daemon: use smallvec for storing some data

Because we mostly store a small number of items, `smallvec` can actually
be very nice for us.

Author: LGFae

Cargo.lock

@@ -18,10 +18,11 @@ log = { version = "0.4", default-features = false, features = [
   "release_max_level_info",
   "std",
 ] }
-rustix = { version = "1.1", default-features = false, features = ["event"] }
+rustix = { version = "1.1", default-features = false, features = [ "event" ] }
 libc = "0.2"
 keyframe = "1.1"
 sd-notify = { version = "0.4" }
+smallvec  = { version = "1.15", default-features = false, features = [ "union" ] }
 
 [build-dependencies]
 waybackend-scanner = { version = "0.7", features = ["build-script"] }

daemon/Cargo.toml

@@ -1,4 +1,5 @@
 use log::error;
+use smallvec::SmallVec;
 use waybackend::{Waybackend, objman::ObjectManager};
 
 use std::time::{Duration, Instant};
@@ -15,7 +16,7 @@ mod transitions;
 use transitions::Effect;
 
 pub struct Animator {
-    pub wallpapers: Vec<WallpaperCell>,
+    pub wallpapers: SmallVec<[WallpaperCell; 2]>,
     now: Instant,
     animator: AnimatorKind,
 }
@@ -27,7 +28,7 @@ enum AnimatorKind {
 
 impl Animator {
     pub fn new(
-        mut wallpapers: Vec<WallpaperCell>,
+        mut wallpapers: SmallVec<[WallpaperCell; 2]>,
         transition: &ipc::Transition,
         img_req: ImgReq,
         animation: Option<ipc::Animation>,
@@ -157,7 +158,7 @@ impl Animation {
         &mut self,
         backend: &mut Waybackend,
         objman: &mut ObjectManager<WaylandObject>,
-        wallpapers: &mut Vec<WallpaperCell>,
+        wallpapers: &mut SmallVec<[WallpaperCell; 2]>,
         pixel_format: PixelFormat,
     ) {
         let Self {

daemon/src/animations.rs

@@ -14,6 +14,7 @@ use rustix::{
     fs::Timespec,
 };
 
+use smallvec::SmallVec;
 use wallpaper::WallpaperCell;
 
 use waybackend::{Global, objman, types::ObjectId};
@@ -58,7 +59,7 @@ struct Daemon {
     layer_shell: ObjectId,
     layer: Layer,
     pixel_format: PixelFormat,
-    wallpapers: Vec<WallpaperCell>,
+    wallpapers: SmallVec<[WallpaperCell; 2]>,
     animators: Vec<Animator>,
     namespace: String,
     use_cache: bool,
@@ -115,7 +116,7 @@ impl Daemon {
             layer_shell,
             layer: args.layer,
             pixel_format: args.format.unwrap_or(PixelFormat::Argb),
-            wallpapers: Vec::with_capacity(1),
+            wallpapers: SmallVec::new(),
             animators: Vec::with_capacity(1),
             namespace: args.namespace,
             use_cache: !args.no_cache,
@@ -224,7 +225,7 @@ impl Daemon {
             .collect()
     }
 
-    fn find_wallpapers_by_names(&self, names: &[MmappedStr]) -> Vec<WallpaperCell> {
+    fn find_wallpapers_by_names(&self, names: &[MmappedStr]) -> SmallVec<[WallpaperCell; 2]> {
         self.wallpapers
             .iter()
             .filter_map(|wallpaper| {
@@ -284,7 +285,7 @@ impl Daemon {
     }
 
     fn commit_pending_surface_changes(&mut self) {
-        let mut to_stop = Vec::with_capacity(self.wallpapers.len());
+        let mut to_stop = SmallVec::<[WallpaperCell; 2]>::with_capacity(self.wallpapers.len());
         for wallpaper in &self.wallpapers {
             if wallpaper.borrow_mut().commit_surface_changes(
                 &mut self.backend,

daemon/src/main.rs

@@ -1,4 +1,5 @@
 use common::{ipc::PixelFormat, mmap::Mmap};
+use smallvec::SmallVec;
 use waybackend::{Waybackend, objman::ObjectManager, types::ObjectId};
 
 use crate::wayland::{wl_shm, wl_shm_pool};
@@ -62,10 +63,10 @@ impl Buffer {
 pub struct BumpPool {
     pool_id: ObjectId,
     mmap: Mmap,
-    buffers: Vec<Buffer>,
+    buffers: SmallVec<[Buffer; 2]>,
     /// This for when resizes happen, where we cannot delete a buffer before it was released by the
     /// compositor, least undefined behavior happens
-    dead_buffers: Vec<ObjectId>,
+    dead_buffers: SmallVec<[ObjectId; 4]>,
     width: i32,
     height: i32,
     last_used_buffer: usize,
@@ -89,8 +90,8 @@ impl BumpPool {
         Self {
             pool_id,
             mmap,
-            buffers: Vec::with_capacity(2),
-            dead_buffers: Vec::with_capacity(1),
+            buffers: SmallVec::new(),
+            dead_buffers: SmallVec::new(),
             width,
             height,
             last_used_buffer: 0,