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 <dsto...@microsoft.com>
---
Documentation/git-commit-graph.txt | 16 ++++
builtin/commit-graph.c | 71 ++++++++++++++++++
commit-graph.c | 147 +++++++++++++++++++++++++++++++++++++
commit-graph.h | 23 ++++++
t/t5318-commit-graph.sh | 34 +++++++--
5 files changed, 286 insertions(+), 5 deletions(-)
diff --git a/Documentation/git-commit-graph.txt
b/Documentation/git-commit-graph.txt
index 55dfe5c3d8..67e107f06a 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> [--pack-dir <pack_dir>]
'git commit-graph write' <options> [--pack-dir <pack_dir>]
@@ -34,6 +35,15 @@ Includes all commits from the existing commit graph file.
Outputs the
checksum hash of the written file.
+'read'::
+
+Read a graph file given by the graph-head file and output basic
+details about the graph file.
++
+With `--graph-hash=<hash>` option, consider the graph file
+graph-<hash>.graph in the pack directory.
+
+
EXAMPLES
--------
@@ -43,6 +53,12 @@ EXAMPLES
$ git commit-graph write
------------------------------------------------
+* Read basic information from a graph file.
++
+------------------------------------------------
+$ git commit-graph read --graph-hash=<hash>
+------------------------------------------------
+
GIT
---
diff --git a/builtin/commit-graph.c b/builtin/commit-graph.c
index 5dac033bfe..3ffa7ec433 100644
--- a/builtin/commit-graph.c
+++ b/builtin/commit-graph.c
@@ -5,10 +5,16 @@
static char const * const builtin_commit_graph_usage[] = {
N_("git commit-graph [--pack-dir <packdir>]"),
+ N_("git commit-graph read [--graph-hash=<hash>]"),
N_("git commit-graph write [--pack-dir <packdir>]"),
NULL
};
+static const char * const builtin_commit_graph_read_usage[] = {
+ N_("git commit-graph read [--pack-dir <packdir>]"),
+ NULL
+};
+
static const char * const builtin_commit_graph_write_usage[] = {
N_("git commit-graph write [--pack-dir <packdir>]"),
NULL
@@ -16,8 +22,71 @@ static const char * const builtin_commit_graph_write_usage[]
= {
static struct opts_commit_graph {
const char *pack_dir;
+ const char *graph_hash;
} opts;
+static int graph_read(int argc, const char **argv)
+{
+ struct object_id graph_hash;
+ struct commit_graph *graph = 0;
+ const char *graph_file;
+
+ static struct option builtin_commit_graph_read_options[] = {
+ { OPTION_STRING, 'p', "pack-dir", &opts.pack_dir,
+ N_("dir"),
+ N_("The pack directory to store the graph") },
+ { OPTION_STRING, 'H', "graph-hash", &opts.graph_hash,
+ N_("hash"),
+ N_("A hash for a specific graph file in the pack-dir."),
+ 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.pack_dir) {
+ struct strbuf path = STRBUF_INIT;
+ strbuf_addstr(&path, get_object_directory());
+ strbuf_addstr(&path, "/pack");
+ opts.pack_dir = strbuf_detach(&path, NULL);
+ }
+
+ if (opts.graph_hash && strlen(opts.graph_hash) == GIT_MAX_HEXSZ)
+ get_oid_hex(opts.graph_hash, &graph_hash);
+ else
+ die("no graph hash specified");
+
+ graph_file = get_commit_graph_filename_hash(opts.pack_dir, &graph_hash);
+ graph = load_commit_graph_one(graph_file, opts.pack_dir);
+
+ if (!graph)
+ die("graph file %s does not exist", graph_file);
+
+ printf("header: %08x %02x %02x %02x %02x\n",
+ ntohl(*(uint32_t*)graph->data),
+ *(unsigned char*)(graph->data + 4),
+ *(unsigned char*)(graph->data + 5),
+ graph->hash_len,
+ graph->num_chunks);
+ 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");
+
+ printf("pack_dir: %s\n", graph->pack_dir);
+ return 0;
+}
+
static int graph_write(int argc, const char **argv)
{
struct object_id *graph_hash;
@@ -70,6 +139,8 @@ 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 cb47b68871..9a337cea4d 100644
--- a/commit-graph.c
+++ b/commit-graph.c
@@ -51,6 +51,153 @@ char* get_commit_graph_filename_hash(const char *pack_dir,
return strbuf_detach(&path, &len);
}
+static struct commit_graph *alloc_commit_graph(int extra)
+{
+ struct commit_graph *g = xmalloc(st_add(sizeof(*g), extra));
+ memset(g, 0, sizeof(*g));
+ g->graph_fd = -1;
+
+ return g;
+}
+
+static int close_commit_graph(struct commit_graph *g)
+{
