unparse.lisp

   1 ;;; -*- show-trailing-whitespace: t; indent-tabs-mode: nil -*-
   2
   3 ;;; Copyright (c) 2007,2008 David Lichteblau, Ivan Shvedunov.
   4 ;;; Copyright (c) 2004 David Lichteblau (for headcraft.de)
   5 ;;; All rights reserved.
   6
   7 ;;; Redistribution and use in source and binary forms, with or without
   8 ;;; modification, are permitted provided that the following conditions
   9 ;;; are met:
  10 ;;;
  11 ;;;   * Redistributions of source code must retain the above copyright
  12 ;;;     notice, this list of conditions and the following disclaimer.
  13 ;;;
  14 ;;;   * Redistributions in binary form must reproduce the above
  15 ;;;     copyright notice, this list of conditions and the following
  16 ;;;     disclaimer in the documentation and/or other materials
  17 ;;;     provided with the distribution.
  18 ;;;
  19 ;;; THIS SOFTWARE IS PROVIDED BY THE AUTHOR 'AS IS' AND ANY EXPRESSED
  20 ;;; OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  21 ;;; WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22 ;;; ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
  23 ;;; DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24 ;;; DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
  25 ;;; GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  26 ;;; INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
  27 ;;; WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  28 ;;; NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  29 ;;; SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  30
  31 (in-package :xuriella)
  32
  33
  34 ;;; Convenience functions for serialization to SAX, similar in syntax
  35 ;;; to what cxml offers, but with namespace handling as required for XSLT.
  36
  37 (defvar *current-element*)
  38 (defvar *sink*)
  39 (defvar *start-tag-written-p*)
  40
  41 (defmacro with-xml-output (sink &body body)
  42   `(invoke-with-xml-output (lambda () ,@body) ,sink))
  43
  44 (defmacro with-output-sink-bound ((var) &body body)
  45   `(invoke-with-output-sink-bound (lambda (,var) ,@body)))
  46
  47 (defun invoke-with-xml-output (fn sink)
  48   (let ((*sink* sink)
  49         (*current-element* nil)
  50         (*start-tag-written-p* t))
  51     (sax:start-document *sink*)
  52     (funcall fn)
  53     (sax:end-document *sink*)))
  54
  55 (defun invoke-with-output-sink-bound (fn)
  56   (maybe-emit-start-tag)
  57   (funcall fn *sink*))
  58
  59 (defmacro with-element
  60     ((local-name uri &key suggested-prefix extra-namespaces process-aliases)
  61      &body body)
  62   `(invoke-with-element (lambda () ,@body)
  63                         ,local-name
  64                         ,uri
  65                         :suggested-prefix ,suggested-prefix
  66                         :extra-namespaces ,extra-namespaces
  67                         :process-aliases ,process-aliases))
  68
  69 (defun doctype (name public-id system-id &optional internal-subset)
  70   (sax:start-dtd *sink* name public-id system-id)
  71   (when internal-subset
  72     (sax:unparsed-internal-subset *sink* internal-subset))
  73   (sax:end-dtd *sink*))
  74
  75 (defun maybe-emit-start-tag ()
  76   (let ((elt *current-element*))
  77     (when (and elt (not *start-tag-written-p*))
  78       (setf *start-tag-written-p* t)
  79       (let* ((local-name (sink-element-local-name elt))
  80              (uri (sink-element-uri elt))
  81              (suggested-prefix (sink-element-suggested-prefix elt))
  82              (prefix (ensure-prefix-for-uri elt uri suggested-prefix))
  83              (qname (if (plusp (length prefix))
  84                         (concatenate 'string prefix ":" local-name)
  85                         local-name))
  86              (attrs '()))
  87         (setf (sink-element-actual-qname elt) qname)
  88         (dolist (attr (sink-element-attributes elt))
  89           (push (convert-attribute elt attr) attrs))
  90         (loop
  91            for (prefix . uri) in (sink-element-new-namespaces elt) do
  92              (sax:start-prefix-mapping *sink* prefix uri)
  93              (push (make-xmlns-attribute prefix uri) attrs))
  94         (sax:start-element *sink* uri local-name qname attrs)))))
  95
  96 (defun convert-attribute (elt attr)
  97   (let* ((local-name (sink-attribute-local-name attr))
  98          (uri (sink-attribute-uri attr))
  99          (suggested-prefix (sink-attribute-suggested-prefix attr))
 100          (prefix (ensure-prefix-for-uri elt uri suggested-prefix t))
 101          (qname (if (plusp (length prefix))
 102                     (concatenate 'string prefix ":" local-name)
 103                     local-name)))
 104     (sax:make-attribute :namespace-uri uri
 105                         :local-name local-name
 106                         :qname qname
 107                         :value (sink-attribute-value attr))))
 108
 109 (defun sink-element-find-uri (prefix elt)
