Implement MallocSizeOf for thin-vec

.github/workflows/rust.yml

@@ -31,6 +31,8 @@ jobs:
     - uses: actions/checkout@v2
     - name: Build
       run: cargo build --verbose
+    - name: Build (malloc_size_of)
+      run: cargo build --features=malloc_size_of --verbose
     - name: Run tests
       run: cargo test --verbose
     - name: Run tests

Cargo.toml

@@ -1,7 +1,7 @@
 [package]
 edition = "2018"
 name = "thin-vec"
-version = "0.2.13"
+version = "0.2.14"
 authors = ["Aria Beingessner <[email protected]>"]
 description = "A vec that takes up less space on the stack"
 license = "MIT/Apache-2.0"
@@ -20,7 +20,11 @@ std = []
 gecko-ffi = []
 
 [dependencies]
-serde = {version = "1.0", optional = true}
+serde = { version = "1.0", optional = true }
+malloc_size_of = { version = "0.1", default-features = false, optional = true }
 
 [dev-dependencies]
 serde_test = "1.0"
+
+[lints.rust]
+unexpected_cfgs = { level = "warn", check-cfg = ['cfg(no_global_oom_handling)'] }

RELEASES.md

@@ -1,3 +1,6 @@
+# Version 0.2.14 (2025-02-19)
+* Add "malloc_size_of" feature for heap size measurement support
+
 # Version 0.2.13 (2023-12-02)
 
 * add default-on "std" feature for no_std support

src/lib.rs

@@ -163,6 +163,9 @@ use core::{fmt, mem, ptr, slice};
 
 use impl_details::*;
 
+#[cfg(feature = "malloc_size_of")]
+use malloc_size_of::{MallocShallowSizeOf, MallocSizeOf, MallocSizeOfOps};
+
 // modules: a simple way to cfg a whole bunch of impl details at once
 
 #[cfg(not(feature = "gecko-ffi"))]
@@ -1873,6 +1876,33 @@ impl<'de, T: serde::Deserialize<'de>> serde::Deserialize<'de> for ThinVec<T> {
     }
 }
 
+#[cfg(feature = "malloc_size_of")]
+impl<T> MallocShallowSizeOf for ThinVec<T> {
+    fn shallow_size_of(&self, ops: &mut MallocSizeOfOps) -> usize {
+        if self.capacity() == 0 {
+            // If it's the singleton we might not be a heap pointer.
+            return 0;
+        }
+
+        assert_eq!(
+            std::mem::size_of::<Self>(),
+            std::mem::size_of::<*const ()>()
+        );
+        unsafe { ops.malloc_size_of(*(self as *const Self as *const *const ())) }
+    }
+}
+
+#[cfg(feature = "malloc_size_of")]
+impl<T: MallocSizeOf> MallocSizeOf for ThinVec<T> {
+    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
+    }
+}
+
 macro_rules! array_impls {
     ($($N:expr)*) => {$(
         impl<A, B> PartialEq<[B; $N]> for ThinVec<A> where A: PartialEq<B> {