Code:
/ Dotnetfx_Vista_SP2 / Dotnetfx_Vista_SP2 / 8.0.50727.4016 / DEVDIV / depot / DevDiv / releases / whidbey / NetFxQFE / ndp / fx / src / Data / System / Data / ProviderBase / DbConnectionPoolGroup.cs / 1 / DbConnectionPoolGroup.cs
//------------------------------------------------------------------------------
//
// Copyright (c) Microsoft Corporation. All rights reserved.
//
// [....]
//-----------------------------------------------------------------------------
namespace System.Data.ProviderBase {
using System;
using System.Collections;
using System.Collections.Specialized;
using System.Data.Common;
#if ORACLE
using System.Data.OracleClient;
#endif
using System.Diagnostics;
using System.Threading;
// set_ConnectionString calls DbConnectionFactory.GetConnectionPoolGroup
// when not found a new pool entry is created and potentially added
// DbConnectionPoolGroup starts in the Active state
// Open calls DbConnectionFactory.GetConnectionPool
// if the existing pool entry is Disabled, GetConnectionPoolGroup is called for a new entry
// DbConnectionFactory.GetConnectionPool calls DbConnectionPoolGroup.GetConnectionPool
// DbConnectionPoolGroup.GetConnectionPool will return pool for the current identity
// or null if identity is restricted or pooling is disabled or state is disabled at time of add
// state changes are Active->Active, Idle->Active
// DbConnectionFactory.PruneConnectionPoolGroups calls Prune
// which will QueuePoolForRelease on all empty pools
// and once no pools remain, change state from Active->Idle->Disabled
// Once Disabled, factory can remove its reference to the pool entry
sealed internal class DbConnectionPoolGroup {
private readonly DbConnectionOptions _connectionOptions;
private readonly DbConnectionPoolGroupOptions _poolGroupOptions;
private HybridDictionary _poolCollection;
private int _poolCount; // number of pools
private int _state; // see PoolGroupState* below
private DbConnectionPoolGroupProviderInfo _providerInfo;
private DbMetaDataFactory _metaDataFactory;
private static int _objectTypeCount; // Bid counter
internal readonly int _objectID = System.Threading.Interlocked.Increment(ref _objectTypeCount);
// always lock this before changing _state, we don't want to move out of `the disabled state
// PoolGroupStateUninitialized = 0;
private const int PoolGroupStateActive = 1; // initial state, GetPoolGroup from cache, connection Open
private const int PoolGroupStateIdle = 2; // all pools are pruned via Clear
private const int PoolGroupStateDisabled = 4; // factory pool entry prunning method
internal DbConnectionPoolGroup (DbConnectionOptions connectionOptions, DbConnectionPoolGroupOptions poolGroupOptions) {
Debug.Assert(null != connectionOptions, "null connection options");
Debug.Assert(null == poolGroupOptions || ADP.IsWindowsNT, "should not have pooling options on Win9x");
_connectionOptions = connectionOptions;
_poolGroupOptions = poolGroupOptions;
// always lock this object before changing state
// HybridDictionary does not create any sub-objects until add
// so it is safe to use for non-pooled connection as long as
// we check _poolGroupOptions first
_poolCollection = new HybridDictionary(1, false);
_state = PoolGroupStateActive; // VSWhidbey 112102
}
internal DbConnectionOptions ConnectionOptions {
get {
return _connectionOptions;
}
}
internal int Count {
get {
// NOTE: the use of this property does not indicate activity,
// on the pool entry because it only it is only used to identify
// empty pool entries when we're pruning them.
