On 4/11/2018 4:58 PM, Jakub Narebski wrote:
Derrick Stolee <stolee@xxxxxxxxx> writes:
+CHUNK DATA:
+
+ OID Fanout (ID: {'O', 'I', 'D', 'F'}) (256 * 4 bytes)
+ The ith entry, F[i], stores the number of OIDs with first
+ byte at most i. Thus F[255] stores the total
+ number of commits (N).
+
+ OID Lookup (ID: {'O', 'I', 'D', 'L'}) (N * H bytes)
+ The OIDs for all commits in the graph, sorted in ascending order.
+
+ Commit Data (ID: {'C', 'G', 'E', 'T' }) (N * (H + 16) bytes)
I think it is a typo, and it should be CDAT, not CGET
(CDAT seem to me to stand for Commit DATa):
+ Commit Data (ID: {'C', 'D', 'A', 'T' }) (N * (H + 16) bytes)
This is what you use in actual implementation, in PATCH v8 06/14
DS> +#define GRAPH_SIGNATURE 0x43475048 /* "CGPH" */
DS> +#define GRAPH_CHUNKID_OIDFANOUT 0x4f494446 /* "OIDF" */
DS> +#define GRAPH_CHUNKID_OIDLOOKUP 0x4f49444c /* "OIDL" */
DS> +#define GRAPH_CHUNKID_DATA 0x43444154 /* "CDAT" */
DS> +#define GRAPH_CHUNKID_LARGEEDGES 0x45444745 /* "EDGE" */
Documentation bugs are hard to diagnose. Thanks for finding this. I
double checked that the hex int "0x43444154" matches "CDAT".
Here is a diff to make it match.
diff --git a/Documentation/technical/commit-graph-format.txt
b/Documentation/technical/commit-graph-format.txt
index ad6af8105c..af03501834 100644
--- a/Documentation/technical/commit-graph-format.txt
+++ b/Documentation/technical/commit-graph-format.txt
@@ -70,7 +70,7 @@ CHUNK DATA:
OID Lookup (ID: {'O', 'I', 'D', 'L'}) (N * H bytes)
The OIDs for all commits in the graph, sorted in ascending order.
- Commit Data (ID: {'C', 'G', 'E', 'T' }) (N * (H + 16) bytes)
+ Commit Data (ID: {'C', 'D', 'A', 'T' }) (N * (H + 16) bytes)
* The first H bytes are for the OID of the root tree.
* The next 8 bytes are for the positions of the first two parents
of the ith commit. Stores value 0xffffffff if no parent in that
