267 lines
10 KiB
Rust
267 lines
10 KiB
Rust
use std::collections::{HashMap, HashSet};
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use std::fs;
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use std::path::PathBuf;
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use std::process;
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use std::str::FromStr;
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use std::sync::{mpsc::Sender, Arc, Mutex};
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use std::thread;
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use std::time::{Duration, Instant};
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use serde::{de::DeserializeOwned, Serialize};
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use wasmer::{
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imports, ChainableNamedResolver, Function, ImportObject, Instance, Module, Store, Value,
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WasmerEnv,
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};
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use wasmer_wasi::{Pipe, WasiEnv, WasiState};
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use zellij_tile::data::{Event, EventType, PluginIds};
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use crate::common::errors::ContextType;
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use crate::common::pty::PtyInstruction;
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use crate::common::screen::ScreenInstruction;
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use crate::common::thread_bus::{Bus, ThreadSenders};
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use crate::common::PaneId;
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#[derive(Clone, Debug)]
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pub enum PluginInstruction {
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Load(Sender<u32>, PathBuf),
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Update(Option<u32>, Event), // Focused plugin / broadcast, event data
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Render(Sender<String>, u32, usize, usize), // String buffer, plugin id, rows, cols
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Unload(u32),
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Exit,
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}
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#[derive(WasmerEnv, Clone)]
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pub struct PluginEnv {
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pub plugin_id: u32,
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pub senders: ThreadSenders,
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pub wasi_env: WasiEnv,
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pub subscriptions: Arc<Mutex<HashSet<EventType>>>,
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}
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// Thread main --------------------------------------------------------------------------------------------------------
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pub fn wasm_thread_main(bus: Bus<PluginInstruction>, store: Store, data_dir: PathBuf) {
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let mut plugin_id = 0;
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let mut plugin_map = HashMap::new();
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loop {
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let (event, mut err_ctx) = bus.recv().expect("failed to receive event on channel");
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err_ctx.add_call(ContextType::Plugin((&event).into()));
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match event {
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PluginInstruction::Load(pid_tx, path) => {
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let plugin_dir = data_dir.join("plugins/");
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let wasm_bytes = fs::read(&path)
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.or_else(|_| fs::read(&path.with_extension("wasm")))
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.or_else(|_| fs::read(&plugin_dir.join(&path).with_extension("wasm")))
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.unwrap_or_else(|_| panic!("cannot find plugin {}", &path.display()));
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// FIXME: Cache this compiled module on disk. I could use `(de)serialize_to_file()` for that
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let module = Module::new(&store, &wasm_bytes).unwrap();
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let output = Pipe::new();
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let input = Pipe::new();
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let mut wasi_env = WasiState::new("Zellij")
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.env("CLICOLOR_FORCE", "1")
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.preopen(|p| {
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p.directory(".") // FIXME: Change this to a more meaningful dir
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.alias(".")
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.read(true)
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.write(true)
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.create(true)
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})
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.unwrap()
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.stdin(Box::new(input))
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.stdout(Box::new(output))
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.finalize()
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.unwrap();
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let wasi = wasi_env.import_object(&module).unwrap();
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let plugin_env = PluginEnv {
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plugin_id,
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senders: bus.senders.clone(),
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wasi_env,
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subscriptions: Arc::new(Mutex::new(HashSet::new())),
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};
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let zellij = zellij_exports(&store, &plugin_env);
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let instance = Instance::new(&module, &zellij.chain_back(wasi)).unwrap();
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let start = instance.exports.get_function("_start").unwrap();
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// This eventually calls the `.load()` method
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start.call(&[]).unwrap();
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plugin_map.insert(plugin_id, (instance, plugin_env));
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pid_tx.send(plugin_id).unwrap();
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plugin_id += 1;
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}
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PluginInstruction::Update(pid, event) => {
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for (&i, (instance, plugin_env)) in &plugin_map {
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let subs = plugin_env.subscriptions.lock().unwrap();
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// FIXME: This is very janky... Maybe I should write my own macro for Event -> EventType?
