Class: Wasmtime::Memory::UnsafeSlice

Inherits:
Object
  • Object
show all
Defined in:
ext/src/ruby_api/memory/unsafe_slice.rs

Overview

Represents a slice of a WebAssembly memory. This is useful for creating Ruby strings from WASM memory without any extra memory allocations.

The returned UnsafeSlice lazily reads the underlying memory, meaning that the actual pointer to the string buffer is not materialzed until #to_str is called.

Instance Method Summary collapse

Instance Method Details

#to_memory_view ⇒ Fiddle::MemoryView

Get this slice as a Fiddle memory view, which can be cheaply read by other Ruby extensions.

Returns:

  • (Fiddle::MemoryView) —

    Memory view of the slice.



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# File 'ext/src/ruby_api/memory/unsafe_slice.rs', line 70

pub fn to_memory_view(rb_self: Obj<Self>) -> Result<Value, Error> {
    static CLASS: Lazy<RClass> = Lazy::new(|_| fiddle_memory_view_class().unwrap());
    let ruby = Ruby::get().unwrap();
    ruby.get_inner(&CLASS).new_instance((rb_self,))
}

#to_str ⇒ String

Gets the memory slice as a Ruby string without copying the underlying buffer.

Returns:

  • (String) —

    Binary String of the memory.



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# File 'ext/src/ruby_api/memory/unsafe_slice.rs', line 81

pub fn to_str(rb_self: Obj<Self>) -> Result<Value, Error> {
    let raw_slice = rb_self.get_raw_slice()?;
    let id = IVAR_NAME.into_id();
    let rstring = unsafe {
        let val = rb_str_new_static(raw_slice.as_ptr() as _, raw_slice.len() as _);
        rb_ivar_set(val, id.as_raw(), rb_self.as_raw());
        rb_obj_freeze(val)
    };

    Ok(unsafe { Value::from_raw(rstring) })
}