Enum LazyLayoutKey 

pub enum LazyLayoutKey {
    User(u64),
    Index(usize),
}

Key type for lazy list items.

Separates user-provided keys from default index-based keys to prevent collisions. This matches JC’s getDefaultLazyLayoutKey() pattern where a wrapper type (DefaultLazyKey) ensures default keys never collide with user-provided keys.

JC Reference

• LazyLayoutIntervalContent.getKey() returns content.key?.invoke(localIndex) ?: getDefaultLazyLayoutKey(index)
• Lazy.android.kt defines DefaultLazyKey(index) as a wrapper data class

Variants

User(u64)

User-provided key (from scope.item(key: Some(k), ...) or scope.items(key: Some(|i| ...), ...))

Index(usize)

Default key based on global index. Cannot collide with User keys due to enum separation.

Implementations

impl LazyLayoutKey

pub fn to_slot_id(self) -> u64

Converts to u64 for slot ID usage with guaranteed non-overlapping ranges.

Encoding

Uses high 2 bits of the 64-bit slot ID as a type tag:

• User keys: 0b00 tag + 62-bit value (range: 0x0000… - 0x3FFF…)
• Index keys: 0b01 tag + 62-bit value (range: 0x4000… - 0x7FFF…)

⚠️ Large Key Handling

Values larger than 62 bits are mixed down to 62 bits. This avoids panics for extreme indices (e.g. usize::MAX) but introduces a small chance of collisions for out-of-range keys. Prefer keys that fit in 62 bits when you need guaranteed collision-free IDs.

Cross-Platform Safety

The slot ID is always u64 regardless of target platform.

pub fn is_user_key(self) -> bool

Returns true if this is a user-provided key.

pub fn is_index_key(self) -> bool

Returns true if this is a default index-based key.

Trait Implementations

impl Clone for LazyLayoutKey

fn clone(&self) -> LazyLayoutKey

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for LazyLayoutKey

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Hash for LazyLayoutKey

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for LazyLayoutKey

fn eq(&self, other: &LazyLayoutKey) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Copy for LazyLayoutKey

impl Eq for LazyLayoutKey

impl StructuralPartialEq for LazyLayoutKey