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

73 lines
2.1 KiB

package metrics
type HistogramSnapshot interface {
SampleSnapshot
}
// Histogram calculates distribution statistics from a series of int64 values.
type Histogram interface {
Clear()
Update(int64)
Snapshot() HistogramSnapshot
}
// GetOrRegisterHistogram returns an existing Histogram or constructs and
// registers a new StandardHistogram.
func GetOrRegisterHistogram(name string, r Registry, s Sample) Histogram {
if nil == r {
r = DefaultRegistry
}
return r.GetOrRegister(name, func() Histogram { return NewHistogram(s) }).(Histogram)
}
// GetOrRegisterHistogramLazy returns an existing Histogram or constructs and
// registers a new StandardHistogram.
func GetOrRegisterHistogramLazy(name string, r Registry, s func() Sample) Histogram {
if nil == r {
r = DefaultRegistry
}
return r.GetOrRegister(name, func() Histogram { return NewHistogram(s()) }).(Histogram)
}
// NewHistogram constructs a new StandardHistogram from a Sample.
func NewHistogram(s Sample) Histogram {
if !Enabled {
return NilHistogram{}
}
return &StandardHistogram{sample: s}
}
// NewRegisteredHistogram constructs and registers a new StandardHistogram from
// a Sample.
func NewRegisteredHistogram(name string, r Registry, s Sample) Histogram {
c := NewHistogram(s)
if nil == r {
r = DefaultRegistry
}
r.Register(name, c)
return c
}
// NilHistogram is a no-op Histogram.
type NilHistogram struct{}
func (NilHistogram) Clear() {}
func (NilHistogram) Snapshot() HistogramSnapshot { return (*emptySnapshot)(nil) }
func (NilHistogram) Update(v int64) {}
// StandardHistogram is the standard implementation of a Histogram and uses a
// Sample to bound its memory use.
type StandardHistogram struct {
sample Sample
}
// Clear clears the histogram and its sample.
func (h *StandardHistogram) Clear() { h.sample.Clear() }
// Snapshot returns a read-only copy of the histogram.
func (h *StandardHistogram) Snapshot() HistogramSnapshot {
return h.sample.Snapshot()
}
// Update samples a new value.
func (h *StandardHistogram) Update(v int64) { h.sample.Update(v) }