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Diffstat (limited to 'third_party/rust/thin-vec/src/lib.rs')
| -rw-r--r-- | third_party/rust/thin-vec/src/lib.rs | 4288 |
1 files changed, 4288 insertions, 0 deletions
diff --git a/third_party/rust/thin-vec/src/lib.rs b/third_party/rust/thin-vec/src/lib.rs new file mode 100644 index 0000000000..ea24aed2e0 --- /dev/null +++ b/third_party/rust/thin-vec/src/lib.rs @@ -0,0 +1,4288 @@ +#![deny(missing_docs)] + +//! `ThinVec` is exactly the same as `Vec`, except that it stores its `len` and `capacity` in the buffer +//! it allocates. +//! +//! This makes the memory footprint of ThinVecs lower; notably in cases where space is reserved for +//! a non-existence `ThinVec<T>`. So `Vec<ThinVec<T>>` and `Option<ThinVec<T>>::None` will waste less +//! space. Being pointer-sized also means it can be passed/stored in registers. +//! +//! Of course, any actually constructed `ThinVec` will theoretically have a bigger allocation, but +//! the fuzzy nature of allocators means that might not actually be the case. +//! +//! Properties of `Vec` that are preserved: +//! * `ThinVec::new()` doesn't allocate (it points to a statically allocated singleton) +//! * reallocation can be done in place +//! * `size_of::<ThinVec<T>>()` == `size_of::<Option<ThinVec<T>>>()` +//! +//! Properties of `Vec` that aren't preserved: +//! * `ThinVec<T>` can't ever be zero-cost roundtripped to a `Box<[T]>`, `String`, or `*mut T` +//! * `from_raw_parts` doesn't exist +//! * `ThinVec` currently doesn't bother to not-allocate for Zero Sized Types (e.g. `ThinVec<()>`), +//! but it could be done if someone cared enough to implement it. +//! +//! +//! +//! # Gecko FFI +//! +//! If you enable the gecko-ffi feature, `ThinVec` will verbatim bridge with the nsTArray type in +//! Gecko (Firefox). That is, `ThinVec` and nsTArray have identical layouts *but not ABIs*, +//! so nsTArrays/ThinVecs an be natively manipulated by C++ and Rust, and ownership can be +//! transferred across the FFI boundary (**IF YOU ARE CAREFUL, SEE BELOW!!**). +//! +//! While this feature is handy, it is also inherently dangerous to use because Rust and C++ do not +//! know about each other. Specifically, this can be an issue with non-POD types (types which +//! have destructors, move constructors, or are `!Copy`). +//! +//! ## Do Not Pass By Value +//! +//! The biggest thing to keep in mind is that **FFI functions cannot pass ThinVec/nsTArray +//! by-value**. That is, these are busted APIs: +//! +//! ```rust,ignore +//! // BAD WRONG +//! extern fn process_data(data: ThinVec<u32>) { ... } +//! // BAD WRONG +//! extern fn get_data() -> ThinVec<u32> { ... } +//! ``` +//! +//! You must instead pass by-reference: +//! +//! ```rust +//! # use thin_vec::*; +//! # use std::mem; +//! +//! // Read-only access, ok! +//! extern fn process_data(data: &ThinVec<u32>) { +//! for val in data { +//! println!("{}", val); +//! } +//! } +//! +//! // Replace with empty instance to take ownership, ok! +//! extern fn consume_data(data: &mut ThinVec<u32>) { +//! let owned = mem::replace(data, ThinVec::new()); +//! mem::drop(owned); +//! } +//! +//! // Mutate input, ok! +//! extern fn add_data(dataset: &mut ThinVec<u32>) { +//! dataset.push(37); +//! dataset.push(12); +//! } +//! +//! // Return via out-param, usually ok! +//! // +//! // WARNING: output must be initialized! (Empty nsTArrays are free, so just do it!) +//! extern fn get_data(output: &mut ThinVec<u32>) { +//! *output = thin_vec![1, 2, 3, 4, 5]; +//! } +//! ``` +//! +//! Ignorable Explanation For Those Who Really Want To Know Why: +//! +//! > The fundamental issue is that Rust and C++ can't currently communicate about destructors, and +//! > the semantics of C++ require destructors of function arguments to be run when the function +//! > returns. Whether the callee or caller is responsible for this is also platform-specific, so +//! > trying to hack around it manually would be messy. +//! > +//! > Also a type having a destructor changes its C++ ABI, because that type must actually exist +//! > in memory (unlike a trivial struct, which is often passed in registers). We don't currently +//! > have a way to communicate to Rust that this is happening, so even if we worked out the +//! > destructor issue with say, MaybeUninit, it would still be a non-starter without some RFCs +//! > to add explicit rustc support. +//! > +//! > Realistically, the best answer here is to have a "heavier" bindgen that can secretly +//! > generate FFI glue so we can pass things "by value" and have it generate by-reference code +//! > behind our back (like the cxx crate does). This would muddy up debugging/searchfox though. +//! +//! ## Types Should Be Trivially Relocatable +//! +//! Types in Rust are always trivially relocatable (unless suitably borrowed/[pinned][]/hidden). +//! This means all Rust types are legal to relocate with a bitwise copy, you cannot provide +//! copy or move constructors to execute when this happens, and the old location won't have its +//! destructor run. This will cause problems for types which have a significant location +//! (types that intrusively point into themselves or have their location registered with a service). +//! +//! While relocations are generally predictable if you're very careful, **you should avoid using +//! types with significant locations with Rust FFI**. +//! +//! Specifically, `ThinVec` will trivially relocate its contents whenever it needs to reallocate its +//! buffer to change its capacity. This is the default reallocation strategy for nsTArray, and is +//! suitable for the vast majority of types. Just be aware of this limitation! +//! +//! ## Auto Arrays Are Dangerous +//! +//! `ThinVec` has *some* support for handling auto arrays which store their buffer on the stack, +//! but this isn't well tested. +//! +//! Regardless of how much support we provide, Rust won't be aware of the buffer's limited lifetime, +//! so standard auto array safety caveats apply about returning/storing them! `ThinVec` won't ever +//! produce an auto array on its own, so this is only an issue for transferring an nsTArray into +//! Rust. +//! +//! ## Other Issues +//! +//! Standard FFI caveats also apply: +//! +//! * Rust is more strict about POD types being initialized (use MaybeUninit if you must) +//! * `ThinVec<T>` has no idea if the C++ version of `T` has move/copy/assign/delete overloads +//! * `nsTArray<T>` has no idea if the Rust version of `T` has a Drop/Clone impl +//! * C++ can do all sorts of unsound things that Rust can't catch +//! * C++ and Rust don't agree on how zero-sized/empty types should be handled +//! +//! The gecko-ffi feature will not work if you aren't linking with code that has nsTArray +//! defined. Specifically, we must share the symbol for nsTArray's empty singleton. You will get +//! linking errors if that isn't defined. +//! +//! The gecko-ffi feature also limits `ThinVec` to the legacy behaviors of nsTArray. Most notably, +//! nsTArray has a maximum capacity of i32::MAX (~2.1 billion items). Probably not an issue. +//! Probably. +//! +//! [pinned]: https://doc.rust-lang.org/std/pin/index.html + +#![allow(clippy::comparison_chain, clippy::missing_safety_doc)] + +use std::alloc::*; +use std::borrow::*; +use std::cmp::*; +use std::convert::TryFrom; +use std::convert::TryInto; +use std::hash::*; +use std::iter::FromIterator; +use std::marker::PhantomData; +use std::ops::Bound; +use std::ops::{Deref, DerefMut, RangeBounds}; +use std::ptr::NonNull; +use std::slice::IterMut; +use std::{fmt, io, mem, ptr, slice}; + +use impl_details::*; + +// modules: a simple way to cfg a whole bunch of impl details at once + +#[cfg(not(feature = "gecko-ffi"))] +mod impl_details { + pub type SizeType = usize; + pub const MAX_CAP: usize = !0; + + #[inline(always)] + pub fn assert_size(x: usize) -> SizeType { + x + } +} + +#[cfg(feature = "gecko-ffi")] +mod impl_details { + // Support for briding a gecko nsTArray verbatim into a ThinVec. + // + // `ThinVec` can't see copy/move/delete implementations + // from C++ + // + // The actual layout of an nsTArray is: + // + // ```cpp + // struct { + // uint32_t mLength; + // uint32_t mCapacity: 31; + // uint32_t mIsAutoArray: 1; + // } + // ``` + // + // Rust doesn't natively support bit-fields, so we manually mask + // and shift the bit. When the "auto" bit is set, the header and buffer + // are actually on the stack, meaning the `ThinVec` pointer-to-header + // is essentially an "owned borrow", and therefore dangerous to handle. + // There are no safety guards for this situation. + // + // On little-endian platforms, the auto bit will be the high-bit of + // our capacity u32. On big-endian platforms, it will be the low bit. + // Hence we need some platform-specific CFGs for the necessary masking/shifting. + // + // `ThinVec` won't ever construct an auto array. They only happen when + // bridging from C++. This means we don't need to ever set/preserve the bit. + // We just need to be able to read and handle it if it happens to be there. + // + // Handling the auto bit mostly just means not freeing/reallocating the buffer. + + pub type SizeType = u32; + + pub const MAX_CAP: usize = i32::max_value() as usize; + + // Little endian: the auto bit is the high bit, and the capacity is + // verbatim. So we just need to mask off the high bit. Note that + // this masking is unnecessary when packing, because assert_size + // guards against the high bit being set. + #[cfg(target_endian = "little")] + pub fn pack_capacity(cap: SizeType) -> SizeType { + cap as SizeType + } + #[cfg(target_endian = "little")] + pub fn unpack_capacity(cap: SizeType) -> usize { + (cap as usize) & !(1 << 31) + } + #[cfg(target_endian = "little")] + pub fn is_auto(cap: SizeType) -> bool { + (cap & (1 << 31)) != 0 + } + + // Big endian: the auto bit is the low bit, and the capacity is + // shifted up one bit. Masking out the auto bit is unnecessary, + // as rust shifts always shift in 0's for unsigned integers. + #[cfg(target_endian = "big")] + pub fn pack_capacity(cap: SizeType) -> SizeType { + (cap as SizeType) << 1 + } + #[cfg(target_endian = "big")] + pub fn unpack_capacity(cap: SizeType) -> usize { + (cap >> 1) as usize + } + #[cfg(target_endian = "big")] + pub fn is_auto(cap: SizeType) -> bool { + (cap & 1) != 0 + } + + #[inline] + pub fn assert_size(x: usize) -> SizeType { + if x > MAX_CAP as usize { + panic!("nsTArray size may not exceed the capacity of a 32-bit sized int"); + } + x as SizeType + } +} + +// The header of a ThinVec. +// +// The _cap can be a bitfield, so use accessors to avoid trouble. +// +// In "real" gecko-ffi mode, the empty singleton will be aligned +// to 8 by gecko. But in tests we have to provide the singleton +// ourselves, and Rust makes it hard to "just" align a static. +// To avoid messing around with a wrapper type around the +// singleton *just* for tests, we just force all headers to be +// aligned to 8 in this weird "zombie" gecko mode. +// +// This shouldn't affect runtime layout (padding), but it will +// result in us asking the allocator to needlessly overalign +// non-empty ThinVecs containing align < 8 types in +// zombie-mode, but not in "real" geck-ffi mode. Minor. +#[cfg_attr(all(feature = "gecko-ffi", any(test, miri)), repr(align(8)))] +#[repr(C)] +struct Header { + _len: SizeType, + _cap: SizeType, +} + +impl Header { + #[inline] + #[allow(clippy::unnecessary_cast)] + fn len(&self) -> usize { + self._len as usize + } + + #[inline] + fn set_len(&mut self, len: usize) { + self._len = assert_size(len); + } +} + +#[cfg(feature = "gecko-ffi")] +impl Header { + fn cap(&self) -> usize { + unpack_capacity(self._cap) + } + + fn set_cap(&mut self, cap: usize) { + // debug check that our packing is working + debug_assert_eq!(unpack_capacity(pack_capacity(cap as SizeType)), cap); + // FIXME: this assert is busted because it reads uninit memory + // debug_assert!(!self.uses_stack_allocated_buffer()); + + // NOTE: this always stores a cleared auto bit, because set_cap + // is only invoked by Rust, and Rust doesn't create auto arrays. + self._cap = pack_capacity(assert_size(cap)); + } + + fn uses_stack_allocated_buffer(&self) -> bool { + is_auto(self._cap) + } +} + +#[cfg(not(feature = "gecko-ffi"))] +impl Header { + #[allow(clippy::unnecessary_cast)] + fn cap(&self) -> usize { + self._cap as usize + } + + fn set_cap(&mut self, cap: usize) { + self._cap = assert_size(cap); + } +} + +/// Singleton that all empty collections share. +/// Note: can't store non-zero ZSTs, we allocate in that case. We could +/// optimize everything to not do that (basically, make ptr == len and branch +/// on size == 0 in every method), but it's a bunch of work for something that +/// doesn't matter much. +#[cfg(any(not(feature = "gecko-ffi"), test, miri))] +static EMPTY_HEADER: Header = Header { _len: 0, _cap: 0 }; + +#[cfg(all(feature = "gecko-ffi", not(test), not(miri)))] +extern "C" { + #[link_name = "sEmptyTArrayHeader"] + static EMPTY_HEADER: Header; +} + +// Utils for computing layouts of allocations + +/// Gets the size necessary to allocate a `ThinVec<T>` with the give capacity. +/// +/// # Panics +/// +/// This will panic if isize::MAX is overflowed at any point. +fn alloc_size<T>(cap: usize) -> usize { + // Compute "real" header size with pointer math + // + // We turn everything into isizes here so that we can catch isize::MAX overflow, + // we never want to allow allocations larger than that! + let header_size = mem::size_of::<Header>() as isize; + let padding = padding::<T>() as isize; + + let data_size = if mem::size_of::<T>() == 0 { + // If we're allocating an array for ZSTs we need a header/padding but no actual + // space for items, so we don't care about the capacity that was requested! + 0 + } else { + let cap: isize = cap.try_into().expect("capacity overflow"); + let elem_size = mem::size_of::<T>() as isize; + elem_size.checked_mul(cap).expect("capacity overflow") + }; + + let final_size = data_size + .checked_add(header_size + padding) + .expect("capacity overflow"); + + // Ok now we can turn it back into a usize (don't need to worry about negatives) + final_size as usize +} + +/// Gets the padding necessary for the array of a `ThinVec<T>` +fn padding<T>() -> usize { + let alloc_align = alloc_align::<T>(); + let header_size = mem::size_of::<Header>(); + + if alloc_align > header_size { + if cfg!(feature = "gecko-ffi") { + panic!( + "nsTArray does not handle alignment above > {} correctly", + header_size + ); + } + alloc_align - header_size + } else { + 0 + } +} + +/// Gets the align necessary to allocate a `ThinVec<T>` +fn alloc_align<T>() -> usize { + max(mem::align_of::<T>(), mem::align_of::<Header>()) +} + +/// Gets the layout necessary to allocate a `ThinVec<T>` +/// +/// # Panics +/// +/// Panics if the required size overflows `isize::MAX`. +fn layout<T>(cap: usize) -> Layout { + unsafe { Layout::from_size_align_unchecked(alloc_size::<T>(cap), alloc_align::<T>()) } +} + +/// Allocates a header (and array) for a `ThinVec<T>` with the given capacity. +/// +/// # Panics +/// +/// Panics if the required size overflows `isize::MAX`. +fn header_with_capacity<T>(cap: usize) -> NonNull<Header> { + debug_assert!(cap > 0); + unsafe { + let layout = layout::<T>(cap); + let header = alloc(layout) as *mut Header; + + if header.is_null() { + handle_alloc_error(layout) + } + + // "Infinite" capacity for zero-sized types: + (*header).set_cap(if mem::size_of::<T>() == 0 { + MAX_CAP + } else { + cap + }); + (*header).set_len(0); + + NonNull::new_unchecked(header) + } +} + +/// See the crate's top level documentation for a description of this type. +#[repr(C)] +pub struct ThinVec<T> { + ptr: NonNull<Header>, + boo: PhantomData<T>, +} + +unsafe impl<T: Sync> Sync for ThinVec<T> {} +unsafe impl<T: Send> Send for ThinVec<T> {} + +/// Creates a `ThinVec` containing the arguments. +/// +// A hack to avoid linking problems with `cargo test --features=gecko-ffi`. +#[cfg_attr(not(feature = "gecko-ffi"), doc = "```")] +#[cfg_attr(feature = "gecko-ffi", doc = "```ignore")] +/// #[macro_use] extern crate thin_vec; +/// +/// fn main() { +/// let v = thin_vec![1, 2, 3]; +/// assert_eq!(v.len(), 3); +/// assert_eq!(v[0], 1); +/// assert_eq!(v[1], 2); +/// assert_eq!(v[2], 3); +/// +/// let v = thin_vec![1; 3]; +/// assert_eq!(v, [1, 1, 1]); +/// } +/// ``` +#[macro_export] +macro_rules! thin_vec { + (@UNIT $($t:tt)*) => (()); + + ($elem:expr; $n:expr) => ({ + let mut vec = $crate::ThinVec::new(); + vec.resize($n, $elem); + vec + }); + () => {$crate::ThinVec::new()}; + ($($x:expr),*) => ({ + let len = [$(thin_vec!(@UNIT $x)),*].len(); + let mut vec = $crate::ThinVec::with_capacity(len); + $(vec.push($x);)* + vec + }); + ($($x:expr,)*) => (thin_vec![$($x),*]); +} + +impl<T> ThinVec<T> { + /// Creates a new empty ThinVec. + /// + /// This will not allocate. + pub fn new() -> ThinVec<T> { + ThinVec::with_capacity(0) + } + + /// Constructs a new, empty `ThinVec<T>` with at least the specified capacity. + /// + /// The vector will be able to hold at least `capacity` elements without + /// reallocating. This method is allowed to allocate for more elements than + /// `capacity`. If `capacity` is 0, the vector will not allocate. + /// + /// It is important to note that although the returned vector has the + /// minimum *capacity* specified, the vector will have a zero *length*. + /// + /// If it is important to know the exact allocated capacity of a `ThinVec`, + /// always use the [`capacity`] method after construction. + /// + /// **NOTE**: unlike `Vec`, `ThinVec` **MUST** allocate once to keep track of non-zero + /// lengths. As such, we cannot provide the same guarantees about ThinVecs + /// of ZSTs not allocating. However the allocation never needs to be resized + /// to add more ZSTs, since the underlying array is still length 0. + /// + /// [Capacity and reallocation]: #capacity-and-reallocation + /// [`capacity`]: Vec::capacity + /// + /// # Panics + /// + /// Panics if the new capacity exceeds `isize::MAX` bytes. + /// + /// # Examples + /// + /// ``` + /// use thin_vec::ThinVec; + /// + /// let mut vec = ThinVec::with_capacity(10); + /// + /// // The vector contains no items, even though it has capacity for more + /// assert_eq!(vec.len(), 0); + /// assert!(vec.capacity() >= 10); + /// + /// // These are all done without reallocating... + /// for i in 0..10 { + /// vec.push(i); + /// } + /// assert_eq!(vec.len(), 10); + /// assert!(vec.capacity() >= 10); + /// + /// // ...but this may make the vector reallocate + /// vec.push(11); + /// assert_eq!(vec.len(), 11); + /// assert!(vec.capacity() >= 11); + /// + /// // A vector of a zero-sized type will always over-allocate, since no + /// // space is needed to store the actual elements. + /// let vec_units = ThinVec::<()>::with_capacity(10); + /// + /// // Only true **without** the gecko-ffi feature! + /// // assert_eq!(vec_units.capacity(), usize::MAX); + /// ``` + pub fn with_capacity(cap: usize) -> ThinVec<T> { + // `padding` contains ~static assertions against types that are + // incompatible with the current feature flags. We also call it to + // invoke these assertions when getting a pointer to the `ThinVec` + // contents, but since we also get a pointer to the contents in the + // `Drop` impl, trippng an assertion along that code path causes a + // double panic. We duplicate the assertion here so that it is + // testable, + let _ = padding::<T>(); + + if cap == 0 { + unsafe { + ThinVec { + ptr: NonNull::new_unchecked(&EMPTY_HEADER as *const Header as *mut Header), + boo: PhantomData, + } + } + } else { + ThinVec { + ptr: header_with_capacity::<T>(cap), + boo: PhantomData, + } + } + } + + // Accessor conveniences + + fn ptr(&self) -> *mut Header { + self.ptr.as_ptr() + } + fn header(&self) -> &Header { + unsafe { self.ptr.as_ref() } + } + fn data_raw(&self) -> *mut T { + // `padding` contains ~static assertions against types that are + // incompatible with the current feature flags. Even if we don't + // care about its result, we should always call it before getting + // a data pointer to guard against invalid types! + let padding = padding::<T>(); + + // Although we ensure the data array is aligned when we allocate, + // we can't do that with the empty singleton. So when it might not + // be properly aligned, we substitute in the NonNull::dangling + // which *is* aligned. + // + // To minimize dynamic branches on `cap` for all accesses + // to the data, we include this guard which should only involve + // compile-time constants. Ideally this should result in the branch + // only be included for types with excessive alignment. + let empty_header_is_aligned = if cfg!(feature = "gecko-ffi") { + // in gecko-ffi mode `padding` will ensure this under + // the assumption that the header has size 8 and the + // static empty singleton is aligned to 8. + true + } else { + // In non-gecko-ffi mode, the empty singleton is just + // naturally aligned to the Header. If the Header is at + // least as aligned as T *and* the padding would have + // been 0, then one-past-the-end of the empty singleton + // *is* a valid data pointer and we can remove the + // `dangling` special case. + mem::align_of::<Header>() >= mem::align_of::<T>() && padding == 0 + }; + + unsafe { + if !empty_header_is_aligned && self.header().cap() == 0 { + NonNull::dangling().as_ptr() + } else { + // This could technically result in overflow, but padding + // would have to be absurdly large for this to occur. + let header_size = mem::size_of::<Header>(); + let ptr = self.ptr.as_ptr() as *mut u8; + ptr.add(header_size + padding) as *mut T + } + } + } + + // This is unsafe when the header is EMPTY_HEADER. + unsafe fn header_mut(&mut self) -> &mut Header { + &mut *self.ptr() + } + + /// Returns the number of elements in the vector, also referred to + /// as its 'length'. + /// + /// # Examples + /// + /// ``` + /// use thin_vec::thin_vec; + /// + /// let a = thin_vec![1, 2, 3]; + /// assert_eq!(a.len(), 3); + /// ``` + pub fn len(&self) -> usize { + self.header().len() + } + + /// Returns `true` if the vector contains no elements. + /// + /// # Examples + /// + /// ``` + /// use thin_vec::ThinVec; + /// + /// let mut v = ThinVec::new(); + /// assert!(v.is_empty()); + /// + /// v.push(1); + /// assert!(!v.is_empty()); + /// ``` + pub fn is_empty(&self) -> bool { + self.len() == 0 + } + + /// Returns the number of elements the vector can hold without + /// reallocating. + /// + /// # Examples + /// + /// ``` + /// use thin_vec::ThinVec; + /// + /// let vec: ThinVec<i32> = ThinVec::with_capacity(10); + /// assert_eq!(vec.capacity(), 10); + /// ``` + pub fn capacity(&self) -> usize { + self.header().cap() + } + + /// Forces the length of the vector to `new_len`. + /// + /// This is a low-level operation that maintains none of the normal + /// invariants of the type. Normally changing the length of a vector + /// is done using one of the safe operations instead, such as + /// [`truncate`], [`resize`], [`extend`], or [`clear`]. + /// + /// [`truncate`]: ThinVec::truncate + /// [`resize`]: ThinVec::resize + /// [`extend`]: ThinVec::extend + /// [`clear`]: ThinVec::clear + /// + /// # Safety + /// + /// - `new_len` must be less than or equal to [`capacity()`]. + /// - The elements at `old_len..new_len` must be initialized. + /// + /// [`capacity()`]: ThinVec::capacity + /// + /// # Examples + /// + /// This method can be useful for situations in which the vector + /// is serving as a buffer for other code, particularly over FFI: + /// + /// ```no_run + /// use thin_vec::ThinVec; + /// + /// # // This is just a minimal skeleton for the doc example; + /// # // don't use this as a starting point for a real library. + /// # pub struct StreamWrapper { strm: *mut std::ffi::c_void } + /// # const Z_OK: i32 = 0; + /// # extern "C" { + /// # fn deflateGetDictionary( + /// # strm: *mut std::ffi::c_void, + /// # dictionary: *mut u8, + /// # dictLength: *mut usize, + /// # ) -> i32; + /// # } + /// # impl StreamWrapper { + /// pub fn get_dictionary(&self) -> Option<ThinVec<u8>> { + /// // Per the FFI method's docs, "32768 bytes is always enough". + /// let mut dict = ThinVec::with_capacity(32_768); + /// let mut dict_length = 0; + /// // SAFETY: When `deflateGetDictionary` returns `Z_OK`, it holds that: + /// // 1. `dict_length` elements were initialized. + /// // 2. `dict_length` <= the capacity (32_768) + /// // which makes `set_len` safe to call. + /// unsafe { + /// // Make the FFI call... + /// let r = deflateGetDictionary(self.strm, dict.as_mut_ptr(), &mut dict_length); + /// if r == Z_OK { + /// // ...and update the length to what was initialized. + /// dict.set_len(dict_length); + /// Some(dict) + /// } else { + /// None + /// } + /// } + /// } + /// # } + /// ``` + /// + /// While the following example is sound, there is a memory leak since + /// the inner vectors were not freed prior to the `set_len` call: + /// + /// ```no_run + /// use thin_vec::thin_vec; + /// + /// let mut vec = thin_vec![thin_vec![1, 0, 0], + /// thin_vec![0, 1, 0], + /// thin_vec![0, 0, 1]]; + /// // SAFETY: + /// // 1. `old_len..0` is empty so no elements need to be initialized. + /// // 2. `0 <= capacity` always holds whatever `capacity` is. + /// unsafe { + /// vec.set_len(0); + /// } + /// ``` + /// + /// Normally, here, one would use [`clear`] instead to correctly drop + /// the contents and thus not leak memory. + pub unsafe fn set_len(&mut self, len: usize) { + if self.is_singleton() { + // A prerequisite of `Vec::set_len` is that `new_len` must be + // less than or equal to capacity(). The same applies here. + assert!(len == 0, "invalid set_len({}) on empty ThinVec", len); + } else { + self.header_mut().set_len(len) + } + } + + // For internal use only, when setting the length and it's known to be the non-singleton. + unsafe fn set_len_non_singleton(&mut self, len: usize) { + self.header_mut().set_len(len) + } + + /// Appends an element to the back of a collection. + /// + /// # Panics + /// + /// Panics if the new capacity exceeds `isize::MAX` bytes. + /// + /// # Examples + /// + /// ``` + /// use thin_vec::thin_vec; + /// + /// let mut vec = thin_vec![1, 2]; + /// vec.push(3); + /// assert_eq!(vec, [1, 2, 3]); + /// ``` + pub fn push(&mut self, val: T) { + let old_len = self.len(); + if old_len == self.capacity() { + self.reserve(1); + } + unsafe { + ptr::write(self.data_raw().add(old_len), val); + self.set_len_non_singleton(old_len + 1); + } + } + + /// Removes the last element from a vector and returns it, or [`None`] if it + /// is empty. + /// + /// # Examples + /// + /// ``` + /// use thin_vec::thin_vec; + /// + /// let mut vec = thin_vec![1, 2, 3]; + /// assert_eq!(vec.pop(), Some(3)); + /// assert_eq!(vec, [1, 2]); + /// ``` + pub fn pop(&mut self) -> Option<T> { + let old_len = self.len(); + if old_len == 0 { + return None; + } + + unsafe { + self.set_len_non_singleton(old_len - 1); + Some(ptr::read(self.data_raw().add(old_len - 1))) + } + } + + /// Inserts an element at position `index` within the vector, shifting all + /// elements after it to the right. + /// + /// # Panics + /// + /// Panics if `index > len`. + /// + /// # Examples + /// + /// ``` + /// use thin_vec::thin_vec; + /// + /// let mut vec = thin_vec![1, 2, 3]; + /// vec.insert(1, 4); + /// assert_eq!(vec, [1, 4, 2, 3]); + /// vec.insert(4, 5); + /// assert_eq!(vec, [1, 4, 2, 3, 5]); + /// ``` + pub fn insert(&mut self, idx: usize, elem: T) { + let old_len = self.len(); + + assert!(idx <= old_len, "Index out of bounds"); + if old_len == self.capacity() { + self.reserve(1); + } + unsafe { + let ptr = self.data_raw(); + ptr::copy(ptr.add(idx), ptr.add(idx + 1), old_len - idx); + ptr::write(ptr.add(idx), elem); + self.set_len_non_singleton(old_len + 1); + } + } + + /// Removes and returns the element at position `index` within the vector, + /// shifting all elements after it to the left. + /// + /// Note: Because this shifts over the remaining elements, it has a + /// worst-case performance of *O*(*n*). If you don't need the order of elements + /// to be preserved, use [`swap_remove`] instead. If you'd like to remove + /// elements from the beginning of the `ThinVec`, consider using `std::collections::VecDeque`. + /// + /// [`swap_remove`]: ThinVec::swap_remove + /// + /// # Panics + /// + /// Panics if `index` is out of bounds. + /// + /// # Examples + /// + /// ``` + /// use thin_vec::thin_vec; + /// + /// let mut v = thin_vec![1, 2, 3]; + /// assert_eq!(v.remove(1), 2); + /// assert_eq!(v, [1, 3]); + /// ``` + pub fn remove(&mut self, idx: usize) -> T { + let old_len = self.len(); + + assert!