feat(tiles): initial WASM integration

The first steps towards WASM module integration

2 files changed, 132 insertions, 7 deletions

diff --git a/src/main.rs b/src/main.rs
index 04e5d8de..105f3863 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -11,15 +11,19 @@ mod screen;
 mod terminal_pane;
 mod utils;
 
-use std::io::{Read, Write};
+use std::io::{self, Read, Write};
 use std::os::unix::net::UnixStream;
 use std::path::PathBuf;
 use std::sync::mpsc::{channel, Receiver, Sender};
+use std::sync::{Arc, Mutex};
 use std::thread;
 
 use serde::{Deserialize, Serialize};
 use structopt::StructOpt;
 
+use wasmer::{Exports, Function, Instance, Module, Store, Value};
+use wasmer_wasi::WasiState;
+
 use crate::command_is_executing::CommandIsExecuting;
 use crate::input::input_loop;
 use crate::layout::Layout;
@@ -253,6 +257,108 @@ pub fn start(mut os_input: Box<dyn OsApi>, opts: Opt) {
             .unwrap(),
     );
 
+    // Here be dragons! This is very much a work in progress, and isn't quite functional
+    // yet. It's being left out of the tests because is slows them down massively (by
+    // recompiling a WASM module for every single test). Stay tuned for more updates!
+    #[cfg(not(test))]
+    active_threads.push(
+        thread::Builder::new()
+            .name("wasm".to_string())
+            .spawn(move || {
+                // TODO: Clone shared state here
+                move || -> Result<(), Box<dyn std::error::Error>> {
+                    let store = Store::default();
+
+                    println!("Compiling module...");
+                    // FIXME: Switch to a higher performance compiler (`Store::default()`) and cache this on disk
+                    // I could use `(de)serialize_to_file()` for that
+                    let module = if let Ok(m) = Module::from_file(&store, "strider.wasm") {
+                        m
+                    } else {
+                        return Ok(()); // Just abort this thread quietly if the WASM isn't found
+                    };
+
+                    // FIXME: Upstream the `Pipe` struct
+                    //let output = fluff::Pipe::new();
+                    //let input = fluff::Pipe::new();
+                    let mut wasi_env = WasiState::new("mosaic")
+                        .env("CLICOLOR_FORCE", "1")
+                        .preopen(|p| {
+                            p.directory(".") // TODO: Change this to a more meaningful dir
+                                .alias(".")
+                                .read(true)
+                                .write(true)
+                                .create(true)
+                        })?
+                        //.stdin(Box::new(input))
+                        //.stdout(Box::new(output))
+                        .finalize()?;
+
+                    let mut import_object = wasi_env.import_object(&module)?;
+                    // FIXME: Upstream an `ImportObject` merge method
+                    let mut host_exports = Exports::new();
+                    /* host_exports.insert(
+                        "host_open_file",
+                        Function::new_native_with_env(&store, Arc::clone(&wasi_env.state), host_open_file),
+                    ); */
+                    fn noop() {}
+                    host_exports.insert("host_open_file", Function::new_native(&store, noop));
+                    import_object.register("mosaic", host_exports);
+                    let instance = Instance::new(&module, &import_object)?;
+
+                    // WASI requires to explicitly set the memory for the `WasiEnv`
+                    wasi_env.set_memory(instance.exports.get_memory("memory")?.clone());
+
+                    let start = instance.exports.get_function("_start")?;
+                    let handle_key = instance.exports.get_function("handle_key")?;
+                    let draw = instance.exports.get_function("draw")?;
+
+                    // This eventually calls the `.init()` method
+                    start.call(&[])?;
+
+                    loop {
+                        break;
+                        //let (cols, rows) = terminal::size()?;
+                        //draw.call(&[Value::I32(rows as i32), Value::I32(cols as i32)])?;
+
+                        // FIXME: This downcasting mess needs to be abstracted away
+                        /* let mut state = wasi_env.state();
+                        let wasi_file = state.fs.stdout_mut()?.as_mut().unwrap();
+                        let output: &mut fluff::Pipe = wasi_file.downcast_mut().unwrap();
+                        // Needed because raw mode doesn't implicitly return to the start of the line
+                        write!(
+                            io::stdout(),
+                            "{}\n\r",
+                            output.to_string().lines().collect::<Vec<_>>().join("\n\r")
+                        )?;
+                        output.clear();
+
+                        let wasi_file = state.fs.stdin_mut()?.as_mut().unwrap();
+                        let input: &mut fluff::Pipe = wasi_file.downcast_mut().unwrap();
+                        input.clear(); */
+
+                        /* match event::read()? {
+                            Event::Key(KeyEvent {
+                                code: KeyCode::Char('q'),
+                                ..
+                            }) => break,
+                            Event::Key(e) => {
+                                writeln!(input, "{}\r", serde_json::to_string(&e)?)?;
+                                drop(state);
+                                // Need to release the implicit `state` mutex or I deadlock!
+                                handle_key.call(&[])?;
+                            }
+                            _ => (),
+                        } */
+                    }
+                    debug_log_to_file("WASM module loaded and exited cleanly :)".to_string())?;
+                    Ok(())
+                }()
+                .unwrap()
+            })
+            .unwrap(),
+    );
+
     // TODO: currently we don't push this into active_threads
     // because otherwise the app will hang. Need to fix this so it both
     // listens to the ipc-bus and is able to quit cleanly
diff --git a/src/tests/fakes.rs b/src/tests/fakes.rs
index 22370d98..0afba192 100644
--- a/src/tests/fakes.rs
+++ b/src/tests/fakes.rs
@@ -3,6 +3,7 @@ use ::std::collections::HashMap;
 use ::std::io::{Read, Write};
 use ::std::os::unix::io::RawFd;
 use ::std::path::PathBuf;
+use ::std::sync::atomic::{AtomicBool, Ordering};
 use ::std::sync::{Arc, Mutex};
 use ::std::time::{Duration, Instant};
 
