[−][src]Struct wasmer::Function
A WebAssembly function
instance.
A function instance is the runtime representation of a function.
It effectively is a closure of the original function (defined in either
the host or the WebAssembly module) over the runtime Instance
of its
originating Module
.
The module instance is used to resolve references to other definitions during execution of the function.
Spec: https://webassembly.github.io/spec/core/exec/runtime.html#function-instances
Panics
- Closures (functions with captured environments) are not currently supported
with native functions. Attempting to create a native
Function
with one will result in a panic. Closures as host functions tracking issue
Implementations
impl Function
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pub fn new<F>(store: &Store, ty: &FunctionType, func: F) -> Self where
F: Fn(&[Val]) -> Result<Vec<Val>, RuntimeError> + 'static,
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F: Fn(&[Val]) -> Result<Vec<Val>, RuntimeError> + 'static,
Creates a new host Function
(dynamic) with the provided signature.
Example
let signature = FunctionType::new(vec![Type::I32, Type::I32], vec![Type::I32]); let f = Function::new(&store, &signature, |args| { let sum = args[0].unwrap_i32() + args[1].unwrap_i32(); Ok(vec![Value::I32(sum)]) });
pub fn new_with_env<F, Env>(
store: &Store,
ty: &FunctionType,
env: Env,
func: F
) -> Self where
F: Fn(&Env, &[Val]) -> Result<Vec<Val>, RuntimeError> + 'static,
Env: Sized + WasmerEnv + 'static,
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store: &Store,
ty: &FunctionType,
env: Env,
func: F
) -> Self where
F: Fn(&Env, &[Val]) -> Result<Vec<Val>, RuntimeError> + 'static,
Env: Sized + WasmerEnv + 'static,
Creates a new host Function
(dynamic) with the provided signature and environment.
Example
#[derive(WasmerEnv)] struct Env { multiplier: i32, }; let env = Env { multiplier: 2 }; let signature = FunctionType::new(vec![Type::I32, Type::I32], vec![Type::I32]); let f = Function::new_with_env(&store, &signature, env, |env, args| { let result = env.multiplier * (args[0].unwrap_i32() + args[1].unwrap_i32()); Ok(vec![Value::I32(result)]) });
pub fn new_native<F, Args, Rets, Env>(store: &Store, func: F) -> Self where
F: HostFunction<Args, Rets, WithoutEnv, Env>,
Args: WasmTypeList,
Rets: WasmTypeList,
Env: Sized + 'static,
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F: HostFunction<Args, Rets, WithoutEnv, Env>,
Args: WasmTypeList,
Rets: WasmTypeList,
Env: Sized + 'static,
Creates a new host Function
from a native function.
The function signature is automatically retrieved using the Rust typing system.
Example
fn sum(a: i32, b: i32) -> i32 { a + b } let f = Function::new_native(&store, sum);
pub fn new_native_with_env<F, Args, Rets, Env>(
store: &Store,
env: Env,
func: F
) -> Self where
F: HostFunction<Args, Rets, WithEnv, Env>,
Args: WasmTypeList,
Rets: WasmTypeList,
Env: Sized + WasmerEnv + 'static,
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store: &Store,
env: Env,
func: F
) -> Self where
F: HostFunction<Args, Rets, WithEnv, Env>,
Args: WasmTypeList,
Rets: WasmTypeList,
Env: Sized + WasmerEnv + 'static,
Creates a new host Function
from a native function and a provided environment.
The function signature is automatically retrieved using the Rust typing system.
Example
#[derive(WasmerEnv)] struct Env { multiplier: i32, }; let env = Env { multiplier: 2 }; fn sum_and_multiply(env: &Env, a: i32, b: i32) -> i32 { (a + b) * env.multiplier } let f = Function::new_native_with_env(&store, env, sum_and_multiply);
pub fn ty(&self) -> &FunctionType
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Returns the FunctionType
of the Function
.
Example
fn sum(a: i32, b: i32) -> i32 { a + b } let f = Function::new_native(&store, sum); assert_eq!(f.ty().params(), vec![Type::I32, Type::I32]); assert_eq!(f.ty().results(), vec![Type::I32]);
pub fn store(&self) -> &Store
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Returns the Store
where the Function
belongs.
pub fn param_arity(&self) -> usize
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Returns the number of parameters that this function takes.
