90 lines
1.8 KiB
Go
90 lines
1.8 KiB
Go
package ticker
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import (
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"fmt"
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"sync"
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)
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// IterationHandler is a callback of a certain block advance.
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type IterationHandler func()
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// IterationsTicker represents a fixed tick number block timer.
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//
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// It can tick the blocks and perform certain actions
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// on block time intervals.
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type IterationsTicker struct {
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m sync.Mutex
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curr uint64
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period uint64
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times uint64
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h IterationHandler
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}
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// NewIterationsTicker creates a new IterationsTicker.
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//
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// It guaranties that a handler would be called the
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// specified amount of times in the specified amount
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// of blocks. After the last meaningful Tick, IterationsTicker
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// becomes no-op timer.
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//
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// Returns an error only if times is greater than totalBlocks.
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func NewIterationsTicker(totalBlocks uint64, times uint64, h IterationHandler) (*IterationsTicker, error) {
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period := totalBlocks / times
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if period == 0 {
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return nil, fmt.Errorf("impossible to tick %d times in %d blocks",
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times, totalBlocks,
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)
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}
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var curr uint64
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// try to make handler calls as rare as possible
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if totalBlocks%times != 0 {
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extraBlocks := (period+1)*times - totalBlocks
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if period >= extraBlocks {
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curr = extraBlocks + (period-extraBlocks)/2
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period++
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}
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}
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return &IterationsTicker{
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curr: curr,
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period: period,
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times: times,
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h: h,
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}, nil
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}
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// Tick ticks one block in the IterationsTicker.
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//
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// Returns `false` if the timer has finished its operations
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// and there will be no more handler calls.
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// Calling Tick after the returned `false` is safe, no-op
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// and also returns `false`.
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func (ft *IterationsTicker) Tick() bool {
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ft.m.Lock()
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defer ft.m.Unlock()
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if ft.times == 0 {
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return false
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}
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ft.curr++
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if ft.curr%ft.period == 0 {
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ft.h()
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ft.times--
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if ft.times == 0 {
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return false
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}
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}
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return true
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}
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