(idx < old_len, "Index out of bounds"); + + unsafe { + self.set_len_non_singleton(old_len - 1); + let ptr = self.data_raw(); + let val = ptr::read(self.data_raw().add(idx)); + ptr::copy(ptr.add(idx + 1), ptr.add(idx), old_len - idx - 1); + val + } + } + + /// Removes an element from the vector and returns it. + /// + /// The removed element is replaced by the last element of the vector. + /// + /// This does not preserve ordering, but is *O*(1). + /// If you need to preserve the element order, use [`remove`] instead. + /// + /// [`remove`]: ThinVec::remove + /// + /// # Panics + /// + /// Panics if `index` is out of bounds. + /// + /// # Examples + /// + /// ``` + /// use thin_vec::thin_vec; + /// + /// let mut v = thin_vec!["foo", "bar", "baz", "qux"]; + /// + /// assert_eq!(v.swap_remove(1), "bar"); + /// assert_eq!(v, ["foo", "qux", "baz"]); + /// + /// assert_eq!(v.swap_remove(0), "foo"); + /// assert_eq!(v, ["baz", "qux"]); + /// ``` + pub fn swap_remove(&mut self, idx: usize) -> T { + let old_len = self.len(); + + assert!(idx < old_len, "Index out of bounds"); + + unsafe { + let ptr = self.data_raw(); + ptr::swap(ptr.add(idx), ptr.add(old_len - 1)); + self.set_len_non_singleton(old_len - 1); + ptr::read(ptr.add(old_len - 1)) + } + } + + /// Shortens the vector, keeping the first `len` elements and dropping + /// the rest. + /// + /// If `len` is greater than the vector's current length, this has no + /// effect. + /// + /// The [`drain`] method can emulate `truncate`, but causes the excess + /// elements to be returned instead of dropped. + /// + /// Note that this method has no effect on the allocated capacity + /// of the vector. + /// + /// # Examples + /// + /// Truncating a five element vector to two elements: + /// + /// ``` + /// use thin_vec::thin_vec; + /// + /// let mut vec = thin_vec![1, 2, 3, 4, 5]; + /// vec.truncate(2); + /// assert_eq!(vec, [1, 2]); + /// ``` + /// + /// No truncation occurs when `len` is greater than the vector's current + /// length: + /// + /// ``` + /// use thin_vec::thin_vec; + /// + /// let mut vec = thin_vec![1, 2, 3]; + /// vec.truncate(8); + /// assert_eq!(vec, [1, 2, 3]); + /// ``` + /// + /// Truncating when `len == 0` is equivalent to calling the [`clear`] + /// method. + /// + /// ``` + /// use thin_vec::thin_vec; + /// + /// let mut vec = thin_vec![1, 2, 3]; + /// vec.truncate(0); + /// assert_eq!(vec, []); + /// ``` + /// + /// [`clear`]: ThinVec::clear + /// [`drain`]: ThinVec::drain + pub fn truncate(&mut self, len: usize) { + unsafe { + // drop any extra elements + while len < self.len() { + // decrement len before the drop_in_place(), so a panic on Drop + // doesn't re-drop the just-failed value. + let new_len = self.len() - 1; + self.set_len_non_singleton(new_len); + ptr::drop_in_place(self.data_raw().add(new_len)); + } + } + } + + /// Clears the vector, removing all values. + /// + /// Note that this method has no effect on the allocated capacity + /// of the vector. + /// + /// # Examples + /// + /// ``` + /// use thin_vec::thin_vec; + /// + /// let mut v = thin_vec![1, 2, 3]; + /// v.clear(); + /// assert!(v.is_empty()); + /// ``` + pub fn clear(&mut self) { + unsafe { + ptr::drop_in_place(&mut self[..]); + self.set_len(0); // could be the singleton + } + } + + /// Extracts a slice containing the entire vector. + /// + /// Equivalent to `&s[..]`. + /// + /// # Examples + /// + /// ``` + /// use thin_vec::thin_vec; + /// use std::io::{self, Write}; + /// let buffer = thin_vec![1, 2, 3, 5, 8]; + /// io::sink().write(buffer.as_slice()).unwrap(); + /// ``` + pub fn as_slice(&self) -> &[T] { + unsafe { slice::from_raw_parts(self.data_raw(), self.len()) } + } + + /// Extracts a mutable slice of the entire vector. + /// + /// Equivalent to `&mut s[..]`. + /// + /// # Examples + /// + /// ``` + /// use thin_vec::thin_vec; + /// use std::io::{self, Read}; + /// let mut buffer = vec![0; 3]; + /// io::repeat(0b101).read_exact(buffer.as_mut_slice()).unwrap(); + /// ``` + pub fn as_mut_slice(&mut self) -> &mut [T] { + unsafe { slice::from_raw_parts_mut(self.data_raw(), self.len()) } + } + + /// Reserve capacity for at least `additional` more elements to be inserted. + /// + /// May reserve more space than requested, to avoid frequent reallocations. + /// + /// Panics if the new capacity overflows `usize`. + /// + /// Re-allocates only if `self.capacity() < self.len() + additional`. + #[cfg(not(feature = "gecko-ffi"))] + pub fn reserve(&mut self, additional: usize) { + let len = self.len(); + let old_cap = self.capacity(); + let min_cap = len.checked_add(additional).expect("capacity overflow"); + if min_cap <= old_cap { + return; + } + // Ensure the new capacity is at least double, to guarantee exponential growth. + let double_cap = if old_cap == 0 { + // skip to 4 because tiny ThinVecs are dumb; but not if that would cause overflow + if mem::size_of::<T>() > (!0) / 8 { + 1 + } else { + 4 + } + } else { + old_cap.saturating_mul(2) + }; + let new_cap = max(min_cap, double_cap); + unsafe { + self.reallocate(new_cap); + } + } + + /// Reserve capacity for at least `additional` more elements to be inserted. + /// + /// This method mimics the growth algorithm used by the C++ implementation + /// of nsTArray. + #[cfg(feature = "gecko-ffi")] + pub fn reserve(&mut self, additional: usize) { + let elem_size = mem::size_of::<T>(); + + let len = self.len(); + let old_cap = self.capacity(); + let min_cap = len.checked_add(additional).expect("capacity overflow"); + if min_cap <= old_cap { + return; + } + + // The growth logic can't handle zero-sized types, so we have to exit + // early here. + if elem_size == 0 { + unsafe { + self.reallocate(min_cap); + } + return; + } + + let min_cap_bytes = assert_size(min_cap) + .checked_mul(assert_size(elem_size)) + .and_then(|x| x.checked_add(assert_size(mem::size_of::<Header>()))) + .unwrap(); + + // Perform some checked arithmetic to ensure all of the numbers we + // compute will end up in range. + let will_fit = min_cap_bytes.checked_mul(2).is_some(); + if !will_fit { + panic!("Exceeded maximum nsTArray size"); + } + + const SLOW_GROWTH_THRESHOLD: usize = 8 * 1024 * 1024; + + let bytes = if min_cap > SLOW_GROWTH_THRESHOLD { + // Grow by a minimum of 1.125x + let old_cap_bytes = old_cap * elem_size + mem::size_of::<Header>(); + let min_growth = old_cap_bytes + (old_cap_bytes >> 3); + let growth = max(min_growth, min_cap_bytes as usize); + + // Round up to the next megabyte. + const MB: usize = 1 << 20; + MB * ((growth + MB - 1) / MB) + } else { + // Try to allocate backing buffers in powers of two. + min_cap_bytes.next_power_of_two() as usize + }; + + let cap = (bytes - std::mem::size_of::<Header>()) / elem_size; + unsafe { + self.reallocate(cap); + } + } + + /// Reserves the minimum capacity for `additional` more elements to be inserted. + /// + /// Panics if the new capacity overflows `usize`. + /// + /// Re-allocates only if `self.capacity() < self.len() + additional`. + pub fn reserve_exact(&mut self, additional: usize) { + let new_cap = self + .len() + .checked_add(additional) + .expect("capacity overflow"); + let old_cap = self.capacity(); + if new_cap > old_cap { + unsafe { + self.reallocate(new_cap); + } + } + } + + /// Shrinks the capacity of the vector as much as possible. + /// + /// It will drop down as close as possible to the length but the allocator + /// may still inform the vector that there is space for a few more elements. + /// + /// # Examples + /// + /// ``` + /// use thin_vec::ThinVec; + /// + /// let mut vec = ThinVec::with_capacity(10); + /// vec.extend([1, 2, 3]); + /// assert_eq!(vec.capacity(), 10); + /// vec.shrink_to_fit(); + /// assert!(vec.capacity() >= 3); + /// ``` + pub fn shrink_to_fit(&mut self) { + let old_cap = self.capacity(); + let new_cap = self.len(); + if new_cap < old_cap { + if new_cap == 0 { + *self = ThinVec::new(); + } else { + unsafe { + self.reallocate(new_cap); + } + } + } + } + + /// Retains only the elements specified by the predicate. + /// + /// In other words, remove all elements `e` such that `f(&e)` returns `false`. + /// This method operates in place and preserves the order of the retained + /// elements. + /// + /// # Examples + /// + // A hack to avoid linking problems with `cargo test --features=gecko-ffi`. + #[cfg_attr(not(feature = "gecko-ffi"), doc = "```")] + #[cfg_attr(feature = "gecko-ffi", doc = "```ignore")] + /// # #[macro_use] extern crate thin_vec; + /// # fn main() { + /// let mut vec = thin_vec![1, 2, 3, 4]; + /// vec.retain(|&x| x%2 == 0); + /// assert_eq!(vec, [2, 4]); + /// # } + /// ``` + pub fn retain<F>(&mut self, mut f: F) + where + F: FnMut(&T) -> bool, + { + self.retain_mut(|x| f(&*x)); + } + + /// Retains only the elements specified by the predicate, passing a mutable reference to it. + /// + /// In other words, remove all elements `e` such that `f(&mut e)` returns `false`. + /// This method operates in place and preserves the order of the retained + /// elements. + /// + /// # Examples + /// + // A hack to avoid linking problems with `cargo test --features=gecko-ffi`. + #[cfg_attr(not(feature = "gecko-ffi"), doc = "```")] + #[cfg_attr(feature = "gecko-ffi", doc = "```ignore")] + /// # #[macro_use] extern crate thin_vec; + /// # fn main() { + /// let mut vec = thin_vec![1, 2, 3, 4, 5]; + /// vec.retain_mut(|x| { + /// *x += 1; + /// (*x)%2 == 0 + /// }); + /// assert_eq!(vec, [2, 4, 6]); + /// # } + /// ``` + pub fn retain_mut<F>(&mut self, mut f: F) + where + F: FnMut(&mut T) -> bool, + { + let len = self.len(); + let mut del = 0; + { + let v = &mut self[..]; + + for i in 0..len { + if !f(&mut v[i]) { + del += 1; + } else if del > 0 { + v.swap(i - del, i); + } + } + } + if del > 0 { + self.truncate(len - del); + } + } + + /// Removes consecutive elements in the vector that resolve to the same key. + /// + /// If the vector is sorted, this removes all duplicates. + /// + /// # Examples + /// + // A hack to avoid linking problems with `cargo test --features=gecko-ffi`. + #[cfg_attr(not(feature = "gecko-ffi"), doc = "```")] + #[cfg_attr(feature = "gecko-ffi", doc = "```ignore")] + /// # #[macro_use] extern crate thin_vec; + /// # fn main() { + /// let mut vec = thin_vec![10, 20, 21, 30, 20]; + /// + /// vec.dedup_by_key(|i| *i / 10); + /// + /// assert_eq!(vec, [10, 20, 30, 20]); + /// # } + /// ``` + pub fn dedup_by_key<F, K>(&mut self, mut key: F) + where + F: FnMut(&mut T) -> K, + K: PartialEq<K>, + { + self.dedup_by(|a, b| key(a) == key(b)) + } + + /// Removes consecutive elements in the vector according to a predicate. + /// + /// The `same_bucket` function is passed references to two elements from the vector, and + /// returns `true` if the elements compare equal, or `false` if they do not. Only the first + /// of adjacent equal items is kept. + /// + /// If the vector is sorted, this removes all duplicates. + /// + /// # Examples + /// + // A hack to avoid linking problems with `cargo test --features=gecko-ffi`. + #[cfg_attr(not(feature = "gecko-ffi"), doc = "```")] + #[cfg_attr(feature = "gecko-ffi", doc = "```ignore")] + /// # #[macro_use] extern crate thin_vec; + /// # fn main() { + /// let mut vec = thin_vec!["foo", "bar", "Bar", "baz", "bar"]; + /// + /// vec.dedup_by(|a, b| a.eq_ignore_ascii_case(b)); + /// + /// assert_eq!(vec, ["foo", "bar", "baz", "bar"]); + /// # } + /// ``` + #[allow(clippy::swap_ptr_to_ref)] + pub fn dedup_by<F>(&mut self, mut same_bucket: F) + where + F: FnMut(&mut T, &mut T) -> bool, + { + // See the comments in `Vec::dedup` for a detailed explanation of this code. + unsafe { + let ln = self.len(); + if ln <= 1 { + return; + } + + // Avoid bounds checks by using raw pointers. + let p = self.as_mut_ptr(); + let mut r: usize = 1; + let mut w: usize = 1; + + while r < ln { + let p_r = p.add(r); + let p_wm1 = p.add(w - 1); + if !same_bucket(&mut *p_r, &mut *p_wm1) { + if r != w { + let p_w = p_wm1.add(1); + mem::swap(&mut *p_r, &mut *p_w); + } + w += 1; + } + r += 1; + } + + self.truncate(w); + } + } + + /// Splits the collection into two at the given index. + /// + /// Returns a newly allocated vector containing the elements in the range + /// `[at, len)`. After the call, the original vector will be left containing + /// the elements `[0, at)` with its previous capacity unchanged. + /// + /// # Panics + /// + /// Panics if `at > len`. + /// + /// # Examples + /// + /// ``` + /// use thin_vec::thin_vec; + /// + /// let mut vec = thin_vec![1, 2, 3]; + /// let vec2 = vec.split_off(1); + /// assert_eq!(vec, [1]); + /// assert_eq!(vec2, [2, 3]); + /// ``` + pub fn split_off(&mut self, at: usize) -> ThinVec<T> { + let old_len = self.len(); + let new_vec_len = old_len - at; + + assert!(at <= old_len, "Index out of bounds"); + + unsafe { + let mut new_vec = ThinVec::with_capacity(new_vec_len); + + ptr::copy_nonoverlapping(self.data_raw().add(at), new_vec.data_raw(), new_vec_len); + + new_vec.set_len(new_vec_len); // could be the singleton + self.set_len(at); // could be the singleton + + new_vec + } + } + + /// Moves all the elements of `other` into `self`, leaving `other` empty. + /// + /// # Panics + /// + /// Panics if the new capacity exceeds `isize::MAX` bytes. + /// + /// # Examples + /// + /// ``` + /// use thin_vec::thin_vec; + /// + /// let mut vec = thin_vec![1, 2, 3]; + /// let mut vec2 = thin_vec![4, 5, 6]; + /// vec.append(&mut vec2); + /// assert_eq!(vec, [1, 2, 3, 4, 5, 6]); + /// assert_eq!(vec2, []); + /// ``` + pub fn append(&mut self, other: &mut ThinVec<T>) { + self.extend(other.drain(..)) + } + + /// Removes the specified range from the vector in bulk, returning all + /// removed elements as an iterator. If the iterator is dropped before + /// being fully consumed, it drops the remaining removed elements. + /// + /// The returned iterator keeps a mutable borrow on the vector to optimize + /// its implementation. + /// + /// # Panics + /// + /// Panics if the starting point is greater than the end point or if + /// the end point is greater than the length of the vector. + /// + /// # Leaking + /// + /// If the returned iterator goes out of scope without being dropped (due to + /// [`mem::forget`], for example), the vector may have lost and leaked + /// elements arbitrarily, including elements outside the range. + /// + /// # Examples + /// + /// ``` + /// use thin_vec::{ThinVec, thin_vec}; + /// + /// let mut v = thin_vec![1, 2, 3]; + /// let u: ThinVec<_> = v.drain(1..).collect(); + /// assert_eq!