Derrick Stolee <dsto...@microsoft.com> writes:
> Most code paths load commits using lookup_commit() and then
> parse_commit(). In some cases, including some branch lookups, the commit
> is parsed using parse_object_buffer() which side-steps parse_commit() in
> favor of parse_commit_buffer().
>
> With generation numbers in the commit-graph, we need to ensure that any
> commit that exists in the commit-graph file has its generation number
> loaded.
All right, that is nice explanation of the why behind this change.
>
> Create new load_commit_graph_info() method to fill in the information
> for a commit that exists only in the commit-graph file. Call it from
> parse_commit_buffer() after loading the other commit information from
> the given buffer. Only fill this information when specified by the
> 'check_graph' parameter. This avoids duplicate work when we already
> checked the graph in parse_commit_gently() or when simply checking the
> buffer contents in check_commit().
Couldn't this 'check_graph' parameter be a global variable similar to
the 'commit_graph' variable? Maybe I am not understanding it.
>
> Signed-off-by: Derrick Stolee <dsto...@microsoft.com>
> ---
> commit-graph.c | 51 ++++++++++++++++++++++++++++++++------------------
> commit-graph.h | 8 ++++++++
> commit.c | 7 +++++--
> commit.h | 2 +-
> object.c | 2 +-
> sha1_file.c | 2 +-
> 6 files changed, 49 insertions(+), 23 deletions(-)
>
> diff --git a/commit-graph.c b/commit-graph.c
> index 688d5b1801..21e853c21a 100644
> --- a/commit-graph.c
> +++ b/commit-graph.c
> @@ -245,13 +245,19 @@ static struct commit_list **insert_parent_or_die(struct
> commit_graph *g,
> return &commit_list_insert(c, pptr)->next;
> }
>
> +static void fill_commit_graph_info(struct commit *item, struct commit_graph
> *g, uint32_t pos)
> +{
> + const unsigned char *commit_data = g->chunk_commit_data +
> GRAPH_DATA_WIDTH * pos;
> + item->generation = get_be32(commit_data + g->hash_len + 8) >> 2;
> +}
> +
> static int fill_commit_in_graph(struct commit *item, struct commit_graph *g,
> uint32_t pos)
> {
> uint32_t edge_value;
> uint32_t *parent_data_ptr;
> uint64_t date_low, date_high;
> struct commit_list **pptr;
> - const unsigned char *commit_data = g->chunk_commit_data + (g->hash_len
> + 16) * pos;
> + const unsigned char *commit_data = g->chunk_commit_data +
> GRAPH_DATA_WIDTH * pos;
I'm probably wrong, but isn't it unrelated change?
>
> item->object.parsed = 1;
> item->graph_pos = pos;
> @@ -292,31 +298,40 @@ static int fill_commit_in_graph(struct commit *item,
> struct commit_graph *g, uin
> return 1;
> }
>
> +static int find_commit_in_graph(struct commit *item, struct commit_graph *g,
> uint32_t *pos)
> +{
> + if (item->graph_pos != COMMIT_NOT_FROM_GRAPH) {
> + *pos = item->graph_pos;
> + return 1;
> + } else {
> + return bsearch_graph(commit_graph, &(item->object.oid), pos);
> + }
> +}
All right (after the fix).
> +
> int parse_commit_in_graph(struct commit *item)
> {
> + uint32_t pos;
> +
> + if (item->object.parsed)
> + return 0;
> if (!core_commit_graph)
> return 0;
> - if (item->object.parsed)
> - return 1;
Hmmm... previously the function returned 1 if item->object.parsed, now
it returns 0 for this situation. I don't understand this change.
> -
> prepare_commit_graph();
> - if (commit_graph) {
> - uint32_t pos;
> - int found;
> - if (item->graph_pos != COMMIT_NOT_FROM_GRAPH) {
> - pos = item->graph_pos;
> - found = 1;
> - } else {
> - found = bsearch_graph(commit_graph,
> &(item->object.oid), &pos);
> - }
> -
> - if (found)
> - return fill_commit_in_graph(item, commit_graph, pos);
> - }
> -
> + if (commit_graph && find_commit_in_graph(item, commit_graph, &pos))
> + return fill_commit_in_graph(item, commit_graph, pos);
Nice refactoring.
