Enum wasmtime_runtime::Table

pub enum Table {
    Static {
        data: SendSyncPtr<[Option<SendSyncPtr<u8>>]>,
        size: u32,
        ty: TableElementType,
    },
    Dynamic {
        elements: Vec<Option<SendSyncPtr<u8>>>,
        ty: TableElementType,
        maximum: Option<u32>,
    },
}

Represents an instance’s table.

Variants

Static

A “static” table where storage space is managed externally, currently used with the pooling allocator.

Fields

data: SendSyncPtr<[Option<SendSyncPtr<u8>>]>

Where data for this table is stored. The length of this list is the maximum size of the table.

size: u32

The current size of the table.

ty: TableElementType

The type of this table.

Dynamic

A “dynamic” table where table storage space is dynamically allocated via malloc (aka Rust’s Vec).

Fields

elements: Vec<Option<SendSyncPtr<u8>>>

Dynamically managed storage space for this table. The length of this vector is the current size of the table.

ty: TableElementType

The type of this table.

maximum: Option<u32>

Maximum size that elements can grow to.

Implementations

impl Table

pub fn new_dynamic(plan: &TablePlan, store: &mut dyn Store) -> Result<Self>

Create a new dynamic (movable) table instance for the specified table plan.

pub fn new_static( plan: &TablePlan, data: SendSyncPtr<[Option<SendSyncPtr<u8>>]>, store: &mut dyn Store ) -> Result<Self>

Create a new static (immovable) table instance for the specified table plan.

pub fn element_type(&self) -> TableElementType

Returns the type of the elements in this table.

pub fn size(&self) -> u32

Returns the number of allocated elements.

pub fn maximum(&self) -> Option<u32>

Returns the maximum number of elements at runtime.

Returns None if the table is unbounded.

The runtime maximum may not be equal to the maximum from the table’s Wasm type when it is being constrained by an instance allocator.

pub fn init_func(&mut self, init: *mut VMFuncRef) -> Result<(), Trap>

Initializes the contents of this table to the specified function

pub fn init_funcs( &mut self, dst: u32, items: impl ExactSizeIterator<Item = *mut VMFuncRef> ) -> Result<(), Trap>

Fill table[dst..] with values from items

Returns a trap error on out-of-bounds accesses.

pub fn fill( &mut self, dst: u32, val: TableElement, len: u32 ) -> Result<(), Trap>

Fill table[dst..dst + len] with val.

Returns a trap error on out-of-bounds accesses.

pub unsafe fn grow( &mut self, delta: u32, init_value: TableElement, store: &mut dyn Store ) -> Result<Option<u32>, Error>

Grow table by the specified amount of elements.

Returns the previous size of the table if growth is successful.

Returns None if table can’t be grown by the specified amount of elements, or if the init_value is the wrong kind of table element.

Unsafety

Resizing the table can reallocate its internal elements buffer. This table’s instance’s VMContext has raw pointers to the elements buffer that are used by Wasm, and they need to be fixed up before we call into Wasm again. Failure to do so will result in use-after-free inside Wasm.

Generally, prefer using InstanceHandle::table_grow, which encapsulates this unsafety.

pub fn get(&self, index: u32) -> Option<TableElement>

Get reference to the specified element.

Returns None if the index is out of bounds.

pub fn set(&mut self, index: u32, elem: TableElement) -> Result<(), ()>

Set reference to the specified element.

Errors

Returns an error if index is out of bounds or if this table type does not match the element type.

pub unsafe fn copy( dst_table: *mut Self, src_table: *mut Self, dst_index: u32, src_index: u32, len: u32 ) -> Result<(), Trap>

Copy len elements from src_table[src_index..] into dst_table[dst_index..].

Errors

Returns an error if the range is out of bounds of either the source or destination tables.

pub fn vmtable(&mut self) -> VMTableDefinition

Return a VMTableDefinition for exposing the table to compiled wasm code.

Trait Implementations

impl Default for Table

fn default() -> Self

Returns the “default value” for a type.

impl Drop for Table

fn drop(&mut self)

Executes the destructor for this type.