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Clean up some usages of LowLevelList<T> (#105407)
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@huoyaoyuan
huoyaoyuan authored Jul 26, 2024
1 parent 8e3896b commit 5940292
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352 changes: 0 additions & 352 deletions src/coreclr/nativeaot/Common/src/System/Collections/Generic/LowLevelList.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -31,7 +31,6 @@ namespace System.Collections.Generic
// LowLevelList with no interface implementation minimizes both code and data size.
// Data size is smaller because there will be minimal virtual function table.
// Code size is smaller because only functions called will be in the binary.
// Use LowLevelListWithIList<T> for IList support
[DebuggerDisplay("Count = {Count}")]
#if TYPE_LOADER_IMPLEMENTATION
[System.Runtime.CompilerServices.ForceDictionaryLookups]
Expand Down Expand Up @@ -196,356 +195,5 @@ private void EnsureCapacity(int min)
Capacity = newCapacity;
}
}

#if !TYPE_LOADER_IMPLEMENTATION
// Adds the elements of the given collection to the end of this list. If
// required, the capacity of the list is increased to twice the previous
// capacity or the new size, whichever is larger.
//
public void AddRange(IEnumerable<T> collection)
{

InsertRange(_size, collection);
}

// Clears the contents of List.
public void Clear()
{
if (_size > 0)
{
Array.Clear(_items, 0, _size); // Don't need to doc this but we clear the elements so that the gc can reclaim the references.
_size = 0;
}
_version++;
}

// Contains returns true if the specified element is in the List.
// It does a linear, O(n) search. Equality is determined by calling
// item.Equals().
//
public bool Contains(T item)
{
if ((object?)item == null)
{
for (int i = 0; i < _size; i++)
if ((object?)_items[i] == null)
return true;
return false;
}
else
{
int index = IndexOf(item);
if (index >= 0)
return true;
return false;
}
}


// Copies a section of this list to the given array at the given index.
//
// The method uses the Array.Copy method to copy the elements.
//
public void CopyTo(int index, T[] array, int arrayIndex, int count)
{
if (_size - index < count)
{
throw new ArgumentException();
}

// Delegate rest of error checking to Array.Copy.
Array.Copy(_items, index, array, arrayIndex, count);
}

public void CopyTo(T[] array, int arrayIndex)
{
// Delegate rest of error checking to Array.Copy.
Array.Copy(_items, 0, array, arrayIndex, _size);
}

// Returns the index of the first occurrence of a given value in a range of
// this list. The list is searched forwards from beginning to end.
// The elements of the list are compared to the given value using the
// Object.Equals method.
//
// This method uses the Array.IndexOf method to perform the
// search.
//
public int IndexOf(T item)
{
return Array.IndexOf(_items, item, 0, _size);
}


// Returns the index of the first occurrence of a given value in a range of
// this list. The list is searched forwards, starting at index
// index and ending at count number of elements. The
// elements of the list are compared to the given value using the
// Object.Equals method.
//
// This method uses the Array.IndexOf method to perform the
// search.
//
public int IndexOf(T item, int index)
{
ArgumentOutOfRangeException.ThrowIfGreaterThan(index, _size);
return Array.IndexOf(_items, item, index, _size - index);
}

// Inserts an element into this list at a given index. The size of the list
// is increased by one. If required, the capacity of the list is doubled
// before inserting the new element.
//
public void Insert(int index, T item)
{
// Note that insertions at the end are legal.
ArgumentOutOfRangeException.ThrowIfGreaterThan((uint)index, (uint)_size, nameof(index));

if (_size == _items.Length) EnsureCapacity(_size + 1);
if (index < _size)
{
Array.Copy(_items, index, _items, index + 1, _size - index);
}
_items[index] = item;
_size++;
_version++;
}

// Inserts the elements of the given collection at a given index. If
// required, the capacity of the list is increased to twice the previous
// capacity or the new size, whichever is larger. Ranges may be added
// to the end of the list by setting index to the List's size.
//
public void InsertRange(int index, IEnumerable<T> collection)
{
ArgumentNullException.ThrowIfNull(collection);
ArgumentOutOfRangeException.ThrowIfGreaterThan((uint)index, (uint)_size, nameof(index));

ICollection<T>? c = collection as ICollection<T>;
if (c != null)
{ // if collection is ICollection<T>
int count = c.Count;
if (count > 0)
{
EnsureCapacity(_size + count);
if (index < _size)
{
Array.Copy(_items, index, _items, index + count, _size - index);
}

// If we're inserting a List into itself, we want to be able to deal with that.
if (this == c)
{
// Copy first part of _items to insert location
Array.Copy(_items, 0, _items, index, index);
// Copy last part of _items back to inserted location
Array.Copy(_items, index + count, _items, index * 2, _size - index);
}
else
{
T[] itemsToInsert = new T[count];
c.CopyTo(itemsToInsert, 0);
Array.Copy(itemsToInsert, 0, _items, index, count);
}
_size += count;
}
}
else
{
using (IEnumerator<T> en = collection.GetEnumerator())
{
while (en.MoveNext())
{
Insert(index++, en.Current);
}
}
}
_version++;
}

