Official Go implementation of the Ethereum protocol
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go-ethereum/metrics/gauge_float64.go

73 lines
2.0 KiB

package metrics
import (
"math"
"sync/atomic"
)
type GaugeFloat64Snapshot interface {
Value() float64
}
// GaugeFloat64 hold a float64 value that can be set arbitrarily.
type GaugeFloat64 interface {
Snapshot() GaugeFloat64Snapshot
Update(float64)
}
// GetOrRegisterGaugeFloat64 returns an existing GaugeFloat64 or constructs and registers a
// new StandardGaugeFloat64.
func GetOrRegisterGaugeFloat64(name string, r Registry) GaugeFloat64 {
if nil == r {
r = DefaultRegistry
}
return r.GetOrRegister(name, NewGaugeFloat64()).(GaugeFloat64)
}
// NewGaugeFloat64 constructs a new StandardGaugeFloat64.
func NewGaugeFloat64() GaugeFloat64 {
if !Enabled {
return NilGaugeFloat64{}
}
return &StandardGaugeFloat64{}
}
// NewRegisteredGaugeFloat64 constructs and registers a new StandardGaugeFloat64.
func NewRegisteredGaugeFloat64(name string, r Registry) GaugeFloat64 {
c := NewGaugeFloat64()
if nil == r {
r = DefaultRegistry
}
r.Register(name, c)
return c
}
// gaugeFloat64Snapshot is a read-only copy of another GaugeFloat64.
type gaugeFloat64Snapshot float64
// Value returns the value at the time the snapshot was taken.
func (g gaugeFloat64Snapshot) Value() float64 { return float64(g) }
// NilGaugeFloat64 is a no-op Gauge.
type NilGaugeFloat64 struct{}
func (NilGaugeFloat64) Snapshot() GaugeFloat64Snapshot { return NilGaugeFloat64{} }
func (NilGaugeFloat64) Update(v float64) {}
func (NilGaugeFloat64) Value() float64 { return 0.0 }
// StandardGaugeFloat64 is the standard implementation of a GaugeFloat64 and uses
// atomic to manage a single float64 value.
type StandardGaugeFloat64 struct {
floatBits atomic.Uint64
}
// Snapshot returns a read-only copy of the gauge.
func (g *StandardGaugeFloat64) Snapshot() GaugeFloat64Snapshot {
v := math.Float64frombits(g.floatBits.Load())
return gaugeFloat64Snapshot(v)
}
// Update updates the gauge's value.
func (g *StandardGaugeFloat64) Update(v float64) {
g.floatBits.Store(math.Float64bits(v))
}