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using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using System.Security;
using System.Security.Permissions;
using System.Runtime.CompilerServices;
namespace System.Data.Linq {
using System.Data.Linq.Mapping;
using System.Data.Linq.Provider;
internal abstract class IdentityManager {
internal abstract object InsertLookup(MetaType type, object instance);
internal abstract bool RemoveLike(MetaType type, object instance);
internal abstract object Find(MetaType type, object[] keyValues);
internal abstract object FindLike(MetaType type, object instance);
internal static IdentityManager CreateIdentityManager(bool asReadOnly) {
if (asReadOnly) {
return new ReadOnlyIdentityManager();
}
else {
return new StandardIdentityManager();
}
}
class StandardIdentityManager : IdentityManager {
Dictionary<MetaType, IdentityCache> caches;
IdentityCache currentCache;
MetaType currentType;
internal StandardIdentityManager() {
this.caches = new Dictionary<MetaType, IdentityCache>();
}
internal override object InsertLookup(MetaType type, object instance) {
this.SetCurrent(type);
return this.currentCache.InsertLookup(instance);
}
internal override bool RemoveLike(MetaType type, object instance) {
this.SetCurrent(type);
return this.currentCache.RemoveLike(instance);
}
internal override object Find(MetaType type, object[] keyValues) {
this.SetCurrent(type);
return this.currentCache.Find(keyValues);
}
internal override object FindLike(MetaType type, object instance) {
this.SetCurrent(type);
return this.currentCache.FindLike(instance);
}
[MethodImpl(MethodImplOptions.NoInlining | MethodImplOptions.NoOptimization)]
private void SetCurrent(MetaType type) {
type = type.InheritanceRoot;
if (this.currentType != type) {
if (!this.caches.TryGetValue(type, out this.currentCache)) {
KeyManager km = GetKeyManager(type);
this.currentCache = (IdentityCache)Activator.CreateInstance(
typeof(IdentityCache<,>).MakeGenericType(type.Type, km.KeyType),
BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic, null,
new object[] { km }, null
);
this.caches.Add(type, this.currentCache);
}
this.currentType = type;
}
}
[MethodImpl(MethodImplOptions.NoInlining | MethodImplOptions.NoOptimization)]
static KeyManager GetKeyManager(MetaType type) {
int n = type.IdentityMembers.Count;
MetaDataMember mm = type.IdentityMembers[0];
KeyManager km = (KeyManager)Activator.CreateInstance(
typeof(SingleKeyManager<,>).MakeGenericType(type.Type, mm.Type),
BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic, null,
new object[] { mm.StorageAccessor, 0 }, null
);
for (int i = 1; i < n; i++) {
mm = type.IdentityMembers[i];
km = (KeyManager)
Activator.CreateInstance(
typeof(MultiKeyManager<,,>).MakeGenericType(type.Type, mm.Type, km.KeyType),
BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic, null,
new object[] { mm.StorageAccessor, i, km }, null
);
}
return km;
}
#region Nested type definitions
// These types are internal rather than private to work around
// CLR bug #117419 related to type visibility under partial trust
// in nested class scenarios.
internal abstract class KeyManager {
internal abstract Type KeyType { get; }
}
internal abstract class KeyManager<T, K> : KeyManager {
internal abstract K CreateKeyFromInstance(T instance);
internal abstract bool TryCreateKeyFromValues(object[] values, out K k);
internal abstract IEqualityComparer<K> Comparer { get; }
}
internal class SingleKeyManager<T, V> : KeyManager<T, V> {
bool isKeyNullAssignable;
MetaAccessor<T, V> accessor;
int offset;
IEqualityComparer<V> comparer;
internal SingleKeyManager(MetaAccessor<T, V> accessor, int offset) {
this.accessor = accessor;
this.offset = offset;
this.isKeyNullAssignable = System.Data.Linq.SqlClient.TypeSystem.IsNullAssignable(typeof(V));
}
internal override V CreateKeyFromInstance(T instance) {
return this.accessor.GetValue(instance);
}
internal override bool TryCreateKeyFromValues(object[] values, out V v) {
object o = values[this.offset];
if (o == null && !this.isKeyNullAssignable) {
v = default(V);
return false;
}
v = (V)o;
return true;
}
internal override Type KeyType {
get { return typeof(V); }
}
internal override IEqualityComparer<V> Comparer {
get {
if (this.comparer == null) {
this.comparer = EqualityComparer<V>.Default;
}
return this.comparer;
}
}
}
internal class MultiKeyManager<T, V1, V2> : KeyManager<T, MultiKey<V1, V2>> {
MetaAccessor<T, V1> accessor;
int offset;
KeyManager<T, V2> next;
IEqualityComparer<MultiKey<V1, V2>> comparer;
internal MultiKeyManager(MetaAccessor<T, V1> accessor, int offset, KeyManager<T, V2> next) {
this.accessor = accessor;
this.next = next;
this.offset = offset;
}
internal override MultiKey<V1, V2> CreateKeyFromInstance(T instance) {
return new MultiKey<V1, V2>(
this.accessor.GetValue(instance),
this.next.CreateKeyFromInstance(instance)
);
}
internal override bool TryCreateKeyFromValues(object[] values, out MultiKey<V1, V2> k) {
System.Diagnostics.Debug.Assert(this.offset < values.Length, "offset is outside the bounds of the values array");
