github.com/abdfnx/gh-api@v0.0.0-20210414084727-f5432eec23b8/pkg/surveyext/editor_manual.go (about)

     1  package surveyext
     2  
     3  import (
     4  	"bytes"
     5  	"io"
     6  	"io/ioutil"
     7  	"os"
     8  	"os/exec"
     9  
    10  	"github.com/cli/safeexec"
    11  	shellquote "github.com/kballard/go-shellquote"
    12  )
    13  
    14  type showable interface {
    15  	Show()
    16  }
    17  
    18  func Edit(editorCommand, fn, initialValue string, stdin io.Reader, stdout io.Writer, stderr io.Writer, cursor showable) (string, error) {
    19  	// prepare the temp file
    20  	pattern := fn
    21  	if pattern == "" {
    22  		pattern = "survey*.txt"
    23  	}
    24  	f, err := ioutil.TempFile("", pattern)
    25  	if err != nil {
    26  		return "", err
    27  	}
    28  	defer os.Remove(f.Name())
    29  
    30  	// write utf8 BOM header
    31  	// The reason why we do this is because notepad.exe on Windows determines the
    32  	// encoding of an "empty" text file by the locale, for example, GBK in China,
    33  	// while golang string only handles utf8 well. However, a text file with utf8
    34  	// BOM header is not considered "empty" on Windows, and the encoding will then
    35  	// be determined utf8 by notepad.exe, instead of GBK or other encodings.
    36  	if _, err := f.Write(bom); err != nil {
    37  		return "", err
    38  	}
    39  
    40  	// write initial value
    41  	if _, err := f.WriteString(initialValue); err != nil {
    42  		return "", err
    43  	}
    44  
    45  	// close the fd to prevent the editor unable to save file
    46  	if err := f.Close(); err != nil {
    47  		return "", err
    48  	}
    49  
    50  	if editorCommand == "" {
    51  		editorCommand = defaultEditor
    52  	}
    53  	args, err := shellquote.Split(editorCommand)
    54  	if err != nil {
    55  		return "", err
    56  	}
    57  	args = append(args, f.Name())
    58  
    59  	editorExe, err := safeexec.LookPath(args[0])
    60  	if err != nil {
    61  		return "", err
    62  	}
    63  
    64  	cmd := exec.Command(editorExe, args[1:]...)
    65  	cmd.Stdin = stdin
    66  	cmd.Stdout = stdout
    67  	cmd.Stderr = stderr
    68  
    69  	if cursor != nil {
    70  		cursor.Show()
    71  	}
    72  
    73  	// open the editor
    74  	if err := cmd.Run(); err != nil {
    75  		return "", err
    76  	}
    77  
    78  	// raw is a BOM-unstripped UTF8 byte slice
    79  	raw, err := ioutil.ReadFile(f.Name())
    80  	if err != nil {
    81  		return "", err
    82  	}
    83  
    84  	// strip BOM header
    85  	return string(bytes.TrimPrefix(raw, bom)), nil
    86  }