;;; lisp-mnt.el --- utility functions for Emacs Lisp maintainers  -*- lexical-binding:t -*-

;; Copyright (C) 1992, 1994, 1997, 2000-2021 Free Software Foundation,
;; Inc.

;; Author: Eric S. Raymond <esr@snark.thyrsus.com>
;; Maintainer: emacs-devel@gnu.org
;; Created: 14 Jul 1992
;; Keywords: docs
;; X-Bogus-Bureaucratic-Cruft: Gruad will get you if you don't watch out!

;; 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 <https://www.gnu.org/licenses/>.

;;; Commentary:

;; This library adds some services to Emacs-Lisp editing mode.
;;
;; First, it knows about the header conventions for library packages.
;; One entry point supports generating synopses from a library directory.
;; Another can be used to check for missing headers in library files.
;;
;; Another entry point automatically addresses bug mail to a package's
;; maintainer or author.

;; This file can be loaded by your emacs-lisp-mode-hook.  Have it
;; (require 'lisp-mnt)

;; This file is an example of the header conventions.  Note the following
;; features:
;;
;;    * Header line --- makes it possible to extract a one-line summary of
;; the package's uses automatically for use in library synopses, KWIC
;; indexes and the like.
;;
;;    Format is three semicolons, followed by the filename, followed by
;; three dashes, followed by the summary.  All fields space-separated.
;;
;;    * A blank line
;;
;;    * Copyright line, which looks more or less like this:
;;
;;       ;; Copyright (C) 1999, 2000, 2001 Free Software Foundation, Inc.
;;
;;    * A blank line
;;
;;    * Author line --- contains the name and net address of at least
;; the principal author.
;;
;;    If there are multiple authors, they should be listed on continuation
;; lines led by ;;<TAB>, like this:
;;
;; ;; Author: Ashwin Ram <Ram-Ashwin@cs.yale.edu>
;; ;;	Dave Sill <de5@ornl.gov>
;; ;;	David Lawrence <tale@pawl.rpi.edu>
;; ;;	Noah Friedman <friedman@ai.mit.edu>
;; ;;	Joe Wells <jbw@maverick.uswest.com>
;; ;;	Dave Brennan <brennan@hal.com>
;; ;;	Eric Raymond <esr@snark.thyrsus.com>
;;
;;    * Maintainer line --- should be a single name/address as in the Author
;; line, or an address only.  If there is no maintainer
;; line, the person(s) in the Author field are presumed to be it.
;;    The idea behind these two fields is to be able to write a Lisp function
;; that does "send mail to the author" without having to mine the name out by
;; hand.  Please be careful about surrounding the network address with <> if
;; there's also a name in the field.
;;
;;    * Created line --- optional, gives the original creation date of the
;; file.  For historical interest, basically.
;;
;;    * Version line --- intended to give the reader a clue if they're looking
;; at a different version of the file than the one they're accustomed to.  This
;; may be an RCS or SCCS header.
;;
;;    * Adapted-By line --- this was used historically when some files
;; were added to Emacs.  The person named in this field installed and
;; (possibly adapted) the package in the Emacs distribution.
;;
;;    * Keywords line --- used by the finder code for finding Emacs
;; Lisp code related to a topic.
;;
;;    * X-Bogus-Bureaucratic-Cruft line --- this is a joke and an example
;; of a comment header.  Headers starting with `X-' should never be used
;; for any real purpose; this is the way to safely add random headers
;; without invoking the wrath of any program.
;;
;;    * Commentary line --- enables Lisp code to find the developer's and
;; maintainers' explanations of the package internals.
;;
;;    * Change log line --- optional, exists to terminate the commentary
;; section and start a change-log part, if one exists.
;;
;;    * Code line --- exists so Lisp can know where commentary and/or
;; change-log sections end.
;;
;;    * Footer line --- marks end-of-file so it can be distinguished from
;; an expanded formfeed or the results of truncation.

;;; Change Log:

;; Tue Jul 14 23:44:17 1992	ESR
;;	* Created.

