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From: "Derrick Stolee via GitGitGadget" <gitgitgadget@gmail.com>
To: git@vger.kernel.org
Cc: peff@peff.net, avarab@gmail.com, git@jeffhostetler.com,
	jrnieder@google.com, steadmon@google.com,
	johannes.schindelin@gmx.de, philipoakley@iee.org,
	Junio C Hamano <gitster@pobox.com>,
	Derrick Stolee <dstolee@microsoft.com>
Subject: [PATCH v6 02/18] commit-graph: prepare for commit-graph chains
Date: Tue, 18 Jun 2019 11:14:24 -0700 (PDT)	[thread overview]
Message-ID: <a06428d749198c180fe0cade50251e0c6b048658.1560881661.git.gitgitgadget@gmail.com> (raw)
In-Reply-To: <pull.184.v6.git.gitgitgadget@gmail.com>

From: Derrick Stolee <dstolee@microsoft.com>

To prepare for a chain of commit-graph files, augment the
commit_graph struct to point to a base commit_graph. As we load
commits from the graph, we may actually want to read from a base
file according to the graph position.

The "graph position" of a commit is given by concatenating the
lexicographic commit orders from each of the commit-graph files in
the chain. This means that we must distinguish two values:

 * lexicographic index : the position within the lexicographic
   order in a single commit-graph file.

 * graph position: the position within the concatenated order
   of multiple commit-graph files

Given the lexicographic index of a commit in a graph, we can
compute the graph position by adding the number of commits in
the lower-level graphs. To find the lexicographic index of
a commit, we subtract the number of commits in lower-level graphs.

While here, change insert_parent_or_die() to take a uint32_t
position, as that is the type used by its only caller and that
makes more sense with the limits in the commit-graph format.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
---
 commit-graph.c | 89 +++++++++++++++++++++++++++++++++++++++++++-------
 commit-graph.h |  3 ++
 2 files changed, 81 insertions(+), 11 deletions(-)

diff --git a/commit-graph.c b/commit-graph.c
index 76d189de45..8f5c09363c 100644
--- a/commit-graph.c
+++ b/commit-graph.c
@@ -359,9 +359,18 @@ int generation_numbers_enabled(struct repository *r)
 	return !!first_generation;
 }
 
+static void close_commit_graph_one(struct commit_graph *g)
+{
+	if (!g)
+		return;
+
+	close_commit_graph_one(g->base_graph);
+	free_commit_graph(g);
+}
+
 void close_commit_graph(struct raw_object_store *o)
 {
-	free_commit_graph(o->commit_graph);
+	close_commit_graph_one(o->commit_graph);
 	o->commit_graph = NULL;
 }
 
@@ -371,18 +380,38 @@ static int bsearch_graph(struct commit_graph *g, struct object_id *oid, uint32_t
 			    g->chunk_oid_lookup, g->hash_len, pos);
 }
 
+static void load_oid_from_graph(struct commit_graph *g,
+				uint32_t pos,
+				struct object_id *oid)
+{
+	uint32_t lex_index;
+
+	while (g && pos < g->num_commits_in_base)
+		g = g->base_graph;
+
+	if (!g)
+		BUG("NULL commit-graph");
+
+	if (pos >= g->num_commits + g->num_commits_in_base)
+		die(_("invalid commit position. commit-graph is likely corrupt"));
+
+	lex_index = pos - g->num_commits_in_base;
+
+	hashcpy(oid->hash, g->chunk_oid_lookup + g->hash_len * lex_index);
+}
+
 static struct commit_list **insert_parent_or_die(struct repository *r,
 						 struct commit_graph *g,
-						 uint64_t pos,
+						 uint32_t pos,
 						 struct commit_list **pptr)
 {
 	struct commit *c;
 	struct object_id oid;
 
-	if (pos >= g->num_commits)
-		die("invalid parent position %"PRIu64, pos);
+	if (pos >= g->num_commits + g->num_commits_in_base)
+		die("invalid parent position %"PRIu32, pos);
 
