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Diffstat (limited to 'src/pkg/path/path.go')
| -rw-r--r-- | src/pkg/path/path.go | 218 |
1 files changed, 0 insertions, 218 deletions
diff --git a/src/pkg/path/path.go b/src/pkg/path/path.go deleted file mode 100644 index bdb85c6b9..000000000 --- a/src/pkg/path/path.go +++ /dev/null @@ -1,218 +0,0 @@ -// 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 path implements utility routines for manipulating slash-separated -// paths. -package path - -import ( - "strings" -) - -// A lazybuf is a lazily constructed path buffer. -// It supports append, reading previously appended bytes, -// and retrieving the final string. It does not allocate a buffer -// to hold the output until that output diverges from s. -type lazybuf struct { - s string - buf []byte - w int -} - -func (b *lazybuf) index(i int) byte { - if b.buf != nil { - return b.buf[i] - } - return b.s[i] -} - -func (b *lazybuf) append(c byte) { - if b.buf == nil { - if b.w < len(b.s) && b.s[b.w] == c { - b.w++ - return - } - b.buf = make([]byte, len(b.s)) - copy(b.buf, b.s[:b.w]) - } - b.buf[b.w] = c - b.w++ -} - -func (b *lazybuf) string() string { - if b.buf == nil { - return b.s[:b.w] - } - return string(b.buf[:b.w]) -} - -// Clean returns the shortest path name equivalent to path -// by purely lexical processing. It applies the following rules -// iteratively until no further processing can be done: -// -// 1. Replace multiple slashes with a single slash. -// 2. Eliminate each . path name element (the current directory). -// 3. Eliminate each inner .. path name element (the parent directory) -// along with the non-.. element that precedes it. -// 4. Eliminate .. elements that begin a rooted path: -// that is, replace "/.." by "/" at the beginning of a path. -// -// The returned path ends in a slash only if it is the root "/". -// -// If the result of this process is an empty string, Clean -// returns the string ".". -// -// See also Rob Pike, ``Lexical File Names in Plan 9 or -// Getting Dot-Dot Right,'' -// http://plan9.bell-labs.com/sys/doc/lexnames.html -func Clean(path string) string { - if path == "" { - return "." - } - - rooted := path[0] == '/' - n := len(path) - - // Invariants: - // reading from path; r is index of next byte to process. - // writing to buf; w is index of next byte to write. - // dotdot is index in buf where .. must stop, either because - // it is the leading slash or it is a leading ../../.. prefix. - out := lazybuf{s: path} - r, dotdot := 0, 0 - if rooted { - out.append('/') - r, dotdot = 1, 1 - } - - for r < n { - switch { - case path[r] == '/': - // empty path element - r++ - case path[r] == '.' && (r+1 == n || path[r+1] == '/'): - // . element - r++ - case path[r] == '.' && path[r+1] == '.' && (r+2 == n || path[r+2] == '/'): - // .. element: remove to last / - r += 2 - switch { - case out.w > dotdot: - // can backtrack - out.w-- - for out.w > dotdot && out.index(out.w) != '/' { - out.w-- - } - case !rooted: - // cannot backtrack, but not rooted, so append .. element. - if out.w > 0 { - out.append('/') - } - out.append('.') - out.append('.') - dotdot = out.w - } - default: - // real path element. - // add slash if needed - if rooted && out.w != 1 || !rooted && out.w != 0 { - out.append('/') - } - // copy element - for ; r < n && path[r] != '/'; r++ { - out.append(path[r]) - } - } - } - - // Turn empty string into "." - if out.w == 0 { - return "." - } - - return out.string() -} - -// Split splits path immediately following the final slash. -// separating it into a directory and file name component. -// If there is no slash path, Split returns an empty dir and -// file set to path. -// The returned values have the property that path = dir+file. -func Split(path string) (dir, file string) { - i := strings.LastIndex(path, "/") - return path[:i+1], path[i+1:] -} - -// Join joins any number of path elements into a single path, adding a -// separating slash if necessary. The result is Cleaned; in particular, -// all empty strings are ignored. -func Join(elem ...string) string { - for i, e := range elem { - if e != "" { - return Clean(strings.Join(elem[i:], "/")) - } - } - return "" -} - -// Ext returns the file name extension used by path. -// The extension is the suffix beginning at the final dot -// in the final slash-separated element of path; -// it is empty if there is no dot. -func Ext(path string) string { - for i := len(path) - 1; i >= 0 && path[i] != '/'; i-- { - if path[i] == '.' { - return path[i:] - } - } - return "" -} - -// Base returns the last element of path. -// Trailing slashes are removed before extracting the last element. -// If the path is empty, Base returns ".". -// If the path consists entirely of slashes, Base returns "/". -func Base(path string) string { - if path == "" { - return "." - } - // Strip trailing slashes. - for len(path) > 0 && path[len(path)-1] == '/' { - path = path[0 : len(path)-1] - } - // Find the last element - if i := strings.LastIndex(path, "/"); i >= 0 { - path = path[i+1:] - } - // If empty now, it had only slashes. - if path == "" { - return "/" - } - return path -} - -// IsAbs returns true if the path is absolute. -func IsAbs(path string) bool { - return len(path) > 0 && path[0] == '/' -} - -// Dir returns all but the last element of path, typically the path's directory. -// After dropping the final element using Split, the path is Cleaned and trailing -// slashes are removed. -// If the path is empty, Dir returns ".". -// If the path consists entirely of slashes followed by non-slash bytes, Dir -// returns a single slash. In any other case, the returned path does not end in a -// slash. -func Dir(path string) string { - dir, _ := Split(path) - dir = Clean(dir) - last := len(dir) - 1 - if last > 0 && dir[last] == '/' { - dir = dir[:last] - } - if dir == "" { - dir = "." - } - return dir -} |
