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// 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 (
"os"
"path/filepath"
"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 && hasPathPrefix(abs, GOROOT) {
abs = "$GOROOT" + abs[len(GOROOT):]
}
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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