object o = values[this.offset];
if (o == null && typeof(V1).IsValueType) {
k = default(MultiKey<V1, V2>);
return false;
}
V2 v2;
if (!this.next.TryCreateKeyFromValues(values, out v2)) {
k = default(MultiKey<V1, V2>);
return false;
}
k = new MultiKey<V1, V2>((V1)o, v2);
return true;
}
internal override Type KeyType {
get { return typeof(MultiKey<V1, V2>); }
}
internal override IEqualityComparer<MultiKey<V1, V2>> Comparer {
get {
if (this.comparer == null) {
this.comparer = new MultiKey<V1, V2>.Comparer(EqualityComparer<V1>.Default, next.Comparer);
}
return this.comparer;
}
}
}
internal struct MultiKey<T1, T2> {
T1 value1;
T2 value2;
internal MultiKey(T1 value1, T2 value2) {
this.value1 = value1;
this.value2 = value2;
}
internal class Comparer : IEqualityComparer<MultiKey<T1, T2>>, IEqualityComparer {
IEqualityComparer<T1> comparer1;
IEqualityComparer<T2> comparer2;
internal Comparer(IEqualityComparer<T1> comparer1, IEqualityComparer<T2> comparer2) {
this.comparer1 = comparer1;
this.comparer2 = comparer2;
}
public bool Equals(MultiKey<T1, T2> x, MultiKey<T1, T2> y) {
return this.comparer1.Equals(x.value1, y.value1) &&
this.comparer2.Equals(x.value2, y.value2);
}
public int GetHashCode(MultiKey<T1, T2> x) {
return this.comparer1.GetHashCode(x.value1) ^ this.comparer2.GetHashCode(x.value2);
}
bool IEqualityComparer.Equals(object x, object y) {
return this.Equals((MultiKey<T1, T2>)x, (MultiKey<T1, T2>)y);
}
int IEqualityComparer.GetHashCode(object x) {
return this.GetHashCode((MultiKey<T1, T2>)x);
}
}
}
internal abstract class IdentityCache {
internal abstract object Find(object[] keyValues);
internal abstract object FindLike(object instance);
internal abstract object InsertLookup(object instance);
internal abstract bool RemoveLike(object instance);
}
internal class IdentityCache<T, K> : IdentityCache {
int[] buckets;
Slot[] slots;
int count;
int freeList;
KeyManager<T, K> keyManager;
IEqualityComparer<K> comparer;
public IdentityCache(KeyManager<T, K> keyManager) {
this.keyManager = keyManager;
this.comparer = keyManager.Comparer;
buckets = new int[7];
slots = new Slot[7];
freeList = -1;
}
internal override object InsertLookup(object instance) {
T value = (T)instance;
K key = this.keyManager.CreateKeyFromInstance(value);
Find(key, ref value, true);
return value;
}
internal override bool RemoveLike(object instance) {
T value = (T)instance;
K key = this.keyManager.CreateKeyFromInstance(value);
int hashCode = comparer.GetHashCode(key) & 0x7FFFFFFF;
int bucket = hashCode % buckets.Length;
int last = -1;
for (int i = buckets[bucket] - 1; i >= 0; last = i, i = slots[i].next) {
if (slots[i].hashCode == hashCode && comparer.Equals(slots[i].key, key)) {
if (last < 0) {
buckets[bucket] = slots[i].next + 1;
}
else {
slots[last].next = slots[i].next;
}
slots[i].hashCode = -1;
slots[i].value = default(T);
slots[i].next = freeList;
freeList = i;
return true;
}
}
return false;
}
internal override object Find(object[] keyValues) {
K key;
if (this.keyManager.TryCreateKeyFromValues(keyValues, out key)) {
T value = default(T);
if (Find(key, ref value, false))
return value;
}
return null;
}
internal override object FindLike(object instance) {
T value = (T)instance;
K key = this.keyManager.CreateKeyFromInstance(value);
if (Find(key, ref value, false))
return value;
return null;
}
bool Find(K key, ref T value, bool add) {
int hashCode = comparer.GetHashCode(key) & 0x7FFFFFFF;
for (int i = buckets[hashCode % buckets.Length] - 1; i >= 0; i = slots[i].next) {
if (slots[i].hashCode == hashCode && comparer.Equals(slots[i].key, key)) {
value = slots[i].value;
return true;
}
}
if (add) {
int index;
if (freeList >= 0) {
index = freeList;
freeList = slots[index].next;
}
else {
if (count == slots.Length) Resize();
index = count;
count++;
}
int bucket = hashCode % buckets.Length;
slots[index].hashCode = hashCode;
slots[index].key = key;
slots[index].value = value;
slots[index].next = buckets[bucket] - 1;
buckets[bucket] = index + 1;
}
return false;
}
void Resize() {
int newSize = checked(count * 2 + 1);
int[] newBuckets = new int[newSize];
Slot[] newSlots = new Slot[newSize];
Array.Copy(slots, 0, newSlots, 0, count);
for (int i = 0; i < count; i++) {
int bucket = newSlots[i].hashCode % newSize;
newSlots[i].next = newBuckets[bucket] - 1;
newBuckets[bucket] = i + 1;
}
buckets = newBuckets;
slots = newSlots;
}
internal struct Slot {
internal int hashCode;
internal K key;
internal T value;
internal int next;
}
}
#endregion
}
/// <summary>
/// This is the noop implementation used when object tracking is disabled.
/// </summary>
class ReadOnlyIdentityManager : IdentityManager {
internal ReadOnlyIdentityManager() { }
internal override object InsertLookup(MetaType type, object instance) { return instance; }
internal override bool RemoveLike(MetaType type, object instance) { return false; }
internal override object Find(MetaType type, object[] keyValues) { return null; }
internal override object FindLike(MetaType type, object instance) { return null; }
}
}
}
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