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=0.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,MAILING_LIST_MULTI,RCVD_IN_BL_SPAMCOP_NET,SPF_HELO_PASS, SPF_PASS autolearn=no autolearn_force=no version=3.4.6 Received: from nue.mailmanlists.eu (nue.mailmanlists.eu [94.130.110.93]) (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 1990B1F44D for ; Wed, 17 Apr 2024 00:07:40 +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=AAgAc4QA; 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=aKCY782p; dkim-atps=neutral Received: from nue.mailmanlists.eu (localhost [127.0.0.1]) by nue.mailmanlists.eu (Postfix) with ESMTP id DFD9F84347; Wed, 17 Apr 2024 00:07:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ml.ruby-lang.org; s=mail; t=1713312449; bh=RQcKIeeD51MppyW16gZ0WL6nrb2e631OgA/9+Rocjrc=; 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=AAgAc4QAmH6FmJYQIQkmV8jw0w+xtZ+tlOdDGI7rFT/52OcLu+j3lB9S1fYrJvhtB deN+8vYUaxzjLRQaODNASFbHr+QEbfYX9CBxn8sf3mUwFlCGZSP5LiVPO77nmRrmDw ti/x5uV9wnIXUIywc/BbxUcrcUbKa+S9MT/dc5vE= Received: from s.wrqvtvvn.outbound-mail.sendgrid.net (s.wrqvtvvn.outbound-mail.sendgrid.net [149.72.120.130]) by nue.mailmanlists.eu (Postfix) with ESMTPS id 4F0B381348 for ; Wed, 17 Apr 2024 00:07:25 +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=aKCY782p; 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=09rAWoIuSN0s29hWMce2IRxB97MWF3w23t1Z04eNi50=; b=aKCY782p4CKPilDZVRi8oFycCEIiFuV+cZtboF5AYyR2oMAWU2+ESbz8b679RuDNlK6G Uhl93MQBvYgZ7RUImjNs3pvn2EZPxqm5IFhVRnJJMXAUidNeAcC70yHvPVee0HabCjos6Y gZr90/yAdgEsCuZFKcgg8uVqg83X7DiIGve9POksPRq2HzN4bxo0Tb7o/dwyibDJoLnN+q tYHryE0XY/I1z9d0tcAPOJSVosXQDpDYDJ3k6atghaEvOgTz5GhssGMtNCGXzWJ/Y/bpp2 x1uow35kJKoCblG1nIRqwNh4LyOzvird7PNPm4CilDslRKjwwB8HujGLfSh0fAsQ== Received: by recvd-6b888cd74b-k8brp with SMTP id recvd-6b888cd74b-k8brp-1-661F12BB-C 2024-04-17 00:07:23.852920018 +0000 UTC m=+353253.002654655 Received: from herokuapp.com (unknown) by geopod-ismtpd-12 (SG) with ESMTP id CnDDJpnhThmxFw8Cpm76ag for ; Wed, 17 Apr 2024 00:07:23.780 +0000 (UTC) Date: Wed, 17 Apr 2024 00:07:22 +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-Issue-Priority: Normal X-Redmine-Sender: ioquatix 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: 94136 X-SG-EID: =?us-ascii?Q?u001=2E3QFJPY5gaRwyNXkncYONHM3OeFnb=2FgeOrLDgg3PYIKrq5rvk81iAipQ1q?= =?us-ascii?Q?cdmuT9o5PIWGjXtTDstodNmslT=2F6xfCuIofWR2K?= =?us-ascii?Q?w8msDgVaVLzvt6Ln7nleeUQ1Vr7b8NoQr9tjuia?= =?us-ascii?Q?uyIym1qTT8slxLWRpZvIkcTe1l=2FVXfg6Pyd3rEp?= =?us-ascii?Q?Yprc+Yv=2FSi+r4zMkyaEkprPkrjY7Q=2FE9oIIVNNI?= =?us-ascii?Q?K5vZ6eI1Tt0aTOGD+9fX3=2FQeb92PW058F0uNgus?= =?us-ascii?Q?2EjnZR=2FFUOPNRZd9dHaQjD02cg=3D=3D?= To: ruby-core@ml.ruby-lang.org X-Entity-ID: u001.I8uzylDtAfgbeCOeLBYDww== Message-ID-Hash: NKLTB2BVBQAL5THXNTHFPGJEGCWR2CBT X-Message-ID-Hash: NKLTB2BVBQAL5THXNTHFPGJEGCWR2CBT 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:117541] [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: "ioquatix (Samuel Williams) via ruby-core" Cc: "ioquatix (Samuel Williams)" Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Issue #20215 has been updated by ioquatix (Samuel Williams). > Even if client.eof? returns false without blocking, it could still result in an EOF with zero read bytes. Therefore, it would be better to do read without unnecessary checks. I understand, thanks for your question. I may not be able to answer this well before the meeting, so I'll try to come up with a clear justification, but if the time frame is too tight, I'll discuss it next time instead. ---------------------------------------- Feature #20215: Introduce `IO#readable?` https://bugs.ruby-lang.org/issues/20215#change-107933 * Author: ioquatix (Samuel Williams) * Status: Open ---------------------------------------- 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/