Teach git-graph to read packed graph files and summarize their contents.
Use the --read option to verify the contents of a graph file in the
graph tests.
Signed-off-by: Derrick Stolee <dstolee@xxxxxxxxxxxxx>
---
Documentation/git-graph.txt | 7 +++
builtin/graph.c | 54 ++++++++++++++++
packed-graph.c | 147 +++++++++++++++++++++++++++++++++++++++++++-
packed-graph.h | 25 ++++++++
t/t5319-graph.sh | 50 +++++++++------
5 files changed, 260 insertions(+), 23 deletions(-)
diff --git a/Documentation/git-graph.txt b/Documentation/git-graph.txt
index be6bc38814..0939c3f1be 100644
--- a/Documentation/git-graph.txt
+++ b/Documentation/git-graph.txt
@@ -10,6 +10,7 @@ SYNOPSIS
--------
[verse]
'git graph' --write <options> [--pack-dir <pack_dir>]
+'git graph' --read <options> [--pack-dir <pack_dir>]
EXAMPLES
--------
@@ -20,6 +21,12 @@ EXAMPLES
$ git midx --write
------------------------------------------------
+* Read basic information from a graph file.
++
+------------------------------------------------
+$ git midx --read --graph-id=<oid>
+------------------------------------------------
+
CONFIGURATION
-------------
diff --git a/builtin/graph.c b/builtin/graph.c
index 09f5552338..bc66722924 100644
--- a/builtin/graph.c
+++ b/builtin/graph.c
@@ -10,15 +10,58 @@
static char const * const builtin_graph_usage[] ={
N_("git graph [--pack-dir <packdir>]"),
+ N_("git graph --read [--graph-id=<oid>]"),
N_("git graph --write [--pack-dir <packdir>]"),
NULL
};
static struct opts_graph {
const char *pack_dir;
+ int read;
+ const char *graph_id;
int write;
} opts;
+static int graph_read(void)
+{
+ struct object_id graph_oid;
+ struct packed_graph *graph = 0;
+ const char *graph_file;
+
+ if (opts.graph_id && strlen(opts.graph_id) == GIT_MAX_HEXSZ)
+ get_oid_hex(opts.graph_id, &graph_oid);
+ else
+ die("no graph id specified");
+
+ graph_file = get_graph_filename_oid(opts.pack_dir, &graph_oid);
+ graph = load_packed_graph_one(graph_file, opts.pack_dir);
+
+ if (!graph)
+ die("graph file %s does not exist.\n", 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_id = construct_graph(opts.pack_dir);
@@ -36,8 +79,14 @@ int cmd_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 graph file")),
+ { OPTION_STRING, 'M', "graph-id", &opts.graph_id,
+ N_("oid"),
+ N_("An OID for a specific graph file in the pack-dir."),
+ PARSE_OPT_OPTARG, NULL, (intptr_t) "" },
OPT_END(),
};
@@ -52,6 +101,9 @@ int cmd_graph(int argc, const char **argv, const char *prefix)
builtin_graph_options,
builtin_graph_usage, 0);
+ if (opts.write + opts.read > 1)
+ usage_with_options(builtin_graph_usage, builtin_graph_options);
+
if (!opts.pack_dir) {
struct strbuf path = STRBUF_INIT;
strbuf_addstr(&path, get_object_directory());
@@ -59,6 +111,8 @@ int cmd_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/packed-graph.c b/packed-graph.c
index 9be9811667..eaa656becb 100644
--- a/packed-graph.c
+++ b/packed-graph.c
@@ -30,6 +30,11 @@
#define GRAPH_LAST_EDGE 0x80000000
+#define GRAPH_FANOUT_SIZE (4*256)
+#define GRAPH_CHUNKLOOKUP_SIZE (5 * 12)
+#define GRAPH_MIN_SIZE (GRAPH_CHUNKLOOKUP_SIZE + GRAPH_FANOUT_SIZE + \
+ GRAPH_OID_LEN + sizeof(struct packed_graph_header))
+
char* get_graph_filename_oid(const char *pack_dir,
struct object_id *oid)
{
@@ -43,6 +48,142 @@ char* get_graph_filename_oid(const char *pack_dir,
return strbuf_detach(&head_path, &len);
}
+static struct packed_graph *alloc_packed_graph(int extra)
+{
+ struct packed_graph *g = xmalloc(st_add(sizeof(*g), extra));
+ memset(g, 0, sizeof(*g));
+ g->graph_fd = -1;
+
+ return g;
+}
+
+int close_graph(struct packed_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_packed_graph(struct packed_graph **g)
+{
+ if (!g || !*g)
+ return;
+
+ close_graph(*g);
+
+ free(*g);
+ *g = NULL;
+}
+
+struct packed_graph *load_packed_graph_one(const char *graph_file, const char *pack_dir)
+{
+ void *graph_map;
+ const unsigned char *data;
+ struct packed_graph_header *hdr;
+ size_t graph_size;
+ struct stat st;
+ uint32_t i;