-	hashcpy(oid.hash, g->chunk_oid_lookup + g->hash_len * pos);
+	load_oid_from_graph(g, pos, &oid);
 	c = lookup_commit(r, &oid);
 	if (!c)
 		die(_("could not find commit %s"), oid_to_hex(&oid));
@@ -392,7 +421,14 @@ static struct commit_list **insert_parent_or_die(struct repository *r,
 
 static void fill_commit_graph_info(struct commit *item, struct commit_graph *g, uint32_t pos)
 {
-	const unsigned char *commit_data = g->chunk_commit_data + GRAPH_DATA_WIDTH * pos;
+	const unsigned char *commit_data;
+	uint32_t lex_index;
+
+	while (pos < g->num_commits_in_base)
+		g = g->base_graph;
+
+	lex_index = pos - g->num_commits_in_base;
+	commit_data = g->chunk_commit_data + GRAPH_DATA_WIDTH * lex_index;
 	item->graph_pos = pos;
 	item->generation = get_be32(commit_data + g->hash_len + 8) >> 2;
 }
@@ -405,10 +441,25 @@ static int fill_commit_in_graph(struct repository *r,
 	uint32_t *parent_data_ptr;
 	uint64_t date_low, date_high;
 	struct commit_list **pptr;
-	const unsigned char *commit_data = g->chunk_commit_data + (g->hash_len + 16) * pos;
+	const unsigned char *commit_data;
+	uint32_t lex_index;
 
-	item->object.parsed = 1;
+	while (pos < g->num_commits_in_base)
+		g = g->base_graph;
+
+	if (pos >= g->num_commits + g->num_commits_in_base)
+		die(_("invalid commit position. commit-graph is likely corrupt"));
+
+	/*
+	 * Store the "full" position, but then use the
+	 * "local" position for the rest of the calculation.
+	 */
 	item->graph_pos = pos;
+	lex_index = pos - g->num_commits_in_base;
+
+	commit_data = g->chunk_commit_data + (g->hash_len + 16) * lex_index;
+
+	item->object.parsed = 1;
 
 	item->maybe_tree = NULL;
 
@@ -452,7 +503,18 @@ static int find_commit_in_graph(struct commit *item, struct commit_graph *g, uin
 		*pos = item->graph_pos;
 		return 1;
 	} else {
-		return bsearch_graph(g, &(item->object.oid), pos);
+		struct commit_graph *cur_g = g;
+		uint32_t lex_index;
+
+		while (cur_g && !bsearch_graph(cur_g, &(item->object.oid), &lex_index))
+			cur_g = cur_g->base_graph;
+
+		if (cur_g) {
+			*pos = lex_index + cur_g->num_commits_in_base;
+			return 1;
+		}
+
+		return 0;
 	}
 }
 
@@ -492,8 +554,13 @@ static struct tree *load_tree_for_commit(struct repository *r,
 					 struct commit *c)
 {
 	struct object_id oid;
-	const unsigned char *commit_data = g->chunk_commit_data +
-					   GRAPH_DATA_WIDTH * (c->graph_pos);
+	const unsigned char *commit_data;
+
+	while (c->graph_pos < g->num_commits_in_base)
+		g = g->base_graph;
+
+	commit_data = g->chunk_commit_data +
+			GRAPH_DATA_WIDTH * (c->graph_pos - g->num_commits_in_base);
 
 	hashcpy(oid.hash, commit_data);
 	c->maybe_tree = lookup_tree(r, &oid);
diff --git a/commit-graph.h b/commit-graph.h
index 390c7f6961..5819910a5b 100644
--- a/commit-graph.h
+++ b/commit-graph.h
@@ -48,6 +48,9 @@ struct commit_graph {
 	uint32_t num_commits;
 	struct object_id oid;
 
+	uint32_t num_commits_in_base;
+	struct commit_graph *base_graph;
+
 	const uint32_t *chunk_oid_fanout;
 	const unsigned char *chunk_oid_lookup;
 	const unsigned char *chunk_commit_data;
-- 
gitgitgadget


  parent reply	other threads:[~2019-06-18 18:14 UTC|newest]

