From patchwork Tue Mar 30 13:10:54 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Derrick Stolee X-Patchwork-Id: 12172531 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=-12.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,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 8B7A6C433F4 for ; Tue, 30 Mar 2021 13:12:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 68598619D4 for ; Tue, 30 Mar 2021 13:12:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232270AbhC3NLt (ORCPT ); Tue, 30 Mar 2021 09:11:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56698 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232164AbhC3NLR (ORCPT ); Tue, 30 Mar 2021 09:11:17 -0400 Received: from mail-wr1-x432.google.com (mail-wr1-x432.google.com [IPv6:2a00:1450:4864:20::432]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B818EC061574 for ; Tue, 30 Mar 2021 06:11:16 -0700 (PDT) Received: by mail-wr1-x432.google.com with SMTP id c8so16173972wrq.11 for ; Tue, 30 Mar 2021 06:11:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=message-id:in-reply-to:references:from:date:subject:fcc :content-transfer-encoding:mime-version:to:cc; bh=/OlR0ax3xndSWGKKDFthuKiuhYT+sjq9OOppgrZbaSQ=; b=IFsklqqtyKWhVgjvdGbyewfHXtO7SJ0ozoMkFbe2P5t8s7eR3T9rz2y64gE/KeeP8E 4c5MMiudMZWcX2jUFSSyeZT4OttNkklJxrdB6q9BHcM4AA/MrtT/3RVPTnGou+5SAB0S MBRRYheIhDfWDpO9iV+QX6dvtvvNrMGsaiRmrutM3kwhj6bYTXE7oEjwrHZY0d/X3vSK kscIRcS41GBHkyfQ89dQEy/O5pIvkjY8RcsxwUglzoxaV48xs4fIHiLC6I37Av/yX0K1 2g9QROUZ30zgZDL2FihyB3QRtvic83ek3KSOrHW2l35UeJhFx2p5BYWvvFtz5ATmxBVz fl1w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:message-id:in-reply-to:references:from:date :subject:fcc:content-transfer-encoding:mime-version:to:cc; bh=/OlR0ax3xndSWGKKDFthuKiuhYT+sjq9OOppgrZbaSQ=; b=h13zhcZLrH79jrVMrLSPEXQeLcdGTKJiL+CAg61Ge+HBOuB0K1Vf9yXGZmrKmgOIaF jIDkty+MxcypkkjA+N6ILbIz5cRQsPgOG5q2BhspREpizHSMK4WanCU5Tqlsz2U6qziy MtRuA+AczxQNz576U2EYCwT5SOw+CF6TeX7J6w8s0COro3yOgM6Dplm4medeAYlxM3VV DnAxXUTD2EHoVvSEv21G2Cx1ZrpGCsBLpgdhlkIQRG+Ax5+Xi3atBUvgL8m6BIO/aQZj CuccM2WIBrKhhKNWccLmessOTP4co0Wc4i8fVkEBvfiilEFmwsvG4OWqsuOBjsu2nPzG 9fWw== X-Gm-Message-State: AOAM533LSmBnCm6JF/fmKMo+qwwPQx94Z0+33gbqr5sVsjqM4NC2y6Kk SLySzO+ZFTH6nsCVoYw7UBbg3seH4GQ= X-Google-Smtp-Source: ABdhPJxOfY0EsTR8vfowD2HpTmMxqbHX5l/mTI21XhnY87XKwxvs1ZBu63ZdwqIiyVa+85NCt08ZTA== X-Received: by 2002:a5d:63c8:: with SMTP id c8mr33708983wrw.299.1617109875569; Tue, 30 Mar 2021 06:11:15 -0700 (PDT) Received: from [127.0.0.1] ([13.74.141.28]) by smtp.gmail.com with ESMTPSA id 81sm3682171wmc.11.2021.03.30.06.11.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 30 Mar 2021 06:11:15 -0700 (PDT) Message-Id: In-Reply-To: References: Date: Tue, 30 Mar 2021 13:10:54 +0000 Subject: [PATCH v5 11/21] sparse-index: add 'sdir' index extension Fcc: Sent MIME-Version: 1.0 To: git@vger.kernel.org Cc: newren@gmail.com, gitster@pobox.com, pclouds@gmail.com, jrnieder@gmail.com, Martin =?utf-8?b?w4VncmVu?= , Derrick Stolee , SZEDER =?utf-8?b?R8OhYm9y?= , =?utf-8?b?w4Z2YXIgQXJu?= =?utf-8?b?ZmrDtnLDsA==?