feat: VecDeque (#11)

.github/workflows/ci.yml

@@ -59,3 +59,35 @@ jobs:
       # Test
       - name: Test
         run: cargo test ${{ matrix.profile }} ${{ matrix.features }}
+
+  miri_test:
+    name: Miri Test
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v3
+      - name: Set up Rust
+        uses: actions-rs/toolchain@v1
+        with:
+          profile: minimal
+          toolchain: nightly
+      - name: Install miri
+        run: rustup +nightly component add miri
+      - name: Run miri tests
+        run: cargo miri test
+
+  asan_test:
+    name: Address Sanitizer Test
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v3
+      - name: Set up Rust
+        uses: actions-rs/toolchain@v1
+        with:
+          profile: minimal
+          toolchain: nightly
+      - name: Install miri
+        run: rustup +nightly component add miri
+      - name: Run ASan tests
+        run: RUSTFLAGS="-Z sanitizer=address" cargo test

src/lib.rs

@@ -1,4 +1,4 @@
-#![cfg_attr(feature = "no_std", no_std)]
+#![cfg_attr(not(test), cfg_attr(feature = "no_std", no_std))]
 #![feature(allocator_api)]
 #![cfg_attr(not(doctest), doc = include_str!("../README.md"))]
 
@@ -8,3 +8,11 @@ extern crate core;
 pub mod claim;
 pub mod try_clone;
 pub mod vec;
+pub mod vec_deque;
+
+#[cfg(test)]
+pub(crate) mod testing;
+
+#[cfg(test)]
+#[global_allocator]
+static GLOBAL: testing::GlobalAllocTestGuardAllocator = testing::GlobalAllocTestGuardAllocator;

