chore: Replace generational-arena with slotmap

Cargo.toml

@@ -51,6 +51,7 @@ wgpu = "0.19.3"
 egui = "0.26.2"
 clap = { version = "4.5.1", features = ["derive"] }
 anyhow = "1.0"
+slotmap = "1.0.7"
 
 [workspace.lints.rust]
 # Clippy nightly often adds new/buggy lints that we want to ignore.

core/Cargo.toml

@@ -17,7 +17,7 @@ bitstream-io = "2.2.0"
 flate2 = "1.0.28"
 fnv = "1.0.7"
 gc-arena = { package = "ruffle_gc_arena", path = "../ruffle_gc_arena" }
-generational-arena = "0.2.9"
+slotmap = { workspace = true }
 indexmap = "2.2.5"
 tracing = { workspace = true }
 ruffle_render = { path = "../render", features = ["tessellator"] }

core/src/backend/audio.rs

@@ -7,7 +7,7 @@ use crate::{
 };
 use downcast_rs::Downcast;
 use gc_arena::Collect;
-use generational_arena::{Arena, Index};
+use slotmap::{DefaultKey, Key, SlotMap};
 
 #[cfg(feature = "audio")]
 pub mod decoders;
@@ -35,8 +35,8 @@ mod decoders {
 use thiserror::Error;
 use web_time::Duration;
 
-pub type SoundHandle = Index;
-pub type SoundInstanceHandle = Index;
+pub type SoundHandle = DefaultKey;
+pub type SoundInstanceHandle = DefaultKey;
 pub type DecodeError = decoders::Error;
 
 #[derive(Eq, PartialEq, Clone, Copy, Debug)]
@@ -205,14 +205,14 @@ struct NullSound {
 
 /// Audio backend that ignores all audio.
 pub struct NullAudioBackend {
-    sounds: Arena<NullSound>,
+    sounds: SlotMap<SoundHandle, NullSound>,
     volume: f32,
 }
 
 impl NullAudioBackend {
     pub fn new() -> NullAudioBackend {
         NullAudioBackend {
-            sounds: Arena::new(),
+            sounds: SlotMap::new(),
             volume: 1.0,
         }
     }
@@ -259,23 +259,23 @@ impl AudioBackend for NullAudioBackend {
         _sound: SoundHandle,
         _sound_info: &swf::SoundInfo,
     ) -> Result<SoundInstanceHandle, DecodeError> {
-        Ok(SoundInstanceHandle::from_raw_parts(0, 0))
+        Ok(SoundInstanceHandle::null())
     }
 
     fn start_stream(
         &mut self,
         _clip_data: crate::tag_utils::SwfSlice,
         _handle: &swf::SoundStreamHead,
     ) -> Result<SoundInstanceHandle, DecodeError> {
-        Ok(SoundInstanceHandle::from_raw_parts(0, 0))
+        Ok(SoundInstanceHandle::null())
     }
 
     fn start_substream(
         &mut self,
         _stream_data: Substream,
         _handle: &SoundStreamInfo,
     ) -> Result<SoundInstanceHandle, DecodeError> {
-        Ok(SoundInstanceHandle::from_raw_parts(0, 0))
+        Ok(SoundInstanceHandle::null())
     }
 
     fn stop_sound(&mut self, _sound: SoundInstanceHandle) {}

core/src/backend/audio/mixer.rs

@@ -3,7 +3,7 @@ use super::{SoundHandle, SoundInstanceHandle, SoundStreamInfo, SoundTransform};
 use crate::backend::audio::{DecodeError, RegisterError};
 use crate::buffer::Substream;
 use crate::tag_utils::SwfSlice;
-use generational_arena::Arena;
+use slotmap::SlotMap;
 use std::io::Cursor;
 use std::sync::{Arc, Mutex, RwLock};
 use swf::AudioCompression;
@@ -54,10 +54,10 @@ impl CircBuf {
 // all sounds and mix the audio into an output buffer audio stream.
 pub struct AudioMixer {
     /// The currently registered sounds.
-    sounds: Arena<Sound>,
+    sounds: SlotMap<SoundHandle, Sound>,
 
     /// The list of actively playing sound instances.
-    sound_instances: Arc<Mutex<Arena<SoundInstance>>>,
+    sound_instances: Arc<Mutex<SlotMap<SoundInstanceHandle, SoundInstance>>>,
 
