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https://github.com/sorenisanerd/gotty.git
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Replace UTF8 bounds check with utf8reader
This commit is contained in:
parent
d0f2128996
commit
87f8409068
4
Godeps/Godeps.json
generated
4
Godeps/Godeps.json
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@ -19,6 +19,10 @@
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"ImportPath": "github.com/kr/pty",
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"Comment": "release.r56-28-g5cf931e",
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"Rev": "5cf931ef8f76dccd0910001d74a58a7fca84a83d"
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},
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{
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"ImportPath": "github.com/yudai/utf8reader",
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"Rev": "543610cf49fc1279921d6ef1b7f7773ebece14f8"
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}
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]
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}
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65
Godeps/_workspace/src/github.com/yudai/utf8reader/README.md
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vendored
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65
Godeps/_workspace/src/github.com/yudai/utf8reader/README.md
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@ -0,0 +1,65 @@
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# UTF8Reader for Go
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UTF8Reader is a simple wrapper Reader that fills the given buffer with a "tail-safe" UTF8 byte sequence.
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## Tail-Safe?
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Let's say you have a buffer of 7 bytes and your Reader is going to fill your buffer with a UTF8 byte sequence.
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```go
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buf := make([]byte, 7)
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reader := strings.NewReader("いろは")
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reader.Read(buf)
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```
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The byte length of UTF8 characters is not fixed and some characters like the examples above have 3 byte length. There are others which have a single byte, 2 byte and 4 byte length as well. This means your buffer will be sometimes filled with incomplete bytes as an Unicode character at the tail.
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By `reader.Read(buf)`, your `buf` will be like below:
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```go
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[]byte{
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// い
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byte(0xe3), // 1
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byte(0x81), // 2
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byte(0x84), // 3
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// ろ
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byte(0xe3), // 4
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byte(0x82), // 5
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byte(0x8d), // 6
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// は (incomplete)
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byte(0xe3), // 7
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}
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```
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The last character `は` is incomplete and the buffer is now invalid as a UTF8 string.
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UTF8Reader detects incomplete bytes like above and aborts filling up the buffer in such cases.
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```go
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buf := make([]byte, 7)
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reader := strings.NewReader("いろは")
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utfReader := utf8reader.New(reader)
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utfReader.Read(buf)
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```
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Then you will get:
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```go
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[]byte{
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// い
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byte(0xe3), // 1
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byte(0x81), // 2
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byte(0x84), // 3
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// ろ
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byte(0xe3), // 4
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byte(0x82), // 5
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byte(0x8d), // 6
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}
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```
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Of course, bytes left behind will be used to fill up the buffer on next `Read()`.
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## Note
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UTF8Reader just checks incomplete bytes at the tail of the buffer. Even if the original byte sequence given to UTF8Reader is broken, UTF8Reader reports no errors and just fills up the buffer.
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56
Godeps/_workspace/src/github.com/yudai/utf8reader/utf8reader.go
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56
Godeps/_workspace/src/github.com/yudai/utf8reader/utf8reader.go
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@ -0,0 +1,56 @@
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package utf8reader
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import (
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"bytes"
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"errors"
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"io"
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"unicode/utf8"
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)
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var SmallBufferError = errors.New("Buffer size must be larger than utf8.UTFMax.")
