Struct DerivationTree 

pub struct DerivationTree<const N: usize = DEFAULT_CAP_TABLE_CAPACITY> { /* private fields */ }

Derivation tree for tracking parent-child capability relationships.

Fixed-size array indexed by slot index. No heap allocation.

Implementations

impl<const N: usize> DerivationTree<N>

pub const fn new() -> Self

Creates a new empty derivation tree.

pub const fn len(&self) -> usize

Returns the number of active nodes.

pub const fn is_empty(&self) -> bool

Returns true if the tree has no active nodes.

pub fn add_root(&mut self, index: u32, epoch: u64) -> CapResult<()>

Registers a root capability in the tree.

Errors

Returns CapError::TreeFull if the index is out of bounds.

pub fn add_child( &mut self, parent_index: u32, child_index: u32, depth: u8, epoch: u64, ) -> CapResult<()>

Registers a derived capability in the tree, linking it to its parent.

Errors

Returns CapError::TreeFull if either index is out of bounds. Returns CapError::Revoked if the parent node has been revoked.

pub fn revoke(&mut self, index: u32) -> CapResult<usize>

Revokes a node and all its descendants. Returns the count of revoked nodes.

Errors

Returns CapError::InvalidHandle if the index is out of bounds. Returns CapError::Revoked if the node has already been revoked.

pub fn depth(&self, index: u32) -> CapResult<u8>

Returns the depth of the node at the given index.

Errors

Returns CapError::InvalidHandle if the index is invalid or the node is revoked.

pub fn is_valid(&self, index: u32) -> bool

Returns true if the node at the given index is valid.

pub fn get(&self, index: u32) -> Option<&DerivationNode>

Returns a reference to a node by index.

pub fn collect_subtree(&self, index: u32) -> [u32; N]

Collect all valid indices in the subtree rooted at index.

Returns a fixed-size array of indices (up to N). This is used by revocation to synchronize the capability table.

Uses an iterative stack to avoid stack overflow on wide trees.

pub fn find_parent(&self, child_index: u32) -> Option<u32>

Find the parent of a given node.

Uses the cached parent_index field for O(1) lookup. Falls back to O(N) scan if the cached index is stale (should not happen in normal operation).

Returns None for root nodes or if the parent is not found.

Trait Implementations

impl<const N: usize> Default for DerivationTree<N>

fn default() -> Self

Returns the “default value” for a type.