Auto merge of rust-lang#546 - Amanieu:remove-raw, r=Amanieu

Remove the `raw` feature and make `RawTable` private

This will give more freedom for the internal implementation details of hashbrown to evolve without the need for regular releases with breaking changes.

All existing users of `RawTable` should migrate to the `HashTable` API which is entirely safe while providing the same flexibility as `RawTable`.

This also removes the following features which were only exposed under `RawTable`:
- `RawTable::iter_hash`
- `RawIter::reflect_insert` and `RawIter::reflect_remove`
- `RawTable::clone_from_with_hasher`
- `RawTable::insert_no_grow` and `RawTable::try_insert_no_grow`
- `RawTable::allocation_info`
- `RawTable::try_with_capacity(_in)`
- `HashMap::raw_table(_mut)` and `HashSet::raw_table(_mut)`

If anyone was previously relying on this functionaly, please raise a comment. It may be possible to re-introduce it as a safe API in `HashTable` and/or `HashMap`.

Author: bors

Cargo.toml

@@ -67,9 +67,6 @@ rustc-dep-of-std = [
     "raw-entry",
 ]
 
-# Enables the experimental and unsafe RawTable API.
-raw = []
-
 # Enables the deprecated RawEntry API.
 raw-entry = []
 
@@ -84,5 +81,5 @@ default-hasher = ["dep:ahash"]
 inline-more = []
 
 [package.metadata.docs.rs]
-features = ["nightly", "rayon", "serde", "raw"]
+features = ["nightly", "rayon", "serde", "raw-entry"]
 rustdoc-args = ["--generate-link-to-definition"]

README.md

@@ -105,7 +105,6 @@ This crate has the following Cargo features:
 - `rkyv`: Enables rkyv serialization support.
 - `rayon`: Enables rayon parallel iterator support.
 - `equivalent`: Allows comparisons to be customized with the `Equivalent` trait.
-- `raw`: Enables access to the experimental and unsafe `RawTable` API.
 - `raw-entry`: Enables access to the deprecated `RawEntry` API.
 - `inline-more`: Adds inline hints to most functions, improving run-time performance at the cost
   of compilation time. (enabled by default)

ci/run.sh

@@ -33,7 +33,7 @@ if [ "${NO_STD}" = "1" ]; then
     FEATURES="rustc-internal-api"
     OP="build"
 else
-    FEATURES="rustc-internal-api,serde,rayon,raw"
+    FEATURES="rustc-internal-api,serde,rayon"
     OP="test"
 fi
 

ci/tools.sh

@@ -31,7 +31,6 @@ fi
 
 if retry rustup component add clippy ; then
     cargo clippy --all --tests --features serde,rayon -- -D clippy::all
-    cargo clippy --all --tests --features raw -- -D clippy::all
 fi
 
 if command -v shellcheck ; then

src/lib.rs

@@ -61,27 +61,6 @@ doc_comment::doctest!("../README.md");
 #[macro_use]
 mod macros;
 
-#[cfg(feature = "raw")]
-/// Experimental and unsafe `RawTable` API. This module is only available if the
-/// `raw` feature is enabled.
-pub mod raw {
-    // The RawTable API is still experimental and is not properly documented yet.
-    #[allow(missing_docs)]
-    #[path = "mod.rs"]
-    mod inner;
-    pub use inner::*;
-
-    #[cfg(feature = "rayon")]
-    /// [rayon]-based parallel iterator types for hash maps.
-    /// You will rarely need to interact with it directly unless you have need
-    /// to name one of the iterator types.
-    ///
-    /// [rayon]: https://docs.rs/rayon/1.0/rayon
-    pub mod rayon {
-        pub use crate::external_trait_impls::rayon::raw::*;
-    }
-}
-#[cfg(not(feature = "raw"))]
 mod raw;
 
 mod external_trait_impls;

