60 lines
1.5 KiB
Go
60 lines
1.5 KiB
Go
package bluetooth
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import (
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"errors"
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"github.com/JuulLabs-OSS/cbgo"
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)
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// Scan starts a BLE scan. It is stopped by a call to StopScan. A common pattern
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// is to cancel the scan when a particular device has been found.
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func (a *Adapter) Scan(callback func(*Adapter, ScanResult)) (err error) {
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if callback == nil {
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return errors.New("must provide callback to Scan function")
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}
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if a.cancelChan != nil {
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return errors.New("already calling Scan function")
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}
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a.peripheralFoundHandler = callback
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// Channel that will be closed when the scan is stopped.
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// Detecting whether the scan is stopped can be done by doing a non-blocking
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// read from it. If it succeeds, the scan is stopped.
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cancelChan := make(chan struct{})
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a.cancelChan = cancelChan
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a.cm.Scan(nil, &cbgo.CentralManagerScanOpts{
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AllowDuplicates: true,
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})
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for {
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// Check whether the scan is stopped. This is necessary to avoid a race
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// condition between the signal channel and the cancelScan channel when
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// the callback calls StopScan() (no new callbacks may be called after
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// StopScan is called).
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select {
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case <-cancelChan:
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// stop scanning here?
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return nil
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default:
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}
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}
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}
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// StopScan stops any in-progress scan. It can be called from within a Scan
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// callback to stop the current scan. If no scan is in progress, an error will
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// be returned.
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func (a *Adapter) StopScan() error {
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if a.cancelChan != nil {
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return errors.New("already calling Scan function")
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}
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a.cm.StopScan()
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close(a.cancelChan)
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a.cancelChan = nil
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return nil
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}
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