merge(third_party/git): Merge squashed git subtree at v2.23.0

Merge commit '1b593e1ea4' as 'third_party/git'

third_party/git/notes-cache.c

@@ -0,0 +1,98 @@
+#include "cache.h"
+#include "notes-cache.h"
+#include "object-store.h"
+#include "repository.h"
+#include "commit.h"
+#include "refs.h"
+
+static int notes_cache_match_validity(struct repository *r,
+				      const char *ref,
+				      const char *validity)
+{
+	struct object_id oid;
+	struct commit *commit;
+	struct pretty_print_context pretty_ctx;
+	struct strbuf msg = STRBUF_INIT;
+	int ret;
+
+	if (read_ref(ref, &oid) < 0)
+		return 0;
+
+	commit = lookup_commit_reference_gently(r, &oid, 1);
+	if (!commit)
+		return 0;
+
+	memset(&pretty_ctx, 0, sizeof(pretty_ctx));
+	format_commit_message(commit, "%s", &msg, &pretty_ctx);
+	strbuf_trim(&msg);
+
+	ret = !strcmp(msg.buf, validity);
+	strbuf_release(&msg);
+
+	return ret;
+}
+
+void notes_cache_init(struct repository *r, struct notes_cache *c,
+		      const char *name, const char *validity)
+{
+	struct strbuf ref = STRBUF_INIT;
+	int flags = NOTES_INIT_WRITABLE;
+
+	memset(c, 0, sizeof(*c));
+	c->validity = xstrdup(validity);
+
+	strbuf_addf(&ref, "refs/notes/%s", name);
+	if (!notes_cache_match_validity(r, ref.buf, validity))
+		flags |= NOTES_INIT_EMPTY;
+	init_notes(&c->tree, ref.buf, combine_notes_overwrite, flags);
+	strbuf_release(&ref);
+}
+
+int notes_cache_write(struct notes_cache *c)
+{
+	struct object_id tree_oid, commit_oid;
+
+	if (!c || !c->tree.initialized || !c->tree.update_ref ||
+	    !*c->tree.update_ref)
+		return -1;
+	if (!c->tree.dirty)
+		return 0;
+
+	if (write_notes_tree(&c->tree, &tree_oid))
+		return -1;
+	if (commit_tree(c->validity, strlen(c->validity), &tree_oid, NULL,
+			&commit_oid, NULL, NULL) < 0)
+		return -1;
+	if (update_ref("update notes cache", c->tree.update_ref, &commit_oid,
+		       NULL, 0, UPDATE_REFS_QUIET_ON_ERR) < 0)
+		return -1;
+
+	return 0;
+}
+
+char *notes_cache_get(struct notes_cache *c, struct object_id *key_oid,
+		      size_t *outsize)
+{
+	const struct object_id *value_oid;
+	enum object_type type;
+	char *value;
+	unsigned long size;
+
+	value_oid = get_note(&c->tree, key_oid);
+	if (!value_oid)
+		return NULL;
+	value = read_object_file(value_oid, &type, &size);
+
+	*outsize = size;
+	return value;
+}
+
+int notes_cache_put(struct notes_cache *c, struct object_id *key_oid,
+		    const char *data, size_t size)
+{
+	struct object_id value_oid;
+
+	if (write_object_file(data, size, "blob", &value_oid) < 0)
+		return -1;
+	return add_note(&c->tree, key_oid, &value_oid, NULL);
+}