Struct Dict 

pub struct Dict { /* private fields */ }

A refcounted per-document string interner.

Never construct directly with Dict { ... } — use Dict::new_refcounted which guarantees the heap allocation and initial refcount of 1. Internally not Send/Sync despite the atomic refcount: the RefCell guarding the table is single- threaded. C-ABI consumers (libxml2) are GIL-protected on the Python side and single-thread the dict accordingly.

Implementations

impl Dict

pub fn new_refcounted() -> *mut Dict

Allocate a fresh dict on the heap. Refcount starts at 1 (the caller’s reference). Returns a raw pointer; callers must eventually balance with Dict::release.

pub unsafe fn new_sub(parent: *mut Dict) -> *mut Dict

Allocate a sub-dictionary chained to parent (libxml2 xmlDictCreateSub). The sub-dict shares the parent’s interned strings — see the parent field — and takes one reference to it, released when the sub-dict is freed. A NULL parent is equivalent to new_refcounted.

Safety

parent must be NULL or a live Dict* on which the caller can take a reference.

pub fn retain_arena(&self, arena: Arc<Bump>)

Retain arena (an origin document’s node arena) so a node moved out of it — whose name re-interned into this dict during a cross-thread graft — outlives a drop of its origin document. Deduped by pointer, so repeated grafts from one source arena keep a single entry. The caller guarantees arena is not the destination’s own (a same-arena move needs no retention).

pub fn add_ref(&self)

Increment the refcount. Use when copying a *mut Dict to a new owner. Cheap atomic op.

pub unsafe fn release(ptr: *mut Dict) -> bool

Decrement the refcount. When the last reference goes away, drops every interned string and the dict itself. Returns true if this call was the one that freed.

Safety

ptr must be a non-null pointer previously returned by Dict::new_refcounted, and the caller must own one reference (i.e. exactly one outstanding add_ref not yet paired with a release).

pub fn refcount(&self) -> usize

Current refcount. For tests + debugging; not load-bearing.

pub fn intern(&self, input: &[u8]) -> *const u8

Look up input, inserting if absent. Returns the canonical NUL-terminated pointer.

pub fn intern_str(&self, s: &str) -> *const u8

&str-keyed convenience over Self::intern.

pub fn lookup(&self, input: &[u8]) -> *const u8

Non-allocating lookup. Returns the canonical pointer on hit, NULL on miss.

pub fn owns(&self, ptr: *const u8) -> bool

Does ptr originate from this dict or any ancestor? libxml2’s xmlDictOwns walks the sub-dict chain, so a string interned in the parent is “owned” when probed through a child.

pub fn len(&self) -> usize

Number of distinct strings interned.

pub fn is_empty(&self) -> bool