Struct wasmer_vm::InstanceHandle

pub struct InstanceHandle { /* fields omitted */ }

A handle holding an Instance of a WebAssembly module.

Implementations

impl InstanceHandle

pub fn set_signal_handler<H>(&self, handler: H) where
    H: 'static + Fn(c_int, *const siginfo_t, *const c_void) -> bool, 

Set a custom signal handler

impl InstanceHandle

pub fn allocate_instance(module: &ModuleInfo) -> (NonNull<u8>, VMOffsets)

Allocates an instance for use with InstanceHandle::new.

Returns the instance pointer and the VMOffsets that describe the memory buffer pointed to by the instance pointer.

pub unsafe fn memory_definition_locations(
    instance_ptr: NonNull<u8>,
    offsets: &VMOffsets
) -> Vec<NonNull<VMMemoryDefinition>>

Get the locations of where the local VMMemoryDefinitions should be stored.

This function lets us create Memory objects on the host with backing memory in the VM.

Safety

• instance_ptr must point to enough memory that all of the offsets in offsets point to valid locations in memory.

pub unsafe fn table_definition_locations(
    instance_ptr: NonNull<u8>,
    offsets: &VMOffsets
) -> Vec<NonNull<VMTableDefinition>>

Get the locations of where the VMTableDefinitions should be stored.

This function lets us create Table objects on the host with backing memory in the VM.

Safety

• instance_ptr must point to enough memory that all of the offsets in offsets point to valid locations in memory.

pub unsafe fn new(
    instance_ptr: NonNull<u8>,
    offsets: VMOffsets,
    module: Arc<ModuleInfo>,
    finished_functions: BoxedSlice<LocalFunctionIndex, FunctionBodyPtr>,
    finished_function_call_trampolines: BoxedSlice<SignatureIndex, VMTrampoline>,
    finished_memories: BoxedSlice<LocalMemoryIndex, Arc<dyn Memory>>,
    finished_tables: BoxedSlice<LocalTableIndex, Arc<dyn Table>>,
    finished_globals: BoxedSlice<LocalGlobalIndex, Arc<Global>>,
    imports: Imports,
    vmshared_signatures: BoxedSlice<SignatureIndex, VMSharedSignatureIndex>,
    host_state: Box<dyn Any>
) -> Result<Self, Trap>

Create a new InstanceHandle pointing at a new Instance.

Safety

This method is not necessarily inherently unsafe to call, but in general the APIs of an Instance are quite unsafe and have not been really audited for safety that much. As a result the unsafety here on this method is a low-overhead way of saying "this is an extremely unsafe type to work with".

Extreme care must be taken when working with InstanceHandle and it's recommended to have relatively intimate knowledge of how it works internally if you'd like to do so. If possible it's recommended to use the wasmer crate API rather than this type since that is vetted for safety.

However the following must be taken care of before calling this function:

• instance_ptr must point to valid memory sufficiently large for there Instance.
• The memory at instance.tables_ptr() must be initialized with data for all the local tables.
• The memory at instance.memories_ptr() must be initialized with data for all the local memories.

pub unsafe fn finish_instantiation(
    &self,
    data_initializers: &[DataInitializer<'_>]
) -> Result<(), Trap>

Finishes the instantiation process started by Instance::new.

Safety

Only safe to call immediately after instantiation.

pub unsafe fn from_vmctx(vmctx: *mut VMContext) -> Self

Create a new InstanceHandle pointing at the instance pointed to by the given VMContext pointer.

Safety

This is unsafe because it doesn't work on just any VMContext, it must be a VMContext allocated as part of an Instance.

pub fn vmctx(&self) -> &VMContext

Return a reference to the vmctx used by compiled wasm code.

pub fn vmctx_ptr(&self) -> *mut VMContext

Return a raw pointer to the vmctx used by compiled wasm code.

pub fn module(&self) -> &Arc<ModuleInfo>

Return a reference-counting pointer to a module.

pub fn module_ref(&self) -> &ModuleInfo

Return a reference to a module.

pub fn lookup(&self, field: &str) -> Option<Export>

Lookup an export with the given name.

pub fn lookup_by_declaration(&self, export: &ExportIndex) -> Export

Lookup an export with the given export declaration.

pub fn exports(&self) -> Iter<'_, String, ExportIndex>

Return an iterator over the exports of this instance.

Specifically, it provides access to the key-value pairs, where the keys are export names, and the values are export declarations which can be resolved lookup_by_declaration.

pub fn host_state(&self) -> &dyn Any

Return a reference to the custom state attached to this instance.

pub fn memory_index(&self, memory: &VMMemoryDefinition) -> LocalMemoryIndex

Return the memory index for the given VMMemoryDefinition in this instance.

pub fn memory_grow<IntoPages>(
    &self,
    memory_index: LocalMemoryIndex,
    delta: IntoPages
) -> Result<Pages, MemoryError> where
    IntoPages: Into<Pages>, 

Grow memory in this instance by the specified amount of pages.

Returns None if memory can't be grown by the specified amount of pages.

pub fn table_index(&self, table: &VMTableDefinition) -> LocalTableIndex

Return the table index for the given VMTableDefinition in this instance.

pub fn table_grow(
    &self,
    table_index: LocalTableIndex,
    delta: u32
) -> Option<u32>

Grow table in this instance by the specified amount of pages.

Returns None if memory can't be grown by the specified amount of pages.

pub fn table_get(
    &self,
    table_index: LocalTableIndex,
    index: u32
) -> Option<VMCallerCheckedAnyfunc>

Get table element reference.

Returns None if index is out of bounds.

pub fn table_set(
    &self,
    table_index: LocalTableIndex,
    index: u32,
    val: VMCallerCheckedAnyfunc
) -> Result<(), Trap>

Set table element reference.

Returns an error if the index is out of bounds

pub fn get_local_table(&self, index: LocalTableIndex) -> &dyn Table

Get a table defined locally within this module.

pub unsafe fn dealloc(&self)

Deallocates memory associated with this instance.

Safety

This is unsafe because there might be other handles to this InstanceHandle elsewhere, and there's nothing preventing usage of this handle after this function is called.

Trait Implementations

impl Clone for InstanceHandle

fn clone(&self) -> Self

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Eq for InstanceHandle

impl Hash for InstanceHandle

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, 

Feeds a slice of this type into the given Hasher.

impl PartialEq<InstanceHandle> for InstanceHandle

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

This method tests for self and other values to be equal, and is used by ==.

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

This method tests for !=.

impl Send for InstanceHandle

Safety

This is safe because there is no thread-specific logic in InstanceHandle. TODO: this needs extra review

impl StructuralEq for InstanceHandle

impl StructuralPartialEq for InstanceHandle