Linux-specific implementation for I/O controller. More...

#include <poll_io_controller.h>

Inheritance diagram for ugcs::vsm::internal::Poll_io_controller:

Classes
struct	Io_cb
	Control block for I/O operation. More...

Public Member Functions
virtual void	Enable () override
	Enable the controller. More...

virtual void	Disable () override
	Disable the controller. More...

virtual void	Register_handle (File_processor::Stream::Native_handle &) override
	Register new opened file handle. More...

virtual void	Unregister_handle (File_processor::Stream::Native_handle &) override
	Unregister previously registered file handle. More...

void	Delete_handle (int fd)
	Delete handle. More...

bool	Queue_operation (Io_cb &io_cb)
	Queue IO operation. More...

bool	Cancel_operation (Io_cb &io_cb)
	Cancel pending operation. More...

Additional Inherited Members
Static Public Member Functions inherited from ugcs::vsm::File_processor::Native_controller
static std::unique_ptr < Native_controller >	Create ()
	Create controller instance. More...

Detailed Description

Linux-specific implementation for I/O controller.

Member Function Documentation

bool ugcs::vsm::internal::Poll_io_controller::Cancel_operation ( Io_cb & io_cb )

Cancel pending operation.

Parameters

io_cb Operation control block.

Returns: True if cancelled, false if not cancelled (e.g. too late).

void ugcs::vsm::internal::Poll_io_controller::Delete_handle ( int fd )

Delete handle.

Possibly deferred. This is a workaround of kernel panic bug in OSX. The scenario: 1) create pipe with descriptors p1, p2. 2) open serial port with descriptor fd. 3) poll on two descriptors p1 and fd in separate thread. 4) issue write on p2. This triggers read event on p1 and wakes up poll(). 5) close(fd)

Results:

When (4) and (5) are close enough poll does not wake up and close(fd) blocks and triggers kernel panic. This does not happen 100% of time but if the above code is put into loop it takes ~20-100 iterations to trigger.
When (4) and (5) are >10ms apart the poll wakes up and close succeeds.
If close(fd) is called before write(p2) then I could not repeat the kernel panic. Solution:

Do not close the fd while it is in polling state. Close it after poll returns.

virtual void ugcs::vsm::internal::Poll_io_controller::Disable ( )

overridevirtual

Disable the controller.

Implements ugcs::vsm::File_processor::Native_controller.

virtual void ugcs::vsm::internal::Poll_io_controller::Enable ( )

overridevirtual

Enable the controller.

Implements ugcs::vsm::File_processor::Native_controller.

bool ugcs::vsm::internal::Poll_io_controller::Queue_operation ( Io_cb & io_cb )

Queue IO operation.

The provided callback is called when the operation completes with Io_cb structure filled.