From: Stefan Kangas <stefankangas@gmail.com>
Date: Tue, 11 Feb 2025 17:49:25 +0000 (+0100)
Subject: Move hashcash.el to lisp/obsolete
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=448f2cefc50333b13dff400e13e71c0eace530f8;p=emacs.git

Move hashcash.el to lisp/obsolete

* lisp/mail/hashcash.el: Move from here...
* lisp/obsolete/hashcash.el: ...to here.  (Bug#76195)

(cherry picked from commit 074b32d53f7a8c590895d49faf0f157aa800544e)
---

diff --git a/lisp/mail/hashcash.el b/lisp/mail/hashcash.el
deleted file mode 100644
index fac336bb6cc..00000000000
--- a/lisp/mail/hashcash.el
+++ /dev/null
@@ -1,372 +0,0 @@
-;;; hashcash.el --- Add hashcash payments to email  -*- lexical-binding:t -*-
-
-;; Copyright (C) 2003-2025 Free Software Foundation, Inc.
-
-;; Written by: Paul Foley <mycroft@actrix.gen.nz> (1997-2002)
-;; Maintainer: emacs-devel@gnu.org
-;; 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 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:
-
-;; 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 `opportunistic' or 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)
-;;
-;; For more information, see Info node `(gnus) Hashcash'.
-
-;;; Code:
-
-(eval-when-compile (require 'cl-lib))
-
-(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 'natnum)
-
-(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")))))
-
-(defcustom hashcash-default-accept-payment 20
-  "The default minimum number of bits to accept on incoming payments."
-  :type 'natnum)
-
-(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."
-  :type 'alist)
-
-(define-obsolete-variable-alias 'hashcash-path 'hashcash-program "24.4")
-(defcustom hashcash-program "hashcash"
-  "The name of the hashcash executable.
-If this is not in your PATH, specify an absolute file name.
-
-See also `message-generate-hashcash'."
-  :type '(choice (const nil) file))
-
-(defcustom hashcash-extra-generate-parameters '("-Z2")
-  "A list of parameter strings passed to `hashcash-program' when minting.
-For example, on very old hardware, you may want to set this
-to (\"-Z0\") to disable compression."
-  :type '(repeat string)
-  :version "29.1")
-
-(defcustom hashcash-double-spend-database "hashcash.db"
-  "The name of the double-spending database file."
-  :type 'file)
-
-(defcustom hashcash-in-news nil
-  "Specifies whether or not hashcash payments should be made to newsgroups."
-  :type 'boolean)
-
-(defvar hashcash-process-alist nil
-  "Alist of asynchronous hashcash processes and buffers.")
-
-(require 'mail-utils)
-
-(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))
-
-(declare-function message-narrow-to-headers-or-head "message" ())
-(declare-function message-fetch-field "message" (header &optional not-all))
-(declare-function message-goto-eoh "message" (&optional interactive))
-(declare-function message-narrow-to-headers "message" ())
-
-(defun hashcash-token-substring ()
-  (save-excursion
-    (let ((token ""))
-      (cl-loop
-	(setq token
-          (concat token (buffer-substring (point) (line-end-position))))
-        (goto-char (line-end-position))
-	(forward-char 1)
-	(unless (looking-at "[ \t]") (cl-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 collision on STR."
-  (if (and (> val 0)
-	   hashcash-program)
-      (with-current-buffer (get-buffer-create " *hashcash*")
-	(erase-buffer)
-	(apply 'call-process hashcash-program 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 collision on STR.
-Return immediately.  Call CALLBACK with process and result when ready."
-  (if (and (> val 0)
-	   hashcash-program)
-      (let ((process (apply 'start-process "hashcash" nil
-			    hashcash-program "-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 callback))
-    (funcall callback nil nil)))
-
-(defun hashcash-check-payment (token str val)
-  "Check the validity of a hashcash payment."
-  (if hashcash-program
-      (zerop (call-process hashcash-program 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)
-     (let ((buf (current-buffer)))
-       (lambda (process payment)
-         (hashcash-insert-payment-async-2 buf 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) 1))))
-
-(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)
-		  (pcase (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)
-        (goto-char (point-max))
-	(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))))
-
