From 56718e35cb9f7fbba996c87ca1a5fd850b2083d1 Mon Sep 17 00:00:00 2001
From: Feng Lee <feng@emqtt.io>
Date: Wed, 13 Mar 2019 23:31:44 +0800
Subject: [PATCH] Add emqx_topic:tokens/1 function (#2305)

* Add emqx_topic:tokens/1 function
---
 src/emqx_topic.erl        | 15 +++++++++++----
 test/emqx_topic_SUITE.erl | 27 ++++++++++++++++++++++-----
 2 files changed, 33 insertions(+), 9 deletions(-)

diff --git a/src/emqx_topic.erl b/src/emqx_topic.erl
index bb615ccfe..0b18fdf23 100644
--- a/src/emqx_topic.erl
+++ b/src/emqx_topic.erl
@@ -14,10 +14,13 @@
 
 -module(emqx_topic).
 
+-include("emqx_mqtt.hrl").
+
 -export([match/2]).
 -export([validate/1, validate/2]).
 -export([levels/1]).
 -export([triples/1]).
+-export([tokens/1]).
 -export([words/1]).
 -export([wildcard/1]).
 -export([join/1, prepend/2]).
@@ -35,8 +38,6 @@
 
 -define(MAX_TOPIC_LEN, 4096).
 
--include("emqx_mqtt.hrl").
-
 %% @doc Is wildcard topic?
 -spec(wildcard(topic() | words()) -> true | false).
 wildcard(Topic) when is_binary(Topic) ->
@@ -147,13 +148,19 @@ bin('#') -> <<"#">>;
 bin(B) when is_binary(B) -> B;
 bin(L) when is_list(L) -> list_to_binary(L).
 
+-spec(levels(topic()) -> pos_integer()).
 levels(Topic) when is_binary(Topic) ->
-    length(words(Topic)).
+    length(tokens(Topic)).
+
+%% @doc Split topic to tokens.
+-spec(tokens(topic()) -> list(binary())).
+tokens(Topic) ->
+    binary:split(Topic, <<"/">>, [global]).
 
 %% @doc Split Topic Path to Words
 -spec(words(topic()) -> words()).
 words(Topic) when is_binary(Topic) ->
-    [word(W) || W <- binary:split(Topic, <<"/">>, [global])].
+    [word(W) || W <- tokens(Topic)].
 
 word(<<>>)    -> '';
 word(<<"+">>) -> '+';
diff --git a/test/emqx_topic_SUITE.erl b/test/emqx_topic_SUITE.erl
index 2ad57154d..0a51598ee 100644
--- a/test/emqx_topic_SUITE.erl
+++ b/test/emqx_topic_SUITE.erl
@@ -20,8 +20,17 @@
 -compile(export_all).
 -compile(nowarn_export_all).
 
--import(emqx_topic, [wildcard/1, match/2, validate/1, triples/1, join/1,
-                     words/1, systop/1, feed_var/3, parse/1]).
+-import(emqx_topic,
+        [wildcard/1,
+         match/2,
+         validate/1,
+         triples/1,
+         join/1,
+         words/1,
+         systop/1,
+         feed_var/3,
+         parse/1
+        ]).
 
 -define(N, 10000).
 
@@ -32,6 +41,7 @@ all() ->
      t_triples,
      t_join,
      t_levels,
+     t_tokens,
      t_words,
      t_systop,
      t_feed_var,
@@ -165,6 +175,9 @@ t_triples_perf(_) ->
 t_levels(_) ->
     ?assertEqual(4, emqx_topic:levels(<<"a/b/c/d">>)).
 
+t_tokens(_) ->
+    ?assertEqual([<<"a">>, <<"b">>, <<"+">>, <<"#">>], emqx_topic:tokens(<<"a/b/+/#">>)).
+
 t_words(_) ->
     ['', <<"a">>, '+', '#'] = words(<<"/a/+/#">>),
     ['', <<"abkc">>, <<"19383">>, '+', <<"akakdkkdkak">>, '#'] = words(<<"/abkc/19383/+/akakdkkdkak/#">>),
@@ -193,9 +206,12 @@ t_systop(_) ->
     ?assertEqual(SysTop2,systop(<<"abc">>)).
 
 t_feed_var(_) ->
-    ?assertEqual(<<"$queue/client/clientId">>, feed_var(<<"$c">>, <<"clientId">>, <<"$queue/client/$c">>)),
-    ?assertEqual(<<"username/test/client/x">>, feed_var(<<"%u">>, <<"test">>, <<"username/%u/client/x">>)),
-    ?assertEqual(<<"username/test/client/clientId">>, feed_var(<<"%c">>, <<"clientId">>, <<"username/test/client/%c">>)).
+    ?assertEqual(<<"$queue/client/clientId">>,
+                 feed_var(<<"$c">>, <<"clientId">>, <<"$queue/client/$c">>)),
+    ?assertEqual(<<"username/test/client/x">>,
+                 feed_var(<<"%u">>, <<"test">>, <<"username/%u/client/x">>)),
+    ?assertEqual(<<"username/test/client/clientId">>,
+                 feed_var(<<"%c">>, <<"clientId">>, <<"username/test/client/%c">>)).
 
 long_topic() ->
     iolist_to_binary([[integer_to_list(I), "/"] || I <- lists:seq(0, 10000)]).
@@ -208,3 +224,4 @@ t_parse(_) ->
     ?assertEqual({<<"$local/$queue/topic">>, #{}}, parse(<<"$local/$queue/topic">>)),
     ?assertEqual({<<"$local/$share/group/a/b/c">>, #{}}, parse(<<"$local/$share/group/a/b/c">>)),
     ?assertEqual({<<"$fastlane/topic">>, #{}}, parse(<<"$fastlane/topic">>)).
+