Crate zng_app_context

App execution context.

Crate

This crate is part of the zng project.

Cargo Features

This crate provides 3 feature flags, 1 enabled by default.

"multi_app"

Allows multiple app instances per-process.

This feature allows multiple apps, one app per thread at a time. The LocalContext tracks what app is currently running in each thread and app_local! statics switch to the value of each app depending on the current thread.

"debug_default"

Enable "multi_app" in debug builds.

Enabled by default.

"dyn_closure"

Box closures at opportune places, such as Var::map, reducing the number of monomorphised types.

This speeds-up compilation time at the cost of runtime.

Macros

• app_local
  Declares new app local variable.
• context_local
  Declares new app and context local variable.

Structs

• AppId
  Identifies an app instance.
• AppLocal
  An app local storage.
• AppScope
  Represents an app lifetime, ends the app on drop.
• ContextLocal
  Represents an AppLocal<T> value that can be temporarily overridden in a context.
• ContextValueSet
  Identifies a selection of LocalContext values.
• FullLocalContext
  A local context that can be loaded cheaply.
• LocalContext
  Tracks the current execution context.
• MappedRwLockReadGuardOwned
  Represents a read guard for an Arc<RwLock<T>> that owns a reference to it, mapped from another read guard.
• MappedRwLockWriteGuardOwned
  Represents a write guard for an Arc<RwLock<T>> that owns a reference to it, mapped from another read guard.
• ReadOnlyRwLock
  Read-only wrapper on an Arc<RwLock<T>> contextual value.
• RunOnDrop
  Helper, runs a cleanup action once on drop.
• RwLockReadGuardOwned
  Represents a read guard for an Arc<RwLock<T>> that owns a reference to it.
• RwLockWriteGuardOwned
  Represents a read guard for an Arc<RwLock<T>> that owns a reference to it.
• StaticAppId
  Lazy inited AppId.
• TracingDispatcherContext
  Represents the tracing::dispatcher::get_default dispatcher in a context value set.

Enums

• CaptureFilter
  Defines a LocalContext::capture_filtered filter.

Traits

• ContextLocalKeyProvider
  Provides an identifying key for a context local value.