     /// The master volume of the audio from [0.0, 1.0].
     volume: Arc<RwLock<f32>>,
@@ -239,8 +239,8 @@ impl AudioMixer {
     /// Creates a new `AudioMixer` with the given number of channels and sample rate.
     pub fn new(num_output_channels: u8, output_sample_rate: u32) -> Self {
         Self {
-            sounds: Arena::new(),
-            sound_instances: Arc::new(Mutex::new(Arena::new())),
+            sounds: SlotMap::new(),
+            sound_instances: Arc::new(Mutex::new(SlotMap::new())),
             volume: Arc::new(RwLock::new(1.0)),
             num_output_channels,
             output_sample_rate,
@@ -428,7 +428,7 @@ impl AudioMixer {
     /// Refill the output buffer by stepping through all active sounds
     /// and mixing in their output.
     fn mix_audio<'a, T>(
-        sound_instances: &mut Arena<SoundInstance>,
+        sound_instances: &mut SlotMap<SoundInstanceHandle, SoundInstance>,
         volume: f32,
         num_channels: u8,
         mut output_buffer: &mut [T],
@@ -724,7 +724,7 @@ impl AudioMixer {
 /// to perform audio mixing on a different thread.
 pub struct AudioMixerProxy {
     /// The list of actively playing sound instances.
-    sound_instances: Arc<Mutex<Arena<SoundInstance>>>,
+    sound_instances: Arc<Mutex<SlotMap<SoundInstanceHandle, SoundInstance>>>,
 
     /// The master volume of the audio from [0.0, 1.0].
     volume: Arc<RwLock<f32>>,

core/src/loader.rs

@@ -32,8 +32,8 @@ use crate::vminterface::Instantiator;
 use crate::{avm2_stub_method, avm2_stub_method_context};
 use encoding_rs::UTF_8;
 use gc_arena::{Collect, GcCell};
-use generational_arena::{Arena, Index};
 use ruffle_render::utils::{determine_jpeg_tag_format, JpegTagFormat};
+use slotmap::{DefaultKey, SlotMap};
 use std::borrow::Borrow;
 use std::fmt;
 use std::sync::{Arc, Mutex, Weak};
@@ -42,7 +42,7 @@ use swf::read::{extract_swz, read_compression_type};
 use thiserror::Error;
 use url::{form_urlencoded, ParseError, Url};
 
-pub type Handle = Index;
+pub type Handle = DefaultKey;
 
 /// The depth of AVM1 movies that AVM2 loads.
 const LOADER_INSERTED_AVM1_DEPTH: i32 = -0xF000;
@@ -224,7 +224,7 @@ impl From<crate::avm1::Error<'_>> for Error {
 }
 
 /// Holds all in-progress loads for the player.
-pub struct LoadManager<'gc>(Arena<Loader<'gc>>);
+pub struct LoadManager<'gc>(SlotMap<Handle, Loader<'gc>>);
 
 unsafe impl<'gc> Collect for LoadManager<'gc> {
     fn trace(&self, cc: &gc_arena::Collection) {
@@ -237,7 +237,7 @@ unsafe impl<'gc> Collect for LoadManager<'gc> {
 impl<'gc> LoadManager<'gc> {
     /// Construct a new `LoadManager`.
     pub fn new() -> Self {
-        Self(Arena::new())
+        Self(SlotMap::new())
     }
 
     /// Add a new loader to the `LoadManager`.
@@ -355,15 +355,24 @@ impl<'gc> LoadManager<'gc> {
     ///
     /// This also removes all movie loaders that have completed.
     pub fn movie_clip_on_load(&mut self, queue: &mut ActionQueue<'gc>) {
-        let mut invalidated_loaders = vec![];
-
-        for (index, loader) in self.0.iter_mut().rev() {
-            if loader.movie_clip_loaded(queue) {
-                invalidated_loaders.push(index);
-            }
-        }
-
-        for index in invalidated_loaders {
+        // FIXME: This relies on the iteration order of the slotmap, which
+        // is not defined. The container should be replaced with something
+        // that preserves insertion order, such as `LinkedHashMap` -
+        // unfortunately that doesn't provide automatic key generation.
+        let mut loaders: Vec<_> = self.0.keys().collect();
+        // `SlotMap` doesn't provide reverse iteration, so reversing afterwards.
+        loaders.reverse();
+
+        // Removing the keys from `loaders` whose movie hasn't loaded yet.
+        loaders.retain(|handle| {
+            self.0
+                .get_mut(*handle)
+                .expect("valid key")
+                .movie_clip_loaded(queue)
+        });
+
+        // Cleaning up the loaders that are done.
+        for index in loaders {
             self.0.remove(index);
         }
     }
@@ -1692,7 +1701,7 @@ impl<'gc> Loader<'gc> {
     }
 