Thread overview: 136+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-08 15:53 [PATCH 00/17] [RFC] Commit-graph: Write incremental files Derrick Stolee via GitGitGadget
2019-05-08 15:53 ` [PATCH 01/17] commit-graph: fix the_repository reference Derrick Stolee via GitGitGadget
2019-05-08 15:53 ` [PATCH 02/17] commit-graph: return with errors during write Derrick Stolee via GitGitGadget
2019-05-08 15:53 ` [PATCH 03/17] commit-graph: collapse parameters into flags Derrick Stolee via GitGitGadget
2019-05-08 15:53 ` [PATCH 04/17] commit-graph: remove Future Work section Derrick Stolee via GitGitGadget
2019-05-08 15:53 ` [PATCH 05/17] commit-graph: create write_commit_graph_context Derrick Stolee via GitGitGadget
2019-05-08 15:53 ` [PATCH 06/17] commit-graph: extract fill_oids_from_packs() Derrick Stolee via GitGitGadget
2019-05-08 15:53 ` [PATCH 07/17] commit-graph: extract fill_oids_from_commit_hex() Derrick Stolee via GitGitGadget
2019-05-08 15:53 ` [PATCH 08/17] commit-graph: extract fill_oids_from_all_packs() Derrick Stolee via GitGitGadget
2019-05-08 15:53 ` [PATCH 09/17] commit-graph: extract count_distinct_commits() Derrick Stolee via GitGitGadget
2019-05-08 15:53 ` [PATCH 10/17] commit-graph: extract copy_oids_to_commits() Derrick Stolee via GitGitGadget
2019-05-08 15:53 ` [PATCH 11/17] commit-graph: extract write_commit_graph_file() Derrick Stolee via GitGitGadget
2019-05-08 15:53 ` [PATCH 12/17] Documentation: describe split commit-graphs Derrick Stolee via GitGitGadget
2019-05-08 17:20   ` SZEDER Gábor
2019-05-08 19:00     ` Derrick Stolee
2019-05-08 20:11       ` Ævar Arnfjörð Bjarmason
2019-05-09  4:49         ` Junio C Hamano
2019-05-09 12:25           ` Derrick Stolee
2019-05-09 13:45         ` Derrick Stolee
2019-05-09 15:48           ` Ævar Arnfjörð Bjarmason
2019-05-09 17:08             ` Derrick Stolee
2019-05-09 21:45               ` Ævar Arnfjörð Bjarmason
2019-05-10 12:44                 ` Derrick Stolee
2019-05-08 15:53 ` [PATCH 13/17] commit-graph: lay groundwork for incremental files Derrick Stolee via GitGitGadget
2019-05-08 15:53 ` [PATCH 14/17] commit-graph: load split commit-graph files Derrick Stolee via GitGitGadget
2019-05-08 15:54 ` [PATCH 15/17] commit-graph: write " Derrick Stolee via GitGitGadget
2019-05-08 15:54 ` [PATCH 16/17] commit-graph: add --split option Derrick Stolee via GitGitGadget
2019-05-08 15:54 ` [PATCH 17/17] fetch: add fetch.writeCommitGraph config setting Derrick Stolee via GitGitGadget
2019-05-09  8:07   ` Ævar Arnfjörð Bjarmason
2019-05-09 14:21     ` Derrick Stolee
2019-05-08 19:27 ` [PATCH 00/17] [RFC] Commit-graph: Write incremental files Ævar Arnfjörð Bjarmason
2019-05-22 19:53 ` [PATCH v2 00/11] " Derrick Stolee via GitGitGadget
2019-05-22 19:53   ` [PATCH v2 01/11] commit-graph: document commit-graph chains Derrick Stolee via GitGitGadget
2019-05-22 19:53   ` [PATCH v2 02/11] commit-graph: prepare for " Derrick Stolee via GitGitGadget
2019-05-22 19:53   ` [PATCH v2 03/11] commit-graph: rename commit_compare to oid_compare Derrick Stolee via GitGitGadget
2019-05-22 19:53   ` [PATCH v2 05/11] commit-graph: add base graphs chunk Derrick Stolee via GitGitGadget
2019-05-22 19:53   ` [PATCH v2 04/11] commit-graph: load commit-graph chains Derrick Stolee via GitGitGadget
