Enum SessionRequest

pub enum SessionRequest {
    StartTracing {
        payload: StartOptions,
        responder: SessionStartTracingResponder,
    },
    StopTracing {
        payload: StopOptions,
        responder: SessionStopTracingResponder,
    },
    WatchAlert {
        responder: SessionWatchAlertResponder,
    },
    _UnknownMethod {
        ordinal: u64,
        control_handle: SessionControlHandle,
        method_type: MethodType,
    },
}

The session interface used by the trace tool to start/stop/terminate a trace Session.

The trace Session may lightly validate the structure of trace records as it copies them from trace buffers into the output. In particular, it may verify the size of each record header to ensure that the framing of trace records in the data stream is maintained.

The trace Session does not validate the contents of the trace records themselves. For example, it does not try to check argument lengths in events. This ensures that the trace format can be extended without needing to modify the trace Session.

The trace Session must be initialized from the provisioner. It can then be used to start/stop tracing as many times as needed. Dropping the Session will terminate tracing.

Variants

StartTracing

Requests to start tracing with the specified options.

If tracing has already started then the request is ignored, except to send back an error code.

The trace Session acknowledges the request when all registered providers have been started or after TraceConfig.start_timeout_milliseconds milliseconds. One useful reason for the has-started acknowledgement is that the trace program can start a program to trace knowing that all the providers are started.

Fields

payload: StartOptions

responder: SessionStartTracingResponder

StopTracing

Requests to stop tracing.

If tracing has already stopped then this does nothing. Returning a result lets callers know when it’s ok to, for example, start tracing again.

Fields

payload: StopOptions

responder: SessionStopTracingResponder

WatchAlert

Returns the next alert when it arrives.

Alerts received by the Session are queued until a WatchAlert request is received. Alerts are sent to the caller in the order they were received.

WatchAlert requests are also queued until an alert is received and the requests are serviced in the order they were received.

Fields

responder: SessionWatchAlertResponder

_UnknownMethod

An interaction was received which does not match any known method.

Fields

Non-exhaustive enum variants could have additional fields added in future. Therefore, non-exhaustive enum variants cannot be constructed in external crates and cannot be matched against.

ordinal: u64

Ordinal of the method that was called.

control_handle: SessionControlHandle

method_type: MethodType

Implementations

impl SessionRequest

pub fn into_start_tracing( self, ) -> Option<(StartOptions, SessionStartTracingResponder)>

pub fn into_stop_tracing( self, ) -> Option<(StopOptions, SessionStopTracingResponder)>

pub fn into_watch_alert(self) -> Option<SessionWatchAlertResponder>

pub fn method_name(&self) -> &'static str

Name of the method defined in FIDL

Trait Implementations

impl Debug for SessionRequest

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.