Enum PropClass 

#[non_exhaustive]
pub enum PropClass {
    Content,
    Placement,
}

What a property describes, for the FB-only fast path.

This is the corollary of invariant 4 the C++ can only state in prose:

property_hash isolates content from placement — every placement or format property moves the hash; FB_ID and IN_FENCE_FD do not. A property misclassified as content would let a real change skip the test.

Here it is data, consumed by PropTag::class’s exhaustive match. A new variant added without a classification does not compile, so the failure the C++ warns about — a property silently treated as content — cannot reach a running system.

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

Content

Changes every frame and does not affect plane compatibility.

Excluded from Layer::property_hash, so a frame that changes only these can reuse the cached plane assignment and skip the redundant TEST_ONLY commit.

Placement

Describes where or how the plane scans out.

Any change here must move the hash, forcing a re-test. Getting this wrong in the permissive direction — calling a placement property content — is what would let a real geometry change skip validation.

Trait Implementations

impl Clone for PropClass

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for PropClass

impl Debug for PropClass

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

Formats the value using the given formatter.

impl Eq for PropClass

impl Hash for PropClass

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 Ord for PropClass

fn cmp(&self, other: &Self) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

fn clamp_to<R>(self, range: R) -> Self

where Self: Sized, R: ClampBounds<Self>,

🔬This is a nightly-only experimental API. (clamp_to)

Restrict a value to a certain range.

impl PartialEq for PropClass

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

Equality operator ==.

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

Inequality operator !=.

impl PartialOrd for PropClass

fn partial_cmp(&self, other: &Self) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

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

Tests less than (for self and other) and is used by the < operator.

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

Tests less than or equal to (for self and other) and is used by the <= operator.

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

Tests greater than (for self and other) and is used by the > operator.

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

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl StructuralPartialEq for PropClass