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emacs/lisp/nxml/nxml-parse.el

319 lines
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EmacsLisp

;;; nxml-parse.el --- XML parser, sharing infrastructure with nxml-mode
;; Copyright (C) 2003, 2007-2014 Free Software Foundation, Inc.
;; Author: James Clark
;; Keywords: XML
;; This file is part of GNU Emacs.
;; GNU Emacs is free software: you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation, either version 3 of the License, or
;; (at your option) any later version.
;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;; GNU General Public License for more details.
;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>.
;;; Commentary:
;; Entry point is `nxml-parse-file'.
;;; Code:
(require 'nxml-util)
(require 'xmltok)
(require 'nxml-enc)
(require 'nxml-ns)
(defvar nxml-parse-file-name nil)
(defvar nxml-validate-function nil
"Either nil or a function called by `nxml-parse-file' to perform validation.
The function will be called once for each start-tag or end-tag. The
function is passed two arguments TEXT and START-TAG. For a start-tag,
START-TAG is a list (NAME ATTRIBUTES) where NAME and ATTRIBUTES are in
the same form as returned by `nxml-parse-file'. For an end-tag,
START-TAG is nil. TEXT is a string containing the text immediately
preceding the tag, or nil if there was no such text. An empty element
is treated as a start-tag followed by an end-tag.
For a start-tag, the namespace state will be the state after
processing the namespace declarations in the start-tag. For an
end-tag, the namespace state will be the state before popping the
namespace declarations for the corresponding start-tag.
The function must return nil if no error is detected or a
cons (MESSAGE . LOCATION) where MESSAGE is a string containing
an error message and LOCATION indicates what caused the error
as follows:
- nil indicates the tag as whole caused it; this is always allowed;
- text indicates the text caused it; this is allowed only if
TEXT is non-nil;
- tag-close indicates the close of the tag caused it; this is
allowed only if START-TAG is non-nil;
- (attribute-name . N) indicates that the name of the Nth attribute
caused it; N counts from 0; this is allowed only if START-TAG is non-nil
and N must be less than the number of attributes;
- (attribute-value . N) indicates that the value of the Nth attribute
caused it; N counts from 0; this is allowed only if START-TAG is non-nil
and N must be less than the number of attributes.")
(defun nxml-parse-file (file)
"Parse the XML document in FILE and return it as a list.
An XML element is represented as a list (NAME ATTRIBUTES . CHILDREN).
NAME is either a string, in the case where the name does not have a
namespace, or a cons (NAMESPACE . LOCAL-NAME), where NAMESPACE is a
symbol and LOCAL-NAME is a string, in the case where the name does
have a namespace. NAMESPACE is a keyword whose name is `:URI', where
URI is the namespace name. ATTRIBUTES is an alist of attributes where
each attribute has the form (NAME . VALUE), where NAME has the same
form as an element name, and VALUE is a string. A namespace
declaration is represented as an attribute whose name is
\(:http://www.w3.org/2000/xmlns/ . LOCAL-NAME). CHILDREN is a list
containing strings and child elements; CHILDREN never contains two
consecutive strings and never contains an empty string. Processing
instructions and comments are not represented. The return value is a
list representing the document element.
If the XML document is not well-formed, an error having the condition
`nxml-file-parse-error' will be signaled; the error data will be a
list of the form \(FILE POSITION MESSAGE), where POSITION is an
integer specifying the position where the error was detected, and
MESSAGE is a string describing the error.
The current contents of FILE will be parsed even if there is a
modified buffer currently visiting FILE.
If the variable `nxml-validate-function' is non-nil, it will be called
twice for each element, and any reported error will be signaled in the
same way as well-formedness error."
(with-current-buffer (nxml-parse-find-file file)
(unwind-protect
(let ((nxml-parse-file-name file))
(nxml-parse-instance))
(kill-buffer nil))))
(defun nxml-parse-find-file (file)
(with-current-buffer (get-buffer-create " *nXML Parse*")
(erase-buffer)
(let ((set-auto-coding-function 'nxml-set-xml-coding))
(insert-file-contents file))
(current-buffer)))
(defun nxml-parse-instance ()
(let (xmltok-dtd)
(xmltok-save
(xmltok-forward-prolog)
(nxml-check-xmltok-errors)
(nxml-ns-save
(nxml-parse-instance-1)))))
(defun nxml-parse-instance-1 ()
(let* ((top (cons nil nil))
;; tail is a cons cell, whose cdr is nil
;; additional elements will destructively appended to tail
(tail top)
;; stack of tails one for each open element
tail-stack
;; list of QNames of open elements
open-element-tags
;; list of strings buffering a text node, in reverse order
text
;; position of beginning of first (in buffer) string in text
text-pos)
(while (xmltok-forward)
(nxml-check-xmltok-errors)
(cond ((memq xmltok-type '(start-tag end-tag empty-element))
(when text
(setq text (apply 'concat (nreverse text)))
(setcdr tail (cons text nil))
(setq tail (cdr tail)))
(when (not (eq xmltok-type 'end-tag))
