From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: AS31976 209.132.180.0/23 X-Spam-Status: No, score=-3.4 required=3.0 tests=AWL,BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,RCVD_IN_DNSWL_HI, T_RP_MATCHES_RCVD shortcircuit=no autolearn=ham autolearn_force=no version=3.4.0 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by dcvr.yhbt.net (Postfix) with ESMTP id E1BAF1F404 for ; Wed, 28 Feb 2018 23:23:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964973AbeB1XXZ (ORCPT ); Wed, 28 Feb 2018 18:23:25 -0500 Received: from mail-yb0-f201.google.com ([209.85.213.201]:45502 "EHLO mail-yb0-f201.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S964912AbeB1XXW (ORCPT ); Wed, 28 Feb 2018 18:23:22 -0500 Received: by mail-yb0-f201.google.com with SMTP id w1-v6so2360155ybm.12 for ; Wed, 28 Feb 2018 15:23:21 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:date:in-reply-to:message-id:references:subject:from:to :cc; bh=MIi1D2KxnKV9r62Zkjt8ZnXC7zwWIwQmDbKixAbYflQ=; b=tlnCh14f1JhIWGGIH0MeGmxd7H+h3VSt/IlU9HtsNrSWG+VxziOVVAQ+DMDE1bcboV r6lvM0TmkzR8INoC+gwy0GGRjUGTmb2GYLtmHYpWTUkFZEKGyjT7wvW1RZq2cHpFhQ/d J7Rc3dNSn8UOHRe9UBGVvY4iaQKtMNs9WDcamtBZq1SHA5gtZ9W7adoOlY2zc9Om8Cbh evJ4wQGKXQq6OTYoXLpvJXs+B9Cbohvw7rUWEIY5165UkwjIANFlzuow3eK3++eXajia dS38BilRKQOEBOSzpopfyb0ZYBq45yKYaATQVYNX1CcsvzKeaabofqqvYNcL2w/abh/X hB0A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:date:in-reply-to:message-id :references:subject:from:to:cc; bh=MIi1D2KxnKV9r62Zkjt8ZnXC7zwWIwQmDbKixAbYflQ=; b=MhqswU/TDFqHoZ0Nj/AWshXxZdSWQqgi3qTfRB6eiRnA4IyHdyI3aNrXyqZ5J8wxg6 xQEGGf+x7lw4qiXDkLskbK9G/M57LfOMtIvUn9ZWMmOBepSFd1bYX3l1JLtp5B6CIsnz d3ejLstgQeFkCZYQs2RSawaurAk/jV8xp+r0IrpJGjBfYeoKczQHRnPyc5lPqbjl1TCZ e6roQzJ0F0SAcFFvmfdMM6fp6Xhdm9Dmhad/+9naAPaH8N5IvT8iL6mdKhukBdtOTYYd rrIgSd5ewYtJtN+yONAK96NCu7Ht0Np+xDRS8f3mw+oLJYEZTPj3ESLLiYD/6SMhqLUN s0Kg== X-Gm-Message-State: APf1xPB7gyBxMtSGaQUbQooJTUi9WNGWMizE77REtXjU1sucfpnW4jEp qokdXDX750AeSdlnGwhGbhXMKTCWE37PiUD97G4S5qNcGGapsRooomWO4UERsLLaQ+TX2jowm5Q oI0tzlhkoOFvqB3SlVZkbOiglvvyoGrFZ07s8osMrLwmJb5BsPFRLrDrf/g== X-Google-Smtp-Source: AH8x225nTBnKx9MQ1ZE6p2aEDIVLoMdd3QV9w41weLnZHkzW9bENp8w3QGBl2hcCNIs+kJ6SI3ilGB/meRs= MIME-Version: 1.0 X-Received: by 10.13.247.133 with SMTP id h127mr10060923ywf.113.1519860201014; Wed, 28 Feb 2018 15:23:21 -0800 (PST) Date: Wed, 28 Feb 2018 15:22:19 -0800 In-Reply-To: <20180228232252.102167-1-bmwill@google.com> Message-Id: <20180228232252.102167-3-bmwill@google.com> References: <20180207011312.189834-1-bmwill@google.com> <20180228232252.102167-1-bmwill@google.com> X-Mailer: git-send-email 2.16.1.107.gffe1b9127 Subject: [PATCH v4 02/35] pkt-line: allow peeking a packet line without consuming it From: Brandon Williams To: git@vger.kernel.org Cc: git@jeffhostetler.com, gitster@pobox.com, jrnieder@gmail.com, pclouds@gmail.com, peff@peff.net, sbeller@google.com, stolee@gmail.com, Brandon Williams Content-Type: text/plain; charset="UTF-8" Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Sometimes it is advantageous to be able to peek the next packet line without consuming it (e.g. to be able to determine the protocol version a server is speaking). In order to do that introduce 'struct packet_reader' which is an abstraction around the normal packet reading logic. This enables a caller to be able to peek a single line at a time using 'packet_reader_peek()' and having a caller consume a line by calling 'packet_reader_read()'. Signed-off-by: Brandon Williams --- pkt-line.c | 59 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ pkt-line.h | 58 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 117 insertions(+) diff --git a/pkt-line.c