/
file.go
372 lines (324 loc) · 7.05 KB
/
file.go
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// Copyright Suneido Software Corp. All rights reserved.
// Governed by the MIT license found in the LICENSE file.
package builtin
import (
"bufio"
"io"
"os"
"strings"
"sync"
"sync/atomic"
. "github.com/apmckinlay/gsuneido/core"
"github.com/apmckinlay/gsuneido/core/types"
"github.com/apmckinlay/gsuneido/util/hacks"
)
type iFile interface {
io.ReadWriteCloser
io.Seeker
}
type suFile struct {
ValueBase[*suFile]
f iFile
r *bufio.Reader // only one of r or w will be used
w *bufio.Writer
name string
mode string
// tell is used to track our own position in the file.
// We can't use f.Tell() because of buffering.
// Any reads or writes must update this.
// Not used for "a" (append) mode.
tell int64
bufs sync.Pool
}
var nFile atomic.Int32
var _ = AddInfo("builtin.nFile", &nFile)
var _ = builtin(File, "(filename, mode='r', block=false)")
func File(th *Thread, args []Value) Value {
name := ToStr(args[0])
mode := ToStr(args[1])
sf := newSuFile(name, mode)
nFile.Add(1)
if args[2] == False {
return sf
}
// block form
defer sf.close()
return th.Call(args[2], sf)
}
func newSuFile(name, mode string) *suFile {
var flag int
switch mode {
case "r":
flag = os.O_RDONLY
case "a":
flag = os.O_WRONLY | os.O_CREATE
case "w":
flag = os.O_WRONLY | os.O_CREATE | os.O_TRUNC
default:
panic("File: invalid mode")
}
var f iFile
f, err := os.OpenFile(name, flag, 0644)
if err != nil {
panic("File: can't " + err.Error())
}
if mode == "a" {
f = appender{f}
}
sf := &suFile{name: name, mode: mode, f: f}
if sf.mode == "r" {
sf.r = bufio.NewReader(f)
} else { // "w" or "a"
sf.w = bufio.NewWriter(f)
}
return sf
}
// reset is called by Seek to reset buffering
func (sf *suFile) reset() {
if sf.mode == "r" {
sf.r.Reset(sf.f)
} else {
err := sf.w.Flush()
sf.w.Reset(sf.f)
if err != nil {
panic("File: " + err.Error())
}
}
}
func (sf *suFile) size() int64 {
info, err := sf.f.(*os.File).Stat()
if err != nil {
panic("File: " + err.Error())
}
return info.Size()
}
func (sf *suFile) close() {
nFile.Add(-1)
if sf.mode != "r" {
err := sf.w.Flush()
if err != nil {
defer panic("File: " + err.Error())
}
}
err := sf.f.Close()
sf.f = nil
if err != nil {
panic("File: " + err.Error())
}
}
var _ Value = (*suFile)(nil)
func (sf *suFile) String() string {
return "File(" + sf.name + ", " + sf.mode + ")"
}
func (*suFile) Type() types.Type {
return types.File
}
func (sf *suFile) Equal(other any) bool {
return sf == other
}
func (*suFile) Lookup(_ *Thread, method string) Callable {
return suFileMethods[method]
}
const MaxLine = 4000
var suFileMethods = methods()
var _ = method(file_Close, "()")
func file_Close(this Value) Value {
sfOpen(this).close()
return nil
}
var _ = method(file_Flush, "()")
func file_Flush(this Value) Value {
err := sfOpenWrite(this).w.Flush()
if err != nil {
panic("File: " + err.Error())
}
return nil
}
var _ = method(file_Read, "(nbytes=false)")
func file_Read(this, arg Value) Value {
sf := sfOpenRead(this)
n := int(sf.size() - sf.tell) // remaining
if n == 0 { // at end
return False
}
if arg != False {
if m := ToInt(arg); m < n {
n = m
}
}
buf := make([]byte, n)
_, err := io.ReadFull(sf.r, buf)
sf.tell += int64(n)
if err != nil {
panic("File: Read: " + err.Error())
}
return SuStr(hacks.BStoS(buf))
}
var _ = method(file_CopyTo, "(dest, nbytes)")
func file_CopyTo(th *Thread, this Value, args []Value) Value {
src := sfOpenRead(this)
dst := sfOpenWrite(args[0])
