github.com/cli/cli@v1.14.1-0.20210902173923-1af6a669e342/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  	return edit(editorCommand, fn, initialValue, stdin, stdout, stderr, cursor, defaultLookPath)
    20  }
    21  
    22  func defaultLookPath(name string) ([]string, []string, error) {
    23  	exe, err := safeexec.LookPath(name)
    24  	if err != nil {
    25  		return nil, nil, err
    26  	}
    27  	return []string{exe}, nil, nil
    28  }
    29  
    30  func edit(editorCommand, fn, initialValue string, stdin io.Reader, stdout io.Writer, stderr io.Writer, cursor showable, lookPath func(string) ([]string, []string, error)) (string, error) {
    31  	// prepare the temp file
    32  	pattern := fn
    33  	if pattern == "" {
    34  		pattern = "survey*.txt"
    35  	}
    36  	f, err := ioutil.TempFile("", pattern)
    37  	if err != nil {
    38  		return "", err
    39  	}
    40  	defer os.Remove(f.Name())
    41  
    42  	// write utf8 BOM header
    43  	// The reason why we do this is because notepad.exe on Windows determines the
    44  	// encoding of an "empty" text file by the locale, for example, GBK in China,
    45  	// while golang string only handles utf8 well. However, a text file with utf8
    46  	// BOM header is not considered "empty" on Windows, and the encoding will then
    47  	// be determined utf8 by notepad.exe, instead of GBK or other encodings.
    48  	if _, err := f.Write(bom); err != nil {
    49  		return "", err
    50  	}
    51  
    52  	// write initial value
    53  	if _, err := f.WriteString(initialValue); err != nil {
    54  		return "", err
    55  	}
    56  
    57  	// close the fd to prevent the editor unable to save file
    58  	if err := f.Close(); err != nil {
    59  		return "", err
    60  	}
    61  
    62  	if editorCommand == "" {
    63  		editorCommand = defaultEditor
    64  	}
    65  	args, err := shellquote.Split(editorCommand)
    66  	if err != nil {
    67  		return "", err
    68  	}
    69  	args = append(args, f.Name())
    70  
    71  	editorExe, env, err := lookPath(args[0])
    72  	if err != nil {
    73  		return "", err
    74  	}
    75  	args = append(editorExe, args[1:]...)
    76  
    77  	cmd := exec.Command(args[0], args[1:]...)
    78  	cmd.Env = env
    79  	cmd.Stdin = stdin
    80  	cmd.Stdout = stdout
    81  	cmd.Stderr = stderr
    82  
    83  	if cursor != nil {
    84  		cursor.Show()
    85  	}
    86  
    87  	// open the editor
    88  	if err := cmd.Run(); err != nil {
    89  		return "", err
    90  	}
    91  
    92  	// raw is a BOM-unstripped UTF8 byte slice
    93  	raw, err := ioutil.ReadFile(f.Name())
    94  	if err != nil {
    95  		return "", err
    96  	}
    97  
    98  	// strip BOM header
    99  	return string(bytes.TrimPrefix(raw, bom)), nil
   100  }