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//------------------------------------------------------------------------------
// <copyright file="InternalConfigRoot.cs" company="Microsoft">
// Copyright (c) Microsoft Corporation. All rights reserved.
// </copyright>
//------------------------------------------------------------------------------
namespace System.Configuration.Internal {
using System.Configuration.Internal;
using System.Collections;
using System.Collections.Specialized;
using System.Configuration;
using System.Globalization;
using System.IO;
using System.Runtime.InteropServices;
using System.Security.Permissions;
using System.Security;
using System.Text;
using System.Xml;
using System.Threading;
//
// InternalConfigRoot holds the root of a configuration hierarchy.
// It managed creation, removal, and the search for BaseConfigurationRecord's.
// in a thread-safe manner.
//
// The BaseConfigurationRecord hierarchy is protected with the
// _hierarchyLock. Functions that assume that the lock as been
// taken begin with the prefix "hl", for example, "hlFindConfigRecord".
//
internal sealed class InternalConfigRoot : IInternalConfigRoot {
IInternalConfigHost _host; // host, need to create records
IInternalConfigurationBuilderHost _configBuilderHost; // _configBuilderHost, need to create records
ReaderWriterLock _hierarchyLock; // lock to protect hierarchy
BaseConfigurationRecord _rootConfigRecord; // root config record, one level above machine.config.
bool _isDesignTime; // Is the hierarchy for runtime or designtime?
private Configuration _CurrentConfiguration = null;
public event InternalConfigEventHandler ConfigChanged;
public event InternalConfigEventHandler ConfigRemoved;
internal InternalConfigRoot() { }
internal InternalConfigRoot(Configuration currentConfiguration) {
_CurrentConfiguration = currentConfiguration;
}
void IInternalConfigRoot.Init(IInternalConfigHost host, bool isDesignTime) {
_host = host;
_configBuilderHost = host as IInternalConfigurationBuilderHost;
_isDesignTime = isDesignTime;
_hierarchyLock = new ReaderWriterLock();
// Dummy record to hold _children for root
if (_isDesignTime) {
_rootConfigRecord = MgmtConfigurationRecord.Create(this, null, string.Empty, null);
}
else {
_rootConfigRecord = (BaseConfigurationRecord) RuntimeConfigurationRecord.Create(this, null, string.Empty);
}
}
internal IInternalConfigHost Host {
get {return _host;}
}
internal IInternalConfigurationBuilderHost ConfigBuilderHost {
get { return _configBuilderHost; }
}
internal BaseConfigurationRecord RootConfigRecord {
get {return _rootConfigRecord;}
}
bool IInternalConfigRoot.IsDesignTime {
get {return _isDesignTime;}
}
private void AcquireHierarchyLockForRead() {
// Protect against unexpected recursive entry on this thread.
// We do this in retail, too, because the results would be very bad if this were to fail,
// and the testing for this is not easy for all scenarios.
Debug.Assert(!_hierarchyLock.IsReaderLockHeld, "!_hierarchyLock.IsReaderLockHeld");
if (_hierarchyLock.IsReaderLockHeld) {
throw ExceptionUtil.UnexpectedError("System.Configuration.Internal.InternalConfigRoot::AcquireHierarchyLockForRead - reader lock already held by this thread");
}
Debug.Assert(!_hierarchyLock.IsWriterLockHeld, "!_hierarchyLock.IsWriterLockHeld");
if (_hierarchyLock.IsWriterLockHeld) {
throw ExceptionUtil.UnexpectedError("System.Configuration.Internal.InternalConfigRoot::AcquireHierarchyLockForRead - writer lock already held by this thread");
}
_hierarchyLock.AcquireReaderLock(-1);
}
private void ReleaseHierarchyLockForRead() {
Debug.Assert(!_hierarchyLock.IsWriterLockHeld, "!_hierarchyLock.IsWriterLockHeld");
if (_hierarchyLock.IsReaderLockHeld) {
_hierarchyLock.ReleaseReaderLock();
}
}
private void AcquireHierarchyLockForWrite() {
// Protect against unexpected recursive entry on this thread.
