt_read = posix.read(self.handle, &buffer[index], buffer.len - index);
const read_err = posix.getErrno(amt_read);
if (read_err > 0) {
switch (read_err) {
posix.EINTR => continue,
posix.EINVAL => unreachable,
posix.EFAULT => unreachable,
posix.EBADF => return error.BadFd,
posix.EIO => return error.Io,
else => return os.unexpectedErrorPosix(read_err),
}
}
if (amt_read == 0) return index;
index += amt_read;
}
return index;
} else if (is_windows) {
var index: usize = 0;
while (index < buffer.len) {
const want_read_count = windows.DWORD(math.min(windows.DWORD(@maxValue(windows.DWORD)), buffer.len - index));
var amt_read: windows.DWORD = undefined;
if (windows.ReadFile(self.handle, @ptrCast(&c_void, &buffer[index]), want_read_count, &amt_read, null) == 0) {
const err = windows.GetLastError();
return switch (err) {
windows.ERROR.OPERATION_ABORTED => continue,
windows.ERROR.BROKEN_PIPE => return index,
else => os.unexpectedErrorWindows(err),
};
}
if (amt_read == 0) return index;
index += amt_read;
}
return index;
} else {
unreachable;
}
}
pub const WriteError = os.WindowsWriteError || os.PosixWriteError;
fn write(self: &File, bytes: []const u8) WriteError!void {
if (is_posix) {
try os.posixWrite(self.handle, bytes);
} else if (is_windows) {
try os.windowsWrite(self.handle, bytes);
} else {
@compileError("Unsupported OS");
}
}
};