2019-05-22 19:53   ` [PATCH v2 06/11] commit-graph: rearrange chunk count logic Derrick Stolee via GitGitGadget
2019-05-22 19:53   ` [PATCH v2 08/11] commit-graph: add --split option to builtin Derrick Stolee via GitGitGadget
2019-05-27 11:28     ` SZEDER Gábor
2019-05-22 19:53   ` [PATCH v2 07/11] commit-graph: write commit-graph chains Derrick Stolee via GitGitGadget
2019-05-22 19:53   ` [PATCH v2 09/11] commit-graph: merge " Derrick Stolee via GitGitGadget
2019-05-23  0:43     ` Ævar Arnfjörð Bjarmason
2019-05-23 13:00       ` Derrick Stolee
2019-05-22 19:53   ` [PATCH v2 10/11] commit-graph: allow cross-alternate chains Derrick Stolee via GitGitGadget
2019-05-22 19:53   ` [PATCH v2 11/11] commit-graph: expire commit-graph files Derrick Stolee via GitGitGadget
2019-06-03 16:03   ` [PATCH v3 00/14] Commit-graph: Write incremental files Derrick Stolee via GitGitGadget
2019-06-03 16:03     ` [PATCH v3 01/14] commit-graph: document commit-graph chains Derrick Stolee via GitGitGadget
2019-06-05 17:22       ` Junio C Hamano
2019-06-05 18:09         ` Derrick Stolee
2019-06-06 12:10       ` Philip Oakley
2019-06-06 17:09         ` Derrick Stolee
2019-06-06 21:59           ` Philip Oakley
2019-06-03 16:03     ` [PATCH v3 02/14] commit-graph: prepare for " Derrick Stolee via GitGitGadget
2019-06-03 16:03     ` [PATCH v3 03/14] commit-graph: rename commit_compare to oid_compare Derrick Stolee via GitGitGadget
2019-06-03 16:03     ` [PATCH v3 04/14] commit-graph: load commit-graph chains Derrick Stolee via GitGitGadget
2019-06-03 16:03     ` [PATCH v3 05/14] commit-graph: add base graphs chunk Derrick Stolee via GitGitGadget
2019-06-03 16:03     ` [PATCH v3 06/14] commit-graph: rearrange chunk count logic Derrick Stolee via GitGitGadget
2019-06-03 16:03     ` [PATCH v3 07/14] commit-graph: write commit-graph chains Derrick Stolee via GitGitGadget
2019-06-03 16:03     ` [PATCH v3 08/14] commit-graph: add --split option to builtin Derrick Stolee via GitGitGadget
2019-06-03 16:03     ` [PATCH v3 09/14] commit-graph: merge commit-graph chains Derrick Stolee via GitGitGadget
2019-06-03 16:03     ` [PATCH v3 10/14] commit-graph: allow cross-alternate chains Derrick Stolee via GitGitGadget
2019-06-03 16:03     ` [PATCH v3 11/14] commit-graph: expire commit-graph files Derrick Stolee via GitGitGadget
2019-06-03 16:04     ` [PATCH v3 12/14] commit-graph: create options for split files Derrick Stolee via GitGitGadget
2019-06-03 16:04     ` [PATCH v3 13/14] commit-graph: verify chains with --shallow mode Derrick Stolee via GitGitGadget
2019-06-03 16:04     ` [PATCH v3 14/14] commit-graph: clean up chains after flattened write Derrick Stolee via GitGitGadget
2019-06-06 14:15     ` [PATCH v4 00/14] Commit-graph: Write incremental files Derrick Stolee via GitGitGadget
2019-06-06 14:15       ` [PATCH v4 01/14] commit-graph: document commit-graph chains Derrick Stolee via GitGitGadget
2019-06-06 14:15       ` [PATCH v4 02/14] commit-graph: prepare for " Derrick Stolee via GitGitGadget
2019-06-06 15:19         ` Philip Oakley
2019-06-06 21:28         ` Junio C Hamano
2019-06-07 12:44           ` Derrick Stolee
