From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Ted Zlatanov Newsgroups: gmane.emacs.devel Subject: Re: [PATCH updated] Support for filesystem watching (inotify) Date: Tue, 07 Jun 2011 11:46:26 -0500 Organization: =?utf-8?B?0KLQtdC+0LTQvtGAINCX0LvQsNGC0LDQvdC+0LI=?= @ Cienfuegos Message-ID: <87boy9oahp.fsf@lifelogs.com> References: <201106040034.15598.ruediger@c-plusplus.de> <8762olmk6y.fsf@ambire.localdomain> <201106061825.25078.ruediger@c-plusplus.de> <871uz6hg1d.fsf@lifelogs.com> Reply-To: emacs-devel@gnu.org NNTP-Posting-Host: lo.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: dough.gmane.org 1307468173 14481 80.91.229.12 (7 Jun 2011 17:36:13 GMT) X-Complaints-To: usenet@dough.gmane.org NNTP-Posting-Date: Tue, 7 Jun 2011 17:36:13 +0000 (UTC) To: emacs-devel@gnu.org Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Tue Jun 07 19:36:10 2011 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([140.186.70.17]) by lo.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1QU0CH-000060-N2 for ged-emacs-devel@m.gmane.org; Tue, 07 Jun 2011 19:36:09 +0200 Original-Received: from localhost ([::1]:54277 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QU0CG-00086H-LM for ged-emacs-devel@m.gmane.org; Tue, 07 Jun 2011 13:36:08 -0400 Original-Received: from eggs.gnu.org ([140.186.70.92]:55898) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QTzQW-0003gy-QF for emacs-devel@gnu.org; Tue, 07 Jun 2011 12:46:49 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1QTzQV-0003cc-4M for emacs-devel@gnu.org; Tue, 07 Jun 2011 12:46:48 -0400 Original-Received: from lo.gmane.org ([80.91.229.12]:57348) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QTzQU-0003cP-Jw for emacs-devel@gnu.org; Tue, 07 Jun 2011 12:46:46 -0400 Original-Received: from list by lo.gmane.org with local (Exim 4.69) (envelope-from ) id 1QTzQR-0002JU-HS for emacs-devel@gnu.org; Tue, 07 Jun 2011 18:46:43 +0200 Original-Received: from 38.98.147.130 ([38.98.147.130]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Tue, 07 Jun 2011 18:46:43 +0200 Original-Received: from tzz by 38.98.147.130 with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Tue, 07 Jun 2011 18:46:43 +0200 X-Injected-Via-Gmane: http://gmane.org/ Mail-Followup-To: emacs-devel@gnu.org Original-Lines: 54 Original-X-Complaints-To: usenet@dough.gmane.org X-Gmane-NNTP-Posting-Host: 38.98.147.130 X-Face: bd.DQ~'29fIs`T_%O%C\g%6jW)yi[zuz6; d4V0`@y-~$#3P_Ng{@m+e4o<4P'#(_GJQ%TT= D}[Ep*b!\e,fBZ'j_+#"Ps?s2!4H2-Y"sx" Mail-Copies-To: never User-Agent: Gnus/5.110018 (No Gnus v0.18) Emacs/24.0.50 (gnu/linux) Cancel-Lock: sha1:Bu3xzGD1noFHB5etaveO7bCl9QM= X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6 (newer, 3) X-Received-From: 80.91.229.12 X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Original-Sender: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.devel:140267 Archived-At: On Tue, 07 Jun 2011 11:42:40 -0300 Stefan Monnier wrote: >>>> The problem is: How to implement the file-unwatch then? I need a way >>>> to identify each separate file-watch request. What would be the best >>>> way to do that? SM> How about letting file-watch return a "file-watcher" which you then need SM> to pass to file-unwatch? This "file-watcher" could be any kind of Elisp SM> data you find convenient for this. You may decide to provide no other SM> operation than file-unwatch, but you could also decide to provided SM> additional operations such as changing the callback (I'm not saying SM> that would necessarily be a good idea, tho, but maybe other operations SM> would be handy). >> (background: url-future.el is really a generic futures library, but the >> only expected use for it currently is in url-*.el) >> The "file-watcher" could derive from url-future, with the nice >> error-catching and accessor functions that come with it, plus it's >> protected from double-invocation. SM> That doesn't sound right to me. At least I'm having trouble figuring SM> out how to bend my mind such that this file-watcher matches (even SM> coarsely) the concept of a "future". In this case it's just a place to stash the callback, with protection against double invocation and error catching. Each instance holds a separate `file-watch' request. `file-unwatch' simply invokes the lambda to get the value to deregister. So `file-watch' would return (make-url-future :value (lambda () (unwatch file here)) :errorback (lambda (&rest d) (handle unwatch errors)) :callback (lambda (f) (arbitrary callback))) Which, in turn, can be used (say it's saved in `f'): (url-future-call f) ; funcall :value (url-future-value good) ; whatever (unwatch file here) returned (url-future-done-p f) ; true (url-future-completed-p f) ; true if no errors, plus :callback was called (url-future-errored-p f) ; true if errors, plus :errorback was called (url-future-call f) ; throws an error I think that's more convenient than a new special "file-watcher" type, especially since the "file-watcher" can be derived from "url-future" and inherit all the functions above under its own namespace, plus of course any fields it cares to define on top. The built-in support for callbacks and error callbacks is pretty nice too. Ted