[PATCH v4 06/13] commit-graph: implement git commit-graph read
- From
Derrick Stolee <stolee@gmail.com>
- Date
- Feb 19, 2018, 18:53 UTC
- Message-ID
- <1519066406-81663-7-git-send-email-dstolee@microsoft.com>
- In-Reply-To
- <1519066406-81663-1-git-send-email-dstolee@microsoft.com>
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> --- Documentation/git-commit-graph.txt | 15 +++++ builtin/commit-graph.c | 63 ++++++++++++++++++++ commit-graph.c | 116 +++++++++++++++++++++++++++++++++++++ commit-graph.h | 21 +++++++ t/t5318-commit-graph.sh | 38 ++++++++++-- 5 files changed, 249 insertions(+), 4 deletions(-)
diff --git a/Documentation/git-commit-graph.txt b/Documentation/git-commit-graph.txt index c3f222f..6d26e56 100644 --- a/Documentation/git-commit-graph.txt +++ b/Documentation/git-commit-graph.txt @@ -9,6 +9,7 @@ git-commit-graph - Write and verify Git commit graphs (.graph files) SYNOPSIS -------- [verse] +'git commit-graph read' <options> [--object-dir <dir>] 'git commit-graph write' <options> [--object-dir <dir>] @@ -34,6 +35,14 @@ Write a commit graph file based on the commits found in packfiles. Includes all commits from the existing commit graph file. Outputs the resulting filename. +'read':: + +Read a graph file given by the graph-head file and output basic +details about the graph file. ++ +With `--file=<name>` option, consider the graph stored in the file at +the path <object-dir>/info/<name>. + EXAMPLES -------- @@ -44,6 +53,12 @@ EXAMPLES $ git commit-graph write ------------------------------------------------ +* Read basic information from a graph file. ++ +------------------------------------------------ +$ git commit-graph read --file=<name> +------------------------------------------------ + GIT --- diff --git a/builtin/commit-graph.c b/builtin/commit-graph.c index a51d87b..28cd097 100644 --- a/builtin/commit-graph.c +++ b/builtin/commit-graph.c @@ -7,10 +7,16 @@ static char const * const builtin_commit_graph_usage[] = { N_("git commit-graph [--object-dir <objdir>]"), + N_("git commit-graph read [--object-dir <objdir>] [--file=<hash>]"), N_("git commit-graph write [--object-dir <objdir>]"), NULL }; +static const char * const builtin_commit_graph_read_usage[] = { + N_("git commit-graph read [--object-dir <objdir>] [--file=<hash>]"), + NULL +}; + static const char * const builtin_commit_graph_write_usage[] = { N_("git commit-graph write [--object-dir <objdir>]"), NULL @@ -18,8 +24,63 @@ static const char * const builtin_commit_graph_write_usage[] = { static struct opts_commit_graph { const char *obj_dir; + const char *graph_file; } opts; +static int graph_read(int argc, const char **argv) +{ + struct commit_graph *graph = 0; + struct strbuf full_path = STRBUF_INIT; + + static struct option builtin_commit_graph_read_options[] = { + { OPTION_STRING, 'o', "object-dir", &opts.obj_dir, + N_("dir"), + N_("The object directory to store the graph") }, + { OPTION_STRING, 'H', "file", &opts.graph_file, + N_("file"), + N_("The filename for a specific commit graph file in the object directory."), + PARSE_OPT_OPTARG, NULL, (intptr_t) "" }, + OPT_END(), + }; + + argc = parse_options(argc, argv, NULL, + builtin_commit_graph_read_options, + builtin_commit_graph_read_usage, 0); + + if (!opts.obj_dir) + opts.obj_dir = get_object_directory(); + + if (!opts.graph_file) + die("no graph hash specified"); + + strbuf_addf(&full_path, "%s/info/%s", opts.obj_dir, opts.graph_file); + graph = load_commit_graph_one(full_path.buf); + + if (!graph) + die("graph file %s does not exist", full_path.buf); + + printf("header: %08x %d %d %d %d\n", + ntohl(*(uint32_t*)graph->data), + *(unsigned char*)(graph->data + 4), + *(unsigned char*)(graph->data + 5), + *(unsigned char*)(graph->data + 6), + *(unsigned char*)(graph->data + 7)); + printf("num_commits: %u\n", graph->num_commits); + printf("chunks:"); + + if (graph->chunk_oid_fanout) + printf(" oid_fanout"); + if (graph->chunk_oid_lookup) + printf(" oid_lookup"); + if (graph->chunk_commit_data) + printf(" commit_metadata"); + if (graph->chunk_large_edges) + printf(" large_edges"); + printf("\n"); + + return 0; +} + static int graph_write(int argc, const char **argv) { char *graph_name; @@ -68,6 +129,8 @@ int cmd_commit_graph(int argc, const char **argv, const char *prefix) PARSE_OPT_STOP_AT_NON_OPTION); if (argc > 0) { + if (!strcmp(argv[0], "read")) + return graph_read(argc, argv); if (!strcmp(argv[0], "write")) return graph_write(argc, argv); } diff --git a/commit-graph.c b/commit-graph.c index f9e39b0..2a8594f 100644 --- a/commit-graph.c +++ b/commit-graph.c @@ -38,6 +38,122 @@ #define GRAPH_MIN_SIZE (GRAPH_CHUNKLOOKUP_SIZE + GRAPH_FANOUT_SIZE + \ GRAPH_OID_LEN + 8) +static struct commit_graph *alloc_commit_graph(void) +{ + struct commit_graph *g = xmalloc(sizeof(*g)); + memset(g, 0, 