Code:
/ 4.0 / 4.0 / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / Data / System / Data / ProviderBase / DbReferenceCollection.cs / 1305376 / DbReferenceCollection.cs
//------------------------------------------------------------------------------
//
// Copyright (c) Microsoft Corporation. All rights reserved.
//
// [....]
// [....]
//-----------------------------------------------------------------------------
namespace System.Data.ProviderBase {
using System;
using System.Collections;
using System.Diagnostics;
internal abstract class DbReferenceCollection {
#if ORACLE
abstract public void Add(object value, int tag);
abstract public void Notify(int message);
abstract public void Remove(object value);
#else
private struct CollectionEntry {
private int _tag; // information about the reference
private WeakReference _weak; // the reference itself.
public bool HasTarget {
get {
Debug.Assert((0 != _tag && null != _weak) || (null == _weak || !_weak.IsAlive), "0 tag with Target");
return ((0 != _tag) && null != _weak && _weak.IsAlive);
}
}
public bool InUse {
get {
return (null != _weak);
}
}
public int Tag {
get {
return _tag;
}
set {
_tag = value;
}
}
public object Target {
get {
if (0 != _tag) {
return _weak.Target;
}
Debug.Assert(!_weak.IsAlive, "0 tag with Target");
return null;
}
set {
if (null == _weak) {
_weak = new WeakReference(value, false);
}
else {
_weak.Target = value;
}
}
}
}
private CollectionEntry[] _items;
protected DbReferenceCollection() {
_items = new CollectionEntry[5];
}
abstract public void Add(object value, int tag);
protected void AddItem(object value, int tag) {
Debug.Assert(null != value && 0 != tag, "AddItem with null value or 0 tag");
CollectionEntry[] items = _items;
for (int i = 0; i < items.Length; ++i) {
if (!items[i].HasTarget) {
items[i].Target = value;
items[i].Tag = tag;
Debug.Assert(items[i].HasTarget, "missing expected target");
return;
}
}
int newlength = ((5 == items.Length) ? 15 : (items.Length + 15));
CollectionEntry[] jtems = new CollectionEntry[newlength];
for (int i = 0; i < items.Length; ++i) {
jtems[i] = items[i];
}
jtems[items.Length].Target = value;
jtems[items.Length].Tag = tag;
Debug.Assert(jtems[items.Length].HasTarget, "missing expected target");
_items = jtems;
}
internal IEnumerable Filter(int tag) {
return new DbFilteredReferenceCollection (_items, tag);
}
public void Notify(int message) {
CollectionEntry[] items = _items;
for (int index = 0; index < items.Length; ++index) {
if (items[index].InUse) {
object value = items[index].Target; // checks tag & gets target
if (null != value) {
Debug.Assert(items[index].HasTarget, "missing expected target");
if (!NotifyItem(message, items[index].Tag, value)) {
items[index].Tag = 0;
items[index].Target = null;
Debug.Assert(!items[index].HasTarget, "has unexpected target");
}
}
// else (0 == Tag) or !IsAlive
}
else {
Debug.Assert(!items[index].HasTarget, "has unexpected target");
break; // we're done as soon as we find the first null in the list
}
}
}
abstract protected bool NotifyItem(int message, int tag, object value);
public void Purge() {
CollectionEntry[] items = _items;
#if DEBUG
for(int i = 0; i < items.Length; ++i) {
Debug.Assert(!items[i].HasTarget, "unexpected target during purge");
}
#endif
if (100 < items.Length) {
_items = new CollectionEntry[5]; // revert back to 5 items if we're really big...
}
}
abstract public void Remove(object value);
protected void RemoveItem(object value) {
Debug.Assert(null != value, "RemoveItem with null");
CollectionEntry[] items = _items;
for (int index = 0; index < items.Length; ++index) {
if (items[index].InUse) {
if (value == items[index].Target) { // checks tag & gets target
items[index].Tag = 0;
items[index].Target = null;
Debug.Assert(!items[index].HasTarget, "has unexpected target");
break;
}
// else (0 == Tag) or !IsAlive or (value != Target)
}
else {
break; // we're done as soon as we find the first null in the list
}
}
}
private struct DbFilteredReferenceCollection : IEnumerable {
private readonly DbReferenceCollection.CollectionEntry[] _items;
private readonly int _filterTag;
internal DbFilteredReferenceCollection(DbReferenceCollection.CollectionEntry[] items, int filterTag) {
_items = items;
_filterTag = filterTag;
}
IEnumerator IEnumerable.GetEnumerator() {
return new DbFilteredReferenceCollectionedEnumerator(_items, _filterTag);
}
private struct DbFilteredReferenceCollectionedEnumerator : IEnumerator {
private readonly DbReferenceCollection.CollectionEntry[] _items;
private readonly int _filterTag;
private int _current;
internal DbFilteredReferenceCollectionedEnumerator(DbReferenceCollection.CollectionEntry[] items, int filterTag) {
_items = items;
_filterTag = filterTag;
_current = -1;
}
object IEnumerator.Current {
get {
return _items[_current].Target;
}
}
bool IEnumerator.MoveNext() {
while (++_current < _items.Length) {
if (_items[_current].InUse) {
if (_items[_current].Tag == _filterTag) {
return true;
}
}
else {
break;
}
}
return false;
}
void IEnumerator.Reset() {
_current = -1;
}
}
}
#endif
}
}
// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
//------------------------------------------------------------------------------
//
// Copyright (c) Microsoft Corporation. All rights reserved.