+ if (g->graph_fd < 0)
+ return 0;
+
+ munmap((void *)g->data, g->data_len);
+ g->data = 0;
+
+ close(g->graph_fd);
+ g->graph_fd = -1;
+
+ return 1;
+}
+
+static void free_commit_graph(struct commit_graph **g)
+{
+ if (!g || !*g)
+ return;
+
+ close_commit_graph(*g);
+ FREE_AND_NULL(*g);
+}
+
+struct commit_graph *load_commit_graph_one(const char *graph_file, const char
*pack_dir)
+{
+ 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(strlen(pack_dir) + 1);
+
+ graph->hash_len = *(unsigned char*)(data + 6);
+ graph->num_chunks = *(unsigned char*)(data + 7);
+ 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 = 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;
+
+ case 0:
+ break;
+
+ default:
+ free_commit_graph(&graph);
+ die("unrecognized graph chunk id: %08x",
chunk_id);
+ }
+
+ 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;
+ }
+
+ strcpy(graph->pack_dir, pack_dir);
+ 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 4756f6ba5b..c1608976b3 100644
--- a/commit-graph.h
+++ b/commit-graph.h
@@ -7,6 +7,29 @@
extern char* get_commit_graph_filename_hash(const char *pack_dir,
struct object_id *hash);
+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 unsigned char *chunk_oid_fanout;
+ const unsigned char *chunk_oid_lookup;
+ const unsigned char *chunk_commit_data;
+ const unsigned char *chunk_large_edges;
+
+ /* something like ".git/objects/pack" */
+ char pack_dir[FLEX_ARRAY]; /* more */
+};
+
+extern struct commit_graph *load_commit_graph_one(const char *graph_file,
+ const char *pack_dir);
+
extern struct object_id *write_commit_graph(const char *pack_dir);
#endif
diff --git a/t/t5318-commit-graph.sh b/t/t5318-commit-graph.sh
index b762587595..ad1d0e621d 100755
--- a/t/t5318-commit-graph.sh
+++ b/t/t5318-commit-graph.sh
@@ -21,9 +21,21 @@ test_expect_success 'create commits and repack' '
done &&
git repack'
+graph_read_expect() {
+ cat >expect <<- EOF
+ header: 43475048 01 01 14 04
+ num_commits: $1
+ chunks: oid_fanout oid_lookup commit_metadata large_edges
+ pack_dir: $2
+ EOF
+}
+
test_expect_success 'write graph' '
graph1=$(git commit-graph write) &&
- test_path_is_file $packdir/graph-$graph1.graph'
+ test_path_is_file $packdir/graph-$graph1.graph &&
+ git commit-graph read --graph-hash=$graph1 >output &&
+ graph_read_expect "3" "$packdir" &&
+ test_cmp expect output'
test_expect_success 'Add more commits' '
git reset --hard commits/1 &&
@@ -62,7 +74,10 @@ test_expect_success 'Add more commits' '
test_expect_success 'write graph with merges' '
graph2=$(git commit-graph write)&&
- test_path_is_file $packdir/graph-$graph2.graph'
+ test_path_is_file $packdir/graph-$graph2.graph &&
+ git commit-graph read --graph-hash=$graph2 >output &&
+ graph_read_expect "10" "$packdir" &&
+ test_cmp expect output'
test_expect_success 'Add one more commit' '
test_commit 8 &&
@@ -85,14 +100,20 @@ test_expect_success 'Add one more commit' '
test_expect_success 'write graph with new commit' '
graph3=$(git commit-graph write) &&
- test_path_is_file $packdir/graph-$graph3.graph'
-
+ test_path_is_file $packdir/graph-$graph3.graph &&
+ test_path_is_file $packdir/graph-$graph3.graph &&
+ git commit-graph read --graph-hash=$graph3 >output &&
+ graph_read_expect "11" "$packdir" &&
+ test_cmp expect output'
test_expect_success 'write graph with nothing new' '
graph4=$(git commit-graph write) &&
test_path_is_file $packdir/graph-$graph4.graph &&
printf $graph3 >expect &&
printf $graph4 >output &&
+ test_cmp expect output &&
+ git commit-graph read --graph-hash=$graph4 >output &&
+ graph_read_expect "11" "$packdir" &&
test_cmp expect output'
test_expect_success 'setup bare repo' '
@@ -103,7 +124,10 @@ test_expect_success 'setup bare repo' '
test_expect_success 'write graph in bare repo' '
graphbare=$(git commit-graph write) &&
- test_path_is_file $baredir/graph-$graphbare.graph'
+ test_path_is_file $baredir/graph-$graphbare.graph &&
+ git commit-graph read --graph-hash=$graphbare >output &&
+ graph_read_expect "11" "$baredir" &&
+ test_cmp expect output'
test_done
--
2.15.1.45.g9b7079f
