File size: 3,864 Bytes
d7a5f2f | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 | // 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.
package objabi
import (
"internal/buildcfg"
"os"
"path/filepath"
"runtime"
"strings"
)
// WorkingDir returns the current working directory
// (or "/???" if the directory cannot be identified),
// with "/" as separator.
func WorkingDir() string {
var path string
path, _ = os.Getwd()
if path == "" {
path = "/???"
}
return filepath.ToSlash(path)
}
// AbsFile returns the absolute filename for file in the given directory,
// as rewritten by the rewrites argument.
// For unrewritten paths, AbsFile rewrites a leading $GOROOT prefix to the literal "$GOROOT".
// If the resulting path is the empty string, the result is "??".
//
// The rewrites argument is a ;-separated list of rewrites.
// Each rewrite is of the form "prefix" or "prefix=>replace",
// where prefix must match a leading sequence of path elements
// and is either removed entirely or replaced by the replacement.
func AbsFile(dir, file, rewrites string) string {
abs := file
if dir != "" && !filepath.IsAbs(file) {
abs = filepath.Join(dir, file)
}
abs, rewritten := ApplyRewrites(abs, rewrites)
if !rewritten && buildcfg.GOROOT != "" && hasPathPrefix(abs, buildcfg.GOROOT) {
abs = "$GOROOT" + abs[len(buildcfg.GOROOT):]
}
// Rewrite paths to match the slash convention of the target.
// This helps ensure that cross-compiled distributions remain
// bit-for-bit identical to natively compiled distributions.
if runtime.GOOS == "windows" {
abs = strings.ReplaceAll(abs, `\`, "/")
}
if abs == "" {
abs = "??"
}
return abs
}
// ApplyRewrites returns the filename for file in the given directory,
// as rewritten by the rewrites argument.
//
// The rewrites argument is a ;-separated list of rewrites.
// Each rewrite is of the form "prefix" or "prefix=>replace",
// where prefix must match a leading sequence of path elements
// and is either removed entirely or replaced by the replacement.
func ApplyRewrites(file, rewrites string) (string, bool) {
start := 0
for i := 0; i <= len(rewrites); i++ {
if i == len(rewrites) || rewrites[i] == ';' {
if new, ok := applyRewrite(file, rewrites[start:i]); ok {
return new, true
}
start = i + 1
}
}
return file, false
}
// applyRewrite applies the rewrite to the path,
// returning the rewritten path and a boolean
// indicating whether the rewrite applied at all.
func applyRewrite(path, rewrite string) (string, bool) {
prefix, replace := rewrite, ""
if j := strings.LastIndex(rewrite, "=>"); j >= 0 {
prefix, replace = rewrite[:j], rewrite[j+len("=>"):]
}
if prefix == "" || !hasPathPrefix(path, prefix) {
return path, false
}
if len(path) == len(prefix) {
return replace, true
}
if replace == "" {
return path[len(prefix)+1:], true
}
return replace + path[len(prefix):], true
}
// Does s have t as a path prefix?
// That is, does s == t or does s begin with t followed by a slash?
// For portability, we allow ASCII case folding, so that hasPathPrefix("a/b/c", "A/B") is true.
// Similarly, we allow slash folding, so that hasPathPrefix("a/b/c", "a\\b") is true.
// We do not allow full Unicode case folding, for fear of causing more confusion
// or harm than good. (For an example of the kinds of things that can go wrong,
// see http://article.gmane.org/gmane.linux.kernel/1853266.)
func hasPathPrefix(s string, t string) bool {
if len(t) > len(s) {
return false
}
var i int
for i = 0; i < len(t); i++ {
cs := int(s[i])
ct := int(t[i])
if 'A' <= cs && cs <= 'Z' {
cs += 'a' - 'A'
}
if 'A' <= ct && ct <= 'Z' {
ct += 'a' - 'A'
}
if cs == '\\' {
cs = '/'
}
if ct == '\\' {
ct = '/'
}
if cs != ct {
return false
}
}
return i >= len(s) || s[i] == '/' || s[i] == '\\'
}
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