Class MissionClient

Namespace: MavNet.PX4.Missions

Assembly: MavNet.PX4.dll

Implements the MAVLink mission-protocol upload and download state machines for one (target, MavNet.Protocol.Generated.Enums.MavMissionType) pair on top of an IMavlinkConnection. One MissionClient handles one mission type (waypoints, fence, or rally) — Vehicle owns one per type so the three transactions can run independently per spec.

Upload. Caller invokes UploadAsync(IReadOnlyList<MissionItem>, CancellationToken). We send MISSION_COUNT, then for each MISSION_REQUEST_INT (or its deprecated MISSION_REQUEST sibling that ArduPilot still emits) we reply with a MISSION_ITEM_INT. After the final item the vehicle answers with MISSION_ACK, which terminates the transaction.

Download. Caller invokes DownloadAsync(CancellationToken). We send MISSION_REQUEST_LIST, the vehicle responds with MISSION_COUNT (carrying the on-vehicle opaque_id), then we send a MISSION_REQUEST_INT per item in order and collect each MISSION_ITEM_INT reply. After the final item we send a final MISSION_ACK(MAV_MISSION_ACCEPTED) per spec to close the transaction.

Timing. Per the MAVLink spec: 1500 ms default timeout, 250 ms for the inner item loop, max 5 retries. Defaults are baked in but all three are constructor-injectable so tests stay sub-second.

Out-of-sequence is not an error. If the vehicle re-requests an earlier seq during upload, we re-answer with that item rather than abort. If the vehicle answers with an unexpected seq during download, we just ignore it and let the watchdog re-request. Per spec only timeout exhaustion and a non-Accepted MISSION_ACK cause a transaction to fail.

Threading. Inbound events fire on the connection's receive thread. All mutable state is guarded by an internal lock; the lock window only covers the state mutation, never the awaiter's continuation (the result Task uses RunContinuationsAsynchronously).

Single-flight. Only one transaction may be in flight per MissionClient, regardless of direction. A concurrent UploadAsync(IReadOnlyList<MissionItem>, CancellationToken) or DownloadAsync(CancellationToken) throws InvalidOperationException.

public sealed class MissionClient : IDisposable

Inheritance: object

MissionClient

Implements: IDisposable

Inherited Members: object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.ReferenceEquals(object, object)

object.ToString()

Constructors

MissionClient(IMavlinkConnection, byte, byte, MavMissionType, TimeSpan?, TimeSpan?, int, ILogger?)

Create a client bound to one target and one mission type.

public MissionClient(IMavlinkConnection connection, byte targetSystem, byte targetComponent, MavMissionType missionType = MavMissionType.Mission, TimeSpan? defaultTimeout = null, TimeSpan? itemTimeout = null, int maxRetries = 5, ILogger? logger = null)

Parameters

connection IMavlinkConnection: Transport — subscribes to its mission events for the lifetime of this client.
targetSystem byte: Sender system id we accept inbound mission messages from, and the target on outbound.
targetComponent byte: Sender component id we accept inbound mission messages from, and the target on outbound.
missionType MavMissionType: Which on-vehicle plan this client manages.
defaultTimeout TimeSpan?: Per-message timeout. Defaults to 1500 ms (spec).
itemTimeout TimeSpan?: Inner item-loop timeout. Defaults to 250 ms (spec).
maxRetries int: Max retries per message before failing as Timeout. Defaults to 5 (spec).
logger ILogger: Optional. Null = no logging.

Properties

DefaultTimeout

Default per-message timeout (1500 ms per spec unless overridden).

public TimeSpan DefaultTimeout { get; }

Property Value

TimeSpan

IsBusy

True iff a transaction (upload, download, …) is currently in flight.

public bool IsBusy { get; }

Property Value

bool

ItemTimeout

Item-request timeout (250 ms per spec unless overridden) — used for the inner request/response loop after the first MISSION_REQUEST_INT arrives.

public TimeSpan ItemTimeout { get; }

Property Value

TimeSpan

MaxRetries

Max retries per message (5 per spec unless overridden).

public int MaxRetries { get; }

Property Value

int

MissionType

The mission type this client handles.

public MavMissionType MissionType { get; }

Property Value

MavMissionType

Methods

ClearAsync(CancellationToken)

Clear the on-vehicle plan for this client's MissionType. Sends MISSION_CLEAR_ALL and awaits MISSION_ACK. Resolves when the vehicle ACKs, after retry/timeout exhaustion, on cancellation, or on disposal.

public Task<MissionClearResult> ClearAsync(CancellationToken ct = default)

Parameters

ct CancellationToken: Cancellation. On firing, completes Cancelled.

Returns

Task<MissionClearResult>

Exceptions

InvalidOperationException: Another transaction is already in flight.
ObjectDisposedException: This client has been disposed.

Dispose()

Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.

public void Dispose()

DownloadAsync(CancellationToken)

Download the on-vehicle plan for this client's MissionType. Resolves when the final MISSION_ITEM_INT arrives and we've sent the closing MISSION_ACK(Accepted), after retry/timeout exhaustion, on cancellation, or on disposal.

public Task<MissionDownloadResult> DownloadAsync(CancellationToken ct = default)

Parameters

ct CancellationToken: Cancellation. On firing, the transaction completes with Cancelled; whatever partial items were collected are discarded (Items is empty).

Returns

Task<MissionDownloadResult>

Exceptions

InvalidOperationException: Another transaction is already in flight.
ObjectDisposedException: This client has been disposed.

UploadAsync(IReadOnlyList<MissionItem>, CancellationToken)

Upload items to the target vehicle for this client's MissionType. Resolves when the vehicle responds with MISSION_ACK, after retry/timeout budget exhaustion, on cancellation, or on disposal.

public Task<MissionUploadResult> UploadAsync(IReadOnlyList<MissionItem> items, CancellationToken ct = default)

Parameters

items IReadOnlyList<MissionItem>: Items in order. Count must fit in a ushort. An empty list is accepted (the vehicle treats MISSION_COUNT=0 as a clear).
ct CancellationToken: Cancellation. On firing, the transaction completes with Cancelled; the vehicle may be left in a partial-upload state and a follow-up clear/re-upload is advisable.

Returns

Task<MissionUploadResult>

Exceptions

InvalidOperationException: Another transaction is already in flight.
ObjectDisposedException: This client has been disposed.
ArgumentNullException: If items is null.
ArgumentException: If items exceeds ushort.MaxValue.