VsAppLaunchStateService<TStateDetails>

A small, deterministic state machine that decides when a VS "Play" (Debug/Run) should be considered an application launch. It correlates a Play intent with the next build within a short time window and reports state transitions.

Highlights

• Generic correlation payload TStateDetails chosen by the caller (project path, Guid, tuple, etc.).
• Small API: Start, NotifyBuild, Reset.
• Single StateChanged event with the correlated StateDetails in the payload.
• Time is virtualizable via System.TimeProvider (polyfilled on net48) to make tests deterministic.

API

• Start(TStateDetails details): mark a Play intent and open a short window for a build to begin.
• NotifyBuild(TStateDetails details, BuildNotification notification): inform the state machine of build events for the same details.
  • BuildNotification: Began | Canceled | CompletedSuccess | CompletedFailure
• Reset(): cancel the current wait/build and return to Idle (clears the correlated details).
• event StateChanged(object sender, StateChangedEventArgs<TStateDetails> e): raised on every state transition with TimestampUtc, Previous, Current, StateDetails. The convenience property e.Succeeded is true only when Current == BuildSucceeded.

Options

• Options.BuildWaitWindow (default 8 seconds): time to wait after Start for a build to begin.

States

• Idle
• PlayInvokedPendingBuild
• BuildInProgress
• BuildSucceeded (transient)
• BuildFailed (transient)
• TimedOut (transient)

Mermaid

stateDiagram-v2
  classDef transient stroke-dasharray: 5 5, font-style: italic

  [*] --> Idle
  Idle --> PlayInvokedPendingBuild: Start(details)

  PlayInvokedPendingBuild --> BuildInProgress: NotifyBuild(details,Began)
  PlayInvokedPendingBuild --> TimedOut: after BuildWaitWindow

  BuildInProgress --> BuildSucceeded: NotifyBuild(details,CompletedSuccess)
  BuildInProgress --> BuildFailed: NotifyBuild(details,CompletedFailure)
  BuildInProgress --> Idle: NotifyBuild(details,Canceled)

  BuildSucceeded --> Idle: auto
  BuildFailed --> Idle: auto
  TimedOut --> Idle: auto

Notes

• Correlation: only events with the same TStateDetails affect the in‑flight cycle; others are ignored.
• Threading: events may be raised from a thread pool callback; marshal to UI if needed.
• Reset semantics: Reset() clears any active correlated StateDetails so Idle states are emitted without an active payload.
• Out-of-order completion: reporting CompletedSuccess/CompletedFailure is supported even if Began wasn't observed; the cycle transitions to the corresponding outcome and then Idle.