From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 85321C352A5 for ; Mon, 10 Feb 2020 23:44:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 65DE82082F for ; Mon, 10 Feb 2020 23:44:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727561AbgBJXo3 (ORCPT ); Mon, 10 Feb 2020 18:44:29 -0500 Received: from cloud.peff.net ([104.130.231.41]:57000 "HELO cloud.peff.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1727192AbgBJXo2 (ORCPT ); Mon, 10 Feb 2020 18:44:28 -0500 Received: (qmail 3385 invoked by uid 109); 10 Feb 2020 23:44:28 -0000 Received: from Unknown (HELO peff.net) (10.0.1.2) by cloud.peff.net (qpsmtpd/0.94) with SMTP; Mon, 10 Feb 2020 23:44:28 +0000 Authentication-Results: cloud.peff.net; auth=none Received: (qmail 27288 invoked by uid 111); 10 Feb 2020 23:53:15 -0000 Received: from coredump.intra.peff.net (HELO sigill.intra.peff.net) (10.0.0.2) by peff.net (qpsmtpd/0.94) with (TLS_AES_256_GCM_SHA384 encrypted) ESMTPS; Mon, 10 Feb 2020 18:53:15 -0500 Authentication-Results: peff.net; auth=none Date: Mon, 10 Feb 2020 18:44:27 -0500 From: Jeff King To: Eric Sunshine Cc: =?utf-8?B?UmVuw6k=?= Scharfe , Git Mailing List , Junio C Hamano , Taylor Blau Subject: Re: [PATCH v2] strbuf: add and use strbuf_insertstr() Message-ID: <20200210234427.GA632160@coredump.intra.peff.net> References: <019be197-e0aa-1234-e16f-6561d8340023@web.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org On Sun, Feb 09, 2020 at 12:36:22PM -0500, Eric Sunshine wrote: > On Sun, Feb 9, 2020 at 8:45 AM René Scharfe wrote: > > Add a function for inserting a C string into a strbuf. Use it > > throughout the source to get rid of magic string length constants and > > explicit strlen() calls. > > > > Like strbuf_addstr(), implement it as an inline function to avoid the > > implicit strlen() calls to cause runtime overhead. > > > > Signed-off-by: René Scharfe > > --- > > diff --git a/mailinfo.c b/mailinfo.c > > @@ -570,7 +570,7 @@ static int check_header(struct mailinfo *mi, > > len = strlen("Content-Type: "); > > strbuf_add(&sb, line->buf + len, line->len - len); > > decode_header(mi, &sb); > > - strbuf_insert(&sb, 0, "Content-Type: ", len); > > + strbuf_insertstr(&sb, 0, "Content-Type: "); > > handle_content_type(mi, &sb); > > Meh. We've already computed the length of "Content-Type: " a few lines > earlier, so taking advantage of that value when inserting the string > literal is perfectly sensible. Thus, I'm not convinced that this > change is an improvement. I had a similar thought. I kind of wonder if all of these "len" bits (and their repeated strings) could go away if cmp_header() just used skip_iprefix() under the hood and had a pointer out-parameter. Something like the (largely untested) patch below. That would also make it easy to support arbitrary amounts of whitespace after the header, which I think are allowed by the standard (whereas now we'd parse "Content-type: text/plain" as " text/plain", which is silly). Worth doing? --- diff --git a/mailinfo.c b/mailinfo.c index b395adbdf2..bbb5b429f8 100644 --- a/mailinfo.c +++ b/mailinfo.c @@ -346,11 +346,16 @@ static const char *header[MAX_HDR_PARSED] = { "From","Subject","Date", }; -static inline int cmp_header(const struct strbuf *line, const char *hdr) +static inline int cmp_header(const struct strbuf *line, const char *hdr, + const char **outval) { - int len = strlen(hdr); - return !strncasecmp(line->buf, hdr, len) && line->len > len && - line->buf[len] == ':' && isspace(line->buf[len + 1]); + const char *val; + if (!skip_iprefix(line->buf, hdr, &val) || + *val++ != ':' || + !isspace(*val++)) + return 0; + *outval = val; + return 1; } static int is_format_patch_separator(const char *line, int len) @@ -547,17 +552,17 @@ static int check_header(struct mailinfo *mi, const struct strbuf *line, struct strbuf *hdr_data[], int overwrite) { - int i, ret = 0, len; + int i, ret = 0; struct strbuf sb = STRBUF_INIT; + const char *val; /* search for the interesting parts */ for (i = 0; header[i]; i++) { - int len = strlen(header[i]); - if ((!hdr_data[i] || overwrite) && cmp_header(line, header[i])) { + if ((!hdr_data[i] || overwrite) && cmp_header(line, header[i], &val)) { /* Unwrap inline B and Q encoding, and optionally * normalize the meta information to utf8. */ - strbuf_add(&sb, line->buf + len + 2, line->len - len - 2); + strbuf_addstr(&sb, val); decode_header(mi, &sb); handle_header(&hdr_data[i], &sb); ret = 1; @@ -566,26 +571,22 @@ static int check_header(struct mailinfo *mi, } /* Content stuff */ - if (cmp_header(line, "Content-Type")) { - len = strlen("Content-Type: "); - strbuf_add(&sb, line->buf + len, line->len - len); + if (cmp_header(line, "Content-Type", &val)) { + strbuf_addstr(&sb, val); decode_header(mi, &sb); - strbuf_insert(&sb, 0, "Content-Type: ", len); handle_content_type(mi, &sb); ret = 1; goto check_header_out; } - if (cmp_header(line, "Content-Transfer-Encoding")) { - len = strlen("Content-Transfer-Encoding: "); - strbuf_add(&sb, line->buf + len, line->len - len); + if (cmp_header(line, "Content-Transfer-Encoding", &val)) { + strbuf_addstr(&sb, val); decode_header(mi, &sb); handle_content_transfer_encoding(mi, &sb); ret = 1; goto check_header_out; } - if (cmp_header(line, "Message-Id")) { - len = strlen("Message-Id: "); - strbuf_add(&sb, line->buf + len, line->len - len); + if (cmp_header(line, "Message-Id", &val)) { + strbuf_addstr(&sb, val); decode_header(mi, &sb); if (mi->add_message_id) mi->message_id = strbuf_detach(&sb, NULL); @@ -607,8 +608,9 @@ static int is_inbody_header(const struct mailinfo *mi, const struct strbuf *line) { int i; + const char *val; for (i = 0; header[i]; i++) - if (!mi->s_hdr_data[i] && cmp_header(line, header[i])) + if (!mi->s_hdr_data[i] && cmp_header(line, header[i], &val)) return 1; return 0; }