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Merge pull request #3696 from youknowone/dict

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Remove DictInner::next_new_entry_idx and IndexEntry as a shallow wrapper of i64
This commit is contained in:
Jeong YunWon
2022-05-18 11:13:08 +09:00
committed by GitHub
parent aa100841a7 25a6629742
commit 1cb692547e
1 changed files with 87 additions and 74 deletions
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161
vm/src/dictdatatype.rs
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@@ -37,34 +37,26 @@ impl<T> fmt::Debug for Dict<T> {
}
}
#[derive(Debug, Copy, Clone)]
enum IndexEntry {
Dummy,
Free,
Index(usize),
}
#[derive(Debug, Copy, Clone, PartialEq, Eq)]
#[repr(transparent)]
struct IndexEntry(i64);
impl IndexEntry {
const FREE: i64 = -1;
const DUMMY: i64 = -2;
}
const FREE: Self = Self(-1);
const DUMMY: Self = Self(-2);
impl From<i64> for IndexEntry {
fn from(idx: i64) -> Self {
match idx {
IndexEntry::FREE => IndexEntry::Free,
IndexEntry::DUMMY => IndexEntry::Dummy,
x => IndexEntry::Index(x as usize),
}
/// # Safety
/// idx must not be one of FREE or DUMMY
unsafe fn from_index_unchecked(idx: usize) -> Self {
debug_assert!((idx as isize) >= 0);
Self(idx as i64)
}
}
impl From<IndexEntry> for i64 {
fn from(idx: IndexEntry) -> Self {
match idx {
IndexEntry::Free => IndexEntry::FREE,
IndexEntry::Dummy => IndexEntry::DUMMY,
IndexEntry::Index(i) => i as i64,
fn index(self) -> Option<usize> {
if self.0 >= 0 {
Some(self.0 as usize)
} else {
None
}
}
}
@@ -73,10 +65,8 @@ impl From<IndexEntry> for i64 {
struct DictInner<T> {
used: usize,
filled: usize,
indices: Vec<i64>,
indices: Vec<IndexEntry>,
entries: Vec<Option<DictEntry<T>>>,
// index to new inserted element should be in entries
next_new_entry_idx: usize,
}
impl<T: Clone> Clone for Dict<T> {
@@ -95,7 +85,6 @@ impl<T> Default for Dict<T> {
filled: 0,
indices: vec![IndexEntry::FREE; 8],
entries: Vec::new(),
next_new_entry_idx: 0,
}),
}
}
@@ -108,6 +97,7 @@ struct DictEntry<T> {
index: IndexIndex,
value: T,
}
static_assertions::assert_eq_size!(DictEntry<PyObjectRef>, Option<DictEntry<PyObjectRef>>);
impl<T: Clone> DictEntry<T> {
pub(crate) fn as_tuple(&self) -> (PyObjectRef, T) {
@@ -175,11 +165,16 @@ impl<T> DictInner<T> {
let mut idxs = GenIndexes::new(entry.hash, mask);
loop {
let index_index = idxs.next();
let idx = &mut self.indices[index_index];
if *idx == IndexEntry::FREE {
*idx = entry_idx as i64;
entry.index = index_index;
break;
unsafe {
// Safety: index is always valid here
// index_index is generated by idxs
// entry_idx is saved one
let idx = self.indices.get_unchecked_mut(index_index);
if *idx == IndexEntry::FREE {
*idx = IndexEntry::from_index_unchecked(entry_idx);
entry.index = index_index;
break;
}
}
}
} else {
@@ -187,7 +182,6 @@ impl<T> DictInner<T> {
}
}
self.filled = self.used;
self.next_new_entry_idx = self.entries.len();
}
fn unchecked_push(
@@ -204,16 +198,15 @@ impl<T> DictInner<T> {
value,
index,
};
let entry_index = self.next_new_entry_idx;
if self.entries.len() == entry_index {
self.entries.push(Some(entry));
} else {
self.entries[entry_index] = Some(entry);
}