     /// Report a movie loader start event to script code.
-    fn movie_loader_start(handle: Index, uc: &mut UpdateContext<'_, 'gc>) -> Result<(), Error> {
+    fn movie_loader_start(handle: Handle, uc: &mut UpdateContext<'_, 'gc>) -> Result<(), Error> {
         let me = uc.load_manager.get_loader_mut(handle);
         if me.is_none() {
             return Err(Error::Cancelled);
@@ -2080,7 +2089,7 @@ impl<'gc> Loader<'gc> {
     ///
     /// The current and total length are always reported as compressed lengths.
     fn movie_loader_progress(
-        handle: Index,
+        handle: Handle,
         uc: &mut UpdateContext<'_, 'gc>,
         cur_len: usize,
         total_len: usize,
@@ -2146,7 +2155,7 @@ impl<'gc> Loader<'gc> {
 
     /// Report a movie loader completion to script code.
     fn movie_loader_complete(
-        handle: Index,
+        handle: Handle,
         uc: &mut UpdateContext<'_, 'gc>,
         dobj: Option<DisplayObject<'gc>>,
         status: u16,
@@ -2315,7 +2324,7 @@ impl<'gc> Loader<'gc> {
     /// This is an associated function because we cannot borrow both the update
     /// context and one of it's loaders.
     fn movie_loader_error(
-        handle: Index,
+        handle: Handle,
         uc: &mut UpdateContext<'_, 'gc>,
         msg: AvmString<'gc>,
         status: u16,

core/src/local_connection.rs

@@ -2,9 +2,9 @@ use crate::avm1::Object as Avm1Object;
 use crate::avm2::object::LocalConnectionObject;
 use crate::string::AvmString;
 use gc_arena::Collect;
-use generational_arena::{Arena, Index};
+use slotmap::{DefaultKey, SlotMap};
 
-pub type LocalConnectionHandle = Index;
+pub type LocalConnectionHandle = DefaultKey;
 
 #[derive(Collect)]
 #[collect(no_drop)]
@@ -41,7 +41,7 @@ impl<'gc> LocalConnection<'gc> {
 
 /// Manages the collection of local connections.
 pub struct LocalConnections<'gc> {
-    connections: Arena<LocalConnection<'gc>>,
+    connections: SlotMap<LocalConnectionHandle, LocalConnection<'gc>>,
 }
 
 unsafe impl<'gc> Collect for LocalConnections<'gc> {
@@ -55,7 +55,7 @@ unsafe impl<'gc> Collect for LocalConnections<'gc> {
 impl<'gc> LocalConnections<'gc> {
     pub fn empty() -> Self {
         Self {
-            connections: Arena::new(),
+            connections: SlotMap::new(),
         }
     }
 

core/src/net_connection.rs

@@ -10,12 +10,12 @@ use crate::Player;
 use flash_lso::packet::{Header, Message, Packet};
 use flash_lso::types::{AMFVersion, Value as AmfValue};
 use gc_arena::{Collect, DynamicRoot, Rootable};
-use generational_arena::{Arena, Index};
+use slotmap::{DefaultKey, SlotMap};
 use std::fmt::{Debug, Formatter};
 use std::rc::Rc;
 use std::sync::{Mutex, Weak};
 
-pub type NetConnectionHandle = Index;
+pub type NetConnectionHandle = DefaultKey;
 
 #[derive(Debug, Copy, Clone, Eq, PartialEq, Hash)]
 pub enum ResponderCallback {
@@ -76,7 +76,7 @@ impl<'gc> From<Avm2NetConnectionObject<'gc>> for NetConnectionObject<'gc> {
 
 /// Manages the collection of NetConnections.
 pub struct NetConnections<'gc> {
-    connections: Arena<NetConnection<'gc>>,
+    connections: SlotMap<NetConnectionHandle, NetConnection<'gc>>,
 }
 
 unsafe impl<'gc> Collect for NetConnections<'gc> {
@@ -90,7 +90,7 @@ unsafe impl<'gc> Collect for NetConnections<'gc> {
 impl<'gc> Default for NetConnections<'gc> {
     fn default() -> Self {
         Self {
-            connections: Arena::new(),
+            connections: SlotMap::new(),
         }
     }
 }