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v/vlib/os/file.c.v

400 lines
9.5 KiB
V

module os
pub struct File {
cfile voidptr // Using void* instead of FILE*
pub:
fd int
pub mut:
is_opened bool
}
struct FileInfo {
name string
size int
}
// open_file can be used to open or create a file with custom flags and permissions and returns a `File` object.
pub fn open_file(path string, mode string, options ...int) ?File {
mut flags := 0
for m in mode {
match m {
`w` { flags |= o_create | o_trunc }
`a` { flags |= o_create | o_append }
`r` { flags |= o_rdonly }
`b` { flags |= o_binary }
`s` { flags |= o_sync }
`n` { flags |= o_nonblock }
`c` { flags |= o_noctty }
`+` { flags |= o_rdwr }
else {}
}
}
if mode == 'r+' {
flags = o_rdwr
}
if mode == 'w' {
flags = o_wronly | o_create | o_trunc
}
if mode == 'a' {
flags = o_wronly | o_create | o_append
}
mut permission := 0o666
if options.len > 0 {
permission = options[0]
}
$if windows {
if permission < 0o600 {
permission = 0x0100
} else {
permission = 0x0100 | 0x0080
}
}
mut p := path
$if windows {
p = path.replace('/', '\\')
}
fd := C.open(charptr(p.str), flags, permission)
if fd == -1 {
return error(posix_get_error_msg(C.errno))
}
cfile := C.fdopen(fd, charptr(mode.str))
if isnil(cfile) {
return error('Failed to open or create file "$path"')
}
return File{
cfile: cfile
fd: fd
is_opened: true
}
}
// open tries to open a file for reading and returns back a read-only `File` object.
pub fn open(path string) ?File {
/*
$if linux {
$if !android {
fd := C.syscall(sys_open, path.str, 511)
if fd == -1 {
return error('failed to open file "$path"')
}
return File{
fd: fd
is_opened: true
}
}
}
*/
cfile := vfopen(path, 'rb') ?
fd := fileno(cfile)
return File{
cfile: cfile
fd: fd
is_opened: true
}
}
// create creates or opens a file at a specified location and returns a write-only `File` object.
pub fn create(path string) ?File {
/*
// NB: android/termux/bionic is also a kind of linux,
// but linux syscalls there sometimes fail,
// while the libc version should work.
$if linux {
$if !android {
//$if macos {
// fd = C.syscall(398, path.str, 0x601, 0x1b6)
//}
//$if linux {
fd = C.syscall(sys_creat, path.str, 511)
//}
if fd == -1 {
return error('failed to create file "$path"')
}
file = File{
fd: fd
is_opened: true
}
return file
}
}
*/
cfile := vfopen(path, 'wb') ?
fd := fileno(cfile)
return File{
cfile: cfile
fd: fd
is_opened: true
}
}
// open_stdin - return an os.File for stdin, so that you can use .get_line on it too.
pub fn open_stdin() File {
return File{
fd: 0
cfile: C.stdin
is_opened: true
}
}
// **************************** Write ops ***************************
// write implements the Writer interface.
// It returns how many bytes were actually written.
pub fn (mut f File) write(buf []byte) ?int {
if !f.is_opened {
return error('file is not opened')
}
/*
$if linux {
$if !android {
res := C.syscall(sys_write, f.fd, s.str, s.len)
return res
}
}
*/
written := int(C.fwrite(buf.data, buf.len, 1, f.cfile))
if written == 0 && buf.len != 0 {
return error('0 bytes written')
}
return written
}
// writeln writes the string `s` into the file, and appends a \n character.
// It returns how many bytes were written, including the \n character.
pub fn (mut f File) writeln(s string) ?int {
if !f.is_opened {
return error('file is not opened')
}
/*
$if linux {
$if !android {
snl := s + '\n'
C.syscall(sys_write, f.fd, snl.str, snl.len)
return
}
}
*/
// TODO perf
written := int(C.fwrite(s.str, s.len, 1, f.cfile))
if written == 0 && s.len != 0 {
return error('0 bytes written')
}
x := C.fputs('\n', f.cfile)
if x < 0 {
return error('could not add newline')
}
return (written + 1)
}
// write_string writes the string `s` into the file
// It returns how many bytes were actually written.
pub fn (mut f File) write_string(s string) ?int {
if !f.is_opened {
return error('file is not opened')
}
// TODO perf
written := int(C.fwrite(s.str, s.len, 1, f.cfile))
if written == 0 && s.len != 0 {
return error('0 bytes written')
}
return written
}
// write_to implements the RandomWriter interface.
// It returns how many bytes were actually written.
// It resets the seek position to the end of the file.
pub fn (mut f File) write_to(pos int, buf []byte) ?int {
if !f.is_opened {
return error('file is not opened')
}
C.fseek(f.cfile, pos, C.SEEK_SET)
res := int(C.fwrite(buf.data, 1, buf.len, f.cfile))
if res == 0 && buf.len != 0 {
return error('0 bytes written')
}
C.fseek(f.cfile, 0, C.SEEK_END)
return res
}
// write_bytes writes `size` bytes to the file, starting from the address in `data`.
// NB: write_bytes is unsafe and should be used carefully, since if you pass invalid
// pointers to it, it will cause your programs to segfault.
[unsafe]
pub fn (mut f File) write_bytes(data voidptr, size int) int {
return int(C.fwrite(data, 1, size, f.cfile))
}
// write_bytes_at writes `size` bytes to the file, starting from the address in `data`,
// at byte offset `pos`, counting from the start of the file (pos 0).
