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package helper
import (
"context"
"io"
)
type ContextReader struct {
ctx context.Context
underlyingReader io.Reader
}
func NewContextReader(ctx context.Context, underlyingReader io.Reader) *ContextReader {
return &ContextReader{
ctx: ctx,
underlyingReader: underlyingReader,
}
}
func (r *ContextReader) Read(b []byte) (int, error) {
if r.canceled() {
return 0, r.err()
}
n, err := r.underlyingReader.Read(b)
if r.canceled() {
err = r.err()
}
return n, err
}
func (r *ContextReader) canceled() bool {
return r.err() != nil
}
func (r *ContextReader) err() error {
return r.ctx.Err()
}
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