Struct Image 

pub struct Image {
    pub code: Vec<u8>,
    pub packed_bitmask: Vec<u8>,
    pub jump_table: Vec<u32>,
    pub endpoints: BTreeMap<u8, EndpointDef>,
    pub memory_mappings: Vec<MemoryMapping>,
    pub gas_slots: Vec<SlotIdx>,
    pub quota_slots: Vec<SlotIdx>,
    pub pinned_slots: BTreeMap<SlotIdx, PinnedCap>,
    pub initial_slots: BTreeMap<SlotIdx, InitialDataCap>,
    pub yield_marker_slot: Option<SlotIdx>,
}

Image: the program spec (code, endpoints, memory layout, slot declarations, pinned ro caps).

pinned_slots and yield_marker_slot reference cnode slots; the kernel installs declared pinned content into the Instance’s cnode at set_image / host_derive_spawn time and treats them as read-only thereafter.

Fields

code: Vec<u8>

Bytecode bytes (validated at construction; see host_make_image).

packed_bitmask: Vec<u8>

Packed bitmask, one bit per code byte, LSB-first. packed_bitmask.len() == code.len().div_ceil(8). A 1 bit marks the start of an instruction; a 0 bit marks a continuation byte. Use javm_exec::unpack_bitmask to recover the unpacked form at decode time.

jump_table: Vec<u32>

Jump-table entries (PVM PCs into code). Indexed by djump immediates.

endpoints: BTreeMap<u8, EndpointDef>

Endpoints addressable by endpoint_idx (u8). Sparse — only declared endpoints are present.

memory_mappings: Vec<MemoryMapping>

Memory layout. Each entry maps a Cap::Data (resolved through source) into the address space at `[start, start

• size). Permissions are derived from whether the target slot appears in pinned_slots` (RO) or not (RW).

gas_slots: Vec<SlotIdx>

Cnode slots holding Cap::Instance[Gas{meter_id}]. Active gas debit comes from the first slot’s meter; the rest are fallback reserves (chain-spec policy).

quota_slots: Vec<SlotIdx>

Cnode slots holding Cap::Instance[Quota{quota_id}]. Symmetric with gas_slots.

pinned_slots: BTreeMap<SlotIdx, PinnedCap>

Pinned read-only caps (Cap::Data or Cap::Image) baked into the spec. The kernel rejects mutations to these slots.

initial_slots: BTreeMap<SlotIdx, InitialDataCap>

Initial cnode state for non-pinned mutable slots. Only honored at standalone (root) Instance bootstrap — a parented Instance receives its cnode from the spawner.

yield_marker_slot: Option<SlotIdx>

Slot holding Cap::Instance[YieldCatcher], if this Instance catches yields. None = no catcher.

Implementations

impl Image

pub fn empty() -> Self

Empty Image: no code, no endpoints, no mappings, no slots. Useful for tests and as a starting point.

Trait Implementations

impl Clone for Image

fn clone(&self) -> Image

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Image

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

Formats the value using the given formatter.

impl Decode for Image

fn is_ssz_fixed_len() -> bool

true iff this type is fixed-length.

fn ssz_fixed_len() -> usize

Number of bytes this type occupies in the fixed-length portion of a container encoding. Variable-length types return BYTES_PER_LENGTH_OFFSET.

fn from_ssz_bytes(bytes: &[u8]) -> Result<Self, DecodeError>

Decode a full instance from bytes, rejecting trailing input.

impl Encode for Image

fn is_ssz_fixed_len() -> bool

true iff this type is fixed-length (no variable-length fields).

fn ssz_fixed_len() -> usize

Number of bytes this type occupies in the fixed-length portion of a container encoding. For variable-length types this returns BYTES_PER_LENGTH_OFFSET (i.e. the size of the offset slot).

fn ssz_bytes_len(&self) -> usize

Total size of self when serialized.

fn ssz_append(&self, buf: &mut Vec<u8>)

Append the encoding of self to buf.

fn is_basic_type() -> bool

true for “basic” SSZ types (uintN, bool), which pack adjacent elements into shared 32-byte chunks for merkleization. Composite types (containers, lists, structs) return false (the default).

fn as_ssz_bytes(&self) -> Vec<u8>

Serialize into a fresh Vec<u8> allocated through the global allocator.

impl HashTreeRoot for Image

fn hash_tree_root<__D: Digest<OutputSize = U32>>(&self) -> [u8; 32]

Compute the hash tree root using D as the underlying hash.

impl PartialEq for Image

fn eq(&self, other: &Image) -> 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 Eq for Image

impl StructuralPartialEq for Image