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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 isSmartTerminal(w io.Writer) bool {
- if f, ok := w.(*os.File); ok {
- if term, ok := os.LookupEnv("TERM"); ok && term == "dumb" {
- return false
- }
- 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 termSize(w io.Writer) (width int, height int, ok bool) {
- if f, ok := w.(*os.File); ok {
- var winsize struct {
- wsRow, wsColumn uint16
- wsXpixel, wsYpixel uint16
- }
- _, _, err := syscall.Syscall6(syscall.SYS_IOCTL, f.Fd(),
- syscall.TIOCGWINSZ, uintptr(unsafe.Pointer(&winsize)),
- 0, 0, 0)
- return int(winsize.wsColumn), int(winsize.wsRow), err == 0
- } else if f, ok := w.(*fakeSmartTerminal); ok {
- return f.termWidth, f.termHeight, true
- }
- return 0, 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, termHeight int
- }
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