lisp/nxml/rng-uri.el

   1 ;;; rng-uri.el --- URI parsing and manipulation
   2
   3 ;; Copyright (C) 2003, 2007-2011 Free Software Foundation, Inc.
   4
   5 ;; Author: James Clark
   6 ;; Keywords: XML
   7
   8 ;; This file is part of GNU Emacs.
   9
  10 ;; GNU Emacs is free software: you can redistribute it and/or modify
  11 ;; it under the terms of the GNU General Public License as published by
  12 ;; the Free Software Foundation, either version 3 of the License, or
  13 ;; (at your option) any later version.
  14
  15 ;; GNU Emacs is distributed in the hope that it will be useful,
  16 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 ;; GNU General Public License for more details.
  19
  20 ;; You should have received a copy of the GNU General Public License
  21 ;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
  22
  23 ;;; Commentary:
  24
  25 ;;; Code:
  26
  27 (defun rng-file-name-uri (f)
  28   "Return a URI for the filename F.
  29 Multibyte characters are left as is.  Use `rng-uri-escape-multibyte' to
  30 escape them using %HH."
  31   (setq f (expand-file-name f))
  32   (let ((url
  33          (replace-regexp-in-string "[\000-\032\177<>#%\"{}|\\^[]`%?;]"
  34                                    'rng-percent-encode
  35                                    f)))
  36     (concat "file:"
  37             (if (and (> (length url) 0)
  38                      (= (aref url 0) ?/))
  39                 "//"
  40               "///")
  41             url)))
  42
  43 (defun rng-uri-escape-multibyte (uri)
  44   "Escape multibyte characters in URI."
  45   (replace-regexp-in-string "[:nonascii:]"
  46                             'rng-percent-encode
  47                             (encode-coding-string uri 'utf-8)))
  48
  49 (defun rng-percent-encode (str)
  50   (apply 'concat
  51          (mapcar (lambda (ch)
  52                    (format "%%%x%x" (/ ch 16) (% ch 16)))
  53                  (string-to-list str))))
  54
  55
  56 (defun rng-uri-file-name (uri)
  57   "Return the filename represented by a URI.
  58 Signal an error if URI is not a valid file URL."
  59   (rng-uri-file-name-1 uri nil))
  60
  61 (defun rng-uri-pattern-file-name-regexp (pattern)
  62   "Return a regexp for filenames represented by URIs that match PATTERN."
  63   (rng-uri-file-name-1 pattern 'match))
  64
  65 (defun rng-uri-pattern-file-name-replace-match (pattern)
  66   (rng-uri-file-name-1 pattern 'replace))
  67
  68 ;; pattern is either nil or match or replace
  69 (defun rng-uri-file-name-1 (uri pattern)
  70   (unless (string-match "\\`\\(?:[^%]\\|%[0-9a-fA-F]{2}\\)*\\'" uri)
  71     (rng-uri-error "Bad escapes in URI `%s'" uri))
  72   (setq uri (rng-uri-unescape-multibyte uri))
  73   (let* ((components
  74           (or (rng-uri-split uri)
  75               (rng-uri-error "Cannot split URI `%s' into its components" uri)))
  76          (scheme (nth 0 components))
  77          (authority (nth 1 components))
  78          (path (nth 2 components))
  79          (absolutep (string-match "\\`/" path))
  80          (query (nth 3 components))
  81          (fragment-id (nth 4 components)))
  82     (cond ((not scheme)
  83            (unless pattern
  84              (rng-uri-error "URI `%s' does not have a scheme" uri)))
  85           ((not (string= (downcase scheme) "file"))
  86            (rng-uri-error "URI `%s' does not use the `file:' scheme" uri)))
  87     (when (not (member authority
  88                        (cons system-name '(nil "" "localhost"))))
  89       (rng-uri-error "URI `%s' does not start with `file:///' or `file://localhost/'"
  90              uri))
  91     (when query
  92       (rng-uri-error "`?' not escaped in file URI `%s'" uri))
  93     (when fragment-id
  94       (rng-uri-error "URI `%s' has a fragment identifier" uri))
  95     (when (string-match ";" path)
  96       (rng-uri-error "`;' not escaped in URI `%s'" uri))
  97     (when (string-match "%2[fF]" path) ;; 2f is hex code of slash
  98       (rng-uri-error "Escaped slash in URI `%s'" uri))
  99     (when (and (eq system-type 'windows-nt)
 100                absolutep
 101                (file-name-absolute-p (substring path 1)))
 102       (setq path (substring path 1)))
 103     (when (and pattern (string-match "\\`\\./" path))
 104       (setq path (substring path 2)))
 105     (setq path
 106           (cond ((eq pattern 'match)
 107                  (rng-uri-unescape-unibyte-match path))
 108                 ((eq pattern 'replace)
 109                  (rng-uri-unescape-unibyte-replace path 2))