 110   (assert prefix)
 111   (cdr
 112    (find prefix
 113          (sink-element-all-namespaces elt)
 114          :key #'car
 115          :test #'equal)))
 116
 117 (defun ensure-prefix-for-uri (elt uri suggested-prefix &optional attributep)
 118   (check-type uri string)
 119   (setf suggested-prefix (or suggested-prefix "")) ;zzz
 120   (when (or (equal suggested-prefix "xmlns")
 121             (equal suggested-prefix "xml"))
 122     (setf suggested-prefix nil))
 123   (let* ((prefix-cons
 124           (find uri
 125                 (sink-element-all-namespaces elt)
 126                 :key #'cdr
 127                 :test #'equal))
 128          (prefix (car prefix-cons))
 129          (cross-check
 130           (when prefix-cons
 131             (sink-element-find-uri prefix elt))))
 132     (cond
 133       ((equal uri "")
 134        (unless (or attributep
 135                    (equal (sink-element-find-uri "" elt) ""))
 136          (push-sink-element-namespace elt "" ""))
 137        "")
 138       ((and (or (plusp (length suggested-prefix))
 139                 (not attributep))
 140             (not (find suggested-prefix
 141                        (sink-element-new-namespaces elt)
 142                        :key #'car
 143                        :test #'equal))
 144             (not (find suggested-prefix
 145                        (sink-element-used-prefixes elt)
 146                        :test #'equal)))
 147        (push-sink-element-namespace elt suggested-prefix uri)
 148        suggested-prefix)
 149       ((and prefix-cons
 150             (equal cross-check uri)
 151             (or (plusp (length prefix))
 152                 (not attributep)))
 153        (pushnew prefix (sink-element-used-prefixes elt) :test #'equal)
 154        prefix)
 155       (t
 156        (loop
 157            for i from 0
 158            for prefix = (format nil "ns-~D" i)
 159            while (sink-element-find-uri prefix elt)
 160            finally
 161              (push-sink-element-namespace elt prefix uri)
 162              (return prefix))))))
 163
 164 (defun make-xmlns-attribute (prefix uri)
 165   (sax:make-attribute
 166    :namespace-uri #"http://www.w3.org/2000/xmlns/"
 167    :local-name prefix
 168    :qname (if (zerop (length prefix))
 169               "xmlns"
 170               (concatenate 'string "xmlns:" prefix))
 171    :value uri))
 172
 173 (defstruct sink-element
 174   local-name
 175   uri
 176   suggested-prefix
 177   all-namespaces
 178   new-namespaces
 179   used-prefixes
 180   attributes
 181   actual-qname)
 182
 183 (defstruct sink-attribute
 184   local-name
 185   uri
 186   suggested-prefix
 187   value)
 188
 189 (defparameter *initial-namespaces*
 190   '(("" . "")
 191     ("xmlns" . #"http://www.w3.org/2000/xmlns/")
 192     ("xml" . #"http://www.w3.org/XML/1998/namespace")))
 193
 194 (defun invoke-with-element
 195     (fn local-name uri &key suggested-prefix extra-namespaces process-aliases)
 196   (check-type local-name string)
 197   (check-type uri string)
 198   (check-type suggested-prefix (or null string))
 199   (maybe-emit-start-tag)
 200   (when process-aliases
 201     (setf uri (unalias-uri uri)))
 202   (let* ((parent *current-element*)
 203          (elt (make-sink-element
 204                :local-name local-name
 205                :uri uri
 206                :suggested-prefix suggested-prefix
 207                :all-namespaces (if parent
 208                                    (sink-element-all-namespaces parent)
 209                                    *initial-namespaces*)
 210                :new-namespaces nil
 211                :attributes nil))
 212          (*current-element* elt)
 213          (*start-tag-written-p* nil))
 214     ;; always establish explicitly copied namespaces first
 215     ;; (not including declarations of the default namespace)
 216     (process-extra-namespaces elt extra-namespaces process-aliases)
 217     ;; establish the element's prefix (which might have to be the default
 218     ;; namespace if it's the empty URI)
 219     (ensure-prefix-for-uri elt uri suggested-prefix)
 220     ;; we'll do attributes incrementally
 221     (multiple-value-prog1
 222         (funcall fn)
 223       (maybe-emit-start-tag)
 224       (sax:end-element *sink* uri local-name (sink-element-actual-qname elt))
 225       (loop
 226          for (prefix . uri) in (sink-element-new-namespaces elt) do
 227          (sax:end-prefix-mapping *sink* prefix)))))
 228
 229 (defun process-extra-namespace (elt prefix uri process-aliases)
 230   (when process-aliases
 231     (setf uri (unalias-uri uri)))
 232   (unless
 233       (or
 234        ;; don't touch the empty prefix, since we might need it for the empty
 235        ;; URI
 236        (zerop (length prefix))
 237        ;; don't touch the empty URI
 238        (zerop (length uri))
 239        ;; allow earlier conses in extra-namespaces to hide later ones.
