From 2a2e32bdc5a80221981939e77643cec3462b4793 Mon Sep 17 00:00:00 2001 From: Derrick Stolee Date: Tue, 10 Apr 2018 08:56:02 -0400 Subject: 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 Signed-off-by: Junio C Hamano --- commit-graph.c | 137 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 136 insertions(+), 1 deletion(-) (limited to 'commit-graph.c') diff --git a/commit-graph.c b/commit-graph.c index f3f7c4f189..b1bd3a892d 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) -- cgit v1.2.1