From fa598825e414642e9092f93cde236052c7141827 Mon Sep 17 00:00:00 2001 From: Michael Olson Date: Sun, 27 Aug 2006 05:21:00 +0000 Subject: Include the tq.el file from Emacs 22 with EMMS, instead of re-implementing it in emms-player-mpd.el. darcs-hash:20060827052155-1bfb2-b2b47f20d03eaa85cecdf3c1805279edc59c68ee.gz --- tq.el | 171 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 171 insertions(+) create mode 100644 tq.el (limited to 'tq.el') diff --git a/tq.el b/tq.el new file mode 100644 index 0000000..1e1e143 --- /dev/null +++ b/tq.el @@ -0,0 +1,171 @@ +;;; tq.el --- utility to maintain a transaction queue + +;; Copyright (C) 1985, 1986, 1987, 1992, 2002, 2003, 2004, +;; 2005, 2006 Free Software Foundation, Inc. + +;; Author: Scott Draves +;; Maintainer: FSF +;; Adapted-By: ESR +;; Keywords: extensions + +;; 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., 51 Franklin Street, Fifth Floor, +;; Boston, MA 02110-1301, USA. + +;;; Commentary: + +;; This file manages receiving a stream asynchronously, parsing it +;; into transactions, and then calling the associated handler function +;; upon the completion of each transaction. + +;; Our basic structure is the queue/process/buffer triple. Each entry +;; of the queue part is a list of question, regexp, closure, and +;; function that is consed to the last element. + +;; A transaction queue may be created by calling `tq-create'. + +;; A request may be added to the queue by calling `tq-enqueue'. If +;; the `delay-question' argument is non-nil, we will wait to send the +;; question to the process until it has finished sending other input. +;; Otherwise, once a request is enqueued, we send the given question +;; immediately to the process. + +;; We then buffer bytes from the process until we see the regexp that +;; was provided in the call to `tq-enqueue'. Then we call the +;; provided function with the closure and the collected bytes. If we +;; have indicated that the question from the next transaction was not +;; sent immediately, send it at this point, awaiting the response. + +;;; Code: + +;;; Accessors + +;; This part looks like (queue . (process . buffer)) +(defun tq-queue (tq) (car tq)) +(defun tq-process (tq) (car (cdr tq))) +(defun tq-buffer (tq) (cdr (cdr tq))) + +;; The structure of `queue' is as follows +;; ((question regexp closure . fn) +;; ) +;; question: string to send to the process +(defun tq-queue-head-question (tq) (car (car (tq-queue tq)))) +;; regexp: regular expression that matches the end of a response from +;; the process +(defun tq-queue-head-regexp (tq) (car (cdr (car (tq-queue tq))))) +;; closure: additional data to pass to the function +(defun tq-queue-head-closure (tq) (car (cdr (cdr (car (tq-queue tq)))))) +;; fn: function to call upon receiving a complete response from the +;; process +(defun tq-queue-head-fn (tq) (cdr (cdr (cdr (car (tq-queue tq)))))) + +;; Determine whether queue is empty +(defun tq-queue-empty (tq) (not (tq-queue tq))) + +;;; Core functionality + +;;;###autoload +(defun tq-create (process) + "Create and return a transaction queue communicating with PROCESS. +PROCESS should be a subprocess capable of sending and receiving +streams of bytes. It may be a local process, or it may be connected +to a tcp server on another machine." + (let ((tq (cons nil (cons process + (generate-new-buffer + (concat " tq-temp-" + (process-name process))))))) + (set-process-filter process + `(lambda (proc string) + (tq-filter ',tq string))) + tq)) + +(defun tq-queue-add (tq question re closure fn) + (setcar tq (nconc (tq-queue tq) + (cons (cons question (cons re (cons closure fn))) nil))) + 'ok) + +(defun tq-queue-pop (tq) + (setcar tq (cdr (car tq))) + (let ((question (tq-queue-head-question tq))) + (when question + (process-send-string (tq-process tq) question))) + (null (car tq))) + +(defun tq-enqueue (tq question regexp closure fn &optional delay-question) + "Add a transaction to transaction queue TQ. +This sends the string QUESTION to the process that TQ communicates with. + +When the corresponding answer comes back, we call FN with two +arguments: CLOSURE, which may contain additional data that FN +needs, and the answer to the question. + +REGEXP is a regular expression to match the entire answer; +that's how we tell where the answer ends. + +If DELAY-QUESTION is non-nil, delay sending this question until +the process has finished replying to any previous questions. +This produces more reliable results with some processes." + (let ((sendp (or (not delay-question) + (not (tq-queue tq))))) + (tq-queue-add tq (unless sendp question) regexp closure fn) + (when sendp + (process-send-string (tq-process tq) question)))) + +(defun tq-close (tq) + "Shut down transaction queue TQ, terminating the process." + (delete-process (tq-process tq)) + (kill-buffer (tq-buffer tq))) + +(defun tq-filter (tq string) + "Append STRING to the TQ's buffer; then process the new data." + (let ((buffer (tq-buffer tq))) + (when (buffer-live-p buffer) + (with-current-buffer buffer + (goto-char (point-max)) + (insert string) + (tq-process-buffer tq))))) + +(defun tq-process-buffer (tq) + "Check TQ's buffer for the regexp at the head of the queue." + (let ((buffer (tq-buffer tq))) + (when (buffer-live-p buffer) + (set-buffer buffer) + (if (= 0 (buffer-size)) () + (if (tq-queue-empty tq) + (let ((buf (generate-new-buffer "*spurious*"))) + (copy-to-buffer buf (point-min) (point-max)) + (delete-region (point-min) (point)) + (pop-to-buffer buf nil) + (error "Spurious communication from process %s, see buffer %s" + (process-name (tq-process tq)) + (buffer-name buf))) + (goto-char (point-min)) + (if (re-search-forward (tq-queue-head-regexp tq) nil t) + (let ((answer (buffer-substring (point-min) (point)))) + (delete-region (point-min) (point)) + (unwind-protect + (condition-case nil + (funcall (tq-queue-head-fn tq) + (tq-queue-head-closure tq) + answer) + (error nil)) + (tq-queue-pop tq)) + (tq-process-buffer tq)))))))) + +(provide 'tq) + +;;; arch-tag: 65dea08c-4edd-4cde-83a5-e8a15b993b79 +;;; tq.el ends here -- cgit v1.2.3