merge trie records from emqttd_trie.erl to this header file

include/emqttd_trie.hrl

@@ -0,0 +1,35 @@
+%%--------------------------------------------------------------------
+%% Copyright (c) 2016 Feng Lee <feng@emqtt.io>.
+%%
+%% Licensed under the Apache License, Version 2.0 (the "License");
+%% you may not use this file except in compliance with the License.
+%% You may obtain a copy of the License at
+%%
+%%     http://www.apache.org/licenses/LICENSE-2.0
+%%
+%% Unless required by applicable law or agreed to in writing, software
+%% distributed under the License is distributed on an "AS IS" BASIS,
+%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+%% See the License for the specific language governing permissions and
+%% limitations under the License.
+%%--------------------------------------------------------------------
+
+-type trie_node_id() :: binary() | atom().
+
+-record(trie_node, {
+    node_id         :: trie_node_id(),
+    edge_count = 0  :: non_neg_integer(),
+    topic           :: binary() | undefined,
+    flags           :: [retained | static]
+}).
+
+-record(trie_edge, {
+    node_id        :: trie_node_id(),
+    word           :: binary() | atom()
+}).
+
+-record(trie, {
+    edge          :: #trie_edge{},
+    node_id       :: trie_node_id()
+}).
+