(when (and (not open-element-tags)
(not (eq tail top)))
(nxml-parse-error nil "Multiple top-level elements"))
(setq open-element-tags
(cons (xmltok-start-tag-qname)
open-element-tags))
(nxml-ns-push-state)
(let ((tag (nxml-parse-start-tag)))
(nxml-validate-tag text text-pos tag)
(setq text nil)
(setcdr tail (cons tag nil))
(setq tail (cdr tail))
(setq tail-stack (cons tail tail-stack))
(setq tail (last tag))))
(when (not (eq xmltok-type 'start-tag))
(or (eq xmltok-type 'empty-element)
(equal (car open-element-tags)
(xmltok-end-tag-qname))
(if open-element-tags
(nxml-parse-error nil
"Unbalanced end-tag; expected </%s>"
(car open-element-tags))
(nxml-parse-error nil "Extra end-tag")))
(nxml-validate-tag text text-pos nil)
(setq text nil)
(nxml-ns-pop-state)
(setq open-element-tags (cdr open-element-tags))
(setq tail (car tail-stack))
(setq tail-stack (cdr tail-stack)))
(setq text-pos nil))
((memq xmltok-type '(space data entity-ref char-ref cdata-section))
(cond (open-element-tags
(unless text-pos
(setq text-pos xmltok-start))
(setq text
(cons (nxml-current-text-string) text)))
((not (eq xmltok-type 'space))
(nxml-parse-error
nil
"%s at top-level"
(cdr (assq xmltok-type
'((data . "Text characters")
(entity-ref . "Entity reference")
(char-ref . "Character reference")
(cdata-section . "CDATA section"))))))))))
(unless (cdr top)
(nxml-parse-error (point-max) "Missing document element"))
(cadr top)))
(defun nxml-parse-start-tag ()
(let (parsed-attributes
parsed-namespace-attributes
atts att prefixes prefix ns value name)
(setq atts xmltok-namespace-attributes)
(while atts
(setq att (car atts))
(setq value (or (xmltok-attribute-value att)
(nxml-parse-error nil "Invalid attribute value")))
(setq ns (nxml-make-namespace value))
(setq prefix (and (xmltok-attribute-prefix att)
(xmltok-attribute-local-name att)))
(cond ((member prefix prefixes)
(nxml-parse-error nil "Duplicate namespace declaration"))
((not prefix)
(nxml-ns-set-default ns))
(ns
(nxml-ns-set-prefix prefix ns))
(t (nxml-parse-error nil "Cannot undeclare namespace prefix")))
(setq prefixes (cons prefix prefixes))
(setq parsed-namespace-attributes
(cons (cons (nxml-make-name nxml-xmlns-namespace-uri
(xmltok-attribute-local-name att))
value)
parsed-namespace-attributes))
(setq atts (cdr atts)))
(setq name
(nxml-make-name
(let ((prefix (xmltok-start-tag-prefix)))
(if prefix
(or (nxml-ns-get-prefix prefix)
(nxml-parse-error (1+ xmltok-start)
"Prefix `%s' undeclared"
prefix))
(nxml-ns-get-default)))
(xmltok-start-tag-local-name)))
(setq atts xmltok-attributes)
(while atts
(setq att (car atts))
(setq ns
(let ((prefix (xmltok-attribute-prefix att)))
(and prefix
(or (nxml-ns-get-prefix prefix)
(nxml-parse-error (xmltok-attribute-name-start att)
"Prefix `%s' undeclared"
prefix)))))
(setq parsed-attributes
(let ((nm (nxml-make-name ns
(xmltok-attribute-local-name att))))
(when (assoc nm parsed-attributes)
(nxml-parse-error (xmltok-attribute-name-start att)
"Duplicate attribute"))
(cons (cons nm (or (xmltok-attribute-value att)
(nxml-parse-error nil "Invalid attribute value")))
parsed-attributes)))
(setq atts (cdr atts)))
;; We want to end up with the attributes followed by the
;; the namespace attributes in the same order as
;; xmltok-attributes and xmltok-namespace-attributes respectively.
(when parsed-namespace-attributes
(setq parsed-attributes
(nconc parsed-namespace-attributes parsed-attributes)))
(list name (nreverse parsed-attributes))))
(defun nxml-validate-tag (text text-pos tag)
(when nxml-validate-function
(let ((err (funcall nxml-validate-function text tag))
pos)
(when err
(setq pos (nxml-validate-error-position (cdr err)
(and text text-pos)
tag))
(or pos (error "Incorrect return value from %s"
nxml-validate-function))
(nxml-parse-error pos (car err))))))
(defun nxml-validate-error-position (location text-pos tag)
(cond ((null location) xmltok-start)
((eq location 'text) text-pos)
((eq location 'tag-close)
(and tag (- (point) (if (eq xmltok-type 'empty-element ) 2 1))))
((consp location)
(let ((att (nth (cdr location) xmltok-attributes)))
(when (not att)
(setq att (nth (- (cdr location) (length xmltok-attributes))
xmltok-namespace-attributes)))
(cond ((not att))
((eq (car location) 'attribute-name)
(xmltok-attribute-name-start att))
((eq (car location) 'attribute-value)
(xmltok-attribute-value-start att)))))))
(defun nxml-make-name (ns local-name)
(if ns
(cons ns local-name)
local-name))
(defun nxml-current-text-string ()
(cond ((memq xmltok-type '(space data))
(buffer-substring-no-properties xmltok-start
(point)))
((eq xmltok-type 'cdata-section)
(buffer-substring-no-properties (+ xmltok-start 9)
(- (point) 3)))
((memq xmltok-type '(char-ref entity-ref))
(unless xmltok-replacement
(nxml-parse-error nil
(if (eq xmltok-type 'char-ref)
"Reference to unsupported Unicode character"
"Unresolvable entity reference")))
xmltok-replacement)))
(defun nxml-parse-error (position &rest args)
(nxml-signal-file-parse-error nxml-parse-file-name
(or position xmltok-start)
(apply 'format args)))
(defun nxml-check-xmltok-errors ()
(when xmltok-errors
(let ((err (car (last xmltok-errors))))
(nxml-signal-file-parse-error nxml-parse-file-name
(xmltok-error-start err)
(xmltok-error-message err)))))
(provide 'nxml-parse)
;;; nxml-parse.el ends here