// NB: write_bytes_at is unsafe and should be used carefully, since if you pass invalid
// pointers to it, it will cause your programs to segfault.
[unsafe]
pub fn (mut f File) write_bytes_at(data voidptr, size int, pos int) int {
C.fseek(f.cfile, pos, C.SEEK_SET)
res := int(C.fwrite(data, 1, size, f.cfile))
C.fseek(f.cfile, 0, C.SEEK_END)
return res
}
// **************************** Read ops ***************************
// read_bytes reads bytes from the beginning of the file.
// Utility method, same as .read_bytes_at(size, 0).
pub fn (f &File) read_bytes(size int) []byte {
return f.read_bytes_at(size, 0)
}
// read_bytes_at reads `size` bytes at the given position in the file.
pub fn (f &File) read_bytes_at(size int, pos int) []byte {
mut arr := []byte{len: size}
nreadbytes := f.read_bytes_into(pos, mut arr) or {
// return err
return []
}
return arr[0..nreadbytes]
}
// read_bytes_into fills `buf` with bytes at the given position in the file.
// `buf` *must* have length greater than zero.
// Returns the number of read bytes, or an error.
pub fn (f &File) read_bytes_into(pos int, mut buf []byte) ?int {
if buf.len == 0 {
panic(@FN + ': `buf.len` == 0')
}
// Note: fseek errors if pos == os.file_size, which we accept
C.fseek(f.cfile, pos, C.SEEK_SET)
// errno is only set if fread fails, so clear it first to tell
C.errno = 0
nbytes := int(C.fread(buf.data, 1, buf.len, f.cfile))
if C.errno != 0 {
return error(posix_get_error_msg(C.errno))
}
$if debug {
C.fseek(f.cfile, 0, C.SEEK_SET)
}
return nbytes
}
// read implements the Reader interface.
pub fn (f &File) read(mut buf []byte) ?int {
if buf.len == 0 {
return 0
}
C.errno = 0
nbytes := int(C.fread(buf.data, 1, buf.len, f.cfile))
if C.errno != 0 {
return error(posix_get_error_msg(C.errno))
}
return nbytes
}
// read_at reads `buf.len` bytes starting at file byte offset `pos`, in `buf`.
pub fn (f &File) read_at(pos int, mut buf []byte) ?int {
if buf.len == 0 {
return 0
}
C.fseek(f.cfile, pos, C.SEEK_SET)
C.errno = 0
nbytes := int(C.fread(buf.data, 1, buf.len, f.cfile))
if C.errno != 0 {
return error(posix_get_error_msg(C.errno))
}
return nbytes
}
// **************************** Utility ops ***********************
// flush writes any buffered unwritten data left in the file stream.
pub fn (mut f File) flush() {
if !f.is_opened {
return
}
C.fflush(f.cfile)
}
// write_str writes the bytes of a string into a file,
// *including* the terminating 0 byte.
pub fn (mut f File) write_str(s string) ? {
if !f.is_opened {
return error('file is closed')
}
f.write(s.bytes()) ?
}
// read_struct reads a single struct of type `T`
pub fn (mut f File) read_struct<T>(mut t T) ? {
if !f.is_opened {
return none
}
tsize := int(sizeof(*t))
if tsize == 0 {
return none
}
C.errno = 0
nbytes := int(C.fread(t, 1, tsize, f.cfile))
if C.errno != 0 {
return error(posix_get_error_msg(C.errno))
}
if nbytes != tsize {
return error_with_code('incomplete struct read', nbytes)
}
}
// read_struct_at reads a single struct of type `T` at position specified in file
pub fn (mut f File) read_struct_at<T>(mut t T, pos int) ? {
if !f.is_opened {
return none
}
tsize := int(sizeof(*t))
if tsize == 0 {
return none
}
C.errno = 0
C.fseek(f.cfile, pos, C.SEEK_SET)
nbytes := int(C.fread(t, 1, tsize, f.cfile))
C.fseek(f.cfile, 0, C.SEEK_END)
if C.errno != 0 {
return error(posix_get_error_msg(C.errno))
}
if nbytes != tsize {
return error_with_code('incomplete struct read', nbytes)
}
}
// write_struct writes a single struct of type `T`
pub fn (mut f File) write_struct<T>(t &T) ? {
if !f.is_opened {
return error('file is not opened')
}
tsize := int(sizeof(*t))
if tsize == 0 {
return error('struct size is 0')
}
C.errno = 0
nbytes := int(C.fwrite(t, 1, tsize, f.cfile))
if C.errno != 0 {
return error(posix_get_error_msg(C.errno))
}
if nbytes != tsize {
return error_with_code('incomplete struct write', nbytes)
}
}
// write_struct_at writes a single struct of type `T` at position specified in file
pub fn (mut f File) write_struct_at<T>(t &T, pos int) ? {
if !f.is_opened {
return error('file is not opened')
}
tsize := int(sizeof(*t))
if tsize == 0 {
return error('struct size is 0')
}
C.errno = 0
C.fseek(f.cfile, pos, C.SEEK_SET)
nbytes := int(C.fwrite(t, 1, tsize, f.cfile))
C.fseek(f.cfile, 0, C.SEEK_END)
if C.errno != 0 {
return error(posix_get_error_msg(C.errno))
}
if nbytes != tsize {
return error_with_code('incomplete struct write', nbytes)
}
}