git/list[1] front-page[2] threads[3] people[4] search[5] about
 

[RFC PATCH 08/12] commit-graph: convert to using the_hash_algo

From
brian m. carlson <sandals@crustytoothpaste.net>
Date
Aug 29, 2018, 00:58 UTC
Message-ID
<20180829005857.980820-9-sandals@crustytoothpaste.net>
In-Reply-To
<20180829005857.980820-1-sandals@crustytoothpaste.net>

Instead of using hard-coded constants for object sizes, use the_hash_algo to look them up. In addition, use a function call to look up the object ID version and produce the correct value.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
---
 commit-graph.c | 31 ++++++++++++++++---------------
 1 file changed, 16 insertions(+), 15 deletions(-)
diff --git a/commit-graph.c b/commit-graph.c
index 8a1bec7b8a..29356d84a2 100644
--- a/commit-graph.c
+++ b/commit-graph.c
@@ -25,11 +25,6 @@
 #define GRAPH_VERSION_1 0x1
 #define GRAPH_VERSION GRAPH_VERSION_1
 
-#define GRAPH_OID_VERSION_SHA1 1
-#define GRAPH_OID_LEN_SHA1 GIT_SHA1_RAWSZ
-#define GRAPH_OID_VERSION GRAPH_OID_VERSION_SHA1
-#define GRAPH_OID_LEN GRAPH_OID_LEN_SHA1
-
 #define GRAPH_OCTOPUS_EDGES_NEEDED 0x80000000
 #define GRAPH_PARENT_MISSING 0x7fffffff
 #define GRAPH_EDGE_LAST_MASK 0x7fffffff
@@ -41,13 +36,18 @@
 #define GRAPH_FANOUT_SIZE (4 * 256)
 #define GRAPH_CHUNKLOOKUP_WIDTH 12
 #define GRAPH_MIN_SIZE (GRAPH_HEADER_SIZE + 4 * GRAPH_CHUNKLOOKUP_WIDTH \
-			+ GRAPH_FANOUT_SIZE + GRAPH_OID_LEN)
+			+ GRAPH_FANOUT_SIZE + the_hash_algo->rawsz)
 
 char *get_commit_graph_filename(const char *obj_dir)
 {
 	return xstrfmt("%s/info/commit-graph", obj_dir);
 }
 
+static uint8_t oid_version(void)
+{
+	return 1;
+}
+
 static struct commit_graph *alloc_commit_graph(void)
 {
 	struct commit_graph *g = xcalloc(1, sizeof(*g));
@@ -100,15 +100,15 @@ struct commit_graph *load_commit_graph_one(const char *graph_file)
 	}
 
 	hash_version = *(unsigned char*)(data + 5);
-	if (hash_version != GRAPH_OID_VERSION) {
+	if (hash_version != oid_version()) {
 		error(_("hash version %X does not match version %X"),
-		      hash_version, GRAPH_OID_VERSION);
+		      hash_version, oid_version());
 		goto cleanup_fail;
 	}
 
 	graph = alloc_commit_graph();
 
-	graph->hash_len = GRAPH_OID_LEN;
+	graph->hash_len = the_hash_algo->rawsz;
 	graph->num_chunks = *(unsigned char*)(data + 6);
 	graph->graph_fd = fd;
 	graph->data = graph_map;
@@ -124,7 +124,7 @@ struct commit_graph *load_commit_graph_one(const char *graph_file)
 
 		chunk_lookup += GRAPH_CHUNKLOOKUP_WIDTH;
 
-		if (chunk_offset > graph_size - GIT_MAX_RAWSZ) {
+		if (chunk_offset > graph_size - the_hash_algo->rawsz) {
 			error(_("improper chunk offset %08x%08x"), (uint32_t)(chunk_offset >> 32),
 			      (uint32_t)chunk_offset);
 			goto cleanup_fail;
@@ -692,6 +692,7 @@ void write_commit_graph(const char *obj_dir,
 	int num_chunks;
 	int num_extra_edges;
 	struct commit_list *parent;
+	const unsigned hashsz = the_hash_algo->rawsz;
 
 	oids.nr = 0;
 	oids.alloc = approximate_object_count() / 4;
@@ -812,7 +813,7 @@ void write_commit_graph(const char *obj_dir,
 	hashwrite_be32(f, GRAPH_SIGNATURE);
 
 	hashwrite_u8(f, GRAPH_VERSION);
-	hashwrite_u8(f, GRAPH_OID_VERSION);
+	hashwrite_u8(f, oid_version());
 	hashwrite_u8(f, num_chunks);
 	hashwrite_u8(f, 0); /* unused padding byte */
 
