Implement MallocSizeOf for SmallVec (v1)

Author: nicoburns

.github/workflows/main.yml

@@ -48,6 +48,10 @@ jobs:
         if: matrix.toolchain != '1.36.0'
         run: cargo test --verbose --features serde
 
+      - name: Cargo test w/ malloc_size_of
+        if: matrix.toolchain != '1.36.0'
+        run: cargo test --verbose --features malloc_size_of
+
       - name: Cargo check w/o default features
         if: matrix.toolchain == 'nightly'
         run: cargo check --verbose --no-default-features

Cargo.toml

@@ -27,6 +27,7 @@ debugger_visualizer = []
 
 [dependencies]
 serde = { version = "1", optional = true, default-features = false }
+malloc_size_of = { version = "0.1", optional = true, default-features = false }
 arbitrary = { version = "1", optional = true }
 
 [dev_dependencies]

src/lib.rs

@@ -126,6 +126,9 @@ use core::ops::{self, Range, RangeBounds};
 use core::ptr::{self, NonNull};
 use core::slice::{self, SliceIndex};
 
+#[cfg(feature = "malloc_size_of")]
+use malloc_size_of::{MallocShallowSizeOf, MallocSizeOf, MallocSizeOfOps};
+
 #[cfg(feature = "serde")]
 use serde::{
     de::{Deserialize, Deserializer, SeqAccess, Visitor},
@@ -1971,6 +1974,32 @@ where
     }
 }
 
+#[cfg(feature = "malloc_size_of")]
+impl<A: Array> MallocShallowSizeOf for SmallVec<A> {
+    fn shallow_size_of(&self, ops: &mut MallocSizeOfOps) -> usize {
+        if self.spilled() {
+            unsafe { ops.malloc_size_of(self.as_ptr()) }
+        } else {
+            0
+        }
+    }
+}
+
+#[cfg(feature = "malloc_size_of")]
+impl<A> MallocSizeOf for SmallVec<A>
+where
+    A: Array,
+    A::Item: MallocSizeOf,
+{
+    fn size_of(&self, ops: &mut MallocSizeOfOps) -> usize {
+        let mut n = self.shallow_size_of(ops);
+        for elem in self.iter() {
+            n += elem.size_of(ops);
+        }
+        n
+    }
+}
+
 #[cfg(feature = "specialization")]
 trait SpecFrom<A: Array, S> {
     fn spec_from(slice: S) -> SmallVec<A>;