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#![forbid(unsafe_code)]

extern crate wain_ast;

pub mod trap;

mod cast;
mod globals;
mod import;
mod machine;
mod memory;
mod stack;
mod table;
mod value;

pub use import::{
    check_func_signature, DefaultImporter, ImportInvalidError, ImportInvokeError, Importer,
};
pub use machine::Machine;
pub use memory::Memory;
pub use stack::Stack;
pub use value::Value;

use std::io;
use trap::Result;
use wain_ast::Module;

/// A convenient function to execute a WebAssembly module.
///
/// This function takes parsed and validated WebAssembly module and it invokes a start function if
/// presents. Otherwise it invokes a function exported as '_start' with no argument.
///
/// For standard I/O speed, this function locks io::Stdin and io::Stdout objects because currently
/// getchar() and putchar() don't buffer its input/output. This behavior may change in the future.
///
/// If the behavior is not acceptable, please make an abstract machine instance with
/// Machine::instantiate.
///
/// You will need importer for initializing Machine struct. Please use DefaultImporter::with_stdio()
/// or make your own importer struct which implements Importer trait.
pub fn execute(module: &Module<'_>) -> Result<()> {
    let stdin = io::stdin();
    let stdout = io::stdout();
    let importer = DefaultImporter::with_stdio(stdin.lock(), stdout.lock());
    let mut machine = Machine::instantiate(module, importer)?;
    if machine.module().entrypoint.is_none() {
        machine.invoke("_start", &[])?;
    }
    Ok(())
}