> return 0;
> }
>
> +void load_commit_graph_info(struct commit *item)
> +{
> + uint32_t pos;
> + if (!core_commit_graph)
> + return;
> + prepare_commit_graph();
> + if (commit_graph && find_commit_in_graph(item, commit_graph, &pos))
> + fill_commit_graph_info(item, commit_graph, pos);
> +}
And the reason for the refactoring.
> +
> static struct tree *load_tree_for_commit(struct commit_graph *g, struct
> commit *c)
> {
> struct object_id oid;
> diff --git a/commit-graph.h b/commit-graph.h
> index 260a468e73..96cccb10f3 100644
> --- a/commit-graph.h
> +++ b/commit-graph.h
> @@ -17,6 +17,14 @@ char *get_commit_graph_filename(const char *obj_dir);
> */
> int parse_commit_in_graph(struct commit *item);
>
> +/*
> + * It is possible that we loaded commit contents from the commit buffer,
> + * but we also want to ensure the commit-graph content is correctly
> + * checked and filled. Fill the graph_pos and generation members of
> + * the given commit.
> + */
> +void load_commit_graph_info(struct commit *item);
> +
> struct tree *get_commit_tree_in_graph(const struct commit *c);
>
> struct commit_graph {
> diff --git a/commit.c b/commit.c
> index a70f120878..9ef6f699bd 100644
> --- a/commit.c
> +++ b/commit.c
> @@ -331,7 +331,7 @@ const void *detach_commit_buffer(struct commit *commit,
> unsigned long *sizep)
> return ret;
> }
>
> -int parse_commit_buffer(struct commit *item, const void *buffer, unsigned
> long size)
> +int parse_commit_buffer(struct commit *item, const void *buffer, unsigned
> long size, int check_graph)
> {
> const char *tail = buffer;
> const char *bufptr = buffer;
> @@ -386,6 +386,9 @@ int parse_commit_buffer(struct commit *item, const void
> *buffer, unsigned long s
> }
> item->date = parse_commit_date(bufptr, tail);
>
> + if (check_graph)
> + load_commit_graph_info(item);
> +
> return 0;
> }
>
> @@ -412,7 +415,7 @@ int parse_commit_gently(struct commit *item, int
> quiet_on_missing)
> return error("Object %s not a commit",
> oid_to_hex(&item->object.oid));
> }
> - ret = parse_commit_buffer(item, buffer, size);
> + ret = parse_commit_buffer(item, buffer, size, 0);
> if (save_commit_buffer && !ret) {
> set_commit_buffer(item, buffer, size);
> return 0;
> diff --git a/commit.h b/commit.h
> index 64436ff44e..b5afde1ae9 100644
> --- a/commit.h
> +++ b/commit.h
> @@ -72,7 +72,7 @@ struct commit *lookup_commit_reference_by_name(const char
> *name);
> */
> struct commit *lookup_commit_or_die(const struct object_id *oid, const char
> *ref_name);
>
> -int parse_commit_buffer(struct commit *item, const void *buffer, unsigned
> long size);
> +int parse_commit_buffer(struct commit *item, const void *buffer, unsigned
> long size, int check_graph);
> int parse_commit_gently(struct commit *item, int quiet_on_missing);
> static inline int parse_commit(struct commit *item)
> {
> diff --git a/object.c b/object.c
> index e6ad3f61f0..efe4871325 100644
> --- a/object.c
> +++ b/object.c
> @@ -207,7 +207,7 @@ struct object *parse_object_buffer(const struct object_id
> *oid, enum object_type
> } else if (type == OBJ_COMMIT) {
> struct commit *commit = lookup_commit(oid);
> if (commit) {
> - if (parse_commit_buffer(commit, buffer, size))
> + if (parse_commit_buffer(commit, buffer, size, 1))
> return NULL;
> if (!get_cached_commit_buffer(commit, NULL)) {
> set_commit_buffer(commit, buffer, size);
> diff --git a/sha1_file.c b/sha1_file.c
> index 1b94f39c4c..0fd4f0b8b6 100644
> --- a/sha1_file.c
> +++ b/sha1_file.c
> @@ -1755,7 +1755,7 @@ static void check_commit(const void *buf, size_t size)
> {
> struct commit c;
> memset(&c, 0, sizeof(c));
> - if (parse_commit_buffer(&c, buf, size))
> + if (parse_commit_buffer(&c, buf, size, 0))
> die("corrupt commit");
> }
