71 lines
1.4 KiB
Go
71 lines
1.4 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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// 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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bytes int64
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replayFirst bool
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readFirst bool
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first byte
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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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//
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// It also has a 1 byte buffer which can be reset with the Reset() method.
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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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}
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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) (n int, err error) {
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if len(p) == 0 {
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return 0, nil
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}
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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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resetTimer(t.timer, t.timeout)
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if t.replayFirst {
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p[0] = t.first
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t.replayFirst = false
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n = 1
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err = nil
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} else {
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n, err = t.reader.Read(p)
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if !t.readFirst && n > 0 {
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t.first = p[0]
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t.readFirst = true
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}
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t.bytes += int64(n)
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}
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resetTimer(t.timer, t.timeout)
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return
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}
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// Resets the buffer if only 1 byte read
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//
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// Returns true if successful
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func (t *watchdogReader) Reset() bool {
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switch t.bytes {
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case 0:
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t.replayFirst = false
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return true
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case 1:
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t.replayFirst = true
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return true
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default:
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return false
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}
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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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