return _poolCount;
}
}
internal DbConnectionPoolGroupProviderInfo ProviderInfo {
get {
return _providerInfo;
}
set {
_providerInfo = value;
if(null!=value) {
_providerInfo.PoolGroup = this;
}
}
}
internal bool IsDisabled {
get {
return (PoolGroupStateDisabled == _state);
}
}
internal int ObjectID {
get {
return _objectID;
}
}
internal DbConnectionPoolGroupOptions PoolGroupOptions {
get {
return _poolGroupOptions;
}
}
internal DbMetaDataFactory MetaDataFactory{
get {
return _metaDataFactory;
}
set {
_metaDataFactory = value;
}
}
internal void Clear() {
ClearInternal(true);
}
private bool ClearInternal(bool clearing) {
// must be multi-thread safe with competing calls by Clear and Prune via background thread
// will return true for Prune on if the pool entry is Disabled or not
lock (this) {
HybridDictionary poolCollection = _poolCollection;
if (0 < poolCollection.Count) {
HybridDictionary newPoolCollection = new HybridDictionary(poolCollection.Count, false);
foreach (DictionaryEntry entry in poolCollection) {
if (null != entry.Value) {
DbConnectionPool pool = (DbConnectionPool)entry.Value;
//
// Actually prune the pool if the user requested it (clearing == true)
// or if there are no connections in the pool and no errors occurred.
// Empty pool during pruning indicates zero or low activity, but
// an error state indicates the pool needs to stay around to
// throttle new connection attempts.
if (clearing || (!pool.ErrorOccurred && 0 == pool.Count)) {
// Order is important here. First we remove the pool
// from the collection of pools so no one will try
// to use it while we're processing and finally we put the
// pool into a list of pools to be released when they
// are completely empty.
DbConnectionFactory connectionFactory = pool.ConnectionFactory;
connectionFactory.PerformanceCounters.NumberOfActiveConnectionPools.Decrement();
connectionFactory.QueuePoolForRelease(pool, clearing);
}
else {
newPoolCollection.Add(entry.Key, entry.Value);
}
}
}
_poolCollection = newPoolCollection;
_poolCount = newPoolCollection.Count;
}
// must be pruning thread to change state and no connections
// otherwise pruning thread risks making entry disabled soon after user calls ClearPool
if (!clearing && (0 == _poolCount)) {
if (PoolGroupStateActive == _state) {
_state = PoolGroupStateIdle;
Bid.Trace(" %d#, Idle\n", ObjectID);
}
else if (PoolGroupStateIdle == _state) {
_state = PoolGroupStateDisabled;
Bid.Trace(" %d#, Disabled\n", ObjectID);
}
}
return (PoolGroupStateDisabled == _state);
}
}
internal DbConnectionPool GetConnectionPool(DbConnectionFactory connectionFactory) {
// When this method returns null it indicates that the connection
// factory should not use pooling.
// We don't support connection pooling on Win9x; it lacks too
// many of the APIs we require.
// PoolGroupOptions will only be null when we're not supposed to pool
// connections.
object pool = null;
if (null != _poolGroupOptions) {
Debug.Assert(ADP.IsWindowsNT, "should not be pooling on Win9x");
DbConnectionPoolIdentity currentIdentity = DbConnectionPoolIdentity.NoIdentity;
if (_poolGroupOptions.PoolByIdentity) {
// if we're pooling by identity (because integrated security is
// being used for these connections) then we need to go out and
// search for the connectionPool that matches the current identity.
currentIdentity = DbConnectionPoolIdentity.GetCurrent();
// If the current token is restricted in some way, then we must
// not attempt to pool these connections.
if (currentIdentity.IsRestricted) {
currentIdentity = null;
}
}
if (null != currentIdentity) {
HybridDictionary poolCollection = _poolCollection;
pool = poolCollection[currentIdentity]; // find the pool
if (null == pool) {
DbConnectionPoolProviderInfo connectionPoolProviderInfo = connectionFactory.CreateConnectionPoolProviderInfo(this.ConnectionOptions);
// optimistically create pool, but its callbacks are delayed until after actual add
DbConnectionPool newPool = new DbConnectionPool(connectionFactory, this, currentIdentity, connectionPoolProviderInfo);
lock (this) {
// Did someone already add it to the list?
