1 files changed, 78 insertions, 0 deletions
diff --git a/src/processes.rs b/src/processes.rs
new file mode 100644
index 0000000..7ac326f
--- /dev/null
+++ b/src/processes.rs
@@ -0,0 +1,78 @@
+use std::collections::HashMap;
+use std::sync::{LazyLock, RwLock, mpsc};
+use std::thread::JoinHandle;
+
+use happylock::ThreadKey;
+use uuid::Uuid;
+
+use crate::pipe::{Message, MessageResponse};
+
+thread_local! {
+	static PROCESS_ID: RwLock<Uuid> = const { RwLock::new(Uuid::nil()) };
+}
+
+static RUNNING_PROCESSES: LazyLock<RwLock<HashMap<Uuid, Process>>> =
+	LazyLock::new(|| RwLock::new(HashMap::new()));
+
+#[derive(Debug)]
+pub struct Process {
+	id: Uuid,
+	thread: JoinHandle<()>,
+	channel: mpsc::Sender<Message>,
+}
+
+pub fn is_builtin(program_id: Uuid) -> bool {
+	program_id.as_u64_pair().0 == 0
+}
+
+pub fn process_id(key: &mut ThreadKey) -> Uuid {
+	PROCESS_ID.with(|id| *id.read().unwrap())
+}
+
+pub fn send_message(key: &mut ThreadKey, program_id: Uuid, message: Message) -> MessageResponse {
+	start_program(key, program_id);
+
+	let programs = RUNNING_PROCESSES.read().unwrap();
+	// TODO: this can crash if the program runs and exits immediately
+	let program = programs.get(&program_id).unwrap();
+
+	let response = MessageResponse::from_message(&message);
+	_ = program.channel.send(message);
+	response
+}
+
+pub fn start_builtin_as(key: &mut ThreadKey, package_id: Uuid, as_program: Uuid) -> Option<()> {
+	let mut processes = RUNNING_PROCESSES.write().unwrap();
+	if processes.contains_key(&as_program) {
+		return Some(());
+	}
+
+	let builtin_index = package_id.as_u64_pair().1 as usize;
+	let func = crate::builtins::BUILTINS.get(builtin_index)?.as_ref()?;
+	let (sender, receiver) = mpsc::channel();
+	let handle = std::thread::spawn(move || {
+		let key = ThreadKey::get().expect("the thread just started");
+		PROCESS_ID.with(|id| {
+			*id.write().unwrap() = as_program;
+		});
+		func(key, receiver);
+	});
+	let process = Process {
+		id: as_program,
+		thread: handle,
+		channel: sender,
+	};
+	processes.insert(as_program, process);
+
+	Some(())
+}
+
+pub fn start_builtin(key: &mut ThreadKey, package_id: Uuid) -> Option<()> {
+	start_builtin_as(key, package_id, package_id)
+}
+
+pub fn start_program(key: &mut ThreadKey, package_id: Uuid) -> Option<()> {
+	start_builtin(key, package_id)?;
+
+	Some(())
+}