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author | Péter Szilágyi <peterke@gmail.com> | 2015-06-22 17:00:55 +0800 |
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committer | Péter Szilágyi <peterke@gmail.com> | 2015-06-24 23:34:04 +0800 |
commit | 7bd71fa80071f86ca86ed7ef64ab51c88cabe7d4 (patch) | |
tree | 9f770d2f59ca1a3053ebf7aa7921a122aa3bc388 /Godeps/_workspace/src/github.com/rcrowley/go-metrics/counter.go | |
parent | 7f92e708c504e1c4a7382c68b5a4ed68db9c8deb (diff) | |
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godeps: pull in go-metrics
Diffstat (limited to 'Godeps/_workspace/src/github.com/rcrowley/go-metrics/counter.go')
-rw-r--r-- | Godeps/_workspace/src/github.com/rcrowley/go-metrics/counter.go | 112 |
1 files changed, 112 insertions, 0 deletions
diff --git a/Godeps/_workspace/src/github.com/rcrowley/go-metrics/counter.go b/Godeps/_workspace/src/github.com/rcrowley/go-metrics/counter.go new file mode 100644 index 000000000..bb7b039cb --- /dev/null +++ b/Godeps/_workspace/src/github.com/rcrowley/go-metrics/counter.go @@ -0,0 +1,112 @@ +package metrics + +import "sync/atomic" + +// Counters hold an int64 value that can be incremented and decremented. +type Counter interface { + Clear() + Count() int64 + Dec(int64) + Inc(int64) + Snapshot() Counter +} + +// GetOrRegisterCounter returns an existing Counter or constructs and registers +// a new StandardCounter. +func GetOrRegisterCounter(name string, r Registry) Counter { + if nil == r { + r = DefaultRegistry + } + return r.GetOrRegister(name, NewCounter).(Counter) +} + +// NewCounter constructs a new StandardCounter. +func NewCounter() Counter { + if UseNilMetrics { + return NilCounter{} + } + return &StandardCounter{0} +} + +// NewRegisteredCounter constructs and registers a new StandardCounter. +func NewRegisteredCounter(name string, r Registry) Counter { + c := NewCounter() + if nil == r { + r = DefaultRegistry + } + r.Register(name, c) + return c +} + +// CounterSnapshot is a read-only copy of another Counter. +type CounterSnapshot int64 + +// Clear panics. +func (CounterSnapshot) Clear() { + panic("Clear called on a CounterSnapshot") +} + +// Count returns the count at the time the snapshot was taken. +func (c CounterSnapshot) Count() int64 { return int64(c) } + +// Dec panics. +func (CounterSnapshot) Dec(int64) { + panic("Dec called on a CounterSnapshot") +} + +// Inc panics. +func (CounterSnapshot) Inc(int64) { + panic("Inc called on a CounterSnapshot") +} + +// Snapshot returns the snapshot. +func (c CounterSnapshot) Snapshot() Counter { return c } + +// NilCounter is a no-op Counter. +type NilCounter struct{} + +// Clear is a no-op. +func (NilCounter) Clear() {} + +// Count is a no-op. +func (NilCounter) Count() int64 { return 0 } + +// Dec is a no-op. +func (NilCounter) Dec(i int64) {} + +// Inc is a no-op. +func (NilCounter) Inc(i int64) {} + +// Snapshot is a no-op. +func (NilCounter) Snapshot() Counter { return NilCounter{} } + +// StandardCounter is the standard implementation of a Counter and uses the +// sync/atomic package to manage a single int64 value. +type StandardCounter struct { + count int64 +} + +// Clear sets the counter to zero. +func (c *StandardCounter) Clear() { + atomic.StoreInt64(&c.count, 0) +} + +// Count returns the current count. +func (c *StandardCounter) Count() int64 { + return atomic.LoadInt64(&c.count) +} + +// Dec decrements the counter by the given amount. +func (c *StandardCounter) Dec(i int64) { + atomic.AddInt64(&c.count, -i) +} + +// Inc increments the counter by the given amount. +func (c *StandardCounter) Inc(i int64) { + atomic.AddInt64(&c.count, i) +} + +// Snapshot returns a read-only copy of the counter. +func (c *StandardCounter) Snapshot() Counter { + return CounterSnapshot(c.Count()) +} |