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