self.indices[index] = entry_index as i64;
let entry_index = self.entries.len();
self.entries.push(Some(entry));
self.indices[index] = unsafe {
// SAFETY: entry_index is self.entries.len(). it never can
// grow to `usize-2` because hash tables cannot full its index
IndexEntry::from_index_unchecked(entry_index)
};
self.used += 1;
self.next_new_entry_idx += 1;
if let IndexEntry::Free = index_entry {
if let IndexEntry::FREE = index_entry {
self.filled += 1;
if let Some(new_size) = self.should_resize() {
self.resize(new_size)
@@ -260,7 +253,7 @@ impl<T: Clone> Dict<T> {
let _removed = loop {
let (entry_index, index_index) = self.lookup(vm, key, hash, None)?;
let mut inner = self.write();
if let IndexEntry::Index(index) = entry_index {
if let Some(index) = entry_index.index() {
// Update existing key
if let Some(entry) = inner.entries.get_mut(index) {
let entry = entry
@@ -287,7 +280,7 @@ impl<T: Clone> Dict<T> {
pub fn contains<K: DictKey + ?Sized>(&self, vm: &VirtualMachine, key: &K) -> PyResult<bool> {
let (entry, _) = self.lookup(vm, key, key.key_hash(vm)?, None)?;
Ok(matches!(entry, IndexEntry::Index(_)))
Ok(entry.index().is_some())
}
/// Retrieve a key
@@ -305,7 +298,7 @@ impl<T: Clone> Dict<T> {
) -> PyResult<Option<T>> {
let ret = loop {
let (entry, index_index) = self.lookup(vm, key, hash, None)?;
if let IndexEntry::Index(index) = entry {
if let Some(index) = entry.index() {
let inner = self.read();
if let Some(entry) = inner.entries.get(index) {
let entry = extract_dict_entry(entry);
@@ -346,7 +339,6 @@ impl<T: Clone> Dict<T> {
inner.indices.resize(8, IndexEntry::FREE);
inner.used = 0;
inner.filled = 0;
inner.next_new_entry_idx = 0;
// defer dec rc
std::mem::take(&mut inner.entries)
};
@@ -394,7 +386,7 @@ impl<T: Clone> Dict<T> {
let _removed = loop {
let lookup = self.lookup(vm, key, hash, None)?;
let (entry, index_index) = lookup;
if let IndexEntry::Index(_) = entry {
if entry.index().is_some() {
match self.pop_inner(lookup) {
ControlFlow::Break(Some(entry)) => break Some(entry),
_ => continue,
@@ -416,8 +408,8 @@ impl<T: Clone> Dict<T> {
let hash = key.key_hash(vm)?;
let res = loop {
let lookup = self.lookup(vm, key, hash, None)?;
let (entry, index_index) = lookup;
if let IndexEntry::Index(index) = entry {
let (index_entry, index_index) = lookup;
if let Some(index) = index_entry.index() {
let inner = self.read();
if let Some(entry) = inner.entries.get(index) {
let entry = extract_dict_entry(entry);
@@ -433,7 +425,13 @@ impl<T: Clone> Dict<T> {
} else {
let value = default();
let mut inner = self.write();
inner.unchecked_push(index_index, hash, key.to_pyobject(vm), value.clone(), entry);
inner.unchecked_push(
index_index,
hash,
key.to_pyobject(vm),
value.clone(),
index_entry,
);
break value;
}
};
@@ -454,8 +452,8 @@ impl<T: Clone> Dict<T> {
let hash = key.key_hash(vm)?;
let res = loop {
let lookup = self.lookup(vm, key, hash, None)?;
let (entry, index_index) = lookup;
if let IndexEntry::Index(index) = entry {
let (index_entry, index_index) = lookup;
if let Some(index) = index_entry.index() {
let inner = self.read();
if let Some(entry) = inner.entries.get(index) {
let entry = extract_dict_entry(entry);
