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Add io.popen implementation #141

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22 changes: 0 additions & 22 deletions doc_test.go
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It fails now.

$ go test ./...
# github.com/Shopify/go-lua_test
# [github.com/Shopify/go-lua_test]
./doc_test.go:8:1: ExampleFunction should be niladic
./doc_test.go:8:1: ExampleFunction should return nothing
FAIL    github.com/Shopify/go-lua [build failed]
FAIL

This file was deleted.

145 changes: 98 additions & 47 deletions io.go
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Original file line number Diff line number Diff line change
Expand Up @@ -5,6 +5,7 @@ import (
"io"
"io/ioutil"
"os"
"os/exec"
)

const fileHandle = "FILE*"
Expand All @@ -13,6 +14,8 @@ const output = "_IO_output"

type stream struct {
f *os.File
r io.Reader
w io.Writer
close Function
}

Expand All @@ -27,15 +30,31 @@ func toFile(l *State) *os.File {
return s.f
}

func newStream(l *State, f *os.File, close Function) *stream {
s := &stream{f: f, close: close}
func toReader(l *State) io.Reader {
s := toStream(l)
if s.r != nil {
return s.r
}
return s.f
}

func toWriter(l *State) io.Writer {
s := toStream(l)
if s.w != nil {
return s.w
}
return s.f
}

func newStream(l *State, f *os.File, r io.Reader, w io.Writer, close Function) *stream {
s := &stream{f: f, r: r, w: w, close: close}
l.PushUserData(s)
SetMetaTableNamed(l, fileHandle)
return s
}

func newFile(l *State) *stream {
return newStream(l, nil, func(l *State) int { return FileResult(l, toStream(l).f.Close(), "") })
return newStream(l, nil, nil, nil, func(l *State) int { return FileResult(l, toStream(l).f.Close(), "") })
}

func ioFile(l *State, name string) *os.File {
Expand Down Expand Up @@ -85,17 +104,17 @@ func close(l *State) int {
if l.IsNone(1) {
l.Field(RegistryIndex, output)
}
toFile(l)
return closeHelper(l)
}

func write(l *State, f *os.File, argIndex int) int {
var err error
writer := toWriter(l)
for argCount := l.Top(); argIndex < argCount && err == nil; argIndex++ {
if n, ok := l.ToNumber(argIndex); ok {
_, err = f.WriteString(numberToString(n))
_, err = writer.Write([]byte(numberToString(n)))
} else {
_, err = f.WriteString(CheckString(l, argIndex))
_, err = writer.Write([]byte(CheckString(l, argIndex)))
}
}
if err == nil {
Expand All @@ -104,6 +123,16 @@ func write(l *State, f *os.File, argIndex int) int {
return FileResult(l, err, "")
}

func read(l *State, f *os.File, argIndex int) int {
reader := toReader(l)
buf, err := io.ReadAll(reader)
if err != nil && err != io.EOF {
return FileResult(l, err, "")
}
l.PushString(string(buf))
return 1
}

func readNumber(l *State, f *os.File) (err error) {
var n float64
if _, err = fmt.Fscanf(f, "%f", &n); err == nil {
Expand All @@ -114,25 +143,6 @@ func readNumber(l *State, f *os.File) (err error) {
return
}

func read(l *State, f *os.File, argIndex int) int {
resultCount := 0
var err error
if argCount := l.Top() - 1; argCount == 0 {
// err = readLineHelper(l, f, true)
resultCount = argIndex + 1
} else {
// TODO
}
if err != nil {
return FileResult(l, err, "")
}
if err == io.EOF {
l.Pop(1)
l.PushNil()
}
return resultCount - argIndex
}

func readLine(l *State) int {
s := l.ToUserData(UpValueIndex(1)).(*stream)
argCount, _ := l.ToInteger(UpValueIndex(2))
Expand Down Expand Up @@ -227,7 +237,58 @@ var ioLibrary = []RegistryFunction{
return FileResult(l, err, name)
}},
{"output", ioFileHelper(output, "w")},
{"popen", func(l *State) int { Errorf(l, "'popen' not supported"); panic("unreachable") }},
{"popen", func(l *State) int {
cmdStr := CheckString(l, 1)
mode := OptString(l, 2, "r")
var r io.Reader
var w io.Writer
var closer io.Closer
var cmd *exec.Cmd
var err error

