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Diffstat (limited to 'vendor/golang.org/x/time/rate/sometimes.go')
-rw-r--r-- | vendor/golang.org/x/time/rate/sometimes.go | 67 |
1 files changed, 67 insertions, 0 deletions
diff --git a/vendor/golang.org/x/time/rate/sometimes.go b/vendor/golang.org/x/time/rate/sometimes.go new file mode 100644 index 00000000..6ba99ddb --- /dev/null +++ b/vendor/golang.org/x/time/rate/sometimes.go @@ -0,0 +1,67 @@ +// Copyright 2022 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package rate + +import ( + "sync" + "time" +) + +// Sometimes will perform an action occasionally. The First, Every, and +// Interval fields govern the behavior of Do, which performs the action. +// A zero Sometimes value will perform an action exactly once. +// +// # Example: logging with rate limiting +// +// var sometimes = rate.Sometimes{First: 3, Interval: 10*time.Second} +// func Spammy() { +// sometimes.Do(func() { log.Info("here I am!") }) +// } +type Sometimes struct { + First int // if non-zero, the first N calls to Do will run f. + Every int // if non-zero, every Nth call to Do will run f. + Interval time.Duration // if non-zero and Interval has elapsed since f's last run, Do will run f. + + mu sync.Mutex + count int // number of Do calls + last time.Time // last time f was run +} + +// Do runs the function f as allowed by First, Every, and Interval. +// +// The model is a union (not intersection) of filters. The first call to Do +// always runs f. Subsequent calls to Do run f if allowed by First or Every or +// Interval. +// +// A non-zero First:N causes the first N Do(f) calls to run f. +// +// A non-zero Every:M causes every Mth Do(f) call, starting with the first, to +// run f. +// +// A non-zero Interval causes Do(f) to run f if Interval has elapsed since +// Do last ran f. +// +// Specifying multiple filters produces the union of these execution streams. +// For example, specifying both First:N and Every:M causes the first N Do(f) +// calls and every Mth Do(f) call, starting with the first, to run f. See +// Examples for more. +// +// If Do is called multiple times simultaneously, the calls will block and run +// serially. Therefore, Do is intended for lightweight operations. +// +// Because a call to Do may block until f returns, if f causes Do to be called, +// it will deadlock. +func (s *Sometimes) Do(f func()) { + s.mu.Lock() + defer s.mu.Unlock() + if s.count == 0 || + (s.First > 0 && s.count < s.First) || + (s.Every > 0 && s.count%s.Every == 0) || + (s.Interval > 0 && time.Since(s.last) >= s.Interval) { + f() + s.last = time.Now() + } + s.count++ +} |