Teach git-commit-graph to read commit graph files and summarize their contents.
Use the --read option 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 | 7 ++
builtin/commit-graph.c | 55 +++++++++++++++
commit-graph.c | 138 ++++++++++++++++++++++++++++++++++++-
commit-graph.h | 25 +++++++
t/t5318-commit-graph.sh | 28 ++++++--
5 files changed, 247 insertions(+), 6 deletions(-)
diff --git a/Documentation/git-commit-graph.txt
b/Documentation/git-commit-graph.txt
index 3f3790d9a8..09aeaf6c82 100644
--- a/Documentation/git-commit-graph.txt
+++ b/Documentation/git-commit-graph.txt
@@ -10,6 +10,7 @@ SYNOPSIS
--------
[verse]
'git commit-graph' --write <options> [--pack-dir <pack_dir>]
+'git commit-graph' --read <options> [--pack-dir <pack_dir>]
EXAMPLES
--------
@@ -20,6 +21,12 @@ EXAMPLES
$ git commit-graph --write
------------------------------------------------
+* Read basic information from a graph file.
++
+------------------------------------------------
+$ git commit-graph --read --graph-hash=<hash>
+------------------------------------------------
+
GIT
---
Part of the linkgit:git[1] suite
diff --git a/builtin/commit-graph.c b/builtin/commit-graph.c
index 7affd512f1..218740b1f8 100644
--- a/builtin/commit-graph.c
+++ b/builtin/commit-graph.c
@@ -10,15 +10,58 @@
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 struct opts_commit_graph {
const char *pack_dir;
+ int read;
+ const char *graph_hash;
int write;
} opts;
+static int graph_read(void)
+{
+ struct object_id graph_hash;
+ struct commit_graph *graph = 0;
+ const char *graph_file;
+
+ 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(graph->hdr->graph_signature),
+ graph->hdr->graph_version,
+ graph->hdr->hash_version,
+ graph->hdr->hash_len,
+ graph->hdr->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(void)
{
struct object_id *graph_hash = construct_commit_graph(opts.pack_dir);
@@ -36,8 +79,14 @@ int cmd_commit_graph(int argc, const char **argv, const char
*prefix)
{ OPTION_STRING, 'p', "pack-dir", &opts.pack_dir,
N_("dir"),
N_("The pack directory to store the graph") },
+ OPT_BOOL('r', "read", &opts.read,
+ N_("read graph file")),
OPT_BOOL('w', "write", &opts.write,
N_("write commit graph file")),
+ { 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(),
};
@@ -49,6 +98,10 @@ int cmd_commit_graph(int argc, const char **argv, const char
*prefix)
builtin_commit_graph_options,
builtin_commit_graph_usage, 0);
+ if (opts.write + opts.read > 1)
+ usage_with_options(builtin_commit_graph_usage,
+ builtin_commit_graph_options);
+
if (!opts.pack_dir) {
struct strbuf path = STRBUF_INIT;
strbuf_addstr(&path, get_object_directory());
@@ -56,6 +109,8 @@ int cmd_commit_graph(int argc, const char **argv, const char
*prefix)
opts.pack_dir = strbuf_detach(&path, NULL);
}
+ if (opts.read)
+ return graph_read();
if (opts.write)
return graph_write();
diff --git a/commit-graph.c b/commit-graph.c
index db2b7390c7..622a650259 100644
--- a/commit-graph.c
+++ b/commit-graph.c
@@ -48,6 +48,142 @@ char* get_commit_graph_filename_hash(const char *pack_dir,
return strbuf_detach(&head_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;
+}
+
+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(*g);
+ *g = NULL;
+}
+
+struct commit_graph *load_commit_graph_one(const char *graph_file, const char
*pack_dir)
+{
+ void *graph_map;
+ const unsigned char *data;
+ struct commit_graph_header *hdr;
+ 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;