@@ -473,7 +471,7 @@ impl<T: Clone> Dict<T> {
let key = key.to_pyobject(vm);
let mut inner = self.write();
let ret = (key.clone(), value.clone());
inner.unchecked_push(index_index, hash, key, value, entry);
inner.unchecked_push(index_index, hash, key, value, index_entry);
break ret;
}
};
@@ -541,7 +539,7 @@ impl<T: Clone> Dict<T> {
mut lock: Option<PyRwLockReadGuard<DictInner<T>>>,
) -> PyResult<LookupResult> {
let mut idxs = None;
let mut freeslot = None;
let mut free_slot = None;
let ret = 'outer: loop {
let (entry_key, ret) = {
let inner = lock.take().unwrap_or_else(|| self.read());
@@ -550,22 +548,31 @@ impl<T: Clone> Dict<T> {
});
loop {
let index_index = idxs.next();
match IndexEntry::from(inner.indices[index_index]) {
IndexEntry::Dummy => {
if freeslot.is_none() {
freeslot = Some(index_index);
let index_entry = *unsafe {
// Safety: index_index is generated
inner.indices.get_unchecked(index_index)
};
match index_entry {
IndexEntry::DUMMY => {
if free_slot.is_none() {
free_slot = Some(index_index);
}
}
IndexEntry::Free => {
let idxs = match freeslot {
Some(free) => (IndexEntry::Dummy, free),
None => (IndexEntry::Free, index_index),
IndexEntry::FREE => {
let idxs = match free_slot {
Some(free) => (IndexEntry::DUMMY, free),
None => (IndexEntry::FREE, index_index),
};
return Ok(idxs);
}
IndexEntry::Index(i) => {
let entry = &inner.entries[i].as_ref().unwrap();
let ret = (IndexEntry::Index(i), index_index);
idx => {
let entry = unsafe {
// Safety: DUMMY and FREE are already handled above.
// i is always valid and entry always exists.
let i = idx.index().unwrap_unchecked();
inner.entries.get_unchecked(i).as_ref().unwrap_unchecked()
};
let ret = (idx, index_index);
if key.key_is(&entry.key) {
break 'outer ret;
} else if entry.hash == hash_value {
@@ -602,7 +609,7 @@ impl<T: Clone> Dict<T> {
pred: impl Fn(&T) -> Result<bool, E>,
) -> Result<PopInnerResult<T>, E> {
let (entry_index, index_index) = lookup;
let entry_index = if let IndexEntry::Index(entry_index) = entry_index {
let entry_index = if let Some(entry_index) = entry_index.index() {
entry_index
} else {
return Ok(ControlFlow::Break(None));
@@ -623,7 +630,10 @@ impl<T: Clone> Dict<T> {
// The dict was changed since we did lookup. Let's try again.
_ => return Ok(ControlFlow::Continue(())),
}
inner.indices[index_index] = IndexEntry::DUMMY;
*unsafe {
// index_index is result of lookup
inner.indices.get_unchecked_mut(index_index)
} = IndexEntry::DUMMY;
inner.used -= 1;
let removed = slot.take();
Ok(ControlFlow::Break(removed))
@@ -644,14 +654,17 @@ impl<T: Clone> Dict<T> {
pub fn pop_back(&self) -> Option<(PyObjectRef, T)> {
let mut inner = &mut *self.write();
let (entry_idx, entry) = inner.entries[..inner.next_new_entry_idx]
.iter_mut()
.enumerate()
.rev()
.find_map(|(i, entry)| entry.take().map(|e| (i, e)))?;
let entry = loop {
let entry = inner.entries.pop()?;
if let Some(entry) = entry {
break entry;
}
};
inner.used -= 1;
inner.indices[entry.index] = IndexEntry::DUMMY;
inner.next_new_entry_idx = entry_idx;
*unsafe {
// entry.index always refers valid index
inner.indices.get_unchecked_mut(entry.index)
} = IndexEntry::DUMMY;
Some((entry.key, entry.value))
}