From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: AS31976 209.132.180.0/23 X-Spam-Status: No, score=-2.8 required=3.0 tests=AWL,BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,RCVD_IN_DNSWL_HI,T_RP_MATCHES_RCVD shortcircuit=no autolearn=no autolearn_force=no version=3.4.0 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by dcvr.yhbt.net (Postfix) with ESMTP id E39311F404 for ; Mon, 19 Feb 2018 18:54:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753616AbeBSSyV (ORCPT ); Mon, 19 Feb 2018 13:54:21 -0500 Received: from mail-qk0-f193.google.com ([209.85.220.193]:37095 "EHLO mail-qk0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753494AbeBSSxh (ORCPT ); Mon, 19 Feb 2018 13:53:37 -0500 Received: by mail-qk0-f193.google.com with SMTP id y137so7367671qka.4 for ; Mon, 19 Feb 2018 10:53:37 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=2WXgP2zOSneeCU18TIZZP5jXbeXUCzLm5iuLDEizjf4=; b=hfEIMCBvSyPuMz1S6p4dVN2dmwyGbggdOBaOVn0CmnUsgke6FkuQHIkCd8FPHOC7+d F6VodOjJ/lqnOoGC5EtzcJGjkl43IVr4Rnj+eJlm5as/FR5lFQ/Qmz/Ctjj1pnYwSdkI Rb79B8aMVEo0T1mnb9OKHIvUSccpWcafYqCBPN4227ctpvtVDRYicND1sqTQ+Yf9Q18O YL4C/k9cw9PpZMvxRU/+vTomWCCrCvSeiPcLGrrPPeO9j0pYqvXR6Ihc5eE6cmIMusXc XmWsT9LCqloKpc/oB9H7CWqVWJtfjkEL44+FPNg5T0j6Wbxh4h5PUC3/6xmM+10pDLsc 7YiA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=2WXgP2zOSneeCU18TIZZP5jXbeXUCzLm5iuLDEizjf4=; b=V+cOTGn54TyedRVCQlear+lL/USOjqEg0GE3ECqcxaJBww/ZVt/GxQWjlamBYn0XZE CXWe7Erd8Y7FjyF1KsynnzIKDs+0y5ZVKoibMI0C+cWwbEKwYz4iLmdMD5oDTW0fZhnN pxemL2Top+hLHlgeYNPpG6pdd9af94htT0X56Miw2tP40iueDddAYsGdpqRWiwW8ko8a VWLsCoisIP/yAxLMLhuIYLKhZl6KQbJCUFrSBn+mFk7M2nk4mIJDUlX68daMWfH3sYog hDxdtZ8SkJ87padi3j1APf6fy31kGzJw7BivU6pfuPPwTyqErnZ3IexPerQGt3yr3hZ+ ldhA== X-Gm-Message-State: APf1xPBzKTq62qp9hOTan5pI8YVTHlhO4JKnnbo6eRMLvqbTQVDKnKkJ lk1ezccAYcFdsuBQ46KRXrIj5tbVffc= X-Google-Smtp-Source: AH8x224iUU91jZaC2KgtdCCmAWzWTzgqJtC1JjIkbY7DnWszJSd3GXHKh473UTbeqP/YqQ4msIQCCg== X-Received: by 10.55.87.198 with SMTP id l189mr25300845qkb.325.1519066416341; Mon, 19 Feb 2018 10:53:36 -0800 (PST) Received: from stolee-linux.corp.microsoft.com ([2001:4898:8010:0:eb4a:5dff:fe0f:7308]) by smtp.gmail.com with ESMTPSA id o12sm1672631qke.81.2018.02.19.10.53.35 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Mon, 19 Feb 2018 10:53:35 -0800 (PST) From: Derrick Stolee X-Google-Original-From: Derrick Stolee To: git@vger.kernel.org, git@jeffhostetler.com Cc: peff@peff.net, jonathantanmy@google.com, szeder.dev@gmail.com, sbeller@google.com, gitster@pobox.com, Derrick Stolee Subject: [PATCH v4 04/13] commit-graph: implement write_commit_graph() Date: Mon, 19 Feb 2018 13:53:17 -0500 Message-Id: <1519066406-81663-5-git-send-email-dstolee@microsoft.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1519066406-81663-1-git-send-email-dstolee@microsoft.com> References: <4d1ee202-7d79-d73c-6e05-d0fc85db943c@gmail.com> <1519066406-81663-1-git-send-email-dstolee@microsoft.com> Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Teach Git to write a commit graph file by checking all packed objects to see if they are commits, then store the file in the given object directory. Signed-off-by: Derrick Stolee --- Makefile | 1 + commit-graph.c | 370 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ commit-graph.h | 7 ++ 3 files changed, 378 insertions(+) create mode 100644 