```
struct SccsConstruction<'c, G, S, A, F>{
graph: &'c G,
node_states: IndexVec<G::Node, NodeState<G::Node, S, A>>,
node_stack: Vec<G::Node>,
successors_stack: Vec<S>,
duplicate_set: FxHashSet<S>,
scc_data: SccData<S, A>,
to_annotation: F,
}
```

## Fields§

§`graph: &'c G`

§`node_states: IndexVec<G::Node, NodeState<G::Node, S, A>>`

The state of each node; used during walk to record the stack and after walk to record what cycle each node ended up being in.

`node_stack: Vec<G::Node>`

The stack of nodes that we are visiting as part of the DFS.

`successors_stack: Vec<S>`

The stack of successors: as we visit a node, we mark our position in this stack, and when we encounter a successor SCC, we push it on the stack. When we complete an SCC, we can pop everything off the stack that was found along the way.

`duplicate_set: FxHashSet<S>`

A set used to strip duplicates. As we accumulate successors into the successors_stack, we sometimes get duplicate entries. We use this set to remove those – we also keep its storage around between successors to amortize memory allocation costs.

`scc_data: SccData<S, A>`

§`to_annotation: F`

A function that constructs an initial SCC annotation out of a single node.

## Implementations§

source§### impl<'c, G, S, A, F> SccsConstruction<'c, G, S, A, F>

### impl<'c, G, S, A, F> SccsConstruction<'c, G, S, A, F>

source#### fn construct(graph: &'c G, to_annotation: F) -> Sccs<G::Node, S, A>

#### fn construct(graph: &'c G, to_annotation: F) -> Sccs<G::Node, S, A>

Identifies SCCs in the graph `G`

and computes the resulting
DAG. This uses a variant of Tarjan’s
algorithm. The high-level summary of the algorithm
is that we do a depth-first search. Along the way, we keep a
stack of each node whose successors are being visited. We
track the depth of each node on this stack (there is no depth
if the node is not on the stack). When we find that some node
N with depth D can reach some other node N’ with lower depth
D’ (i.e., D’ < D), we know that N, N’, and all nodes in
between them on the stack are part of an SCC.

Additionally, we keep track of a current annotation of the SCC.

#### fn start_walk_from(&mut self, node: G::Node) -> WalkReturn<S, A>

source#### fn inspect_node(&mut self, node: G::Node) -> Option<WalkReturn<S, A>>

#### fn inspect_node(&mut self, node: G::Node) -> Option<WalkReturn<S, A>>

Inspect a node during the DFS. We first examine its current
state – if it is not yet visited (`NotVisited`

), return `None`

so
that the caller might push it onto the stack and start walking its
successors.

If it is already on the DFS stack it will be in the state
`BeingVisited`

. In that case, we have found a cycle and we
return the depth from the stack.

Otherwise, we are looking at a node that has already been
completely visited. We therefore return `WalkReturn::Complete`

with its associated SCC index.

source#### fn find_state(&mut self, node: G::Node) -> NodeState<G::Node, S, A>

#### fn find_state(&mut self, node: G::Node) -> NodeState<G::Node, S, A>

Fetches the state of the node `r`

. If `r`

is recorded as being
in a cycle with some other node `r2`

, then fetches the state
of `r2`

(and updates `r`

to reflect current result). This is
basically the “find” part of a standard union-find algorithm
(with path compression).

source#### fn walk_unvisited_node(&mut self, initial: G::Node) -> WalkReturn<S, A>

#### fn walk_unvisited_node(&mut self, initial: G::Node) -> WalkReturn<S, A>

Walks a node that has never been visited before.

Call this method when `inspect_node`

has returned `None`

. Having the
caller decide avoids mutual recursion between the two methods and allows
us to maintain an allocated stack for nodes on the path between calls.

## Auto Trait Implementations§

### impl<'c, G, S, A, F> DynSend for SccsConstruction<'c, G, S, A, F>

### impl<'c, G, S, A, F> DynSync for SccsConstruction<'c, G, S, A, F>

### impl<'c, G, S, A, F> Freeze for SccsConstruction<'c, G, S, A, F>where
F: Freeze,

### impl<'c, G, S, A, F> RefUnwindSafe for SccsConstruction<'c, G, S, A, F>where
F: RefUnwindSafe,
G: RefUnwindSafe,
<G as DirectedGraph>::Node: RefUnwindSafe,
S: RefUnwindSafe,
A: RefUnwindSafe,

### impl<'c, G, S, A, F> Send for SccsConstruction<'c, G, S, A, F>

### impl<'c, G, S, A, F> Sync for SccsConstruction<'c, G, S, A, F>

### impl<'c, G, S, A, F> Unpin for SccsConstruction<'c, G, S, A, F>

### impl<'c, G, S, A, F> UnwindSafe for SccsConstruction<'c, G, S, A, F>where
F: UnwindSafe,
G: RefUnwindSafe,
<G as DirectedGraph>::Node: UnwindSafe,
S: UnwindSafe,
A: UnwindSafe,

## Blanket Implementations§

source§### impl<T> BorrowMut<T> for Twhere
T: ?Sized,

### impl<T> BorrowMut<T> for Twhere
T: ?Sized,

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

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

source§### impl<T> Instrument for T

### impl<T> Instrument for T

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

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

source§#### fn in_current_span(self) -> Instrumented<Self>

#### fn in_current_span(self) -> Instrumented<Self>

source§### impl<T> IntoEither for T

### impl<T> IntoEither for T

source§#### fn into_either(self, into_left: bool) -> Either<Self, Self>

#### fn into_either(self, into_left: bool) -> Either<Self, Self>

`self`

into a `Left`

variant of `Either<Self, Self>`

if `into_left`

is `true`

.
Converts `self`

into a `Right`

variant of `Either<Self, Self>`

otherwise. Read moresource§#### fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>

#### fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>

`self`

into a `Left`

variant of `Either<Self, Self>`

if `into_left(&self)`

returns `true`

.
Converts `self`

into a `Right`

variant of `Either<Self, Self>`

otherwise. Read moresource§### impl<T> Pointable for T

### impl<T> Pointable for T

source§### impl<T> WithSubscriber for T

### impl<T> WithSubscriber for T

source§#### fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self>

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

source§#### fn with_current_subscriber(self) -> WithDispatch<Self>

#### fn with_current_subscriber(self) -> WithDispatch<Self>

### impl<'a, T> Captures<'a> for Twhere
T: ?Sized,

## 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.