(v, &[1]); + /// assert_eq!(u, &[2, 3]); + /// + /// // A full range clears the vector, like `clear()` does + /// v.drain(..); + /// assert_eq!(v, &[]); + /// ``` + pub fn drain<R>(&mut self, range: R) -> Drain<'_, T> + where + R: RangeBounds<usize>, + { + // See comments in the Drain struct itself for details on this + let len = self.len(); + let start = match range.start_bound() { + Bound::Included(&n) => n, + Bound::Excluded(&n) => n + 1, + Bound::Unbounded => 0, + }; + let end = match range.end_bound() { + Bound::Included(&n) => n + 1, + Bound::Excluded(&n) => n, + Bound::Unbounded => len, + }; + assert!(start <= end); + assert!(end <= len); + + unsafe { + // Set our length to the start bound + self.set_len(start); // could be the singleton + + let iter = + slice::from_raw_parts_mut(self.data_raw().add(start), end - start).iter_mut(); + + Drain { + iter, + vec: self, + end, + tail: len - end, + } + } + } + + /// Creates a splicing iterator that replaces the specified range in the vector + /// with the given `replace_with` iterator and yields the removed items. + /// `replace_with` does not need to be the same length as `range`. + /// + /// `range` is removed even if the iterator is not consumed until the end. + /// + /// It is unspecified how many elements are removed from the vector + /// if the `Splice` value is leaked. + /// + /// The input iterator `replace_with` is only consumed when the `Splice` value is dropped. + /// + /// This is optimal if: + /// + /// * The tail (elements in the vector after `range`) is empty, + /// * or `replace_with` yields fewer or equal elements than `range`’s length + /// * or the lower bound of its `size_hint()` is exact. + /// + /// Otherwise, a temporary vector is allocated and the tail is moved twice. + /// + /// # Panics + /// + /// Panics if the starting point is greater than the end point or if + /// the end point is greater than the length of the vector. + /// + /// # Examples + /// + /// ``` + /// use thin_vec::{ThinVec, thin_vec}; + /// + /// let mut v = thin_vec![1, 2, 3, 4]; + /// let new = [7, 8, 9]; + /// let u: ThinVec<_> = v.splice(1..3, new).collect(); + /// assert_eq!(v, &[1, 7, 8, 9, 4]); + /// assert_eq!(u, &[2, 3]); + /// ``` + #[inline] + pub fn splice<R, I>(&mut self, range: R, replace_with: I) -> Splice<'_, I::IntoIter> + where + R: RangeBounds<usize>, + I: IntoIterator<Item = T>, + { + Splice { + drain: self.drain(range), + replace_with: replace_with.into_iter(), + } + } + + /// Resize the buffer and update its capacity, without changing the length. + /// Unsafe because it can cause length to be greater than capacity. + unsafe fn reallocate(&mut self, new_cap: usize) { + debug_assert!(new_cap > 0); + if self.has_allocation() { + let old_cap = self.capacity(); + let ptr = realloc( + self.ptr() as *mut u8, + layout::<T>(old_cap), + alloc_size::<T>(new_cap), + ) as *mut Header; + + if ptr.is_null() { + handle_alloc_error(layout::<T>(new_cap)) + } + (*ptr).set_cap(new_cap); + self.ptr = NonNull::new_unchecked(ptr); + } else { + let new_header = header_with_capacity::<T>(new_cap); + + // If we get here and have a non-zero len, then we must be handling + // a gecko auto array, and we have items in a stack buffer. We shouldn't + // free it, but we should memcopy the contents out of it and mark it as empty. + // + // T is assumed to be trivially relocatable, as this is ~required + // for Rust compatibility anyway. Furthermore, we assume C++ won't try + // to unconditionally destroy the contents of the stack allocated buffer + // (i.e. it's obfuscated behind a union). + // + // In effect, we are partially reimplementing the auto array move constructor + // by leaving behind a valid empty instance. + let len = self.len(); + if cfg!(feature = "gecko-ffi") && len > 0 { + new_header + .as_ptr() + .add(1) + .cast::<T>() + .copy_from_nonoverlapping(self.data_raw(), len); + self.set_len_non_singleton(0); + } + + self.ptr = new_header; + } + } + + #[cfg(feature = "gecko-ffi")] + #[inline] + #[allow(unused_unsafe)] + fn is_singleton(&self) -> bool { + // NOTE: the tests will complain that this "unsafe" isn't needed, but it *IS*! + // In production this refers to an *extern static* which *is* unsafe to reference. + // In tests this refers to a local static because we don't have Firefox's codebase + // providing the symbol! + unsafe { self.ptr.as_ptr() as *const Header == &EMPTY_HEADER } + } + + #[cfg(not(feature = "gecko-ffi"))] + #[inline] + fn is_singleton(&self) -> bool { + self.ptr.as_ptr() as *const Header == &EMPTY_HEADER + } + + #[cfg(feature = "gecko-ffi")] + #[inline] + fn has_allocation(&self) -> bool { + unsafe { !self.is_singleton() && !self.ptr.as_ref().uses_stack_allocated_buffer() } + } + + #[cfg(not(feature = "gecko-ffi"))] + #[inline] + fn has_allocation(&self) -> bool { + !self.is_singleton() + } +} + +impl<T: Clone> ThinVec<T> { + /// Resizes the `Vec` in-place so that `len()` is equal to `new_len`. + /// + /// If `new_len` is greater than `len()`, the `Vec` is extended by the + /// difference, with each additional slot filled with `value`. + /// If `new_len` is less than `len()`, the `Vec` is simply truncated. + /// + /// # Examples + /// + // A hack to avoid linking problems with `cargo test --features=gecko-ffi`. + #[cfg_attr(not(feature = "gecko-ffi"), doc = "```")] + #[cfg_attr(feature = "gecko-ffi", doc = "```ignore")] + /// # #[macro_use] extern crate thin_vec; + /// # fn main() { + /// let mut vec = thin_vec!["hello"]; + /// vec.resize(3, "world"); + /// assert_eq!(vec, ["hello", "world", "world"]); + /// + /// let mut vec = thin_vec![1, 2, 3, 4]; + /// vec.resize(2, 0); + /// assert_eq!(vec, [1, 2]); + /// # } + /// ``` + pub fn resize(&mut self, new_len: usize, value: T) { + let old_len = self.len(); + + if new_len > old_len { + let additional = new_len - old_len; + self.reserve(additional); + for _ in 1..additional { + self.push(value.clone()); + } + // We can write the last element directly without cloning needlessly + if additional > 0 { + self.push(value); + } + } else if new_len < old_len { + self.truncate(new_len); + } + } + + /// Clones and appends all elements in a slice to the `ThinVec`. + /// + /// Iterates over the slice `other`, clones each element, and then appends + /// it to this `ThinVec`. The `other` slice is traversed in-order. + /// + /// Note that this function is same as [`extend`] except that it is + /// specialized to work with slices instead. If and when Rust gets + /// specialization this function will likely be deprecated (but still + /// available). + /// + /// # Examples + /// + /// ``` + /// use thin_vec::thin_vec; + /// + /// let mut vec = thin_vec![1]; + /// vec.extend_from_slice(&[2, 3, 4]); + /// assert_eq!(vec, [1, 2, 3, 4]); + /// ``` + /// + /// [`extend`]: ThinVec::extend + pub fn extend_from_slice(&mut self, other: &[T]) { + self.extend(other.iter().cloned()) + } +} + +impl<T: PartialEq> ThinVec<T> { + /// Removes consecutive repeated elements in the vector. + /// + /// If the vector is sorted, this removes all duplicates. + /// + /// # Examples + /// + // A hack to avoid linking problems with `cargo test --features=gecko-ffi`. + #[cfg_attr(not(feature = "gecko-ffi"), doc = "```")] + #[cfg_attr(feature = "gecko-ffi", doc = "```ignore")] + /// # #[macro_use] extern crate thin_vec; + /// # fn main() { + /// let mut vec = thin_vec![1, 2, 2, 3, 2]; + /// + /// vec.dedup(); + /// + /// assert_eq!(vec, [1, 2, 3, 2]); + /// # } + /// ``` + pub fn dedup(&mut self) { + self.dedup_by(|a, b| a == b) + } +} + +impl<T> Drop for ThinVec<T> { + #[inline] + fn drop(&mut self) { + #[cold] + #[inline(never)] + fn drop_non_singleton<T>(this: &mut ThinVec<T>) { + unsafe { + ptr::drop_in_place(&mut this[..]); + + #[cfg(feature = "gecko-ffi")] + if this.ptr.as_ref().uses_stack_allocated_buffer() { + return; + } + + dealloc(this.ptr() as *mut u8, layout::<T>(this.capacity())) + } + } + + if !self.is_singleton() { + drop_non_singleton(self); + } + } +} + +impl<T> Deref for ThinVec<T> { + type Target = [T]; + + fn deref(&self) -> &[T] { + self.as_slice() + } +} + +impl<T> DerefMut for ThinVec<T> { + fn deref_mut(&mut self) -> &mut [T] { + self.as_mut_slice() + } +} + +impl<T> Borrow<[T]> for ThinVec<T> { + fn borrow(&self) -> &[T] { + self.as_slice() + } +} + +impl<T> BorrowMut<[T]> for ThinVec<T> { + fn borrow_mut(&mut self) -> &mut [T] { + self.as_mut_slice() + } +} + +impl<T> AsRef<[T]> for ThinVec<T> { + fn as_ref(&self) -> &[T] { + self.as_slice() + } +} + +impl<T> Extend<T> for ThinVec<T> { + #[inline] + fn extend<I>(&mut self, iter: I) + where + I: IntoIterator<Item = T>, + { + let iter = iter.into_iter(); + let hint = iter.size_hint().0; + if hint > 0 { + self.reserve(hint); + } + for x in iter { + self.push(x); + } + } +} + +impl<T: fmt::Debug> fmt::Debug for ThinVec<T> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + fmt::Debug::fmt(&**self, f) + } +} + +impl<T> Hash for ThinVec<T> +where + T: Hash, +{ + fn hash<H>(&self, state: &mut H) + where + H: Hasher, + { + self[..].hash(state); + } +} + +impl<T> PartialOrd for ThinVec<T> +where + T: PartialOrd, +{ + #[inline] + fn partial_cmp(&self, other: &ThinVec<T>) -> Option<Ordering> { + self[..].partial_cmp(&other[..]) + } +} + +impl<T> Ord for ThinVec<T> +where + T: Ord, +{ + #[inline] + fn cmp(&self, other: &ThinVec<T>) -> Ordering { + self[..].cmp(&other[..]) + } +} + +impl<A, B> PartialEq<ThinVec<B>> for ThinVec<A> +where + A: PartialEq<B>, +{ + #[inline] + fn eq(&self, other: &ThinVec<B>) -> bool { + self[..] == other[..] + } +} + +impl<A, B> PartialEq<Vec<B>> for ThinVec<A> +where + A: PartialEq<B>, +{ + #[inline] + fn eq(&self, other: &Vec<B>) -> bool { + self[..] == other[..] + } +} + +impl<A, B> PartialEq<[B]> for ThinVec<A> +where + A: PartialEq<B>, +{ + #[inline] + fn eq(&self, other: &[B]) -> bool { + self[..] == other[..] + } +} + +impl<'a, A, B> PartialEq<&'a [B]> for ThinVec<A> +where + A: PartialEq<B>, +{ + #[inline] + fn eq(&self, other: &&'a [B]) -> bool { + self[..] == other[..] + } +} + +// Serde impls based on +// https://github.com/bluss/arrayvec/blob/67ec907a98c0f40c4b76066fed3c1af59d35cf6a/src/arrayvec.rs#L1222-L1267 +#[cfg(feature = "serde")] +impl<T: serde::Serialize> serde::Serialize for ThinVec<T> { + fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error> + where + S: serde::Serializer, + { + serializer.collect_seq(self.as_slice()) + } +} + +#[cfg(feature = "serde")] +impl<'de, T: serde::Deserialize<'de>> serde::Deserialize<'de> for ThinVec<T> { + fn deserialize<D>(deserializer: D) -> Result<Self, D::Error> + where + D: serde::Deserializer<'de>, + { + use serde::de::{SeqAccess, Visitor}; + use serde::Deserialize; + + struct ThinVecVisitor<T>(PhantomData<T>); + + impl<'de, T: Deserialize<'de>> Visitor<'de> for ThinVecVisitor<T> { + type Value = ThinVec<T>; + + fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result { + write!(formatter, "a sequence") + } + + fn visit_seq<SA>(self, mut seq: SA) -> Result<Self::Value, SA::Error> + where + SA: SeqAccess<'de>, + { + // Same policy as + // https://github.com/serde-rs/serde/blob/ce0844b9ecc32377b5e4545d759d385a8c46bc6a/serde/src/private/size_hint.rs#L13 + let initial_capacity = seq.size_hint().unwrap_or_default().min(4096); + let mut values = ThinVec::<T>::with_capacity(initial_capacity); + + while let Some(value) = seq.next_element()? { + values.push(value); + } + + Ok(values) + } + } + + deserializer.deserialize_seq(ThinVecVisitor::<T>(PhantomData)) + } +} + +macro_rules! array_impls { + ($($N:expr)*) => {$( + impl<A, B> PartialEq<[B; $N]> for ThinVec<A> where A: PartialEq<B> { + #[inline] + fn eq(&self, other: &[B; $N]) -> bool { self[..] == other[..] } + } + + impl<'a, A, B> PartialEq<&'a [B; $N]> for ThinVec<A> where A: PartialEq<B> { + #[inline] + fn eq(&self, other: &&'a [B; $N]) -> bool { self[..] == other[..] } + } + )*} +} + +array_impls! { + 0 1 2 3 4 5 6 7 8 9 + 10 11 12 13 14 15 16 17 18 19 + 20 21 22 23 24 25 26 27 28 29 + 30 31 32 +} + +impl<T> Eq for ThinVec<T> where T: Eq {} + +impl<T> IntoIterator for ThinVec<T> { + type Item = T; + type IntoIter = IntoIter<T>; + + fn into_iter(self) -> IntoIter<T> { + IntoIter { + vec: self, + start: 0, + } + } +} + +impl<'a, T> IntoIterator for &'a ThinVec<T> { + type Item = &'a T; + type IntoIter = slice::Iter<'a, T>; + + fn into_iter(self) -> slice::Iter<'a, T> { + self.iter() + } +} + +impl<'a, T> IntoIterator for &'a mut ThinVec<T> { + type Item = &'a mut T; + type IntoIter = slice::IterMut<'a, T>; + + fn into_iter(self) -> slice::IterMut<'a, T> { + self.iter_mut() + } +} + +impl<T> Clone for ThinVec<T> +where + T: Clone, +{ + #[inline] + fn clone(&self) -> ThinVec<T> { + #[cold] + #[inline(never)] + fn clone_non_singleton<T: Clone>(this: &ThinVec<T>) -> ThinVec<T> { + let len = this.len(); + let mut new_vec = ThinVec::<T>::with_capacity(len); + let mut data_raw = new_vec.data_raw(); + for x in this.iter() { + unsafe { + ptr::write(data_raw, x.clone()); + data_raw = data_raw.add(1); + } + } + unsafe { + // `this` is not the singleton, but `new_vec` will be if + // `this` is empty. + new_vec.set_len(len); // could be the singleton + } + new_vec + } + + if self.is_singleton() { + ThinVec::new() + } else { + clone_non_singleton(self) + } + } +} + +impl<T> Default for ThinVec<T> { + fn default() -> ThinVec<T> { + ThinVec::new() + } +} + +impl<T> FromIterator<T> for ThinVec<T> { + #[inline] + fn from_iter<I: IntoIterator<Item = T>>(iter: I) -> ThinVec<T> { + let mut vec = ThinVec::new(); + vec.extend(iter.into_iter()); + vec + } +} + +impl<T: Clone> From<&[T]> for ThinVec<T> { + /// Allocate a `ThinVec<T>` and fill it by cloning `s`'s items. + /// + /// # Examples + /// + /// ``` + /// use thin_vec::{ThinVec, thin_vec}; + /// + /// assert_eq!(ThinVec::from(&[1, 2, 3][..]), thin_vec![1, 2, 3]); + /// ``` + fn from(s: &[T]) -> ThinVec<T> { + s.iter().cloned().collect() + } +} + +#[cfg(not(no_global_oom_handling))] +impl<T: Clone> From<&mut [T]> for ThinVec<T> { + /// Allocate a `ThinVec<T>` and fill it by cloning `s`'s items. + /// + /// # Examples + /// + /// ``` + /// use thin_vec::{ThinVec, thin_vec}; + /// + /// assert_eq!