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authorDerrick Stolee <dstolee@microsoft.com>2018-04-10 12:56:02 (GMT)
committerJunio C Hamano <gitster@pobox.com>2018-04-11 01:43:01 (GMT)
commit2a2e32bdc5a80221981939e77643cec3462b4793 (patch)
treeae0344a998a46747dec3fbaf443e852ae4f71db4 /commit-graph.c
parentf237c8b6feaa3bad352bd27c14f0d83d0a1c061a (diff)
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commit-graph: implement git commit-graph read
Teach git-commit-graph to read commit graph files and summarize their contents. Use the read subcommand to verify the contents of a commit graph file in the tests. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'commit-graph.c')
-rw-r--r--commit-graph.c137
1 files changed, 136 insertions, 1 deletions
diff --git a/commit-graph.c b/commit-graph.c
index f3f7c4f..b1bd3a8 100644
--- a/commit-graph.c
+++ b/commit-graph.c
@@ -39,11 +39,146 @@
GRAPH_OID_LEN + 8)
-static char *get_commit_graph_filename(const char *obj_dir)
+char *get_commit_graph_filename(const char *obj_dir)
{
return xstrfmt("%s/info/commit-graph", obj_dir);
}
+static struct commit_graph *alloc_commit_graph(void)
+{
+ struct commit_graph *g = xcalloc(1, sizeof(*g));
+ g->graph_fd = -1;
+
+ return g;
+}
+
+struct commit_graph *load_commit_graph_one(const char *graph_file)
+{
+ void *graph_map;
+ const unsigned char *data, *chunk_lookup;
+ size_t graph_size;
+ struct stat st;
+ uint32_t i;
+ struct commit_graph *graph;
+ int fd = git_open(graph_file);
+ uint64_t last_chunk_offset;
+ uint32_t last_chunk_id;
+ uint32_t graph_signature;
+ unsigned char graph_version, hash_version;
+
+ if (fd < 0)
+ return NULL;
+ if (fstat(fd, &st)) {
+ close(fd);
+ return NULL;
+ }
+ graph_size = xsize_t(st.st_size);
+
+ if (graph_size < GRAPH_MIN_SIZE) {
+ close(fd);
+ die("graph file %s is too small", graph_file);
+ }
+ graph_map = xmmap(NULL, graph_size, PROT_READ, MAP_PRIVATE, fd, 0);
+ data = (const unsigned char *)graph_map;
+
+ graph_signature = get_be32(data);
+ if (graph_signature != GRAPH_SIGNATURE) {
+ error("graph signature %X does not match signature %X",
+ graph_signature, GRAPH_SIGNATURE);
+ goto cleanup_fail;
+ }
+
+ graph_version = *(unsigned char*)(data + 4);
+ if (graph_version != GRAPH_VERSION) {
+ error("graph version %X does not match version %X",
+ graph_version, GRAPH_VERSION);
+ goto cleanup_fail;
+ }
+
+ hash_version = *(unsigned char*)(data + 5);
+ if (hash_version != GRAPH_OID_VERSION) {
+ error("hash version %X does not match version %X",
+ hash_version, GRAPH_OID_VERSION);
+ goto cleanup_fail;
+ }
+
+ graph = alloc_commit_graph();
+
+ graph->hash_len = GRAPH_OID_LEN;
+ graph->num_chunks = *(unsigned char*)(data + 6);
+ graph->graph_fd = fd;
+ graph->data = graph_map;
+ graph->data_len = graph_size;
+
+ last_chunk_id = 0;
+ last_chunk_offset = 8;
+ chunk_lookup = data + 8;
+ for (i = 0; i < graph->num_chunks; i++) {
+ uint32_t chunk_id = get_be32(chunk_lookup + 0);
+ uint64_t chunk_offset = get_be64(chunk_lookup + 4);
+ int chunk_repeated = 0;
+
+ chunk_lookup += GRAPH_CHUNKLOOKUP_WIDTH;
+
+ if (chunk_offset > graph_size - GIT_MAX_RAWSZ) {
+ error("improper chunk offset %08x%08x", (uint32_t)(chunk_offset >> 32),
+ (uint32_t)chunk_offset);
+ goto cleanup_fail;
+ }
+
+ switch (chunk_id) {
+ case GRAPH_CHUNKID_OIDFANOUT:
+ if (graph->chunk_oid_fanout)
+ chunk_repeated = 1;
+ else
+ graph->chunk_oid_fanout = (uint32_t*)(data + chunk_offset);
+ break;
+
+ case GRAPH_CHUNKID_OIDLOOKUP:
+ if (graph->chunk_oid_lookup)
+ chunk_repeated = 1;
+ else
+ graph->chunk_oid_lookup = data + chunk_offset;
+ break;
+
+ case GRAPH_CHUNKID_DATA:
+ if (graph->chunk_commit_data)
+ chunk_repeated = 1;
+ else
+ graph->chunk_commit_data = data + chunk_offset;
+ break;
+
+ case GRAPH_CHUNKID_LARGEEDGES:
+ if (graph->chunk_large_edges)
+ chunk_repeated = 1;
+ else
+ graph->chunk_large_edges = data + chunk_offset;
+ break;
+ }
+
+ if (chunk_repeated) {
+ error("chunk id %08x appears multiple times", chunk_id);
+ goto cleanup_fail;
+ }
+
+ if (last_chunk_id == GRAPH_CHUNKID_OIDLOOKUP)
+ {
+ graph->num_commits = (chunk_offset - last_chunk_offset)
+ / graph->hash_len;
+ }
+
+ last_chunk_id = chunk_id;
+ last_chunk_offset = chunk_offset;
+ }
+
+ return graph;
+
+cleanup_fail:
+ munmap(graph_map, graph_size);
+ close(fd);
+ exit(1);
+}
+
static void write_graph_chunk_fanout(struct hashfile *f,
struct commit **commits,
int nr_commits)