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emacs/lisp/mh-e/mh-xface.el
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;;; mh-xface.el --- MH-E X-Face and Face header field display -*- lexical-binding: t; -*-
;; Copyright (C) 2002-2003, 2005-2024 Free Software Foundation, Inc.
;; Author: Bill Wohler <wohler@newt.com>
;; Keywords: mail
;; See: mh-e.el
;; 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:
;;; Code:
(require 'mh-e)
(autoload 'mail-header-parse-address "mail-parse")
(autoload 'message-fetch-field "message")
(defvar mh-show-xface-function #'mh-face-display-function
"Determine at run time what function should be called to display X-Face.")
(make-obsolete-variable 'mh-show-xface-function nil "29.1")
(defvar mh-uncompface-executable (executable-find "uncompface"))
;;; X-Face Display
;;;###mh-autoload
(defun mh-show-xface ()
"Display X-Face."
(when (and window-system mh-show-use-xface-flag
(or mh-decode-mime-flag mh-mhl-format-file
mh-clean-message-header-flag))
(mh-face-display-function)))
(defun mh-face-display-function ()
"Display a Face, X-Face, or X-Image-URL header field.
If more than one of these are present, then the first one found
in this order is used."
(save-restriction
(goto-char (point-min))
(re-search-forward "\n\n" (point-max) t)
(narrow-to-region (point-min) (point))
(let* ((case-fold-search t)
(face (message-fetch-field "face" t))
(x-face (message-fetch-field "x-face" t))
(url (message-fetch-field "x-image-url" t))
raw type)
(cond (face (setq raw (mh-face-to-png face)
type 'png))
(x-face (setq raw (mh-uncompface x-face)
type 'pbm))
(url (setq type 'url))
(t (cl-multiple-value-setq (type raw)
(cl-values-list (mh-picon-get-image)))))
(when type
(goto-char (point-min))
(when (re-search-forward "^from:" (point-max) t)
(if (eq type 'url)
(mh-x-image-url-display url)
(insert-image (create-image
raw type t
:foreground
(face-foreground 'mh-show-xface nil t)
:background
(face-background 'mh-show-xface nil t))
" ")))))))
(defun mh-face-to-png (data)
"Convert base64 encoded DATA to png image."
(with-temp-buffer
(set-buffer-multibyte nil)
(insert data)
(ignore-errors (base64-decode-region (point-min) (point-max)))
(buffer-string)))
(defun mh-uncompface (data)
"Run DATA through `uncompface' to generate bitmap."
(with-temp-buffer
(set-buffer-multibyte nil)
(insert data)
(when (and mh-uncompface-executable
(equal (call-process-region (point-min) (point-max)
mh-uncompface-executable t '(t nil))
0))
(mh-icontopbm)
(buffer-string))))
(defun mh-icontopbm ()
"Elisp substitute for `icontopbm'."
(goto-char (point-min))
(let ((end (point-max)))
(while (re-search-forward "0x\\(..\\)\\(..\\)," nil t)
(save-excursion
(goto-char (point-max))
(insert (string-to-number (match-string 1) 16))
(insert (string-to-number (match-string 2) 16))))
(delete-region (point-min) end)
(goto-char (point-min))
(insert "P4\n48 48\n")))
;;; Picon Display
;; XXX: This should be customizable. As a side-effect of setting this
;; variable, arrange to reset mh-picon-existing-directory-list to 'unset.
(defvar mh-picon-directory-list
'("~/.picons" "~/.picons/users" "~/.picons/usenix" "~/.picons/news"
"~/.picons/domains" "~/.picons/misc"
"/usr/share/picons/" "/usr/share/picons/users" "/usr/share/picons/usenix"
"/usr/share/picons/news" "/usr/share/picons/domains"
"/usr/share/picons/misc")
"List of directories where picons reside.
The directories are searched for in the order they appear in the list.")
(defvar mh-picon-existing-directory-list 'unset
"List of directories to search in.")
(defvar mh-picon-cache (make-hash-table :test #'equal))
(defvar mh-picon-image-types
(cl-loop for type in '(xpm xbm gif)
when (ignore-errors
(image-type-available-p type))
collect type))
(autoload 'message-tokenize-header "sendmail")
(defun mh-picon-get-image ()
"Find the best possible match and return contents."
(mh-picon-set-directory-list)
(save-restriction
(let* ((from-field (ignore-errors (car (message-tokenize-header
(mh-get-header-field "from:")))))
(from (car (ignore-errors
(mail-header-parse-address from-field))))
(host (and from
(string-match "\\([^+]*\\)\\(\\+.*\\)?@\\(.*\\)" from)
(downcase (match-string 3 from))))
(user (and host (downcase (match-string 1 from))))
(canonical-address (format "%s@%s" user host))
(cached-value (gethash canonical-address mh-picon-cache))
(host-list (and host (delete "" (split-string host "\\.")))))
