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package utils
import (
"io"
"sync"
)
// This wraps a writer and ensures that before we actually write anything we call a given function first
type OnceWriter struct {
writer io.Writer
once sync.Once
f func()
}
var _ io.Writer = &OnceWriter{}
func NewOnceWriter(writer io.Writer, f func()) *OnceWriter {
return &OnceWriter{
writer: writer,
f: f,
}
}
func (self *OnceWriter) Write(p []byte) (n int, err error) {
self.once.Do(func() {
self.f()
})
return self.writer.Write(p)
}
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