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 0; + if (fstat(fd, &st)) { + close(fd); + return 0; + } + 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 = ntohl(*(uint32_t*)data); + if (graph_signature != GRAPH_SIGNATURE) { + munmap(graph_map, graph_size); + close(fd); + die("graph signature %X does not match signature %X", + graph_signature, GRAPH_SIGNATURE); + } + + graph_version = *(unsigned char*)(data + 4); + if (graph_version != GRAPH_VERSION) { + munmap(graph_map, graph_size); + close(fd); + die("graph version %X does not match version %X", + graph_version, GRAPH_VERSION); + } + + hash_version = *(unsigned char*)(data + 5); + if (hash_version != GRAPH_OID_VERSION) { + munmap(graph_map, graph_size); + close(fd); + die("hash version %X does not match version %X", + hash_version, GRAPH_OID_VERSION); + } + + 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_offset1 = get_be32(chunk_lookup + 4); + uint32_t chunk_offset2 = get_be32(chunk_lookup + 8); + uint64_t chunk_offset = (chunk_offset1 << 32) | chunk_offset2; + + chunk_lookup += GRAPH_CHUNKLOOKUP_WIDTH; + + if (chunk_offset > graph_size - GIT_MAX_RAWSZ) + die("improper chunk offset %08x%08x", (uint32_t)(chunk_offset >> 32), + (uint32_t)chunk_offset); + + switch (chunk_id) { + case GRAPH_CHUNKID_OIDFANOUT: + graph->chunk_oid_fanout = (uint32_t*)(data + chunk_offset); + break; + + case GRAPH_CHUNKID_OIDLOOKUP: + graph->chunk_oid_lookup = data + chunk_offset; + break; + + case GRAPH_CHUNKID_DATA: + graph->chunk_commit_data = data + chunk_offset; + break; + + case GRAPH_CHUNKID_LARGEEDGES: + graph->chunk_large_edges = data + chunk_offset; + break; + } + + 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; +} + static void write_graph_chunk_fanout(struct sha1file *f, struct commit **commits, int nr_commits) diff --git a/commit-graph.h b/commit-graph.h index dc8c73a..9093b97 100644 --- a/commit-graph.h +++ b/commit-graph.h @@ -1,6 +1,27 @@ #ifndef COMMIT_GRAPH_H #define COMMIT_GRAPH_H +#include "git-compat-util.h" + +struct commit_graph { + int graph_fd; + + const unsigned char *data; + size_t data_len; + + unsigned char hash_len; + unsigned char num_chunks; + uint32_t num_commits; + struct object_id oid; + + const uint32_t *chunk_oid_fanout; + const unsigned char *chunk_oid_lookup; + const unsigned char *chunk_commit_data; + const unsigned char *chunk_large_edges; +}; + +extern struct commit_graph *load_commit_graph_one(const char *graph_file); + extern char *write_commit_graph(const char *obj_dir); #endif diff --git a/t/t5318-commit-graph.sh b/t/t5318-commit-graph.sh index 6a5e93c..893fa24 100755 --- a/t/t5318-commit-graph.sh +++ b/t/t5318-commit-graph.sh @@ -24,9 +24,27 @@ test_expect_success 'create commits and repack' ' git repack ' +graph_read_expect() { + OPTIONAL="" + NUM_CHUNKS=3 + if [ ! -z $2 ] + then + OPTIONAL=" $2" + NUM_CHUNKS=$((3 + $(echo "$2" | wc -w))) + fi + cat >expect <<- EOF + header: 43475048 1 1 $NUM_CHUNKS 0 + num_commits: $1 + chunks: oid_fanout oid_lookup commit_metadata$OPTIONAL + EOF +} + test_expect_success 'write graph' ' graph1=$(git commit-graph write) && - test_path_is_file $objdir/info/$graph1 + test_path_is_file $objdir/info/$graph1 && + git commit-graph read --file=$graph1 >output && + graph_read_expect "3" && + test_cmp expect output ' test_expect_success 'Add more commits' ' @@ -67,7 +85,10 @@ test_expect_success 'Add more commits' ' test_expect_success 'write graph with merges' ' graph2=$(git commit-graph write)&& - test_path_is_file $objdir/info/$graph2 + test_path_is_file $objdir/info/$graph2 && + git commit-graph read --file=$graph2 >output && + graph_read_expect "10" "large_edges" && + test_cmp expect output ' test_expect_success 'Add one more commit' ' @@ -92,7 +113,10 @@ test_expect_success 'Add one more commit' ' test_expect_success 'write graph with new commit' ' graph3=$(git commit-graph write) && - test_path_is_file $objdir/info/$graph3 + test_path_is_file $objdir/info/$graph3 && + git commit-graph read --file=$graph3 >output && + graph_read_expect "11" "large_edges" && + test_cmp expect output ' test_expect_success 'write graph with nothing new' ' @@ -100,6 +124,9 @@ test_expect_success 'write graph with nothing new' ' test_path_is_file $objdir/info/$graph4 && printf $graph3 >expect && printf $graph4 >output && + test_cmp expect output && + git commit-graph read --file=$graph4 >output && + graph_read_expect "11" "large_edges" && test_cmp expect output ' @@ -112,7 +139,10 @@ test_expect_success 'setup bare repo' ' test_expect_success 'write graph in bare repo' ' graphbare=$(git commit-graph write) && - test_path_is_file $baredir/info/$graphbare + test_path_is_file $baredir/info/$graphbare && + git commit-graph read --file=$graphbare >output && + graph_read_expect "11" "large_edges" && + test_cmp expect output ' test_done
-- 2.7.4