class InputReportReaderManager

InputReportReaderManager is used to simplify implementation of input drivers. An input driver may

use InputReportReaderManager to keep track of all upstream readers that want to receive reports.

An upstream driver that wants to read input reports from this device may register with

InputReportReaderManager, which calls CreateReader. When an input report arrives, whether in the

form of HID reports or device readings by polling, etc., the report is pushed to all readers

registered by calling SendReportToAllReaders where it is then translated to

fuchsia_input_report::InputReport.

If kMaxUnreadReports is non-zero, then at most that many reports are allowed to accumulate for

any client before reports are dropped, starting with the oldest ones first.

If kMaxBatchSize is greater than 1, then multiple reports may be batched together before being

sent to clients.

If kMaxBatchSize is greater than 1, then kMaxBatchDelayNs must be set. This is the time in

nanoseconds from receiving the first input report that we will wait before sending a batch to

clients.

This class creates and manages the InputReportReaders. It is able to send reports

to all existing InputReportReaders.

When this class is destructed, all of the InputReportReaders will be freed.

This class is thread-safe.

Typical Usage:

An InputReport Driver should have one InputReportReaderManager member object.

The Driver should also have some form of InputReport object that can be converted to Fidl.

Eg:

class MyTouchScreenDriver {

...

private:

struct TouchScreenReport {

int64_t x;

int64_t y;

void ToFidlInputReport(fidl::WireTableBuilder

<

::fuchsia_input_report::wire::InputReport>

&

input_report, fidl::AnyArena

&

allocator) const;

};

InputReportReaderManager

<TouchScreenReport

> input_report_readers_;

};

See

https://fuchsia.dev/fuchsia-src/development/drivers/concepts/driver_architectures/input_drivers/input?hl=en