Struct CascadeUsagesResolver 

pub struct CascadeUsagesResolver<T, L>
where
    T: LinkReference,
    L: Doublets<T>,
{ /* private fields */ }

Deletes everything that references a link before deleting the link itself.

Port of C# LinksCascadeUsagesResolver together with ILinksExtensions.DeleteAllUsages.

Deviation from C#

C# recurses through the facade and keeps no record of what it has already visited, so a reference cycle (a → b → a) makes it recurse until the stack overflows. This port threads a visited set through the cascade, so cyclic graphs terminate. The price is that the nested deletions run from this layer inwards rather than from the top of the stack; place this decorator above the layers whose behaviour the cascade must observe.

Implementations

impl<T, L> CascadeUsagesResolver<T, L>

where T: LinkReference, L: Doublets<T>,

pub const fn new(links: L) -> CascadeUsagesResolver<T, L>

Wraps links in a CascadeUsagesResolver.

pub const fn inner(&self) -> &L

Returns a shared reference to the wrapped store.

pub const fn inner_mut(&mut self) -> &mut L

Returns a mutable reference to the wrapped store.

pub fn into_inner(self) -> L

Unwraps the decorator and returns the wrapped store.

Trait Implementations

impl<T, L> Debug for CascadeUsagesResolver<T, L>

where T: LinkReference, L: Doublets<T> + Debug,

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl<T, L> Doublets<T> for CascadeUsagesResolver<T, L>

where T: LinkReference, L: Doublets<T>,

fn get_link(&self, index: T) -> Option<Link<T>>

Returns the link at index, or None if it does not exist.

fn count_by(&self, query: impl ToQuery<T>) -> T

where Self: Sized,

Counts links matching query.

fn count(&self) -> T

where Self: Sized,

Returns the total number of links in the store.

fn create_by_with<F>( &mut self, query: impl ToQuery<T>, handler: F, ) -> Result<Flow, Error<T>>

where F: FnMut(Link<T>, Link<T>) -> Flow, Self: Sized,

Creates a link matching query, calling handler on each created link.

fn create_by(&mut self, query: impl ToQuery<T>) -> Result<T, Error<T>>

where Self: Sized,

Creates a link matching query and returns its index.

fn create_with<F>(&mut self, handler: F) -> Result<Flow, Error<T>>

where F: FnMut(Link<T>, Link<T>) -> Flow, Self: Sized,

Creates a new link and calls handler with the before/after states.

fn create(&mut self) -> Result<T, Error<T>>

where Self: Sized,

Creates a new uninitialized link and returns its index.

fn each_by<F>(&self, query: impl ToQuery<T>, handler: F) -> Flow

where F: FnMut(Link<T>) -> Flow, Self: Sized,

Iterates over links matching query, calling handler for each.

fn each<F>(&self, handler: F) -> Flow

where F: FnMut(Link<T>) -> Flow, Self: Sized,

Iterates over all links in the store, calling handler for each.

fn update_by_with<H>( &mut self, query: impl ToQuery<T>, change: impl ToQuery<T>, handler: H, ) -> Result<Flow, Error<T>>

where H: FnMut(Link<T>, Link<T>) -> Flow, Self: Sized,

Updates links matching query to change, calling handler with before/after.

fn update_by( &mut self, query: impl ToQuery<T>, change: impl ToQuery<T>, ) -> Result<T, Error<T>>

where Self: Sized,

Updates links matching query to change and returns the updated link’s index.

fn update_with<F>( &mut self, index: T, source: T, target: T, handler: F, ) -> Result<Flow, Error<T>>

where F: FnMut(Link<T>, Link<T>) -> Flow, Self: Sized,

Updates the link at index to (index, source, target), calling handler.

fn update(&mut self, index: T, source: T, target: T) -> Result<T, Error<T>>

where Self: Sized,

Updates the link at index to (index, source, target) and returns the index.

fn delete_by_with<F>( &mut self, query: impl ToQuery<T>, handler: F, ) -> Result<Flow, Error<T>>

where F: FnMut(Link<T>, Link<T>) -> Flow, Self: Sized,

Deletes links matching query, calling handler with before/after states.

fn delete_by(&mut self, query: impl ToQuery<T>) -> Result<T, Error<T>>

where Self: Sized,

Deletes links matching query and returns the deleted link’s index.

fn delete_with<F>(&mut self, index: T, handler: F) -> Result<Flow, Error<T>>

where F: FnMut(Link<T>, Link<T>) -> Flow, Self: Sized,

Deletes the link at index, calling handler with before/after states.

fn delete(&mut self, index: T) -> Result<T, Error<T>>

where Self: Sized,

Deletes the link at index and returns its former index.

