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- /*
- Copyright 2019 The Vitess Authors.
- 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.
- */
- package stats
- import (
- "regexp"
- "strings"
- )
- // GetSnakeName calls toSnakeName on the passed in string. It produces
- // a snake-cased name from the provided camel-cased name.
- // It memoizes the transformation and returns the stored result if available.
- func GetSnakeName(name string) string {
- return toSnakeCase(name)
- }
- // toSnakeCase produces a monitoring compliant name from the original.
- // For systems (like Prometheus) that ask for snake-case names.
- // It converts CamelCase to camel_case, and CAMEL_CASE to camel_case.
- // For numbers, it converts 0.5 to v0_5.
- func toSnakeCase(name string) (hyphenated string) {
- snakeMemoizer.Lock()
- defer snakeMemoizer.Unlock()
- if hyphenated = snakeMemoizer.memo[name]; hyphenated != "" {
- return hyphenated
- }
- hyphenated = name
- for _, converter := range snakeConverters {
- hyphenated = converter.re.ReplaceAllString(hyphenated, converter.repl)
- }
- hyphenated = strings.ToLower(hyphenated)
- snakeMemoizer.memo[name] = hyphenated
- return
- }
- var snakeConverters = []struct {
- re *regexp.Regexp
- repl string
- }{
- // example: LC -> L_C (e.g. CamelCase -> Camel_Case).
- {regexp.MustCompile("([a-z])([A-Z])"), "${1}_${2}"},
- // example: CCa -> C_Ca (e.g. CCamel -> C_Camel).
- {regexp.MustCompile("([A-Z])([A-Z][a-z])"), "${1}_${2}"},
- {regexp.MustCompile(`\.`), "_"},
- {regexp.MustCompile("-"), "_"},
- }
- var snakeMemoizer = memoizerType{
- memo: make(map[string]string),
- }
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