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64b0ade171
This swaps github.com/kivikakk/golex for github.com/cznic/golex. The old lexer would have taken 3.5 years to load a set of 5000 test rules (quadratic time complexity for input length), whereas this one takes only 32ms. Furthermore, since the new lexer is embedded differently, this gets rid of the global parser variables and makes the rule loader fully reentrant without a lock.
106 lines
3.5 KiB
Plaintext
106 lines
3.5 KiB
Plaintext
// Copyright 2013 Prometheus Team
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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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package rules
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import (
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"fmt"
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"strconv"
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"strings"
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clientmodel "github.com/prometheus/client_golang/model"
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)
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// Lex is called by the parser generated by "go tool yacc" to obtain each
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// token. The method is opened before the matching rules block and closed at
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// the end of the file.
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func (lexer *RulesLexer) Lex(lval *yySymType) int {
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// Internal lexer states.
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const (
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S_INITIAL = iota
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S_COMMENTS
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)
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// We simulate multiple start symbols for closely-related grammars via dummy tokens. See
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// http://www.gnu.org/software/bison/manual/html_node/Multiple-start_002dsymbols.html
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// Reason: we want to be able to parse lists of named rules as well as single expressions.
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if lexer.startToken != 0 {
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startToken := lexer.startToken
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lexer.startToken = 0
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return startToken
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}
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c := lexer.current
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currentState := 0
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if lexer.empty {
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c, lexer.empty = lexer.getChar(), false
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}
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%}
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D [0-9]
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L [a-zA-Z_:]
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U [smhdwy]
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%x S_COMMENTS
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%yyc c
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%yyn c = lexer.getChar()
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%yyt currentState
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%%
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lexer.buf = lexer.buf[:0] // The code before the first rule executed before every scan cycle (rule #0 / state 0 action)
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"/*" currentState = S_COMMENTS
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<S_COMMENTS>"*/" currentState = S_INITIAL
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<S_COMMENTS>.|\n /* ignore chars within multi-line comments */
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\/\/[^\r\n]*\n /* gobble up one-line comments */
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ALERT|alert return ALERT
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IF|if return IF
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FOR|for return FOR
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WITH|with return WITH
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PERMANENT|permanent return PERMANENT
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BY|by return GROUP_OP
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AVG|SUM|MAX|MIN|COUNT lval.str = lexer.token(); return AGGR_OP
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avg|sum|max|min|count lval.str = strings.ToUpper(lexer.token()); return AGGR_OP
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\<|>|AND|OR|and|or lval.str = strings.ToUpper(lexer.token()); return CMP_OP
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==|!=|>=|<= lval.str = lexer.token(); return CMP_OP
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[+\-] lval.str = lexer.token(); return ADDITIVE_OP
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[*/%] lval.str = lexer.token(); return MULT_OP
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{D}+{U} lval.str = lexer.token(); return DURATION
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{L}({L}|{D})* lval.str = lexer.token(); return IDENTIFIER
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\-?{D}+(\.{D}*)? num, err := strconv.ParseFloat(lexer.token(), 64);
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if (err != nil && err.(*strconv.NumError).Err == strconv.ErrSyntax) {
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panic("Invalid float")
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}
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lval.num = clientmodel.SampleValue(num)
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return NUMBER
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\"(\\.|[^\\"])*\" lval.str = lexer.token()[1:len(lexer.token()) - 1]; return STRING
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\'(\\.|[^\\'])*\' lval.str = lexer.token()[1:len(lexer.token()) - 1]; return STRING
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[{}\[\]()=,] return int(lexer.buf[0])
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[\t\n\r ] /* gobble up any whitespace */
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%%
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lexer.empty = true
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return int(c)
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}
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