65 lines
1.9 KiB
Go
65 lines
1.9 KiB
Go
package iter
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import (
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"sync"
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"github.com/sourcegraph/conc/internal/multierror"
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)
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// Mapper is an Iterator with a result type R. It can be used to configure
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// the behaviour of Map and MapErr. The zero value is safe to use with
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// reasonable defaults.
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//
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// Mapper is also safe for reuse and concurrent use.
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type Mapper[T, R any] Iterator[T]
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// Map applies f to each element of input, returning the mapped result.
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//
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// Map always uses at most runtime.GOMAXPROCS goroutines. For a configurable
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// goroutine limit, use a custom Mapper.
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func Map[T, R any](input []T, f func(*T) R) []R {
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return Mapper[T, R]{}.Map(input, f)
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}
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// Map applies f to each element of input, returning the mapped result.
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//
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// Map uses up to the configured Mapper's maximum number of goroutines.
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func (m Mapper[T, R]) Map(input []T, f func(*T) R) []R {
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res := make([]R, len(input))
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Iterator[T](m).ForEachIdx(input, func(i int, t *T) {
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res[i] = f(t)
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})
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return res
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}
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// MapErr applies f to each element of the input, returning the mapped result
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// and a combined error of all returned errors.
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//
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// Map always uses at most runtime.GOMAXPROCS goroutines. For a configurable
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// goroutine limit, use a custom Mapper.
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func MapErr[T, R any](input []T, f func(*T) (R, error)) ([]R, error) {
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return Mapper[T, R]{}.MapErr(input, f)
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}
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// MapErr applies f to each element of the input, returning the mapped result
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// and a combined error of all returned errors.
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//
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// Map uses up to the configured Mapper's maximum number of goroutines.
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func (m Mapper[T, R]) MapErr(input []T, f func(*T) (R, error)) ([]R, error) {
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var (
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res = make([]R, len(input))
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errMux sync.Mutex
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errs error
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)
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Iterator[T](m).ForEachIdx(input, func(i int, t *T) {
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var err error
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res[i], err = f(t)
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if err != nil {
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errMux.Lock()
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// TODO: use stdlib errors once multierrors land in go 1.20
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errs = multierror.Join(errs, err)
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errMux.Unlock()
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}
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})
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return res, errs
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}
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