 110                 (t
 111                  (rng-uri-unescape-unibyte path))))
 112     (when (string-match "\000" path)
 113       (rng-uri-error "URI `%s' has NUL character in path" uri))
 114     (when (eq pattern 'match)
 115       (setq path
 116             (concat (if absolutep
 117                         "\\(\\)"
 118                       "\\(\\(?:[^/]*/\\)*\\)")
 119                     path)))
 120     (cond ((eq pattern 'match)
 121            (concat "\\`" path "\\'"))
 122           ((and (eq pattern 'replace)
 123                 (not absolutep))
 124            (concat "\\1" path))
 125           (t path))))
 126
 127 (defun rng-uri-error (&rest args)
 128   (signal 'rng-uri-error (list (apply 'format args))))
 129
 130 (put 'rng-uri-error 'error-conditions '(error rng-uri-error))
 131 (put 'rng-uri-error 'error-message "Invalid URI")
 132
 133 (defun rng-uri-split (str)
 134   (and (string-match "\\`\\(?:\\([^:/?#]+\\):\\)?\
 135 \\(?://\\([^/?#]*\\)\\)?\
 136 \\([^?#]*\\)\
 137 \\(?:\\?\\([^#]*\\)\\)?\
 138 \\(?:#\\(\\(?:.\\|\n\\)*\\)\\)?\\'"
 139                      str)
 140        (list (match-string 1 str)
 141              (match-string 2 str)
 142              (match-string 3 str)
 143              (match-string 4 str)
 144              (match-string 5 str))))
 145
 146 (defun rng-uri-join (scheme authority path &optional query fragment-id)
 147   (when path
 148     (let (parts)
 149       (when fragment-id
 150         (setq parts (list "#" fragment-id)))
 151       (when query
 152         (setq parts
 153               (cons "?"
 154                     (cons query parts))))
 155       (setq parts (cons path parts))
 156       (when authority
 157         (setq parts
 158               (cons "//"
 159                     (cons authority parts))))
 160       (when scheme
 161         (setq parts
 162               (cons scheme
 163                     (cons ":" parts))))
 164       (apply 'concat parts))))
 165
 166 (defun rng-uri-resolve (uri-ref base-uri)
 167   "Resolve a possibly relative URI reference into absolute form.
 168 URI-REF is the URI reference to be resolved.
 169 BASE-URI is the base URI to use for resolving it.
 170 The algorithm is specified by RFC 2396.
 171 If there is some problem with URI-REF or BASE-URI, then
 172 URI-REF will be returned."
 173   (let* ((components (rng-uri-split uri-ref))
 174          (scheme (nth 0 components))
 175          (authority (nth 1 components))
 176          (path (nth 2 components))
 177          (query (nth 3 components))
 178          (fragment-id (nth 4 components))
 179          (base-components (rng-uri-split base-uri)))
 180     (if (or (not components)
 181             scheme
 182             (not base-components)
 183             (not (nth 0 base-components)))
 184         uri-ref
 185       (setq scheme (nth 0 base-components))
 186       (when (not authority)
 187         (setq authority (nth 1 base-components))
 188         (if (and (equal path "") (not query))
 189             ;; Handle same document reference by returning
 190             ;; same URI (RFC 2396bis does this too).
 191             (setq path (nth 2 base-components)
 192                   query (nth 3 base-components))
 193           (setq path (rng-resolve-path path (nth 2 base-components)))))
 194       (rng-uri-join scheme
 195                     authority
 196                     path
 197                     query
 198                     fragment-id))))
 199
 200 ;; See RFC 2396 5.2, steps 5 and 6
 201 (defun rng-resolve-path (path base-path)
 202   ;; Step 5
 203   (if (or (string-match "\\`/" path)
 204           (not (string-match "\\`/" base-path)))
 205       path
 206     ;; Step 6
 207     ;; (a), (b)
 208     (let ((segments (rng-split-path path))
 209           (base-segments (rng-split-path base-path)))
 210       (if (> (length base-segments) 1)
 211           (setq segments (nconc (nbutlast base-segments)
 212                                 segments))
 213         (setcar segments
 214                 (concat (car base-segments) (car segments))))
 215       ;; (d)
 216       (let ((last-segment (last segments)))
 217         (when (equal (car last-segment) ".")
 218           (setcar last-segment "")))
 219       ;; (c)
 220       (setq segments (delete "." segments))
 221       ;; (e)
 222       (let (iter matched)
 223         (while (progn
 224                  (setq matched nil)
 225                  (setq iter (cdr segments))
 226                  (while (and iter (not matched))
 227                    (if (or (not (equal (cadr iter) ".."))
