From 024d84192727b3c5bfbc40247559ce9af4d92d5d Mon Sep 17 00:00:00 2001
From: Haled Odat <halidodat@gmail.com>
Date: Thu, 30 Mar 2023 00:27:55 +0200
Subject: [PATCH] Implement Trace and Finalize on ThinVec

---
 Cargo.lock                            |  1 +
 boa_engine/Cargo.toml                 |  2 +-
 boa_engine/src/object/property_map.rs | 15 +--------------
 boa_gc/Cargo.toml                     |  6 ++++++
 boa_gc/src/trace.rs                   | 13 +++++++++++++
 5 files changed, 22 insertions(+), 15 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 7a5664ecc33..9d39c523fc0 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -398,6 +398,7 @@ version = "0.16.0"
 dependencies = [
  "boa_macros",
  "boa_profiler",
+ "thin-vec",
 ]
 
 [[package]]
diff --git a/boa_engine/Cargo.toml b/boa_engine/Cargo.toml
index aca72c6d911..93bffb2da8c 100644
--- a/boa_engine/Cargo.toml
+++ b/boa_engine/Cargo.toml
@@ -41,7 +41,7 @@ console = []
 
 [dependencies]
 boa_interner.workspace = true
-boa_gc.workspace = true
+boa_gc = { workspace = true, features = [ "thinvec" ] }
 boa_profiler.workspace = true
 boa_macros.workspace = true
 boa_ast.workspace = true
diff --git a/boa_engine/src/object/property_map.rs b/boa_engine/src/object/property_map.rs
index 32eb5ca475e..d9923f8ef19 100644
--- a/boa_engine/src/object/property_map.rs
+++ b/boa_engine/src/object/property_map.rs
@@ -36,7 +36,7 @@ unsafe impl<K: Trace> Trace for OrderedHashMap<K> {
 /// - `Sparse` Storage
 ///
 /// By default it is dense storage.
-#[derive(Debug, Finalize)]
+#[derive(Debug, Trace, Finalize)]
 enum IndexedProperties {
     /// Dense storage holds a contiguous array of properties where the index in the array is the key of the property.
     /// These are known to be data descriptors with a value field, writable field set to `true`, configurable field set to `true`, enumerable field set to `true`.
@@ -55,19 +55,6 @@ enum IndexedProperties {
     Sparse(Box<FxHashMap<u32, PropertyDescriptor>>),
 }
 
-unsafe impl Trace for IndexedProperties {
-    custom_trace!(this, {
-        match this {
-            Self::Dense(vec) => {
-                for elem in vec.iter() {
-                    mark(elem);
-                }
-            }
-            Self::Sparse(map) => mark(map),
-        }
-    });
-}
-
 impl Default for IndexedProperties {
     #[inline]
     fn default() -> Self {
diff --git a/boa_gc/Cargo.toml b/boa_gc/Cargo.toml
index 39f1afa64c1..74565960e09 100644
--- a/boa_gc/Cargo.toml
+++ b/boa_gc/Cargo.toml
@@ -10,6 +10,12 @@ license.workspace = true
 repository.workspace = true
 rust-version.workspace = true
 
+[features]
+# Enable default implementatio of trace and finalize thin-vec crate
+thinvec = ["thin-vec"]
+
 [dependencies]
 boa_profiler.workspace = true
 boa_macros.workspace = true
+
+thin-vec = { version = "0.2.12", optional = true }
\ No newline at end of file
diff --git a/boa_gc/src/trace.rs b/boa_gc/src/trace.rs
index f839ba7b79f..464cd989d66 100644
--- a/boa_gc/src/trace.rs
+++ b/boa_gc/src/trace.rs
@@ -308,6 +308,19 @@ unsafe impl<T: Trace> Trace for Vec<T> {
     });
 }
 
+#[cfg(feature = "thin-vec")]
+impl<T: Trace> Finalize for thin_vec::ThinVec<T> {}
+
+#[cfg(feature = "thin-vec")]
+// SAFETY: All the inner elements of the `Vec` are correctly marked.
+unsafe impl<T: Trace> Trace for thin_vec::ThinVec<T> {
+    custom_trace!(this, {
+        for e in this {
+            mark(e);
+        }
+    });
+}
+
 impl<T: Trace> Finalize for Option<T> {}
 // SAFETY: The inner value of the `Option` is correctly marked.
 unsafe impl<T: Trace> Trace for Option<T> {