-(define-obsolete-function-alias 'hashcash-point-at-bol #'line-beginning-position "28.1")
-(define-obsolete-function-alias 'hashcash-point-at-eol #'line-end-position "28.1")
-
-(provide 'hashcash)
-
-;;; hashcash.el ends here
diff --git a/lisp/obsolete/hashcash.el b/lisp/obsolete/hashcash.el
new file mode 100644
index 00000000000..fac336bb6cc
--- /dev/null
+++ b/lisp/obsolete/hashcash.el
@@ -0,0 +1,372 @@
+;;; hashcash.el --- Add hashcash payments to email  -*- lexical-binding:t -*-
+
+;; Copyright (C) 2003-2025 Free Software Foundation, Inc.
+
+;; Written by: Paul Foley <mycroft@actrix.gen.nz> (1997-2002)
+;; Maintainer: emacs-devel@gnu.org
+;; 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 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:
+
+;; 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 `opportunistic' or 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)
+;;
+;; For more information, see Info node `(gnus) Hashcash'.
+
+;;; Code:
+
+(eval-when-compile (require 'cl-lib))
+
+(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 'natnum)
+
+(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")))))
+
+(defcustom hashcash-default-accept-payment 20
+  "The default minimum number of bits to accept on incoming payments."
+  :type 'natnum)
+
+(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."
+  :type 'alist)
+
+(define-obsolete-variable-alias 'hashcash-path 'hashcash-program "24.4")
+(defcustom hashcash-program "hashcash"
+  "The name of the hashcash executable.
+If this is not in your PATH, specify an absolute file name.
+
+See also `message-generate-hashcash'."
+  :type '(choice (const nil) file))
+
+(defcustom hashcash-extra-generate-parameters '("-Z2")
+  "A list of parameter strings passed to `hashcash-program' when minting.
+For example, on very old hardware, you may want to set this
+to (\"-Z0\") to disable compression."
+  :type '(repeat string)
+  :version "29.1")
+
+(defcustom hashcash-double-spend-database "hashcash.db"
+  "The name of the double-spending database file."
+  :type 'file)
+
+(defcustom hashcash-in-news nil
+  "Specifies whether or not hashcash payments should be made to newsgroups."
+  :type 'boolean)
+
+(defvar hashcash-process-alist nil
+  "Alist of asynchronous hashcash processes and buffers.")
+
+(require 'mail-utils)
+
+(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))
+
+(declare-function message-narrow-to-headers-or-head "message" ())
+(declare-function message-fetch-field "message" (header &optional not-all))
+(declare-function message-goto-eoh "message" (&optional interactive))
+(declare-function message-narrow-to-headers "message" ())
+
+(defun hashcash-token-substring ()
+  (save-excursion
+    (let ((token ""))
+      (cl-loop
+	(setq token
+          (concat token (buffer-substring (point) (line-end-position))))
+        (goto-char (line-end-position))
+	(forward-char 1)
+	(unless (looking-at "[ \t]") (cl-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 collision on STR."
+  (if (and (> val 0)
+	   hashcash-program)
+      (with-current-buffer (get-buffer-create " *hashcash*")
+	(erase-buffer)
+	(apply 'call-process hashcash-program 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 collision on STR.
+Return immediately.  Call CALLBACK with process and result when ready."
+  (if (and (> val 0)
+	   hashcash-program)
+      (let ((process (apply 'start-process "hashcash" nil
+			    hashcash-program "-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 callback))
+    (funcall callback nil nil)))
+
+(defun hashcash-check-payment (token str val)
+  "Check the validity of a hashcash payment."
+  (if hashcash-program
+      (zerop (call-process hashcash-program 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)
+     (let ((buf (current-buffer)))
+       (lambda (process payment)
+         (hashcash-insert-payment-async-2 buf 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) 1))))
+
+(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)
+		  (pcase (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)
+        (goto-char (point-max))
+	(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))))
+
+(define-obsolete-function-alias 'hashcash-point-at-bol #'line-beginning-position "28.1")
+(define-obsolete-function-alias 'hashcash-point-at-eol #'line-end-position "28.1")
+
+(provide 'hashcash)
+
+;;; hashcash.el ends here