Struct RangeMeta 

#[non_exhaustive]
pub struct RangeMeta {
    pub total_length: Option<u64>,
    pub chunk_lens: Option<Vec<u64>>,
    pub chunk_count: Option<u64>,
    pub chunk_index: Option<u64>,
    pub root: Option<String>,
    pub inclusion_proof: Option<String>,
}

The verification metadata a range’s frames carry (L7 §9): the whole-resource shape a downloader uses to establish or check the ResourceCommitment.

Read this as “the stream’s declared identity”, not “frame 1’s fields”

total_length, chunk_lens, chunk_count and root describe the WHOLE resource, so every frame of a conforming stream repeats the same values. assemble_range_stream therefore captures them from the first frame and RE-CHECKS every later frame against them — a holder that revises its declared shape mid-stream is rejected rather than silently believed on whichever frame arrived first. chunk_index is the one field that legitimately varies per frame; see its own note.

#[non_exhaustive]: the L7 range preamble gains optional fields as the wire grows (chunk_count and the paged prologue are recent additions), and each one arrives here. Build one with from_frame or from Default plus the declaring_* setters.

Fields (Non-exhaustive)

Non-exhaustive structs could have additional fields added in future. Therefore, non-exhaustive structs cannot be constructed in external crates using the traditional Struct { .. } syntax; cannot be matched against without a wildcard ..; and struct update syntax will not work.

total_length: Option<u64>

The full resource ciphertext length.

chunk_lens: Option<Vec<u64>>

Per-chunk ciphertext lengths of the whole resource, in order. For a resource whose layout is too large to state on one frame this is one PAGE of the array rather than all of it — which is why chunk_count exists to say how many entries the whole array has.

chunk_count: Option<u64>

How many entries the whole resource’s chunk_lens array has.

Present so a reader can tell a COMPLETE single-frame layout from one page of a paged prologue: chunk_lens.len() < chunk_count means the array continues on later frames. Absent means the holder declared no count, and chunk_lens is taken to be the whole array (the pre-paging shape, which stays readable — §5.1).

chunk_index: Option<u64>

Index into chunk_lens of the first chunk in THIS frame.

Unlike the other fields this is per-frame, not per-resource: a chunk-aligned continuation frame states where it begins. Frames arrive in ascending byte offset, so the declared index is non-decreasing across a conforming stream.

root: Option<String>

The chain-anchored generation root (64-hex).

inclusion_proof: Option<String>

The whole-resource merkle inclusion proof (base64), or None for a capsule.

Implementations

impl RangeMeta

pub fn from_frame(frame: &RangeFrame) -> Self

The verification metadata one RangeFrame declares.

pub fn declaring_layout( self, total_length: u64, chunk_lens: Vec<u64>, chunk_count: u64, ) -> Self

Declare the whole-resource shape (total_length + chunk_lens + the array’s chunk_count). The #[non_exhaustive] construction path for a test fixture or a non-dig-nat transport.

pub fn declaring_anchor( self, root: String, inclusion_proof: Option<String>, ) -> Self

Declare the chain anchor (root + the whole-resource inclusion_proof).

pub fn declaring_chunk_index(self, chunk_index: u64) -> Self

Declare which chunk of the resource this frame’s bytes begin at.

Trait Implementations

impl Clone for RangeMeta

fn clone(&self) -> RangeMeta

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for RangeMeta

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

Formats the value using the given formatter.

impl Default for RangeMeta

fn default() -> RangeMeta

Returns the “default value” for a type.

impl Eq for RangeMeta

impl PartialEq for RangeMeta

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for RangeMeta