2019-06-06 14:15       ` [PATCH v4 03/14] commit-graph: rename commit_compare to oid_compare Derrick Stolee via GitGitGadget
2019-06-06 14:15       ` [PATCH v4 04/14] commit-graph: load commit-graph chains Derrick Stolee via GitGitGadget
2019-06-06 22:20         ` Junio C Hamano
2019-06-07 12:53           ` Derrick Stolee
2019-06-06 14:15       ` [PATCH v4 05/14] commit-graph: add base graphs chunk Derrick Stolee via GitGitGadget
2019-06-07 18:15         ` Junio C Hamano
2019-06-06 14:15       ` [PATCH v4 06/14] commit-graph: rearrange chunk count logic Derrick Stolee via GitGitGadget
2019-06-07 18:23         ` Junio C Hamano
2019-06-06 14:15       ` [PATCH v4 07/14] commit-graph: write commit-graph chains Derrick Stolee via GitGitGadget
2019-06-06 14:15       ` [PATCH v4 08/14] commit-graph: add --split option to builtin Derrick Stolee via GitGitGadget
2019-06-07 21:57         ` Junio C Hamano
2019-06-11 12:51           ` Derrick Stolee
2019-06-11 19:45             ` Junio C Hamano
2019-06-06 14:15       ` [PATCH v4 09/14] commit-graph: merge commit-graph chains Derrick Stolee via GitGitGadget
2019-06-06 14:15       ` [PATCH v4 10/14] commit-graph: allow cross-alternate chains Derrick Stolee via GitGitGadget
2019-06-06 17:00         ` Philip Oakley
2019-06-06 14:15       ` [PATCH v4 11/14] commit-graph: expire commit-graph files Derrick Stolee via GitGitGadget
2019-06-06 14:15       ` [PATCH v4 12/14] commit-graph: create options for split files Derrick Stolee via GitGitGadget
2019-06-06 18:41         ` Ramsay Jones
2019-06-06 14:15       ` [PATCH v4 13/14] commit-graph: verify chains with --shallow mode Derrick Stolee via GitGitGadget
2019-06-06 14:15       ` [PATCH v4 14/14] commit-graph: clean up chains after flattened write Derrick Stolee via GitGitGadget
2019-06-06 16:57       ` [PATCH v4 00/14] Commit-graph: Write incremental files Junio C Hamano
2019-06-07 12:37         ` Derrick Stolee
2019-06-07 18:38       ` [PATCH v5 00/16] " Derrick Stolee via GitGitGadget
2019-06-07 18:38         ` [PATCH v5 01/16] commit-graph: document commit-graph chains Derrick Stolee via GitGitGadget
2019-06-07 18:38         ` [PATCH v5 02/16] commit-graph: prepare for " Derrick Stolee via GitGitGadget
2019-06-07 18:38         ` [PATCH v5 03/16] commit-graph: rename commit_compare to oid_compare Derrick Stolee via GitGitGadget
2019-06-07 18:38         ` [PATCH v5 04/16] commit-graph: load commit-graph chains Derrick Stolee via GitGitGadget
2019-06-10 21:47           ` Junio C Hamano
2019-06-10 23:41             ` Derrick Stolee
2019-06-07 18:38         ` [PATCH v5 05/16] commit-graph: add base graphs chunk Derrick Stolee via GitGitGadget
2019-06-07 18:38         ` [PATCH v5 07/16] commit-graph: write commit-graph chains Derrick Stolee via GitGitGadget
2019-06-07 18:38         ` [PATCH v5 06/16] commit-graph: rearrange chunk count logic Derrick Stolee via GitGitGadget
2019-06-07 18:38         ` [PATCH v5 08/16] commit-graph: add --split option to builtin Derrick Stolee via GitGitGadget
2019-06-07 18:38         ` [PATCH v5 09/16] commit-graph: merge commit-graph chains Derrick Stolee via GitGitGadget
2019-06-07 18:38         ` [PATCH v5 10/16] commit-graph: allow cross-alternate chains Derrick Stolee via GitGitGadget