poolCollection = _poolCollection;
pool = poolCollection[currentIdentity]; // find the pool
if (null == pool) {
if (MarkPoolGroupAsActive()) {
// If we get here, we know for certain that we there isn't
// a pool that matches the current identity, so we have to
// add the optimistically created one
newPool.Startup(); // must start pool before usage
HybridDictionary newPoolCollection = new HybridDictionary(1+poolCollection.Count, false);
foreach(DictionaryEntry entry in poolCollection) {
newPoolCollection.Add(entry.Key, entry.Value);
}
newPoolCollection.Add(currentIdentity, newPool);
connectionFactory.PerformanceCounters.NumberOfActiveConnectionPools.Increment();
_poolCollection = newPoolCollection;
_poolCount = newPoolCollection.Count;
pool = newPool;
newPool = null;
}
else {
// else pool entry has been disabled so don't create new pools
Debug.Assert(PoolGroupStateDisabled == _state, "state should be disabled");
}
}
else {
// else found an existing pool to use instead
Debug.Assert(PoolGroupStateActive == _state, "state should be active since a pool exists and lock holds");
}
}
if (null != newPool) {
// don't need to call connectionFactory.QueuePoolForRelease(newPool) because
// pool callbacks were delayed and no risk of connections being created
newPool.Shutdown();
}
}
// the found pool could be in any state
}
}
if (null == pool) {
lock(this) {
// keep the pool entry state active when not pooling
MarkPoolGroupAsActive();
}
}
return (DbConnectionPool)pool;
}
private bool MarkPoolGroupAsActive() {
// when getting a connection, make the entry active if it was idle (but not disabled)
// must always lock this before calling
if (PoolGroupStateIdle == _state) {
_state = PoolGroupStateActive;
Bid.Trace(" %d#, Active\n", ObjectID);
}
return (PoolGroupStateActive == _state);
}
internal bool Prune() {
// must only call from DbConnectionFactory.PruneConnectionPoolGroups on background timer thread
// must lock(DbConnectionFactory._connectionPoolGroups.SyncRoot) before calling ReadyToRemove
// to avoid conflict with DbConnectionFactory.CreateConnectionPoolGroup replacing pool entry
return ClearInternal(false);
}
}
}
// 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.Collections.Specialized;
using System.Data.Common;
#if ORACLE
using System.Data.OracleClient;
#endif
using System.Diagnostics;
using System.Threading;
// set_ConnectionString calls DbConnectionFactory.GetConnectionPoolGroup
// when not found a new pool entry is created and potentially added
// DbConnectionPoolGroup starts in the Active state
// Open calls DbConnectionFactory.GetConnectionPool
// if the existing pool entry is Disabled, GetConnectionPoolGroup is called for a new entry
// DbConnectionFactory.GetConnectionPool calls DbConnectionPoolGroup.GetConnectionPool
// DbConnectionPoolGroup.GetConnectionPool will return pool for the current identity
// or null if identity is restricted or pooling is disabled or state is disabled at time of add
// state changes are Active->Active, Idle->Active
// DbConnectionFactory.PruneConnectionPoolGroups calls Prune
// which will QueuePoolForRelease on all empty pools
// and once no pools remain, change state from Active->Idle->Disabled
// Once Disabled, factory can remove its reference to the pool entry
sealed internal class DbConnectionPoolGroup {
private readonly DbConnectionOptions _connectionOptions;
private readonly DbConnectionPoolGroupOptions _poolGroupOptions;
private HybridDictionary _poolCollection;
private int _poolCount; // number of pools
private int _state; // see PoolGroupState* below
private DbConnectionPoolGroupProviderInfo _providerInfo;
private DbMetaDataFactory _metaDataFactory;
private static int _objectTypeCount; // Bid counter
internal readonly int _objectID = System.Threading.Interlocked.Increment(ref _objectTypeCount);
// always lock this before changing _state, we don't want to move out of `the disabled state
// PoolGroupStateUninitialized = 0;