(cond
(cached-value cached-value)
((not host-list) nil)
(t
(let ((match
(cl-block loop
;; u@h search
(dolist (dir mh-picon-existing-directory-list)
(cl-loop for type in mh-picon-image-types
;; [path]user@host
for file1 = (format "%s/%s.%s"
dir canonical-address type)
when (file-exists-p file1)
do (cl-return-from loop file1)
;; [path]user
for file2 = (format "%s/%s.%s" dir user type)
when (file-exists-p file2)
do (cl-return-from loop file2)
;; [path]host
for file3 = (format "%s/%s.%s" dir host type)
when (file-exists-p file3)
do (cl-return-from loop file3)))
;; facedb search
;; Search order for user@foo.net:
;; [path]net/foo/user
;; [path]net/foo/user/face
;; [path]net/user
;; [path]net/user/face
;; [path]net/foo/unknown
;; [path]net/foo/unknown/face
;; [path]net/unknown
;; [path]net/unknown/face
(dolist (u (list user "unknown"))
(dolist (dir mh-picon-existing-directory-list)
(cl-loop for x on host-list by #'cdr
for y = (mh-picon-generate-path x u dir)
do (cl-loop for type in mh-picon-image-types
for z1 = (format "%s.%s" y type)
when (file-exists-p z1)
do (cl-return-from loop z1)
for z2 = (format "%s/face.%s"
y type)
when (file-exists-p z2)
do (cl-return-from loop z2))))))))
(setf (gethash canonical-address mh-picon-cache)
(mh-picon-file-contents match))))))))
(defun mh-picon-set-directory-list ()
"Update `mh-picon-existing-directory-list' if needed."
(when (eq mh-picon-existing-directory-list 'unset)
(setq mh-picon-existing-directory-list
(cl-loop for x in mh-picon-directory-list
when (file-directory-p x) collect x))))
(defun mh-picon-generate-path (host-list user directory)
"Generate the image file path.
HOST-LIST is the parsed host address of the email address, USER
the username and DIRECTORY is the directory relative to which the
path is generated."
(cl-loop with acc = ""
for elem in host-list
do (setq acc (format "%s/%s" elem acc))
finally return (format "%s/%s%s" directory acc user)))
(defun mh-picon-file-contents (file)
"Return details about FILE.
A list of consisting of a symbol for the type of the file and the
file contents as a string is returned. If FILE is nil, then both
elements of the list are nil."
(if (stringp file)
(with-temp-buffer
(set-buffer-multibyte nil)
(let ((type (and (string-match ".*\\.\\(...\\)$" file)
(intern (match-string 1 file)))))
(insert-file-contents-literally file)
(list type (buffer-string))))
(list nil nil)))
;;; X-Image-URL Display
(defvar mh-x-image-scaling-function
(cond ((executable-find "convert")
'mh-x-image-scale-with-convert)
((and (executable-find "anytopnm") (executable-find "pnmscale")
(executable-find "pnmtopng"))
'mh-x-image-scale-with-pnm)
(t 'ignore))
"Function to use to scale image to proper size.")
(defun mh-x-image-scale-with-pnm (input output)
"Scale image in INPUT file and write to OUTPUT file using pnm tools."
(let ((res (shell-command-to-string
(format "anytopnm < %s | pnmscale -xysize 96 48 | pnmtopng > %s"
input output))))
(unless (equal res "")
(delete-file output))))
(defun mh-x-image-scale-with-convert (input output)
"Scale image in INPUT file and write to OUTPUT file using ImageMagick."
(call-process "convert" nil nil nil "-geometry" "96x48" input output))
(defvar mh-wget-executable nil)
(defvar mh-wget-choice
(or (and (setq mh-wget-executable (executable-find "wget")) 'wget)
(and (setq mh-wget-executable (executable-find "fetch")) 'fetch)
(and (setq mh-wget-executable (executable-find "curl")) 'curl)))
(defvar mh-wget-option
(cdr (assoc mh-wget-choice '((curl . "-o") (fetch . "-o") (wget . "-O")))))
(defvar mh-x-image-temp-file nil)
(defvar mh-x-image-url nil)
(defvar mh-x-image-marker nil)
(defvar mh-x-image-url-cache-file nil)
(defun mh-x-image-url-display (url)
"Display image from location URL.
If the URL isn't present in the cache then it is fetched with wget."
(let* ((cache-filename (mh-x-image-url-cache-canonicalize url))
(state (mh-x-image-get-download-state cache-filename))
(marker (point-marker)))
(setq-local mh-x-image-marker marker)
(cond ((not (mh-x-image-url-sane-p url)))
((eq state 'ok)
(mh-x-image-display cache-filename marker))
((or (not mh-wget-executable)
(eq mh-x-image-scaling-function 'ignore)))
((eq state 'never))
((not mh-fetch-x-image-url)
(set-marker marker nil))
((eq state 'try-again)
(mh-x-image-set-download-state cache-filename nil)
(mh-x-image-url-fetch-image url cache-filename marker
'mh-x-image-scale-and-display))
((and (eq mh-fetch-x-image-url 'ask)
(not (y-or-n-p (format "Fetch %s? " url))))
(mh-x-image-set-download-state cache-filename 'never))
((eq state nil)
(mh-x-image-url-fetch-image url cache-filename marker
'mh-x-image-scale-and-display)))))
(defvar mh-x-image-cache-directory nil
"Directory where X-Image-URL images are cached.")