@@ -827,8 +828,8 @@ void write_commit_graph(const char *obj_dir,
 
 	chunk_offsets[0] = 8 + (num_chunks + 1) * GRAPH_CHUNKLOOKUP_WIDTH;
 	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[2] = chunk_offsets[1] + hashsz * commits.nr;
+	chunk_offsets[3] = chunk_offsets[2] + (hashsz + 16) * commits.nr;
 	chunk_offsets[4] = chunk_offsets[3] + 4 * num_extra_edges;
 
 	for (i = 0; i <= num_chunks; i++) {
@@ -841,8 +842,8 @@ void write_commit_graph(const char *obj_dir,
 	}
 
 	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_oids(f, hashsz, commits.list, commits.nr);
+	write_graph_chunk_data(f, hashsz, commits.list, commits.nr);
 	write_graph_chunk_large_edges(f, commits.list, commits.nr);
 
 	close_commit_graph();
Previous: brian m. carlsonNext: Derrick Stolee
Message 8 of 24 in “Base SHA-256 algorithm implementation”
  1. 00/12 Base SHA-256 algorithm implementationbrian m. carlson, Aug 29, 2018
  2. 01/12 sha1-file: rename algorithm to "sha1"brian m. carlson, Aug 29, 2018
  3. 03/12 hex: introduce functions to print arbitrary hashesbrian m. carlson, Aug 29, 2018
  4. 04/12 t: add basic tests for our SHA-1 implementationbrian m. carlson, Aug 29, 2018
  5. 05/12 t: make the sha1 test-tool helper genericbrian m. carlson, Aug 29, 2018
  6. 07/12 t/helper: add a test helper to compute hash speedbrian m. carlson, Aug 29, 2018
  7. 06/12 sha1-file: add a constant for hash block sizebrian m. carlson, Aug 29, 2018
  8. 08/12 commit-graph: convert to using the_hash_algobrian m. carlson, Aug 29, 2018
  9. Derrick StoleeAug 29, 2018
  10. brian m. carlsonAug 30, 2018
  11. brian m. carlsonSep 3, 2018
  12. 09/12 Add a base implementation of SHA-256 supportbrian m. carlson, Aug 29, 2018
  13. Ævar Arnfjörð BjarmasonAug 29, 2018
  14. brian m. carlsonAug 29, 2018
  15. Derrick StoleeAug 29, 2018
  16. 10/12 sha256: add an SHA-256 implementation using libgcryptbrian m. carlson, Aug 29, 2018
  17. Ævar Arnfjörð BjarmasonAug 29, 2018
  18. brian m. carlsonAug 29, 2018
  19. 11/12 hash: add an SHA-256 implementation using OpenSSLbrian m. carlson, Aug 29, 2018
  20. 12/12 commit-graph: specify OID version for SHA-256brian m. carlson, Aug 29, 2018
  21. 02/12 sha1-file: provide functions to look up hash algorithmsbrian m. carlson, Aug 29, 2018
  22. Ævar Arnfjörð BjarmasonAug 29, 2018
  23. brian m. carlsonAug 30, 2018
  24. brian m. carlsonAug 30, 2018

Read the whole thread, see it on lore, or plain text.

$ cat FOOTERMessages come from the public archive at lore.kernel.org/git, fetched every hour. The front page is chosen and written each morning by an AI editor and can be wrong; the threads themselves are the record. About and API. For agents: an MCP server at https://gitlist.dev/mcp, and any thread, story or person page as Markdown by adding .md to its URL (or sending Accept: text/markdown). Details in /llms.txt.