switch mode {
case "r":
cmd = exec.Command("sh", "-c", cmdStr)
stdout, e := cmd.StdoutPipe()
if e != nil {
l.PushNil()
l.PushString(e.Error())
return 2
}
if err = cmd.Start(); err != nil {
l.PushNil()
l.PushString(err.Error())
return 2
}
r = stdout
closer = stdout
case "w":
cmd = exec.Command("sh", "-c", cmdStr)
stdin, e := cmd.StdinPipe()
if e != nil {
l.PushNil()
l.PushString(e.Error())
return 2
}
if err = cmd.Start(); err != nil {
l.PushNil()
l.PushString(err.Error())
return 2
}
w = stdin
closer = stdin
default:
Errorf(l, "'popen' only supports 'r' or 'w' mode")
panic("unreachable")
}

newStream(l, nil, r, w, func(l *State) int {
err := closer.Close()
cmd.Wait()
return FileResult(l, err, "")
})
return 1
}},
{"read", func(l *State) int { return read(l, ioFile(l, input), 1) }},
{"tmpfile", func(l *State) int {
s := newFile(l)
Expand All @@ -250,13 +311,17 @@ var ioLibrary = []RegistryFunction{
return 1
}},
{"write", func(l *State) int { return write(l, ioFile(l, output), 1) }},
// Register standard files directly in ioLibrary
{"stdin", func(l *State) int { newStream(l, os.Stdin, nil, nil, dontClose); return 1 }},
{"stdout", func(l *State) int { newStream(l, os.Stdout, nil, nil, dontClose); return 1 }},
{"stderr", func(l *State) int { newStream(l, os.Stderr, nil, nil, dontClose); return 1 }},
}

var fileHandleMethods = []RegistryFunction{
{"close", close},
{"flush", func(l *State) int { return FileResult(l, toFile(l).Sync(), "") }},
{"lines", func(l *State) int { toFile(l); lines(l, false); return 1 }},
{"read", func(l *State) int { return read(l, toFile(l), 2) }},
{"read", func(l *State) int { return read(l, nil, 2) }},
{"seek", func(l *State) int {
whence := []int{os.SEEK_SET, os.SEEK_CUR, os.SEEK_END}
f := toFile(l)
Expand All @@ -272,13 +337,10 @@ var fileHandleMethods = []RegistryFunction{
return 1
}},
{"setvbuf", func(l *State) int { // Files are unbuffered in Go. Fake support for now.
// f := toFile(l)
// op := CheckOption(l, 2, "", []string{"no", "full", "line"})
// size := OptInteger(l, 3, 1024)
// TODO err := setvbuf(f, nil, mode[op], size)
// TODO: Implement setvbuf if needed in the future
return FileResult(l, nil, "")
}},
{"write", func(l *State) int { l.PushValue(1); return write(l, toFile(l), 2) }},
{"write", func(l *State) int { l.PushValue(1); return write(l, nil, 2) }},
// {"__gc", },
{"__tostring", func(l *State) int {
if s := toStream(l); s.close == nil {
Expand All @@ -297,28 +359,17 @@ func dontClose(l *State) int {
return 2
}

func registerStdFile(l *State, f *os.File, reg, name string) {
newStream(l, f, dontClose)
if reg != "" {
l.PushValue(-1)
l.SetField(RegistryIndex, reg)
}
l.SetField(-2, name)
}

// IOOpen opens the io library. Usually passed to Require.
func IOOpen(l *State) int {
NewLibrary(l, ioLibrary)

// First create the file handle metatable
NewMetaTable(l, fileHandle)
l.PushValue(-1)
l.SetField(-2, "__index")
SetFunctions(l, fileHandleMethods, 0)
l.Pop(1)

registerStdFile(l, os.Stdin, input, "stdin")
registerStdFile(l, os.Stdout, output, "stdout")
registerStdFile(l, os.Stderr, "", "stderr")

// Then create the io library
NewLibrary(l, ioLibrary)

return 1
}
22 changes: 22 additions & 0 deletions vm_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -458,3 +458,25 @@ func TestLocIsCorrectOnError(t *testing.T) {
}
}
}

func TestIOPopenRead(t *testing.T) {
s := `
local f = io.popen("echo popen_read_test", "r")
assert(f ~= nil, "io.popen returned nil")
local out = f:read("*a")
f:close()
assert(out:find("popen_read_test"), "output did not contain expected string")
`
testString(t, s)
}

func TestIOPopenWrite(t *testing.T) {
s := `
local f = io.popen("cat", "w")
assert(f ~= nil, "io.popen returned nil")
f:write("popen_write_test\n")
f:close()
-- In write mode, read is not available, so just check that no error occurs
`
testString(t, s)
}
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