Unfortunately, the implementation was not thread safe and was not
sticking to the thread local main context.
In addition to this, it is not entirely clear to me how this API should
behave. The current approach is to simply cancel the transition with the
state machine halting in its current state. Instead, it could also make
sense for cancellation to cause the state machine to return a
G_IO_ERROR_CANCELLED.
As such, simply remove the feature for now. If anyone actually has a
good use-case then we can add it again.
In some situations one may want to guarantee that the last steps of an
SSM are run even when the SSM is completed early or failed.
This can easily be done by making fpi_ssm_mark_completed jump to the
next cleanup stage when called (this also includes mark_failed). Due to
the mechanism, it is still possible to explicitly jump cleanup states by
using fpi_ssm_jump_to_state, including a jump to the final state in
order to skip all cleanup states.
These routines assume that any messages is composed of a write and/or
read part. While the API allows sending and receiving as part of one
messages/transfer, it does not permit full duplex operation where data is
both send and received at the same time.
Don't make headers inclusions dependent on each others, given that FpiSsm
depends on FpiUsbTransfer and vice-versa, so fix the dependency cycle by
using forwarded declarations.
Add fpi_ssm_new_full() that allows to pass a name to the state-machine
constructor, not to change all the drivers, provide a fpi_ssm_new() macro
that stringifies the nr_parameters value (usually an enum value) as the name
so that we can use it for better debugging.
Add a GCancellable parameter to fpi_ssm_nex_state_delayed and
fpi_ssm_jump_to_state_delayed() so that it's possible to cancel an action
from the caller and in case the driver wants to cancel a delayed operation
when a device action has been cancelled.
This allows to have an automatic cleanup of the timeout source when the
the callback is reached and to avoid to do further state changes in the
middle.
Allow to pass a double-pointer to be nullified as the transfer data in order
to mark it as NULL when the transfer is done.
This is useful if we're keeping the transfer around in order to check that
no one is currently running.
Use the same approach of GTask, making possible to set the data from a
function. Givent the fact that a SSM has now a device parameter, it's
generally not needed to pass an extra data value.
In such case make it possible to set it and to define a destroy-notify
function to handle its destruction when freeing the SSM.
This is a rewrite of the core based on GObject and Gio. This commit
breaks the build in a lot of ways, but basic functionality will start
working again with the next commits.
Pass the struct fp_dev and user_data to fpi_ssm callbacks, so that we
might be able to get rid of the fpi_ssm_get_user_data(), and
fpi_ssm_get_dev() as most drivers just get those from the ssm anyway
in their callbacks.