// We do this in retail, too, because the results would be very bad if this were to fail,
// and the testing for this is not easy for all scenarios.
if (_hierarchyLock.IsReaderLockHeld) {
throw ExceptionUtil.UnexpectedError("System.Configuration.Internal.InternalConfigRoot::AcquireHierarchyLockForWrite - reader lock already held by this thread");
}
if (_hierarchyLock.IsWriterLockHeld) {
throw ExceptionUtil.UnexpectedError("System.Configuration.Internal.InternalConfigRoot::AcquireHierarchyLockForWrite - writer lock already held by this thread");
}
_hierarchyLock.AcquireWriterLock(-1);
}
private void ReleaseHierarchyLockForWrite() {
Debug.Assert(!_hierarchyLock.IsReaderLockHeld, "!_hierarchyLock.IsReaderLockHeld");
if (_hierarchyLock.IsWriterLockHeld) {
_hierarchyLock.ReleaseWriterLock();
}
}
//
// Find a config record.
// If found, nextIndex == parts.Length and the resulting record is in currentRecord.
// If not found, nextIndex is the index of the part of the path not found, and currentRecord
// is the record that has been found so far (nexIndex - 1).
//
private void hlFindConfigRecord(string[] parts, out int nextIndex, out BaseConfigurationRecord currentRecord) {
currentRecord = _rootConfigRecord;
nextIndex = 0;
for (; nextIndex < parts.Length; nextIndex++) {
BaseConfigurationRecord childRecord = currentRecord.hlGetChild(parts[nextIndex]);
if (childRecord == null)
break;
currentRecord = childRecord;
}
}
//
// Get a config section.
//
public object GetSection(string section, string configPath) {
BaseConfigurationRecord configRecord = (BaseConfigurationRecord) GetUniqueConfigRecord(configPath);
object result = configRecord.GetSection(section);
return result;
}
//
// Get the nearest ancestor path (including self) which contains unique configuration information.
//
public string GetUniqueConfigPath(string configPath) {
IInternalConfigRecord configRecord = GetUniqueConfigRecord(configPath);
if (configRecord == null) {
return null;
}
return configRecord.ConfigPath;
}
//
// Get the nearest ancestor record (including self) which contains unique configuration information.
//
public IInternalConfigRecord GetUniqueConfigRecord(string configPath) {
BaseConfigurationRecord configRecord = (BaseConfigurationRecord) GetConfigRecord(configPath);
while (configRecord.IsEmpty) {
BaseConfigurationRecord parentConfigRecord = configRecord.Parent;
// If all config records are empty, return the immediate child of the
// root placeholder (e.g. machine.config)
if (parentConfigRecord.IsRootConfig) {
break;
}
configRecord = parentConfigRecord;
}
return configRecord;
}
//
// Get the config record for a path.
// If the record does not exist, create it if it is needed.
//
public IInternalConfigRecord GetConfigRecord(string configPath) {
if (!ConfigPathUtility.IsValid(configPath)) {
throw ExceptionUtil.ParameterInvalid("configPath");
}
string[] parts = ConfigPathUtility.GetParts(configPath);
//
// First search under the reader lock, so that multiple searches
// can proceed in parallel.
//
try {
int index;
BaseConfigurationRecord currentRecord;
AcquireHierarchyLockForRead();
hlFindConfigRecord(parts, out index, out currentRecord);
// check if found
if (index == parts.Length || !currentRecord.hlNeedsChildFor(parts[index])) {
return currentRecord;
}
}
finally {
ReleaseHierarchyLockForRead();
}
//
// Not found, so search again under exclusive writer lock so that
// we can create the record.