(ThinVec::from(&mut [1, 2, 3][..]), thin_vec![1, 2, 3]); + /// ``` + fn from(s: &mut [T]) -> ThinVec<T> { + s.iter().cloned().collect() + } +} + +impl<T, const N: usize> From<[T; N]> for ThinVec<T> { + /// Allocate a `ThinVec<T>` and move `s`'s items into it. + /// + /// # Examples + /// + /// ``` + /// use thin_vec::{ThinVec, thin_vec}; + /// + /// assert_eq!(ThinVec::from([1, 2, 3]), thin_vec![1, 2, 3]); + /// ``` + fn from(s: [T; N]) -> ThinVec<T> { + std::iter::IntoIterator::into_iter(s).collect() + } +} + +impl<T> From<Box<[T]>> for ThinVec<T> { + /// Convert a boxed slice into a vector by transferring ownership of + /// the existing heap allocation. + /// + /// **NOTE:** unlike `std`, this must reallocate to change the layout! + /// + /// # Examples + /// + /// ``` + /// use thin_vec::{ThinVec, thin_vec}; + /// + /// let b: Box<[i32]> = thin_vec![1, 2, 3].into_iter().collect(); + /// assert_eq!(ThinVec::from(b), thin_vec![1, 2, 3]); + /// ``` + fn from(s: Box<[T]>) -> Self { + // Can just lean on the fact that `Box<[T]>` -> `Vec<T>` is Free. + Vec::from(s).into_iter().collect() + } +} + +impl<T> From<Vec<T>> for ThinVec<T> { + /// Convert a `std::Vec` into a `ThinVec`. + /// + /// **NOTE:** this must reallocate to change the layout! + /// + /// # Examples + /// + /// ``` + /// use thin_vec::{ThinVec, thin_vec}; + /// + /// let b: Vec<i32> = vec![1, 2, 3]; + /// assert_eq!(ThinVec::from(b), thin_vec![1, 2, 3]); + /// ``` + fn from(s: Vec<T>) -> Self { + s.into_iter().collect() + } +} + +impl<T> From<ThinVec<T>> for Vec<T> { + /// Convert a `ThinVec` into a `std::Vec`. + /// + /// **NOTE:** this must reallocate to change the layout! + /// + /// # Examples + /// + /// ``` + /// use thin_vec::{ThinVec, thin_vec}; + /// + /// let b: ThinVec<i32> = thin_vec![1, 2, 3]; + /// assert_eq!(Vec::from(b), vec![1, 2, 3]); + /// ``` + fn from(s: ThinVec<T>) -> Self { + s.into_iter().collect() + } +} + +impl<T> From<ThinVec<T>> for Box<[T]> { + /// Convert a vector into a boxed slice. + /// + /// If `v` has excess capacity, its items will be moved into a + /// newly-allocated buffer with exactly the right capacity. + /// + /// **NOTE:** unlike `std`, this must reallocate to change the layout! + /// + /// # Examples + /// + /// ``` + /// use thin_vec::{ThinVec, thin_vec}; + /// assert_eq!(Box::from(thin_vec![1, 2, 3]), thin_vec![1, 2, 3].into_iter().collect()); + /// ``` + fn from(v: ThinVec<T>) -> Self { + v.into_iter().collect() + } +} + +impl From<&str> for ThinVec<u8> { + /// Allocate a `ThinVec<u8>` and fill it with a UTF-8 string. + /// + /// # Examples + /// + /// ``` + /// use thin_vec::{ThinVec, thin_vec}; + /// + /// assert_eq!(ThinVec::from("123"), thin_vec![b'1', b'2', b'3']); + /// ``` + fn from(s: &str) -> ThinVec<u8> { + From::from(s.as_bytes()) + } +} + +impl<T, const N: usize> TryFrom<ThinVec<T>> for [T; N] { + type Error = ThinVec<T>; + + /// Gets the entire contents of the `ThinVec<T>` as an array, + /// if its size exactly matches that of the requested array. + /// + /// # Examples + /// + /// ``` + /// use thin_vec::{ThinVec, thin_vec}; + /// use std::convert::TryInto; + /// + /// assert_eq!(thin_vec![1, 2, 3].try_into(), Ok([1, 2, 3])); + /// assert_eq!(<ThinVec<i32>>::new().try_into(), Ok([])); + /// ``` + /// + /// If the length doesn't match, the input comes back in `Err`: + /// ``` + /// use thin_vec::{ThinVec, thin_vec}; + /// use std::convert::TryInto; + /// + /// let r: Result<[i32; 4], _> = (0..10).collect::<ThinVec<_>>().try_into(); + /// assert_eq!(r, Err(thin_vec![0, 1, 2, 3, 4, 5, 6, 7, 8, 9])); + /// ``` + /// + /// If you're fine with just getting a prefix of the `ThinVec<T>`, + /// you can call [`.truncate(N)`](ThinVec::truncate) first. + /// ``` + /// use thin_vec::{ThinVec, thin_vec}; + /// use std::convert::TryInto; + /// + /// let mut v = ThinVec::from("hello world"); + /// v.sort(); + /// v.truncate(2); + /// let [a, b]: [_; 2] = v.try_into().unwrap(); + /// assert_eq!(a, b' '); + /// assert_eq!(b, b'd'); + /// ``` + fn try_from(mut vec: ThinVec<T>) -> Result<[T; N], ThinVec<T>> { + if vec.len() != N { + return Err(vec); + } + + // SAFETY: `.set_len(0)` is always sound. + unsafe { vec.set_len(0) }; + + // SAFETY: A `ThinVec`'s pointer is always aligned properly, and + // the alignment the array needs is the same as the items. + // We checked earlier that we have sufficient items. + // The items will not double-drop as the `set_len` + // tells the `ThinVec` not to also drop them. + let array = unsafe { ptr::read(vec.data_raw() as *const [T; N]) }; + Ok(array) + } +} + +/// An iterator that moves out of a vector. +/// +/// This `struct` is created by the [`ThinVec::into_iter`][] +/// (provided by the [`IntoIterator`] trait). +/// +/// # Example +/// +/// ``` +/// use thin_vec::thin_vec; +/// +/// let v = thin_vec![0, 1, 2]; +/// let iter: thin_vec::IntoIter<_> = v.into_iter(); +/// ``` +pub struct IntoIter<T> { + vec: ThinVec<T>, + start: usize, +} + +impl<T> IntoIter<T> { + /// Returns the remaining items of this iterator as a slice. + /// + /// # Examples + /// + /// ``` + /// use thin_vec::thin_vec; + /// + /// let vec = thin_vec!['a', 'b', 'c']; + /// let mut into_iter = vec.into_iter(); + /// assert_eq!(into_iter.as_slice(), &['a', 'b', 'c']); + /// let _ = into_iter.next().unwrap(); + /// assert_eq!(into_iter.as_slice(), &['b', 'c']); + /// ``` + pub fn as_slice(&self) -> &[T] { + unsafe { slice::from_raw_parts(self.vec.data_raw().add(self.start), self.len()) } + } + + /// Returns the remaining items of this iterator as a mutable slice. + /// + /// # Examples + /// + /// ``` + /// use thin_vec::thin_vec; + /// + /// let vec = thin_vec!['a', 'b', 'c']; + /// let mut into_iter = vec.into_iter(); + /// assert_eq!(into_iter.as_slice(), &['a', 'b', 'c']); + /// into_iter.as_mut_slice()[2] = 'z'; + /// assert_eq!(into_iter.next().unwrap(), 'a'); + /// assert_eq!(into_iter.next().unwrap(), 'b'); + /// assert_eq!(into_iter.next().unwrap(), 'z'); + /// ``` + pub fn as_mut_slice(&mut self) -> &mut [T] { + unsafe { &mut *self.as_raw_mut_slice() } + } + + fn as_raw_mut_slice(&mut self) -> *mut [T] { + unsafe { ptr::slice_from_raw_parts_mut(self.vec.data_raw().add(self.start), self.len()) } + } +} + +impl<T> Iterator for IntoIter<T> { + type Item = T; + fn next(&mut self) -> Option<T> { + if self.start == self.vec.len() { + None + } else { + unsafe { + let old_start = self.start; + self.start += 1; + Some(ptr::read(self.vec.data_raw().add(old_start))) + } + } + } + + fn size_hint(&self) -> (usize, Option<usize>) { + let len = self.vec.len() - self.start; + (len, Some(len)) + } +} + +impl<T> DoubleEndedIterator for IntoIter<T> { + fn next_back(&mut self) -> Option<T> { + if self.start == self.vec.len() { + None + } else { + self.vec.pop() + } + } +} + +impl<T> ExactSizeIterator for IntoIter<T> {} + +impl<T> std::iter::FusedIterator for IntoIter<T> {} + +// SAFETY: the length calculation is trivial, we're an array! And if it's wrong we're So Screwed. +#[cfg(feature = "unstable")] +unsafe impl<T> std::iter::TrustedLen for IntoIter<T> {} + +impl<T> Drop for IntoIter<T> { + #[inline] + fn drop(&mut self) { + #[cold] + #[inline(never)] + fn drop_non_singleton<T>(this: &mut IntoIter<T>) { + unsafe { + let mut vec = mem::replace(&mut this.vec, ThinVec::new()); + ptr::drop_in_place(&mut vec[this.start..]); + vec.set_len_non_singleton(0) + } + } + + if !self.vec.is_singleton() { + drop_non_singleton(self); + } + } +} + +impl<T: fmt::Debug> fmt::Debug for IntoIter<T> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_tuple("IntoIter").field(&self.as_slice()).finish() + } +} + +impl<T> AsRef<[T]> for IntoIter<T> { + fn as_ref(&self) -> &[T] { + self.as_slice() + } +} + +impl<T: Clone> Clone for IntoIter<T> { + #[allow(clippy::into_iter_on_ref)] + fn clone(&self) -> Self { + // Just create a new `ThinVec` from the remaining elements and IntoIter it + self.as_slice() + .into_iter() + .cloned() + .collect::<ThinVec<_>>() + .into_iter() + } +} + +/// A draining iterator for `ThinVec<T>`. +/// +/// This `struct` is created by [`ThinVec::drain`]. +/// See its documentation for more. +/// +/// # Example +/// +/// ``` +/// use thin_vec::thin_vec; +/// +/// let mut v = thin_vec![0, 1, 2]; +/// let iter: thin_vec::Drain<_> = v.drain(..); +/// ``` +pub struct Drain<'a, T> { + // Ok so ThinVec::drain takes a range of the ThinVec and yields the contents by-value, + // then backshifts the array. During iteration the array is in an unsound state + // (big deinitialized hole in it), and this is very dangerous. + // + // Our first line of defense is the borrow checker: we have a mutable borrow, so nothing + // can access the ThinVec while we exist. As long as we make sure the ThinVec is in a valid + // state again before we release the borrow, everything should be A-OK! We do this cleanup + // in our Drop impl. + // + // Unfortunately, that's unsound, because mem::forget exists and The Leakpocalypse Is Real. + // So we can't actually guarantee our destructor runs before our borrow expires. Thankfully + // this isn't fatal: we can just set the ThinVec's len to 0 at the start, so if anyone + // leaks the Drain, we just leak everything the ThinVec contained out of spite! If they + // *don't* leak us then we can properly repair the len in our Drop impl. This is known + // as "leak amplification", and is the same approach std uses. + // + // But we can do slightly better than setting the len to 0! The drain breaks us up into + // these parts: + // + // ```text + // + // [A, B, C, D, E, F, G, H, _, _] + // ____ __________ ____ ____ + // | | | | + // prefix drain tail spare-cap + // ``` + // + // As the drain iterator is consumed from both ends (DoubleEnded!), we'll start to look + // like this: + // + // ```text + // [A, B, _, _, E, _, G, H, _, _] + // ____ __________ ____ ____ + // | | | | + // prefix drain tail spare-cap + // ``` + // + // Note that the prefix is always valid and untouched, as such we can set the len + // to the prefix when doing leak-amplification. As a bonus, we can use this value + // to remember where the drain range starts. At the end we'll look like this + // (we exhaust ourselves in our Drop impl): + // + // ```text + // [A, B, _, _, _, _, G, H, _, _] + // _____ __________ _____ ____ + // | | | | + // len drain tail spare-cap + // ``` + // + // And need to become this: + // + // ```text + // [A, B, G, H, _, _, _, _, _, _] + // ___________ ________________ + // | | + // len spare-cap + // ``` + // + // All this requires is moving the tail back to the prefix (stored in `len`) + // and setting `len` to `len + tail_len` to undo the leak amplification. + /// An iterator over the elements we're removing. + /// + /// As we go we'll be `read`ing out of the mutable refs yielded by this. + /// It's ok to use IterMut here because it promises to only take mutable + /// refs to the parts we haven't yielded yet. + /// + /// A downside of this (and the *mut below) is that it makes this type invariant, when + /// technically it could be covariant? + iter: IterMut<'a, T>, + /// The actual ThinVec, which we need to hold onto to undo the leak amplification + /// and backshift the tail into place. This should only be accessed when we're + /// completely done with the IterMut in the `drop` impl of this type (or miri will get mad). + /// + /// Since we set the `len` of this to be before `IterMut`, we can use that `len` + /// to retrieve the index of the start of the drain range later. + vec: *mut ThinVec<T>, + /// The one-past-the-end index of the drain range, or equivalently the start of the tail. + end: usize, + /// The length of the tail. + tail: usize, +} + +impl<'a, T> Iterator for Drain<'a, T> { + type Item = T; + fn next(&mut self) -> Option<T> { + self.iter.next().map(|x| unsafe { ptr::read(x) }) + } + + fn size_hint(&self) -> (usize, Option<usize>) { + self.iter.size_hint() + } +} + +impl<'a, T> DoubleEndedIterator for Drain<'a, T> { + fn next_back(&mut self) -> Option<T> { + self.iter.next_back().map(|x| unsafe { ptr::read(x) }) + } +} + +impl<'a, T> ExactSizeIterator for Drain<'a, T> {} + +// SAFETY: we need to keep track of this perfectly Or Else anyway! +#[cfg(feature = "unstable")] +unsafe impl<T> std::iter::TrustedLen for Drain<'_, T> {} + +impl<T> std::iter::FusedIterator for Drain<'_, T> {} + +impl<'a, T> Drop for Drain<'a, T> { + fn drop(&mut self) { + // Consume the rest of the iterator. + for _ in self.by_ref() {} + + // Move the tail over the drained items, and update the length. + unsafe { + let vec = &mut *self.vec; + + // Don't mutate the empty singleton! + if !vec.is_singleton() { + let old_len = vec.len(); + let start = vec.data_raw().add(old_len); + let end = vec.data_raw().add(self.end); + ptr::copy(end, start, self.tail); + vec.set_len_non_singleton(old_len + self.tail); + } + } + } +} + +impl<T: fmt::Debug> fmt::Debug for Drain<'_, T> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_tuple("Drain").field(&self.iter.as_slice()).finish() + } +} + +impl<'a, T> Drain<'a, T> { + /// Returns the remaining items of this iterator as a slice. + /// + /// # Examples + /// + /// ``` + /// use thin_vec::thin_vec; + /// + /// let mut vec = thin_vec!['a', 'b', 'c']; + /// let mut drain = vec.drain(..); + /// assert_eq!(drain.as_slice(), &['a', 'b', 'c']); + /// let _ = drain.next().unwrap(); + /// assert_eq!