/
float.go
107 lines (93 loc) · 2.74 KB
/
float.go
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// Copyright 2017 The Cockroach 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 settings
import (
"math"
"sync/atomic"
"github.com/pkg/errors"
)
// FloatSetting is the interface of a setting variable that will be
// updated automatically when the corresponding cluster-wide setting
// of type "float" is updated.
type FloatSetting struct {
defaultValue float64
v uint64
validateFn func(float64) error
}
var _ Setting = &FloatSetting{}
// Get retrieves the float value in the setting.
func (f *FloatSetting) Get() float64 {
return math.Float64frombits(atomic.LoadUint64(&f.v))
}
func (f *FloatSetting) String() string {
return EncodeFloat(f.Get())
}
// Typ returns the short (1 char) string denoting the type of setting.
func (*FloatSetting) Typ() string {
return "f"
}
// Validate that a value conforms with the validation function.
func (f *FloatSetting) Validate(v float64) error {
if f.validateFn != nil {
if err := f.validateFn(v); err != nil {
return err
}
}
return nil
}
func (f *FloatSetting) set(v float64) error {
if err := f.Validate(v); err != nil {
return err
}
atomic.StoreUint64(&f.v, math.Float64bits(v))
return nil
}
func (f *FloatSetting) setToDefault() {
if err := f.set(f.defaultValue); err != nil {
panic(err)
}
}
// RegisterFloatSetting defines a new setting with type float.
func RegisterFloatSetting(key, desc string, defaultValue float64) *FloatSetting {
return RegisterValidatedFloatSetting(key, desc, defaultValue, nil)
}
// RegisterValidatedFloatSetting defines a new setting with type float.
func RegisterValidatedFloatSetting(
key, desc string, defaultValue float64, validateFn func(float64) error,
) *FloatSetting {
if validateFn != nil {
if err := validateFn(defaultValue); err != nil {
panic(errors.Wrap(err, "invalid default"))
}
}
setting := &FloatSetting{
defaultValue: defaultValue,
validateFn: validateFn,
}
register(key, desc, setting)
return setting
}
// TestingSetFloat returns a mock, unregistered float setting for testing. See
// TestingSetBool for more details.
func TestingSetFloat(s **FloatSetting, v float64) func() {
saved := *s
tmp := &FloatSetting{}
if err := tmp.set(v); err != nil {
panic(err)
}
*s = tmp
return func() {
*s = saved
}
}