Fully support WASM (in some contexts)

1 files changed, 121 insertions, 0 deletions

diff --git a/src/script/wasm.rs b/src/script/wasm.rs
new file mode 100644
index 0000000..96190f6
--- /dev/null
+++ b/src/script/wasm.rs
@@ -0,0 +1,121 @@
+use std::time::UNIX_EPOCH;
+
+use crossterm::{event::KeyCode, style::ContentStyle};
+use wasmi::{Caller, Engine, Linker};
+
+use crate::{buffer::Cell, script::ScriptContext};
+
+fn add_cell(mut caller: Caller<&mut ScriptContext>, character: u32, location: u32, z: u32) {
+	caller.data_mut().buffer.cells.push(Cell {
+		character: char::from_u32(character).unwrap_or_default(),
+		style: ContentStyle::new(),
+		x: (location >> 16) as u16,
+		y: (location & 0xffff) as u16,
+		z: z as u8,
+	});
+}
+
+fn window_size(caller: Caller<&mut ScriptContext>) -> u32 {
+	let window_size = &caller.data().buffer.window_size;
+	((window_size.rows as u32) << 16) | (window_size.columns as u32)
+}
+
+fn is_key_pressed_this_frame(caller: Caller<&mut ScriptContext>, key_code: u32) -> u32 {
+	const BACKSPACE: u32 = 1 << 24;
+	const ENTER: u32 = 2 << 24;
+	const LEFT: u32 = 3 << 24;
+	const RIGHT: u32 = 4 << 24;
+	const UP: u32 = 5 << 24;
+	const DOWN: u32 = 6 << 24;
+	const HOME: u32 = 7 << 24;
+	const END: u32 = 8 << 24;
+	const PAGE_UP: u32 = 9 << 24;
+	const PAGE_DOWN: u32 = 10 << 24;
+	const TAB: u32 = 11 << 24;
+	const BACK_TAB: u32 = 12 << 24;
+	const DELETE: u32 = 13 << 24;
+	const INSERT: u32 = 14 << 24;
+	const F: u32 = 15 << 24;
+	const CHAR: u32 = 16 << 24;
+	const ESC: u32 = 17 << 24;
+	let key_code = match key_code {
+		0 => KeyCode::Null,
+		BACKSPACE => KeyCode::Backspace,
+		ENTER => KeyCode::Enter,
+		LEFT => KeyCode::Left,
+		RIGHT => KeyCode::Right,
+		UP => KeyCode::Up,
+		DOWN => KeyCode::Down,
+		HOME => KeyCode::Home,
+		END => KeyCode::End,
+		PAGE_UP => KeyCode::PageUp,
+		PAGE_DOWN => KeyCode::PageDown,
+		TAB => KeyCode::Tab,
+		BACK_TAB => KeyCode::BackTab,
+		DELETE => KeyCode::Delete,
+		INSERT => KeyCode::Insert,
+		F..CHAR => KeyCode::F((key_code & 0xff) as u8),
+		CHAR..ESC => KeyCode::Char(char::from_u32(key_code & 0xffffff).unwrap_or_default()),
+		ESC => KeyCode::Esc,
+		_ => KeyCode::Null,
+	};
+
+	if caller.data().input.is_key_pressed_this_frame(key_code) {
+		1
+	} else {
+		0
+	}
+}
+
+fn exit(mut caller: Caller<&mut ScriptContext>) {
+	let _ = caller.data_mut().buffer.finish();
+	std::process::exit(0);
+}
+
+fn random_u64() -> u64 {
+	getrandom::u64().unwrap_or(4)
+}
+
+fn system_now(caller: Caller<&mut ScriptContext>) -> u64 {
+	caller
+		.data()
+		.time
+		.system_now()
+		.duration_since(UNIX_EPOCH)
+		.unwrap()
+		.as_nanos() as u64
+}
+
+fn monotonic_now(caller: Caller<&mut ScriptContext>) -> u64 {
+	caller.data().time.monotonic_now().as_nanos() as u64
+}
+
+fn delta_time(caller: Caller<&mut ScriptContext>) -> u64 {
+	caller.data().time.delta_time().as_nanos() as u64
+}
+
+pub fn linker<'ctx>(
+	engine: &Engine,
+) -> Result<wasmi::Linker<&'ctx mut ScriptContext<'ctx>>, wasmi::Error> {
+	macro_rules! add_fns {
+		($linker: expr, [$($func: ident),*]) => {
+			$($linker.func_wrap("tortuise", stringify!($func), $func)?;)*
+		};
+	}
+
+	let mut linker = Linker::new(engine);
+	add_fns!(
+		linker,
+		[
+			add_cell,
+			window_size,
+			is_key_pressed_this_frame,
+			exit,
+			random_u64,
+			system_now,
+			monotonic_now,
+			delta_time
+		]
+	);
+	Ok(linker)
+}