oid: introduce git_oid_raw

We make frequent use of an oid structure that assumes that it's simply
20 bytes of raw data.  This will certainly not always be the case.

Provide a raw type that is 20 bytes of raw data, so that our public-
facing `git_oid` type can be more flexible and possibly learn a type
annotation that indicates its size.

2 files changed, 15 insertions, 1 deletions

diff --git a/src/oid.h b/src/oid.h
index 84231ffca..e1a29ed53 100644
--- a/src/oid.h
+++ b/src/oid.h
@@ -12,6 +12,16 @@
 #include "git2/oid.h"
 
 /**
+ * A "raw" object ID without any additional metadata like the type.
+ *
+ * This is useful for internal-facing data structures like commit
+ * graphs and indexes.
+ */
+typedef struct git_oid_raw {
+	unsigned char id[GIT_OID_RAWSZ];
+} git_oid_raw;
+
+/**
  * Format a git_oid into a newly allocated c-string.
  *
  * The c-string is owned by the caller and needs to be manually freed.
diff --git a/tests/object/raw/size.c b/tests/object/raw/size.c
index 930c6de23..df25ab427 100644
--- a/tests/object/raw/size.c
+++ b/tests/object/raw/size.c
@@ -2,12 +2,16 @@
 #include "clar_libgit2.h"
 
 #include "odb.h"
+#include "oid.h"
 
 void test_object_raw_size__validate_oid_size(void)
 {
 	git_oid out;
+	git_oid_raw raw;
+
 	cl_assert(20 == GIT_OID_RAWSZ);
 	cl_assert(40 == GIT_OID_HEXSZ);
-	cl_assert(sizeof(out) == GIT_OID_RAWSZ);
 	cl_assert(sizeof(out.id) == GIT_OID_RAWSZ);
+	cl_assert(sizeof(raw) == GIT_OID_RAWSZ);
+	cl_assert(sizeof(raw.id) == GIT_OID_RAWSZ);
 }