commit-graph.c create mode 100644 commit-graph.h diff --git a/Makefile b/Makefile index fc40b81..eeaeb6a 100644 --- a/Makefile +++ b/Makefile @@ -761,6 +761,7 @@ LIB_OBJS += color.o LIB_OBJS += column.o LIB_OBJS += combine-diff.o LIB_OBJS += commit.o +LIB_OBJS += commit-graph.o LIB_OBJS += compat/obstack.o LIB_OBJS += compat/terminal.o LIB_OBJS += config.o diff --git a/commit-graph.c b/commit-graph.c new file mode 100644 index 0000000..f9e39b0 --- /dev/null +++ b/commit-graph.c @@ -0,0 +1,370 @@ +#include "cache.h" +#include "config.h" +#include "git-compat-util.h" +#include "pack.h" +#include "packfile.h" +#include "commit.h" +#include "object.h" +#include "revision.h" +#include "sha1-lookup.h" +#include "commit-graph.h" + +#define GRAPH_SIGNATURE 0x43475048 /* "CGPH" */ +#define GRAPH_CHUNKID_OIDFANOUT 0x4f494446 /* "OIDF" */ +#define GRAPH_CHUNKID_OIDLOOKUP 0x4f49444c /* "OIDL" */ +#define GRAPH_CHUNKID_DATA 0x43444154 /* "CDAT" */ +#define GRAPH_CHUNKID_LARGEEDGES 0x45444745 /* "EDGE" */ + +#define GRAPH_DATA_WIDTH 36 + +#define GRAPH_VERSION_1 0x1 +#define GRAPH_VERSION GRAPH_VERSION_1 + +#define GRAPH_OID_VERSION_SHA1 1 +#define GRAPH_OID_LEN_SHA1 20 +#define GRAPH_OID_VERSION GRAPH_OID_VERSION_SHA1 +#define GRAPH_OID_LEN GRAPH_OID_LEN_SHA1 + +#define GRAPH_LARGE_EDGES_NEEDED 0x80000000 +#define GRAPH_PARENT_MISSING 0x7fffffff +#define GRAPH_EDGE_LAST_MASK 0x7fffffff +#define GRAPH_PARENT_NONE 0x70000000 + +#define GRAPH_LAST_EDGE 0x80000000 + +#define GRAPH_FANOUT_SIZE (4 * 256) +#define GRAPH_CHUNKLOOKUP_WIDTH 12 +#define GRAPH_CHUNKLOOKUP_SIZE (5 * GRAPH_CHUNKLOOKUP_WIDTH) +#define GRAPH_MIN_SIZE (GRAPH_CHUNKLOOKUP_SIZE + GRAPH_FANOUT_SIZE + \ + GRAPH_OID_LEN + 8) + +static void write_graph_chunk_fanout(struct sha1file *f, + struct commit **commits, + int nr_commits) +{ + uint32_t i, count = 0; + struct commit **list = commits; + struct commit **last = commits + nr_commits; + + /* + * Write the first-level table (the list is sorted, + * but we use a 256-entry lookup to be able to avoid + * having to do eight extra binary search iterations). + */ + for (i = 0; i < 256; i++) { + while (list < last) { + if ((*list)->object.oid.hash[0] != i) + break; + count++; + list++; + } + + sha1write_be32(f, count); + } +} + +static void write_graph_chunk_oids(struct sha1file *f, int hash_len, + struct commit **commits, int nr_commits) +{ + struct commit **list, **last = commits + nr_commits; + for (list = commits; list < last; list++) + sha1write(f, (*list)->object.oid.hash, (int)hash_len); +} + +static int commit_pos(struct commit **commits, int nr_commits, + const struct object_id *oid, uint32_t *pos) +{ + uint32_t first = 0, last = nr_commits; + + while (first < last) { + uint32_t mid = first + (last - first) / 2; + struct object_id *current; + int cmp; + + current = &(commits[mid]->object.oid); + cmp = oidcmp(oid, current); + if (!cmp) { + *pos = mid; + return 1; + } + if (cmp > 0) { + first = mid + 1; + continue; + } + last = mid; + } + + *pos = first; + return 0; +} + +static void write_graph_chunk_data(struct sha1file *f, int hash_len, + struct commit **commits, int nr_commits) +{ + struct commit **list = commits; + struct commit **last = commits + nr_commits; + uint32_t num_large_edges = 0; + + while (list < last) { + struct commit_list *parent; + uint32_t int_id; + uint32_t