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type UTF8Reader struct {
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reader io.Reader
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buffer *bytes.Buffer
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}
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func New(reader io.Reader) *UTF8Reader {
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return &UTF8Reader{
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reader: reader,
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buffer: bytes.NewBuffer(make([]byte, 0)),
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}
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}
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func (r *UTF8Reader) Read(p []byte) (n int, err error) {
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size := 0
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if cap(p) < utf8.UTFMax {
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return size, SmallBufferError
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}
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if r.buffer.Len() > 0 {
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n, err = r.buffer.Read(p)
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size += n
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if err != nil {
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return size, err
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}
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}
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n, err = r.reader.Read(p[size:])
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size += n
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if err != nil {
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return size, err
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}
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leftOver := 0
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for ; leftOver < utf8.UTFMax; leftOver++ {
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rune, _ := utf8.DecodeLastRune(p[:size-leftOver])
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if rune != utf8.RuneError {
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break
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}
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}
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r.buffer.Write(p[size-leftOver : size])
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return size - leftOver, nil
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}
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79
Godeps/_workspace/src/github.com/yudai/utf8reader/utf8reader_test.go
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79
Godeps/_workspace/src/github.com/yudai/utf8reader/utf8reader_test.go
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@ -0,0 +1,79 @@
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package utf8reader
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import (
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"testing"
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"bytes"
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"strings"
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)
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func TestRead(t *testing.T) {
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str := "日本語"
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or := strings.NewReader(str)
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r := New(or)
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buf := make([]byte, 512)
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n, err := r.Read(buf)
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if err != nil {
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t.Errorf("Unexpected error")
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}
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if bytes.Compare(buf[:n], []byte(str)) != 0 {
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t.Errorf("Failed to read bytes")
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}
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n, err = r.Read(buf)
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if err.Error() != "EOF" {
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t.Errorf("Unexpected error")
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}
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// 3 byte runes
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str = "いろはにほ"
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or = strings.NewReader(str)
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r = New(or)
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buf = make([]byte, 7) // 7 % 3 = 1
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n, err = r.Read(buf)
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if err != nil {
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t.Errorf("Unexpected error")
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}
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if n != 6 {
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t.Errorf("Read length error")
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}
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if bytes.Compare(buf[:n], []byte(str)[:6]) != 0 {
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t.Errorf("Failed to read bytes")
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}
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n, err = r.Read(buf)
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if err != nil {
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t.Errorf("Unexpected error")
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}
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if n != 6 {
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t.Errorf("Read length error")
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}
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if bytes.Compare(buf[:n], []byte(str)[6:12]) != 0 {
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t.Errorf("Failed to read bytes")
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}
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n, err = r.Read(buf)
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if err != nil {
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t.Errorf("Unexpected error")
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}
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if n != 3 {
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t.Errorf("Read length error")
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}
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if bytes.Compare(buf[:n], []byte(str)[12:15]) != 0 {
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t.Errorf("Failed to read bytes")
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}
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}
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func TestReadWithSmallBuffer(t *testing.T) {
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str := "日本語"
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or := strings.NewReader(str)
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r := New(or)
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buf := make([]byte, 2) // too small
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_, err := r.Read(buf)
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if err != SmallBufferError {
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t.Errorf("Expected error were not returned")
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}
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}
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34
app/app.go
34
app/app.go
@ -7,12 +7,12 @@ import (
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"os/exec"
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"strings"
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"syscall"
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"unicode/utf8"
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"unsafe"
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"github.com/elazarl/go-bindata-assetfs"
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"github.com/gorilla/websocket"
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"github.com/kr/pty"
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"github.com/yudai/utf8reader"
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)
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type App struct {
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@ -83,11 +83,10 @@ func (app *App) generateHandler() func(w http.ResponseWriter, r *http.Request) {
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defer func() { exit <- true }()
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buf := make([]byte, 1024)
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leftOver := 0
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for {
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size, err := fio.Read(buf[leftOver:])
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size += leftOver
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utf8f := utf8reader.New(fio)
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for {
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size, err := utf8f.Read(buf)
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if err != nil {
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log.Printf("command exited for: %s", r.RemoteAddr)
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return
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@ -98,31 +97,8 @@ func (app *App) generateHandler() func(w http.ResponseWriter, r *http.Request) {
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return
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}
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// UTF-8 Boundary check
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for leftOver = 0; leftOver < utf8.UTFMax; leftOver++ {
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re, _ := utf8.DecodeLastRune(
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buf[:size-leftOver],
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)
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if re != utf8.RuneError {
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break
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}
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// Invalid UTF rune
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}
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if leftOver == utf8.UTFMax-1 {
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re, _ := utf8.DecodeLastRune(buf[:size-leftOver])
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if re == utf8.RuneError {
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log.Fatal("UTF8 Boundary error.")
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}
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}
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writer.Write(buf[:size-leftOver])
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writer.Write(buf[:size])
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writer.Close()
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for i := 0; i < leftOver; i++ {
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buf[i] = buf[size-leftOver+i]
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}
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}
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}()
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