= Bjarmason , Derrick Stolee , Derrick Stolee Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org From: Derrick Stolee From: Derrick Stolee The index format does not currently allow for sparse directory entries. This violates some expectations that older versions of Git or third-party tools might not understand. We need an indicator inside the index file to warn these tools to not interact with a sparse index unless they are aware of sparse directory entries. Add a new _required_ index extension, 'sdir', that indicates that the index may contain sparse directory entries. This allows us to continue to use the differences in index formats 2, 3, and 4 before we create a new index version 5 in a later change. Signed-off-by: Derrick Stolee --- Documentation/technical/index-format.txt | 12 ++++++++++++ read-cache.c | 9 +++++++++ 2 files changed, 21 insertions(+) diff --git a/Documentation/technical/index-format.txt b/Documentation/technical/index-format.txt index 3b74c05647db..65da0daaa563 100644 --- a/Documentation/technical/index-format.txt +++ b/Documentation/technical/index-format.txt @@ -392,3 +392,15 @@ The remaining data of each directory block is grouped by type: in this block of entries. - 32-bit count of cache entries in this block + +== Sparse Directory Entries + + When using sparse-checkout in cone mode, some entire directories within + the index can be summarized by pointing to a tree object instead of the + entire expanded list of paths within that tree. An index containing such + entries is a "sparse index". Index format versions 4 and less were not + implemented with such entries in mind. Thus, for these versions, an + index containing sparse directory entries will include this extension + with signature { 's', 'd', 'i', 'r' }. Like the split-index extension, + tools should avoid interacting with a sparse index unless they understand + this extension. diff --git a/read-cache.c b/read-cache.c index dd3980c12b53..b8f092d1b7eb 100644 --- a/read-cache.c +++ b/read-cache.c @@ -47,6 +47,7 @@ #define CACHE_EXT_FSMONITOR 0x46534D4E /* "FSMN" */ #define CACHE_EXT_ENDOFINDEXENTRIES 0x454F4945 /* "EOIE" */ #define CACHE_EXT_INDEXENTRYOFFSETTABLE 0x49454F54 /* "IEOT" */ +#define CACHE_EXT_SPARSE_DIRECTORIES 0x73646972 /* "sdir" */ /* changes that can be kept in $GIT_DIR/index (basically all extensions) */ #define EXTMASK (RESOLVE_UNDO_CHANGED | CACHE_TREE_CHANGED | \ @@ -1763,6 +1764,10 @@ static int read_index_extension(struct index_state *istate, case CACHE_EXT_INDEXENTRYOFFSETTABLE: /* already handled in do_read_index() */ break; + case CACHE_EXT_SPARSE_DIRECTORIES: + /* no content, only an indicator */ + istate->sparse_index = 1; + break; default: if (*ext < 'A' || 'Z' < *ext) return error(_("index uses %.4s extension, which we do not understand"), @@ -3020,6 +3025,10 @@ static int do_write_index(struct index_state *istate, struct tempfile *tempfile, if (err) return -1; } + if (istate->sparse_index) { + if (write_index_ext_header(&c, &eoie_c, newfd, CACHE_EXT_SPARSE_DIRECTORIES, 0) < 0) + return -1; + } /* * CACHE_EXT_ENDOFINDEXENTRIES must be written as the last entry before the SHA1