all: change optional to result of io (#16075)

vlib/io/buffered_reader.v

@@ -107,9 +107,9 @@ pub fn (r BufferedReader) end_of_stream() bool {
 // read_line attempts to read a line from the buffered reader
 // it will read until it finds a new line character (\n) or
 // the end of stream
-pub fn (mut r BufferedReader) read_line() ?string {
+pub fn (mut r BufferedReader) read_line() !string {
 	if r.end_of_stream {
-		return none
+		return error('none')
 	}
 	mut line := []u8{}
 	for {
@@ -119,7 +119,7 @@ pub fn (mut r BufferedReader) read_line() ?string {
 				// We are at the end of the stream
 				if line.len == 0 {
 					// we had nothing so return nothing
-					return none
+					return error('none')
 				}
 				return line.bytestr()
 			}
@@ -144,5 +144,5 @@ pub fn (mut r BufferedReader) read_line() ?string {
 		line << r.buf[r.offset..i]
 		r.offset = i
 	}
-	return none
+	return error('none')
 }

vlib/io/io.v

@@ -4,7 +4,7 @@ const (
 	buf_max_len = 1024
 )
 
-pub fn cp(mut src Reader, mut dst Writer) ? {
+pub fn cp(mut src Reader, mut dst Writer) ! {
 	mut buf := []u8{len: io.buf_max_len}
 	for {
 		len := src.read(mut buf) or { break }

vlib/io/io_cp_test.v

@@ -1,13 +1,13 @@
 import io
 import os
 
-fn test_cp() ? {
+fn test_cp() {
 	mut f := os.open(@FILE) or { panic(err) }
 	defer {
 		f.close()
 	}
 	mut r := io.new_buffered_reader(reader: f)
 	mut stdout := os.stdout()
-	io.cp(mut r, mut stdout)?
+	io.cp(mut r, mut stdout)!
 	assert true
 }

vlib/io/io_test.v

@@ -21,9 +21,9 @@ fn (mut b Buf) read(mut buf []u8) !int {
 	return n
 }
 
-fn (mut w Writ) write(buf []u8) ?int {
+fn (mut w Writ) write(buf []u8) !int {
 	if buf.len <= 0 {
-		return none
+		return error('none')
 	}
 	w.bytes << buf
 	return buf.len

vlib/io/multi_writer.v

@@ -22,9 +22,9 @@ pub mut:
 // written. If any writer fails to write the full length an error is returned
 // and writing to other writers stops. If any writer returns an error the error
 // is returned immediately and writing to other writers stops.
-pub fn (mut m MultiWriter) write(buf []u8) ?int {
+pub fn (mut m MultiWriter) write(buf []u8) !int {
 	for mut w in m.writers {
-		n := w.write(buf)?
+		n := w.write(buf)!
 		if n != buf.len {
 			return error('io: incomplete write to writer of MultiWriter')
 		}

vlib/io/multi_writer_test.v

@@ -43,7 +43,7 @@ pub mut:
 	bytes []u8
 }
 
-fn (mut w TestWriter) write(buf []u8) ?int {
+fn (mut w TestWriter) write(buf []u8) !int {
 	w.bytes << buf
 	return buf.len
 }
@@ -53,7 +53,7 @@ pub mut:
 	bytes []u8
 }
 
-fn (mut w TestIncompleteWriter) write(buf []u8) ?int {
+fn (mut w TestIncompleteWriter) write(buf []u8) !int {
 	b := buf[..buf.len - 1]
 	w.bytes << b
 	return b.len
@@ -61,6 +61,6 @@ fn (mut w TestIncompleteWriter) write(buf []u8) ?int {
 
 struct TestErrorWriter {}
 
-fn (mut w TestErrorWriter) write(buf []u8) ?int {
+fn (mut w TestErrorWriter) write(buf []u8) !int {
 	return error('error writer errored')
 }

vlib/io/reader.v

@@ -44,7 +44,7 @@ mut:
 
 // read_all reads all bytes from a reader until either a 0 length read
 // or if read_to_end_of_stream is true then the end of the stream (`none`)
-pub fn read_all(config ReadAllConfig) ?[]u8 {
+pub fn read_all(config ReadAllConfig) ![]u8 {
 	mut r := config.reader
 	read_till_eof := config.read_to_end_of_stream
 
@@ -65,11 +65,11 @@ pub fn read_all(config ReadAllConfig) ?[]u8 {
 
 // read_any reads any available bytes from a reader
 // (until the reader returns a read of 0 length)
-pub fn read_any(mut r Reader) ?[]u8 {
+pub fn read_any(mut r Reader) ![]u8 {
 	mut b := []u8{len: io.read_all_len}
 	mut read := 0
 	for {
-		new_read := r.read(mut b[read..]) or { return none }
+		new_read := r.read(mut b[read..]) or { return error('none') }
 		read += new_read
 		if new_read == 0 {
 			break
@@ -83,5 +83,5 @@ pub fn read_any(mut r Reader) ?[]u8 {
 
 // RandomReader represents a stream of data that can be read from at a random location
 pub interface RandomReader {
-	read_from(pos u64, mut buf []u8) ?int
+	read_from(pos u64, mut buf []u8) !int
 }

vlib/io/readerwriter.v

@@ -18,7 +18,7 @@ pub fn (mut r ReaderWriterImpl) read(mut buf []u8) !int {
 	return r.r.read(mut buf)
 }
 
-pub fn (mut r ReaderWriterImpl) write(buf []u8) ?int {
+pub fn (mut r ReaderWriterImpl) write(buf []u8) !int {
 	return r.w.write(buf)
 }
 

vlib/io/util/util.v

@@ -14,7 +14,7 @@ pub struct TempFileOptions {
 }
 
 // temp_file returns an uniquely named, open, writable, `os.File` and it's path
-pub fn temp_file(tfo TempFileOptions) ?(os.File, string) {
+pub fn temp_file(tfo TempFileOptions) !(os.File, string) {
 	mut d := tfo.path
 	if d == '' {
 		d = os.temp_dir()
@@ -47,7 +47,7 @@ pub struct TempDirOptions {
 }
 
 // temp_dir returns an uniquely named, writable, directory path
-pub fn temp_dir(tdo TempFileOptions) ?string {
+pub fn temp_dir(tdo TempFileOptions) !string {
 	mut d := tdo.path
 	if d == '' {
 		d = os.temp_dir()

vlib/io/writer.v

@@ -3,11 +3,11 @@ module io
 // Writer represents a stream of data that can be wrote to
 pub interface Writer {
 mut:
-	write(buf []u8) ?int
+	write(buf []u8) !int
 }
 
 // RandomWriter represents a stream of data that can be wrote to
 // at a random pos
 pub interface RandomWriter {
-	write_to(pos u64, buf []u8) ?int
+	write_to(pos u64, buf []u8) !int
 }