src/map.rs

@@ -1931,81 +1931,6 @@ where
     }
 }
 
-impl<K, V, S, A: Allocator> HashMap<K, V, S, A> {
-    /// Returns a reference to the [`RawTable`] used underneath [`HashMap`].
-    /// This function is only available if the `raw` feature of the crate is enabled.
-    ///
-    /// See [`raw_table_mut`] for more.
-    ///
-    /// [`raw_table_mut`]: Self::raw_table_mut
-    #[cfg(feature = "raw")]
-    #[cfg_attr(feature = "inline-more", inline)]
-    pub fn raw_table(&self) -> &RawTable<(K, V), A> {
-        &self.table
-    }
-
-    /// Returns a mutable reference to the [`RawTable`] used underneath [`HashMap`].
-    /// This function is only available if the `raw` feature of the crate is enabled.
-    ///
-    /// # Note
-    ///
-    /// Calling this function is safe, but using the raw hash table API may require
-    /// unsafe functions or blocks.
-    ///
-    /// `RawTable` API gives the lowest level of control under the map that can be useful
-    /// for extending the HashMap's API, but may lead to *[undefined behavior]*.
-    ///
-    /// [`HashMap`]: struct.HashMap.html
-    /// [`RawTable`]: crate::raw::RawTable
-    /// [undefined behavior]: https://doc.rust-lang.org/reference/behavior-considered-undefined.html
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// use core::hash::{BuildHasher, Hash};
-    /// use hashbrown::HashMap;
-    ///
-    /// let mut map = HashMap::new();
-    /// map.extend([("a", 10), ("b", 20), ("c", 30)]);
-    /// assert_eq!(map.len(), 3);
-    ///
-    /// // Let's imagine that we have a value and a hash of the key, but not the key itself.
-    /// // However, if you want to remove the value from the map by hash and value, and you
-    /// // know exactly that the value is unique, then you can create a function like this:
-    /// fn remove_by_hash<K, V, S, F>(
-    ///     map: &mut HashMap<K, V, S>,
-    ///     hash: u64,
-    ///     is_match: F,
-    /// ) -> Option<(K, V)>
-    /// where
-    ///     F: Fn(&(K, V)) -> bool,
-    /// {
-    ///     let raw_table = map.raw_table_mut();
-    ///     match raw_table.find(hash, is_match) {
-    ///         Some(bucket) => Some(unsafe { raw_table.remove(bucket).0 }),
-    ///         None => None,
-    ///     }
-    /// }
-    ///
-    /// fn compute_hash<K: Hash + ?Sized, S: BuildHasher>(hash_builder: &S, key: &K) -> u64 {
-    ///     use core::hash::Hasher;
-    ///     let mut state = hash_builder.build_hasher();
-    ///     key.hash(&mut state);
-    ///     state.finish()
-    /// }
-    ///
-    /// let hash = compute_hash(map.hasher(), "a");
-    /// assert_eq!(remove_by_hash(&mut map, hash, |(_, v)| *v == 10), Some(("a", 10)));
-    /// assert_eq!(map.get(&"a"), None);
-    /// assert_eq!(map.len(), 2);
-    /// ```
-    #[cfg(feature = "raw")]
-    #[cfg_attr(feature = "inline-more", inline)]
-    pub fn raw_table_mut(&mut self) -> &mut RawTable<(K, V), A> {
-        &mut self.table
-    }
-}
-
 impl<K, V, S, A> PartialEq for HashMap<K, V, S, A>
 where
     K: Eq + Hash,
@@ -5958,74 +5883,6 @@ mod test_map {
         }
     }
 
-    #[test]
-    #[cfg(feature = "raw")]
-    fn test_into_iter_refresh() {
-        #[cfg(miri)]
-        const N: usize = 32;
-        #[cfg(not(miri))]
-        const N: usize = 128;
-
-        let mut rng = rand::thread_rng();
-        for n in 0..N {
-            let mut map = HashMap::new();
-            for i in 0..n {
-                assert!(map.insert(i, 2 * i).is_none());
-            }
-            let hash_builder = map.hasher().clone();
-
-            let mut it = unsafe { map.table.iter() };
-            assert_eq!(it.len(), n);
-
-            let mut i = 0;
-            let mut left = n;
-            let mut removed = Vec::new();
-            loop {
-                // occasionally remove some elements
-                if i < n && rng.gen_bool(0.1) {
-                    let hash_value = super::make_hash(&hash_builder, &i);
-
-                    unsafe {
-                        let e = map.table.find(hash_value, |q| q.0.eq(&i));
-                        if let Some(e) = e {
-                            it.reflect_remove(&e);
-                            let t = map.table.remove(e).0;
-                            removed.push(t);
-                            left -= 1;
-                        } else {
-                            assert!(removed.contains(&(i, 2 * i)), "{i} not in {removed:?}");
-                            let e = map.table.insert(
-                                hash_value,
-                                (i, 2 * i),
-                                super::make_hasher::<_, usize, _>(&hash_builder),
-                            );
-                            it.reflect_insert(&e);
-                            if let Some(p) = removed.iter().position(|e| e == &(i, 2 * i)) {
-                                removed.swap_remove(p);
-                            }
-                            left += 1;
-                        }
-                    }
-                }
-
-                let e = it.next();
-                if e.is_none() {
-                    break;
-                }
-                assert!(i < n);
-                let t = unsafe { e.unwrap().as_ref() };
-                assert!(!removed.contains(t));
-                let (key, value) = t;
-                assert_eq!(*value, 2 * key);
-                i += 1;
-            }
-            assert!(i <= n);
-
-            // just for safety:
-            assert_eq!(map.table.len(), left);
-        }
-    }
-
     #[test]
     fn test_const_with_hasher() {
         use core::hash::BuildHasher;

src/raw/bitmask.rs

@@ -105,22 +105,6 @@ impl IntoIterator for BitMask {
 #[derive(Copy, Clone)]
 pub(crate) struct BitMaskIter(pub(crate) BitMask);
 
-impl BitMaskIter {
-    /// Flip the bit in the mask for the entry at the given index.
-    ///
-    /// Returns the bit's previous state.
-    #[inline]
-    #[allow(clippy::cast_ptr_alignment)]
-    #[cfg(feature = "raw")]
-    pub(crate) unsafe fn flip(&mut self, index: usize) -> bool {
-        // NOTE: The + BITMASK_STRIDE - 1 is to set the high bit.
-        let mask = 1 << (index * BITMASK_STRIDE + BITMASK_STRIDE - 1);
-        self.0 .0 ^= mask;
-        // The bit was set if the bit is now 0.
-        self.0 .0 & mask == 0
-    }
-}
-
 impl Iterator for BitMaskIter {
     type Item = usize;