n := ToInt(args[1])
const max = 64 * 1042
if n < 0 || max < n {
panic("File: CopyTo: invalid nbytes")
}
buf := src.getBuf(n)
defer src.bufs.Put(buf)
nr, err := io.ReadFull(src.f, buf[:n])
if err != nil && err != io.ErrUnexpectedEOF && err != io.EOF {
panic("File: CopyTo: " + err.Error())
}
_, err = dst.f.Write(buf[:nr])
if err != nil {
panic("File: CopyTo: " + err.Error())
}
if nr != n {
th.ReturnThrow = true
}
return IntVal(nr)
}
func (sf *suFile) getBuf(n int) []byte {
b := sf.bufs.Get()
if b != nil && cap(b.([]byte)) >= n {
return b.([]byte)[:n]
}
return make([]byte, n)
}
var _ = method(file_Readline, "()")
func file_Readline(this Value) Value {
sf := sfOpenRead(this)
val, nr := readline(sf.r, "File: Readline: ")
sf.tell += int64(nr)
return val
}
var _ = method(file_Seek, "(offset, origin='set')")
func file_Seek(this, arg1, arg2 Value) Value {
sf := sfOpen(this)
if sf.mode == "a" {
panic("File: Seek: invalid with mode 'a'")
}
sf.reset()
offset := ToInt64(arg1)
switch ToStr(arg2) {
case "set":
//
case "cur":
offset += sf.tell
case "end":
offset += sf.size()
default:
panic("File: Seek: origin must be 'set', 'end', or 'cur'")
}
_, err := sf.f.Seek(offset, io.SeekStart)
if err != nil {
panic("File: Seek: " + err.Error())
}
sf.tell = offset
return nil
}
var _ = method(file_Tell, "()")
func file_Tell(this Value) Value {
sf := sfOpen(this)
if sf.mode == "a" {
panic("File: Tell: invalid with mode 'a'")
}
return Int64Val(sf.tell)
}
var _ = method(file_Write, "(string)")
func file_Write(this, arg Value) Value {
s := AsStr(arg)
sf := sfOpenWrite(this)
_, err := sf.w.WriteString(s)
if err != nil {
panic("File: Write: " + err.Error())
}
sf.tell += int64(len(s))
return arg
}
var _ = method(file_Writeline, "(string)")
func file_Writeline(this, arg Value) Value {
s := AsStr(arg)
sf := sfOpenWrite(this)
sf.w.WriteString(s)
_, err := sf.w.WriteString("\r\n")
if err != nil {
panic("File: Writeline: " + err.Error())
}
sf.tell += int64(len(s) + 2)
return arg
}
func sfOpen(this Value) *suFile {
sf := this.(*suFile)
if sf.f == nil {
panic("can't use a closed file: " + sf.name)
}
return sf
}
func sfOpenRead(this Value) *suFile {
sf := sfOpen(this)
if sf.mode != "r" {
panic("File: can't read a file opened for writing")
}
return sf
}
func sfOpenWrite(this Value) *suFile {
sf := sfOpen(this)
if sf.mode == "r" {
panic("File: can't write a file opened for reading")
}
return sf
}
func Readline(rdr io.Reader, errPrefix string) Value {
val, _ := readline(rdr, errPrefix)
return val
}
func readline(rdr io.Reader, errPrefix string) (Value, int) {
nr := 0
var buf strings.Builder
b := make([]byte, 1)
for {
_, err := rdr.Read(b)
if err == io.EOF {
if buf.Len() == 0 {
return False, nr
}
break
}
if err != nil {
panic(errPrefix + err.Error())
}
nr++
if b[0] == '\n' {
break
}
if buf.Len() < MaxLine {
buf.WriteByte(b[0])
}
}
s := buf.String()
s = strings.TrimRight(s, "\r")
return SuStr(s), nr
}
// appender is a workaround for a Windows bug
// where normal append doesn't work on RDP shares.
// e.g. \\tsclient\C\...
type appender struct {
f iFile
}
func (a appender) Write(buf []byte) (int, error) {
_, err := a.f.Seek(0, io.SeekEnd)
if err != nil {
panic("File: " + err.Error())
}
return a.f.Write(buf)
}
func (a appender) Read([]byte) (int, error) {
panic("appender Read not implemented")
}
func (a appender) Seek(int64, int) (int64, error) {
panic("appender Seek not implemented")
}
func (a appender) Close() error {
return a.f.Close()
}