 228                            (equal (car iter) ".."))
 229                        (setq iter (cdr iter))
 230                      (setcar iter nil)
 231                      (setcar (cdr iter)
 232                              ;; (f)
 233                              (if (cddr iter) nil ""))
 234                      (setq matched t)
 235                      (setq segments (delq nil segments))))
 236                  matched)))
 237       (rng-join-path segments))))
 238
 239 (defun rng-relative-uri (full base)
 240   "Return a URI that relative to BASE is equivalent to FULL.
 241 The returned URI will be relative if possible.
 242 Both FULL and BASE must be absolute URIs."
 243   (let* ((components (rng-uri-split full))
 244          (scheme (nth 0 components))
 245          (authority (nth 1 components))
 246          (path (nth 2 components))
 247          (query (nth 3 components))
 248          (fragment-id (nth 4 components))
 249          (base-components (rng-uri-split base)))
 250     (if (and components
 251              base-components
 252              scheme
 253              (equal scheme
 254                     (nth 0 base-components)))
 255         (progn
 256           (setq scheme nil)
 257           (when (and authority
 258                      (equal authority
 259                             (nth 1 base-components)))
 260             (setq authority nil)
 261             (setq path (rng-relative-path path (nth 2 base-components))))
 262           (rng-uri-join scheme authority path query fragment-id))
 263       full)))
 264
 265 (defun rng-relative-path (path base-path)
 266   (let ((segments (rng-split-path path))
 267         (base-segments (rng-split-path base-path)))
 268     (when (> (length base-segments) 1)
 269       (setq base-segments (nbutlast base-segments)))
 270     (if (or (member "." segments)
 271             (member ".." segments)
 272             (member "." base-segments)
 273             (member ".." base-segments))
 274         path
 275       (while (and segments
 276                   base-segments
 277                   (string= (car segments)
 278                            (car base-segments)))
 279         (setq segments (cdr segments))
 280         (setq base-segments (cdr base-segments)))
 281       (while base-segments
 282         (setq base-segments (cdr base-segments))
 283         (setq segments (cons ".." segments)))
 284       (when (equal (car segments) "")
 285         (setq segments (cons "." segments)))
 286       (rng-join-path segments))))
 287
 288 (defun rng-split-path (path)
 289   (let ((start 0)
 290         segments)
 291     (while (string-match "/" path start)
 292       (setq segments (cons (substring path start (match-beginning 0))
 293                            segments))
 294       (setq start (match-end 0)))
 295     (nreverse (cons (substring path start) segments))))
 296
 297 (defun rng-join-path (segments)
 298   (and segments
 299        (mapconcat 'identity segments "/")))
 300
 301 (defun rng-uri-unescape-multibyte (str)
 302   (replace-regexp-in-string "\\(?:%[89a-fA-F][0-9a-fA-F]\\)+"
 303                             'rng-multibyte-percent-decode
 304                             str))
 305
 306 (defun rng-multibyte-percent-decode (str)
 307   (decode-coding-string  (apply 'string
 308                                 (mapcar (lambda (h) (string-to-number h 16))
 309                                         (split-string str "%")))
 310                          'utf-8))
 311
 312 (defun rng-uri-unescape-unibyte (str)
 313   (replace-regexp-in-string "%[0-7][0-9a-fA-F]"
 314                             (lambda (h)
 315                               (string-to-number (substring h 1) 16))
 316                             str
 317                             t
 318                             t))
 319
 320 (defun rng-uri-unescape-unibyte-match (str)
 321   (replace-regexp-in-string "%[0-7][0-9a-fA-F]\\|[^%]"
 322                             (lambda (match)
 323                               (if (string= match "*")
 324                                   "\\([^/]*\\)"
 325                                 (regexp-quote
 326                                  (if (= (length match) 1)
 327                                      match
 328                                    (string-to-number (substring match 1)
 329                                                      16)))))
 330                             str
 331                             t
 332                             t))
 333
 334 (defun rng-uri-unescape-unibyte-replace (str next-match-index)
 335   (replace-regexp-in-string
 336    "%[0-7][0-9a-fA-F]\\|[^%]"
 337    (lambda (match)
 338      (if (string= match "*")
 339          (let ((n next-match-index))
 340            (setq next-match-index (1+ n))
 341            (format "\\%s" n))
 342        (let ((ch (if (= (length match) 1)
 343                      (aref match 0)
 344                    (string-to-number (substring match 1)
 345                                      16))))
 346          (if (eq ch ?\\)
 347              (string ?\\ ?\\)
 348            (string ch)))))
 349      str
 350      t
 351      t))
 352
 353 (provide 'rng-uri)
 354
 355 ;;; rng-uri.el ends here