forked from TrueCloudLab/distribution
58 lines
1.3 KiB
Go
58 lines
1.3 KiB
Go
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package swift
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import (
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"io"
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"time"
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)
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// An io.ReadCloser which obeys an idle timeout
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type timeoutReader struct {
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reader io.ReadCloser
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timeout time.Duration
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cancel func()
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}
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// Returns a wrapper around the reader which obeys an idle
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// timeout. The cancel function is called if the timeout happens
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func newTimeoutReader(reader io.ReadCloser, timeout time.Duration, cancel func()) *timeoutReader {
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return &timeoutReader{
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reader: reader,
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timeout: timeout,
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cancel: cancel,
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}
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}
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// Read reads up to len(p) bytes into p
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//
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// Waits at most for timeout for the read to complete otherwise returns a timeout
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func (t *timeoutReader) Read(p []byte) (int, error) {
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// FIXME limit the amount of data read in one chunk so as to not exceed the timeout?
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// Do the read in the background
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type result struct {
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n int
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err error
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}
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done := make(chan result, 1)
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go func() {
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n, err := t.reader.Read(p)
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done <- result{n, err}
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}()
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// Wait for the read or the timeout
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select {
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case r := <-done:
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return r.n, r.err
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case <-time.After(t.timeout):
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t.cancel()
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return 0, TimeoutError
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}
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panic("unreachable") // for Go 1.0
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}
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// Close the channel
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func (t *timeoutReader) Close() error {
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return t.reader.Close()
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}
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// Check it satisfies the interface
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var _ io.ReadCloser = &timeoutReader{}
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