//
try {
int index;
BaseConfigurationRecord currentRecord;
AcquireHierarchyLockForWrite();
hlFindConfigRecord(parts, out index, out currentRecord);
if (index == parts.Length) {
return currentRecord;
}
string currentConfigPath = String.Join(BaseConfigurationRecord.ConfigPathSeparatorString, parts, 0, index);
//
// create new records
//
while (index < parts.Length && currentRecord.hlNeedsChildFor(parts[index])) {
string configName = parts[index];
currentConfigPath = ConfigPathUtility.Combine(currentConfigPath, configName);
BaseConfigurationRecord childRecord;
Debug.Trace("ConfigurationCreate", "Creating config record for " + currentConfigPath);
if (_isDesignTime) {
childRecord = MgmtConfigurationRecord.Create(this, currentRecord, currentConfigPath, null);
}
else {
childRecord = (BaseConfigurationRecord) RuntimeConfigurationRecord.Create(this, currentRecord, currentConfigPath);
}
currentRecord.hlAddChild(configName, childRecord);
index++;
currentRecord = childRecord;
}
return currentRecord;
}
finally {
ReleaseHierarchyLockForWrite();
}
}
//
// Find and remove the config record and all its children for the config path.
// Optionally ensure the config record matches a desired config record.
//
void RemoveConfigImpl(string configPath, BaseConfigurationRecord configRecord) {
if (!ConfigPathUtility.IsValid(configPath)) {
throw ExceptionUtil.ParameterInvalid("configPath");
}
string[] parts = ConfigPathUtility.GetParts(configPath);
BaseConfigurationRecord currentRecord;
// search under exclusive writer lock
try {
int index;
AcquireHierarchyLockForWrite();
hlFindConfigRecord(parts, out index, out currentRecord);
// Return if not found, or does not match the one we are trying to remove.
if (index != parts.Length || (configRecord != null && !Object.ReferenceEquals(configRecord, currentRecord)))
return;
// Remove it from the hierarchy.
currentRecord.Parent.hlRemoveChild(parts[parts.Length - 1]);
}
finally {
ReleaseHierarchyLockForWrite();
}
OnConfigRemoved(new InternalConfigEventArgs(configPath));
// Close the record. This is safe to do outside the lock.
currentRecord.CloseRecursive();
}
//
// Find and remove the config record and all its children for the config path.
//
public void RemoveConfig(string configPath) {
RemoveConfigImpl(configPath, null);
}
//
// Remove the config record and all its children for the config path.
//
public void RemoveConfigRecord(BaseConfigurationRecord configRecord) {
RemoveConfigImpl(configRecord.ConfigPath, configRecord);
}
//
// Clear the result of a configSection evaluation at a particular point
// in the hierarchy.
//
public void ClearResult(BaseConfigurationRecord configRecord, string configKey, bool forceEvaluation) {
string[] parts = ConfigPathUtility.GetParts(configRecord.ConfigPath);
try {
int index;
BaseConfigurationRecord currentRecord;
AcquireHierarchyLockForWrite();
hlFindConfigRecord(parts, out index, out currentRecord);
// clear result only if configRecord it is still in the hierarchy
if (index == parts.Length && Object.ReferenceEquals(configRecord, currentRecord)) {
currentRecord.hlClearResultRecursive(configKey, forceEvaluation);
}
}
finally {
ReleaseHierarchyLockForWrite();
}
}
// Fire the ConfigRemoved event.
private void OnConfigRemoved(InternalConfigEventArgs e) {
InternalConfigEventHandler handler = ConfigRemoved;
if (handler != null) {
handler(this, e);
}
}
// Fire the ConfigChanged event for a configPath.
internal void FireConfigChanged(string configPath) {
OnConfigChanged(new InternalConfigEventArgs(configPath));
}
// Fire the ConfigChanged event.
private void OnConfigChanged(InternalConfigEventArgs e) {
InternalConfigEventHandler handler = ConfigChanged;
if (handler != null) {
handler(this, e);
}
}
internal Configuration CurrentConfiguration {
get {
return _CurrentConfiguration;
}
}
}
}
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