From: Reiner Steib Date: Thu, 22 Nov 2007 20:50:16 +0000 (+0000) Subject: Move from ../gnus. Add hashcash payments to email. X-Git-Tag: emacs-pretest-23.0.90~9535 X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=47b1ca2636efd9a710091ac4f5d4970f516ab477;p=emacs.git Move from ../gnus. Add hashcash payments to email. --- diff --git a/lisp/ChangeLog b/lisp/ChangeLog index 2da23204b37..43ef38d73cd 100644 --- a/lisp/ChangeLog +++ b/lisp/ChangeLog @@ -1,3 +1,7 @@ +2007-11-22 Reiner Steib + + * mail/hashcash.el: Move from ../gnus. Add hashcash payments to email. + 2007-11-22 Glenn Morris * emulation/cua-base.el (x-clipboard-yank): Fix declaration. diff --git a/lisp/mail/hashcash.el b/lisp/mail/hashcash.el new file mode 100644 index 00000000000..737178b8218 --- /dev/null +++ b/lisp/mail/hashcash.el @@ -0,0 +1,370 @@ +;;; hashcash.el --- Add hashcash payments to email + +;; Copyright (C) 2003, 2004, 2005, 2007 Free Software Foundation + +;; Written by: Paul Foley (1997-2002) +;; Maintainer: Paul Foley +;; Keywords: mail, hashcash + +;; 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, 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; see the file COPYING. If not, write to the +;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, +;; Boston, MA 02110-1301, USA. + +;;; Commentary: + +;; The hashcash binary is at http://www.hashcash.org/. +;; +;; Call mail-add-payment to add a hashcash payment to a mail message +;; in the current buffer. +;; +;; Call mail-add-payment-async after writing the addresses but before +;; writing the mail to start calculating the hashcash payment +;; asynchronously. +;; +;; The easiest way to do this automatically for all outgoing mail +;; is to set `message-generate-hashcash' to t. If you want more +;; control, try the following hooks. +;; +;; To automatically add payments to all outgoing mail when sending: +;; (add-hook 'message-send-hook 'mail-add-payment) +;; +;; To start calculations automatically when addresses are prefilled: +;; (add-hook 'message-setup-hook 'mail-add-payment-async) +;; +;; To check whether calculations are done before sending: +;; (add-hook 'message-send-hook 'hashcash-wait-or-cancel) + +;;; Code: + +(defgroup hashcash nil + "Hashcash configuration." + :group 'mail) + +(defcustom hashcash-default-payment 20 + "*The default number of bits to pay to unknown users. +If this is zero, no payment header will be generated. +See `hashcash-payment-alist'." + :type 'integer + :group 'hashcash) + +(defcustom hashcash-payment-alist '() + "*An association list mapping email addresses to payment amounts. +Elements may consist of (ADDR AMOUNT) or (ADDR STRING AMOUNT), where +ADDR is the email address of the intended recipient and AMOUNT is +the value of hashcash payment to be made to that user. STRING, if +present, is the string to be hashed; if not present ADDR will be used." + :type '(repeat (choice (list :tag "Normal" + (string :name "Address") + (integer :name "Amount")) + (list :tag "Replace hash input" + (string :name "Address") + (string :name "Hash input") + (integer :name "Amount")))) + :group 'hashcash) + +(defcustom hashcash-default-accept-payment 20 + "*The default minimum number of bits to accept on incoming payments." + :type 'integer + :group 'hashcash) + +(defcustom hashcash-accept-resources `((,user-mail-address nil)) + "*An association list mapping hashcash resources to payment amounts. +Resources named here are to be accepted in incoming payments. If the +corresponding AMOUNT is NIL, the value of `hashcash-default-accept-payment' +is used instead." + :group 'hashcash) + +(defcustom hashcash-path (executable-find "hashcash") + "*The path to the hashcash binary." + :group 'hashcash) + +(defcustom hashcash-extra-generate-parameters nil + "*A list of parameter strings passed to `hashcash-path' when minting. +For example, you may want to set this to '(\"-Z2\") to reduce header length." + :type '(repeat string) + :group 'hashcash) + +(defcustom hashcash-double-spend-database "hashcash.db" + "*The path to the double-spending database." + :group 'hashcash) + +(defcustom hashcash-in-news nil + "*Specifies whether or not hashcash payments should be made to newsgroups." + :type 'boolean + :group 'hashcash) + +(defvar hashcash-process-alist nil + "Alist of asynchronous hashcash processes and buffers.") + +(require 'mail-utils) + +(eval-and-compile + (if (fboundp 'point-at-bol) + (defalias 'hashcash-point-at-bol 'point-at-bol) + (defalias 'hashcash-point-at-bol 'line-beginning-position)) + + (if (fboundp 'point-at-eol) + (defalias 'hashcash-point-at-eol 'point-at-eol) + (defalias 'hashcash-point-at-eol 'line-end-position))) + +(defun hashcash-strip-quoted-names (addr) + (setq addr (mail-strip-quoted-names addr)) + (if (and addr (string-match "\\`\\([^+@]+\\)\\+[^@]*\\(@.