Handle Array Arguments Better

[vixalien]

Hello again. This PR is currently a draft because while it does not depend on #17, the code there needs to be merged before this one because by doing so, the code in this PR will be vastly simplified.

This PR does 3 main things:

1. Unbox C Arrays into TypedArrays (Uint8Array, Uint16Array etc..)

This is similar to GJS behaviour and differs from the current behaviour where each element would be unboxed into an argument. This doesn't work for stuff like GLib.file_get_contents, which returns an array, but the array is of random data. This PR would, for example, produce a Uint8Array instead of an array of numbers.

2. Utilise the lengthArg to unboxArrays

Functions that return an array usually have a length parameter. For the GLib.file_get_contents case, that parameter is called length. The bindings now automatically infer the array's length from the related parameter.

3. Omit the length parameter from being returned.

In the case of the above function, since GLib.file_get_contents returns an array, the length parameter is no longer required as we can infer that from Uint8Array.length and adds to the noise. This behaviour is what GJS does, too.

TODO in a separate PR: Handle different arrays based on the GIArrayType. Currently, deno_gi only handles C arrays, but there are other types of arrays namely: GArray, GPtrArray and GByteArray. Adding support for them should be pretty straightforward. Maybe an issue needs to be filed to keep track of this.

[vixalien]

Actually, I believe all arguments should be initialised to an empty pointer (GIArgInfo)

[vixalien]

TODO: handle return values' length DONE

Here's some test code for this:

import { require } from "../mod.ts";

const GLib = require("GLib", "2.0");

const encoder = new TextEncoder();
const decoder = new TextDecoder();

const bfr = encoder.encode("Hello, World!");

const bytes = GLib.Bytes.new(bfr, bfr.length);

// console.log("size", bytes.getSize());

const data = bytes.getData();
console.log("data", data);

Although currently, it seems GLib.Bytes.getData() doesn't set the size argument. this needs to be investigated.