 240        ;; FIXME: add a good explanation here why we need to do this both
 241        ;; here and in remove-extra-namespaces.
 242        (find prefix
 243              (sink-element-new-namespaces elt)
 244              :key #'car
 245              :test #'equal))
 246     (let ((previous (sink-element-find-uri prefix elt)))
 247       (if (equal uri previous) ;no need to declare what has already been done
 248           (pushnew prefix (sink-element-used-prefixes elt) :test #'equal)
 249           (push-sink-element-namespace elt prefix uri)))))
 250
 251 (defun process-extra-namespaces (elt extra-namespaces process-aliases)
 252   (loop for (prefix . uri) in extra-namespaces do
 253        (process-extra-namespace elt prefix uri process-aliases)))
 254
 255 (defun push-sink-element-namespace (elt prefix uri)
 256   (assert prefix)
 257   (cond
 258     ((equal prefix "xml")
 259      (assert (equal uri "http://www.w3.org/XML/1998/namespace")))
 260     ((equal prefix "xmlns")
 261      (assert (equal uri "http://www.w3.org/2000/xmlns/")))
 262     (t
 263      (let ((cons (cons prefix uri)))
 264        (push cons (sink-element-all-namespaces elt))
 265        (push cons (sink-element-new-namespaces elt))))))
 266
 267 (defun write-attribute
 268     (local-name uri value &key suggested-prefix process-aliases)
 269   (check-type local-name string)
 270   (check-type uri string)
 271   (check-type value string)
 272   (check-type suggested-prefix (or null string))
 273   (when process-aliases
 274     (setf uri (unalias-uri uri)))
 275   (cond
 276     ((null *current-element*)
 277      (xslt-error "attribute outside of element"))
 278     (*start-tag-written-p*
 279      (xslt-cerror "attribute after start tag"))
 280     ((equal local-name "xmlns")
 281      (xslt-error "attribute named xmlns"))
 282     (t
 283      (setf (sink-element-attributes *current-element*)
 284            (cons (make-sink-attribute :local-name local-name
 285                                       :uri uri
 286                                       :suggested-prefix suggested-prefix
 287                                       :value value)
 288                  (delete-if (lambda (x)
 289                               (and (equal (sink-attribute-local-name x)
 290                                           local-name)
 291                                    (equal (sink-attribute-uri x) uri)))
 292                             (sink-element-attributes *current-element*)))))))
 293
 294 (defun write-extra-namespace (prefix uri process-aliases)
 295   (check-type prefix string)
 296   (check-type uri string)
 297   (cond
 298     ((null *current-element*)
 299      (xslt-error "attribute outside of element"))
 300     (*start-tag-written-p*
 301      (xslt-cerror "namespace after start tag"))
 302     ((zerop (length prefix))
 303      (xslt-cerror "refusing to copy declaration for default namespace"))
 304     (t
 305      (process-extra-namespace *current-element* prefix uri process-aliases))))
 306
 307 (defun write-text (data)
 308   (maybe-emit-start-tag)
 309   (sax:characters *sink* data)
 310   data)
 311
 312 (defun write-comment (data)
 313   (maybe-emit-start-tag)
 314   (sax:comment *sink* data)
 315   data)
 316
 317 (defun write-processing-instruction (target data)
 318   (maybe-emit-start-tag)
 319   (sax:processing-instruction *sink* target data)
 320   data)
 321
 322 (defun write-unescaped (str)
 323   (maybe-emit-start-tag)
 324   (sax:unescaped *sink* str))