Crate zng_app

App process implementation.

Widget Instantiation

See enable_widget_macros! if you want to instantiate widgets without depending on the zng crate.

Crate

This crate is part of the zng project.

Cargo Features

This crate provides 12 feature flags, 3 enabled by default.

"debug_default"

Enable the "dyn_*" and "inspector" features in debug builds.

Enabled by default.

"dyn_node"

Use dynamic dispatch at the node level by placing each property node in a BoxedUiNode and enabling UiNode::cfg_boxed.

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

"inspector"

Instrument each widget instance to retain build information.

"dyn_app_extension"

Use dynamic dispatch at the app-extension level.

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

"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.

"test_util"

Like cfg(test) but also visible in docs and integration tests.

"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.

Not enabled by default, but enabled by feature="test_util".

"trace_widget"

Instrument every widget outer-most node to trace UI methods.

"trace_wgt_item"

Instrument every property and intrinsic node to trace UI methods.

Note that this can cause very large trace files and bad performance.

"crash_handler"

Allow app-process crash handler.

Note that crash_handler::init(_) must be called to enable.

Enabled by default.

"ipc"

Enables IPC tasks and pre-build views and connecting to views running in another process.

Enabled by default.

"deadlock_detection"

Spawns a thread on app creation that checks and prints parking_lot deadlocks.

Not enabled by default, but enabled by feature="test_util".

Modules

• access
  Accessibility/automation events.
• crash_handler
  App-process crash handler.
• event
  App event and commands API.
• handler
  Handler types and macros.
• render
  Frame render and metadata API.
• shortcut
  Key combination types.
• third_party
  Third party licenses service and types.
• timer
  App timers, deadlines and timeouts.
• update
  App updates API.
• view_process
  View process connection and other types.
• widget
  Widget, UI node API.
• window
  Window context API.

Macros

• about_app_from_crate
  Generate an AboutApp value from the crate’s metadata.
• app_hn
  Declare a mutable clone-move app event handler.
• app_hn_once
  Declare a clone-move app event handler that is only called once.
• async_app_hn
  Declare an async clone-move app event handler.
• async_app_hn_once
  Declare an async clone-move app event handler that is only called once.
• async_hn
  Declare an async clone-move event handler.
• async_hn_once
  Declare an async clone-move event handler that is only called once.
• command
  Declares new Command static items.
• enable_widget_macros
  Enable widget instantiation in crates that can’t depend on the zng crate.
• event_args
  Declares new EventArgs types.
• event_macro
  Declares new Event<A> static items.
• hn
  Declare a mutable clone-move event handler.
• hn_once
  Declare a clone-move event handler that is only called once.
• property_args
  New Box<PropertyArgs> box from a property and value.
• property_id
  New PropertyId that represents the type and name.
• property_info
  New PropertyInfo from property path.
• property_input_types
  Gets the strong input storage types from a property path.
• shortcut_macro
  Creates a Shortcut.
• source_location
  New SourceLocation that represents the location you call this macro.
• ui_vec
  Creates an UiNodeVec containing the arguments.
• widget_impl
  Implement a property on the widget to strongly associate it with the widget.
• widget_set
  Sets properties and when condition on a widget builder.
• widget_type
  Gets the WidgetType info of a widget.

Structs

• APP
  Start and manage an app process.
• AboutApp
  Display info about the current app.
• AppEventSender
  A sender that can awake apps and insert events into the main loop.
• AppExtReceiver
  Represents a channel receiver in an app extension.
• AppExtSender
  Represents a channel sender that causes an extensions update for each value transferred.
• AppExtSenderDisconnected
  Error when the app connected to a sender/receiver channel has disconnected.
• AppExtended
  Application builder.
• AppExtensionInfo
  Info about an app-extension.
• AppExtensionsInfo
  List of app-extensions that are part of an app.
• DInstant
  Duration elapsed since an epoch.
• Deadline
  Represents a timeout instant.
• ExitCancelled
  Cancellation message of an exit request.
• ExitRequestedArgs
  Arguments for EXIT_REQUESTED_EVENT.
• HeadlessApp
  A headless app controller.
• INSTANT
  Instant service.

Enums

• AppControlFlow
  Desired next step of app main loop.
• InstantMode
  Defines how the INSTANT.now value updates in the app.

Statics

• EXIT_CMD
  Represents the app process exit request.
• EXIT_REQUESTED_EVENT
  Cancellable event raised when app process exit is requested.

Traits

• AppEventObserver
  Observer for HeadlessApp::update_observed.
• AppExtension
  An app extension.

Functions

• print_tracing
  Print tracing events if a subscriber is not already set.
• test_log
  Modifies the print_tracing subscriber to panic for error logs in the current app.