@@ -24,14 +25,20 @@ pub struct FakeStdinReader {
     pub input_chars: Vec<[u8; 10]>,
     pub read_position: usize,
     last_snapshot_time: Arc<Mutex<Instant>>,
+    started_reading_from_pty: Arc<AtomicBool>,
 }
 
 impl FakeStdinReader {
-    pub fn new(input_chars: Vec<[u8; 10]>, last_snapshot_time: Arc<Mutex<Instant>>) -> Self {
+    pub fn new(
+        input_chars: Vec<[u8; 10]>,
+        last_snapshot_time: Arc<Mutex<Instant>>,
+        started_reading_from_pty: Arc<AtomicBool>,
+    ) -> Self {
         FakeStdinReader {
             input_chars,
             read_position: 0,
             last_snapshot_time,
+            started_reading_from_pty,
         }
     }
 }
@@ -39,11 +46,15 @@ impl FakeStdinReader {
 impl Read for FakeStdinReader {
     fn read(&mut self, buf: &mut [u8]) -> Result<usize, std::io::Error> {
         loop {
-            let last_snapshot_time = { *self.last_snapshot_time.lock().unwrap() };
-            if last_snapshot_time.elapsed() > MIN_TIME_BETWEEN_SNAPSHOTS {
-                break;
+            if self.started_reading_from_pty.load(Ordering::Acquire) == false {
+                ::std::thread::sleep(MIN_TIME_BETWEEN_SNAPSHOTS);
             } else {
-                ::std::thread::sleep(MIN_TIME_BETWEEN_SNAPSHOTS - last_snapshot_time.elapsed());
+                let last_snapshot_time = { *self.last_snapshot_time.lock().unwrap() };
+                if last_snapshot_time.elapsed() > MIN_TIME_BETWEEN_SNAPSHOTS {
+                    break;
+                } else {
+                    ::std::thread::sleep(MIN_TIME_BETWEEN_SNAPSHOTS - last_snapshot_time.elapsed());
+                }
             }
         }
         let read_position = self.read_position;
@@ -120,6 +131,7 @@ pub struct FakeInputOutput {
     win_sizes: Arc<Mutex<HashMap<RawFd, PositionAndSize>>>,
     possible_tty_inputs: HashMap<u16, Bytes>,
     last_snapshot_time: Arc<Mutex<Instant>>,
+    started_reading_from_pty: Arc<AtomicBool>,
 }
 
 impl FakeInputOutput {
@@ -137,6 +149,7 @@ impl FakeInputOutput {
             io_events: Arc::new(Mutex::new(vec![])),
             win_sizes: Arc::new(Mutex::new(win_sizes)),
             possible_tty_inputs: get_possible_tty_inputs(),
+            started_reading_from_pty: Arc::new(AtomicBool::new(false)),
         }
     }
     pub fn with_tty_inputs(mut self, tty_inputs: HashMap<u16, Bytes>) -> Self {
@@ -200,6 +213,7 @@ impl OsApi for FakeInputOutput {
                 // them fail
                 ::std::thread::sleep(::std::time::Duration::from_millis(25));
             } else if attempts_left == 0 {
+                self.started_reading_from_pty.store(true, Ordering::Release);
                 return Ok(0);
             }
             let mut read_buffers = self.read_buffers.lock().unwrap();
@@ -213,6 +227,7 @@ impl OsApi for FakeInputOutput {
                     if bytes_read > bytes.read_position {
                         bytes.set_read_position(bytes_read);
                     }
+                    self.started_reading_from_pty.store(true, Ordering::Release);
                     return Ok(bytes_read);
                 }
                 None => {
@@ -245,7 +260,11 @@ impl OsApi for FakeInputOutput {
                 input_chars.push(*bytes);
             }
         }
-        let reader = FakeStdinReader::new(input_chars, self.last_snapshot_time.clone());
+        let reader = FakeStdinReader::new(
+            input_chars,
+            self.last_snapshot_time.clone(),
+            self.started_reading_from_pty.clone(),
+        );
         Box::new(reader)
     }
     fn get_stdout_writer(&self) -> Box<dyn Write> {