;;; nxml-util.el --- utility functions for nxml-*.el

;; Copyright (C) 2003, 2007-2013 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:

;;; Code:

(defconst nxml-debug nil
  "Enable nxml debugging.  Effective only at compile time.")

(defsubst nxml-debug (format &rest args)
  (when nxml-debug
    (apply #'message format args)))

(defmacro nxml-debug-change (name start end)
  (when nxml-debug
    `(nxml-debug "%s: %S" ,name
                (buffer-substring-no-properties ,start ,end))))

(defmacro nxml-debug-set-inside (start end)
  (when nxml-debug
    `(let ((overlay (make-overlay ,start ,end)))
       (overlay-put overlay 'face '(:background "red"))
       (overlay-put overlay 'nxml-inside-debug t)
       (nxml-debug-change "nxml-set-inside" ,start ,end))))

(defmacro nxml-debug-clear-inside (start end)
  (when nxml-debug
    `(loop for overlay in (overlays-in ,start ,end)
           if (overlay-get overlay 'nxml-inside-debug)
           do (delete-overlay overlay)
           finally (nxml-debug-change "nxml-clear-inside" ,start ,end))))

(defun nxml-make-namespace (str)
  "Return a symbol for the namespace URI STR.
STR must be a string.  If STR is the empty string, return nil.
Otherwise, return the symbol whose name is STR prefixed with a colon."
  (if (string-equal str "")
      nil
    (intern (concat ":" str))))

(defun nxml-namespace-name (ns)
  "Return the namespace URI corresponding to the symbol NS.
This is the inverse of `nxml-make-namespace'."
  (and ns (substring (symbol-name ns) 1)))

(defconst nxml-xml-namespace-uri
  (nxml-make-namespace "http://www.w3.org/XML/1998/namespace"))

(defconst nxml-xmlns-namespace-uri
  (nxml-make-namespace "http://www.w3.org/2000/xmlns/"))

(defmacro nxml-with-degradation-on-error (context &rest body)
  (if (not nxml-debug)
      (let ((error-symbol (make-symbol "err")))
        `(condition-case ,error-symbol
             (progn ,@body)
           (error
            (nxml-degrade ,context ,error-symbol))))
    `(progn ,@body)))

(defmacro nxml-with-unmodifying-text-property-changes (&rest body)
  "Evaluate BODY without any text property changes modifying the buffer.
Any text properties changes happen as usual but the changes are not treated as
modifications to the buffer."
  (let ((modified (make-symbol "modified")))
    `(let ((,modified (buffer-modified-p))
	   (inhibit-read-only t)
	   (inhibit-modification-hooks t)
	   (buffer-undo-list t)
	   (deactivate-mark nil)
	   ;; Apparently these avoid file locking problems.
	   (buffer-file-name nil)
	   (buffer-file-truename nil))
       (unwind-protect
	   (progn ,@body)
	 (unless ,modified
	   (restore-buffer-modified-p nil))))))

(put 'nxml-with-unmodifying-text-property-changes 'lisp-indent-function 0)
(def-edebug-spec nxml-with-unmodifying-text-property-changes t)

(defmacro nxml-with-invisible-motion (&rest body)
  "Evaluate body without calling any point motion hooks."
  `(let ((inhibit-point-motion-hooks t))
     ,@body))

(put 'nxml-with-invisible-motion 'lisp-indent-function 0)
(def-edebug-spec nxml-with-invisible-motion t)

(defun nxml-display-file-parse-error (err)
  (let* ((filename (nth 1 err))
	 (buffer (find-file-noselect filename))
	 (pos (nth 2 err))
	 (message (nth 3 err)))
    (pop-to-buffer buffer)
    ;; What's the right thing to do if the buffer's modified?
    ;; The position in the saved file could be completely different.
    (goto-char (if (buffer-modified-p) 1 pos))
    (error "%s" message)))

(defun nxml-signal-file-parse-error (file pos message &optional error-symbol)
  (signal (or error-symbol 'nxml-file-parse-error)
	  (list file pos message)))

(put 'nxml-file-parse-error
     'error-conditions
     '(error nxml-file-parse-error))

(put 'nxml-parse-file-error
     'error-message
     "Error parsing file")

(provide 'nxml-util)

;;; nxml-util.el ends here
