lisp/nnoo.el

   1 ;;; nnoo.el --- OO Gnus Backends
   2 ;; Copyright (C) 1996 Free Software Foundation, Inc.
   3
   4 ;; Author: Lars Magne Ingebrigtsen <larsi@ifi.uio.no>
   5 ;; Keywords: news
   6
   7 ;; This file is part of GNU Emacs.
   8
   9 ;; GNU Emacs is free software; you can redistribute it and/or modify
  10 ;; it under the terms of the GNU General Public License as published by
  11 ;; the Free Software Foundation; either version 2, or (at your option)
  12 ;; any later version.
  13
  14 ;; GNU Emacs is distributed in the hope that it will be useful,
  15 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  16 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17 ;; GNU General Public License for more details.
  18
  19 ;; You should have received a copy of the GNU General Public License
  20 ;; along with GNU Emacs; see the file COPYING.  If not, write to the
  21 ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  22 ;; Boston, MA 02111-1307, USA.
  23
  24 ;;; Commentary:
  25
  26 ;;; Code:
  27
  28 (eval-when-compile (require 'cl))
  29
  30 (defvar nnoo-definition-alist nil)
  31 (defvar nnoo-state-alist nil)
  32
  33 (defmacro defvoo (var init &optional doc &rest map)
  34   "The same as `defvar', only takes list of variables to MAP to."
  35   `(prog1
  36        ,(if doc
  37             `(defvar ,var ,init ,doc)
  38           `(defvar ,var ,init))
  39      (nnoo-define ',var ',map)))
  40 (put 'defvoo 'lisp-indent-function 2)
  41 (put 'defvoo 'lisp-indent-hook 2)
  42 (put 'defvoo 'edebug-form-spec '(var init &optional doc &rest map))
  43
  44 (defmacro deffoo (func args &rest forms)
  45   "The same as `defun', only register FUNC."
  46   `(prog1
  47        (defun ,func ,args ,@forms)
  48      (nnoo-register-function ',func)))
  49 (put 'deffoo 'lisp-indent-function 2)
  50 (put 'deffoo 'lisp-indent-hook 2)
  51 (put 'deffoo 'edebug-form-spec '(&define name lambda-list def-body))
  52
  53 (defun nnoo-register-function (func)
  54   (let ((funcs (nthcdr 3 (assoc (nnoo-backend func)
  55                                 nnoo-definition-alist))))
  56     (unless funcs
  57       (error "%s belongs to a backend that hasn't been declared" func))
  58     (setcar funcs (cons func (car funcs)))))
  59
  60 (defmacro nnoo-declare (backend &rest parents)
  61   `(eval-and-compile
  62      (push (list ',backend
  63                  (mapcar (lambda (p) (list p)) ',parents)
  64                  nil nil)
  65            nnoo-definition-alist)))
  66 (put 'nnoo-declare 'lisp-indent-function 1)
  67 (put 'nnoo-declare 'lisp-indent-hook 1)
  68
  69 (defun nnoo-parents (backend)
  70   (nth 1 (assoc backend nnoo-definition-alist)))
  71
  72 (defun nnoo-variables (backend)
  73   (nth 2 (assoc backend nnoo-definition-alist)))
  74
  75 (defun nnoo-functions (backend)
  76   (nth 3 (assoc backend nnoo-definition-alist)))
  77
  78 (defmacro nnoo-import (backend &rest imports)
  79   `(nnoo-import-1 ',backend ',imports))
  80 (put 'nnoo-import 'lisp-indent-function 1)
  81 (put 'nnoo-import 'lisp-indent-hook 1)
  82
  83 (defun nnoo-import-1 (backend imports)
  84   (let ((call-function
  85          (if (symbolp (car imports)) (pop imports) 'nnoo-parent-function))
  86         imp functions function)
  87     (while (setq imp (pop imports))
  88       (setq functions
  89             (or (cdr imp)
  90                 (nnoo-functions (car imp))))
  91       (while functions
  92         (unless (fboundp (setq function
  93                                (nnoo-symbol backend (nnoo-rest-symbol
  94                                                          (car functions)))))
  95           (eval `(deffoo ,function (&rest args)
  96                    (,call-function ',backend ',(car functions) args))))
  97         (pop functions)))))
  98
  99 (defun nnoo-parent-function (backend function args)
 100   (let* ((pbackend (nnoo-backend function)))
 101     (nnoo-change-server pbackend (nnoo-current-server backend)
 102                         (cdr (assq pbackend (nnoo-parents backend))))
 103     (apply function args)))
 104
 105 (defun nnoo-execute (backend function &rest args)
 106   "Execute FUNCTION on behalf of BACKEND."