;;; Code:

;;; Variables:

(defgroup lisp-mnt nil
  "Utility functions for Emacs Lisp maintainers."
  :prefix "lm-"
  :group 'maint)

;; At least some of these defcustoms should probably be defconsts,
;; since they define, or are defined by, the header format.  -- fx

(defcustom lm-header-prefix "^;+[ \t]+\\(@(#)\\)?[ \t]*\\$?"
  "Prefix that is ignored before the tag.
For example, you can write the 1st line synopsis string and headers like this
in your Lisp package:

   ;; @(#) package.el -- package description
   ;;
   ;; @(#) $Maintainer:   Person Foo Bar $

The @(#) construct is used by unix what(1) and
then $identifier: doc string $ is used by GNU ident(1)"
  :type 'regexp)

(defcustom lm-copyright-prefix "^\\(;+[ \t]\\)+Copyright (C) "
  "Prefix that is ignored before the dates in a copyright.
Leading comment characters and whitespace should be in regexp group 1."
  :type 'regexp)

(defcustom lm-comment-column 16
  "Column used for placing formatted output."
  :type 'integer)

(defcustom lm-any-header ".*"
  "Regexp which matches start of any section."
  :type 'regexp)

(defcustom lm-commentary-header "Commentary\\|Documentation"
  "Regexp which matches start of documentation section."
  :type 'regexp)

(defcustom lm-history-header "Change ?Log\\|History"
  "Regexp which matches the start of code log section."
  :type 'regexp)

;;; Functions:

;; These functions all parse the headers of the current buffer

(defun lm-get-header-re (header &optional mode)
  "Return regexp for matching HEADER.
If called with optional MODE and with value `section',
return section regexp instead."
  (if (eq mode 'section)
      (concat "^;;;;* \\(" header "\\):[ \t]*$")
    (concat lm-header-prefix "\\(" header "\\)[ \t]*:[ \t]*")))

(defun lm-get-package-name ()
  "Return package name by looking at the first line."
  (save-excursion
    (goto-char (point-min))
    (if (and (looking-at (concat lm-header-prefix))
	     (progn (goto-char (match-end 0))
		    (looking-at "\\([^\t ]+\\)")
		    (match-end 1)))
	(match-string-no-properties 1))))

(defun lm-section-start (header &optional after)
  "Return the buffer location of a given section start marker.
The HEADER is the section mark string to search for.
If AFTER is non-nil, return the location of the next line.
If the given section does not exist, return nil."
  (save-excursion
    (let ((case-fold-search t))
      (goto-char (point-min))
      (if (re-search-forward (lm-get-header-re header 'section) nil t)
          (line-beginning-position (if after 2))))))
(defalias 'lm-section-mark 'lm-section-start)

(defun lm-section-end (header)
  "Return the buffer location of the end of a given section.
The HEADER is the section string marking the beginning of the
section.  If the given section does not exist, return nil.

The section ends before the first non-comment text or the next
section of the same level or lower; whatever comes first.  The
function `lisp-outline-level' is used to compute the level of
a section."
  (require 'outline)   ;; for outline-regexp.
  (let ((start (lm-section-start header)))
    (when start
      (save-excursion
        (goto-char start)
        (let ((level (lisp-outline-level))
              (case-fold-search t)
              next-section-found)
          (beginning-of-line 2)
          (while (and (setq next-section-found
                            (re-search-forward
                             (lm-get-header-re lm-any-header 'section)
                             nil t))
                      (> (save-excursion
                           (beginning-of-line)
                           (lisp-outline-level))
                         level)))
	  (min (if next-section-found
		   (progn (beginning-of-line 0)
			  (unless (looking-at "")
			    (beginning-of-line 2))
			  (point))
		 (point-max))
	       (progn (goto-char start)
		      (while (forward-comment 1))
		      (point))))))))

(defun lm-code-start ()
  "Return the buffer location of the `Code' start marker."
  (lm-section-start "Code"))
(defalias 'lm-code-mark 'lm-code-start)

(defun lm-commentary-start ()
  "Return the buffer location of the `Commentary' start marker."
  (lm-section-start lm-commentary-header))
(defalias 'lm-commentary-mark 'lm-commentary-start)

(defun lm-commentary-end ()
  "Return the buffer location of the `Commentary' section end."
  (lm-section-end lm-commentary-header))

(defun lm-history-start ()
  "Return the buffer location of the `History' start marker."
  (lm-section-start lm-history-header))
(defalias 'lm-history-mark 'lm-history-start)

(defun lm-copyright-mark ()
  "Return the buffer location of the `Copyright' line."
  (save-excursion
    (let ((case-fold-search t))
      (goto-char (point-min))
      (if (re-search-forward lm-copyright-prefix nil t)
	  (point)))))

(defun lm-header (header)
  "Return the contents of the header named HEADER."
  (goto-char (point-min))
  (let ((case-fold-search t))
    (when (and (re-search-forward (lm-get-header-re header) (lm-code-mark) t)
	       ;;   RCS ident likes format "$identifier: data$"
	       (looking-at
		(if (save-excursion
		      (skip-chars-backward "^$" (match-beginning 0))
		      (= (point) (match-beginning 0)))
		    "[^\n]+" "[^$\n]+")))
      (match-string-no-properties 0))))

