Source: valueparser.go in package github.com/prometheus/procfs/internal/util

Copyright 2019 The Prometheus 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 util

import (
	"strconv"
)

TODO(mdlayher): util packages are an anti-pattern and this should be moved somewhere else that is more focused in the future.

A ValueParser enables parsing a single string into a variety of data types in a concise and safe way. The Err method must be invoked after invoking any other methods to ensure a value was successfully parsed.

type ValueParser struct {
	v   string
	err error
}

NewValueParser creates a ValueParser using the input string.

func NewValueParser(v string) *ValueParser {
	return &ValueParser{v: v}
}

Int interprets the underlying value as an int and returns that value.

func (vp *ValueParser) Int() int { return int(vp.int64()) }

PInt64 interprets the underlying value as an int64 and returns a pointer to that value.

func (vp *ValueParser) PInt64() *int64 {
	if vp.err != nil {
		return nil
	}

	v := vp.int64()
	return &v
}

int64 interprets the underlying value as an int64 and returns that value. TODO: export if/when necessary.

func (vp *ValueParser) int64() int64 {
	if vp.err != nil {
		return 0
	}

A base value of zero makes ParseInt infer the correct base using the string's prefix, if any.

	const base = 0
	v, err := strconv.ParseInt(vp.v, base, 64)
	if err != nil {
		vp.err = err
		return 0
	}

	return v
}

PUInt64 interprets the underlying value as an uint64 and returns a pointer to that value.

func (vp *ValueParser) PUInt64() *uint64 {
	if vp.err != nil {
		return nil
	}

A base value of zero makes ParseInt infer the correct base using the string's prefix, if any.

	const base = 0
	v, err := strconv.ParseUint(vp.v, base, 64)
	if err != nil {
		vp.err = err
		return nil
	}

	return &v
}

Err returns the last error, if any, encountered by the ValueParser.

func (vp *ValueParser) Err() error {
	return vp.err