+\\)" addr)) + (concat (match-string 1 addr) (match-string 2 addr)) + addr)) + +(defun hashcash-token-substring () + (save-excursion + (let ((token "")) + (loop + (setq token + (concat token (buffer-substring (point) (hashcash-point-at-eol)))) + (goto-char (hashcash-point-at-eol)) + (forward-char 1) + (unless (looking-at "[ \t]") (return token)) + (while (looking-at "[ \t]") (forward-char 1)))))) + +(defun hashcash-payment-required (addr) + "Return the hashcash payment value required for the given address." + (let ((val (assoc addr hashcash-payment-alist))) + (or (nth 2 val) (nth 1 val) hashcash-default-payment))) + +(defun hashcash-payment-to (addr) + "Return the string with which hashcash payments should collide." + (let ((val (assoc addr hashcash-payment-alist))) + (or (nth 1 val) (nth 0 val) addr))) + +(defun hashcash-generate-payment (str val) + "Generate a hashcash payment by finding a VAL-bit collison on STR." + (if (and (> val 0) + hashcash-path) + (save-excursion + (set-buffer (get-buffer-create " *hashcash*")) + (erase-buffer) + (apply 'call-process hashcash-path nil t nil + "-m" "-q" "-b" (number-to-string val) str + hashcash-extra-generate-parameters) + (goto-char (point-min)) + (hashcash-token-substring)) + (error "No `hashcash' binary found"))) + +(defun hashcash-generate-payment-async (str val callback) + "Generate a hashcash payment by finding a VAL-bit collison on STR. +Return immediately. Call CALLBACK with process and result when ready." + (if (and (> val 0) + hashcash-path) + (let ((process (apply 'start-process "hashcash" nil + hashcash-path "-m" "-q" + "-b" (number-to-string val) str + hashcash-extra-generate-parameters))) + (setq hashcash-process-alist (cons + (cons process (current-buffer)) + hashcash-process-alist)) + (set-process-filter process `(lambda (process output) + (funcall ,callback process output)))) + (funcall callback nil nil))) + +(defun hashcash-check-payment (token str val) + "Check the validity of a hashcash payment." + (if hashcash-path + (zerop (call-process hashcash-path nil nil nil "-c" + "-d" "-f" hashcash-double-spend-database + "-b" (number-to-string val) + "-r" str + token)) + (progn + (message "No hashcash binary found") + (sleep-for 1) + nil))) + +(defun hashcash-version (token) + "Find the format version of a hashcash token." + ;; Version 1.2 looks like n:yymmdd:rrrrr:xxxxxxxxxxxxxxxx + ;; This carries its own version number embedded in the token, + ;; so no further format number changes should be necessary + ;; in the X-Payment header. + ;; + ;; Version 1.1 looks like yymmdd:rrrrr:xxxxxxxxxxxxxxxx + ;; You need to upgrade your hashcash binary. + ;; + ;; Version 1.0 looked like nnnnnrrrrrxxxxxxxxxxxxxxxx + ;; This is no longer supported. + (cond ((equal (aref token 1) ?:) 1.2) + ((equal (aref token 6) ?:) 1.1) + (t (error "Unknown hashcash format version")))) + +(defun hashcash-already-paid-p (recipient) + "Check for hashcash token to RECIPIENT in current buffer." + (save-excursion + (save-restriction + (message-narrow-to-headers-or-head) + (let ((token (message-fetch-field "x-hashcash")) + (case-fold-search t)) + (and (stringp token) + (string-match (regexp-quote recipient) token)))))) + +;;;###autoload +(defun hashcash-insert-payment (arg) + "Insert X-Payment and X-Hashcash headers with a payment for ARG" + (interactive "sPay to: ") + (unless (hashcash-already-paid-p arg) + (let ((pay (hashcash-generate-payment (hashcash-payment-to arg) + (hashcash-payment-required arg)))) + (when pay + (insert-before-markers "X-Hashcash: " pay "\n"))))) + +;;;###autoload +(defun hashcash-insert-payment-async (arg) + "Insert X-Payment and X-Hashcash headers with a payment for ARG +Only start calculation. Results are inserted when ready." + (interactive "sPay to: ") + (unless (hashcash-already-paid-p arg) + (hashcash-generate-payment-async + (hashcash-payment-to arg) + (hashcash-payment-required arg) + `(lambda (process payment) + (hashcash-insert-payment-async-2 ,(current-buffer) process payment))))) + +(defun hashcash-insert-payment-async-2 (buffer process pay) + (when (buffer-live-p