[PATCH v4 02/10] commit: add generation number to struct commmit
- From
Derrick Stolee <dstolee@microsoft.com>
- Date
- Apr 25, 2018, 14:37 UTC
- Message-ID
- <20180425143735.240183-3-dstolee@microsoft.com>
- In-Reply-To
- <20180425143735.240183-1-dstolee@microsoft.com>
The generation number of a commit is defined recursively as follows:
* If a commit A has no parents, then the generation number of A is one. * If a commit A has parents, then the generation number of A is one more than the maximum generation number among the parents of A.
Add a uint32_t generation field to struct commit so we can pass this information to revision walks. We use three special values to signal the generation number is invalid:
GENERATION_NUMBER_INFINITY 0xFFFFFFFF GENERATION_NUMBER_MAX 0x3FFFFFFF GENERATION_NUMBER_ZERO 0
The first (_INFINITY) means the generation number has not been loaded or computed. The second (_MAX) means the generation number is too large to store in the commit-graph file. The third (_ZERO) means the generation number was loaded from a commit graph file that was written by a version of git that did not support generation numbers.
Signed-off-by: Derrick Stolee <dstolee@microsoft.com> --- alloc.c | 1 + commit-graph.c | 2 ++ commit.h | 4 ++++ 3 files changed, 7 insertions(+)
diff --git a/alloc.c b/alloc.c index cf4f8b61e1..e8ab14f4a1 100644 --- a/alloc.c +++ b/alloc.c @@ -94,6 +94,7 @@ void *alloc_commit_node(void) c->object.type = OBJ_COMMIT; c->index = alloc_commit_index(); c->graph_pos = COMMIT_NOT_FROM_GRAPH; + c->generation = GENERATION_NUMBER_INFINITY; return c; } diff --git a/commit-graph.c b/commit-graph.c index 70fa1b25fd..9ad21c3ffb 100644 --- a/commit-graph.c +++ b/commit-graph.c @@ -262,6 +262,8 @@ static int fill_commit_in_graph(struct commit *item, struct commit_graph *g, uin date_low = get_be32(commit_data + g->hash_len + 12); item->date = (timestamp_t)((date_high << 32) | date_low); + item->generation = get_be32(commit_data + g->hash_len + 8) >> 2; + pptr = &item->parents; edge_value = get_be32(commit_data + g->hash_len); diff --git a/commit.h b/commit.h index 23a3f364ed..aac3b8c56f 100644 --- a/commit.h +++ b/commit.h @@ -10,6 +10,9 @@ #include "pretty.h" #define COMMIT_NOT_FROM_GRAPH 0xFFFFFFFF +#define GENERATION_NUMBER_INFINITY 0xFFFFFFFF +#define GENERATION_NUMBER_MAX 0x3FFFFFFF +#define GENERATION_NUMBER_ZERO 0 struct commit_list { struct commit *item; @@ -30,6 +33,7 @@ struct commit { */ struct tree *maybe_tree; uint32_t graph_pos; + uint32_t generation; }; extern int save_commit_buffer;
-- 2.17.0.39.g685157f7fb