Struct Vm

pub struct Vm { /* private fields */ }

A Vm is a thin wrapper around an instance of wasmi::Module. Multiple Vms may be held in a single Host, and each contains a single WASM module instantiation.

Vm rejects modules with either floating point or start functions.

Vm is configured to use its Host as a source of WASM imports. Specifically Host implements [wasmi::ImportResolver] by resolving all and only the functions declared in Env as imports, if requested by the WASM module. Any other lookups on any tables other than import functions will fail.

Implementations

impl Vm

pub const MAX_VM_ARGS: usize = 32usize

The maximum number of arguments that can be passed to a VM function.

pub fn get_all_host_functions() -> Vec<(&'static str, &'static str, u32)>

pub fn get_all_host_functions_with_supported_protocol_range() -> Vec<(&'static str, &'static str, u32, Option<u32>, Option<u32>)>

pub fn from_parsed_module( host: &Host, contract_id: Hash, parsed_module: Rc<ParsedModule>, ) -> Result<Rc<Self>, HostError>

pub fn new( host: &Host, contract_id: Hash, wasm: &[u8], ) -> Result<Rc<Self>, HostError>

Constructs a new instance of a Vm within the provided Host, establishing a new execution context for a contract identified by contract_id with Wasm bytecode provided in module_wasm_code.

This function performs several steps:

• Parses and performs Wasm validation on the module.
• Checks that the module contains an [meta::INTERFACE_VERSION] that matches the host.
• Checks that the module has no floating point code or start function, or post-MVP wasm extensions.
• Instantiates the module, leaving it ready to accept function invocations.
• Looks up and caches its linear memory export named memory if it exists.

With the introduction of the granular cost inputs this method should only be used for the one-off full parses of the new Wasms during the initial upload verification.

pub fn custom_section(&self, name: impl AsRef<str>) -> Option<&[u8]>

Returns the raw bytes content of a named custom section from the WASM module loaded into the Vm, or None if no such custom section exists.

Trait Implementations

impl Hash for Vm

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.