forked from TrueCloudLab/distribution
55 lines
1.3 KiB
Go
55 lines
1.3 KiB
Go
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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var watchdogChunkSize = 1 << 20 // 1 MiB
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// An io.Reader which resets a watchdog timer whenever data is read
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type watchdogReader struct {
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timeout time.Duration
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reader io.Reader
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timer *time.Timer
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chunkSize int
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}
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// Returns a new reader which will kick the watchdog timer whenever data is read
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func newWatchdogReader(reader io.Reader, timeout time.Duration, timer *time.Timer) *watchdogReader {
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return &watchdogReader{
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timeout: timeout,
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reader: reader,
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timer: timer,
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chunkSize: watchdogChunkSize,
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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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func (t *watchdogReader) Read(p []byte) (int, error) {
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//read from underlying reader in chunks not larger than t.chunkSize
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//while resetting the watchdog timer before every read; the small chunk
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//size ensures that the timer does not fire when reading a large amount of
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//data from a slow connection
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start := 0
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end := len(p)
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for start < end {
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length := end - start
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if length > t.chunkSize {
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length = t.chunkSize
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}
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resetTimer(t.timer, t.timeout)
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n, err := t.reader.Read(p[start : start+length])
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start += n
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if n == 0 || err != nil {
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return start, err
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}
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}
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resetTimer(t.timer, t.timeout)
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return start, nil
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}
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// Check it satisfies the interface
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var _ io.Reader = &watchdogReader{}
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