69 lines
1.6 KiB
Go
69 lines
1.6 KiB
Go
package main
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import (
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"fmt"
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"io"
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"io/ioutil"
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"os"
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)
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type WriteSyncer interface {
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io.Writer
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Sync() error
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}
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type Sink interface {
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WriteSyncer
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io.Closer
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}
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func newFileSink(path string) (Sink, error) {
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return os.OpenFile(path, os.O_WRONLY|os.O_APPEND|os.O_CREATE, 0666)
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}
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type Sink1 struct{ name string }
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func (s Sink1) Write(b []byte) (int, error) { println("in Write"); return 0, nil }
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func (s Sink1) Sync() error { println("in Sync"); return nil }
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func (s Sink1) Close() error { println("in Close", s.name); return nil }
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func newS1(name string) Sink { return Sink1{name} }
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func newS1p(name string) Sink { return &Sink1{name} }
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type Sink2 struct{ name string }
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func (s *Sink2) Write(b []byte) (int, error) { println("in Write"); return 0, nil }
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func (s *Sink2) Sync() error { println("in Sync"); return nil }
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func (s *Sink2) Close() error { println("in Close", s.name); return nil }
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func newS2(name string) Sink { return Sink1{name} }
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func main() {
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tmpfile, err := ioutil.TempFile("", "xxx")
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if err != nil {
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panic(err)
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}
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defer os.Remove(tmpfile.Name())
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closers := []io.Closer{}
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sink, err := newFileSink(tmpfile.Name())
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if err != nil {
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panic(err)
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}
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closers = append(closers, sink)
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s1p := newS1p("ptr")
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s1 := newS1("struct")
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s2 := newS2("ptr2")
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closers = append(closers, s1p, s1, s2)
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for _, closer := range closers {
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fmt.Println(closer.Close())
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}
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}
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// Output:
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// <nil>
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// in Close ptr
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// <nil>
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// in Close struct
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// <nil>
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// in Close ptr2
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// <nil>
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