class LeaseHelper
Defined at line 103 of file ../../sdk/lib/driver/power/cpp/power-support.h
|LeaseHelper| wraps the collection of channels that represents a power
element. When used with |CreateLeaseHelper| the caller just supplies
the level of the required element(s) and dependency token(s). The caller
does not need to create an element it manages to get the dependencies
to the level it needs, instead it can use the |LeaseHelper| returned from
|CreateLeaseHelper|.
The |LeaseHelper| runs an element internally and exposes a convenient
interface, |AcquireLease| which leases the wrapped element at the "on"
state and consequentally drives the dependencies to their desired state.
Public Methods
void LeaseHelper (const std::string & lease_name, fidl::ClientEnd<fuchsia_power_broker::ElementControl> element_control, fidl::ClientEnd<fuchsia_power_broker::Lessor> lessor, fidl::ServerEnd<fuchsia_power_broker::ElementRunner> element_runner_server, async_dispatcher_t * dispatcher, fit::function<void ()> error_callback, inspect::Node * parent)Creates a |LeaseHelper| running on the supplied |dispatcher|. The lease
is **not** active when the constructor returns, use |AcquireLease| for.
this. Blocking the dispatcher while waiting for the callback from
|AcquireLease| will result in a deadlock.
|error_callback| is called if |LeaseHelper| encounters an error running
its wrapped power element. If the error handler is invokes, the
|LeaseHelper| should be dropped and a new one created.
Defined at line 113 of file ../../sdk/lib/driver/power/cpp/power-support.h
void AcquireLease (fit::function<void (fidl::Result<fuchsia_power_broker::Lessor::Lease> &)> callback)Trigger the lease acquisition. The lease is **created**, but not active,
when |callback| is invoked. The lease is active when
`fuchsia.power.broker/LeaseControl` channel given to |callback| reports
`fuchsia.power.broker/LeaseStatus::Satisfied` from
`fuchsia.power.broker/LeaseControl.WatchStatus()`.
Release the lease by closing the `LeaseControl` channel. |AcquireLease|
can be called more than once and creates a lease for each call.
Defined at line 615 of file ../../sdk/lib/driver/power/cpp/power-support.cc