From 4694d4eb1d22103ab83f139ca95ed5d9ceb95f33 Mon Sep 17 00:00:00 2001
From: Tom Gowan <s3549186@student.rmit.edu.au>
Date: Fri, 26 Apr 2019 17:50:38 +1000
Subject: [PATCH] watcher

---
 src/lib.rs   |   7 +++-
 src/watch.rs | 107 +++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 112 insertions(+), 2 deletions(-)
 create mode 100644 src/watch.rs

diff --git a/src/lib.rs b/src/lib.rs
index f24bf7a..baf3426 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -2,15 +2,17 @@ mod compiler;
 mod error;
 mod reflection;
 mod srvk;
-mod layouts;
+pub mod layouts;
+mod watch;
 
 pub use layouts::*;
 pub use reflection::LayoutData;
+pub use watch::{Message, Watch};
+pub use error::Error;
 
 use spirv_reflect as sr;
 use vulkano as vk;
 use std::path::Path;
-use error::Error;
 use shaderc::ShaderKind;
 
 pub struct CompiledShaders {
@@ -18,6 +20,7 @@ pub struct CompiledShaders {
     pub fragment: Vec<u32>,
 }
 
+
 pub fn load<T>(vertex: T, fragment: T) -> Result<CompiledShaders, Error>
 where
     T: AsRef<Path>,
diff --git a/src/watch.rs b/src/watch.rs
new file mode 100644
index 0000000..8b855de
--- /dev/null
+++ b/src/watch.rs
@@ -0,0 +1,107 @@
+use std::sync::mpsc;
+use notify::{RecommendedWatcher, RecursiveMode, Watcher};
+use std::thread;
+use std::time::Duration;
+use std::path::{Path, PathBuf};
+use crate::layouts::Entry;
+use crate::CompiledShaders;
+use std::sync::mpsc::{Sender, Receiver};
+use crate::error::Error;
+
+pub struct Watch {
+    _handler: Handler,
+    pub rx: Receiver<Result<Message, Error>>,
+}
+
+struct Loader {
+    vertex: PathBuf,
+    fragment: PathBuf,
+    tx: Sender<Result<Message, Error>>,
+}
+
+pub struct Message {
+    pub shaders: CompiledShaders,
+    pub entry: Entry,
+}
+
+impl Watch {
+    pub fn new<T>(vertex: T, fragment: T) -> Self
+        where
+        T: AsRef<Path>,
+        {
+            let (handler, rx) = create_watch(vertex.as_ref().to_path_buf(), fragment.as_ref().to_path_buf());
+            Watch{_handler: handler, rx}
+        }
+}
+
+impl Loader {
+    fn create(vertex: PathBuf, fragment: PathBuf) -> (Self, Receiver<Result<Message, Error>>) {
+    let (tx, rx) = mpsc::channel();
+        let loader = Loader{
+            vertex,
+            fragment,
+            tx,
+        };
+        loader.reload();
+        (loader, rx)
+    }
+
+    fn reload(&self) {
+        match crate::load(&self.vertex, &self.fragment) {
+            Ok(shaders) => {
+                let entry = crate::parse(&shaders);
+                self.tx.send(Ok(Message{ shaders, entry })).ok()
+                },
+            Err(e) => self.tx.send(Err(e)).ok(),
+        };
+    }
+}
+
+struct Handler {
+    thread_tx: mpsc::Sender<()>,
+    handle: Option<thread::JoinHandle<()>>,
+    _watcher: RecommendedWatcher,
+}
+
+impl Drop for Handler {
+    fn drop(&mut self) {
+        self.thread_tx.send(()).ok();
+        if let Some(h) = self.handle.take() {
+            h.join().ok();
+        }
+    }
+}
+
+
+fn create_watch(vert_path: PathBuf, frag_path: PathBuf) -> (Handler, mpsc::Receiver<Result<Message, Error>>) {
+    let (notify_tx, notify_rx) = mpsc::channel();
+    let (thread_tx, thread_rx) = mpsc::channel();
+    let mut watcher: RecommendedWatcher =
+        Watcher::new(notify_tx, Duration::from_millis(50)).expect("failed to create watcher");
+
+    watcher
+        .watch(&vert_path, RecursiveMode::NonRecursive)
+        .expect("failed to add vertex shader to notify");
+    watcher
+        .watch(&frag_path, RecursiveMode::NonRecursive)
+        .expect("failed to add fragment shader to notify");
+
+
+    let (loader, rx) = Loader::create(vert_path, frag_path);
+
+    let handle = thread::spawn(move || 'watch_loop: loop {
+        if let Ok(_) = thread_rx.try_recv() {
+            break 'watch_loop;
+        }
+        if let Ok(notify::DebouncedEvent::Create(_)) = notify_rx.recv_timeout(Duration::from_secs(1)) {
+            loader.reload();
+        }
+    });
+    let handle = Some(handle);
+    let handler = Handler {
+        thread_tx,
+        handle,
+        _watcher: watcher,
+    };
+    (handler, rx)
+}