From patchwork Sat Jun 11 02:44:17 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Han Xin X-Patchwork-Id: 12878319 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 926D4C43334 for ; Sat, 11 Jun 2022 02:44:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1349566AbiFKCos (ORCPT ); Fri, 10 Jun 2022 22:44:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48854 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1347920AbiFKCoq (ORCPT ); Fri, 10 Jun 2022 22:44:46 -0400 Received: from mail-pj1-x1033.google.com (mail-pj1-x1033.google.com [IPv6:2607:f8b0:4864:20::1033]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5927A3F4A28 for ; Fri, 10 Jun 2022 19:44:45 -0700 (PDT) Received: by mail-pj1-x1033.google.com with SMTP id gd1so988716pjb.2 for ; Fri, 10 Jun 2022 19:44:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=aAHnND6bDK2oZQJf5VQQH8A7hAEVL5pBw/UAWDyn6/Y=; b=Z8epYP+8N0zhFAUPVFhrCgQndzxbOLHZppfEHwTwTIp16xWALROyctD9JR+qyY14DY /t8gZ3BSgCuCtY0M82DtlT+iFJD2EIelBHe8guyYnuKXRnsBR7QBsmbLwdHZCUdZ/wY4 mYzjBU6giZTta3rv8yA1D/ytP8ro8tMZBJlxqA+PPU+DeOHUwhdoekqkFWIa+9CHr0Hl DOpkyD/snY6zQ5tZa7LoZSev9/h014nAybBLDCdH1Ml18x3FpjpddGInbKFmw17GTYG9 BRYb9NMzUi9nF3bW1Txo3tdwvvplu11V4lm4kPKp4VvO9fZVfOLw7pyG4Gg5h4NOTb3I smpw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=aAHnND6bDK2oZQJf5VQQH8A7hAEVL5pBw/UAWDyn6/Y=; b=G7JljJHdWO1sn+K9IrF6/n9B+Z7u5igeoeaDNOb3s2nY5qUBWggTvLuin1Ge2CtHMt 5hBYVFZ73cYDiOsHiMAICYLoc2gx//qxrkmXLCTlwucID2VGSWJURqqx9chdKdjlKVM+ BfCfavasjnQD+MSTzOFbxjKqEDPbzjX6Tuep/NT+FLvBr6qsS1FBkBf56ZsPtHwBvPaX 5xkieD+Xu7b+HDrbvHLhMIvauAjpWp2F0UWFrVmD+406vm4vOq1VJpWGysMekSWCrCmf UVdrVcJc/Xkb3JKOTqp6eOXLEtDLiS597O/ALJrEbgBfvARbBLznMytiKasdZau9tEqw mqbQ== X-Gm-Message-State: AOAM5330djoHoO2ZKliNeu7VJ69OP/z7By84lp/oZjoQumM0Z4WOFs9n OBjlJe/5TeASTBeCCo62ixs= X-Google-Smtp-Source: ABdhPJybisjALzRIDT4EtJ85S/hVvU03aiH0eqDv2eLtMhCZTDeSIDP7lZV+jaFE27motpLWYL7xbw== X-Received: by 2002:a17:903:181:b0:167:97e3:f67e with SMTP id z1-20020a170903018100b0016797e3f67emr21249272plg.151.1654915484806; Fri, 10 Jun 2022 19:44:44 -0700 (PDT) Received: from localhost.localdomain ([2409:8a28:80c:ca60:6957:cd88:1852:9438]) by smtp.gmail.com with ESMTPSA id l13-20020a62be0d000000b0051ba90d55acsm257077pff.207.2022.06.10.19.44.40 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Fri, 10 Jun 2022 19:44:44 -0700 (PDT) From: Han Xin To: avarab@gmail.com Cc: Han Xin , chiyutianyi@gmail.com, git@vger.kernel.org, gitster@pobox.com, l.s.r@web.de, neerajsi@microsoft.com, newren@gmail.com, philipoakley@iee.email, stolee@gmail.com, worldhello.net@gmail.com, Neeraj Singh , Jiang Xin Subject: [PATCH v15 2/6] object-file.c: refactor write_loose_object() to several steps Date: Sat, 11 Jun 2022 10:44:17 +0800 Message-Id: X-Mailer: git-send-email 2.36.1 In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org From: Han Xin When writing a large blob using "write_loose_object()", we have to pass a buffer with the whole content of the blob, and this behavior will consume lots of memory and may cause OOM. We will introduce a stream version function ("stream_loose_object()") in later commit to resolve this issue. Before introducing that streaming function, do some refactoring on "write_loose_object()" to reuse code for both versions. Rewrite "write_loose_object()" as follows: 1. Figure out a path for the (temp) object file. This step is only used in "write_loose_object()". 2. Move common steps for starting to write loose objects into a new function "start_loose_object_common()". 3. Compress data. 4. Move common steps for ending zlib stream into a new function "end_loose_object_common()". 