From e4083288e674fb0fc4b6bb9ca3bfd3cc1c167d96 Mon Sep 17 00:00:00 2001
From: Erica Z <zerica@callcc.eu>
Date: Sun, 3 Nov 2024 15:06:11 +0100
Subject: [PATCH] now safer

---
 src/mpv/handle.rs | 17 +++++++++++++++++
 src/playbin2.rs   |  4 +---
 2 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/src/mpv/handle.rs b/src/mpv/handle.rs
index 92e9d42..4407443 100644
--- a/src/mpv/handle.rs
+++ b/src/mpv/handle.rs
@@ -13,6 +13,8 @@ pub struct Handle {
     inner: NonNull<ffi::mpv_handle>,
     wakeup: Pin<Box<Event>>, // the wakeup callback holds a pointer to this
     wait_event_cell: RefCell<()>,
+
+    pending_hooks: RefCell<Vec<u64>>,
 }
 
 // The client API is generally fully thread-safe, unless otherwise noted.
@@ -67,6 +69,8 @@ impl Handle {
             inner,
             wakeup,
             wait_event_cell: RefCell::new(()),
+
+            pending_hooks: RefCell::new(vec![]),
         }
     }
 
@@ -141,6 +145,18 @@ impl Handle {
         Error::from_return_code(unsafe { ffi::mpv_hook_continue(self.inner.as_ptr(), id) })
     }
 
+    pub fn continue_hook(&self, id: u64) -> Result<(), Error> {
+        let mut pending_hooks = self.pending_hooks.borrow_mut();
+        for (i, pending_id) in pending_hooks.iter().enumerate() {
+            if *pending_id == id {
+                pending_hooks.swap_remove(i);
+                return unsafe { self.continue_hook_unchecked(id) };
+            }
+        }
+
+        panic!("invalid hook id")
+    }
+
     // should take listener before we drain the event queue, so we don't miss any notifications
     pub fn wakeup_listener(&self) -> EventListener {
         self.wakeup.listen()
@@ -219,6 +235,7 @@ impl Handle {
 
             ffi::mpv_event_id_MPV_EVENT_HOOK => {
                 let data = unsafe { &*(event.data as *mut ffi::mpv_event_hook) };
+                self.pending_hooks.borrow_mut().push(data.id);
                 Some(MpvEvent::Hook(HookEvent {
                     reply_userdata: event.reply_userdata,
                     name: unsafe { CStr::from_ptr(data.name) }
diff --git a/src/playbin2.rs b/src/playbin2.rs
index e149d96..ede297c 100644
--- a/src/playbin2.rs
+++ b/src/playbin2.rs
@@ -179,9 +179,7 @@ where
                     assert_eq!(&event.name, "on_before_start_file");
                     // just use this as a barrier
                     println!("on_before_start_file triggered");
-                    unsafe {
-                        self.mpv.continue_hook_unchecked(event.id).unwrap();
-                    }
+                    self.mpv.continue_hook(event.id).unwrap();
                 }
 
                 _ => unreachable!(),