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124 lines
4.2 KiB
EmacsLisp
124 lines
4.2 KiB
EmacsLisp
;;; tq.el --- utility to maintain a transaction queue
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;; Copyright (C) 1985, 1986, 1987, 1992 Free Software Foundation, Inc.
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;; Author: Scott Draves <spot@cs.cmu.edu>
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;; Maintainer: FSF
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;; Adapted-By: ESR
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;; Keywords: extensions
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;; This file is part of GNU Emacs.
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;; GNU Emacs is free software; you can redistribute it and/or modify
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;; it under the terms of the GNU General Public License as published by
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;; the Free Software Foundation; either version 2, or (at your option)
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;; any later version.
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;; GNU Emacs is distributed in the hope that it will be useful,
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;; but WITHOUT ANY WARRANTY; without even the implied warranty of
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;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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;; GNU General Public License for more details.
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;; You should have received a copy of the GNU General Public License
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;; along with GNU Emacs; see the file COPYING. If not, write to the
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;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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;; Boston, MA 02111-1307, USA.
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;;; Commentary:
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;; manages receiving a stream asynchronously,
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;; parsing it into transactions, and then calling
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;; handler functions
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;; Our basic structure is the queue/process/buffer triple. Each entry
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;; of the queue is a regexp/closure/function triple. We buffer
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;; bytes from the process until we see the regexp at the head of the
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;; queue. Then we call the function with the closure and the
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;; collected bytes.
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;;; Code:
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;;;###autoload
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(defun tq-create (process)
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"Create and return a transaction queue communicating with PROCESS.
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PROCESS should be a subprocess capable of sending and receiving
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streams of bytes. It may be a local process, or it may be connected
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to a tcp server on another machine."
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(let ((tq (cons nil (cons process
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(generate-new-buffer
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(concat " tq-temp-"
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(process-name process)))))))
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(set-process-filter process
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(`(lambda (proc string)
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(tq-filter '(, tq) string))))
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tq))
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;;; accessors
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(defun tq-queue (tq) (car tq))
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(defun tq-process (tq) (car (cdr tq)))
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(defun tq-buffer (tq) (cdr (cdr tq)))
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(defun tq-queue-add (tq re closure fn)
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(setcar tq (nconc (tq-queue tq)
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(cons (cons re (cons closure fn)) nil)))
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'ok)
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(defun tq-queue-head-regexp (tq) (car (car (tq-queue tq))))
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(defun tq-queue-head-fn (tq) (cdr (cdr (car (tq-queue tq)))))
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(defun tq-queue-head-closure (tq) (car (cdr (car (tq-queue tq)))))
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(defun tq-queue-empty (tq) (not (tq-queue tq)))
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(defun tq-queue-pop (tq) (setcar tq (cdr (car tq))) (null (car tq)))
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;;; must add to queue before sending!
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(defun tq-enqueue (tq question regexp closure fn)
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"Add a transaction to transaction queue TQ.
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This sends the string QUESTION to the process that TQ communicates with.
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When the corresponding answer comes back, we call FN
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with two arguments: CLOSURE, and the answer to the question.
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REGEXP is a regular expression to match the entire answer;
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that's how we tell where the answer ends."
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(tq-queue-add tq regexp closure fn)
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(process-send-string (tq-process tq) question))
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(defun tq-close (tq)
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"Shut down transaction queue TQ, terminating the process."
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(delete-process (tq-process tq))
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(kill-buffer (tq-buffer tq)))
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(defun tq-filter (tq string)
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"Append STRING to the TQ's buffer; then process the new data."
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(with-current-buffer (tq-buffer tq)
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(goto-char (point-max))
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(insert string)
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(tq-process-buffer tq)))
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(defun tq-process-buffer (tq)
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"Check TQ's buffer for the regexp at the head of the queue."
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(set-buffer (tq-buffer tq))
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(if (= 0 (buffer-size)) ()
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(if (tq-queue-empty tq)
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(let ((buf (generate-new-buffer "*spurious*")))
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(copy-to-buffer buf (point-min) (point-max))
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(delete-region (point-min) (point))
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(pop-to-buffer buf nil)
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(error "Spurious communication from process %s, see buffer %s"
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(process-name (tq-process tq))
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(buffer-name buf)))
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(goto-char (point-min))
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(if (re-search-forward (tq-queue-head-regexp tq) nil t)
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(let ((answer (buffer-substring (point-min) (point))))
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(delete-region (point-min) (point))
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(unwind-protect
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(condition-case nil
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(funcall (tq-queue-head-fn tq)
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(tq-queue-head-closure tq)
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answer)
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(error nil))
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(tq-queue-pop tq))
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(tq-process-buffer tq))))))
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(provide 'tq)
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;;; tq.el ends here
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