From 40db5b1b18c5f71cad5fdc57e9a60202619afed8 Mon Sep 17 00:00:00 2001
From: Erica Z <zerica@callcc.eu>
Date: Sun, 3 Nov 2024 11:57:55 +0100
Subject: [PATCH] trying own signal handler impl

---
 src/main.rs   |  3 ++
 src/signal.rs | 87 +++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 90 insertions(+)
 create mode 100644 src/signal.rs

diff --git a/src/main.rs b/src/main.rs
index 4c5511f..7c64e3b 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -19,6 +19,9 @@ pub mod subsonic_vala;
 
 mod playbin2;
 
+mod signal;
+pub use signal::{Signal, SignalHandler};
+
 use gettextrs::{bind_textdomain_codeset, bindtextdomain, setlocale, textdomain, LocaleCategory};
 use gtk::prelude::*;
 use gtk::{gio, glib};
diff --git a/src/signal.rs b/src/signal.rs
new file mode 100644
index 0000000..7691e1c
--- /dev/null
+++ b/src/signal.rs
@@ -0,0 +1,87 @@
+use std::cell::{Cell, RefCell};
+use std::rc::{Rc, Weak};
+
+#[derive(Default)]
+pub struct Signal<T> {
+    handlers: RefCell<Vec<Box<dyn FnMut(T) -> bool>>>,
+    just_connected: RefCell<Vec<Box<dyn FnMut(T) -> bool>>>,
+}
+
+pub struct SignalHandler(Weak<Cell<bool>>);
+
+impl SignalHandler {
+    pub fn disconnect(self) -> bool {
+        match self.0.upgrade() {
+            None => false,
+            Some(cell) => {
+                cell.set(true);
+                true
+            }
+        }
+    }
+}
+
+impl<T> Signal<T> {
+    fn connect_impl(&self, f: impl FnMut(T) -> bool + 'static) {
+        self.just_connected.borrow_mut().push(Box::new(f));
+    }
+
+    pub fn connect(&self, mut f: impl FnMut(T) -> bool + 'static) -> SignalHandler {
+        let disconnect = Rc::new(Cell::new(false));
+        let disconnect_weak = Rc::downgrade(&disconnect);
+
+        self.connect_impl(move |t| match disconnect.get() {
+            false => false,
+            true => {
+                f(t);
+                true
+            }
+        });
+
+        SignalHandler(disconnect_weak)
+    }
+
+    pub fn connect_listener<L: 'static>(
+        &self,
+        listener: &Rc<L>,
+        mut f: impl FnMut(Rc<L>, T) -> bool + 'static,
+    ) -> SignalHandler {
+        let listener = Rc::downgrade(listener);
+
+        self.connect(move |t| match listener.upgrade() {
+            None => false,
+            Some(listener) => f(listener, t),
+        })
+    }
+}
+
+impl<T> Signal<T>
+where
+    T: Clone,
+{
+    pub fn emit(&self, t: T) {
+        let mut handlers = self
+            .handlers
+            .try_borrow_mut()
+            .expect("tried to re-emit signal during emission");
+        handlers.append(self.just_connected.borrow_mut().as_mut());
+
+        let mut i = 0;
+        let mut skip = 0;
+        loop {
+            if handlers[i + skip](t.clone()) {
+                i += 1;
+            } else {
+                skip += 1;
+            }
+
+            if i + skip == handlers.len() {
+                break;
+            }
+
+            handlers.swap(i, i + skip);
+        }
+
+        handlers.truncate(i);
+    }
+}