github.com/oweisse/u-root@v0.0.0-20181109060735-d005ad25fef1/cmds/elvish/program/shell/script.go (about)

     1  package shell
     2  
     3  import (
     4  	"errors"
     5  	"fmt"
     6  	"io/ioutil"
     7  	"path/filepath"
     8  	"unicode/utf8"
     9  
    10  	"github.com/u-root/u-root/cmds/elvish/eval"
    11  	"github.com/u-root/u-root/cmds/elvish/parse"
    12  )
    13  
    14  // script evaluates a script. The returned error contains enough context and can
    15  // be printed as-is (with util.PprintError).
    16  func script(ev *eval.Evaler, args []string, cmd, compileOnly bool) error {
    17  	arg0 := args[0]
    18  	ev.SetArgs(args[1:])
    19  
    20  	var name, path, code string
    21  	if cmd {
    22  		name = "code from -c"
    23  		path = ""
    24  		code = arg0
    25  	} else {
    26  		var err error
    27  		name = arg0
    28  		path, err = filepath.Abs(name)
    29  		if err != nil {
    30  			return fmt.Errorf("cannot get full path of script %q: %v", name, err)
    31  		}
    32  		code, err = readFileUTF8(path)
    33  		if err != nil {
    34  			return fmt.Errorf("cannot read script %q: %v", name, err)
    35  		}
    36  	}
    37  
    38  	n, err := parse.Parse(name, code)
    39  	if err != nil {
    40  		return err
    41  	}
    42  
    43  	src := eval.NewScriptSource(name, path, code)
    44  	op, err := ev.Compile(n, src)
    45  	if err != nil {
    46  		return err
    47  	}
    48  	if compileOnly {
    49  		return nil
    50  	}
    51  
    52  	return ev.EvalWithStdPorts(op, src)
    53  }
    54  
    55  var errSourceNotUTF8 = errors.New("source is not UTF-8")
    56  
    57  func readFileUTF8(fname string) (string, error) {
    58  	bytes, err := ioutil.ReadFile(fname)
    59  	if err != nil {
    60  		return "", err
    61  	}
    62  	if !utf8.Valid(bytes) {
    63  		return "", errSourceNotUTF8
    64  	}
    65  	return string(bytes), nil
    66  }