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Parse Windows commands differently than Unix commands

Stinkin' backslashes
This commit is contained in:
Matthew Holt 2015-10-21 14:03:33 -06:00
parent 136119f8ac
commit 29362e45bc
2 changed files with 144 additions and 5 deletions

View file

@ -2,6 +2,9 @@ package middleware
import (
"errors"
"runtime"
"strings"
"unicode"
"github.com/flynn/go-shlex"
)
@ -9,11 +12,19 @@ import (
// SplitCommandAndArgs takes a command string and parses it
// shell-style into the command and its separate arguments.
func SplitCommandAndArgs(command string) (cmd string, args []string, err error) {
parts, err := shlex.Split(command)
if err != nil {
err = errors.New("error parsing command: " + err.Error())
return
} else if len(parts) == 0 {
var parts []string
if runtime.GOOS == "windows" {
parts = parseWindowsCommand(command) // parse it Windows-style
} else {
parts, err = shlex.Split(command) // parse it Unix-style
if err != nil {
err = errors.New("error parsing command: " + err.Error())
return
}
}
if len(parts) == 0 {
err = errors.New("no command contained in '" + command + "'")
return
}
@ -25,3 +36,64 @@ func SplitCommandAndArgs(command string) (cmd string, args []string, err error)
return
}
// parseWindowsCommand is a sad but good-enough attempt to
// split a command into the command and its arguments like
// the Windows command line would; only basic parsing is
// supported. This function has to be used on Windows instead
// of the shlex package because this function treats backslash
// characters properly.
//
// Loosely based off the rules here: http://stackoverflow.com/a/4094897/1048862
// True parsing is much, much trickier.
func parseWindowsCommand(cmd string) []string {
var parts []string
var part string
var quoted bool
var backslashes int
for _, ch := range cmd {
if ch == '\\' {
backslashes++
continue
}
var evenBacksl = (backslashes % 2) == 0
if backslashes > 0 && ch != '\\' {
numBacksl := (backslashes / 2) + 1
if ch == '"' {
numBacksl--
}
part += strings.Repeat(`\`, numBacksl)
backslashes = 0
}
if quoted {
if ch == '"' && evenBacksl {
quoted = false
continue
}
part += string(ch)
continue
}
if unicode.IsSpace(ch) && len(part) > 0 {
parts = append(parts, part)
part = ""
continue
}
if ch == '"' && evenBacksl {
quoted = true
continue
}
part += string(ch)
}
if len(part) > 0 {
parts = append(parts, part)
part = ""
}
return parts
}

View file

@ -6,6 +6,73 @@ import (
"testing"
)
func TestParseWindowsCommand(t *testing.T) {
for i, test := range []struct {
input string
expected []string
}{
{ // 0
input: `cmd`,
expected: []string{`cmd`},
},
{ // 1
input: `cmd arg1 arg2`,
expected: []string{`cmd`, `arg1`, `arg2`},
},
{ // 2
input: `cmd "combined arg" arg2`,
expected: []string{`cmd`, `combined arg`, `arg2`},
},
{ // 3
input: `mkdir C:\Windows\foo\bar`,
expected: []string{`mkdir`, `C:\Windows\foo\bar`},
},
{ // 4
input: `"command here"`,
expected: []string{`command here`},
},
{ // 5
input: `cmd \"arg\"`,
expected: []string{`cmd`, `"arg"`},
},
{ // 6
input: `cmd "a \"quoted value\""`,
expected: []string{`cmd`, `a "quoted value"`},
},
{ // 7
input: `mkdir "C:\directory name\foobar"`,
expected: []string{`mkdir`, `C:\directory name\foobar`},
},
{ // 8
input: `mkdir C:\ space`,
expected: []string{`mkdir`, `C:\`, `space`},
},
{ // 9
input: `mkdir "C:\ space"`,
expected: []string{`mkdir`, `C:\ space`},
},
{ // 10
input: `\\"`,
expected: []string{`\`},
},
{ // 11
input: `"\\\""`,
expected: []string{`\"`},
},
} {
actual := parseWindowsCommand(test.input)
if len(actual) != len(test.expected) {
t.Errorf("Test %d: Expected %d parts, got %d: %#v", i, len(test.expected), len(actual), actual)
continue
}
for j := 0; j < len(actual); j++ {
if expectedPart, actualPart := test.expected[j], actual[j]; expectedPart != actualPart {
t.Errorf("Test %d: Expected: %v Actual: %v (index %d)", i, expectedPart, actualPart, j)
}
}
}
}
func TestSplitCommandAndArgs(t *testing.T) {
var parseErrorContent = "error parsing command:"
var noCommandErrContent = "no command contained in"