From patchwork Wed Oct 18 18:32:40 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Taylor Blau X-Patchwork-Id: 13427731 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 83DB747366 for ; Wed, 18 Oct 2023 18:32:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=ttaylorr-com.20230601.gappssmtp.com header.i=@ttaylorr-com.20230601.gappssmtp.com header.b="PbMZSGTq" Received: from mail-qk1-x72e.google.com (mail-qk1-x72e.google.com [IPv6:2607:f8b0:4864:20::72e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6A89E118 for ; Wed, 18 Oct 2023 11:32:42 -0700 (PDT) Received: by mail-qk1-x72e.google.com with SMTP id af79cd13be357-77897c4ac1fso45574685a.3 for ; Wed, 18 Oct 2023 11:32:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ttaylorr-com.20230601.gappssmtp.com; s=20230601; t=1697653961; x=1698258761; darn=vger.kernel.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=vZMUe/8alzUbB7b+lpZKgiTlzrBoUML86Vq+SVEl2Wg=; b=PbMZSGTqZLxGkhIJnJeDUojespU242p4PuaTWpMUJshgWHBJXGno3ZbW7CqqZhT5FC jYuTWsjaWUxsFH9y1nMoks32o4k/v3KMLMHPXzwxmzR3ka7WnMtvTqNSbhVlPe/BU3NU cP+QA5U/och5CNiTixM0vvy7zBLjmWPXcTozwa17WJSrx5E+uP3cnvrSBGSuZLNmQp3n zJZsdlKcxsG6qJwBz4EFtC0tJtZgKqabToJ/jj2QnxJWY5NqFvOoPGx6Q4u15TGw7Ey2 D48hw+GouM6SzhDyzK35vx9VYp7yZEULpSnMDMcSeCkToaooCBQT860hi4FhXb11OFxP LUeg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1697653961; x=1698258761; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=vZMUe/8alzUbB7b+lpZKgiTlzrBoUML86Vq+SVEl2Wg=; b=fOrqbFDMAXvvA/MkTEoCyYDzjFtuUXhv6FwcGUpJZODReR5zhyZyxef208w5UGfi+L OP7QEGtgaxvZjRutV+pmJf8xZNgOJA8zJjVSDUINRzhC9Euoe6hNkQ6xK5PHTrxqj8uy DjYflqO229WbAI2tjoOvO6U375kudKZa12o0jB19phARwfmwEY1h5sxlm5OipK40UO0a OYjR4QUddzVNTKaBQbNeo2//p+hpx7y5IBjMlzG7tkzh3yfVCbb6prRQcHMrwDzm7YV3 e033QO1IgZ2MONLGWXsP9aKIIvEYiULAwVg5YUB4xWNQxPzFYTdrVOu4S6rhT5wxP2ty QvJQ== X-Gm-Message-State: AOJu0YwDsjZac4Gx9P5ZLFNFhwwhCE42totpD4H3TSyR8H2DGF9Hx0G0 YdK4Ll6cnnq43+Cm7FqcWGgl7V7qbEV1yNyt5Hx8QQ== X-Google-Smtp-Source: AGHT+IE7tzosb/m9rNoMkUF/k67+f0UGvg8yW1nG9J2RvSF8jqzijpKXGpYEIFl4/HePEOaaq1MQ+w== X-Received: by 2002:a05:620a:44d0:b0:777:784:3458 with SMTP id y16-20020a05620a44d000b0077707843458mr7821937qkp.64.1697653961338; Wed, 18 Oct 2023 11:32:41 -0700 (PDT) Received: from localhost (104-178-186-189.lightspeed.milwwi.sbcglobal.net. [104.178.186.189]) by smtp.gmail.com with ESMTPSA id o14-20020ae9f50e000000b0076d6a08ac98sm149832qkg.76.2023.10.18.11.32.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 18 Oct 2023 11:32:41 -0700 (PDT) Date: Wed, 18 Oct 2023 14:32:40 -0400 From: Taylor Blau To: git@vger.kernel.org Cc: Elijah Newren , "Eric W. Biederman" , Jeff King , Junio C Hamano , Patrick Steinhardt Subject: [PATCH v4 04/17] gitformat-commit-graph: describe version 2 of BDAT Message-ID: <4d0190a9926bddc691cfa5b856d02b7bcc3a1d81.1697653929.git.me@ttaylorr.com> References: Precedence: bulk X-Mailing-List: git@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,RCVD_IN_DNSWL_BLOCKED,SPF_HELO_NONE,SPF_NONE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net From: Jonathan Tan The code change to Git to support version 2 will be done in subsequent commits. Signed-off-by: Jonathan Tan Signed-off-by: Junio C Hamano Signed-off-by: Taylor Blau --- Documentation/gitformat-commit-graph.txt | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/Documentation/gitformat-commit-graph.txt b/Documentation/gitformat-commit-graph.txt index 31cad585e2..3e906e8030 100644 --- a/Documentation/gitformat-commit-graph.txt +++ b/Documentation/gitformat-commit-graph.txt @@ -142,13 +142,16 @@ All multi-byte numbers are in network byte order. ==== Bloom Filter Data (ID: {'B', 'D', 'A', 'T'}) [Optional] * It starts with header consisting of three unsigned 32-bit integers: - - Version of the hash algorithm being used. We currently only support - value 1 which corresponds to the 32-bit version of the murmur3 hash + - Version of the hash algorithm being used. We currently support + value 2 which corresponds to the 32-bit version of the murmur3 hash implemented exactly as described in https://en.wikipedia.org/wiki/MurmurHash#Algorithm and the double hashing technique using seed values 0x293ae76f and 0x7e646e2 as described in https://doi.org/10.1007/978-3-540-30494-4_26 "Bloom Filters - in Probabilistic Verification" + in Probabilistic Verification". Version 1 Bloom filters have a bug that appears + when char is signed and the repository has path names that have characters >= + 0x80; Git supports reading and writing them, but this ability will be removed + in a future version of Git. - The number of times a path is hashed and hence the number of bit positions that cumulatively determine whether a file is present in the commit. - The minimum number of bits 'b' per entry in the Bloom filter. If the filter