2019-06-07 18:38         ` [PATCH v5 11/16] commit-graph: expire commit-graph files Derrick Stolee via GitGitGadget
2019-06-07 18:38         ` [PATCH v5 12/16] commit-graph: create options for split files Derrick Stolee via GitGitGadget
2019-06-07 18:38         ` [PATCH v5 13/16] commit-graph: verify chains with --shallow mode Derrick Stolee via GitGitGadget
2019-06-07 18:38         ` [PATCH v5 14/16] commit-graph: clean up chains after flattened write Derrick Stolee via GitGitGadget
2019-06-07 18:38         ` [PATCH v5 15/16] commit-graph: test octopus merges with --split Derrick Stolee via GitGitGadget
2019-06-07 18:38         ` [PATCH v5 16/16] commit-graph: test --split across alternate without --split Derrick Stolee via GitGitGadget
2019-06-17 15:02         ` [PATCH] commit-graph: normalize commit-graph filenames Derrick Stolee
2019-06-17 15:07           ` Derrick Stolee
2019-06-17 18:07           ` [PATCH v2] " Derrick Stolee
2019-06-18 18:14         ` [PATCH v6 00/18] Commit-graph: Write incremental files Derrick Stolee via GitGitGadget
2019-06-18 18:14           ` [PATCH v6 01/18] commit-graph: document commit-graph chains Derrick Stolee via GitGitGadget
2019-06-18 18:14           ` [PATCH v6 03/18] commit-graph: rename commit_compare to oid_compare Derrick Stolee via GitGitGadget
2019-06-18 18:14           ` Derrick Stolee via GitGitGadget [this message]
2019-06-18 18:14           ` [PATCH v6 04/18] commit-graph: load commit-graph chains Derrick Stolee via GitGitGadget
2019-06-18 18:14           ` [PATCH v6 05/18] commit-graph: add base graphs chunk Derrick Stolee via GitGitGadget
2019-06-18 18:14           ` [PATCH v6 07/18] commit-graph: write commit-graph chains Derrick Stolee via GitGitGadget
2019-06-18 18:14           ` [PATCH v6 06/18] commit-graph: rearrange chunk count logic Derrick Stolee via GitGitGadget
2019-06-18 18:14           ` [PATCH v6 08/18] commit-graph: add --split option to builtin Derrick Stolee via GitGitGadget
2019-06-18 18:14           ` [PATCH v6 09/18] commit-graph: merge commit-graph chains Derrick Stolee via GitGitGadget
2019-06-18 18:14           ` [PATCH v6 10/18] commit-graph: allow cross-alternate chains Derrick Stolee via GitGitGadget
2019-06-18 18:14           ` [PATCH v6 11/18] commit-graph: expire commit-graph files Derrick Stolee via GitGitGadget
2019-06-18 18:14           ` [PATCH v6 13/18] commit-graph: verify chains with --shallow mode Derrick Stolee via GitGitGadget
2019-06-18 18:14           ` [PATCH v6 12/18] commit-graph: create options for split files Derrick Stolee via GitGitGadget
2019-06-18 18:14           ` [PATCH v6 14/18] commit-graph: clean up chains after flattened write Derrick Stolee via GitGitGadget
2019-06-18 18:14           ` [PATCH v6 15/18] commit-graph: test octopus merges with --split Derrick Stolee via GitGitGadget
2019-06-18 18:14           ` [PATCH v6 16/18] commit-graph: test --split across alternate without --split Derrick Stolee via GitGitGadget
2019-06-18 18:14           ` [PATCH v6 18/18] commit-graph: test verify across alternates Derrick Stolee via GitGitGadget
2019-06-18 18:14           ` [PATCH v6 17/18] commit-graph: normalize commit-graph filenames Derrick Stolee via GitGitGadget

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