Crate wasmer_runtime

Wasmer-runtime is a library that makes embedding WebAssembly in your application easy, efficient, and safe.

How to use Wasmer-Runtime

The easiest way is to use the instantiate function to create an Instance. Then you can use call or func and then call to call an exported function safely.

Example

Given this WebAssembly:

(module
  (type $t0 (func (param i32) (result i32)))
  (func $add_one (export "add_one") (type $t0) (param $p0 i32) (result i32)
    get_local $p0
    i32.const 1
    i32.add))

compiled into wasm bytecode, we can call the exported add_one function:

static WASM: &'static [u8] = &[
   0x00, 0x61, 0x73, 0x6d, 0x01, 0x00, 0x00, 0x00, 0x01, 0x06, 0x01, 0x60,
   0x01, 0x7f, 0x01, 0x7f, 0x03, 0x02, 0x01, 0x00, 0x07, 0x0b, 0x01, 0x07,
   0x61, 0x64, 0x64, 0x5f, 0x6f, 0x6e, 0x65, 0x00, 0x00, 0x0a, 0x09, 0x01,
   0x07, 0x00, 0x20, 0x00, 0x41, 0x01, 0x6a, 0x0b, 0x00, 0x1a, 0x04, 0x6e,
   0x61, 0x6d, 0x65, 0x01, 0x0a, 0x01, 0x00, 0x07, 0x61, 0x64, 0x64, 0x5f,
   0x6f, 0x6e, 0x65, 0x02, 0x07, 0x01, 0x00, 0x01, 0x00, 0x02, 0x70, 0x30,
];

use wasmer_runtime::{
    instantiate,
    Value,
    imports,
    Func,
};

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let import_object = imports! {};
    let mut instance = instantiate(WASM, &import_object)?;

    let add_one: Func<i32, i32> = instance.exports.get("add_one")?;

    let value = add_one.call(42)?;
    assert_eq!(value, 43);

    Ok(())
}

Modules

cache	The cache module provides the common data structures used by compiler backends to allow serializing compiled wasm code to a binary format. The binary format can be persisted, and loaded to allow skipping compilation and fast startup.
error	The error module contains the data structures and helper functions used to implement errors that are produced and returned from the wasmer runtime.
memory	The memory module contains the implementation data structures and helper functions used to manipulate and access wasm memory.
types	Types used in the Wasm runtime and conversion functions.
units	Various unit types.
wasm	Various types exposed by the Wasmer Runtime.

Macros

func	Helper macro to create a new Func object using the provided function pointer.
imports	Generate an ImportObject easily with the imports! macro.

Structs

Array	The Array marker type. This type can be used like WasmPtr<T, Array> to get access to methods
Ctx	The context of the currently running WebAssembly instance.
DynFunc	Represents a type-erased function provided by either the host or the WebAssembly program.
DynamicFunc	Represents a type-erased function provided by either the host or the WebAssembly program.
Func	Represents a function that can be used by WebAssembly.
Global	A handle to a Wasm Global
ImportObject	All of the import data used when instantiating.
Instance	An instantiated WebAssembly module.
Item	The Item marker type. This is the default and does not usually need to be specified.
Memory	A Wasm linear memory.
Module	A compiled WebAssembly module.
Table	Container with a descriptor and a reference to a table storage.
WasmPtr	A zero-cost type that represents a pointer to something in Wasm linear memory.

Enums

Backend	Enum used to select which compiler should be used to generate code.
Export	An Extern is the runtime representation of an entity that can be imported or exported.
InstantiateError
RuntimeExport	The value of an export passed from one instance to another.

Constants

VERSION

Traits

LikeNamespace

The LikeNamespace trait represents objects that act as a namespace for imports. For example, an Instance or Namespace could be considered namespaces that could provide imports to an instance.

Functions

compile	Compile WebAssembly binary code into a Module. This function is useful if it is necessary to compile a module before it can be instantiated (otherwise, the instantiate function should be used).
compile_with	Compile a Module using the provided compiler from WebAssembly binary code. This function is useful if it is necessary to a compile a module before it can be instantiated and must be used if you wish to use a different backend from the default.
instantiate
load_cache_with	Creates a new module from the given cache Artifact
validate	Perform validation as defined by the WebAssembly specification. Returns true if validation succeeded, false if validation failed.
wat2wasm	Parses in-memory bytes as either the WebAssembly Text format, or a binary WebAssembly module.

Type Definitions

Value

WebAssembly computations manipulate values of basic value types: