Initial revision

1 files changed, 279 insertions, 0 deletions

diff --git a/lisp/gnus/nnoo.el b/lisp/gnus/nnoo.el
new file mode 100644
index 00000000000..c768d04f6d2
--- /dev/null
+++ b/lisp/gnus/nnoo.el
@@ -0,0 +1,279 @@
+;;; nnoo.el --- OO Gnus Backends
+;; Copyright (C) 1996,97 Free Software Foundation, Inc.
+
+;; Author: Lars Magne Ingebrigtsen <larsi@ifi.uio.no>
+;; 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 2, 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., 59 Temple Place - Suite 330,
+;; Boston, MA 02111-1307, USA.
+
+;;; Commentary:
+
+;;; Code:
+
+(require 'nnheader)
+(require 'cl)
+
+(defvar nnoo-definition-alist nil)
+(defvar nnoo-state-alist 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 ,doc)
+	  `(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
+     (push (list ',backend
+		 (mapcar (lambda (p) (list p)) ',parents)
+		 nil nil)
+	   nnoo-definition-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-change-server pbackend (nnoo-current-server backend)
+			(cdr (assq pbackend (nnoo-parents backend))))
+    (apply function args)))
+
+(defun nnoo-execute (backend function &rest args)
+  "Execute FUNCTION on behalf of BACKEND."
+  (let* ((pbackend (nnoo-backend function)))
+    (nnoo-change-server pbackend (nnoo-current-server backend)
+			(cdr (assq pbackend (nnoo-parents backend))))
+    (apply function args)))
+
+(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))
+	 (bvariables (nnoo-variables backend))
+	 state def)
+    (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)))))))
+	  (set (car def) (cadr def))))
+      (while parents
+	(nnoo-change-server
+	 (caar parents) 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) 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))))))))
+(provide 'nnoo)
+
+;;; nnoo.el ends here.