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;;;; pathname parsing for Unix filesystems
;;;; This software is part of the SBCL system. See the README file for
;;;; more information.
;;;;
;;;; This software is derived from the CMU CL system, which was
;;;; written at Carnegie Mellon University and released into the
;;;; public domain. The software is in the public domain and is
;;;; provided with absolutely no warranty. See the COPYING and CREDITS
;;;; files for more information.
(in-package "SB!IMPL")
(def!struct (unix-host
(:make-load-form-fun make-host-load-form)
(:include host
(parse #'parse-unix-namestring)
(parse-native #'parse-native-unix-namestring)
(unparse #'unparse-unix-namestring)
(unparse-native #'unparse-native-unix-namestring)
(unparse-host #'unparse-unix-host)
(unparse-directory #'unparse-physical-directory)
(unparse-file #'unparse-unix-file)
(unparse-enough #'unparse-unix-enough)
(unparse-directory-separator "/")
(simplify-namestring #'simplify-unix-namestring)
(customary-case :lower))))
(defvar *physical-host* (make-unix-host))
;;; Take a string and return a list of cons cells that mark the char
;;; separated subseq. The first value is true if absolute directories
;;; location.
(defun split-at-slashes (namestr start end)
(declare (type simple-string namestr)
(type index start end))
(let ((absolute (and (/= start end)
(char= (schar namestr start) #\/))))
(when absolute
(incf start))
;; Next, split the remainder into slash-separated chunks.
(collect ((pieces))
(loop
(let ((slash (position #\/ namestr :start start :end end)))
(pieces (cons start (or slash end)))
(unless slash
(return))
(setf start (1+ slash))))
(values absolute (pieces)))))
(defun parse-unix-namestring (namestring start end)
(declare (type simple-string namestring)
(type index start end))
(setf namestring (coerce namestring 'simple-string))
(multiple-value-bind (absolute pieces)
(split-at-slashes namestring start end)
(multiple-value-bind (name type version)
(let* ((tail (car (last pieces)))
(tail-start (car tail))
(tail-end (cdr tail)))
(unless (= tail-start tail-end)
(setf pieces (butlast pieces))
(extract-name-type-and-version namestring tail-start tail-end)))
(when (stringp name)
(let ((position (position-if (lambda (char)
(or (char= char (code-char 0))
(char= char #\/)))
name)))
(when position
(error 'namestring-parse-error
:complaint "can't embed #\\Nul or #\\/ in Unix namestring"
:namestring namestring
:offset position))))
(let (home)
;; Deal with ~ and ~user
(when (car pieces)
(destructuring-bind (start . end) (car pieces)
(when (and (not absolute)
(not (eql start end))
(string= namestring "~"
:start1 start
:end1 (1+ start)))
(setf absolute t)
(if (> end (1+ start))
(setf home (list :home (subseq namestring (1+ start) end)))
(setf home :home))
(pop pieces))))
;; Now we have everything we want. So return it.
(values nil ; no host for Unix namestrings
nil ; no device for Unix namestrings
(collect ((dirs))
(dolist (piece pieces)
(let ((piece-start (car piece))
(piece-end (cdr piece)))
(unless (= piece-start piece-end)
(cond ((string= namestring ".."
:start1 piece-start
:end1 piece-end)
(dirs :up))
((string= namestring "**"
:start1 piece-start
:end1 piece-end)
(dirs :wild-inferiors))
(t
(dirs (maybe-make-pattern namestring
piece-start
piece-end)))))))
(cond (absolute
(if home
(list* :absolute home (dirs))
(cons :absolute (dirs))))
((dirs)
(cons :relative (dirs)))
(t
nil)))
name
type
version)))))
(defun parse-native-unix-namestring (namestring start end as-directory)
(declare (type simple-string namestring)
(type index start end))
(setf namestring (coerce namestring 'simple-string))
(multiple-value-bind (absolute ranges)
(split-at-slashes namestring start end)
(let* ((components (loop for ((start . end) . rest) on ranges
for piece = (subseq namestring start end)
collect (if (and (string= piece "..") rest)
:up
piece)))
(directory (if (and as-directory
(string/= "" (car (last components))))
components
(butlast components)))
(name-and-type
(unless as-directory
(let* ((end (first (last components)))
(dot (position #\. end :from-end t)))
;; FIXME: can we get this dot-interpretation knowledge
;; from existing code? EXTRACT-NAME-TYPE-AND-VERSION
;; does slightly more work than that.
