github.com/goproxy0/go@v0.0.0-20171111080102-49cc0c489d2c/src/cmd/internal/objabi/line.go (about)

     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  package objabi
     6  
     7  import (
     8  	"os"
     9  	"path/filepath"
    10  )
    11  
    12  // WorkingDir returns the current working directory
    13  // (or "/???" if the directory cannot be identified),
    14  // with "/" as separator.
    15  func WorkingDir() string {
    16  	var path string
    17  	path, _ = os.Getwd()
    18  	if path == "" {
    19  		path = "/???"
    20  	}
    21  	return filepath.ToSlash(path)
    22  }
    23  
    24  // AbsFile returns the absolute filename for file in the given directory.
    25  // It also removes a leading pathPrefix, or else rewrites a leading $GOROOT
    26  // prefix to the literal "$GOROOT".
    27  // If the resulting path is the empty string, the result is "??".
    28  func AbsFile(dir, file, pathPrefix string) string {
    29  	abs := file
    30  	if dir != "" && !filepath.IsAbs(file) {
    31  		abs = filepath.Join(dir, file)
    32  	}
    33  
    34  	if pathPrefix != "" && hasPathPrefix(abs, pathPrefix) {
    35  		if abs == pathPrefix {
    36  			abs = ""
    37  		} else {
    38  			abs = abs[len(pathPrefix)+1:]
    39  		}
    40  	} else if hasPathPrefix(abs, GOROOT) {
    41  		abs = "$GOROOT" + abs[len(GOROOT):]
    42  	}
    43  	if abs == "" {
    44  		abs = "??"
    45  	}
    46  
    47  	return abs
    48  }
    49  
    50  // Does s have t as a path prefix?
    51  // That is, does s == t or does s begin with t followed by a slash?
    52  // For portability, we allow ASCII case folding, so that hasPathPrefix("a/b/c", "A/B") is true.
    53  // Similarly, we allow slash folding, so that hasPathPrefix("a/b/c", "a\\b") is true.
    54  // We do not allow full Unicode case folding, for fear of causing more confusion
    55  // or harm than good. (For an example of the kinds of things that can go wrong,
    56  // see http://article.gmane.org/gmane.linux.kernel/1853266.)
    57  func hasPathPrefix(s string, t string) bool {
    58  	if len(t) > len(s) {
    59  		return false
    60  	}
    61  	var i int
    62  	for i = 0; i < len(t); i++ {
    63  		cs := int(s[i])
    64  		ct := int(t[i])
    65  		if 'A' <= cs && cs <= 'Z' {
    66  			cs += 'a' - 'A'
    67  		}
    68  		if 'A' <= ct && ct <= 'Z' {
    69  			ct += 'a' - 'A'
    70  		}
    71  		if cs == '\\' {
    72  			cs = '/'
    73  		}
    74  		if ct == '\\' {
    75  			ct = '/'
    76  		}
    77  		if cs != ct {
    78  			return false
    79  		}
    80  	}
    81  	return i >= len(s) || s[i] == '/' || s[i] == '\\'
    82  }