oidset: add iterator methods to oidset

Add the usual iterator methods to oidset.
Add oidset_remove().

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Reviewed-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

oidset.c

@@ -24,6 +24,16 @@ int oidset_insert(struct oidset *set, const struct object_id *oid)
 	return 0;
 }
 
+int oidset_remove(struct oidset *set, const struct object_id *oid)
+{
+	struct oidmap_entry *entry;
+
+	entry = oidmap_remove(&set->map, oid);
+	free(entry);
+
+	return (entry != NULL);
+}
+
 void oidset_clear(struct oidset *set)
 {
 	oidmap_free(&set->map, 1);

oidset.h

@@ -24,6 +24,12 @@ struct oidset {
 
 #define OIDSET_INIT { OIDMAP_INIT }
 
+
+static inline void oidset_init(struct oidset *set, size_t initial_size)
+{
+	return oidmap_init(&set->map, initial_size);
+}
+
 /**
  * Returns true iff `set` contains `oid`.
  */
@@ -38,10 +44,40 @@ int oidset_contains(const struct oidset *set, const struct object_id *oid);
  */
 int oidset_insert(struct oidset *set, const struct object_id *oid);
 
+/**
+ * Remove the oid from the set.
+ *
+ * Returns 1 if the oid was present in the set, 0 otherwise.
+ */
+int oidset_remove(struct oidset *set, const struct object_id *oid);
+
 /**
  * Remove all entries from the oidset, freeing any resources associated with
  * it.
  */
 void oidset_clear(struct oidset *set);
 
+struct oidset_iter {
+	struct oidmap_iter m_iter;
+};
+
+static inline void oidset_iter_init(struct oidset *set,
+				    struct oidset_iter *iter)
+{
+	oidmap_iter_init(&set->map, &iter->m_iter);
+}
+
+static inline struct object_id *oidset_iter_next(struct oidset_iter *iter)
+{
+	struct oidmap_entry *e = oidmap_iter_next(&iter->m_iter);
+	return e ? &e->oid : NULL;
+}
+
+static inline struct object_id *oidset_iter_first(struct oidset *set,
+						  struct oidset_iter *iter)
+{
+	oidset_iter_init(set, iter);
+	return oidset_iter_next(iter);
+}
+
 #endif /* OIDSET_H */