odb: Move the auto refresh logic to the pack backend

Previously, `git_object_read()`, `git_object_read_prefix()` and
`git_object_exists()` were implementing an auto refresh logic. When the
expected object couldn't be found in any backend, a call to
`git_odb_refresh()` was triggered and the lookup was once again performed
against all backends.

This commit removes this auto-refresh logic from the odb layer and pushes
it down into the pack-backend (as it's the only one currently exposing
a `refresh()` endpoint).

1 files changed, 73 insertions, 3 deletions

diff --git a/src/odb_pack.c b/src/odb_pack.c
index d7abd1020..d24b4aa99 100644
--- a/src/odb_pack.c
+++ b/src/odb_pack.c
@@ -342,7 +342,7 @@ static int pack_backend__refresh(git_odb_backend *_backend)
 	return 0;
 }
 
-static int pack_backend__read_header(
+static int pack_backend__read_header_internal(
 	size_t *len_p, git_otype *type_p,
 	struct git_odb_backend *backend, const git_oid *oid)
 {
@@ -357,7 +357,24 @@ static int pack_backend__read_header(
 	return git_packfile_resolve_header(len_p, type_p, e.p, e.offset);
 }
 
-static int pack_backend__read(
+static int pack_backend__read_header(
+	size_t *len_p, git_otype *type_p,
+	struct git_odb_backend *backend, const git_oid *oid)
+{
+	int error;
+
+	error = pack_backend__read_header_internal(len_p, type_p, backend, oid);
+
+	if (error != GIT_ENOTFOUND)
+		return error;
+
+	if ((error = pack_backend__refresh(backend)) < 0)
+		return error;
+
+	return pack_backend__read_header_internal(len_p, type_p, backend, oid);
+}
+
+static int pack_backend__read_internal(
 	void **buffer_p, size_t *len_p, git_otype *type_p,
 	git_odb_backend *backend, const git_oid *oid)
 {
@@ -376,7 +393,24 @@ static int pack_backend__read(
 	return 0;
 }
 
-static int pack_backend__read_prefix(
+static int pack_backend__read(
+	void **buffer_p, size_t *len_p, git_otype *type_p,
+	git_odb_backend *backend, const git_oid *oid)
+{
+	int error;
+
+	error = pack_backend__read_internal(buffer_p, len_p, type_p, backend, oid);
+
+	if (error != GIT_ENOTFOUND)
+		return error;
+
+	if ((error = pack_backend__refresh(backend)) < 0)
+		return error;
+
+	return pack_backend__read_internal(buffer_p, len_p, type_p, backend, oid);
+}
+
+static int pack_backend__read_prefix_internal(
 	git_oid *out_oid,
 	void **buffer_p,
 	size_t *len_p,
@@ -413,9 +447,45 @@ static int pack_backend__read_prefix(
 	return error;
 }
 
+static int pack_backend__read_prefix(
+	git_oid *out_oid,
+	void **buffer_p,
+	size_t *len_p,
+	git_otype *type_p,
+	git_odb_backend *backend,
+	const git_oid *short_oid,
+	size_t len)
+{
+	int error;
+
+	error = pack_backend__read_prefix_internal(
+		out_oid, buffer_p, len_p, type_p, backend, short_oid, len);
+
+	if (error != GIT_ENOTFOUND)
+		return error;
+
+	if ((error = pack_backend__refresh(backend)) < 0)
+		return error;
+
+	return pack_backend__read_prefix_internal(
+		out_oid, buffer_p, len_p, type_p, backend, short_oid, len);
+}
+
 static int pack_backend__exists(git_odb_backend *backend, const git_oid *oid)
 {
 	struct git_pack_entry e;
+	int error;
+
+	error = pack_entry_find(&e, (struct pack_backend *)backend, oid);
+
+	if (error != GIT_ENOTFOUND)
+		return error == 0;
+
+	if ((error = pack_backend__refresh(backend)) < 0) {
+		giterr_clear();
+		return (int)false;
+	}
+
 	return pack_entry_find(&e, (struct pack_backend *)backend, oid) == 0;
 }