Crate type_erased_vec[−][src]
Expand description
This crate provides a single struct TypeErasedVec, which (as its name says) is a type erased Vec.
When you know what its type is, you can get a slice or Vec back using TypeErasedVec::get or TypeErasedVec::get_mut.
Motivation
When communicating with a world outside Rust (GPU for example), it often wants a raw buffer and some kind of type descriptor.
There were two options for expressing this in Rust:
Vec<u8>+ type descriptor.Vec<T>.
The first option is not attractive because Vec<u8> cannot be safely used as Vec<T>, hence we lose the ability of modifying the buffer.
The second option makes all types holding that buffer generic over T, which is not feasible when T must be determined at runtime.
For example, buffers can be loaded from a 3D model file on disk, where the file contains type information to be passed to the 3D renderer.
Leaking
TypeErasedVec (and its companion struct VecMut), as other RAII types, relies on the destructor being called to correctly release resources.
Failing to do so can cause memory leak, for example, through the use of std::mem::forget.
What’s more, the content of TypeErasedVec is only valid after VecMut’s destructor is called.
A TypeErasedVec is said to be in leaked state if the destructor of the returned VecMut of a previous call to get_mut didn’t run.
Calling any method except for TypeErasedVec::is_leaked on a leaked TypeErasedVec results in panic.
Example
use type_erased_vec::TypeErasedVec;
let mut vec = TypeErasedVec::new::<i32>();
let mut vec_mut = unsafe { vec.get_mut() };
for i in 0..10 {
vec_mut.push(i);
}
assert_eq!(*vec_mut, (0..10).collect::<Vec<_>>());