(drain.as_slice(), &['b', 'c']); + /// ``` + #[must_use] + pub fn as_slice(&self) -> &[T] { + // SAFETY: this is A-OK because the elements that the underlying + // iterator still points at are still logically initialized and contiguous. + self.iter.as_slice() + } +} + +impl<'a, T> AsRef<[T]> for Drain<'a, T> { + fn as_ref(&self) -> &[T] { + self.as_slice() + } +} + +/// A splicing iterator for `ThinVec`. +/// +/// This struct is created by [`ThinVec::splice`][]. +/// See its documentation for more. +/// +/// # Example +/// +/// ``` +/// use thin_vec::thin_vec; +/// +/// let mut v = thin_vec![0, 1, 2]; +/// let new = [7, 8]; +/// let iter: thin_vec::Splice<_> = v.splice(1.., new); +/// ``` +#[derive(Debug)] +pub struct Splice<'a, I: Iterator + 'a> { + drain: Drain<'a, I::Item>, + replace_with: I, +} + +impl<I: Iterator> Iterator for Splice<'_, I> { + type Item = I::Item; + + fn next(&mut self) -> Option<Self::Item> { + self.drain.next() + } + + fn size_hint(&self) -> (usize, Option<usize>) { + self.drain.size_hint() + } +} + +impl<I: Iterator> DoubleEndedIterator for Splice<'_, I> { + fn next_back(&mut self) -> Option<Self::Item> { + self.drain.next_back() + } +} + +impl<I: Iterator> ExactSizeIterator for Splice<'_, I> {} + +impl<I: Iterator> Drop for Splice<'_, I> { + fn drop(&mut self) { + // Ensure we've fully drained out the range + self.drain.by_ref().for_each(drop); + + unsafe { + // If there's no tail elements, then the inner ThinVec is already + // correct and we can just extend it like normal. + if self.drain.tail == 0 { + (*self.drain.vec).extend(self.replace_with.by_ref()); + return; + } + + // First fill the range left by drain(). + if !self.drain.fill(&mut self.replace_with) { + return; + } + + // There may be more elements. Use the lower bound as an estimate. + let (lower_bound, _upper_bound) = self.replace_with.size_hint(); + if lower_bound > 0 { + self.drain.move_tail(lower_bound); + if !self.drain.fill(&mut self.replace_with) { + return; + } + } + + // Collect any remaining elements. + // This is a zero-length vector which does not allocate if `lower_bound` was exact. + let mut collected = self + .replace_with + .by_ref() + .collect::<Vec<I::Item>>() + .into_iter(); + // Now we have an exact count. + if collected.len() > 0 { + self.drain.move_tail(collected.len()); + let filled = self.drain.fill(&mut collected); + debug_assert!(filled); + debug_assert_eq!(collected.len(), 0); + } + } + // Let `Drain::drop` move the tail back if necessary and restore `vec.len`. + } +} + +/// Private helper methods for `Splice::drop` +impl<T> Drain<'_, T> { + /// The range from `self.vec.len` to `self.tail_start` contains elements + /// that have been moved out. + /// Fill that range as much as possible with new elements from the `replace_with` iterator. + /// Returns `true` if we filled the entire range. (`replace_with.next()` didn’t return `None`.) + unsafe fn fill<I: Iterator<Item = T>>(&mut self, replace_with: &mut I) -> bool { + let vec = unsafe { &mut *self.vec }; + let range_start = vec.len(); + let range_end = self.end; + let range_slice = unsafe { + slice::from_raw_parts_mut(vec.data_raw().add(range_start), range_end - range_start) + }; + + for place in range_slice { + if let Some(new_item) = replace_with.next() { + unsafe { ptr::write(place, new_item) }; + vec.set_len(vec.len() + 1); + } else { + return false; + } + } + true + } + + /// Makes room for inserting more elements before the tail. + unsafe fn move_tail(&mut self, additional: usize) { + let vec = unsafe { &mut *self.vec }; + let len = self.end + self.tail; + vec.reserve(len.checked_add(additional).expect("capacity overflow")); + + let new_tail_start = self.end + additional; + unsafe { + let src = vec.data_raw().add(self.end); + let dst = vec.data_raw().add(new_tail_start); + ptr::copy(src, dst, self.tail); + } + self.end = new_tail_start; + } +} + +/// Write is implemented for `ThinVec<u8>` by appending to the vector. +/// The vector will grow as needed. +/// This implementation is identical to the one for `Vec<u8>`. +impl io::Write for ThinVec<u8> { + #[inline] + fn write(&mut self, buf: &[u8]) -> io::Result<usize> { + self.extend_from_slice(buf); + Ok(buf.len()) + } + + #[inline] + fn write_all(&mut self, buf: &[u8]) -> io::Result<()> { + self.extend_from_slice(buf); + Ok(()) + } + + #[inline] + fn flush(&mut self) -> io::Result<()> { + Ok(()) + } +} + +// TODO: a million Index impls + +#[cfg(test)] +mod tests { + use super::{ThinVec, MAX_CAP}; + + #[test] + fn test_size_of() { + use std::mem::size_of; + assert_eq!(size_of::<ThinVec<u8>>(), size_of::<&u8>()); + + assert_eq!(size_of::<Option<ThinVec<u8>>>(), size_of::<&u8>()); + } + + #[test] + fn test_drop_empty() { + ThinVec::<u8>::new(); + } + + #[test] + fn test_data_ptr_alignment() { + let v = ThinVec::<u16>::new(); + assert!(v.data_raw() as usize % 2 == 0); + + let v = ThinVec::<u32>::new(); + assert!(v.data_raw() as usize % 4 == 0); + + let v = ThinVec::<u64>::new(); + assert!(v.data_raw() as usize % 8 == 0); + } + + #[test] + #[cfg_attr(feature = "gecko-ffi", should_panic)] + fn test_overaligned_type_is_rejected_for_gecko_ffi_mode() { + #[repr(align(16))] + struct Align16(u8); + + let v = ThinVec::<Align16>::new(); + assert!(v.data_raw() as usize % 16 == 0); + } + + #[test] + fn test_partial_eq() { + assert_eq!(thin_vec![0], thin_vec![0]); + assert_ne!(thin_vec![0], thin_vec![1]); + assert_eq!(thin_vec![1, 2, 3], vec![1, 2, 3]); + } + + #[test] + fn test_alloc() { + let mut v = ThinVec::new(); + assert!(!v.has_allocation()); + v.push(1); + assert!(v.has_allocation()); + v.pop(); + assert!(v.has_allocation()); + v.shrink_to_fit(); + assert!(!v.has_allocation()); + v.reserve(64); + assert!(v.has_allocation()); + v = ThinVec::with_capacity(64); + assert!(v.has_allocation()); + v = ThinVec::with_capacity(0); + assert!(!v.has_allocation()); + } + + #[test] + fn test_drain_items() { + let mut vec = thin_vec![1, 2, 3]; + let mut vec2 = thin_vec![]; + for i in vec.drain(..) { + vec2.push(i); + } + assert_eq!(vec, []); + assert_eq!(vec2, [1, 2, 3]); + } + + #[test] + fn test_drain_items_reverse() { + let mut vec = thin_vec![1, 2, 3]; + let mut vec2 = thin_vec![]; + for i in vec.drain(..).rev() { + vec2.push(i); + } + assert_eq!(vec, []); + assert_eq!(vec2, [3, 2, 1]); + } + + #[test] + fn test_drain_items_zero_sized() { + let mut vec = thin_vec![(), (), ()]; + let mut vec2 = thin_vec![]; + for i in vec.drain(..) { + vec2.push(i); + } + assert_eq!(vec, []); + assert_eq!(vec2, [(), (), ()]); + } + + #[test] + #[should_panic] + fn test_drain_out_of_bounds() { + let mut v = thin_vec![1, 2, 3, 4, 5]; + v.drain(5..6); + } + + #[test] + fn test_drain_range() { + let mut v = thin_vec![1, 2, 3, 4, 5]; + for _ in v.drain(4..) {} + assert_eq!(v, &[1, 2, 3, 4]); + + let mut v: ThinVec<_> = (1..6).map(|x| x.to_string()).collect(); + for _ in v.drain(1..4) {} + assert_eq!(v, &[1.to_string(), 5.to_string()]); + + let mut v: ThinVec<_> = (1..6).map(|x| x.to_string()).collect(); + for _ in v.drain(1..4).rev() {} + assert_eq!(v, &[1.to_string(), 5.to_string()]); + + let mut v: ThinVec<_> = thin_vec![(); 5]; + for _ in v.drain(1..4).rev() {} + assert_eq!(v, &[(), ()]); + } + + #[test] + fn test_drain_max_vec_size() { + let mut v = ThinVec::<()>::with_capacity(MAX_CAP); + unsafe { + v.set_len(MAX_CAP); + } + for _ in v.drain(MAX_CAP - 1..) {} + assert_eq!(v.len(), MAX_CAP - 1); + } + + #[test] + fn test_clear() { + let mut v = ThinVec::<i32>::new(); + assert_eq!(v.len(), 0); + assert_eq!(v.capacity(), 0); + assert_eq!(&v[..], &[]); + + v.clear(); + assert_eq!(v.len(), 0); + assert_eq!(v.capacity(), 0); + assert_eq!(&v[..], &[]); + + v.push(1); + v.push(2); + assert_eq!(v.len(), 2); + assert!(v.capacity() >= 2); + assert_eq!(&v[..], &[1, 2]); + + v.clear(); + assert_eq!(v.len(), 0); + assert!(v.capacity() >= 2); + assert_eq!(&v[..], &[]); + + v.push(3); + v.push(4); + assert_eq!(v.len(), 2); + assert!(v.capacity() >= 2); + assert_eq!(&v[..], &[3, 4]); + + v.clear(); + assert_eq!(v.len(), 0); + assert!(v.capacity() >= 2); + assert_eq!(&v[..], &[]); + + v.clear(); + assert_eq!(v.len(), 0); + assert!(v.capacity() >= 2); + assert_eq!(&v[..], &[]); + } + + #[test] + fn test_empty_singleton_torture() { + { + let mut v = ThinVec::<i32>::new(); + assert_eq!(v.len(), 0); + assert_eq!(v.capacity(), 0); + assert!(v.is_empty()); + assert_eq!(&v[..], &[]); + assert_eq!(&mut v[..], &mut []); + + assert_eq!(v.pop(), None); + assert_eq!(v.len(), 0); + assert_eq!(v.capacity(), 0); + assert_eq!(&v[..], &[]); + } + + { + let v = ThinVec::<i32>::new(); + assert_eq!(v.into_iter().count(), 0); + + let v = ThinVec::<i32>::new(); + for _ in v.into_iter() { + unreachable!(); + } + } + + { + let mut v = ThinVec::<i32>::new(); + assert_eq!(v.drain(..).len(), 0); + + for _ in v.drain(..) { + unreachable!() + } + + assert_eq!(v.len(), 0); + assert_eq!(v.capacity(), 0); + assert_eq!(&v[..], &[]); + } + + { + let mut v = ThinVec::<i32>::new(); + assert_eq!(v.splice(.., []).len(), 0); + + for _ in v.splice(.., []) { + unreachable!() + } + + assert_eq!(v.len(), 0); + assert_eq!(v.capacity(), 0); + assert_eq!(&v[..], &[]); + } + + { + let mut v = ThinVec::<i32>::new(); + v.truncate(1); + assert_eq!(v.len(), 0); + assert_eq!(v.capacity(), 0); + assert_eq!(&v[..], &[]); + + v.truncate(0); + assert_eq!(v.len(), 0); + assert_eq!(v.capacity(), 0); + assert_eq!(&v[..], &[]); + } + + { + let mut v = ThinVec::<i32>::new(); + v.shrink_to_fit(); + assert_eq!(v.len(), 0); + assert_eq!(v.capacity(), 0); + assert_eq!(&v[..], &[]); + } + + { + let mut v = ThinVec::<i32>::new(); + let new = v.split_off(0); + assert_eq!(v.len(), 0); + assert_eq!(v.capacity(), 0); + assert_eq!(&v[..], &[]); + + assert_eq!(new.len(), 0); + assert_eq!(new.capacity(), 0); + assert_eq!(&new[..], &[]); + } + + { + let mut v = ThinVec::<i32>::new(); + let mut other = ThinVec::<i32>::new(); + v.append(&mut other); + + assert_eq!(v.len(), 0); + assert_eq!(v.capacity(), 0); + assert_eq!(&v[..], &[]); + + assert_eq!(other.len(), 0); + assert_eq!(other.capacity(), 0); + assert_eq!(&other[..], &[]); + } + + { + let mut v = ThinVec::<i32>::new(); + v.reserve(0); + + assert_eq!(v.len(), 0); + assert_eq!(v.capacity(), 0); + assert_eq!(&v[..], &[]); + } + + { + let mut v = ThinVec::<i32>::new(); + v.reserve_exact(0); + + assert_eq!(v.len(), 0); + assert_eq!(v.capacity(), 0); + assert_eq!(&v[..], &[]); + } + + { + let mut v = ThinVec::<i32>::new(); + v.reserve(0); + + assert_eq!(v.len(), 0); + assert_eq!(v.capacity(), 0); + assert_eq!(&v[..], &[]); + } + + { + let v = ThinVec::<i32>::with_capacity(0); + + assert_eq!(v.len(), 0); + assert_eq!(v.capacity(), 0); + assert_eq!(&v[..], &[]); + } + + { + let v = ThinVec::<i32>::default(); + + assert_eq!(v.len(), 0); + assert_eq!(v.capacity(), 0); + assert_eq!(&v[..], &[]); + } + + { + let mut v = ThinVec::<i32>::new(); + v.retain(|_| unreachable!()); + + assert_eq!(v.len(), 0); + assert_eq!(v.capacity(), 0); + assert_eq!(&v[..], &[]); + } + + { + let mut v = ThinVec::<i32>::new(); + v.retain_mut(|_| unreachable!()); + + assert_eq!(v.len(), 0); + assert_eq!(v.capacity(), 0); + assert_eq!(&v[..], &[]); + } + + { + let mut v = ThinVec::<i32>::new(); + v.dedup_by_key(|x| *x); + + assert_eq!(v.len(), 0); + assert_eq!(v.capacity(), 0); + assert_eq!(&v[..], &[]); + } + + { + let mut v = ThinVec::<i32>::new(); + v.dedup_by(|_, _| unreachable!()); + + assert_eq!(v.len(), 0); + assert_eq!(v.capacity(), 0); + assert_eq!(&v[..], &[]); + } + + { + let v = ThinVec::<i32>::new(); + let v = v.clone(); + + assert_eq!(v.len(), 0); + assert_eq!(v.capacity(), 0); + assert_eq!(&v[..], &[]); + } + } + + #[test] + fn test_clone() { + let mut v = ThinVec::<i32>::new(); + assert!(v.is_singleton()); + v.push(0); + v.pop(); + assert!(!v.is_singleton()); + + let v2 = v.clone(); + assert!(v2.is_singleton()); + } +} + +#[cfg(test)] +mod std_tests { + #![allow(clippy::reversed_empty_ranges)] + + use super::*; + use std::mem::size_of; + use std::usize; + + struct DropCounter<'a> { + count: &'a mut u32, + } + + impl<'a> Drop for DropCounter<'a> { + fn drop(&mut self) { + *self.count += 1; + } + } + + #[test] + fn test_small_vec_struct() { + assert!(size_of::<ThinVec<u8>>() == size_of::<usize>()); + } + + #[test] + fn test_double_drop() { + struct TwoVec<T> { + x: ThinVec<T>, + y: ThinVec<T>, + } + + let (mut count_x, mut count_y) = (0, 0); + { + let mut tv = TwoVec { + x: ThinVec::new(), + y: ThinVec::new(), + }; + tv.x.push(DropCounter { + count: &mut count_x, + }); + tv.y.push(DropCounter { + count: &mut count_y, + }); + + // If ThinVec had a drop flag, here is where it would be zeroed. + // Instead, it should rely on its internal state to prevent + // doing anything significant when dropped multiple times. + drop(tv.x); + + // Here tv goes out of scope, tv.y should be dropped, but not tv.x. + } + + assert_eq!(count_x, 1); + assert_eq!(count_y, 1); + } + + #[test] + fn test_reserve() { + let mut v = ThinVec::new(); + assert_eq!(v.capacity(), 0); + + v.reserve(2); + assert!(v.capacity() >= 2); + + for i in 0..16 { + v.push(i); + } + + assert!(v.capacity() >= 16); + v.reserve(16); + assert!(v.capacity() >= 32); + + v.push(16); + + v.reserve(16); + assert!(v.capacity() >= 33) + } + + #[test] + fn test_extend() { + let mut v = ThinVec::<usize>::new(); + let mut w = ThinVec::new(); + v.extend(w.clone()); + assert_eq!(v, &[]); + + v.extend(0..3); + for i in 0..3 { + w.push(i) + } + + assert_eq!(v, w); + + v.extend(3..10); + for i in 3..10 { + w.push(i) + } + + assert_eq!(v, w); + + v.extend(w.clone()); // specializes to `append` + assert!(v.iter().eq(w.iter().chain(w.iter()))); + + // Zero sized types + #[derive(PartialEq, Debug)] + struct Foo; + + let mut a = ThinVec::new(); + let b = thin_vec![Foo, Foo]; + + a.extend(b); + assert_eq!(a, &[Foo, Foo]); + + // Double drop + let mut count_x = 0; + { + let mut x = ThinVec::new(); + let y = thin_vec![DropCounter { + count: &mut count_x + }]; + x.extend(y); + } + + assert_eq!(count_x, 1); + } + + /* TODO: implement extend for Iter<&Copy> + #[test] + fn test_extend_ref() { + let mut v = thin_vec![1, 2]; + v.extend(&[3, 4, 5]); + + assert_eq!(v.len(), 5); + assert_eq!(v, [1, 2, 3, 4, 5]); + + let w = thin_vec![6, 7]; + v.extend(&w); + + assert_eq!(v.len(), 7); + assert_eq!(v, [1, 2, 3, 4, 5, 6, 7]); + } + */ + + #[test] + fn test_slice_from_mut() { + let mut values = thin_vec![1, 2, 3, 4, 5]; + { + let slice = &mut values[2..]; + assert!(slice == [3, 4, 5]); + for p in slice { + *p += 2; + } + } + + assert!(values == [1, 2, 5, 6, 7]); + } + + #[test] + fn test_slice_to_mut() { + let mut values = thin_vec![1, 2, 3, 4, 5]; + { + let slice = &mut values[..2]; + assert!(slice == [1, 2]); + for p in slice { + *p += 1; + } + } + + assert!(values == [2, 3, 3, 4, 5]); + } + + #[test] + fn test_split_at_mut() { + let mut values = thin_vec![1, 2, 3, 4, 5]; + { + let (left, right) = values.split_at_mut(2); + { + let left: &[_] = left; + assert!(left[..left.len()] == [1, 2]); + } + for p in left { + *p += 1; + } + + { + let right: &[_] = right; + assert!(right[..right.len()] == [3, 4, 5]); + } + for p in right { + *p += 2; + } + } + + assert_eq!(values, [2, 3, 5, 6, 7]); + } + + #[test] + fn test_clone() { + let v: ThinVec<i32> = thin_vec![]; + let w = thin_vec![1, 2, 3]; + + assert_eq!(v, v.clone()); + + let z = w.clone(); + assert_eq!(w, z); + // they should be disjoint in memory. + assert!