pub struct ForkTree<H, N, V> { /* private fields */ }Expand description
A tree data structure that stores several nodes across multiple branches.
Top-level branches are called roots. The tree has functionality for finalizing nodes, which means that node is traversed, and all competing branches are pruned. It also guarantees that nodes in the tree are finalized in order. Each node is uniquely identified by its hash but can be ordered by its number. In order to build the tree an external function must be provided when interacting with the tree to establish a node’s ancestry.
Implementations§
source§impl<H, N, V> ForkTree<H, N, V>where
H: PartialEq,
N: Ord,
impl<H, N, V> ForkTree<H, N, V>where H: PartialEq, N: Ord,
sourcepub fn rebalance(&mut self)
pub fn rebalance(&mut self)
Rebalance the tree.
For each tree level sort child nodes by max branch depth (decreasing).
Most operations in the tree are performed with depth-first search starting from the leftmost node at every level, since this tree is meant to be used in a blockchain context, a good heuristic is that the node we’ll be looking for at any point will likely be in one of the deepest chains (i.e. the longest ones).
sourcepub fn import<F, E>(
&mut self,
hash: H,
number: N,
data: V,
is_descendent_of: &F
) -> Result<bool, Error<E>>where
E: Error,
F: Fn(&H, &H) -> Result<bool, E>,
pub fn import<F, E>( &mut self, hash: H, number: N, data: V, is_descendent_of: &F ) -> Result<bool, Error<E>>where E: Error, F: Fn(&H, &H) -> Result<bool, E>,
Import a new node into the tree.
The given function is_descendent_of should return true if the second
hash (target) is a descendent of the first hash (base).
This method assumes that nodes in the same branch are imported in order.
Returns true if the imported node is a root.
sourcepub fn roots(&self) -> impl Iterator<Item = (&H, &N, &V)>
pub fn roots(&self) -> impl Iterator<Item = (&H, &N, &V)>
Iterates over the existing roots in the tree.
sourcepub fn iter(&self) -> impl Iterator<Item = (&H, &N, &V)>
pub fn iter(&self) -> impl Iterator<Item = (&H, &N, &V)>
Iterates the nodes in the tree in pre-order.
sourcepub fn map<VT, F>(self, f: &mut F) -> ForkTree<H, N, VT>where
F: FnMut(&H, &N, V) -> VT,
pub fn map<VT, F>(self, f: &mut F) -> ForkTree<H, N, VT>where F: FnMut(&H, &N, V) -> VT,
Map fork tree into values of new types.
Tree traversal technique (e.g. BFS vs DFS) is left as not specified and may be subject to change in the future. In other words, your predicates should not rely on the observed traversal technique currently in use.
sourcepub fn find_node_where<F, E, P>(
&self,
hash: &H,
number: &N,
is_descendent_of: &F,
predicate: &P
) -> Result<Option<&Node<H, N, V>>, Error<E>>where
E: Error,
F: Fn(&H, &H) -> Result<bool, E>,
P: Fn(&V) -> bool,
pub fn find_node_where<F, E, P>( &self, hash: &H, number: &N, is_descendent_of: &F, predicate: &P ) -> Result<Option<&Node<H, N, V>>, Error<E>>where E: Error, F: Fn(&H, &H) -> Result<bool, E>, P: Fn(&V) -> bool,
Find a node in the tree that is the deepest ancestor of the given block hash and which passes the given predicate.
The given function is_descendent_of should return true if the
second hash (target) is a descendent of the first hash (base).
sourcepub fn find_node_where_mut<F, E, P>(
&mut self,
hash: &H,
number: &N,
is_descendent_of: &F,
predicate: &P
) -> Result<Option<&mut Node<H, N, V>>, Error<E>>where
E: Error,
F: Fn(&H, &H) -> Result<bool, E>,
P: Fn(&V) -> bool,
pub fn find_node_where_mut<F, E, P>( &mut self, hash: &H, number: &N, is_descendent_of: &F, predicate: &P ) -> Result<Option<&mut Node<H, N, V>>, Error<E>>where E: Error, F: Fn(&H, &H) -> Result<bool, E>, P: Fn(&V) -> bool,
Same as find_node_where, but returns mutable reference.
sourcepub fn find_node_index_where<F, E, P>(
&self,
hash: &H,
number: &N,
is_descendent_of: &F,
predicate: &P
) -> Result<Option<Vec<usize>>, Error<E>>where
E: Error,
F: Fn(&H, &H) -> Result<bool, E>,
P: Fn(&V) -> bool,
pub fn find_node_index_where<F, E, P>( &self, hash: &H, number: &N, is_descendent_of: &F, predicate: &P ) -> Result<Option<Vec<usize>>, Error<E>>where E: Error, F: Fn(&H, &H) -> Result<bool, E>, P: Fn(&V) -> bool,
Same as find_node_where, but returns indices.
The returned indices represent the full path to reach the matching node starting from one of the roots, i.e. the earliest index in the traverse path goes first, and the final index in the traverse path goes last.
