109 lines
3.4 KiB
Erlang
109 lines
3.4 KiB
Erlang
%%--------------------------------------------------------------------
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%% Copyright (c) 2020-2021 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_rule_sqlparser).
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-include("rule_engine.hrl").
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-export([parse_select/1]).
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-export([ select_fields/1
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, select_is_foreach/1
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, select_doeach/1
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, select_incase/1
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, select_from/1
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, select_where/1
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]).
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-import(proplists, [ get_value/2
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, get_value/3
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]).
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-record(select, {fields, from, where, is_foreach, doeach, incase}).
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-opaque(select() :: #select{}).
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-type(const() :: {const, number()|binary()}).
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-type(variable() :: binary() | list(binary())).
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-type(alias() :: binary() | list(binary())).
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-type(field() :: const() | variable()
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| {as, field(), alias()}
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| {'fun', atom(), list(field())}).
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-export_type([select/0]).
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%% Dialyzer gives up on the generated code.
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%% probably due to stack depth, or inlines.
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-dialyzer({nowarn_function, [parse_select/1]}).
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%% Parse one select statement.
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-spec(parse_select(string() | binary())
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-> {ok, select()} | {parse_error, term()} | {lex_error, term()}).
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parse_select(Sql) ->
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try case rulesql:parsetree(Sql) of
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{ok, {select, Clauses}} ->
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{ok, #select{
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is_foreach = false,
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fields = get_value(fields, Clauses),
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doeach = [],
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incase = {},
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from = get_value(from, Clauses),
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where = get_value(where, Clauses)
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}};
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{ok, {foreach, Clauses}} ->
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{ok, #select{
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is_foreach = true,
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fields = get_value(fields, Clauses),
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doeach = get_value(do, Clauses, []),
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incase = get_value(incase, Clauses, {}),
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from = get_value(from, Clauses),
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where = get_value(where, Clauses)
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}};
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Error -> Error
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end
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catch
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_Error:Reason:StackTrace ->
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{parse_error, {Reason, StackTrace}}
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end.
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-spec(select_fields(select()) -> list(field())).
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select_fields(#select{fields = Fields}) ->
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Fields.
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-spec(select_is_foreach(select()) -> boolean()).
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select_is_foreach(#select{is_foreach = IsForeach}) ->
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IsForeach.
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-spec(select_doeach(select()) -> list(field())).
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select_doeach(#select{doeach = DoEach}) ->
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DoEach.
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-spec(select_incase(select()) -> list(field())).
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select_incase(#select{incase = InCase}) ->
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InCase.
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-spec(select_from(select()) -> list(binary())).
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select_from(#select{from = From}) ->
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From.
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-spec(select_where(select()) -> tuple()).
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select_where(#select{where = Where}) ->
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Where.
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