// Copyright 2009 The Go Authors. All rights reserved.

// Use of this source code is governed by a BSD-style

// license that can be found in the LICENSE file.

// Fork, exec, wait, etc.

package windows

// EscapeArg rewrites command line argument s as prescribed

// in http://msdn.microsoft.com/en-us/library/ms880421.

// This function returns "" (2 double quotes) if s is empty.

// Alternatively, these transformations are done:

// - every back slash (\) is doubled, but only if immediately

//   followed by double quote (");

// - every double quote (") is escaped by back slash (\);

// - finally, s is wrapped with double quotes (arg -> "arg"),

//   but only if there is space or tab inside s.

func EscapeArg(s string) string {

	if len(s) == 0 {

		return "\"\""

	}

	n := len(s)

	hasSpace := false

	for i := 0; i < len(s); i++ {

		switch s[i] {

		case '"', '\\':

			n++

		case ' ', '\t':

			hasSpace = true

		}

	}

	if hasSpace {

		n += 2

	}

	if n == len(s) {

		return s

	}

	qs := make([]byte, n)

	j := 0

	if hasSpace {

		qs[j] = '"'

		j++

	}

	slashes := 0

	for i := 0; i < len(s); i++ {

		switch s[i] {

		default:

			slashes = 0

			qs[j] = s[i]

		case '\\':

			slashes++

			qs[j] = s[i]

		case '"':

			for ; slashes > 0; slashes-- {

				qs[j] = '\\'

				j++

			}

			qs[j] = '\\'

			j++

			qs[j] = s[i]

		}

		j++

	}

	if hasSpace {

		for ; slashes > 0; slashes-- {

			qs[j] = '\\'

			j++

		}

		qs[j] = '"'

		j++

	}

	return string(qs[:j])

}

func CloseOnExec(fd Handle) {

	SetHandleInformation(Handle(fd), HANDLE_FLAG_INHERIT, 0)

}

// FullPath retrieves the full path of the specified file.

func FullPath(name string) (path string, err error) {

	p, err := UTF16PtrFromString(name)

	if err != nil {

		return "", err

	}

	n := uint32(100)

	for {

		buf := make([]uint16, n)

		n, err = GetFullPathName(p, uint32(len(buf)), &buf[0], nil)

		if err != nil {

			return "", err

		}

		if n <= uint32(len(buf)) {

			return UTF16ToString(buf[:n]), nil

		}

	}

}