90 lines
2.2 KiB
Erlang
90 lines
2.2 KiB
Erlang
%%--------------------------------------------------------------------
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%% Copyright (c) 2018-2024 EMQ Technologies Co., Ltd. All Rights Reserved.
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%%
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%% Licensed under the Apache License, Version 2.0 (the "License");
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%% you may not use this file except in compliance with the License.
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%% You may obtain a copy of the License at
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%%
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%% http://www.apache.org/licenses/LICENSE-2.0
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%%
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%% Unless required by applicable law or agreed to in writing, software
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%% distributed under the License is distributed on an "AS IS" BASIS,
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%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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%% See the License for the specific language governing permissions and
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%% limitations under the License.
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%%--------------------------------------------------------------------
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-module(emqx_utils_ets).
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-export([
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new/1,
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new/2
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]).
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-export([
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lookup_value/2,
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lookup_value/3
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]).
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-export([keyfoldl/3]).
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-export([delete/1]).
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%% Create an ets table.
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-spec new(atom()) -> ok.
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new(Tab) ->
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new(Tab, []).
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%% Create a named_table ets.
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-spec new(atom(), list()) -> ok.
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new(Tab, Opts) ->
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case ets:info(Tab, name) of
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undefined ->
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_ = ets:new(Tab, lists:usort([named_table | Opts])),
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ok;
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Tab ->
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ok
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end.
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%% KV lookup
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-spec lookup_value(ets:tab(), term()) -> any().
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lookup_value(Tab, Key) ->
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lookup_value(Tab, Key, undefined).
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-spec lookup_value(ets:tab(), term(), any()) -> any().
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lookup_value(Tab, Key, Def) ->
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try
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ets:lookup_element(Tab, Key, 2)
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catch
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error:badarg -> Def
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end.
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-spec keyfoldl(fun((_Key :: term(), Acc) -> Acc), Acc, ets:tab()) -> Acc.
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keyfoldl(F, Acc, Tab) ->
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true = ets:safe_fixtable(Tab, true),
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First = ets:first(Tab),
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try
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keyfoldl(F, Acc, First, Tab)
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after
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ets:safe_fixtable(Tab, false)
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end.
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keyfoldl(F, Acc, Key, Tab) ->
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case Key of
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'$end_of_table' ->
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Acc;
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_ ->
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keyfoldl(F, F(Key, Acc), ets:next(Tab, Key), Tab)
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end.
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%% Delete the ets table.
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-spec delete(ets:tab()) -> ok.
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delete(Tab) ->
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case ets:info(Tab, name) of
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undefined ->
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ok;
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Tab ->
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ets:delete(Tab),
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ok
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end.
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