;;;###mh-autoload
(defun mh-set-x-image-cache-directory (directory)
"Set the DIRECTORY where X-Image-URL images are cached.
This is only done if `mh-x-image-cache-directory' is nil."
;; XXX This is the code that used to be in find-user-path. Is there
;; a good reason why the variable is set conditionally? Do we expect
;; the user to have set this variable directly?
(unless mh-x-image-cache-directory
(setq mh-x-image-cache-directory directory)))
(defun mh-x-image-url-cache-canonicalize (url)
"Canonicalize URL.
Replace the ?/ character with a ?! character and append .png.
Also replaces special characters with `url-hexify-string'
since not all characters, such as :, are valid within Windows
filenames. In addition, replaces * with %2a. See URL
`https://msdn.microsoft.com/library/default.asp?url=/library/en-us/shellcc/platform/shell/reference/ifaces/iitemnamelimits/GetValidCharacters.asp'."
(format "%s/%s.png" mh-x-image-cache-directory
(replace-regexp-in-string
"\\*" "%2a"
(url-hexify-string
(with-temp-buffer
(insert url)
(mh-replace-string "/" "!")
(buffer-string))))))
(defun mh-x-image-get-download-state (file)
"Check the state of FILE by following any symbolic links."
(unless (file-exists-p mh-x-image-cache-directory)
(call-process "mkdir" nil nil nil mh-x-image-cache-directory))
(cond ((file-symlink-p file)
(intern (file-name-nondirectory (file-chase-links file))))
((not (file-exists-p file)) nil)
(t 'ok)))
(defun mh-x-image-set-download-state (file data)
"Setup a symbolic link from FILE to DATA."
(if data
(make-symbolic-link (symbol-name data) file t)
(delete-file file)))
(defun mh-x-image-url-sane-p (url)
"Check if URL is something sensible."
(let ((len (length url)))
(cond ((> len 100) nil)
((and (>= len 5)
(equal (substring url 0 5) "http:") t))
((and (>= len 6)
(equal (substring url 0 6) "https:") t))
(t nil))))
(defun mh-x-image-display (image marker)
"Display IMAGE at MARKER."
(with-current-buffer (marker-buffer marker)
(let ((inhibit-read-only t)
(buffer-modified-flag (buffer-modified-p)))
(unwind-protect
(when (and (file-readable-p image) (not (file-symlink-p image))
(eq marker mh-x-image-marker))
(goto-char marker)
(insert-image (create-image image 'png)))
(set-buffer-modified-p buffer-modified-flag)))))
(defun mh-x-image-url-fetch-image (url cache-file marker sentinel)
"Fetch and display the image specified by URL.
After the image is fetched, it is stored in CACHE-FILE. It will
be displayed in a buffer and position specified by MARKER. The
actual display is carried out by the SENTINEL function."
(if mh-wget-executable
(let ((buffer (generate-new-buffer mh-temp-fetch-buffer))
(filename (make-temp-file "mhe-fetch")))
(with-current-buffer buffer
(setq-local mh-x-image-url-cache-file cache-file)
(setq-local mh-x-image-marker marker)
(setq-local mh-x-image-temp-file filename))
(set-process-sentinel
(start-process "*mh-x-image-url-fetch*" buffer
mh-wget-executable mh-wget-option filename url)
sentinel))
;; Temporary failure
(mh-x-image-set-download-state cache-file 'try-again)))
(defun mh-x-image-scale-and-display (process _change)
"When the wget PROCESS terminates scale and display image.
The argument CHANGE is ignored."
(when (eq (process-status process) 'exit)
(let (marker temp-file cache-filename wget-buffer)
(with-current-buffer (setq wget-buffer (process-buffer process))
(setq marker mh-x-image-marker
cache-filename mh-x-image-url-cache-file
temp-file mh-x-image-temp-file))
(cond
;; Check if we have `convert'
((eq mh-x-image-scaling-function 'ignore)
(message "The \"convert\" program is needed to display X-Image-URL")
(mh-x-image-set-download-state cache-filename 'try-again))
;; Scale fetched image
((and (funcall mh-x-image-scaling-function temp-file cache-filename)
nil))
;; Attempt to display image if we have it
((file-exists-p cache-filename)
(mh-x-image-display cache-filename marker))
;; We didn't find the image. Should we try to display it the next time?
(t (mh-x-image-set-download-state cache-filename 'try-again)))
(ignore-errors
(set-marker marker nil)
(delete-process process)
(kill-buffer wget-buffer)
(delete-file temp-file)))))
(provide 'mh-xface)
;; Local Variables:
;; sentence-end-double-space: nil
;; End:
;;; mh-xface.el ends here