From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on starla X-Spam-Level: X-Spam-Status: No, score=-1.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_PASS,SPF_PASS, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 Received: from nue.mailmanlists.eu (nue.mailmanlists.eu [IPv6:2a01:4f8:1c0c:6b10::1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by dcvr.yhbt.net (Postfix) with ESMTPS id 2A6011F405 for ; Fri, 2 Feb 2024 21:06:42 +0000 (UTC) Authentication-Results: dcvr.yhbt.net; dkim=pass (1024-bit key; secure) header.d=ml.ruby-lang.org header.i=@ml.ruby-lang.org header.a=rsa-sha256 header.s=mail header.b=Hh80O1en; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=ruby-lang.org header.i=@ruby-lang.org header.a=rsa-sha256 header.s=s1 header.b=OqZtu3Z+; dkim-atps=neutral Received: from nue.mailmanlists.eu (localhost [127.0.0.1]) by nue.mailmanlists.eu (Postfix) with ESMTP id 705D3826FC; Fri, 2 Feb 2024 21:06:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ml.ruby-lang.org; s=mail; t=1706907994; bh=H2/mET4PmLE9tLOAbUN5MXvvkolvEqGdZsxZAaoxBVc=; h=Date:References:To:Reply-To:Subject:List-Id:List-Archive: List-Help:List-Owner:List-Post:List-Subscribe:List-Unsubscribe: From:Cc:From; b=Hh80O1en9SGOz8r3b1g/jHEIJW/RzjanTVJy2CmPMAMVh5JdmXJsjOBNmEzN8FQo4 2bJlxAqx2Ak+iTk+uUfGexWfAS2fRXpHhX+K4juM0UkDL97+jrA4IBACFITG2y0Cqs fPIS2Pi/nEmxYlW395kAbnY5ouDPTM6NUWnSsed0= Received: from wrqvtvvn.outbound-mail.sendgrid.net (wrqvtvvn.outbound-mail.sendgrid.net [149.72.120.130]) by nue.mailmanlists.eu (Postfix) with ESMTPS id 4666E8269D for ; Fri, 2 Feb 2024 21:06:31 +0000 (UTC) Authentication-Results: nue.mailmanlists.eu; dkim=pass (2048-bit key; unprotected) header.d=ruby-lang.org header.i=@ruby-lang.org header.a=rsa-sha256 header.s=s1 header.b=OqZtu3Z+; dkim-atps=neutral DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ruby-lang.org; h=from:references:subject:mime-version:content-type: content-transfer-encoding:list-id:to:cc:content-type:from:subject:to; s=s1; bh=cWvujkp+PhDHYtnajyLK35ym7mFFojwe0p1PXvBhV2k=; b=OqZtu3Z+y+Mg7atpHjzc+5xJbz34PzFJIYsdHuu8aElSl5xlw3cATFGjUnUcTKliO11m TMclDqo4gU3Hxss5uW1xNzY5T3PAFemDy01reb7MGfiamYbYgXO4NEcn9+cPpZGWtFhr/0 z7Ywo0MzDT0SHisrO7SuxSTY76P3+WRLwQJevshjbn+iYNtUm8+i+ex9qx442xo5SBEdKl PZYU/i+YFGtoIRQ+X1y4U3Q7l7jdCj17+ieip8NxtKP0VHAgbNBo+7g/4TxL69sq1r/k6K r3rYdAaG/8YE+wJdSEeb/HCrPpySfon+RgNyy9HfjZ1f7ZfGmyIjSKBuT50WwmgA== Received: by filterdrecv-655bd866f5-c4wvc with SMTP id filterdrecv-655bd866f5-c4wvc-1-65BD5955-59 2024-02-02 21:06:29.916287208 +0000 UTC m=+1928972.740017125 Received: from herokuapp.com (unknown) by geopod-ismtpd-16 (SG) with ESMTP id 1BJjwn_hQ_uZFGc46K9gUA for ; Fri, 02 Feb 2024 21:06:29.837 +0000 (UTC) Date: Fri, 02 Feb 2024 21:06:29 +0000 (UTC) Message-ID: References: Mime-Version: 1.0 X-Redmine-Project: ruby-master X-Redmine-Issue-Tracker: Feature X-Redmine-Issue-Id: 20215 X-Redmine-Issue-Author: ioquatix X-Redmine-Sender: Eregon X-Mailer: Redmine X-Redmine-Host: bugs.ruby-lang.org X-Redmine-Site: Ruby Issue Tracking System X-Auto-Response-Suppress: All Auto-Submitted: auto-generated X-Redmine-MailingListIntegration-Message-Ids: 93118 X-SG-EID: =?us-ascii?Q?DvL3W2Xo+Vk=2FeUn3F50L=2FNc8u9NqZCnbE0mXZHiyye4R1YZg=2FtAFc0SAFzpcS=2F?= =?us-ascii?Q?Zcr7BqPN=2FYCcMZBMITNeIci9STxYay0JAJWPbek?= =?us-ascii?Q?rFR+qUdAzMIPFJD5TrbdYXschV1IOY65mj2Kzdn?= =?us-ascii?Q?3O4XBjeAaUOQEga95nSArBTgg2d7jrGkolBDRX2?= =?us-ascii?Q?rYcroKlNa7FzEyjwI=2FMqspzIgipVsyXBS0fgoF3?= =?us-ascii?Q?n4VCrj7OEMMwqOnLqk9vPh7MWxeY6W74vK2dgOw?