buffer) + (with-current-buffer buffer + (save-excursion + (save-restriction + (setq hashcash-process-alist (delq + (assq process hashcash-process-alist) + hashcash-process-alist)) + (message-goto-eoh) + (when pay + (insert-before-markers "X-Hashcash: " pay))))))) + +(defun hashcash-cancel-async (&optional buffer) + "Delete any hashcash processes associated with BUFFER. +BUFFER defaults to the current buffer." + (interactive) + (unless buffer (setq buffer (current-buffer))) + (let (entry) + (while (setq entry (rassq buffer hashcash-process-alist)) + (delete-process (car entry)) + (setq hashcash-process-alist + (delq entry hashcash-process-alist))))) + +(defun hashcash-wait-async (&optional buffer) + "Wait for asynchronous hashcash processes in BUFFER to finish. +BUFFER defaults to the current buffer." + (interactive) + (unless buffer (setq buffer (current-buffer))) + (let (entry) + (while (setq entry (rassq buffer hashcash-process-alist)) + (accept-process-output (car entry))))) + +(defun hashcash-processes-running-p (buffer) + "Return non-nil if hashcash processes in BUFFER are still running." + (rassq buffer hashcash-process-alist)) + +(defun hashcash-wait-or-cancel () + "Ask user whether to wait for hashcash processes to finish." + (interactive) + (when (hashcash-processes-running-p (current-buffer)) + (if (y-or-n-p + "Hashcash process(es) still running; wait for them to finish? ") + (hashcash-wait-async) + (hashcash-cancel-async)))) + +;;;###autoload +(defun hashcash-verify-payment (token &optional resource amount) + "Verify a hashcash payment" + (let* ((split (split-string token ":")) + (key (if (< (hashcash-version token) 1.2) + (nth 1 split) + (case (string-to-number (nth 0 split)) + (0 (nth 2 split)) + (1 (nth 3 split)))))) + (cond ((null resource) + (let ((elt (assoc key hashcash-accept-resources))) + (and elt (hashcash-check-payment token (car elt) + (or (cadr elt) hashcash-default-accept-payment))))) + ((equal token key) + (hashcash-check-payment token resource + (or amount hashcash-default-accept-payment))) + (t nil)))) + +;;;###autoload +(defun mail-add-payment (&optional arg async) + "Add X-Payment: and X-Hashcash: headers with a hashcash payment +for each recipient address. Prefix arg sets default payment temporarily. +Set ASYNC to t to start asynchronous calculation. (See +`mail-add-payment-async')." + (interactive "P") + (let ((hashcash-default-payment (if arg (prefix-numeric-value arg) + hashcash-default-payment)) + (addrlist nil)) + (save-excursion + (save-restriction + (message-narrow-to-headers) + (let ((to (hashcash-strip-quoted-names (mail-fetch-field "To" nil t))) + (cc (hashcash-strip-quoted-names (mail-fetch-field "Cc" nil t))) + (ng (hashcash-strip-quoted-names (mail-fetch-field "Newsgroups" + nil t)))) + (when to + (setq addrlist (split-string to ",[ \t\n]*"))) + (when cc + (setq addrlist (nconc addrlist (split-string cc ",[ \t\n]*")))) + (when (and hashcash-in-news ng) + (setq addrlist (nconc addrlist (split-string ng ",[ \t\n]*"))))) + (when addrlist + (mapc (if async + #'hashcash-insert-payment-async + #'hashcash-insert-payment) + addrlist))))) + t) + +;;;###autoload +(defun mail-add-payment-async (&optional arg) + "Add X-Payment: and X-Hashcash: headers with a hashcash payment +for each recipient address. Prefix arg sets default payment temporarily. +Calculation is asynchronous." + (interactive "P") + (mail-add-payment arg t)) + +;;;###autoload +(defun mail-check-payment (&optional arg) + "Look for a valid X-Payment: or X-Hashcash: header. +Prefix arg sets default accept amount temporarily." + (interactive "P") + (let ((hashcash-default-accept-payment (if arg (prefix-numeric-value arg) + hashcash-default-accept-payment)) + (version (hashcash-version (hashcash-generate-payment "x" 1)))) + (save-excursion + (goto-char (point-min)) + (search-forward "\n\n") + (beginning-of-line) + (let ((end (point)) + (ok nil)) + (goto-char (point-min)) + (while (and (not ok) (search-forward "X-Payment: hashcash " end t)) + (let ((value (split-string (hashcash-token-substring) " "))) + (when (equal (car value) (number-to-string version)) + (setq ok (hashcash-verify-payment (cadr value)))))) + (goto-char (point-min)) + (while (and (not ok) (search-forward "X-Hashcash: " end t)) + (setq ok (hashcash-verify-payment (hashcash-token-substring)))) + (when ok + (message "Payment valid")) + ok)))) + +(provide 'hashcash) + +;;; arch-tag: 0e7fe983-a124-4392-9788-0dbcbd2c4d62