(w.as_ptr() != z.as_ptr()) + } + + #[test] + fn test_clone_from() { + let mut v = thin_vec![]; + let three: ThinVec<Box<_>> = thin_vec![Box::new(1), Box::new(2), Box::new(3)]; + let two: ThinVec<Box<_>> = thin_vec![Box::new(4), Box::new(5)]; + // zero, long + v.clone_from(&three); + assert_eq!(v, three); + + // equal + v.clone_from(&three); + assert_eq!(v, three); + + // long, short + v.clone_from(&two); + assert_eq!(v, two); + + // short, long + v.clone_from(&three); + assert_eq!(v, three) + } + + #[test] + fn test_retain() { + let mut vec = thin_vec![1, 2, 3, 4]; + vec.retain(|&x| x % 2 == 0); + assert_eq!(vec, [2, 4]); + } + + #[test] + fn test_retain_mut() { + let mut vec = thin_vec![9, 9, 9, 9]; + let mut i = 0; + vec.retain_mut(|x| { + i += 1; + *x = i; + i != 4 + }); + assert_eq!(vec, [1, 2, 3]); + } + + #[test] + fn test_dedup() { + fn case(a: ThinVec<i32>, b: ThinVec<i32>) { + let mut v = a; + v.dedup(); + assert_eq!(v, b); + } + case(thin_vec![], thin_vec![]); + case(thin_vec![1], thin_vec![1]); + case(thin_vec![1, 1], thin_vec![1]); + case(thin_vec![1, 2, 3], thin_vec![1, 2, 3]); + case(thin_vec![1, 1, 2, 3], thin_vec![1, 2, 3]); + case(thin_vec![1, 2, 2, 3], thin_vec![1, 2, 3]); + case(thin_vec![1, 2, 3, 3], thin_vec![1, 2, 3]); + case(thin_vec![1, 1, 2, 2, 2, 3, 3], thin_vec![1, 2, 3]); + } + + #[test] + fn test_dedup_by_key() { + fn case(a: ThinVec<i32>, b: ThinVec<i32>) { + let mut v = a; + v.dedup_by_key(|i| *i / 10); + assert_eq!(v, b); + } + case(thin_vec![], thin_vec![]); + case(thin_vec![10], thin_vec![10]); + case(thin_vec![10, 11], thin_vec![10]); + case(thin_vec![10, 20, 30], thin_vec![10, 20, 30]); + case(thin_vec![10, 11, 20, 30], thin_vec![10, 20, 30]); + case(thin_vec![10, 20, 21, 30], thin_vec![10, 20, 30]); + case(thin_vec![10, 20, 30, 31], thin_vec![10, 20, 30]); + case(thin_vec![10, 11, 20, 21, 22, 30, 31], thin_vec![10, 20, 30]); + } + + #[test] + fn test_dedup_by() { + let mut vec = thin_vec!["foo", "bar", "Bar", "baz", "bar"]; + vec.dedup_by(|a, b| a.eq_ignore_ascii_case(b)); + + assert_eq!(vec, ["foo", "bar", "baz", "bar"]); + + let mut vec = thin_vec![("foo", 1), ("foo", 2), ("bar", 3), ("bar", 4), ("bar", 5)]; + vec.dedup_by(|a, b| { + a.0 == b.0 && { + b.1 += a.1; + true + } + }); + + assert_eq!(vec, [("foo", 3), ("bar", 12)]); + } + + #[test] + fn test_dedup_unique() { + let mut v0: ThinVec<Box<_>> = thin_vec![Box::new(1), Box::new(1), Box::new(2), Box::new(3)]; + v0.dedup(); + let mut v1: ThinVec<Box<_>> = thin_vec![Box::new(1), Box::new(2), Box::new(2), Box::new(3)]; + v1.dedup(); + let mut v2: ThinVec<Box<_>> = thin_vec![Box::new(1), Box::new(2), Box::new(3), Box::new(3)]; + v2.dedup(); + // If the boxed pointers were leaked or otherwise misused, valgrind + // and/or rt should raise errors. + } + + #[test] + fn zero_sized_values() { + let mut v = ThinVec::new(); + assert_eq!(v.len(), 0); + v.push(()); + assert_eq!(v.len(), 1); + v.push(()); + assert_eq!(v.len(), 2); + assert_eq!(v.pop(), Some(())); + assert_eq!(v.pop(), Some(())); + assert_eq!(v.pop(), None); + + assert_eq!(v.iter().count(), 0); + v.push(()); + assert_eq!(v.iter().count(), 1); + v.push(()); + assert_eq!(v.iter().count(), 2); + + for &() in &v {} + + assert_eq!(v.iter_mut().count(), 2); + v.push(()); + assert_eq!(v.iter_mut().count(), 3); + v.push(()); + assert_eq!(v.iter_mut().count(), 4); + + for &mut () in &mut v {} + unsafe { + v.set_len(0); + } + assert_eq!(v.iter_mut().count(), 0); + } + + #[test] + fn test_partition() { + assert_eq!( + thin_vec![].into_iter().partition(|x: &i32| *x < 3), + (thin_vec![], thin_vec![]) + ); + assert_eq!( + thin_vec![1, 2, 3].into_iter().partition(|x| *x < 4), + (thin_vec![1, 2, 3], thin_vec![]) + ); + assert_eq!( + thin_vec![1, 2, 3].into_iter().partition(|x| *x < 2), + (thin_vec![1], thin_vec![2, 3]) + ); + assert_eq!( + thin_vec![1, 2, 3].into_iter().partition(|x| *x < 0), + (thin_vec![], thin_vec![1, 2, 3]) + ); + } + + #[test] + fn test_zip_unzip() { + let z1 = thin_vec![(1, 4), (2, 5), (3, 6)]; + + let (left, right): (ThinVec<_>, ThinVec<_>) = z1.iter().cloned().unzip(); + + assert_eq!((1, 4), (left[0], right[0])); + assert_eq!((2, 5), (left[1], right[1])); + assert_eq!((3, 6), (left[2], right[2])); + } + + #[test] + fn test_vec_truncate_drop() { + static mut DROPS: u32 = 0; + struct Elem(i32); + impl Drop for Elem { + fn drop(&mut self) { + unsafe { + DROPS += 1; + } + } + } + + let mut v = thin_vec![Elem(1), Elem(2), Elem(3), Elem(4), Elem(5)]; + assert_eq!(unsafe { DROPS }, 0); + v.truncate(3); + assert_eq!(unsafe { DROPS }, 2); + v.truncate(0); + assert_eq!(unsafe { DROPS }, 5); + } + + #[test] + #[should_panic] + fn test_vec_truncate_fail() { + struct BadElem(i32); + impl Drop for BadElem { + fn drop(&mut self) { + let BadElem(ref mut x) = *self; + if *x == 0xbadbeef { + panic!("BadElem panic: 0xbadbeef") + } + } + } + + let mut v = thin_vec![BadElem(1), BadElem(2), BadElem(0xbadbeef), BadElem(4)]; + v.truncate(0); + } + + #[test] + fn test_index() { + let vec = thin_vec![1, 2, 3]; + assert!(vec[1] == 2); + } + + #[test] + #[should_panic] + fn test_index_out_of_bounds() { + let vec = thin_vec![1, 2, 3]; + let _ = vec[3]; + } + + #[test] + #[should_panic] + fn test_slice_out_of_bounds_1() { + let x = thin_vec![1, 2, 3, 4, 5]; + let _ = &x[!0..]; + } + + #[test] + #[should_panic] + fn test_slice_out_of_bounds_2() { + let x = thin_vec![1, 2, 3, 4, 5]; + let _ = &x[..6]; + } + + #[test] + #[should_panic] + fn test_slice_out_of_bounds_3() { + let x = thin_vec![1, 2, 3, 4, 5]; + let _ = &x[!0..4]; + } + + #[test] + #[should_panic] + fn test_slice_out_of_bounds_4() { + let x = thin_vec![1, 2, 3, 4, 5]; + let _ = &x[1..6]; + } + + #[test] + #[should_panic] + fn test_slice_out_of_bounds_5() { + let x = thin_vec![1, 2, 3, 4, 5]; + let _ = &x[3..2]; + } + + #[test] + #[should_panic] + fn test_swap_remove_empty() { + let mut vec = ThinVec::<i32>::new(); + vec.swap_remove(0); + } + + #[test] + fn test_move_items() { + let vec = thin_vec![1, 2, 3]; + let mut vec2 = thin_vec![]; + for i in vec { + vec2.push(i); + } + assert_eq!(vec2, [1, 2, 3]); + } + + #[test] + fn test_move_items_reverse() { + let vec = thin_vec![1, 2, 3]; + let mut vec2 = thin_vec![]; + for i in vec.into_iter().rev() { + vec2.push(i); + } + assert_eq!(vec2, [3, 2, 1]); + } + + #[test] + fn test_move_items_zero_sized() { + let vec = thin_vec![(), (), ()]; + let mut vec2 = thin_vec![]; + for i in vec { + vec2.push(i); + } + assert_eq!(vec2, [(), (), ()]); + } + + #[test] + fn test_drain_items() { + let mut vec = thin_vec![1, 2, 3]; + let mut vec2 = thin_vec![]; + for i in vec.drain(..) { + vec2.push(i); + } + assert_eq!(vec, []); + assert_eq!(vec2, [1, 2, 3]); + } + + #[test] + fn test_drain_items_reverse() { + let mut vec = thin_vec![1, 2, 3]; + let mut vec2 = thin_vec![]; + for i in vec.drain(..).rev() { + vec2.push(i); + } + assert_eq!(vec, []); + assert_eq!(vec2, [3, 2, 1]); + } + + #[test] + fn test_drain_items_zero_sized() { + let mut vec = thin_vec![(), (), ()]; + let mut vec2 = thin_vec![]; + for i in vec.drain(..) { + vec2.push(i); + } + assert_eq!(vec, []); + assert_eq!(vec2, [(), (), ()]); + } + + #[test] + #[should_panic] + fn test_drain_out_of_bounds() { + let mut v = thin_vec![1, 2, 3, 4, 5]; + v.drain(5..6); + } + + #[test] + fn test_drain_range() { + let mut v = thin_vec![1, 2, 3, 4, 5]; + for _ in v.drain(4..) {} + assert_eq!(v, &[1, 2, 3, 4]); + + let mut v: ThinVec<_> = (1..6).map(|x| x.to_string()).collect(); + for _ in v.drain(1..4) {} + assert_eq!(v, &[1.to_string(), 5.to_string()]); + + let mut v: ThinVec<_> = (1..6).map(|x| x.to_string()).collect(); + for _ in v.drain(1..4).rev() {} + assert_eq!(v, &[1.to_string(), 5.to_string()]); + + let mut v: ThinVec<_> = thin_vec![(); 5]; + for _ in v.drain(1..4).rev() {} + assert_eq!(v, &[(), ()]); + } + + #[test] + fn test_drain_inclusive_range() { + let mut v = thin_vec!['a', 'b', 'c', 'd', 'e']; + for _ in v.drain(1..=3) {} + assert_eq!(v, &['a', 'e']); + + let mut v: ThinVec<_> = (0..=5).map(|x| x.to_string()).collect(); + for _ in v.drain(1..=5) {} + assert_eq!(v, &["0".to_string()]); + + let mut v: ThinVec<String> = (0..=5).map(|x| x.to_string()).collect(); + for _ in v.drain(0..=5) {} + assert_eq!(v, ThinVec::<String>::new()); + + let mut v: ThinVec<_> = (0..=5).map(|x| x.to_string()).collect(); + for _ in v.drain(0..=3) {} + assert_eq!(v, &["4".to_string(), "5".to_string()]); + + let mut v: ThinVec<_> = (0..=1).map(|x| x.to_string()).collect(); + for _ in v.drain(..=0) {} + assert_eq!(v, &["1".to_string()]); + } + + #[test] + #[cfg(not(feature = "gecko-ffi"))] + fn test_drain_max_vec_size() { + let mut v = ThinVec::<()>::with_capacity(usize::max_value()); + unsafe { + v.set_len(usize::max_value()); + } + for _ in v.drain(usize::max_value() - 1..) {} + assert_eq!(v.len(), usize::max_value() - 1); + + let mut v = ThinVec::<()>::with_capacity(usize::max_value()); + unsafe { + v.set_len(usize::max_value()); + } + for _ in v.drain(usize::max_value() - 1..=usize::max_value() - 1) {} + assert_eq!(v.len(), usize::max_value() - 1); + } + + #[test] + #[should_panic] + fn test_drain_inclusive_out_of_bounds() { + let mut v = thin_vec![1, 2, 3, 4, 5]; + v.drain(5..=5); + } + + #[test] + fn test_splice() { + let mut v = thin_vec![1, 2, 3, 4, 5]; + let a = [10, 11, 12]; + v.splice(2..4, a.iter().cloned()); + assert_eq!(v, &[1, 2, 10, 11, 12, 5]); + v.splice(1..3, Some(20)); + assert_eq!(v, &[1, 20, 11, 12, 5]); + } + + #[test] + fn test_splice_inclusive_range() { + let mut v = thin_vec![1, 2, 3, 4, 5]; + let a = [10, 11, 12]; + let t1: ThinVec<_> = v.splice(2..=3, a.iter().cloned()).collect(); + assert_eq!(v, &[1, 2, 10, 11, 12, 5]); + assert_eq!(t1, &[3, 4]); + let t2: ThinVec<_> = v.splice(1..=2, Some(20)).collect(); + assert_eq!(v, &[1, 20, 11, 12, 5]); + assert_eq!(t2, &[2, 10]); + } + + #[test] + #[should_panic] + fn test_splice_out_of_bounds() { + let mut v = thin_vec![1, 2, 3, 4, 5]; + let a = [10, 11, 12]; + v.splice(5..6, a.iter().cloned()); + } + + #[test] + #[should_panic] + fn test_splice_inclusive_out_of_bounds() { + let mut v = thin_vec![1, 2, 3, 4, 5]; + let a = [10, 11, 12]; + v.splice(5..=5, a.iter().cloned()); + } + + #[test] + fn test_splice_items_zero_sized() { + let mut vec = thin_vec![(), (), ()]; + let vec2 = thin_vec![]; + let t: ThinVec<_> = vec.splice(1..2, vec2.iter().cloned()).collect(); + assert_eq!(vec, &[(), ()]); + assert_eq!(t, &[()]); + } + + #[test] + fn test_splice_unbounded() { + let mut vec = thin_vec![1, 2, 3, 4, 5]; + let t: ThinVec<_> = vec.splice(.., None).collect(); + assert_eq!(vec, &[]); + assert_eq!(t, &[1, 2, 3, 4, 5]); + } + + #[test] + fn test_splice_forget() { + let mut v = thin_vec![1, 2, 3, 4, 5]; + let a = [10, 11, 12]; + ::std::mem::forget(v.splice(2..4, a.iter().cloned())); + assert_eq!(v, &[1, 2]); + } + + #[test] + fn test_splice_from_empty() { + let mut v = thin_vec![]; + let a = [10, 11, 12]; + v.splice(.., a.iter().cloned()); + assert_eq!(v, &[10, 11, 12]); + } + + /* probs won't ever impl this + #[test] + fn test_into_boxed_slice() { + let xs = thin_vec![1, 2, 3]; + let ys = xs.into_boxed_slice(); + assert_eq!(&*ys, [1, 2, 3]); + } + */ + + #[test] + fn test_append() { + let mut vec = thin_vec![1, 2, 3]; + let mut vec2 = thin_vec![4, 5, 6]; + vec.append(&mut vec2); + assert_eq!(vec, [1, 2, 3, 4, 5, 6]); + assert_eq!(vec2, []); + } + + #[test] + fn test_split_off() { + let mut vec = thin_vec![1, 2, 3, 4, 5, 6]; + let vec2 = vec.split_off(4); + assert_eq!(vec, [1, 2, 3, 4]); + assert_eq!(vec2, [5, 6]); + } + + #[test] + fn test_into_iter_as_slice() { + let vec = thin_vec!['a', 'b', 'c']; + let mut into_iter = vec.into_iter(); + assert_eq!(into_iter.as_slice(), &['a', 'b', 'c']); + let _ = into_iter.next().unwrap(); + assert_eq!(into_iter.as_slice(), &['b', 'c']); + let _ = into_iter.next().unwrap(); + let _ = into_iter.next().unwrap(); + assert_eq!(into_iter.as_slice(), &[]); + } + + #[test] + fn test_into_iter_as_mut_slice() { + let vec = thin_vec!['a', 'b', 'c']; + let mut into_iter = vec.into_iter(); + assert_eq!(into_iter.as_slice(), &['a', 'b', 'c']); + into_iter.as_mut_slice()[0] = 'x'; + into_iter.as_mut_slice()[1] = 'y'; + assert_eq!(into_iter.next().unwrap(), 'x'); + assert_eq!(into_iter.as_slice(), &['y', 'c']); + } + + #[test] + fn test_into_iter_debug() { + let vec = thin_vec!['a', 'b', 'c']; + let into_iter = vec.into_iter(); + let debug = format!("{:?}", into_iter); + assert_eq!(debug, "IntoIter(['a', 'b', 'c'])"); + } + + #[test] + fn test_into_iter_count() { + assert_eq!(thin_vec![1, 2, 3].into_iter().count(), 3); + } + + #[test] + fn test_into_iter_clone() { + fn iter_equal<I: Iterator<Item = i32>>(it: I, slice: &[i32]) { + let v: ThinVec<i32> = it.collect(); + assert_eq!(&v[..], slice); + } + let mut it = thin_vec![1, 2, 3].into_iter(); + iter_equal(it.clone(), &[1, 2, 3]); + assert_eq!(it.next(), Some(1)); + let mut it = it.rev(); + iter_equal(it.clone(), &[3, 2]); + assert_eq!(it.next(), Some(3)); + iter_equal(it.clone(), &[2]); + assert_eq!(it.next(), Some(2)); + iter_equal(it.clone(), &[]); + assert_eq!(it.next(), None); + } + + /* TODO: make drain covariant + #[allow(dead_code)] + fn assert_covariance() { + fn drain<'new>(d: Drain<'static, &'static str>) -> Drain<'new, &'new str> { + d + } + fn into_iter<'new>(i: IntoIter<&'static str>) -> IntoIter<&'new str> { + i + } + } + */ + + /* TODO: specialize vec.into_iter().collect::<ThinVec<_>>(); + #[test] + fn from_into_inner() { + let vec = thin_vec![1, 2, 3]; + let ptr = vec.as_ptr(); + let vec = vec.into_iter().collect::<ThinVec<_>>(); + assert_eq!(vec, [1, 2, 3]); + assert_eq!(vec.as_ptr(), ptr); + + let ptr = &vec[1] as *const _; + let mut it = vec.into_iter(); + it.next().unwrap(); + let vec = it.collect::<ThinVec<_>>(); + assert_eq!(vec, [2, 3]); + assert!(ptr != vec.as_ptr()); + } + */ + + #[test] + #[cfg_attr(feature = "gecko-ffi", ignore)] + fn overaligned_allocations() { + #[repr(align(256))] + struct Foo(usize); + let mut v = thin_vec![Foo(273)]; + for i in 0..0x1000 { + v.reserve_exact(i); + assert!(v[0].0 == 273); + assert!(v.as_ptr() as usize & 0xff == 0); + v.shrink_to_fit(); + assert!(v[0].0 == 273); + assert!(v.as_ptr() as usize & 0xff == 0); + } + } + + /* TODO: implement drain_filter? + #[test] + fn drain_filter_empty() { + let mut vec: ThinVec<i32> = thin_vec![]; + + { + let mut iter = vec.drain_filter(|_| true); + assert_eq!