InternalConfigRoot.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / Configuration / System / Configuration / Internal / InternalConfigRoot.cs / 1305376 / InternalConfigRoot.cs
                        

                        
                            //------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
//----------------------------------------------------------------------------- 

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
        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;
            _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 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;
 
                AcquireHierarchyLockForRead(); 

                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 { 
                ReleaseHierarchyLockForRead();
            } 
        }

        // 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;
            } 
        }
    }
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.

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