kacerrandClaude Fable 5
7219eb5a23
Includes solved 02-worker-pool and 09-safe-counter (mutex, atomic, sharded). Co-Authored-By: Claude Fable 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01GbnJj9ZqEx9nUvzkjdwfMq
50 lines
1.3 KiB
Go
50 lines
1.3 KiB
Go
// Exercise 07 — Fan-in / Merge Channels
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//
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// ASSIGNMENT
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// ----------
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// Implement Merge(ctx, chs...):
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//
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// 1. Returns a single channel carrying every value from every input channel.
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// 2. The output channel is CLOSED once all input channels are closed and
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// drained.
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// 3. If ctx is cancelled, Merge stops forwarding, and all its internal
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// goroutines exit even if inputs never close and even if nobody reads
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// the output anymore. (No goroutine leaks — the tests count goroutines.)
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// 4. Order across inputs is unspecified.
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//
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// Run the tests: go test -race ./07-fan-in/
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package main
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import (
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"context"
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"fmt"
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)
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// Merge fans in all input channels into one output channel.
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// TODO: implement me.
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func Merge[T any](ctx context.Context, chs ...<-chan T) <-chan T {
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out := make(chan T)
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// TODO:
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// - one forwarder goroutine per input channel
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// - each forward is a select: {out <- v} vs {<-ctx.Done()}
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// - reading the input must ALSO select on ctx.Done()
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// - closer goroutine: wg.Wait(); close(out)
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return out
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}
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func main() {
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gen := func(vals ...int) <-chan int {
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ch := make(chan int)
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go func() {
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defer close(ch)
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for _, v := range vals {
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ch <- v
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}
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}()
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return ch
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}
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for v := range Merge(context.Background(), gen(1, 2, 3), gen(10, 20), gen(100)) {
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fmt.Println(v)
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}
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}
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