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let event_type = EventType::from_str(&event.to_string()).unwrap();
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if (pid.is_none() || pid == Some(i)) && subs.contains(&event_type) {
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let update = instance.exports.get_function("update").unwrap();
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wasi_write_object(&plugin_env.wasi_env, &event);
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update.call(&[]).unwrap();
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}
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}
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drop(bus.senders.send_to_screen(ScreenInstruction::Render));
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}
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PluginInstruction::Render(buf_tx, pid, rows, cols) => {
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let (instance, plugin_env) = plugin_map.get(&pid).unwrap();
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let render = instance.exports.get_function("render").unwrap();
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render
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.call(&[Value::I32(rows as i32), Value::I32(cols as i32)])
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.unwrap();
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buf_tx.send(wasi_read_string(&plugin_env.wasi_env)).unwrap();
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}
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PluginInstruction::Unload(pid) => drop(plugin_map.remove(&pid)),
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PluginInstruction::Exit => break,
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}
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}
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}
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// Plugin API ---------------------------------------------------------------------------------------------------------
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pub fn zellij_exports(store: &Store, plugin_env: &PluginEnv) -> ImportObject {
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macro_rules! zellij_export {
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($($host_function:ident),+ $(,)?) => {
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imports! {
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"zellij" => {
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$(stringify!($host_function) =>
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Function::new_native_with_env(store, plugin_env.clone(), $host_function),)+
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}
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}
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}
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}
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zellij_export! {
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host_subscribe,
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host_unsubscribe,
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host_set_invisible_borders,
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host_set_max_height,
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host_set_selectable,
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host_get_plugin_ids,
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host_open_file,
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host_set_timeout,
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}
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}
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fn host_subscribe(plugin_env: &PluginEnv) {
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let mut subscriptions = plugin_env.subscriptions.lock().unwrap();
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let new: HashSet<EventType> = wasi_read_object(&plugin_env.wasi_env);
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subscriptions.extend(new);
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}
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fn host_unsubscribe(plugin_env: &PluginEnv) {
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let mut subscriptions = plugin_env.subscriptions.lock().unwrap();
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let old: HashSet<EventType> = wasi_read_object(&plugin_env.wasi_env);
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subscriptions.retain(|k| !old.contains(k));
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}
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fn host_set_selectable(plugin_env: &PluginEnv, selectable: i32) {
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let selectable = selectable != 0;
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plugin_env
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.senders
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.send_to_screen(ScreenInstruction::SetSelectable(
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PaneId::Plugin(plugin_env.plugin_id),
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selectable,
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))
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.unwrap()
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}
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fn host_set_max_height(plugin_env: &PluginEnv, max_height: i32) {
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let max_height = max_height as usize;
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plugin_env
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.senders
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.send_to_screen(ScreenInstruction::SetMaxHeight(
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PaneId::Plugin(plugin_env.plugin_id),
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max_height,
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))
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.unwrap()
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}
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fn host_set_invisible_borders(plugin_env: &PluginEnv, invisible_borders: i32) {
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let invisible_borders = invisible_borders != 0;
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plugin_env
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.senders
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.send_to_screen(ScreenInstruction::SetInvisibleBorders(
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PaneId::Plugin(plugin_env.plugin_id),
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invisible_borders,
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))
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.unwrap()
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}
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fn host_get_plugin_ids(plugin_env: &PluginEnv) {
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let ids = PluginIds {
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plugin_id: plugin_env.plugin_id,
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zellij_pid: process::id(),
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};
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wasi_write_object(&plugin_env.wasi_env, &ids);
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}
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fn host_open_file(plugin_env: &PluginEnv) {
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let path: PathBuf = wasi_read_object(&plugin_env.wasi_env);
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plugin_env
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.senders
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.send_to_pty(PtyInstruction::SpawnTerminal(Some(path)))
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.unwrap();
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}
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fn host_set_timeout(plugin_env: &PluginEnv, secs: f64) {
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// There is a fancy, high-performance way to do this with zero additional threads:
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// If the plugin thread keeps a BinaryHeap of timer structs, it can manage multiple and easily `.peek()` at the
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// next time to trigger in O(1) time. Once the wake-up time is known, the `wasm` thread can use `recv_timeout()`
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// to wait for an event with the timeout set to be the time of the next wake up. If events come in in the meantime,
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// they are handled, but if the timeout triggers, we replace the event from `recv()` with an
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// `Update(pid, TimerEvent)` and pop the timer from the Heap (or reschedule it). No additional threads for as many
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// timers as we'd like.
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//
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// But that's a lot of code, and this is a few lines:
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let send_plugin_instructions = plugin_env.senders.to_plugin.clone();
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let update_target = Some(plugin_env.plugin_id);
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thread::spawn(move || {
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let start_time = Instant::now();
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thread::sleep(Duration::from_secs_f64(secs));
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// FIXME: The way that elapsed time is being calculated here is not exact; it doesn't take into account the
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// time it takes an event to actually reach the plugin after it's sent to the `wasm` thread.
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let elapsed_time = Instant::now().duration_since(start_time).as_secs_f64();
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send_plugin_instructions
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.unwrap()
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.send(PluginInstruction::Update(
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update_target,
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Event::Timer(elapsed_time),
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))
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.unwrap();
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});
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}
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// Helper Functions ---------------------------------------------------------------------------------------------------
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// FIXME: Unwrap city
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pub fn wasi_read_string(wasi_env: &WasiEnv) -> String {
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let mut state = wasi_env.state();
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let wasi_file = state.fs.stdout_mut().unwrap().as_mut().unwrap();
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let mut buf = String::new();
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wasi_file.read_to_string(&mut buf).unwrap();
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buf
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}
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pub fn wasi_write_string(wasi_env: &WasiEnv, buf: &str) {
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let mut state = wasi_env.state();
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let wasi_file = state.fs.stdin_mut().unwrap().as_mut().unwrap();
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writeln!(wasi_file, "{}\r", buf).unwrap();
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}
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pub fn wasi_write_object(wasi_env: &WasiEnv, object: &impl Serialize) {
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wasi_write_string(wasi_env, &serde_json::to_string(&object).unwrap());
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}
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pub fn wasi_read_object<T: DeserializeOwned>(wasi_env: &WasiEnv) -> T {
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let json = wasi_read_string(wasi_env);
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serde_json::from_str(&json).unwrap()
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}
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