Notes API: init_notes(): Initialize the notes tree from the given notes ref

Created by a simple refactoring of initialize_notes().

Also add a new 'flags' parameter, which is a bitwise combination of notes
initialization flags. For now, there is only one flag - NOTES_INIT_EMPTY -
which indicates that the notes tree should not auto-load the contents of
the given (or default) notes ref, but rather should leave the notes tree
initialized to an empty state. This will become useful in the future when
manipulating the notes tree through the notes API.

Signed-off-by: Johan Herland <johan@herland.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 18 insertions, 12 deletions

diff --git a/notes.c b/notes.c
index 4ee4fec233..3f4ae35340 100644
--- a/notes.c
+++ b/notes.c
@@ -340,15 +340,28 @@ static void load_subtree(struct leaf_node *subtree, struct int_node *node,
 	free(buf);
 }
 
-static void initialize_notes(const char *notes_ref_name)
+void init_notes(const char *notes_ref, int flags)
 {
 	unsigned char sha1[20], object_sha1[20];
 	unsigned mode;
 	struct leaf_node root_tree;
 
-	if (!notes_ref_name || read_ref(notes_ref_name, object_sha1) ||
-	    get_tree_entry(object_sha1, "", sha1, &mode))
+	assert(!initialized);
+	initialized = 1;
+
+	if (!notes_ref)
+		notes_ref = getenv(GIT_NOTES_REF_ENVIRONMENT);
+	if (!notes_ref)
+		notes_ref = notes_ref_name; /* value of core.notesRef config */
+	if (!notes_ref)
+		notes_ref = GIT_NOTES_DEFAULT_REF;
+
+	if (flags & NOTES_INIT_EMPTY || !notes_ref ||
+	    read_ref(notes_ref, object_sha1))
 		return;
+	if (get_tree_entry(object_sha1, "", sha1, &mode))
+		die("Failed to read notes tree referenced by %s (%s)",
+		    notes_ref, object_sha1);
 
 	hashclr(root_tree.key_sha1);
 	hashcpy(root_tree.val_sha1, sha1);
@@ -379,15 +392,8 @@ void format_note(const unsigned char *object_sha1, struct strbuf *sb,
 	unsigned long linelen, msglen;
 	enum object_type type;
 
-	if (!initialized) {
-		const char *env = getenv(GIT_NOTES_REF_ENVIRONMENT);
-		if (env)
-			notes_ref_name = getenv(GIT_NOTES_REF_ENVIRONMENT);
-		else if (!notes_ref_name)
-			notes_ref_name = GIT_NOTES_DEFAULT_REF;
-		initialize_notes(notes_ref_name);
-		initialized = 1;
-	}
+	if (!initialized)
+		init_notes(NULL, 0);
 
 	sha1 = lookup_notes(object_sha1);
 	if (!sha1)