(cond
((string= end "")
(list nil nil))
((and dot (> dot 0))
(list (subseq end 0 dot) (subseq end (1+ dot))))
(t
(list end nil)))))))
(values nil
nil
(cons (if absolute :absolute :relative) directory)
(first name-and-type)
(second name-and-type)
nil))))
(/show0 "filesys.lisp 300")
(defun unparse-unix-host (pathname)
(declare (type pathname pathname)
(ignore pathname))
;; this host designator needs to be recognized as a physical host in
;; PARSE-NAMESTRING. Until sbcl-0.7.3.x, we had "Unix" here, but
;; that's a valid Logical Hostname, so that's a bad choice. -- CSR,
;; 2002-05-09
"")
(defun unparse-unix-file (pathname)
(declare (type pathname pathname))
(collect ((strings))
(let* ((name (%pathname-name pathname))
(type (%pathname-type pathname))
(type-supplied (not (or (null type) (eq type :unspecific)))))
;; Note: by ANSI 19.3.1.1.5, we ignore the version slot when
;; translating logical pathnames to a filesystem without
;; versions (like Unix).
(when name
(when (and (null type)
(typep name 'string)
(> (length name) 0)
(position #\. name :start 1))
(error "too many dots in the name: ~S" pathname))
(when (and (typep name 'string)
(string= name ""))
(error "name is of length 0: ~S" pathname))
(strings (unparse-physical-piece name)))
(when type-supplied
(unless name
(error "cannot specify the type without a file: ~S" pathname))
(when (typep type 'simple-string)
(when (position #\. type)
(error "type component can't have a #\. inside: ~S" pathname)))
(strings ".")
(strings (unparse-physical-piece type))))
(apply #'concatenate 'simple-string (strings))))
(/show0 "filesys.lisp 406")
(defun unparse-unix-namestring (pathname)
(declare (type pathname pathname))
(concatenate 'simple-string
(unparse-physical-directory pathname)
(unparse-unix-file pathname)))
(defun unparse-native-unix-namestring (pathname as-file)
(declare (type pathname pathname))
(let* ((directory (pathname-directory pathname))
(name (pathname-name pathname))
(name-present-p (typep name '(not (member nil :unspecific))))
(name-string (if name-present-p name ""))
(type (pathname-type pathname))
(type-present-p (typep type '(not (member nil :unspecific))))
(type-string (if type-present-p type "")))
(when name-present-p
(setf as-file nil))
(coerce
(with-output-to-string (s)
(when directory
(ecase (pop directory)
(:absolute
(let ((next (pop directory)))
(cond ((eq :home next)
(write-string (user-homedir-namestring) s))
((and (consp next) (eq :home (car next)))
(let ((where (user-homedir-namestring (second next))))
(if where
(write-string where s)
(error "User homedir unknown for: ~S" (second next)))))
(next
(push next directory)))
(write-char #\/ s)))
(:relative)))
(loop for (piece . subdirs) on directory
do (typecase piece
((member :up)
(write-string ".." s))
(string
(write-string piece s))
(t
(error "ungood directory segment in NATIVE-NAMESTRING: ~S"
piece)))
if (or subdirs (stringp name))
do (write-char #\/ s)
else
do (unless as-file
(write-char #\/ s)))
(if name-present-p
(progn
(unless (stringp name-string) ;some kind of wild field
(error "ungood name component in NATIVE-NAMESTRING: ~S" name))
(write-string name-string s)
(when type-present-p
(unless (stringp type-string) ;some kind of wild field
(error "ungood type component in NATIVE-NAMESTRING: ~S" type))
(write-char #\. s)
(write-string type-string s)))
(when type-present-p ; type without a name
(error
"type component without a name component in NATIVE-NAMESTRING: ~S"
type))))
'simple-string)))
(defun unparse-unix-enough (pathname defaults)
(declare (type pathname pathname defaults))
(flet ((lose ()
(error "~S cannot be represented relative to ~S."
pathname defaults)))
(collect ((strings))
(let* ((pathname-directory (%pathname-directory pathname))
(defaults-directory (%pathname-directory defaults))
(prefix-len (length defaults-directory))
(result-directory
(cond ((null pathname-directory) '(:relative))
((eq (car pathname-directory) :relative)
pathname-directory)
((and (> prefix-len 0)
(>= (length pathname-directory) prefix-len)
(compare-component (subseq pathname-directory
0 prefix-len)
defaults-directory))
;; Pathname starts with a prefix of default. So
;; just use a relative directory from then on out.