 107   (let* ((pbackend (nnoo-backend function)))
 108     (nnoo-change-server pbackend (nnoo-current-server backend)
 109                         (cdr (assq pbackend (nnoo-parents backend))))
 110     (apply function args)))
 111
 112 (defmacro nnoo-map-functions (backend &rest maps)
 113   `(nnoo-map-functions-1 ',backend ',maps))
 114 (put 'nnoo-map-functions 'lisp-indent-function 1)
 115 (put 'nnoo-map-functions 'lisp-indent-hook 1)
 116
 117 (defun nnoo-map-functions-1 (backend maps)
 118   (let (m margs i)
 119     (while (setq m (pop maps))
 120       (setq i 0
 121             margs nil)
 122       (while (< i (length (cdr m)))
 123         (if (numberp (nth i (cdr m)))
 124             (push `(nth ,i args) margs)
 125           (push (nth i (cdr m)) margs))
 126         (incf i))
 127       (eval `(deffoo ,(nnoo-symbol backend (nnoo-rest-symbol (car m)))
 128                  (&rest args)
 129                (nnoo-parent-function ',backend ',(car m)
 130                                      ,(cons 'list (nreverse margs))))))))
 131
 132 (defun nnoo-backend (symbol)
 133   (string-match "^[^-]+-" (symbol-name symbol))
 134   (intern (substring (symbol-name symbol) 0 (1- (match-end 0)))))
 135
 136 (defun nnoo-rest-symbol (symbol)
 137   (string-match "^[^-]+-" (symbol-name symbol))
 138   (intern (substring (symbol-name symbol) (match-end 0))))
 139
 140 (defun nnoo-symbol (backend symbol)
 141   (intern (format "%s-%s" backend symbol)))
 142
 143 (defun nnoo-define (var map)
 144   (let* ((backend (nnoo-backend var))
 145          (def (assq backend nnoo-definition-alist))
 146          (parents (nth 1 def)))
 147     (unless def
 148       (error "%s belongs to a backend that hasn't been declared." var))
 149     (setcar (nthcdr 2 def)
 150             (delq (assq var (nth 2 def)) (nth 2 def)))
 151     (setcar (nthcdr 2 def)
 152             (cons (cons var (symbol-value var))
 153                   (nth 2 def)))
 154     (while map
 155       (nconc (assq (nnoo-backend (car map)) parents)
 156              (list (list (pop map) var))))))
 157
 158 (defun nnoo-change-server (backend server defs)
 159   (let* ((bstate (cdr (assq backend nnoo-state-alist)))
 160          (sdefs (assq backend nnoo-definition-alist))
 161          (current (car bstate))
 162          (parents (nnoo-parents backend))
 163          state)
 164     (unless bstate
 165       (push (setq bstate (list backend nil))
 166             nnoo-state-alist)
 167       (pop bstate))
 168     (if (equal server current)
 169         t
 170       (nnoo-push-server backend current)
 171       (setq state (or (cdr (assoc server (cddr bstate)))
 172                       (nnoo-variables backend)))
 173       (while state
 174         (set (caar state) (cdar state))
 175         (pop state))
 176       (setcar bstate server)
 177       (unless (cdr (assoc server (cddr bstate)))
 178         (while defs
 179           (set (caar defs) (cadar defs))
 180           (pop defs)))
 181       (while parents
 182         (nnoo-change-server
 183          (caar parents) server
 184          (mapcar (lambda (def) (list (car def) (symbol-value (cadr def))))
 185                  (cdar parents)))
 186         (pop parents))))
 187   t)
 188
 189 (defun nnoo-push-server (backend current)
 190   (let ((bstate (assq backend nnoo-state-alist))
 191         (defs (nnoo-variables backend)))
 192     ;; Remove the old definition.
 193     (setcdr (cdr bstate) (delq (assoc current (cddr bstate)) (cddr bstate)))
 194     (let (state)
 195       (while defs
 196         (push (cons (caar defs) (symbol-value (caar defs)))
 197               state)
 198         (pop defs))
 199       (nconc bstate (list (cons current state))))))
 200
 201 (defun nnoo-current-server-p (backend server)
 202   (equal (nnoo-current-server backend) server))
 203
 204 (defun nnoo-current-server (backend)
 205   (nth 1 (assq backend nnoo-state-alist)))
 206
 207 (defun nnoo-close-server (backend &optional server)
 208   (unless server
 209     (setq server (nnoo-current-server backend)))
 210   (when server
 211     (let* ((bstate (cdr (assq backend nnoo-state-alist)))
 212            (defs (assoc server (cdr bstate))))
 213       (when bstate
 214         (setcar bstate nil)
 215         (setcdr bstate (delq defs (cdr bstate)))
 216         (pop defs)
 217         (while defs
 218           (set (car (pop defs)) nil)))))
 219   t)
 220
 221 (defun nnoo-close (backend)
 222   (setq nnoo-state-alist
 223         (delq (assq backend nnoo-state-alist)
 224               nnoo-state-alist))
 225   t)
 226
 227 (defun nnoo-status-message (backend server)
 228   (nnheader-get-report backend))
 229
 230 (defun nnoo-server-opened (backend server)
 231   (and (nnoo-current-server-p backend server)
 232        nntp-server-buffer
 233        (buffer-name nntp-server-buffer)))
 234
 235 (defmacro nnoo-define-basics (backend)
 236   `(eval-and-compile
 237      (nnoo-define-basics-1 ',backend)))
 238
 239 (defun nnoo-define-basics-1 (backend)
 240   (let ((functions '(close-server server-opened status-message)))
 241     (while functions
 242       (eval `(deffoo ,(nnoo-symbol backend (car functions))
 243                  (&optional server)
 244                (,(nnoo-symbol 'nnoo (pop functions)) ',backend server)))))
 245   (eval `(deffoo ,(nnoo-symbol backend 'open-server)
 246              (server &optional defs)
 247            (nnoo-change-server ',backend server defs))))
 248
 249 (provide 'nnoo)
 250
 251 ;;; nnoo.el ends here.