summaryrefslogtreecommitdiff
path: root/lisp/gnus/nnoo.el
blob: 12df03c8b260020b93e577314f11c876c1da0f74 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
;;; nnoo.el --- OO Gnus Backends

;; Copyright (C) 1996-2012 Free Software Foundation, Inc.

;; Author: Lars Magne Ingebrigtsen <larsi@gnus.org>
;; Keywords: news

;; 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 <http://www.gnu.org/licenses/>.

;;; Commentary:

;;; Code:

(require 'nnheader)
(eval-when-compile (require 'cl))

(defvar nnoo-definition-alist nil)
(defvar nnoo-state-alist nil)
(defvar nnoo-parent-backend nil)

(defmacro defvoo (var init &optional doc &rest map)
  "The same as `defvar', only takes list of variables to MAP to."
  `(prog1
       ,(if doc
	    `(defvar ,var ,init ,(concat doc "\n\nThis is a Gnus server variable.  See Info node `(gnus)Select Methods'."))
	  `(defvar ,var ,init))
     (nnoo-define ',var ',map)))
(put 'defvoo 'lisp-indent-function 2)
(put 'defvoo 'edebug-form-spec '(var init &optional doc &rest map))

(defmacro deffoo (func args &rest forms)
  "The same as `defun', only register FUNC."
  `(prog1
       (defun ,func ,args ,@forms)
     (nnoo-register-function ',func)))
(put 'deffoo 'lisp-indent-function 2)
(put 'deffoo 'edebug-form-spec '(&define name lambda-list def-body))

(defun nnoo-register-function (func)
  (let ((funcs (nthcdr 3 (assoc (nnoo-backend func)
				nnoo-definition-alist))))
    (unless funcs
      (error "%s belongs to a backend that hasn't been declared" func))
    (setcar funcs (cons func (car funcs)))))

(defmacro nnoo-declare (backend &rest parents)
  `(eval-and-compile
     (if (assq ',backend nnoo-definition-alist)
	 (setcar (cdr (assq ',backend nnoo-definition-alist))
		 (mapcar 'list ',parents))
       (push (list ',backend
		   (mapcar 'list ',parents)
		   nil nil)
	     nnoo-definition-alist))
     (unless (assq ',backend nnoo-state-alist)
       (push (list ',backend "*internal-non-initialized-backend*")
	     nnoo-state-alist))))
(put 'nnoo-declare 'lisp-indent-function 1)

(defun nnoo-parents (backend)
  (nth 1 (assoc backend nnoo-definition-alist)))

(defun nnoo-variables (backend)
  (nth 2 (assoc backend nnoo-definition-alist)))

(defun nnoo-functions (backend)
  (nth 3 (assoc backend nnoo-definition-alist)))

(defmacro nnoo-import (backend &rest imports)
  `(nnoo-import-1 ',backend ',imports))
(put 'nnoo-import 'lisp-indent-function 1)

(defun nnoo-import-1 (backend imports)
  (let ((call-function
	 (if (symbolp (car imports)) (pop imports) 'nnoo-parent-function))
	imp functions function)
    (while (setq imp (pop imports))
      (setq functions
	    (or (cdr imp)
		(nnoo-functions (car imp))))
      (while functions
	(unless (fboundp
		 (setq function
		       (nnoo-symbol backend
				    (nnoo-rest-symbol (car functions)))))
	  (eval `(deffoo ,function (&rest args)
		   (,call-function ',backend ',(car functions) args))))
	(pop functions)))))

(defun nnoo-parent-function (backend function args)
  (let ((pbackend (nnoo-backend function))
	(nnoo-parent-backend backend))
    (nnoo-change-server pbackend
			(nnoo-current-server backend)
			(cdr (assq pbackend (nnoo-parents backend))))
    (prog1
	(apply function args)
      ;; Copy the changed variables back into the child.
      (let ((vars (cdr (assq pbackend (nnoo-parents backend)))))
	(while vars
	  (set (cadar vars) (symbol-value (caar vars)))
	  (setq vars (cdr vars)))))))

(defun nnoo-execute (backend function &rest args)
  "Execute FUNCTION on behalf of BACKEND."
  (let ((pbackend (nnoo-backend function))
	(nnoo-parent-backend backend))
    (nnoo-change-server pbackend
			(nnoo-current-server backend)
			(cdr (assq pbackend (nnoo-parents backend))))
    (prog1
	(apply function args)
      ;; Copy the changed variables back into the child.
      (let ((vars (cdr (assq pbackend (nnoo-parents backend)))))
	(while vars
	  (set (cadar vars) (symbol-value (caar vars)))
	  (setq vars (cdr vars)))))))

(defmacro nnoo-map-functions (backend &rest maps)
  `(nnoo-map-functions-1 ',backend ',maps))
(put 'nnoo-map-functions 'lisp-indent-function 1)

(defun nnoo-map-functions-1 (backend maps)
  (let (m margs i)
    (while (setq m (pop maps))
      (setq i 0
	    margs nil)
      (while (< i (length (cdr m)))
	(if (numberp (nth i (cdr m)))
	    (push `(nth ,i args) margs)
	  (push (nth i (cdr m)) margs))
	(incf i))
      (eval `(deffoo ,(nnoo-symbol backend (nnoo-rest-symbol (car m)))
		 (&rest args)
	       (nnoo-parent-function ',backend ',(car m)
				     ,(cons 'list (nreverse margs))))))))

(defun nnoo-backend (symbol)
  (string-match "^[^-]+-" (symbol-name symbol))
  (intern (substring (symbol-name symbol) 0 (1- (match-end 0)))))

(defun nnoo-rest-symbol (symbol)
  (string-match "^[^-]+-" (symbol-name symbol))
  (intern (substring (symbol-name symbol) (match-end 0))))

(defun nnoo-symbol (backend symbol)
  (intern (format "%s-%s" backend symbol)))

(defun nnoo-define (var map)
  (let* ((backend (nnoo-backend var))
	 (def (assq backend nnoo-definition-alist))
	 (parents (nth 1 def)))
    (unless def
      (error "%s belongs to a backend that hasn't been declared" var))
    (setcar (nthcdr 2 def)
	    (delq (assq var (nth 2 def)) (nth 2 def)))
    (setcar (nthcdr 2 def)
	    (cons (cons var (symbol-value var))
		  (nth 2 def)))
    (while map
      (nconc (assq (nnoo-backend (car map)) parents)
	     (list (list (pop map) var))))))

(defun nnoo-change-server (backend server defs)
  (let* ((bstate (cdr (assq backend nnoo-state-alist)))
	 (current (car bstate))
	 (parents (nnoo-parents backend))
	 (server (if nnoo-parent-backend
		     (format "%s+%s" nnoo-parent-backend server)
		   server))
	 (bvariables (nnoo-variables backend))
	 state def)
    ;; If we don't have a current state, we push an empty state
    ;; onto the alist.
    (unless bstate
      (push (setq bstate (list backend nil))
	    nnoo-state-alist)
      (pop bstate))
    (if (equal server current)
	t
      (nnoo-push-server backend current)
      (setq state (or (cdr (assoc server (cddr bstate)))
		      (nnoo-variables backend)))
      (while state
	(set (caar state) (cdar state))
	(pop state))
      (setcar bstate server)
      (unless (cdr (assoc server (cddr bstate)))
	(while (setq def (pop defs))
	  (unless (assq (car def) bvariables)
	    (nconc bvariables
		   (list (cons (car def) (and (boundp (car def))
					      (symbol-value (car def)))))))
	  (if (equal server "*internal-non-initialized-backend*")
	      (set (car def) (symbol-value (cadr def)))
	    (set (car def) (cadr def)))))
      (while parents
	(nnoo-change-server
	 (caar parents) (format "%s+%s" backend server)
	 (mapcar (lambda (def) (list (car def) (symbol-value (cadr def))))
		 (cdar parents)))
	(pop parents))))
  t)

(defun nnoo-push-server (backend current)
  (let ((bstate (assq backend nnoo-state-alist))
	(defs (nnoo-variables backend)))
    ;; Remove the old definition.
    (setcdr (cdr bstate) (delq (assoc current (cddr bstate)) (cddr bstate)))
    ;; If this is the first time we push the server (i. e., this is
    ;; the nil server), then we update the default values of
    ;; all the variables to reflect the current values.
    (when (equal current "*internal-non-initialized-backend*")
      (let ((defaults (nnoo-variables backend))
	    def)
	(while (setq def (pop defaults))
	  (setcdr def (symbol-value (car def))))))
    (let (state)
      (while defs
	(push (cons (caar defs) (symbol-value (caar defs)))
	      state)
	(pop defs))
      (nconc bstate (list (cons current state))))))

(defsubst nnoo-current-server-p (backend server)
  (equal (nnoo-current-server backend)
	 (if nnoo-parent-backend
	     (format "%s+%s" nnoo-parent-backend server)
	   server)))

(defun nnoo-current-server (backend)
  (nth 1 (assq backend nnoo-state-alist)))

(defun nnoo-close-server (backend &optional server)
  (unless server
    (setq server (nnoo-current-server backend)))
  (when server
    (let* ((bstate (cdr (assq backend nnoo-state-alist)))
	   (defs (assoc server (cdr bstate))))
      (when bstate
	(setcar bstate nil)
	(setcdr bstate (delq defs (cdr bstate)))
	(pop defs)
	(while defs
	  (set (car (pop defs)) nil)))))
  t)

(defun nnoo-close (backend)
  (setq nnoo-state-alist
	(delq (assq backend nnoo-state-alist)
	      nnoo-state-alist))
  t)

(defun nnoo-status-message (backend server)
  (nnheader-get-report backend))

(defun nnoo-server-opened (backend server)
  (and (nnoo-current-server-p backend server)
       nntp-server-buffer
       (buffer-name nntp-server-buffer)))

(defmacro nnoo-define-basics (backend)
  "Define `close-server', `server-opened' and `status-message'."
  `(eval-and-compile
     (nnoo-define-basics-1 ',backend)))

(defun nnoo-define-basics-1 (backend)
  (let ((functions '(close-server server-opened status-message)))
    (while functions
      (eval `(deffoo ,(nnoo-symbol backend (car functions))
		 (&optional server)
	       (,(nnoo-symbol 'nnoo (pop functions)) ',backend server)))))
  (eval `(deffoo ,(nnoo-symbol backend 'open-server)
	     (server &optional defs)
	   (nnoo-change-server ',backend server defs))))

(defmacro nnoo-define-skeleton (backend)
  "Define all required backend functions for BACKEND.
All functions will return nil and report an error."
  `(eval-and-compile
     (nnoo-define-skeleton-1 ',backend)))

(defun nnoo-define-skeleton-1 (backend)
  (let ((functions '(retrieve-headers
		     request-close request-article
		     request-group close-group
		     request-list request-post request-list-newsgroups))
	function fun)
    (while (setq function (pop functions))
      (when (not (fboundp (setq fun (nnoo-symbol backend function))))
	(eval `(deffoo ,fun
		   (&rest args)
		 (nnheader-report ',backend ,(format "%s-%s not implemented"
						     backend function))))))))

(defun nnoo-set (server &rest args)
  (let ((parents (nnoo-parents (car server)))
	(nnoo-parent-backend (car server)))
    (while parents
      (nnoo-change-server (caar parents)
			  (cadr server)
			  (cdar parents))
      (pop parents)))
  (nnoo-change-server (car server)
		      (cadr server) (cddr server))
  (while args
    (set (pop args) (pop args))))

(provide 'nnoo)

;;; nnoo.el ends here