github.com/u-root/u-root@v7.0.1-0.20200915234505-ad7babab0a8e+incompatible/pkg/complete/env.go (about)

     1  // Copyright 2012-2018 the u-root Authors. All rights reserved
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package complete
     6  
     7  import (
     8  	"fmt"
     9  	"os"
    10  	"strings"
    11  )
    12  
    13  // NewEnvCompleter creates a MultiCompleter consisting of one
    14  // or more FileCompleters. It is given an environment variable,
    15  // which it splits on :. If there are only zero entries,
    16  // it returns an error; else it returns a MultiCompleter.
    17  // N.B. it does *not* check for whether a directory exists
    18  // or not; directories can come and go.
    19  func NewEnvCompleter(s string) (Completer, error) {
    20  	e := os.Getenv(s)
    21  	Debug("NewEnvCompleter: path %q has value %q", s, e)
    22  	if e == "" {
    23  		return nil, ErrEmptyEnv
    24  	}
    25  	dirs := strings.Split(e, ":")
    26  	if len(dirs) == 0 {
    27  		return nil, fmt.Errorf("%s is empty", s)
    28  	}
    29  	Debug("Build completer for %d dirs: %v", len(dirs), dirs)
    30  	c := make([]Completer, len(dirs))
    31  	for i := range dirs {
    32  		c[i] = NewFileCompleter(dirs[i])
    33  	}
    34  	return NewMultiCompleter(c[0], c[1:]...), nil
    35  }
    36  
    37  // NewPathCompleter calls NewEnvCompleter with "PATH" as the
    38  // variable name. It can be used to create completers for shells.
    39  func NewPathCompleter() (Completer, error) {
    40  	// Getenv returns the same value ("") if a path is not found
    41  	// or if it has the value "". Oh well.
    42  	return NewEnvCompleter("PATH")
    43  }