5. Close fd and finalize the object file. Helped-by: Ævar Arnfjörð Bjarmason Helped-by: Jiang Xin Signed-off-by: Han Xin Signed-off-by: Ævar Arnfjörð Bjarmason --- object-file.c | 98 ++++++++++++++++++++++++++++++++++++++------------- 1 file changed, 74 insertions(+), 24 deletions(-) diff --git a/object-file.c b/object-file.c index 79eb8339b6..b5bce03274 100644 --- a/object-file.c +++ b/object-file.c @@ -1951,6 +1951,74 @@ static int create_tmpfile(struct strbuf *tmp, const char *filename) return fd; } +/** + * Common steps for loose object writers to start writing loose + * objects: + * + * - Create tmpfile for the loose object. + * - Setup zlib stream for compression. + * - Start to feed header to zlib stream. + * + * Returns a "fd", which should later be provided to + * end_loose_object_common(). + */ +static int start_loose_object_common(struct strbuf *tmp_file, + const char *filename, unsigned flags, + git_zstream *stream, + unsigned char *buf, size_t buflen, + git_hash_ctx *c, + char *hdr, int hdrlen) +{ + int fd; + + fd = create_tmpfile(tmp_file, filename); + if (fd < 0) { + if (flags & HASH_SILENT) + return -1; + else if (errno == EACCES) + return error(_("insufficient permission for adding " + "an object to repository database %s"), + get_object_directory()); + else + return error_errno( + _("unable to create temporary file")); + } + + /* Setup zlib stream for compression */ + git_deflate_init(stream, zlib_compression_level); + stream->next_out = buf; + stream->avail_out = buflen; + the_hash_algo->init_fn(c); + + /* Start to feed header to zlib stream */ + stream->next_in = (unsigned char *)hdr; + stream->avail_in = hdrlen; + while (git_deflate(stream, 0) == Z_OK) + ; /* nothing */ + the_hash_algo->update_fn(c, hdr, hdrlen); + + return fd; +} + +/** + * Common steps for loose object writers to end writing loose objects: + * + * - End the compression of zlib stream. + * - Get the calculated oid to "oid". + */ +static int end_loose_object_common(git_hash_ctx *c, git_zstream *stream, + struct object_id *oid) +{ + int ret; + + ret = git_deflate_end_gently(stream); + if (ret != Z_OK) + return ret; + the_hash_algo->final_oid_fn(oid, c); + + return Z_OK; +} + static int write_loose_object(const struct object_id *oid, char *hdr, int hdrlen, const void *buf, unsigned long len, time_t mtime, unsigned flags) @@ -1968,28 +2036,11 @@ static int write_loose_object(const struct object_id *oid, char *hdr, loose_object_path(the_repository, &filename, oid); - fd = create_tmpfile(&tmp_file, filename.buf); - if (fd < 0) { - if (flags & HASH_SILENT) - return -1; - else if (errno == EACCES) - return error(_("insufficient permission for adding an object to repository database %s"), get_object_directory()); - else - return error_errno(_("unable to create temporary file")); - } - - /* Set it up */ - git_deflate_init(&stream, zlib_compression_level); - stream.next_out = compressed; - stream.avail_out = sizeof(compressed); - the_hash_algo->init_fn(&c); - - /* First header.. */ - stream.next_in = (unsigned char *)hdr; - stream.avail_in = hdrlen; - while (git_deflate(&stream, 0) == Z_OK) - ; /* nothing */ - the_hash_algo->update_fn(&c, hdr, hdrlen); + fd = start_loose_object_common(&tmp_file, filename.buf, flags, + &stream, compressed, sizeof(compressed), + &c, hdr, hdrlen); + if (fd < 0) + return -1; /* Then the data itself.. */ stream.next_in = (void *)buf; @@ -2007,11 +2058,10 @@ static int write_loose_object(const struct object_id *oid, char *hdr, if (ret != Z_STREAM_END) die(_("unable to deflate new object %s (%d)"), oid_to_hex(oid), ret); - ret = git_deflate_end_gently(&stream); + ret = end_loose_object_common(&c, &stream, ¶no_oid); if (ret != Z_OK) die(_("deflateEnd on object %s failed (%d)"), oid_to_hex(oid), ret); - the_hash_algo->final_oid_fn(¶no_oid, &c); if (!oideq(oid, ¶no_oid)) die(_("confused by unstable object source data for %s"), oid_to_hex(oid));