1// Copyright 2009 The Go 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// Fork, exec, wait, etc.
6
7package windows
8
9import (
10	errorspkg "errors"
11	"unsafe"
12)
13
14// EscapeArg rewrites command line argument s as prescribed
15// in http://msdn.microsoft.com/en-us/library/ms880421.
16// This function returns "" (2 double quotes) if s is empty.
17// Alternatively, these transformations are done:
18// - every back slash (\) is doubled, but only if immediately
19//   followed by double quote (");
20// - every double quote (") is escaped by back slash (\);
21// - finally, s is wrapped with double quotes (arg -> "arg"),
22//   but only if there is space or tab inside s.
23func EscapeArg(s string) string {
24	if len(s) == 0 {
25		return "\"\""
26	}
27	n := len(s)
28	hasSpace := false
29	for i := 0; i < len(s); i++ {
30		switch s[i] {
31		case '"', '\\':
32			n++
33		case ' ', '\t':
34			hasSpace = true
35		}
36	}
37	if hasSpace {
38		n += 2
39	}
40	if n == len(s) {
41		return s
42	}
43
44	qs := make([]byte, n)
45	j := 0
46	if hasSpace {
47		qs[j] = '"'
48		j++
49	}
50	slashes := 0
51	for i := 0; i < len(s); i++ {
52		switch s[i] {
53		default:
54			slashes = 0
55			qs[j] = s[i]
56		case '\\':
57			slashes++
58			qs[j] = s[i]
59		case '"':
60			for ; slashes > 0; slashes-- {
61				qs[j] = '\\'
62				j++
63			}
64			qs[j] = '\\'
65			j++
66			qs[j] = s[i]
67		}
68		j++
69	}
70	if hasSpace {
71		for ; slashes > 0; slashes-- {
72			qs[j] = '\\'
73			j++
74		}
75		qs[j] = '"'
76		j++
77	}
78	return string(qs[:j])
79}
80
81func CloseOnExec(fd Handle) {
82	SetHandleInformation(Handle(fd), HANDLE_FLAG_INHERIT, 0)
83}
84
85// FullPath retrieves the full path of the specified file.
86func FullPath(name string) (path string, err error) {
87	p, err := UTF16PtrFromString(name)
88	if err != nil {
89		return "", err
90	}
91	n := uint32(100)
92	for {
93		buf := make([]uint16, n)
94		n, err = GetFullPathName(p, uint32(len(buf)), &buf[0], nil)
95		if err != nil {
96			return "", err
97		}
98		if n <= uint32(len(buf)) {
99			return UTF16ToString(buf[:n]), nil
100		}
101	}
102}
103
104// NewProcThreadAttributeList allocates a new ProcThreadAttributeList, with the requested maximum number of attributes.
105func NewProcThreadAttributeList(maxAttrCount uint32) (*ProcThreadAttributeList, error) {
106	var size uintptr
107	err := initializeProcThreadAttributeList(nil, maxAttrCount, 0, &size)
108	if err != ERROR_INSUFFICIENT_BUFFER {
109		if err == nil {
110			return nil, errorspkg.New("unable to query buffer size from InitializeProcThreadAttributeList")
111		}
112		return nil, err
113	}
114	const psize = unsafe.Sizeof(uintptr(0))
115	// size is guaranteed to be ≥1 by InitializeProcThreadAttributeList.
116	al := (*ProcThreadAttributeList)(unsafe.Pointer(&make([]unsafe.Pointer, (size+psize-1)/psize)[0]))
117	err = initializeProcThreadAttributeList(al, maxAttrCount, 0, &size)
118	if err != nil {
119		return nil, err
120	}
121	return al, err
122}
123
124// Update modifies the ProcThreadAttributeList using UpdateProcThreadAttribute.
125func (al *ProcThreadAttributeList) Update(attribute uintptr, flags uint32, value unsafe.Pointer, size uintptr, prevValue unsafe.Pointer, returnedSize *uintptr) error {
126	return updateProcThreadAttribute(al, flags, attribute, value, size, prevValue, returnedSize)
127}
128
129// Delete frees ProcThreadAttributeList's resources.
130func (al *ProcThreadAttributeList) Delete() {
131	deleteProcThreadAttributeList(al)
132}
133