If a node is found that matches the predicate the returned path should always
contain at least one index, otherwise None is returned.
sourcepub fn prune<F, E, P>(
&mut self,
hash: &H,
number: &N,
is_descendent_of: &F,
predicate: &P
) -> Result<impl Iterator<Item = (H, N, V)>, Error<E>>where
E: Error,
F: Fn(&H, &H) -> Result<bool, E>,
P: Fn(&V) -> bool,
pub fn prune<F, E, P>( &mut self, hash: &H, number: &N, is_descendent_of: &F, predicate: &P ) -> Result<impl Iterator<Item = (H, N, V)>, Error<E>>where E: Error, F: Fn(&H, &H) -> Result<bool, E>, P: Fn(&V) -> bool,
Prune the tree, removing all non-canonical nodes.
We find the node in the tree that is the deepest ancestor of the given hash and that passes the given predicate. If such a node exists, we re-root the tree to this node. Otherwise the tree remains unchanged.
The given function is_descendent_of should return true if the second
hash (target) is a descendent of the first hash (base).
Returns all pruned nodes data.
sourcepub fn finalize_root(&mut self, hash: &H) -> Option<V>
pub fn finalize_root(&mut self, hash: &H) -> Option<V>
Finalize a root in the tree and return it, return None in case no root
with the given hash exists. All other roots are pruned, and the children
of the finalized node become the new roots.
sourcepub fn finalize<F, E>(
&mut self,
hash: &H,
number: N,
is_descendent_of: &F
) -> Result<FinalizationResult<V>, Error<E>>where
E: Error,
F: Fn(&H, &H) -> Result<bool, E>,
pub fn finalize<F, E>( &mut self, hash: &H, number: N, is_descendent_of: &F ) -> Result<FinalizationResult<V>, Error<E>>where E: Error, F: Fn(&H, &H) -> Result<bool, E>,
Finalize a node in the tree. This method will make sure that the node
being finalized is either an existing root (and return its data), or a
node from a competing branch (not in the tree), tree pruning is done
accordingly. The given function is_descendent_of should return true
if the second hash (target) is a descendent of the first hash (base).
sourcepub fn finalize_with_ancestors<F, E>(
&mut self,
hash: &H,
number: N,
is_descendent_of: &F
) -> Result<FinalizationResult<V>, Error<E>>where
E: Error,
F: Fn(&H, &H) -> Result<bool, E>,
pub fn finalize_with_ancestors<F, E>( &mut self, hash: &H, number: N, is_descendent_of: &F ) -> Result<FinalizationResult<V>, Error<E>>where E: Error, F: Fn(&H, &H) -> Result<bool, E>,
Finalize a node in the tree and all its ancestors. The given function
is_descendent_of should return true if the second hash (target) is
sourcepub fn finalizes_any_with_descendent_if<F, P, E>(
&self,
hash: &H,
number: N,
is_descendent_of: &F,
predicate: P
) -> Result<Option<bool>, Error<E>>where
E: Error,
F: Fn(&H, &H) -> Result<bool, E>,
P: Fn(&V) -> bool,
pub fn finalizes_any_with_descendent_if<F, P, E>( &self, hash: &H, number: N, is_descendent_of: &F, predicate: P ) -> Result<Option<bool>, Error<E>>where E: Error, F: Fn(&H, &H) -> Result<bool, E>, P: Fn(&V) -> bool,
Checks if any node in the tree is finalized by either finalizing the
node itself or a node’s descendent that’s not in the tree, guaranteeing
that the node being finalized isn’t a descendent of (or equal to) any of
the node’s children. Returns Some(true) if the node being finalized is
a root, Some(false) if the node being finalized is not a root, and
None if no node in the tree is finalized. The given predicate is
checked on the prospective finalized root and must pass for finalization
to occur. The given function is_descendent_of should return true if
the second hash (target) is a descendent of the first hash (base).
sourcepub fn finalize_with_descendent_if<F, P, E>(
&mut self,
hash: &H,
number: N,
is_descendent_of: &F,
predicate: P
) -> Result<FinalizationResult<V>, Error<E>>where
E: Error,
F: Fn(&H, &H) -> Result<bool, E>,
P: Fn(&V) -> bool,
pub fn finalize_with_descendent_if<F, P, E>( &mut self, hash: &H, number: N, is_descendent_of: &F, predicate: P ) -> Result<FinalizationResult<V>, Error<E>>where E: Error, F: Fn(&H, &H) -> Result<bool, E>, P: Fn(&V) -> bool,
Finalize a root in the tree by either finalizing the node itself or a
node’s descendent that’s not in the tree, guaranteeing that the node
being finalized isn’t a descendent of (or equal to) any of the root’s
children. The given predicate is checked on the prospective finalized
root and must pass for finalization to occur. The given function
is_descendent_of should return true if the second hash (target) is a
descendent of the first hash (base).
sourcepub fn drain_filter<F>(&mut self, filter: F) -> impl Iterator<Item = (H, N, V)>where
F: Fn(&H, &N, &V) -> FilterAction,
pub fn drain_filter<F>(&mut self, filter: F) -> impl Iterator<Item = (H, N, V)>where F: Fn(&H, &N, &V) -> FilterAction,
Remove from the tree some nodes (and their subtrees) using a filter predicate.
The filter is called over tree nodes and returns a filter action:
Removeif the node and its subtree should be removed;KeepNodeif we should maintain the node and keep processing the tree.KeepTreeif we should maintain the node and its entire subtree.
An iterator over all the pruned nodes is returned.