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|
package sync
import (
"context"
"sync"
)
func FanOut[T any](ctx context.Context, in <-chan T, channelCount int, buffer int) []<-chan T {
if in == nil {
// we only expect this to happen during development
panic("in-channel is nil")
}
if channelCount < 1 {
channelCount = 1
}
if buffer < 0 {
buffer = 0
}
chs := make([]chan T, channelCount)
for i := range channelCount {
chs[i] = make(chan T, buffer)
}
go func() {
defer func() {
for _, out := range chs {
close(out)
}
}()
for v := range OrDone(ctx, in) {
for _, out := range chs {
// N.b. this will block if *any* of the out channels has a full buffer
if !CancelOrSend(ctx, out, v) {
return
}
}
}
}()
outs := make([]<-chan T, channelCount)
for i, out := range chs {
outs[i] = out
}
return outs
}
func FanIn[T any](ctx context.Context, buffer int, ins ...<-chan T) <-chan T {
if buffer < 0 {
buffer = 0
}
wg := sync.WaitGroup{}
out := make(chan T, buffer)
for _, in := range ins {
wg.Go(func() {
if in == nil {
return
}
for v := range OrDone(ctx, in) {
if !CancelOrSend(ctx, out, v) {
return
}
}
})
}
go func() {
wg.Wait()
close(out)
}()
return out
}
|