packedDate[2]; + + parse_commit(*list); + sha1write(f, (*list)->tree->object.oid.hash, hash_len); + + parent = (*list)->parents; + + if (!parent) + int_id = GRAPH_PARENT_NONE; + else if (!commit_pos(commits, nr_commits, + &(parent->item->object.oid), &int_id)) + int_id = GRAPH_PARENT_MISSING; + + sha1write_be32(f, int_id); + + if (parent) + parent = parent->next; + + if (!parent) + int_id = GRAPH_PARENT_NONE; + else if (parent->next) + int_id = GRAPH_LARGE_EDGES_NEEDED | num_large_edges; + else if (!commit_pos(commits, nr_commits, + &(parent->item->object.oid), &int_id)) + int_id = GRAPH_PARENT_MISSING; + + sha1write_be32(f, int_id); + + if (parent && parent->next) { + do { + num_large_edges++; + parent = parent->next; + } while (parent); + } + + if (sizeof((*list)->date) > 4) + packedDate[0] = htonl(((*list)->date >> 32) & 0x3); + else + packedDate[0] = 0; + + packedDate[1] = htonl((*list)->date); + sha1write(f, packedDate, 8); + + list++; + } +} + +static void write_graph_chunk_large_edges(struct sha1file *f, + struct commit **commits, + int nr_commits) +{ + struct commit **list = commits; + struct commit **last = commits + nr_commits; + struct commit_list *parent; + + while (list < last) { + int num_parents = 0; + for (parent = (*list)->parents; num_parents < 3 && parent; + parent = parent->next) + num_parents++; + + if (num_parents <= 2) { + list++; + continue; + } + + /* Since num_parents > 2, this initializer is safe. */ + for (parent = (*list)->parents->next; parent; parent = parent->next) { + uint32_t int_id, swap_int_id; + uint32_t last_edge = 0; + if (!parent->next) + last_edge |= GRAPH_LAST_EDGE; + + if (commit_pos(commits, nr_commits, + &(parent->item->object.oid), + &int_id)) + swap_int_id = htonl(int_id | last_edge); + else + swap_int_id = htonl(GRAPH_PARENT_MISSING | last_edge); + + sha1write(f, &swap_int_id, 4); + } + + list++; + } +} + +static int commit_compare(const void *_a, const void *_b) +{ + struct object_id *a = (struct object_id *)_a; + struct object_id *b = (struct object_id *)_b; + return oidcmp(a, b); +} + +struct packed_commit_list { + struct commit **list; + int nr; + int alloc; +}; + +struct packed_oid_list { + struct object_id *list; + int nr; + int alloc; +}; + +static int if_packed_commit_add_to_list(const struct object_id *oid, + struct packed_git *pack, + uint32_t pos, + void *data) +{ + struct packed_oid_list *list = (struct packed_oid_list*)data; + enum object_type type; + unsigned long size; + void *inner_data; + off_t offset = nth_packed_object_offset(pack, pos); + inner_data = unpack_entry(pack, offset, &type, &size); + + if (inner_data) + free(inner_data); + + if (type != OBJ_COMMIT) + return 0; + + ALLOC_GROW(list->list, list->nr + 1, list->alloc); + oidcpy(&(list->list[list->nr]), oid); + (list->nr)++; + + return 0; +} + +char *write_commit_graph(const char *obj_dir) +{ + struct packed_oid_list oids; + struct packed_commit_list commits; + struct sha1file *f; + int i, count_distinct = 0; + DIR *info_dir; + struct strbuf tmp_file = STRBUF_INIT; + struct strbuf graph_file = STRBUF_INIT; + unsigned char final_hash[GIT_MAX_RAWSZ]; + char *graph_name; + int fd; + uint32_t chunk_ids[5]; + uint64_t chunk_offsets[5]; + int num_chunks; + int num_long_edges; + struct commit_list *parent; + + oids.nr = 0; + oids.alloc = (int)(0.15 * approximate_object_count()); + + if (oids.alloc < 1024) + oids.alloc = 1024; + ALLOC_ARRAY(oids.list, oids.alloc); + + for_each_packed_object(if_packed_commit_add_to_list, &oids, 0); + + QSORT(oids.list, oids.nr, commit_compare); + + count_distinct = 1; + for (i = 1; i < oids.nr; i++) { + if (oidcmp(&oids.list[i-1], &oids.list[i])) + count_distinct++; + } + + commits.nr = 0; + commits.alloc = count_distinct; + ALLOC_ARRAY(commits.list, commits.alloc); + + num_long_edges = 0; + for (i = 0; i < oids.nr; i++) { + int num_parents = 0; + if (i > 0 && !oidcmp(&oids.list[i-1], &oids.list[i])) + continue; + + commits.list[commits.nr] = lookup_commit(&oids.list[i]); + parse_commit(commits.list[commits.nr]); + + for (parent = commits.list[commits.nr]->parents; + parent; parent = parent->next) + num_parents++; + + if (num_parents > 2) + num_long_edges += num_parents - 1; + + commits.nr++; + } + num_chunks = num_long_edges ? 4 : 3; + + strbuf_addf(&tmp_file, "%s/info", obj_dir); + info_dir = opendir(tmp_file.buf); + + if (!info_dir && mkdir(tmp_file.buf, 0777) < 0) + die_errno(_("cannot mkdir %s"), tmp_file.buf); + if (info_dir) + closedir(info_dir); + + strbuf_addstr(&tmp_file, "/tmp_graph_XXXXXX"); + + fd = git_mkstemp_mode(tmp_file.buf, 0444); + if (fd < 0) + die_errno("unable to create '%s'", tmp_file.buf); + + f = sha1fd(fd, tmp_file.buf); + + sha1write_be32(f, GRAPH_SIGNATURE); + + sha1write_u8(f, GRAPH_VERSION); + sha1write_u8(f, GRAPH_OID_VERSION); + sha1write_u8(f, num_chunks); + sha1write_u8(f, 0); /* unused padding byte */ + + chunk_ids[0] = GRAPH_CHUNKID_OIDFANOUT; + chunk_ids[1] = GRAPH_CHUNKID_OIDLOOKUP; + chunk_ids[2] = GRAPH_CHUNKID_DATA; + if (num_long_edges) + chunk_ids[3] = GRAPH_CHUNKID_LARGEEDGES; + else + chunk_ids[3] = 0; + chunk_ids[4] = 0; + + chunk_offsets[0] = 8 + GRAPH_CHUNKLOOKUP_SIZE; + chunk_offsets[1] = chunk_offsets[0] + GRAPH_FANOUT_SIZE; + chunk_offsets[2] = chunk_offsets[1] + GRAPH_OID_LEN * commits.nr; + chunk_offsets[3] = chunk_offsets[2] + (GRAPH_OID_LEN + 16) * commits.nr; + chunk_offsets[4] = chunk_offsets[3] + 4 * num_long_edges; + + for (i = 0; i <= num_chunks; i++) { + uint32_t chunk_write[3]; + + chunk_write[0] = htonl(chunk_ids[i]); + chunk_write[1] = htonl(chunk_offsets[i] >> 32); + chunk_write[2] = htonl(chunk_offsets[i] & 0xffffffff); + sha1write(f, chunk_write, 12); + } + + write_graph_chunk_fanout(f, commits.list, commits.nr); + write_graph_chunk_oids(f, GRAPH_OID_LEN, commits.list, commits.nr); + write_graph_chunk_data(f, GRAPH_OID_LEN, commits.list, commits.nr); + write_graph_chunk_large_edges(f, commits.list, commits.nr); + + sha1close(f, final_hash, CSUM_CLOSE | CSUM_FSYNC); + + strbuf_addf(&graph_file, "graph-%s.graph", sha1_to_hex(final_hash)); + graph_name = strbuf_detach(&graph_file, NULL); + strbuf_addf(&graph_file, "%s/info/%s", obj_dir, graph_name); + + if (rename(tmp_file.buf, graph_file.buf)) + die("failed to rename %s to %s", tmp_file.buf, graph_file.buf); + + strbuf_release(&tmp_file); + strbuf_release(&graph_file); + free(oids.list); + oids.alloc = 0; + oids.nr = 0; + + return graph_name; +} + diff --git a/commit-graph.h b/commit-graph.h new file mode 100644 index 0000000..dc8c73a --- /dev/null +++ b/commit-graph.h @@ -0,0 +1,7 @@ +#ifndef COMMIT_GRAPH_H +#define COMMIT_GRAPH_H + +extern char *write_commit_graph(const char *obj_dir); + +#endif + -- 2.7.4