//
// [....]
// [....]
//-----------------------------------------------------------------------------
namespace System.Data.ProviderBase {
using System;
using System.Collections;
using System.Diagnostics;
internal abstract class DbReferenceCollection {
#if ORACLE
abstract public void Add(object value, int tag);
abstract public void Notify(int message);
abstract public void Remove(object value);
#else
private struct CollectionEntry {
private int _tag; // information about the reference
private WeakReference _weak; // the reference itself.
public bool HasTarget {
get {
Debug.Assert((0 != _tag && null != _weak) || (null == _weak || !_weak.IsAlive), "0 tag with Target");
return ((0 != _tag) && null != _weak && _weak.IsAlive);
}
}
public bool InUse {
get {
return (null != _weak);
}
}
public int Tag {
get {
return _tag;
}
set {
_tag = value;
}
}
public object Target {
get {
if (0 != _tag) {
return _weak.Target;
}
Debug.Assert(!_weak.IsAlive, "0 tag with Target");
return null;
}
set {
if (null == _weak) {
_weak = new WeakReference(value, false);
}
else {
_weak.Target = value;
}
}
}
}
private CollectionEntry[] _items;
protected DbReferenceCollection() {
_items = new CollectionEntry[5];
}
abstract public void Add(object value, int tag);
protected void AddItem(object value, int tag) {
Debug.Assert(null != value && 0 != tag, "AddItem with null value or 0 tag");
CollectionEntry[] items = _items;
for (int i = 0; i < items.Length; ++i) {
if (!items[i].HasTarget) {
items[i].Target = value;
items[i].Tag = tag;
Debug.Assert(items[i].HasTarget, "missing expected target");
return;
}
}
int newlength = ((5 == items.Length) ? 15 : (items.Length + 15));
CollectionEntry[] jtems = new CollectionEntry[newlength];
for (int i = 0; i < items.Length; ++i) {
jtems[i] = items[i];
}
jtems[items.Length].Target = value;
jtems[items.Length].Tag = tag;
Debug.Assert(jtems[items.Length].HasTarget, "missing expected target");
_items = jtems;
}
internal IEnumerable Filter(int tag) {
return new DbFilteredReferenceCollection (_items, tag);
}
public void Notify(int message) {
CollectionEntry[] items = _items;
for (int index = 0; index < items.Length; ++index) {
if (items[index].InUse) {
object value = items[index].Target; // checks tag & gets target
if (null != value) {
Debug.Assert(items[index].HasTarget, "missing expected target");
if (!NotifyItem(message, items[index].Tag, value)) {
items[index].Tag = 0;
items[index].Target = null;
Debug.Assert(!items[index].HasTarget, "has unexpected target");
}
}
// else (0 == Tag) or !IsAlive
}
else {
Debug.Assert(!items[index].HasTarget, "has unexpected target");
break; // we're done as soon as we find the first null in the list
}
}
}
abstract protected bool NotifyItem(int message, int tag, object value);
public void Purge() {
CollectionEntry[] items = _items;
#if DEBUG
for(int i = 0; i < items.Length; ++i) {
Debug.Assert(!items[i].HasTarget, "unexpected target during purge");
}
#endif
if (100 < items.Length) {
_items = new CollectionEntry[5]; // revert back to 5 items if we're really big...
}
}
abstract public void Remove(object value);
protected void RemoveItem(object value) {
Debug.Assert(null != value, "RemoveItem with null");
CollectionEntry[] items = _items;
for (int index = 0; index < items.Length; ++index) {
if (items[index].InUse) {
if (value == items[index].Target) { // checks tag & gets target
items[index].Tag = 0;
items[index].Target = null;
Debug.Assert(!items[index].HasTarget, "has unexpected target");
break;
}
// else (0 == Tag) or !IsAlive or (value != Target)
}
else {
break; // we're done as soon as we find the first null in the list
}
}
}
private struct DbFilteredReferenceCollection : IEnumerable {
private readonly DbReferenceCollection.CollectionEntry[] _items;
private readonly int _filterTag;
internal DbFilteredReferenceCollection(DbReferenceCollection.CollectionEntry[] items, int filterTag) {
_items = items;
_filterTag = filterTag;
}
IEnumerator IEnumerable.GetEnumerator() {
return new DbFilteredReferenceCollectionedEnumerator(_items, _filterTag);
}
private struct DbFilteredReferenceCollectionedEnumerator : IEnumerator {
private readonly DbReferenceCollection.CollectionEntry[] _items;
private readonly int _filterTag;
private int _current;
internal DbFilteredReferenceCollectionedEnumerator(DbReferenceCollection.CollectionEntry[] items, int filterTag) {
_items = items;
_filterTag = filterTag;
_current = -1;
}
object IEnumerator.Current {
get {
return _items[_current].Target;
}
}
bool IEnumerator.MoveNext() {
while (++_current < _items.Length) {
if (_items[_current].InUse) {
if (_items[_current].Tag == _filterTag) {
return true;
}
}
else {
break;
}
}
return false;
}
void IEnumerator.Reset() {
_current = -1;
}
}
}
#endif
}
}
// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
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