Struct WasiStateBuilder 

pub struct WasiStateBuilder { /* private fields */ }

Convenient builder API for configuring WASI via WasiState.

Usage:

let mut state_builder = WasiState::new("wasi-prog-name");
state_builder
   .env("ENV_VAR", "ENV_VAL")
   .arg("--verbose")
   .preopen_dir("src")?
   .map_dir("name_wasi_sees", "path/on/host/fs")?
   .build();

Implementations

impl WasiStateBuilder

pub fn env<Key, Value>( &mut self, key: Key, value: Value, ) -> &mut WasiStateBuilder

where Key: AsRef<[u8]>, Value: AsRef<[u8]>,

Add an environment variable pair.

Both the key and value of an environment variable must not contain a nul byte (0x0), and the key must not contain the = byte (0x3d).

pub fn arg<Arg>(&mut self, arg: Arg) -> &mut WasiStateBuilder

where Arg: AsRef<[u8]>,

Add an argument.

Arguments must not contain the nul (0x0) byte

pub fn envs<I, Key, Value>(&mut self, env_pairs: I) -> &mut WasiStateBuilder

where I: IntoIterator<Item = (Key, Value)>, Key: AsRef<[u8]>, Value: AsRef<[u8]>,

Add multiple environment variable pairs.

Both the key and value of the environment variables must not contain a nul byte (0x0), and the key must not contain the = byte (0x3d).

pub fn args<I, Arg>(&mut self, args: I) -> &mut WasiStateBuilder

where I: IntoIterator<Item = Arg>, Arg: AsRef<[u8]>,

Add multiple arguments.

Arguments must not contain the nul (0x0) byte

pub fn preopen_dir<FilePath>( &mut self, po_dir: FilePath, ) -> Result<&mut WasiStateBuilder, WasiStateCreationError>

where FilePath: AsRef<Path>,

Preopen a directory

This opens the given directory at the virtual root, /, and allows the WASI module to read and write to the given directory.

pub fn preopen<F>( &mut self, inner: F, ) -> Result<&mut WasiStateBuilder, WasiStateCreationError>

where F: Fn(&mut PreopenDirBuilder) -> &mut PreopenDirBuilder,

Preopen a directory and configure it.

Usage:

WasiState::new("program_name")
   .preopen(|p| p.directory("src").read(true).write(true).create(true))?
   .preopen(|p| p.directory(".").alias("dot").read(true))?
   .build()?;

pub fn preopen_dirs<I, FilePath>( &mut self, po_dirs: I, ) -> Result<&mut WasiStateBuilder, WasiStateCreationError>

where I: IntoIterator<Item = FilePath>, FilePath: AsRef<Path>,

Preopen a directory.

This opens the given directory at the virtual root, /, and allows the WASI module to read and write to the given directory.

pub fn preopen_vfs_dirs<I>( &mut self, po_dirs: I, ) -> Result<&mut WasiStateBuilder, WasiStateCreationError>

where I: IntoIterator<Item = String>,

Preopen the given directories from the Virtual FS.

pub fn map_dir<FilePath>( &mut self, alias: &str, po_dir: FilePath, ) -> Result<&mut WasiStateBuilder, WasiStateCreationError>

where FilePath: AsRef<Path>,

Preopen a directory with a different name exposed to the WASI.

pub fn map_dirs<I, FilePath>( &mut self, mapped_dirs: I, ) -> Result<&mut WasiStateBuilder, WasiStateCreationError>

where I: IntoIterator<Item = (String, FilePath)>, FilePath: AsRef<Path>,

Preopen directorys with a different names exposed to the WASI.

pub fn stdout( &mut self, new_file: Box<dyn VirtualFile>, ) -> &mut WasiStateBuilder

Overwrite the default WASI stdout, if you want to hold on to the original stdout use WasiFs::swap_file after building.

pub fn stderr( &mut self, new_file: Box<dyn VirtualFile>, ) -> &mut WasiStateBuilder

Overwrite the default WASI stderr, if you want to hold on to the original stderr use WasiFs::swap_file after building.

pub fn stdin(&mut self, new_file: Box<dyn VirtualFile>) -> &mut WasiStateBuilder

Overwrite the default WASI stdin, if you want to hold on to the original stdin use WasiFs::swap_file after building.

pub fn set_fs(&mut self, fs: Box<dyn FileSystem>) -> &mut WasiStateBuilder

Sets the FileSystem to be used with this WASI instance.

This is usually used in case a custom wasmer_vfs::FileSystem is needed.

pub fn setup_fs( &mut self, setup_fs_fn: Box<dyn Fn(&mut WasiFs) -> Result<(), String> + Send>, ) -> &mut WasiStateBuilder

Configure the WASI filesystem before running.

pub fn build(&mut self) -> Result<WasiState, WasiStateCreationError>

Consumes the WasiStateBuilder and produces a WasiState

Returns the error from WasiFs::new if there’s an error

Calling build multiple times

Calling this method multiple times might not produce a determinisic result. This method is changing the builder’s internal state. The values set with the following methods are reset to their defaults:

• Self::set_fs,
• Self::stdin,
• Self::stdout,
• Self::stderr.

Ideally, the builder must be refactord to update &mut self to mut self for every builder method, but it will break existing code. It will be addressed in a next major release.

pub fn finalize(&mut self) -> Result<WasiEnv, WasiStateCreationError>

Consumes the WasiStateBuilder and produces a WasiEnv

Returns the error from WasiFs::new if there’s an error.

Calling finalize multiple times

Calling this method multiple times might not produce a determinisic result. This method is calling Self::build, which is changing the builder’s internal state. See Self::build’s documentation to learn more.

Trait Implementations

impl Debug for WasiStateBuilder

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl Default for WasiStateBuilder

fn default() -> WasiStateBuilder

Returns the “default value” for a type.