(defun lm-header-multiline (header)
  "Return the contents of the header named HEADER, with continuation lines.
The returned value is a list of strings, one per line."
  (save-excursion
    (goto-char (point-min))
    (let ((res (lm-header header)))
      (when res
	(setq res (list res))
	(forward-line 1)
	(while (looking-at "^;+\\(\t\\|[\t\s]\\{2,\\}\\)\\(.+\\)")
	  (push (match-string-no-properties 2) res)
	  (forward-line 1)))
      (nreverse res))))

;; These give us smart access to the header fields and commentary

(defmacro lm-with-file (file &rest body)
  "Execute BODY in a buffer containing the contents of FILE.
If FILE is nil, execute BODY in the current buffer."
  (declare (indent 1) (debug t))
  (let ((filesym (make-symbol "file")))
    `(let ((,filesym ,file))
       (if ,filesym
	   (with-temp-buffer
	     (insert-file-contents ,filesym)
	     (emacs-lisp-mode)
	     ,@body)
	 (save-excursion
           (save-restriction
             (widen)
             (goto-char (point-min))
             ;; Switching major modes is too drastic, so just switch
             ;; temporarily to the Emacs Lisp mode syntax table.
             (with-syntax-table emacs-lisp-mode-syntax-table
               ,@body)))))))

;; Fixme: Probably this should be amalgamated with copyright.el; also
;; we need a check for ranges in copyright years.

(defun lm-crack-copyright (&optional file)
  "Return the copyright holder, and a list of copyright years.
Use the current buffer if FILE is nil.
Return argument is of the form (\"HOLDER\" \"YEAR1\" ... \"YEARN\")"
  (lm-with-file file
    (goto-char (lm-copyright-mark))
    (let ((holder nil)
	  (years nil)
	  (start (point))
	  (end (line-end-position)))
      ;; Cope with multi-line copyright `lines'.  Assume the second
      ;; line is indented at least as much as the original, with the
      ;; same commenting style.
      (save-excursion
	(beginning-of-line 2)
	(let ((str (match-string-no-properties 1)))
	  (beginning-of-line)
	  (while (and (looking-at str) (not (looking-at lm-copyright-prefix)))
	    (setq end (line-end-position))
	    (beginning-of-line 2))))
      ;; Make a single line and parse that.
      (let ((buff (current-buffer)))
	(with-temp-buffer
	  (insert-buffer-substring buff start end)
	  (goto-char (point-min))
	  (while (re-search-forward "^;+[ \t]+" nil t)
	    (replace-match ""))
	  (goto-char (point-min))
	  (while (re-search-forward " *\n" nil t)
	    (replace-match " "))
	  (goto-char (point-min))
	  (while (re-search-forward "\\([0-9]+\\),? +" nil t)
	    (setq years (cons (match-string-no-properties 1) years)))
	  (if (looking-at ".*$")
	      (setq holder (match-string-no-properties 0)))))
      (cons holder (nreverse years)))))

(defun lm-summary (&optional file)
  "Return the one-line summary of file FILE, or current buffer if FILE is nil."
  (lm-with-file file
    (goto-char (point-min))
    (if (and (looking-at lm-header-prefix)
	     (progn (goto-char (match-end 0))
		    (looking-at "[^ ]+[ \t]+--+[ \t]+\\(.*\\)")))
	(let ((summary (match-string-no-properties 1)))
	  ;; Strip off -*- specifications.
	  (if (string-match "[ \t]*-\\*-.*-\\*-" summary)
	      (substring summary 0 (match-beginning 0))
	    summary)))))

(defun lm-crack-address (x)
  "Split up an email address X into full name and real email address.
The value is a cons of the form (FULLNAME . ADDRESS)."
  (cond ((string-match "\\(.+\\) [(<]\\(\\S-+@\\S-+\\)[>)]" x)
	 (cons (match-string 1 x)
	       (match-string 2 x)))
	((string-match "\\(\\S-+@\\S-+\\) [(<]\\(.*\\)[>)]" x)
	 (cons (match-string 2 x)
	       (match-string 1 x)))
	((string-match "\\S-+@\\S-+" x)
	 (cons nil x))
	(t
	 (cons x nil))))

(defun lm-authors (&optional file)
  "Return the author list of file FILE, or current buffer if FILE is nil.
Each element of the list is a cons; the car is the full name,
the cdr is an email address."
  (lm-with-file file
    (let ((authorlist (lm-header-multiline "author")))
      (mapcar #'lm-crack-address authorlist))))

(defun lm-maintainer (&optional file)
  "Return the maintainer of file FILE, or current buffer if FILE is nil.
The return value has the form (NAME . ADDRESS)."
  (lm-with-file file
    (let ((maint (lm-header "maintainer")))
      (if maint
	  (lm-crack-address maint)
	(car (lm-authors))))))

(defun lm-creation-date (&optional file)
  "Return the created date given in file FILE, or current buffer if FILE is nil."
  (lm-with-file file
    (lm-header "created")))

(defun lm-last-modified-date (&optional file iso-date)
  "Return the modify-date given in file FILE, or current buffer if FILE is nil.
ISO-DATE non-nil means return the date in ISO 8601 format."
  (lm-with-file file
    (when (progn (goto-char (point-min))
		 (re-search-forward
		  "\\$[I]d: [^ ]+ [^ ]+ \\([^/]+\\)/\\([^/]+\\)/\\([^ ]+\\) "
		  (lm-code-mark) t))
      (let ((dd (match-string 3))
	    (mm (match-string 2))
	    (yyyy (match-string 1)))
	(if iso-date
	    (format "%s-%s-%s" yyyy mm dd)
	  (format "%s %s %s"
		  dd
		  (nth (string-to-number mm)
		       '("" "Jan" "Feb" "Mar" "Apr" "May" "Jun"
			 "Jul" "Aug" "Sep" "Oct" "Nov" "Dec"))
		  yyyy))))))

(defun lm-version (&optional file)
  "Return the version listed in file FILE, or current buffer if FILE is nil.
This can be found in an RCS or SCCS header."
  (lm-with-file file
    (or (lm-header "version")
	(let ((header-max (lm-code-mark)))
	  (goto-char (point-min))
	  (cond
	   ;; Look for an RCS header
	   ((re-search-forward "\\$[I]d: [^ ]+ \\([^ ]+\\) " header-max t)
	    (match-string-no-properties 1))
	   ((re-search-forward "\\$Revision: +\\([^ ]+\\) " header-max t)
	    (match-string-no-properties 1))
	   ;; Look for an SCCS header
	   ((re-search-forward
	     (concat
	      "@(#)"
              (if buffer-file-name
                  (regexp-quote (file-name-nondirectory buffer-file-name))
                "[^\t\n]+")
	      "\t\\([012345679.]*\\)")
	     header-max t)
	    (match-string-no-properties 1)))))))

(defun lm-keywords (&optional file)
  "Return the keywords given in file FILE, or current buffer if FILE is nil.
The return is a `downcase'-ed string, or nil if no keywords
header.  Multi-line keywords are joined up with a space between
each line."
  (lm-with-file file
    (let ((keywords (lm-header-multiline "keywords")))
      (and keywords
	   (mapconcat #'downcase keywords " ")))))

(defun lm-keywords-list (&optional file)
  "Return list of keywords given in file FILE."
  (let ((keywords (lm-keywords file)))
    (if keywords
	(if (string-match-p "," keywords)
	    (split-string keywords ",[ \t\n]*" t "[ ]+")
	  (split-string keywords "[ \t\n]+" t "[ ]+")))))

(defvar finder-known-keywords)
(defun lm-keywords-finder-p (&optional file)
  "Return non-nil if any keywords in FILE are known to finder."
  (require 'finder)
  (let ((keys (lm-keywords-list file)))
    (catch 'keyword-found
      (while keys
	(if (assoc (intern (car keys)) finder-known-keywords)
	    (throw 'keyword-found t))
	(setq keys (cdr keys)))
      nil)))

(defun lm-adapted-by (&optional file)
  "Return the adapted-by names in file FILE, or current buffer if FILE is nil.
This is the name of the person who cleaned up this package for
distribution."
  (lm-with-file file
    (lm-header "adapted-by")))

(defun lm-commentary (&optional file)
  "Return the commentary in file FILE, or current buffer if FILE is nil.
Return the value as a string.  In the file, the commentary
section starts with the tag `Commentary' or `Documentation' and
ends just before the next section.  If the commentary section is
absent, return nil."
  (lm-with-file file
    (let ((start (lm-commentary-start)))
      (when start
        (buffer-substring-no-properties start (lm-commentary-end))))))

(defun lm-homepage (&optional file)
  "Return the homepage in file FILE, or current buffer if FILE is nil."
  (let ((page (lm-with-file file
		(lm-header "\\(?:x-\\)?\\(?:homepage\\|url\\)"))))
    (if (and page (string-match "^<.+>$" page))
	(substring page 1 -1)
      page)))

;;; Verification and synopses

(defun lm-insert-at-column (col &rest strings)
  "Insert, at column COL, list of STRINGS."
  (if (> (current-column) col) (insert "\n"))
  (move-to-column col t)
  (apply #'insert strings))

(defun lm-verify (&optional file showok verbose non-fsf-ok)
  "Check that the current buffer (or FILE if given) is in proper format.
If FILE is a directory, recurse on its files and generate a report in a
temporary buffer.  In that case, the optional argument SHOWOK
says display \"OK\" in temp buffer for files that have no problems.

