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d20381d30b
This is an alternate way of solving the same problem as 4007a902a264e5ff2c3be6b269ade515c9c1c145, but in a nicer way. Compared to using pointers, this approach more obviously preserves the original behaviour, and is arguably more readable than the original code. Credit to @rade for this approach.
63 lines
1.2 KiB
Go
63 lines
1.2 KiB
Go
package app
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import (
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"fmt"
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"github.com/spaolacci/murmur3"
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"github.com/weaveworks/scope/report"
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)
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// Merger is the type for a thing that can merge reports.
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type Merger interface {
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Merge([]report.Report) report.Report
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}
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type dumbMerger struct{}
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// MakeDumbMerger makes a Merger which merges together reports in the simplest possible way.
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func MakeDumbMerger() Merger {
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return dumbMerger{}
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}
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func (dumbMerger) Merge(reports []report.Report) report.Report {
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rpt := report.MakeReport()
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id := murmur3.New64()
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for _, r := range reports {
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rpt = rpt.Merge(r)
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id.Write([]byte(r.ID))
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}
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rpt.ID = fmt.Sprintf("%x", id.Sum64())
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return rpt
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}
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type smartMerger struct{}
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// NewSmartMerger makes a Merger which merges reports in
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// parallel. Speed up comes from the fact that a) most merges are
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// between small reports, and b) we take advantage of available cores.
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func NewSmartMerger() Merger {
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return smartMerger{}
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}
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func (smartMerger) Merge(reports []report.Report) report.Report {
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l := len(reports)
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switch l {
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case 0:
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return report.MakeReport()
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case 1:
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return reports[0]
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}
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c := make(chan report.Report, l)
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for _, r := range reports {
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c <- r
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}
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for ; l > 1; l-- {
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left, right := <-c, <-c
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go func() {
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c <- left.Merge(right)
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}()
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}
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return <-c
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}
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