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 | 12 ++++
builtin/commit-graph.c | 56 +++++++++++++++
commit-graph.c | 140 ++++++++++++++++++++++++++++++++++++-
commit-graph.h | 23 ++++++
t/t5318-commit-graph.sh | 32 +++++++--
5 files changed, 257 insertions(+), 6 deletions(-)
diff --git a/Documentation/git-commit-graph.txt
b/Documentation/git-commit-graph.txt
index e688843..51cb038 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 graph files
SYNOPSIS
--------
[verse]
+'git commit-graph read' <options> [--object-dir <dir>]
'git commit-graph write' <options> [--object-dir <dir>]
@@ -33,6 +34,11 @@ COMMANDS
Write a commit graph file based on the commits found in packfiles.
Includes all commits from the existing commit graph file.
+'read'::
+
+Read a graph file given by the commit-graph file and output basic
+details about the graph file. Used for debugging purposes.
+
EXAMPLES
--------
@@ -43,6 +49,12 @@ EXAMPLES
$ git commit-graph write
------------------------------------------------
+* Read basic information from the commit-graph file.
++
+------------------------------------------------
+$ git commit-graph read
+------------------------------------------------
+
GIT
---
diff --git a/builtin/commit-graph.c b/builtin/commit-graph.c
index a9d61f6..0e164be 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>]"),
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>]"),
+ NULL
+};
+
static const char * const builtin_commit_graph_write_usage[] = {
N_("git commit-graph write [--object-dir <objdir>]"),
NULL
@@ -20,6 +26,54 @@ static struct opts_commit_graph {
const char *obj_dir;
} opts;
+static int graph_read(int argc, const char **argv)
+{
+ struct commit_graph *graph = 0;
+ char *graph_name;
+
+ static struct option builtin_commit_graph_read_options[] = {
+ OPT_STRING(0, "object-dir", &opts.obj_dir,
+ N_("dir"),
+ N_("The object directory to store the graph")),
+ 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();
+
+ graph_name = get_commit_graph_filename(opts.obj_dir);
+ graph = load_commit_graph_one(graph_name);
+
+ if (!graph)
+ die("graph file %s does not exist", graph_name);
+ FREE_AND_NULL(graph_name);
+
+ 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)
{
static struct option builtin_commit_graph_write_options[] = {
@@ -60,6 +114,8 @@ 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 2251397..7b0cfb4 100644
--- a/commit-graph.c
+++ b/commit-graph.c
@@ -39,11 +39,149 @@
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 = 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 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 = ntohl(*(uint32_t*)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_offset1 = get_be32(chunk_lookup + 4);
+ uint32_t chunk_offset2 = get_be32(chunk_lookup + 8);
+ uint64_t chunk_offset = (chunk_offset1 << 32) | chunk_offset2;
+ 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)
diff --git a/commit-graph.h b/commit-graph.h
index 4cb3f12..8b4b0f9 100644
--- a/commit-graph.h
+++ b/commit-graph.h
@@ -1,6 +1,29 @@
#ifndef COMMIT_GRAPH_H
#define COMMIT_GRAPH_H
+#include "git-compat-util.h"
+
+char *get_commit_graph_filename(const char *obj_dir);
+
+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;
+};
+
+struct commit_graph *load_commit_graph_one(const char *graph_file);
+
void write_commit_graph(const char *obj_dir);
#endif
diff --git a/t/t5318-commit-graph.sh b/t/t5318-commit-graph.sh
index 7524d2a..0085e23 100755
--- a/t/t5318-commit-graph.sh
+++ b/t/t5318-commit-graph.sh
@@ -26,10 +26,28 @@ test_expect_success 'create commits and repack' '
git repack
'
+graph_read_expect() {
+ OPTIONAL=""
+ NUM_CHUNKS=3
+ if test ! -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
+ git commit-graph read >output &&
+ test_cmp expect output
+}
+
test_expect_success 'write graph' '
cd "$TRASH_DIRECTORY/full" &&
graph1=$(git commit-graph write) &&
- test_path_is_file $objdir/info/commit-graph
+ test_path_is_file $objdir/info/commit-graph &&
+ graph_read_expect "3"
'
test_expect_success 'Add more commits' '
@@ -72,7 +90,8 @@ test_expect_success 'Add more commits' '
test_expect_success 'write graph with merges' '
cd "$TRASH_DIRECTORY/full" &&
git commit-graph write &&
- test_path_is_file $objdir/info/commit-graph
+ test_path_is_file $objdir/info/commit-graph &&
+ graph_read_expect "10" "large_edges"
'
test_expect_success 'Add one more commit' '
@@ -99,13 +118,15 @@ test_expect_success 'Add one more commit' '
test_expect_success 'write graph with new commit' '
cd "$TRASH_DIRECTORY/full" &&
git commit-graph write &&
- test_path_is_file $objdir/info/commit-graph
+ test_path_is_file $objdir/info/commit-graph &&
+ graph_read_expect "11" "large_edges"
'
test_expect_success 'write graph with nothing new' '
cd "$TRASH_DIRECTORY/full" &&
git commit-graph write &&
- test_path_is_file $objdir/info/commit-graph
+ test_path_is_file $objdir/info/commit-graph &&
+ graph_read_expect "11" "large_edges"
'
test_expect_success 'setup bare repo' '
@@ -118,7 +139,8 @@ test_expect_success 'setup bare repo' '
test_expect_success 'write graph in bare repo' '
cd "$TRASH_DIRECTORY/bare" &&
git commit-graph write &&
- test_path_is_file $baredir/info/commit-graph
+ test_path_is_file $baredir/info/commit-graph &&
+ graph_read_expect "11" "large_edges"
'
test_done
--
2.7.4