(iter.size_hint(), (0, Some(0))); + assert_eq!(iter.next(), None); + assert_eq!(iter.size_hint(), (0, Some(0))); + assert_eq!(iter.next(), None); + assert_eq!(iter.size_hint(), (0, Some(0))); + } + assert_eq!(vec.len(), 0); + assert_eq!(vec, thin_vec![]); + } + + #[test] + fn drain_filter_zst() { + let mut vec = thin_vec![(), (), (), (), ()]; + let initial_len = vec.len(); + let mut count = 0; + { + let mut iter = vec.drain_filter(|_| true); + assert_eq!(iter.size_hint(), (0, Some(initial_len))); + while let Some(_) = iter.next() { + count += 1; + assert_eq!(iter.size_hint(), (0, Some(initial_len - count))); + } + assert_eq!(iter.size_hint(), (0, Some(0))); + assert_eq!(iter.next(), None); + assert_eq!(iter.size_hint(), (0, Some(0))); + } + + assert_eq!(count, initial_len); + assert_eq!(vec.len(), 0); + assert_eq!(vec, thin_vec![]); + } + + #[test] + fn drain_filter_false() { + let mut vec = thin_vec![1, 2, 3, 4, 5, 6, 7, 8, 9, 10]; + + let initial_len = vec.len(); + let mut count = 0; + { + let mut iter = vec.drain_filter(|_| false); + assert_eq!(iter.size_hint(), (0, Some(initial_len))); + for _ in iter.by_ref() { + count += 1; + } + assert_eq!(iter.size_hint(), (0, Some(0))); + assert_eq!(iter.next(), None); + assert_eq!(iter.size_hint(), (0, Some(0))); + } + + assert_eq!(count, 0); + assert_eq!(vec.len(), initial_len); + assert_eq!(vec, thin_vec![1, 2, 3, 4, 5, 6, 7, 8, 9, 10]); + } + + #[test] + fn drain_filter_true() { + let mut vec = thin_vec![1, 2, 3, 4, 5, 6, 7, 8, 9, 10]; + + let initial_len = vec.len(); + let mut count = 0; + { + let mut iter = vec.drain_filter(|_| true); + assert_eq!(iter.size_hint(), (0, Some(initial_len))); + while let Some(_) = iter.next() { + count += 1; + assert_eq!(iter.size_hint(), (0, Some(initial_len - count))); + } + assert_eq!(iter.size_hint(), (0, Some(0))); + assert_eq!(iter.next(), None); + assert_eq!(iter.size_hint(), (0, Some(0))); + } + + assert_eq!(count, initial_len); + assert_eq!(vec.len(), 0); + assert_eq!(vec, thin_vec![]); + } + + #[test] + fn drain_filter_complex() { + + { // [+xxx++++++xxxxx++++x+x++] + let mut vec = thin_vec![1, + 2, 4, 6, + 7, 9, 11, 13, 15, 17, + 18, 20, 22, 24, 26, + 27, 29, 31, 33, + 34, + 35, + 36, + 37, 39]; + + let removed = vec.drain_filter(|x| *x % 2 == 0).collect::<ThinVec<_>>(); + assert_eq!(removed.len(), 10); + assert_eq!(removed, thin_vec![2, 4, 6, 18, 20, 22, 24, 26, 34, 36]); + + assert_eq!(vec.len(), 14); + assert_eq!(vec, thin_vec![1, 7, 9, 11, 13, 15, 17, 27, 29, 31, 33, 35, 37, 39]); + } + + { // [xxx++++++xxxxx++++x+x++] + let mut vec = thin_vec![2, 4, 6, + 7, 9, 11, 13, 15, 17, + 18, 20, 22, 24, 26, + 27, 29, 31, 33, + 34, + 35, + 36, + 37, 39]; + + let removed = vec.drain_filter(|x| *x % 2 == 0).collect::<ThinVec<_>>(); + assert_eq!(removed.len(), 10); + assert_eq!(removed, thin_vec![2, 4, 6, 18, 20, 22, 24, 26, 34, 36]); + + assert_eq!(vec.len(), 13); + assert_eq!(vec, thin_vec![7, 9, 11, 13, 15, 17, 27, 29, 31, 33, 35, 37, 39]); + } + + { // [xxx++++++xxxxx++++x+x] + let mut vec = thin_vec![2, 4, 6, + 7, 9, 11, 13, 15, 17, + 18, 20, 22, 24, 26, + 27, 29, 31, 33, + 34, + 35, + 36]; + + let removed = vec.drain_filter(|x| *x % 2 == 0).collect::<ThinVec<_>>(); + assert_eq!(removed.len(), 10); + assert_eq!(removed, thin_vec![2, 4, 6, 18, 20, 22, 24, 26, 34, 36]); + + assert_eq!(vec.len(), 11); + assert_eq!(vec, thin_vec![7, 9, 11, 13, 15, 17, 27, 29, 31, 33, 35]); + } + + { // [xxxxxxxxxx+++++++++++] + let mut vec = thin_vec![2, 4, 6, 8, 10, 12, 14, 16, 18, 20, + 1, 3, 5, 7, 9, 11, 13, 15, 17, 19]; + + let removed = vec.drain_filter(|x| *x % 2 == 0).collect::<ThinVec<_>>(); + assert_eq!(removed.len(), 10); + assert_eq!(removed, thin_vec![2, 4, 6, 8, 10, 12, 14, 16, 18, 20]); + + assert_eq!(vec.len(), 10); + assert_eq!(vec, thin_vec![1, 3, 5, 7, 9, 11, 13, 15, 17, 19]); + } + + { // [+++++++++++xxxxxxxxxx] + let mut vec = thin_vec![1, 3, 5, 7, 9, 11, 13, 15, 17, 19, + 2, 4, 6, 8, 10, 12, 14, 16, 18, 20]; + + let removed = vec.drain_filter(|x| *x % 2 == 0).collect::<ThinVec<_>>(); + assert_eq!(removed.len(), 10); + assert_eq!(removed, thin_vec![2, 4, 6, 8, 10, 12, 14, 16, 18, 20]); + + assert_eq!(vec.len(), 10); + assert_eq!(vec, thin_vec![1, 3, 5, 7, 9, 11, 13, 15, 17, 19]); + } + } + */ + #[test] + fn test_reserve_exact() { + // This is all the same as test_reserve + + let mut v = ThinVec::new(); + assert_eq!(v.capacity(), 0); + + v.reserve_exact(2); + assert!(v.capacity() >= 2); + + for i in 0..16 { + v.push(i); + } + + assert!(v.capacity() >= 16); + v.reserve_exact(16); + assert!(v.capacity() >= 32); + + v.push(16); + + v.reserve_exact(16); + assert!(v.capacity() >= 33) + } + + /* TODO: implement try_reserve + #[test] + fn test_try_reserve() { + + // These are the interesting cases: + // * exactly isize::MAX should never trigger a CapacityOverflow (can be OOM) + // * > isize::MAX should always fail + // * On 16/32-bit should CapacityOverflow + // * On 64-bit should OOM + // * overflow may trigger when adding `len` to `cap` (in number of elements) + // * overflow may trigger when multiplying `new_cap` by size_of::<T> (to get bytes) + + const MAX_CAP: usize = isize::MAX as usize; + const MAX_USIZE: usize = usize::MAX; + + // On 16/32-bit, we check that allocations don't exceed isize::MAX, + // on 64-bit, we assume the OS will give an OOM for such a ridiculous size. + // Any platform that succeeds for these requests is technically broken with + // ptr::offset because LLVM is the worst. + let guards_against_isize = size_of::<usize>() < 8; + + { + // Note: basic stuff is checked by test_reserve + let mut empty_bytes: ThinVec<u8> = ThinVec::new(); + + // Check isize::MAX doesn't count as an overflow + if let Err(CapacityOverflow) = empty_bytes.try_reserve(MAX_CAP) { + panic!("isize::MAX shouldn't trigger an overflow!"); + } + // Play it again, frank! (just to be sure) + if let Err(CapacityOverflow) = empty_bytes.try_reserve(MAX_CAP) { + panic!("isize::MAX shouldn't trigger an overflow!"); + } + + if guards_against_isize { + // Check isize::MAX + 1 does count as overflow + if let Err(CapacityOverflow) = empty_bytes.try_reserve(MAX_CAP + 1) { + } else { panic!("isize::MAX + 1 should trigger an overflow!") } + + // Check usize::MAX does count as overflow + if let Err(CapacityOverflow) = empty_bytes.try_reserve(MAX_USIZE) { + } else { panic!("usize::MAX should trigger an overflow!") } + } else { + // Check isize::MAX + 1 is an OOM + if let Err(AllocErr) = empty_bytes.try_reserve(MAX_CAP + 1) { + } else { panic!("isize::MAX + 1 should trigger an OOM!") } + + // Check usize::MAX is an OOM + if let Err(AllocErr) = empty_bytes.try_reserve(MAX_USIZE) { + } else { panic!("usize::MAX should trigger an OOM!") } + } + } + + + { + // Same basic idea, but with non-zero len + let mut ten_bytes: ThinVec<u8> = thin_vec![1, 2, 3, 4, 5, 6, 7, 8, 9, 10]; + + if let Err(CapacityOverflow) = ten_bytes.try_reserve(MAX_CAP - 10) { + panic!("isize::MAX shouldn't trigger an overflow!"); + } + if let Err(CapacityOverflow) = ten_bytes.try_reserve(MAX_CAP - 10) { + panic!("isize::MAX shouldn't trigger an overflow!"); + } + if guards_against_isize { + if let Err(CapacityOverflow) = ten_bytes.try_reserve(MAX_CAP - 9) { + } else { panic!("isize::MAX + 1 should trigger an overflow!"); } + } else { + if let Err(AllocErr) = ten_bytes.try_reserve(MAX_CAP - 9) { + } else { panic!("isize::MAX + 1 should trigger an OOM!") } + } + // Should always overflow in the add-to-len + if let Err(CapacityOverflow) = ten_bytes.try_reserve(MAX_USIZE) { + } else { panic!("usize::MAX should trigger an overflow!") } + } + + + { + // Same basic idea, but with interesting type size + let mut ten_u32s: ThinVec<u32> = thin_vec![1, 2, 3, 4, 5, 6, 7, 8, 9, 10]; + + if let Err(CapacityOverflow) = ten_u32s.try_reserve(MAX_CAP/4 - 10) { + panic!("isize::MAX shouldn't trigger an overflow!"); + } + if let Err(CapacityOverflow) = ten_u32s.try_reserve(MAX_CAP/4 - 10) { + panic!("isize::MAX shouldn't trigger an overflow!"); + } + if guards_against_isize { + if let Err(CapacityOverflow) = ten_u32s.try_reserve(MAX_CAP/4 - 9) { + } else { panic!("isize::MAX + 1 should trigger an overflow!"); } + } else { + if let Err(AllocErr) = ten_u32s.try_reserve(MAX_CAP/4 - 9) { + } else { panic!("isize::MAX + 1 should trigger an OOM!") } + } + // Should fail in the mul-by-size + if let Err(CapacityOverflow) = ten_u32s.try_reserve(MAX_USIZE - 20) { + } else { + panic!("usize::MAX should trigger an overflow!"); + } + } + + } + + #[test] + fn test_try_reserve_exact() { + + // This is exactly the same as test_try_reserve with the method changed. + // See that test for comments. + + const MAX_CAP: usize = isize::MAX as usize; + const MAX_USIZE: usize = usize::MAX; + + let guards_against_isize = size_of::<usize>() < 8; + + { + let mut empty_bytes: ThinVec<u8> = ThinVec::new(); + + if let Err(CapacityOverflow) = empty_bytes.try_reserve_exact(MAX_CAP) { + panic!("isize::MAX shouldn't trigger an overflow!"); + } + if let Err(CapacityOverflow) = empty_bytes.try_reserve_exact(MAX_CAP) { + panic!("isize::MAX shouldn't trigger an overflow!"); + } + + if guards_against_isize { + if let Err(CapacityOverflow) = empty_bytes.try_reserve_exact(MAX_CAP + 1) { + } else { panic!("isize::MAX + 1 should trigger an overflow!") } + + if let Err(CapacityOverflow) = empty_bytes.try_reserve_exact(MAX_USIZE) { + } else { panic!("usize::MAX should trigger an overflow!") } + } else { + if let Err(AllocErr) = empty_bytes.try_reserve_exact(MAX_CAP + 1) { + } else { panic!("isize::MAX + 1 should trigger an OOM!") } + + if let Err(AllocErr) = empty_bytes.try_reserve_exact(MAX_USIZE) { + } else { panic!("usize::MAX should trigger an OOM!") } + } + } + + + { + let mut ten_bytes: ThinVec<u8> = thin_vec![1, 2, 3, 4, 5, 6, 7, 8, 9, 10]; + + if let Err(CapacityOverflow) = ten_bytes.try_reserve_exact(MAX_CAP - 10) { + panic!("isize::MAX shouldn't trigger an overflow!"); + } + if let Err(CapacityOverflow) = ten_bytes.try_reserve_exact(MAX_CAP - 10) { + panic!("isize::MAX shouldn't trigger an overflow!"); + } + if guards_against_isize { + if let Err(CapacityOverflow) = ten_bytes.try_reserve_exact(MAX_CAP - 9) { + } else { panic!("isize::MAX + 1 should trigger an overflow!"); } + } else { + if let Err(AllocErr) = ten_bytes.try_reserve_exact(MAX_CAP - 9) { + } else { panic!("isize::MAX + 1 should trigger an OOM!") } + } + if let Err(CapacityOverflow) = ten_bytes.try_reserve_exact(MAX_USIZE) { + } else { panic!("usize::MAX should trigger an overflow!") } + } + + + { + let mut ten_u32s: ThinVec<u32> = thin_vec![1, 2, 3, 4, 5, 6, 7, 8, 9, 10]; + + if let Err(CapacityOverflow) = ten_u32s.try_reserve_exact(MAX_CAP/4 - 10) { + panic!("isize::MAX shouldn't trigger an overflow!"); + } + if let Err(CapacityOverflow) = ten_u32s.try_reserve_exact(MAX_CAP/4 - 10) { + panic!("isize::MAX shouldn't trigger an overflow!"); + } + if guards_against_isize { + if let Err(CapacityOverflow) = ten_u32s.try_reserve_exact(MAX_CAP/4 - 9) { + } else { panic!("isize::MAX + 1 should trigger an overflow!"); } + } else { + if let Err(AllocErr) = ten_u32s.try_reserve_exact(MAX_CAP/4 - 9) { + } else { panic!("isize::MAX + 1 should trigger an OOM!") } + } + if let Err(CapacityOverflow) = ten_u32s.try_reserve_exact(MAX_USIZE - 20) { + } else { panic!("usize::MAX should trigger an overflow!") } + } + } + */ + + #[test] + #[cfg_attr(feature = "gecko-ffi", ignore)] + fn test_header_data() { + macro_rules! assert_aligned_head_ptr { + ($typename:ty) => {{ + let v: ThinVec<$typename> = ThinVec::with_capacity(1 /* ensure allocation */); + let head_ptr: *mut $typename = v.data_raw(); + assert_eq!( + head_ptr as usize % std::mem::align_of::<$typename>(), + 0, + "expected Header::data<{}> to be aligned", + stringify!($typename) + ); + }}; + } + + const HEADER_SIZE: usize = std::mem::size_of::<Header>(); + assert_eq!(2 * std::mem::size_of::<usize>(), HEADER_SIZE); + + #[repr(C, align(128))] + struct Funky<T>(T); + assert_eq!(padding::<Funky<()>>(), 128 - HEADER_SIZE); + assert_aligned_head_ptr!(Funky<()>); + + assert_eq!(padding::<Funky<u8>>(), 128 - HEADER_SIZE); + assert_aligned_head_ptr!(Funky<u8>); + + assert_eq!(padding::<Funky<[(); 1024]>>(), 128 - HEADER_SIZE); + assert_aligned_head_ptr!(Funky<[(); 1024]>); + + assert_eq!(padding::<Funky<[*mut usize; 1024]>>(), 128 - HEADER_SIZE); + assert_aligned_head_ptr!(Funky<[*mut usize; 1024]>); + } + + #[cfg(feature = "serde")] + use serde_test::{assert_tokens, Token}; + + #[test] + #[cfg(feature = "serde")] + fn test_ser_de_empty() { + let vec = ThinVec::<u32>::new(); + + assert_tokens(&vec, &[Token::Seq { len: Some(0) }, Token::SeqEnd]); + } + + #[test] + #[cfg(feature = "serde")] + fn test_ser_de() { + let mut vec = ThinVec::<u32>::new(); + vec.push(20); + vec.push(55); + vec.push(123); + + assert_tokens( + &vec, + &[ + Token::Seq { len: Some(3) }, + Token::U32(20), + Token::U32(55), + Token::U32(123), + Token::SeqEnd, + ], + ); + } + + #[test] + fn test_set_len() { + let mut vec: ThinVec<u32> = thin_vec![]; + unsafe { + vec.set_len(0); // at one point this caused a crash + } + } + + #[test] + #[should_panic(expected = "invalid set_len(1) on empty ThinVec")] + fn test_set_len_invalid() { + let mut vec: ThinVec<u32> = thin_vec![]; + unsafe { + vec.set_len(1); + } + } + + #[test] + #[should_panic(expected = "capacity overflow")] + fn test_capacity_overflow_header_too_big() { + let vec: ThinVec<u8> = ThinVec::with_capacity(isize::MAX as usize - 2); + assert!(vec.capacity() > 0); + } + #[test] + #[should_panic(expected = "capacity overflow")] + fn test_capacity_overflow_cap_too_big() { + let vec: ThinVec<u8> = ThinVec::with_capacity(isize::MAX as usize + 1); + assert!(vec.capacity() > 0); + } + #[test] + #[should_panic(expected = "capacity overflow")] + fn test_capacity_overflow_size_mul1() { + let vec: ThinVec<u16> = ThinVec::with_capacity(isize::MAX as usize + 1); + assert!(vec.capacity() > 0); + } + #[test] + #[should_panic(expected = "capacity overflow")] + fn test_capacity_overflow_size_mul2() { + let vec: ThinVec<u16> = ThinVec::with_capacity(isize::MAX as usize / 2 + 1); + assert!(vec.capacity() > 0); + } + #[test] + #[should_panic(expected = "capacity overflow")] + fn test_capacity_overflow_cap_really_isnt_isize() { + let vec: ThinVec<u8> = ThinVec::with_capacity(isize::MAX as usize); + assert!(vec.capacity() > 0); + } +} |