private const int PoolGroupStateActive = 1; // initial state, GetPoolGroup from cache, connection Open
private const int PoolGroupStateIdle = 2; // all pools are pruned via Clear
private const int PoolGroupStateDisabled = 4; // factory pool entry prunning method
internal DbConnectionPoolGroup (DbConnectionOptions connectionOptions, DbConnectionPoolGroupOptions poolGroupOptions) {
Debug.Assert(null != connectionOptions, "null connection options");
Debug.Assert(null == poolGroupOptions || ADP.IsWindowsNT, "should not have pooling options on Win9x");
_connectionOptions = connectionOptions;
_poolGroupOptions = poolGroupOptions;
// always lock this object before changing state
// HybridDictionary does not create any sub-objects until add
// so it is safe to use for non-pooled connection as long as
// we check _poolGroupOptions first
_poolCollection = new HybridDictionary(1, false);
_state = PoolGroupStateActive; // VSWhidbey 112102
}
internal DbConnectionOptions ConnectionOptions {
get {
return _connectionOptions;
}
}
internal int Count {
get {
// NOTE: the use of this property does not indicate activity,
// on the pool entry because it only it is only used to identify
// empty pool entries when we're pruning them.
return _poolCount;
}
}
internal DbConnectionPoolGroupProviderInfo ProviderInfo {
get {
return _providerInfo;
}
set {
_providerInfo = value;
if(null!=value) {
_providerInfo.PoolGroup = this;
}
}
}
internal bool IsDisabled {
get {
return (PoolGroupStateDisabled == _state);
}
}
internal int ObjectID {
get {
return _objectID;
}
}
internal DbConnectionPoolGroupOptions PoolGroupOptions {
get {
return _poolGroupOptions;
}
}
internal DbMetaDataFactory MetaDataFactory{
get {
return _metaDataFactory;
}
set {
_metaDataFactory = value;
}
}
internal void Clear() {
ClearInternal(true);
}
private bool ClearInternal(bool clearing) {
// must be multi-thread safe with competing calls by Clear and Prune via background thread
// will return true for Prune on if the pool entry is Disabled or not
lock (this) {
HybridDictionary poolCollection = _poolCollection;
if (0 < poolCollection.Count) {
HybridDictionary newPoolCollection = new HybridDictionary(poolCollection.Count, false);
foreach (DictionaryEntry entry in poolCollection) {
if (null != entry.Value) {
DbConnectionPool pool = (DbConnectionPool)entry.Value;
//
// Actually prune the pool if the user requested it (clearing == true)
// or if there are no connections in the pool and no errors occurred.
// Empty pool during pruning indicates zero or low activity, but
// an error state indicates the pool needs to stay around to
// throttle new connection attempts.
if (clearing || (!pool.ErrorOccurred && 0 == pool.Count)) {
// Order is important here. First we remove the pool
// from the collection of pools so no one will try
// to use it while we're processing and finally we put the
// pool into a list of pools to be released when they
// are completely empty.
DbConnectionFactory connectionFactory = pool.ConnectionFactory;
connectionFactory.PerformanceCounters.NumberOfActiveConnectionPools.Decrement();
connectionFactory.QueuePoolForRelease(pool, clearing);
}
else {
newPoolCollection.Add(entry.Key, entry.Value);
}
}
}
_poolCollection = newPoolCollection;
_poolCount = newPoolCollection.Count;
}
// must be pruning thread to change state and no connections
// otherwise pruning thread risks making entry disabled soon after user calls ClearPool
if (!clearing && (0 == _poolCount)) {
if (PoolGroupStateActive == _state) {
_state = PoolGroupStateIdle;
Bid.Trace(" %d#, Idle\n", ObjectID);
}
else if (PoolGroupStateIdle == _state) {
_state = PoolGroupStateDisabled;
Bid.Trace(" %d#, Disabled\n", ObjectID);
}
}
return (PoolGroupStateDisabled == _state);
}
}
internal DbConnectionPool GetConnectionPool(DbConnectionFactory connectionFactory) {
// When this method returns null it indicates that the connection
// factory should not use pooling.