(cons :relative (nthcdr prefix-len pathname-directory)))
((eq (car pathname-directory) :absolute)
;; We are an absolute pathname, so we can just use it.
pathname-directory)
(t
(bug "Bad fallthrough in ~S" 'unparse-unix-enough)))))
(strings (unparse-physical-directory-list result-directory)))
(let* ((pathname-type (%pathname-type pathname))
(type-needed (and pathname-type
(not (eq pathname-type :unspecific))))
(pathname-name (%pathname-name pathname))
(name-needed (or type-needed
(and pathname-name
(not (compare-component pathname-name
(%pathname-name
defaults)))))))
(when name-needed
(unless pathname-name (lose))
(when (and (null pathname-type)
(typep pathname-name 'simple-string)
(position #\. pathname-name :start 1))
(error "too many dots in the name: ~S" pathname))
(strings (unparse-physical-piece pathname-name)))
(when type-needed
(when (or (null pathname-type) (eq pathname-type :unspecific))
(lose))
(when (typep pathname-type 'simple-string)
(when (position #\. pathname-type)
(error "type component can't have a #\. inside: ~S" pathname)))
(strings ".")
(strings (unparse-physical-piece pathname-type))))
(apply #'concatenate 'simple-string (strings)))))
(defun simplify-unix-namestring (src)
(declare (type simple-string src))
(let* ((src-len (length src))
(dst (make-string src-len :element-type 'character))
(dst-len 0)
(dots 0)
(last-slash nil))
(macrolet ((deposit (char)
`(progn
(setf (schar dst dst-len) ,char)
(incf dst-len))))
(dotimes (src-index src-len)
(let ((char (schar src src-index)))
(cond ((char= char #\.)
(when dots
(incf dots))
(deposit char))
((char= char #\/)
(case dots
(0
;; either ``/...' or ``...//...'
(unless last-slash
(setf last-slash dst-len)
(deposit char)))
(1
;; either ``./...'' or ``..././...''
(decf dst-len))
(2
;; We've found ..
(cond
((and last-slash (not (zerop last-slash)))
;; There is something before this ..
(let ((prev-prev-slash
(position #\/ dst :end last-slash :from-end t)))
(cond ((and (= (+ (or prev-prev-slash 0) 2)
last-slash)
(char= (schar dst (- last-slash 2)) #\.)
(char= (schar dst (1- last-slash)) #\.))
;; The something before this .. is another ..
(deposit char)
(setf last-slash dst-len))
(t
;; The something is some directory or other.
(setf dst-len
(if prev-prev-slash
(1+ prev-prev-slash)
0))
(setf last-slash prev-prev-slash)))))
(t
;; There is nothing before this .., so we need to keep it
(setf last-slash dst-len)
(deposit char))))
(t
;; something other than a dot between slashes
(setf last-slash dst-len)
(deposit char)))
(setf dots 0))
(t
(setf dots nil)
(setf (schar dst dst-len) char)
(incf dst-len))))))
(when (and last-slash (not (zerop last-slash)))
(case dots
(1
;; We've got ``foobar/.''
(decf dst-len))
(2
;; We've got ``foobar/..''
(unless (and (>= last-slash 2)
(char= (schar dst (1- last-slash)) #\.)
(char= (schar dst (- last-slash 2)) #\.)
(or (= last-slash 2)
(char= (schar dst (- last-slash 3)) #\/)))
(let ((prev-prev-slash
(position #\/ dst :end last-slash :from-end t)))
(if prev-prev-slash
(setf dst-len (1+ prev-prev-slash))
(return-from simplify-unix-namestring
(coerce "./" 'simple-string))))))))
(cond ((zerop dst-len)
"./")
((= dst-len src-len)
dst)
(t
(subseq dst 0 dst-len)))))