+ struct packed_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_packed_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_packed_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)
@@ -338,8 +479,8 @@ struct object_id *construct_graph(const char *pack_dir)
chunk_ids[3] = GRAPH_CHUNKID_LARGEEDGES;
chunk_ids[4] = 0;
- chunk_offsets[0] = sizeof(hdr) + 12 * 5; // Skip header and chunk list
- chunk_offsets[1] = chunk_offsets[0] + 256 * 4; // fanout table size
+ chunk_offsets[0] = sizeof(hdr) + GRAPH_CHUNKLOOKUP_SIZE;
+ chunk_offsets[1] = chunk_offsets[0] + GRAPH_FANOUT_SIZE;
chunk_offsets[2] = chunk_offsets[1] + GRAPH_OID_LEN * commits.num; // lookup size
chunk_offsets[3] = chunk_offsets[2] + (GRAPH_OID_LEN + 16) * commits.num; // data size
chunk_offsets[4] = chunk_offsets[3] + 4 * num_long_edges;
@@ -361,7 +502,7 @@ struct object_id *construct_graph(const char *pack_dir)
sha1close(f, final_hash, CSUM_CLOSE | CSUM_FSYNC);
f_oid = (struct object_id *)malloc(sizeof(struct object_id));
- memcpy(f_oid->hash, final_hash, GIT_MAX_RAWSZ);
+ hashcpy(f_oid->hash, final_hash);
fname = get_graph_filename_oid(pack_dir, f_oid);
if (rename(graph_name, fname))
diff --git a/packed-graph.h b/packed-graph.h
index d4e10fb612..1a7eaa2a46 100644
--- a/packed-graph.h
+++ b/packed-graph.h
@@ -15,6 +15,31 @@ struct packed_graph_header {
unsigned char num_chunks;
};
+extern struct packed_graph {
+ int graph_fd;
+
+ const unsigned char *data;
+ size_t data_len;
+
+ const struct packed_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 */
+} *packed_graph;
+
+extern int close_graph(struct packed_graph *g);
+
+extern struct packed_graph *load_packed_graph_one(const char *graph_file, const char *pack_dir);
+
extern struct object_id *construct_graph(const char *pack_dir);
#endif
diff --git a/t/t5319-graph.sh b/t/t5319-graph.sh
index 52e979dfd3..4975f65dee 100755
--- a/t/t5319-graph.sh
+++ b/t/t5319-graph.sh
@@ -3,8 +3,7 @@
test_description='packed graph'
. ./test-lib.sh
-test_expect_success \
- 'setup full repo' \
+test_expect_success 'setup full repo' \
'rm -rf .git &&
mkdir full &&
cd full &&
@@ -13,12 +12,10 @@ test_expect_success \
git config pack.threads 1 &&
packdir=".git/objects/pack"'
-test_expect_success \
- 'write graph with no packs' \
+test_expect_success 'write graph with no packs' \
'git graph --write --pack-dir .'
-test_expect_success \
- 'create commits and repack' \
+test_expect_success 'create commits and repack' \
'for i in $(test_seq 5)
do
echo $i >$i.txt &&
@@ -28,13 +25,23 @@ test_expect_success \
done &&
git repack'
-test_expect_success \
- 'write graph' \
+_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 graph --write) &&
- test_path_is_file ${packdir}/graph-${graph1}.graph'
+ test_path_is_file ${packdir}/graph-${graph1}.graph &&
+ git graph --read --graph-id=${graph1} >output &&
+ _graph_read_expect "5" "${packdir}" &&
+ cmp expect output'
-test_expect_success \
- 'Add more commits' \
+test_expect_success 'Add more commits' \
'git reset --hard commits/3 &&
for i in $(test_seq 6 10)
do
@@ -61,23 +68,26 @@ test_expect_success \
git merge commits/5 commits/13 &&
git repack'
-test_expect_success \
- 'write graph with merges' \
+test_expect_success 'write graph with merges' \
'graph2=$(git graph --write) &&
- test_path_is_file ${packdir}/graph-${graph2}.graph'
+ test_path_is_file ${packdir}/graph-${graph2}.graph &&
+ git graph --read --graph-id=${graph2} >output &&
+ _graph_read_expect "18" "${packdir}" &&
+ cmp expect output'
-test_expect_success \
- 'setup bare repo' \
+test_expect_success 'setup bare repo' \
'cd .. &&
git clone --bare full bare &&
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' \
+test_expect_success 'write graph in bare repo' \
'graphbare=$(git graph --write) &&
- test_path_is_file ${baredir}/graph-${graphbare}.graph'
+ test_path_is_file ${baredir}/graph-${graphbare}.graph &&
+ git graph --read --graph-id=${graphbare} >output &&
+ _graph_read_expect "18" "${baredir}" &&
+ cmp expect output'
test_done
--
2.16.0
