зеркало из https://github.com/github/vitess-gh.git
42 строки
901 B
Go
42 строки
901 B
Go
package mysqlctl
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import (
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log "github.com/golang/glog"
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)
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type MapFunc func(index int) error
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// ConcurrentMap applies fun in a concurrent manner on integers from 0
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// to n-1 (they are assumed to be indexes of some slice containing
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// items to be processed). The first error returned by a fun
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// application will returned (subsequent errors will only be
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// logged). It will use concurrency goroutines.
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func ConcurrentMap(concurrency, n int, fun MapFunc) error {
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errors := make(chan error)
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work := make(chan int, n)
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for i := 0; i < n; i++ {
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work <- i
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}
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close(work)
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for j := 0; j < concurrency; j++ {
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go func() {
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for i := range work {
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errors <- fun(i)
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}
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}()
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}
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var err error
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for i := 0; i < n; i++ {
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if e := <-errors; e != nil {
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if err != nil {
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log.Errorf("multiple errors, this one happened but it won't be returned: %v", err)
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}
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err = e
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}
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}
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return err
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}
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