1 // Copyright 2020 Google LLC All Rights Reserved. 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); 4 // you may not use this file except in compliance with the License. 5 // You may obtain a copy of the License at 6 // 7 // http://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, 11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 // See the License for the specific language governing permissions and 13 // limitations under the License. 14 15 // Package editor implements a simple interface for interactive file editing. 16 // It most likely does not work on windows. 17 package editor 18 19 import ( 20 "fmt" 21 "io" 22 "os" 23 "os/exec" 24 "path/filepath" 25 ) 26 27 // Edit opens a temporary file in the default editor (per $EDITOR, falling back 28 // to "vi") with the contents of the given io.Reader and a filename ending in 29 // the given extension (to give a hint to the editor for syntax highlighting). 30 // 31 // The contents of the edited file are returned, and the temporary file removed. 32 func Edit(input io.Reader, extension string) ([]byte, error) { 33 f, err := os.CreateTemp("", fmt.Sprintf("%s-edit.*.%s", filepath.Base(os.Args[0]), extension)) 34 if err != nil { 35 return nil, err 36 } 37 defer os.Remove(f.Name()) 38 39 if _, err := io.Copy(f, input); err != nil { 40 return nil, err 41 } 42 f.Close() 43 44 editor := "vi" 45 if env := os.Getenv("EDITOR"); env != "" { 46 editor = env 47 } 48 49 path, err := exec.LookPath(editor) 50 if err != nil { 51 return nil, err 52 } 53 54 cmd := exec.Command(path, f.Name()) 55 cmd.Stdin = os.Stdin 56 cmd.Stdout = os.Stdout 57 cmd.Stderr = os.Stderr 58 59 if err := cmd.Run(); err != nil { 60 return nil, err 61 } 62 63 return os.ReadFile(f.Name()) 64 } 65