We use `VecDeque::drain` to read the captured stream, zipped with the
given buffer. We could expect that only the yielded items from the
`drain` will be removed, but actually no. Reading [the
documentation](https://doc.rust-lang.org/std/collections/struct.VecDeque.html#method.drain):
> Note 1: The element `range` is removed even if the iterator is not
> consumed until the end.
So by using a range like `..` will drain the entire captured stream,
whatever we read from it. Said differently, if the given buffer length
is smaller than the captured stream, the first read will drain the
entire captured stream.
This patch fixes the problem by specifying a better range:
`..min(inner_buffer.len(), oc.buffer.len())`.
With this new range, it's actually useless to increment
`num_bytes_written`, we already know ahead of time the amount of bytes
we are going to read. Consequently, the patch simplifies this code a
little bit more.
On Windows, using a `u32` representation for `wasi_version_t` fails if
a C++ compiler is used to treat a C program. So we change our strategy
here. We use a C representation to be FFI-safe, and the
`INVALID_VERSION` variant is now set to -1 instead of `u32::MAX`.
This patch also adds unit tests for `wasi_get_wasi_version` so that we
are sure of the behavior of this `type` on all platforms.
First, let's no longer derive from `Default` for `wasi_config_t`. By
default, we want to inherit `stdin`, `stdout` and `stderr`. The
default for `bool` is `false`; we want `true` here.
Second, let's update `wasi_config_new` to correctly set `inherit_*`
fields to `true`.
Third, lets' create `wasi_config_capture_*` functions. By default,
`std*` are inherited, so we need functions to capture them. That's the
new feature this patch introduces. The `wasi_config_inherit_*`
functions are kept for the sake of backward compatibility. Ideally, we
would want an API like `wasi_config_capture_*(capture: bool)`, but it
would duplicate the API somehow.
Fourth, let's fix `wasi_env_new`. We want to capture `stdout` and
`stderr` if and only if the `inherit_*` fields are set to
`false`. There was bug here. That's why everything was working
correctly by the way: `bool::default()` is `false`, and we have this
inverted condition here, so everything was working as expected because
of a double error. The only bug was that it wasn't possible to capture
`std*` before.
I hope this little change will clarify a little bit that the `Export`
passed to `Extern::from_vm_export` is not a `wasmer::Export` but a
`wasmer_vm::Export`.
`wasm_store_t` is now a proper struct (rather than an opaque type) of
kind:
```rs
struct wasm_store_t {
inner: Store
}
```
The rest of the patch updates the code accordingly.