Optional argument VERBOSE specifies verbosity level.
Optional argument NON-FSF-OK if non-nil means a non-FSF
copyright notice is allowed."
  (interactive (list nil nil t))
  (let* ((ret (and verbose "Ok"))
	 name)
    (if (and file (file-directory-p file))
	(setq ret
	      (with-temp-buffer
		(dolist (f (directory-files file nil "\\.el\\'")
			   (buffer-string))
		  (when (file-regular-p f)
		    (let ((status (lm-verify f)))
		      (insert f ":")
		      (if status
			  (lm-insert-at-column lm-comment-column status
					       "\n")
			(if showok
			    (lm-insert-at-column lm-comment-column
						 "OK\n"))))))))
      (lm-with-file file
	(setq name (lm-get-package-name))
	(setq ret
	      (cond
	       ((null name)
		"Can't find package name")
	       ((not (lm-authors))
		"`Author:' tag missing")
	       ((not (lm-maintainer))
		"`Maintainer:' tag missing")
	       ((not (lm-summary))
		"Can't find the one-line summary description")
	       ((not (lm-keywords))
		"`Keywords:' tag missing")
	       ((not (lm-keywords-finder-p))
		"`Keywords:' has no valid finder keywords (see `finder-known-keywords')")
	       ((not (lm-commentary-mark))
		"Can't find a `Commentary' section marker")
	       ((not (lm-history-mark))
		"Can't find a `History' section marker")
	       ((not (lm-code-mark))
		"Can't find a `Code' section marker")
	       ((progn
		  (goto-char (point-max))
		  (not
		   (re-search-backward
		    (concat "^;;;[ \t]+" name "[ \t]+ends here[ \t]*$"
			    "\\|^;;;[ \t]+ End of file[ \t]+" name)
		    nil t)))
		"Can't find the footer line")
	       ((not (and (lm-copyright-mark) (lm-crack-copyright)))
		"Can't find a valid copyright notice")
	       ((not (or non-fsf-ok
			 (string-match "Free Software Foundation"
				       (car (lm-crack-copyright)))))
		"Copyright holder is not the Free Software Foundation")
	       (t
		ret)))))
    (if verbose
	(message "%s" ret))
    ret))

(defun lm-synopsis (&optional file showall)
  "Generate a synopsis listing for the buffer or the given FILE if given.
If FILE is a directory, recurse on its files and generate a report in
a temporary buffer.  If SHOWALL is non-nil, also generate a line for files
which do not include a recognizable synopsis."
  (interactive
   (list
    (read-file-name "Synopsis for (file or dir): ")))

  (if (and file (file-directory-p file))
      (with-output-to-temp-buffer "*Synopsis*"
        (set-buffer standard-output)
        (dolist (f (directory-files file nil ".*\\.el\\'"))
          (let ((syn (lm-synopsis (expand-file-name f file))))
            (when (or syn showall)
              (insert f ":")
              (lm-insert-at-column lm-comment-column (or syn "NA") "\n")))))
    (save-excursion
      (let ((must-kill (and file (not (get-file-buffer file)))))
        (when file (find-file file))
        (prog1
            (if (called-interactively-p 'interactive)
                (message "%s" (lm-summary))
              (lm-summary))
          (when must-kill (kill-buffer (current-buffer))))))))

(defvar report-emacs-bug-address)

(defun lm-report-bug (topic)
  "Report a bug in the package currently being visited to its maintainer.
Prompts for bug subject TOPIC.  Leaves you in a mail buffer."
  (interactive "sBug Subject: ")
  (require 'emacsbug)
  (let ((package (lm-get-package-name))
	(addr (lm-maintainer))
	(version (lm-version)))
    (compose-mail (if addr
		      (concat (car addr) " <" (cdr addr) ">")
		    report-emacs-bug-address)
		  topic)
    (goto-char (point-max))
    (insert "\nIn " package)
    (if version
	(insert " version " version))
    (newline 2)
    (message "%s"
     (substitute-command-keys "Type \\[mail-send] to send bug report."))))

(provide 'lisp-mnt)

;;; lisp-mnt.el ends here