# Struct rustc_data_structures::graph::iterate::TriColorDepthFirstSearch

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    pub struct TriColorDepthFirstSearch<'graph, G>where
        G: ?Sized + DirectedGraph + WithNumNodes + WithSuccessors,{
        graph: &'graph G,
        stack: Vec<Event<G::Node>>,
        visited: BitSet<G::Node>,
        settled: BitSet<G::Node>,
    }

Expand description

A depth-first search that also tracks when all successors of a node have been examined.

This is based on the DFS described in Introduction to Algorithms (1st ed.), hereby referred to as CLR. However, we use the terminology in `NodeStatus` above instead of “discovered”/“finished” or “white”/“grey”/“black”. Each node begins the search with no status, becomes `Visited` when it is first examined by the DFS and is `Settled` when all nodes reachable from it have been examined. This allows us to differentiate between “tree”, “back” and “forward” edges (see `TriColorVisitor::node_examined`).

Unlike the pseudocode in CLR, this implementation is iterative and does not use timestamps. We accomplish this by storing `Event`s on the stack that result in a (possible) state change for each node. A `Visited` event signifies that we should examine this node if it has not yet been `Visited` or `Settled`. When a node is examined for the first time, we mark it as `Visited` and push a `Settled` event for it on stack followed by `Visited` events for all of its predecessors, scheduling them for examination. Multiple `Visited` events for a single node may exist on the stack simultaneously if a node has multiple predecessors, but only one `Settled` event will ever be created for each node. After all `Visited` events for a node’s successors have been popped off the stack (as well as any new events triggered by visiting those successors), we will pop off that node’s `Settled` event.

## Fields§

§`graph: &'graph G`§`stack: Vec<Event<G::Node>>`§`visited: BitSet<G::Node>`§`settled: BitSet<G::Node>`

## Implementations§

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### impl<'graph, G> TriColorDepthFirstSearch<'graph, G>
where G: ?Sized + DirectedGraph + WithNumNodes + WithSuccessors,

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#### pub fn new(graph: &'graph G) -> Self

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#### pub fn run_from<V>(self, root: G::Node, visitor: &mut V) -> Option<V::BreakVal>
where V: TriColorVisitor<G>,

Performs a depth-first search, starting from the given `root`.

This won’t visit nodes that are not reachable from `root`.

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### impl<G> TriColorDepthFirstSearch<'_, G>
where G: ?Sized + DirectedGraph + WithNumNodes + WithSuccessors + WithStartNode,

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#### pub fn run_from_start<V>(self, visitor: &mut V) -> Option<V::BreakVal>
where V: TriColorVisitor<G>,

Performs a depth-first search, starting from `G::start_node()`.

This won’t visit nodes that are not reachable from the start node.

## Auto Trait Implementations§

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### impl<'graph, G: ?Sized> DynSend for TriColorDepthFirstSearch<'graph, G>
where G: DynSync, <G as DirectedGraph>::Node: DynSend,

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### impl<'graph, G: ?Sized> DynSync for TriColorDepthFirstSearch<'graph, G>
where G: DynSync, <G as DirectedGraph>::Node: DynSync,

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### impl<'graph, G: ?Sized> Freeze for TriColorDepthFirstSearch<'graph, G>

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### impl<'graph, G: ?Sized> RefUnwindSafe for TriColorDepthFirstSearch<'graph, G>
where G: RefUnwindSafe, <G as DirectedGraph>::Node: RefUnwindSafe,

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### impl<'graph, G: ?Sized> Send for TriColorDepthFirstSearch<'graph, G>
where G: Sync, <G as DirectedGraph>::Node: Send,

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### impl<'graph, G: ?Sized> Sync for TriColorDepthFirstSearch<'graph, G>
where G: Sync, <G as DirectedGraph>::Node: Sync,

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### impl<'graph, G: ?Sized> Unpin for TriColorDepthFirstSearch<'graph, G>
where <G as DirectedGraph>::Node: Unpin,

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### impl<'graph, G: ?Sized> UnwindSafe for TriColorDepthFirstSearch<'graph, G>
where G: RefUnwindSafe, <G as DirectedGraph>::Node: UnwindSafe,

## Blanket Implementations§

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### impl<T> Aligned for T

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#### const ALIGN: Alignment = const ALIGN: Alignment = Alignment::of::<Self>();

Alignment of `Self`.
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### impl<T> Any for T
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#### fn type_id(&self) -> TypeId

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where T: ?Sized,

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where T: ?Sized,

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#### fn borrow_mut(&mut self) -> &mut T

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#### fn from(t: T) -> T

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#### fn instrument(self, span: Span) -> Instrumented<Self>

Instruments this type with the provided `Span`, returning an `Instrumented` wrapper. Read more
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### impl<T, U> Into<U> for T
where U: From<T>,

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#### fn into(self) -> U

Calls `U::from(self)`.

That is, this conversion is whatever the implementation of `From<T> for U` chooses to do.

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### impl<T> Pointable for T

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#### const ALIGN: usize = _

The alignment of pointer.
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#### type Init = T

The type for initializers.
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#### unsafe fn init(init: <T as Pointable>::Init) -> usize

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#### unsafe fn drop(ptr: usize)

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### impl<T, U> TryFrom<U> for T
where U: Into<T>,

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#### type Error = Infallible

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where U: TryFrom<T>,

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#### type Error = <U as TryFrom<T>>::Error

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### impl<T> WithSubscriber for T

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#### fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self>
where S: Into<Dispatch>,

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## Layout§

Note: Unable to compute type layout, possibly due to this type having generic parameters. Layout can only be computed for concrete, fully-instantiated types.