fn try_get_link(&self, index: T) -> Result<Link<T>, Error<T>>

Returns the link at index, or Err(Error::NotExists) if it does not exist.

fn delete_all(&mut self) -> Result<(), Error<T>>

where Self: Sized,

Deletes all links in the store.

fn delete_query_with<F>( &mut self, query: impl ToQuery<T>, handler: F, ) -> Result<(), Error<T>>

where F: FnMut(Link<T>, Link<T>) -> Flow, Self: Sized,

Deletes all links matching query, calling handler for each deletion.

fn delete_usages_with<F>( &mut self, index: T, handler: F, ) -> Result<(), Error<T>>

where F: FnMut(Link<T>, Link<T>) -> Flow, Self: Sized,

Deletes all links that use index as a source or target, calling handler for each.

fn delete_usages(&mut self, index: T) -> Result<(), Error<T>>

where Self: Sized,

Deletes all links that use index as a source or target.

fn create_point(&mut self) -> Result<T, Error<T>>

where Self: Sized,

Creates a self-referential point link and returns its index.

fn create_link_with<F>( &mut self, source: T, target: T, handler: F, ) -> Result<Flow, Error<T>>

where F: FnMut(Link<T>, Link<T>) -> Flow, Self: Sized,

Creates a link from source to target, calling handler with before/after states.

fn create_link(&mut self, source: T, target: T) -> Result<T, Error<T>>

where Self: Sized,

Creates a link from source to target and returns its index.

fn found(&self, query: impl ToQuery<T>) -> bool

where Self: Sized,

Returns true if at least one link matches query.

fn find(&self, query: impl ToQuery<T>) -> Option<Link<T>>

where Self: Sized,

Returns the first link matching query, or None.

fn search(&self, source: T, target: T) -> Option<T>

where Self: Sized,

Returns the index of a link with the given source and target, or None.

fn search_or(&self, source: T, target: T, default: T) -> T

where Self: Sized,

👎Deprecated:

use search instead

fn single(&self, query: impl ToQuery<T>) -> Option<Link<T>>

where Self: Sized,

Returns the link matching query only if exactly one link matches; None otherwise.

fn get_or_create(&mut self, source: T, target: T) -> Result<T, Error<T>>

where Self: Sized,

Returns the index of the (source, target) link, creating it if it does not exist.

fn count_usages(&self, index: T) -> Result<T, Error<T>>

where Self: Sized,

Returns the number of other links that reference index as a source or target.

fn usages(&self, index: T) -> Result<Vec<T>, Error<T>>

where Self: Sized,

Returns the indices of all links that reference index as a source or target.

fn exist(&self, link: T) -> bool

where Self: Sized,

Returns true if the link at link exists (internal or external).

fn has_usages(&self, link: T) -> bool

where Self: Sized,

Returns true if any other link references link as a source or target.

fn rebase_with<F>(&mut self, old: T, new: T, handler: F) -> Result<(), Error<T>>

where F: FnMut(Link<T>, Link<T>) -> Flow, Self: Sized,

Re-points all usages of old to new, calling handler for each update.

fn rebase(&mut self, old: T, new: T) -> Result<T, Error<T>>

where Self: Sized,

Re-points all usages of old to new and returns new.

fn rebase_and_delete(&mut self, old: T, new: T) -> Result<T, Error<T>>

where Self: Sized,

Re-points all usages of old to new, then deletes old. Returns new.

impl<T, L> Links<T> for CascadeUsagesResolver<T, L>

where T: LinkReference, L: Doublets<T>,

fn constants(&self) -> &LinksConstants<T>

Returns the store’s LinksConstants (any/null/range values).

fn count_links(&self, query: &[T]) -> T

Counts links that match query.

fn each_links( &self, query: &[T], handler: &mut dyn FnMut(Link<T>) -> Flow, ) -> Flow

Iterates over links matching query, calling handler for each.

fn create_links( &mut self, query: &[T], handler: &mut dyn FnMut(Link<T>, Link<T>) -> Flow, ) -> Result<Flow, Error<T>>

Creates one or more links matching query and reports each creation via handler.

fn update_links( &mut self, query: &[T], change: &[T], handler: &mut dyn FnMut(Link<T>, Link<T>) -> Flow, ) -> Result<Flow, Error<T>>

Updates links matching query to the new values in change, reporting via handler.

fn delete_links( &mut self, query: &[T], handler: &mut dyn FnMut(Link<T>, Link<T>) -> Flow, ) -> Result<Flow, Error<T>>

Deletes links matching query and reports each deletion via handler.