From patchwork Tue Jun 13 17:39:55 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jonathan Tan X-Patchwork-Id: 13279109 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 DA54AEB64D8 for ; Tue, 13 Jun 2023 17:40:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234961AbjFMRkY (ORCPT ); Tue, 13 Jun 2023 13:40:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36462 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240069AbjFMRkL (ORCPT ); Tue, 13 Jun 2023 13:40:11 -0400 Received: from mail-yb1-xb49.google.com (mail-yb1-xb49.google.com [IPv6:2607:f8b0:4864:20::b49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D922692 for ; Tue, 13 Jun 2023 10:40:10 -0700 (PDT) Received: by mail-yb1-xb49.google.com with SMTP id 3f1490d57ef6-bd69ee0edacso382167276.3 for ; Tue, 13 Jun 2023 10:40:10 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1686678010; x=1689270010; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=M7KQnfd1RrJljfgV3vlc4SkWbQ9MGK7nBO1blgrMwQU=; b=vtNoLPljHlPLaAGR0omf7PBhig7+ZwiOxgGFRpuQamNqHhyhAGc/cOq24sC71dKBNm arl1E5XbXKAZBSrPE86xn+Rc5dK/f4KrLhSfZ3c20aA5TPzX6uMEb+pn3oC8YtQEXhgs TsTL0bqeIikBT1K9PPEIVX/SkBAbV809kXPTyz1UvoEKR4SS1QdNlFkrRA4/VRmn8nDJ cGY4RzdMgs6QQD+MqIroLktwd8O5UChQp3l/ZdIjK3v0hYAp1pkMLj7NAuerVBdVWwnM Vcf8G7TJ57osavqTqWAg4WQrQSZbPpAwmxksjeAOVBw+a4k7x4pzFotZadJzejV1SroL EURg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1686678010; x=1689270010; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=M7KQnfd1RrJljfgV3vlc4SkWbQ9MGK7nBO1blgrMwQU=; b=DMWIRDDxlIanZ9VTPOTAbbOCUIGJFqqCPc2kkYphXzwqTK0l6pwMjqFSyMUMtnVUwW 8dpMwN8CchLTwPNtMPvtYpUBtEx5a0nY2xb3FpnPKprw6v3+kT3jNEd2dXDSv2rsNFcR fLyblPbNKtYT+Jqb9aZOH2aPG33StTKMU/vScooUdxKBZbz4hFVMpG5tPXno+V+1IsBL K2oAwKPG5WjsBLmmMnOx9YLNx/uXvU9Z8De5JQGb1XQXrXNlsB4JJKJ+yWtWg89BwYm9 Tpx/eYAMPfdiEdtUpv6Esm3VB16JxcBIkZsMVayryjJ/sqU+S15ZdXMc0jcIyGPkX7g9 7nmg== X-Gm-Message-State: AC+VfDwQRE1gwd1+SVzDm1FxyJ1siWJX/w68hiwdDfwtBhyAloksh7Jh 5vCZTTwRXoscXp1+myU0+6YzTmkNkr49yCRqXC57LXFD0NtblAAFSozRjDC5rGQMvoD4UiwPlhv v7rRowcgXejhalq08MRG4wAsBo3jgG3G8BVdkaVU8HZpLtwbnLv34A0vRm9xyMJrPsjPc0GZP26 Au X-Google-Smtp-Source: ACHHUZ6YPN0GSBqL4iX7i2OHdLctm28TVfndK0Vx9+7eFtstlbil2JAGSnwpvZV4juHpipnpbsW3xB0XdqWqWMPxZuq/ X-Received: from jonathantanmy0.svl.corp.google.com ([2620:15c:2d3:202:5e39:4d58:c992:1db0]) (user=jonathantanmy job=sendgmr) by 2002:a25:4487:0:b0:bad:4bb:c440 with SMTP id r129-20020a254487000000b00bad04bbc440mr1051892yba.10.1686678010094; Tue, 13 Jun 2023 10:40:10 -0700 (PDT) Date: Tue, 13 Jun 2023 10:39:55 -0700 In-Reply-To: Mime-Version: 1.0 References: X-Mailer: git-send-email 2.41.0.162.gfafddb0af9-goog Message-ID: Subject: [PATCH v4 1/4] gitformat-commit-graph: describe version 2 of BDAT From: Jonathan Tan To: git@vger.kernel.org Cc: Jonathan Tan , Ramsay Jones , Junio C Hamano Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org The code change to Git to support version 2 will be done in subsequent commits. Signed-off-by: Jonathan Tan --- 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..112e6d36a6 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