// We don't support connection pooling on Win9x; it lacks too
// many of the APIs we require.
// PoolGroupOptions will only be null when we're not supposed to pool
// connections.
object pool = null;
if (null != _poolGroupOptions) {
Debug.Assert(ADP.IsWindowsNT, "should not be pooling on Win9x");
DbConnectionPoolIdentity currentIdentity = DbConnectionPoolIdentity.NoIdentity;
if (_poolGroupOptions.PoolByIdentity) {
// if we're pooling by identity (because integrated security is
// being used for these connections) then we need to go out and
// search for the connectionPool that matches the current identity.
currentIdentity = DbConnectionPoolIdentity.GetCurrent();
// If the current token is restricted in some way, then we must
// not attempt to pool these connections.
if (currentIdentity.IsRestricted) {
currentIdentity = null;
}
}
if (null != currentIdentity) {
HybridDictionary poolCollection = _poolCollection;
pool = poolCollection[currentIdentity]; // find the pool
if (null == pool) {
DbConnectionPoolProviderInfo connectionPoolProviderInfo = connectionFactory.CreateConnectionPoolProviderInfo(this.ConnectionOptions);
// optimistically create pool, but its callbacks are delayed until after actual add
DbConnectionPool newPool = new DbConnectionPool(connectionFactory, this, currentIdentity, connectionPoolProviderInfo);
lock (this) {
// Did someone already add it to the list?
poolCollection = _poolCollection;
pool = poolCollection[currentIdentity]; // find the pool
if (null == pool) {
if (MarkPoolGroupAsActive()) {
// If we get here, we know for certain that we there isn't
// a pool that matches the current identity, so we have to
// add the optimistically created one
newPool.Startup(); // must start pool before usage
HybridDictionary newPoolCollection = new HybridDictionary(1+poolCollection.Count, false);
foreach(DictionaryEntry entry in poolCollection) {
newPoolCollection.Add(entry.Key, entry.Value);
}
newPoolCollection.Add(currentIdentity, newPool);
connectionFactory.PerformanceCounters.NumberOfActiveConnectionPools.Increment();
_poolCollection = newPoolCollection;
_poolCount = newPoolCollection.Count;
pool = newPool;
newPool = null;
}
else {
// else pool entry has been disabled so don't create new pools
Debug.Assert(PoolGroupStateDisabled == _state, "state should be disabled");
}
}
else {
// else found an existing pool to use instead
Debug.Assert(PoolGroupStateActive == _state, "state should be active since a pool exists and lock holds");
}
}
if (null != newPool) {
// don't need to call connectionFactory.QueuePoolForRelease(newPool) because
// pool callbacks were delayed and no risk of connections being created
newPool.Shutdown();
}
}
// the found pool could be in any state
}
}
if (null == pool) {
lock(this) {
// keep the pool entry state active when not pooling
MarkPoolGroupAsActive();
}
}
return (DbConnectionPool)pool;
}
private bool MarkPoolGroupAsActive() {
// when getting a connection, make the entry active if it was idle (but not disabled)
// must always lock this before calling
if (PoolGroupStateIdle == _state) {
_state = PoolGroupStateActive;
Bid.Trace(" %d#, Active\n", ObjectID);
}
return (PoolGroupStateActive == _state);
}
internal bool Prune() {
// must only call from DbConnectionFactory.PruneConnectionPoolGroups on background timer thread
// must lock(DbConnectionFactory._connectionPoolGroups.SyncRoot) before calling ReadyToRemove
// to avoid conflict with DbConnectionFactory.CreateConnectionPoolGroup replacing pool entry
return ClearInternal(false);
}
}
}
// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
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