+
+ 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;
+
+ hdr = graph_map;
+ if (ntohl(hdr->graph_signature) != GRAPH_SIGNATURE) {
+ uint32_t signature = ntohl(hdr->graph_signature);
+ munmap(graph_map, graph_size);
+ close(fd);
+ die("graph signature %X does not match signature %X",
+ signature, GRAPH_SIGNATURE);
+ }
+ if (hdr->graph_version != GRAPH_VERSION) {
+ unsigned char version = hdr->graph_version;
+ munmap(graph_map, graph_size);
+ close(fd);
+ die("graph version %X does not match version %X",
+ version, GRAPH_VERSION);
+ }
+
+ graph = alloc_commit_graph(strlen(pack_dir) + 1);
+
+ graph->hdr = hdr;
+ graph->graph_fd = fd;
+ graph->data = graph_map;
+ graph->data_len = graph_size;
+
+ last_chunk_id = 0;
+ last_chunk_offset = (uint64_t)sizeof(*hdr);
+ for (i = 0; i < hdr->num_chunks; i++) {
+ uint32_t chunk_id = ntohl(*(uint32_t*)(data + sizeof(*hdr) + 12
* i));
+ uint64_t chunk_offset1 = ntohl(*(uint32_t*)(data + sizeof(*hdr)
+ 12 * i + 4));
+ uint32_t chunk_offset2 = ntohl(*(uint32_t*)(data + sizeof(*hdr)
+ 12 * i + 8));
+ uint64_t chunk_offset = (chunk_offset1 << 32) | chunk_offset2;
+
+ 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)
+ / hdr->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)
@@ -361,7 +497,7 @@ struct object_id *construct_commit_graph(const char
*pack_dir)
sha1close(f, final_hash, CSUM_CLOSE | CSUM_FSYNC);
f_hash = (struct object_id *)malloc(sizeof(struct object_id));
- memcpy(f_hash->hash, final_hash, GIT_MAX_RAWSZ);
+ hashcpy(f_hash->hash, final_hash);
fname = get_commit_graph_filename_hash(pack_dir, f_hash);
if (rename(graph_name, fname))
diff --git a/commit-graph.h b/commit-graph.h
index 7b3469a7df..e046ae575c 100644
--- a/commit-graph.h
+++ b/commit-graph.h
@@ -15,6 +15,31 @@ struct commit_graph_header {
unsigned char num_chunks;
};
+extern struct commit_graph {
+ int graph_fd;
+
+ const unsigned char *data;
+ size_t data_len;
+
+ const struct commit_graph_header *hdr;
+
+ struct object_id oid;
+
+ uint32_t num_commits;
+
+ 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 */
+} *commit_graph;
+
+extern int close_commit_graph(struct commit_graph *g);
+
+extern struct commit_graph *load_commit_graph_one(const char *graph_file,
const char *pack_dir);
+
extern struct object_id *construct_commit_graph(const char *pack_dir);
#endif
diff --git a/t/t5318-commit-graph.sh b/t/t5318-commit-graph.sh
index 6bcd1cc264..da565624e3 100755
--- a/t/t5318-commit-graph.sh
+++ b/t/t5318-commit-graph.sh
@@ -25,11 +25,23 @@ 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=${graph1} >output &&
+ _graph_read_expect "5" "${packdir}" &&
+ cmp expect output'
-t_expect_success 'Add more commits' \
+test_expect_success 'Add more commits' \
'git reset --hard commits/3 &&
for i in $(test_seq 6 10)
do
@@ -79,7 +91,10 @@ t_expect_success 'Add more commits' \
test_expect_success 'write graph with merges' \
'graph2=$(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=${graph2} >output &&
+ _graph_read_expect "18" "${packdir}" &&
+ cmp expect output'
test_expect_success 'setup bare repo' \
'cd .. &&
@@ -87,10 +102,13 @@ test_expect_success 'setup bare repo' \
cd bare &&
git config core.graph true &&
git config pack.threads 1 &&
- baredir="objects/pack"'
+ baredir="./objects/pack"'
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=${graphbare} >output &&
+ _graph_read_expect "18" "${baredir}" &&
+ cmp expect output'
test_done
--
2.16.0.15.g9c3cf44.dirty
