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// Copyright 2017 Google Inc. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package terminal
import (
"bytes"
"io"
"os"
"syscall"
"unsafe"
)
func isTerminal(w io.Writer) bool {
if f, ok := w.(*os.File); ok {
var termios syscall.Termios
_, _, err := syscall.Syscall6(syscall.SYS_IOCTL, f.Fd(),
ioctlGetTermios, uintptr(unsafe.Pointer(&termios)),
0, 0, 0)
return err == 0
} else if _, ok := w.(*fakeSmartTerminal); ok {
return true
}
return false
}
func termWidth(w io.Writer) (int, bool) {
if f, ok := w.(*os.File); ok {
var winsize struct {
ws_row, ws_column uint16
ws_xpixel, ws_ypixel uint16
}
_, _, err := syscall.Syscall6(syscall.SYS_IOCTL, f.Fd(),
syscall.TIOCGWINSZ, uintptr(unsafe.Pointer(&winsize)),
0, 0, 0)
return int(winsize.ws_column), err == 0
} else if f, ok := w.(*fakeSmartTerminal); ok {
return f.termWidth, true
}
return 0, false
}
// stripAnsiEscapes strips ANSI control codes from a byte array in place.
func stripAnsiEscapes(input []byte) []byte {
// read represents the remaining part of input that needs to be processed.
read := input
// write represents where we should be writing in input.
// It will share the same backing store as input so that we make our modifications
// in place.
write := input
// advance will copy count bytes from read to write and advance those slices
advance := func(write, read []byte, count int) ([]byte, []byte) {
copy(write, read[:count])
return write[count:], read[count:]
}
for {
// Find the next escape sequence
i := bytes.IndexByte(read, 0x1b)
// If it isn't found, or if there isn't room for <ESC>[, finish
if i == -1 || i+1 >= len(read) {
copy(write, read)
break
}
// Not a CSI code, continue searching
if read[i+1] != '[' {
write, read = advance(write, read, i+1)
continue
}
// Found a CSI code, advance up to the <ESC>
write, read = advance(write, read, i)
// Find the end of the CSI code
i = bytes.IndexFunc(read, func(r rune) bool {
return (r >= 'a' && r <= 'z') || (r >= 'A' && r <= 'Z')
})
if i == -1 {
// We didn't find the end of the code, just remove the rest
i = len(read) - 1
}
// Strip off the end marker too
i = i + 1
// Skip the reader forward and reduce final length by that amount
read = read[i:]
input = input[:len(input)-i]
}
return input
}
type fakeSmartTerminal struct {
bytes.Buffer
termWidth int
}
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