+++ /dev/null
-;;; hashcash.el --- Add hashcash payments to email
-
-;; Copyright (C) 2003, 2004, 2005, 2007 Free Software Foundation
-
-;; Written by: Paul Foley <mycroft@actrix.gen.nz> (1997-2002)
-;; Maintainer: Paul Foley <mycroft@actrix.gen.nz>
-;; 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
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