src/testing.rs

@@ -0,0 +1,199 @@
+use crate::claim::Claim;
+use alloc::sync::Arc;
+use core::ptr::NonNull;
+use core::sync::atomic::{AtomicUsize, Ordering};
+use std::alloc::{AllocError, Allocator, Global, GlobalAlloc, Layout, System};
+
+thread_local! {
+    static GLOBAL_ALLOC_ALLOWED: std::cell::RefCell<bool> = const { std::cell::RefCell::new(true) };
+}
+
+struct NoPubCtor;
+
+/// A guard that temporarily error if a test performs global allocation in the current thread.
+pub struct NoGlobalAllocGuard(NoPubCtor);
+
+impl NoGlobalAllocGuard {
+    pub fn new() -> Self {
+        GLOBAL_ALLOC_ALLOWED.with(|alloc_allowed| {
+            let mut alloc_allowed = alloc_allowed.borrow_mut();
+            if !*alloc_allowed {
+                panic!("NoGlobalAllocGuard is not re-entrant.");
+            }
+            *alloc_allowed = false; // Disable global allocation
+        });
+
+        Self(NoPubCtor)
+    }
+}
+
+impl Drop for NoGlobalAllocGuard {
+    fn drop(&mut self) {
+        GLOBAL_ALLOC_ALLOWED.with(|alloc_allowed| {
+            let mut alloc_allowed = alloc_allowed.borrow_mut();
+            *alloc_allowed = true;
+        });
+    }
+}
+
+pub struct AllowGlobalAllocGuard {
+    was_allowed: bool,
+}
+
+impl AllowGlobalAllocGuard {
+    pub fn new() -> Self {
+        let was_allowed = GLOBAL_ALLOC_ALLOWED.with(|alloc_allowed| {
+            let was_allowed = *alloc_allowed.borrow();
+            if !was_allowed {
+                let mut alloc_allowed = alloc_allowed.borrow_mut();
+                *alloc_allowed = true;
+            }
+            was_allowed
+        });
+
+        Self { was_allowed }
+    }
+}
+
+impl Drop for AllowGlobalAllocGuard {
+    fn drop(&mut self) {
+        GLOBAL_ALLOC_ALLOWED.with(|alloc_allowed| {
+            let mut alloc_allowed = alloc_allowed.borrow_mut();
+            *alloc_allowed = self.was_allowed;
+        });
+    }
+}
+
+/// Enables the `NoGlobalAllocGuard` by acting as a global allocator.
+pub struct GlobalAllocTestGuardAllocator;
+
+impl GlobalAllocTestGuardAllocator {
+    fn is_allowed(&self) -> bool {
+        GLOBAL_ALLOC_ALLOWED.with(|alloc_allowed| {
+            *alloc_allowed.borrow() // Check if allocation is allowed for the current thread
+        })
+    }
+
+    fn guard(&self) {
+        if !self.is_allowed() {
+            panic!("Caught unexpected global allocation with the NoGlobalAllocGuard. Run tests under debugger.");
+        }
+    }
+}
+
+unsafe impl GlobalAlloc for GlobalAllocTestGuardAllocator {
+    unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
+        self.guard();
+        System.alloc(layout)
+    }
+
+    unsafe fn dealloc(&self, ptr: *mut u8, layout: Layout) {
+        self.guard();
+        System.dealloc(ptr, layout)
+    }
+
+    unsafe fn alloc_zeroed(&self, layout: Layout) -> *mut u8 {
+        self.guard();
+        System.alloc_zeroed(layout)
+    }
+
+    unsafe fn realloc(&self, ptr: *mut u8, layout: Layout, new_size: usize) -> *mut u8 {
+        self.guard();
+        System.realloc(ptr, layout, new_size)
+    }
+}
+
+#[derive(Clone)]
+pub struct WatermarkAllocator {
+    watermark: usize,
+    in_use: Option<Arc<AtomicUsize>>,
+}
+
+impl Drop for WatermarkAllocator {
+    fn drop(&mut self) {
+        let in_use = self.in_use.take().unwrap();
+        let _g = AllowGlobalAllocGuard::new();
+        drop(in_use);
+    }
+}
+
+impl WatermarkAllocator {
+    pub fn new(watermark: usize) -> Self {
+        let in_use = Some({
+            let _g = AllowGlobalAllocGuard::new();
+            AtomicUsize::new(0).into()
+        });
+        Self { watermark, in_use }
+    }
+
+    pub fn in_use(&self) -> usize {
+        self.in_use.as_ref().unwrap().load(Ordering::SeqCst)
+    }
+}
+
+impl Claim for WatermarkAllocator {}
+
+unsafe impl Allocator for WatermarkAllocator {
+    fn allocate(&self, layout: Layout) -> Result<NonNull<[u8]>, AllocError> {
+        let current_in_use = self.in_use.as_ref().unwrap().load(Ordering::SeqCst);
+        let new_in_use = current_in_use + layout.size();
+        if new_in_use > self.watermark {
+            return Err(AllocError);
+        }
+        let allocated = {
+            let _g = AllowGlobalAllocGuard::new();
+            Global.allocate(layout)?
+        };
+        let true_new_in_use = self
+            .in_use
+            .as_ref()
+            .unwrap()
+            .fetch_add(allocated.len(), Ordering::SeqCst);
+        unsafe {
+            if true_new_in_use > self.watermark {
+                let ptr = allocated.as_ptr() as *mut u8;
+                let to_dealloc = NonNull::new_unchecked(ptr);
+                {
+                    let _g = AllowGlobalAllocGuard::new();
+                    Global.deallocate(to_dealloc, layout);
+                }
+                Err(AllocError)
+            } else {
+                Ok(allocated)
+            }
+        }
+    }
+
+    unsafe fn deallocate(&self, ptr: NonNull<u8>, layout: Layout) {
+        let _g = AllowGlobalAllocGuard::new();
+        Global.deallocate(ptr, layout);
+        self.in_use
+            .as_ref()
+            .unwrap()
+            .fetch_sub(layout.size(), Ordering::SeqCst);
+    }
+}
+
+/// A second watermark allocator. This is just to test cases where we need generic types
+/// to interoperate, even when their allocator differs. E.g. `lhs: Vec<T, A1> == rhs: Vec<T, A2>`.
+#[derive(Clone)]
+pub struct WatermarkAllocator2(WatermarkAllocator);
+
+impl WatermarkAllocator2 {
+    pub fn new(watermark: usize) -> Self {
+        let inner = WatermarkAllocator::new(watermark);
+        Self(inner)
+    }
+}
+
+impl Claim for WatermarkAllocator2 {}
+
+unsafe impl Allocator for WatermarkAllocator2 {
+    fn allocate(&self, layout: Layout) -> Result<NonNull<[u8]>, AllocError> {
+        self.0.allocate(layout)
+    }
+
+    unsafe fn deallocate(&self, ptr: NonNull<u8>, layout: Layout) {
+        self.0.deallocate(ptr, layout)
+    }
+}