// Removes the element at the given index. The size of the list is
// decreased by one.
//
public bool Remove(T item)
{
int index = IndexOf(item);
if (index >= 0)
{
RemoveAt(index);
return true;
}

return false;
}

// This method removes all items which matches the predicate.
// The complexity is O(n).
public int RemoveAll(Predicate<T> match)
{
ArgumentNullException.ThrowIfNull(match);

int freeIndex = 0; // the first free slot in items array

// Find the first item which needs to be removed.
while (freeIndex < _size && !match(_items[freeIndex]!)) freeIndex++;
if (freeIndex >= _size) return 0;

int current = freeIndex + 1;
while (current < _size)
{
// Find the first item which needs to be kept.
while (current < _size && match(_items[current]!)) current++;

if (current < _size)
{
// copy item to the free slot.
_items[freeIndex++] = _items[current++];
}
}

Array.Clear(_items, freeIndex, _size - freeIndex);
int result = _size - freeIndex;
_size = freeIndex;
_version++;
return result;
}

// Removes the element at the given index. The size of the list is
// decreased by one.
//
public void RemoveAt(int index)
{
ArgumentOutOfRangeException.ThrowIfGreaterThanOrEqual((uint)index, (uint)_size, nameof(index));
_size--;
if (index < _size)
{
Array.Copy(_items, index + 1, _items, index, _size - index);
}
_items[_size] = default!;
_version++;
}

// ToArray returns a new Object array containing the contents of the List.
// This requires copying the List, which is an O(n) operation.
public T[] ToArray()
{
T[] array = new T[_size];
Array.Copy(_items, 0, array, 0, _size);
return array;
}
#endif
}

#if !TYPE_LOADER_IMPLEMENTATION
// LowLevelList<T> with full IList<T> implementation
internal sealed class LowLevelListWithIList<T> : LowLevelList<T>, IList<T>
{
public LowLevelListWithIList()
{
}

public LowLevelListWithIList(int capacity)
: base(capacity)
{
}

public LowLevelListWithIList(IEnumerable<T> collection)
: base(collection)
{
}

// Is this List read-only?
bool ICollection<T>.IsReadOnly
{
get { return false; }
}

/// <internalonly/>
IEnumerator<T> IEnumerable<T>.GetEnumerator()
{
return new Enumerator(this);
}

System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator()
{
return new Enumerator(this);
}

private struct Enumerator : IEnumerator<T>, System.Collections.IEnumerator
{
private LowLevelListWithIList<T> _list;
private int _index;
private int _version;
private T? _current;

internal Enumerator(LowLevelListWithIList<T> list)
{
_list = list;
_index = 0;
_version = list._version;
_current = default(T);
}

public void Dispose()
{
}

public bool MoveNext()
{
LowLevelListWithIList<T> localList = _list;

if (_version == localList._version && ((uint)_index < (uint)localList._size))
{
_current = localList._items[_index];
_index++;
return true;
}
return MoveNextRare();
}

private bool MoveNextRare()
{
if (_version != _list._version)
{
throw new InvalidOperationException();
}

_index = _list._size + 1;
_current = default(T);
return false;
}

public T Current
{
get
{
return _current!;
}
}

object? System.Collections.IEnumerator.Current
{
get
{
if (_index == 0 || _index == _list._size + 1)
{
throw new InvalidOperationException();
}
return Current;
}
}

void System.Collections.IEnumerator.Reset()
{
if (_version != _list._version)
{
throw new InvalidOperationException();
}

_index = 0;
_current = default(T);
}
}
}
#endif // !TYPE_LOADER_IMPLEMENTATION
}
19 changes: 12 additions & 7 deletions src/coreclr/nativeaot/System.Private.CoreLib/src/System/Reflection/Attribute.NativeAot.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -135,18 +135,23 @@ private static Attribute OneOrNull(IEnumerable<CustomAttributeData> results)
Justification = "Arrays of reference types are safe to create.")]
private static Attribute[] Instantiate(IEnumerable<CustomAttributeData> cads, Type actualElementType)
{
LowLevelList<Attribute> attributes = new LowLevelList<Attribute>();
ArrayBuilder<Attribute> attributes = default;
foreach (CustomAttributeData cad in cads)
{
Attribute instantiatedAttribute = cad.Instantiate();
attributes.Add(instantiatedAttribute);
}
int count = attributes.Count;
Attribute[] result = actualElementType.ContainsGenericParameters
? new Attribute[count]
: (Attribute[])Array.CreateInstance(actualElementType, count);
attributes.CopyTo(result, 0);
return result;

if (actualElementType.ContainsGenericParameters)
{
return attributes.ToArray();
}
else
{
Attribute[] result = (Attribute[])Array.CreateInstance(actualElementType, attributes.Count);
attributes.CopyTo(result);
return result;
}
}
}
}
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