Trait biodivine_sketchbook::app::state::StackSession

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pub trait StackSession: SessionState {
    // Required methods
    fn process_message(
        &mut self,
        message: &SessionMessage,
    ) -> Result<(Option<SessionMessage>, Option<StateChange>), DynError>;
    fn id(&self) -> &str;
    fn undo_stack(&self) -> &UndoStack;
    fn undo_stack_mut(&mut self) -> &mut UndoStack;

    // Provided methods
    fn perform_action(
        &mut self,
        action: &UserAction,
    ) -> Result<StateChange, DynError> { ... }
    fn perform_categorized_action(
        &mut self,
        action: &UserAction,
        ignore_stack: bool,
    ) -> Result<StateChange, DynError> { ... }
    fn append_stack_updates(&self, state_changes: &mut Vec<Event>) { ... }
}

Expand description

A Session with a UndoStack with events.

Sessions perform user actions, or communicate with different sessions via messages.

Required Methods§

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fn process_message( &mut self, message: &SessionMessage, ) -> Result<(Option<SessionMessage>, Option<StateChange>), DynError>

Process a message sent to this session state object.

Depending on the message, an optional “response” SessionMessage might be returned. This will be sent to the sender of the original message. Similarly, if the processing of the message caused some changes to the state, an optional “refresh” SessionMessage should be returned to then update the frontend.

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fn id(&self) -> &str

Returns the string identifier of this particular session. Each session identifier must be unique within the application.

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fn undo_stack(&self) -> &UndoStack

Returns an immutable reference to session’s undo stack.

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fn undo_stack_mut(&mut self) -> &mut UndoStack

Returns a mutable reference to session’s undo stack.

Provided Methods§

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fn perform_action( &mut self, action: &UserAction, ) -> Result<StateChange, DynError>

Perform a user action on this session state object. This usually involves propagating the events to the internal SessionState objects and collecting the results into a single StateChange entry.

In this top-level method, we explicitly test for undo-stack actions. Once that is done, the processing continues via StackSession::perform_categorized_action.

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fn perform_categorized_action( &mut self, action: &UserAction, ignore_stack: bool, ) -> Result<StateChange, DynError>

Perform a user action on this session state object, with additional information whether the action should bypass the undo-redo stack.

This method assumes the action was already categorized into one of undo (stack should be bypassed) or regular (goes to the undo stack). If you want to run the full process including categorizing the action, use StackSession::perform_action.

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