Example
fn sum(a: i32, b: i32) -> i32 { a + b } let f = Function::new_native(&store, sum); assert_eq!(f.param_arity(), 2);
pub fn result_arity(&self) -> usize
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Returns the number of results this function produces.
Example
fn sum(a: i32, b: i32) -> i32 { a + b } let f = Function::new_native(&store, sum); assert_eq!(f.result_arity(), 1);
pub fn call(&self, params: &[Val]) -> Result<Box<[Val]>, RuntimeError>
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Call the Function
function.
Depending on where the Function is defined, it will call it.
- If the function is defined inside a WebAssembly, it will call the trampoline for the function signature.
- If the function is defined in the host (in a native way), it will call the trampoline.
Examples
let sum = instance.exports.get_function("sum").unwrap(); assert_eq!(sum.call(&[Value::I32(1), Value::I32(2)]).unwrap().to_vec(), vec![Value::I32(3)]);
pub fn native<Args, Rets>(&self) -> Result<NativeFunc<Args, Rets>, RuntimeError> where
Args: WasmTypeList,
Rets: WasmTypeList,
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Args: WasmTypeList,
Rets: WasmTypeList,
Transform this WebAssembly function into a function with the
native ABI. See NativeFunc
to learn more.
Examples
let sum = instance.exports.get_function("sum").unwrap(); let sum_native = sum.native::<(i32, i32), i32>().unwrap(); assert_eq!(sum_native.call(1, 2).unwrap(), 3);
Errors
If the Args
generic parameter does not match the exported function
an error will be raised:
let sum = instance.exports.get_function("sum").unwrap(); // This results in an error: `RuntimeError` let sum_native = sum.native::<(i64, i64), i32>().unwrap();
If the Rets
generic parameter does not match the exported function
an error will be raised:
let sum = instance.exports.get_function("sum").unwrap(); // This results in an error: `RuntimeError` let sum_native = sum.native::<(i32, i32), i64>().unwrap();
Trait Implementations
impl Clone for Function
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impl Debug for Function
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impl<'a> Exportable<'a> for Function
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pub fn to_export(&self) -> Export
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pub fn get_self_from_extern(
_extern: &'a Extern
) -> Result<&'a Self, ExportError>
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_extern: &'a Extern
) -> Result<&'a Self, ExportError>
impl From<Function> for Extern
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impl From<Function> for Val
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impl<Args, Rets> From<NativeFunc<Args, Rets>> for Function where
Args: WasmTypeList,
Rets: WasmTypeList,
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Args: WasmTypeList,
Rets: WasmTypeList,
pub fn from(other: NativeFunc<Args, Rets>) -> Self
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impl PartialEq<Function> for Function
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impl StructuralPartialEq for Function
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Auto Trait Implementations
impl !RefUnwindSafe for Function
impl Send for Function
impl Sync for Function
impl Unpin for Function
impl !UnwindSafe for Function
Blanket Implementations
impl<T> Any for T where
T: 'static + ?Sized,
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T: 'static + ?Sized,
impl<T> Borrow<T> for T where
T: ?Sized,
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T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
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T: ?Sized,
pub fn borrow_mut(&mut self) -> &mut T
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impl<T> From<T> for T
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impl<T> Instrument for T
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pub fn instrument(self, span: Span) -> Instrumented<Self>
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pub fn in_current_span(self) -> Instrumented<Self>
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impl<T, U> Into<U> for T where
U: From<T>,
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U: From<T>,
impl<T> Pointable for T
pub const ALIGN: usize
type Init = T
The type for initializers.
pub unsafe fn init(init: <T as Pointable>::Init) -> usize
pub unsafe fn deref<'a>(ptr: usize) -> &'a T
pub unsafe fn deref_mut<'a>(ptr: usize) -> &'a mut T
pub unsafe fn drop(ptr: usize)
impl<T> ToOwned for T where
T: Clone,
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T: Clone,
type Owned = T
The resulting type after obtaining ownership.
pub fn to_owned(&self) -> T
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pub fn clone_into(&self, target: &mut T)
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impl<T, U> TryFrom<U> for T where
U: Into<T>,
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U: Into<T>,
type Error = Infallible
The type returned in the event of a conversion error.
pub fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>
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impl<T, U> TryInto<U> for T where
U: TryFrom<T>,
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U: TryFrom<T>,
type Error = <U as TryFrom<T>>::Error
The type returned in the event of a conversion error.
pub fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>
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impl<V, T> VZip<V> for T where
V: MultiLane<T>,
V: MultiLane<T>,