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