b/pkt-line.c index 08e5ba44c..6307fa4a3 100644 --- a/pkt-line.c +++ b/pkt-line.c @@ -404,3 +404,62 @@ ssize_t read_packetized_to_strbuf(int fd_in, struct strbuf *sb_out) } return sb_out->len - orig_len; } + +/* Packet Reader Functions */ +void packet_reader_init(struct packet_reader *reader, int fd, + char *src_buffer, size_t src_len, + int options) +{ + memset(reader, 0, sizeof(*reader)); + + reader->fd = fd; + reader->src_buffer = src_buffer; + reader->src_len = src_len; + reader->buffer = packet_buffer; + reader->buffer_size = sizeof(packet_buffer); + reader->options = options; +} + +enum packet_read_status packet_reader_read(struct packet_reader *reader) +{ + if (reader->line_peeked) { + reader->line_peeked = 0; + return reader->status; + } + + reader->status = packet_read_with_status(reader->fd, + &reader->src_buffer, + &reader->src_len, + reader->buffer, + reader->buffer_size, + &reader->pktlen, + reader->options); + + switch (reader->status) { + case PACKET_READ_EOF: + reader->pktlen = -1; + reader->line = NULL; + break; + case PACKET_READ_NORMAL: + reader->line = reader->buffer; + break; + case PACKET_READ_FLUSH: + reader->pktlen = 0; + reader->line = NULL; + break; + } + + return reader->status; +} + +enum packet_read_status packet_reader_peek(struct packet_reader *reader) +{ + /* Only allow peeking a single line */ + if (reader->line_peeked) + return reader->status; + + /* Peek a line by reading it and setting peeked flag */ + packet_reader_read(reader); + reader->line_peeked = 1; + return reader->status; +} diff --git a/pkt-line.h b/pkt-line.h index 0be691116..f2edfae9a 100644 --- a/pkt-line.h +++ b/pkt-line.h @@ -112,6 +112,64 @@ char *packet_read_line_buf(char **src_buf, size_t *src_len, int *size); */ ssize_t read_packetized_to_strbuf(int fd_in, struct strbuf *sb_out); +struct packet_reader { + /* source file descriptor */ + int fd; + + /* source buffer and its size */ + char *src_buffer; + size_t src_len; + + /* buffer that pkt-lines are read into and its size */ + char *buffer; + unsigned buffer_size; + + /* options to be used during reads */ + int options; + + /* status of the last read */ + enum packet_read_status status; + + /* length of data read during the last read */ + int pktlen; + + /* the last line read */ + const char *line; + + /* indicates if a line has been peeked */ + int line_peeked; +}; + +/* + * Initialize a 'struct packet_reader' object which is an + * abstraction around the 'packet_read_with_status()' function. + */ +extern void packet_reader_init(struct packet_reader *reader, int fd, + char *src_buffer, size_t src_len, + int options); + +/* + * Perform a packet read and return the status of the read. + * The values of 'pktlen' and 'line' are updated based on the status of the + * read as follows: + * + * PACKET_READ_ERROR: 'pktlen' is set to '-1' and 'line' is set to NULL + * PACKET_READ_NORMAL: 'pktlen' is set to the number of bytes read + * 'line' is set to point at the read line + * PACKET_READ_FLUSH: 'pktlen' is set to '0' and 'line' is set to NULL + */ +extern enum packet_read_status packet_reader_read(struct packet_reader *reader); + +/* + * Peek the next packet line without consuming it and return the status. + * The next call to 'packet_reader_read()' will perform a read of the same line + * that was peeked, consuming the line. + * + * Peeking multiple times without calling 'packet_reader_read()' will return + * the same result. + */ +extern enum packet_read_status packet_reader_peek(struct packet_reader *reader); + #define DEFAULT_PACKET_MAX 1000 #define LARGE_PACKET_MAX 65520 #define LARGE_PACKET_DATA_MAX (LARGE_PACKET_MAX - 4) -- 2.16.2.395.g2e18187dfd-goog