= =?us-ascii?Q?A=2FQ4h7F+8x0nZeimEDJzw=3D=3D?= To: ruby-core@ml.ruby-lang.org X-Entity-ID: b/2+PoftWZ6GuOu3b0IycA== Message-ID-Hash: P55WIVURK25PFK44GME7ERXKV6QSTLSY X-Message-ID-Hash: P55WIVURK25PFK44GME7ERXKV6QSTLSY X-MailFrom: bounces+313651-b711-ruby-core=ml.ruby-lang.org@em5188.ruby-lang.org X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header X-Mailman-Version: 3.3.3 Precedence: list Reply-To: Ruby developers Subject: [ruby-core:116561] [Ruby master Feature#20215] Introduce `IO#readable?` List-Id: Ruby developers Archived-At: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: From: "Eregon (Benoit Daloze) via ruby-core" Cc: "Eregon (Benoit Daloze)" Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Issue #20215 has been updated by Eregon (Benoit Daloze). Would `io.wait_readable(0)` work instead? If not, why not? ---------------------------------------- Feature #20215: Introduce `IO#readable?` https://bugs.ruby-lang.org/issues/20215#change-106578 * Author: ioquatix (Samuel Williams) * Status: Open * Priority: Normal ---------------------------------------- There are some cases where, as an optimisation, it's useful to know whether more data is potentially available. We already have `IO#eof?` but the problem with using `IO#eof?` is that it can block indefinitely for sockets. Therefore, code which uses `IO#eof?` to determine if there is potentially more data, may hang. ```ruby def make_request(path = "/") client = connect_remote_host # HTTP/1.0 request: client.write("GET #{path} HTTP/1.0\r\n\r\n") # Read response client.gets("\r\n") # => "HTTP/1.0 200 OK\r\n" # Assuming connection close, there are two things the server can do: # 1. peer.close # 2. peer.write(...); peer.close if client.eof? # <--- Can hang here! puts "Connection closed" # Avoid yielding as we know there definitely won't be any data. else puts "Connection open, data may be available..." # There might be data available, so yield. yield(client) end ensure client&.close end make_request do |client| puts client.read # <--- Prefer to wait here. end ``` The proposed `IO#readable?` is similar to `IO#eof?` but rather than blocking, would simply return false. The expectation is the user will subsequently call `read` which may then wait. The proposed implementation would look something like this: ```ruby class IO def readable? !self.closed? end end class BasicSocket # Is it likely that the socket is still connected? # May return false positive, but won't return false negative. def readable? return false unless super # If we can wait for the socket to become readable, we know that the socket may still be open. result = self.recv_nonblock(1, MSG_PEEK, exception: false) # No data was available - newer Ruby can return nil instead of empty string: return false if result.nil? # Either there was some data available, or we can wait to see if there is data avaialble. return !result.empty? || result == :wait_readable rescue Errno::ECONNRESET # This might be thrown by recv_nonblock. return false end end ``` For `IO` itself, when there is buffered data, `readable?` would also return true immediately, similar to `eof?`. This is not shown in the above implementation as I'm not sure if there is any Ruby method which exposes "there is buffered data". -- https://bugs.ruby-lang.org/ ______________________________________________ ruby-core mailing list -- ruby-core@ml.ruby-lang.org To unsubscribe send an email to ruby-core-leave@ml.ruby-lang.org ruby-core info -- https://ml.ruby-lang.org/mailman3/postorius/lists/ruby-core.ml.ruby-lang.org/