//------------------------------------------------------------------------------
// <copyright file="XmlSchemaCollection.cs" company="Microsoft">
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// </copyright> 
// <owner current="true" primary="true">Microsoft</owner>                                                               
//------------------------------------------------------------------------------

namespace System.Xml.Schema {

    using System;
    using System.Threading;
    using System.Collections;
    using System.Xml.Schema;
    using System.Runtime.Versioning;


    /// <include file='doc\XmlSchemaCollection.uex' path='docs/doc[@for="XmlSchemaCollection"]/*' />
    /// <devdoc>
    ///    <para>The XmlSchemaCollection contains a set of namespace URI's.
    ///       Each namespace also have an associated private data cache
    ///       corresponding to the XML-Data Schema or W3C XML Schema.
    ///       The XmlSchemaCollection will able to load XSD and XDR schemas,
    ///       and compile them into an internal "cooked schema representation".
    ///       The Validate method then uses this internal representation for
    ///       efficient runtime validation of any given subtree.</para>
    /// </devdoc>
    [Obsolete("Use System.Xml.Schema.XmlSchemaSet for schema compilation and validation. https://go.microsoft.com/fwlink/?linkid=14202")]
    public sealed class XmlSchemaCollection: ICollection {
        private Hashtable               collection;
        private XmlNameTable            nameTable;
        private SchemaNames             schemaNames;
        private ReaderWriterLock        wLock;
        private int                     timeout = Timeout.Infinite;
        private bool                    isThreadSafe = true;
        private ValidationEventHandler  validationEventHandler = null;
        private XmlResolver             xmlResolver = null;


        /// <include file='doc\XmlSchemaCollection.uex' path='docs/doc[@for="XmlSchemaCollection.XmlSchemaCollection"]/*' />
        /// <devdoc>
        ///    <para>Construct a new empty schema collection.</para>
        /// </devdoc>
        public XmlSchemaCollection() : this(new NameTable()) {
        }
 
        /// <include file='doc\XmlSchemaCollection.uex' path='docs/doc[@for="XmlSchemaCollection.XmlSchemaCollection1"]/*' />
        /// <devdoc>
        ///    <para>Construct a new empty schema collection with associated XmlNameTable.
        ///       The XmlNameTable is used when loading schemas</para>
        /// </devdoc>
        public XmlSchemaCollection(XmlNameTable nametable) {
            if (nametable == null) {
                throw new ArgumentNullException("nametable");
            }
            nameTable = nametable;
            collection = Hashtable.Synchronized(new Hashtable());
            xmlResolver = System.Xml.XmlConfiguration.XmlReaderSection.CreateDefaultResolver();
            isThreadSafe = true;
            if (isThreadSafe) {
                wLock = new ReaderWriterLock();
            }
        }

        /// <include file='doc\XmlSchemaCollection.uex' path='docs/doc[@for="XmlSchemaCollection.Count"]/*' />
        /// <devdoc>
        ///    <para>Returns the number of namespaces defined in this collection
        ///       (whether or not there is an actual schema associated with those namespaces or not).</para>
        /// </devdoc>
        public int Count {
            get { return collection.Count;}
        }
 
        /// <include file='doc\XmlSchemaCollection.uex' path='docs/doc[@for="XmlSchemaCollection.NameTable"]/*' />
        /// <devdoc>
        ///    <para>The default XmlNameTable used by the XmlSchemaCollection when loading new schemas.</para>
        /// </devdoc>
        public XmlNameTable NameTable {
            get { return nameTable;}
        }

        /// <include file='doc\XmlSchemaCollection.uex' path='docs/doc[@for="XmlSchemaCollection.ValidationEventHandler"]/*' />
        public  event ValidationEventHandler ValidationEventHandler {
            add { validationEventHandler += value; }
            remove { validationEventHandler -= value; }
        }

        internal XmlResolver XmlResolver
        {
            set {
                xmlResolver = value;
            }
        }


        /// <include file='doc\XmlSchemaCollection.uex' path='docs/doc[@for="XmlSchemaCollection.Add"]/*' />
        /// <devdoc>
        ///    <para>Add the schema located by the given URL into the schema collection.
        ///       If the given schema references other namespaces, the schemas for those other
        ///       namespaces are NOT automatically loaded.</para>
        /// </devdoc>
        [ResourceConsumption(ResourceScope.Machine)]
        [ResourceExposure(ResourceScope.Machine)]
        public XmlSchema Add(string ns, string uri) {
            if (uri == null || uri.Length == 0)
                throw new ArgumentNullException("uri");
            XmlTextReader reader = new XmlTextReader(uri, nameTable);
            reader.XmlResolver = xmlResolver;

            XmlSchema schema = null;
            try {
                schema = Add(ns, reader, xmlResolver);
                while(reader.Read());// wellformness check
            }
            finally {
                reader.Close();
            }
            return schema;
        }

	/// <include file='doc\XmlSchemaCollection.uex' path='docs/doc[@for="XmlSchemaCollection.Add4"]/*' />
        public XmlSchema Add(String ns, XmlReader reader) {
	    return Add(ns, reader, xmlResolver);	
	}

        /// <include file='doc\XmlSchemaCollection.uex' path='docs/doc[@for="XmlSchemaCollection.Add1"]/*' />
        /// <devdoc>
        ///    <para>Add the given schema into the schema collection.
        ///       If the given schema references other namespaces, the schemas for those
        ///       other namespaces are NOT automatically loaded.</para>
        /// </devdoc>
        public XmlSchema Add(String ns, XmlReader reader, XmlResolver resolver) {
            if (reader == null)
                throw new ArgumentNullException("reader");
            XmlNameTable readerNameTable = reader.NameTable;
            SchemaInfo schemaInfo = new SchemaInfo(); 
	        
            Parser parser = new Parser(SchemaType.None, readerNameTable, GetSchemaNames(readerNameTable), validationEventHandler);
            parser.XmlResolver = resolver;
            SchemaType schemaType;
            try {
                schemaType = parser.Parse(reader, ns);
            }
            catch (XmlSchemaException e) {
                SendValidationEvent(e);
                return null;
            }

            if (schemaType == SchemaType.XSD) {
				schemaInfo.SchemaType = SchemaType.XSD;
                return Add(ns, schemaInfo, parser.XmlSchema, true, resolver);
            }
            else {
                SchemaInfo xdrSchema = parser.XdrSchema;
                return Add(ns, parser.XdrSchema, null, true, resolver);
            }
        }

        /// <include file='doc\XmlSchemaCollection.uex' path='docs/doc[@for="XmlSchemaCollection.Add2"]/*' />
        /// <devdoc>
        ///    <para>[To be supplied.]</para>
        /// </devdoc>
        public XmlSchema Add(XmlSchema schema) {
			return Add(schema, xmlResolver);
        }

        /// <include file='doc\XmlSchemaCollection.uex' path='docs/doc[@for="XmlSchemaCollection.Add5"]/*' />
	    public XmlSchema Add(XmlSchema schema, XmlResolver resolver) {
            if (schema == null)
                throw new ArgumentNullException("schema");

            SchemaInfo schemaInfo = new SchemaInfo(); 
            schemaInfo.SchemaType = SchemaType.XSD;
            return Add(schema.TargetNamespace, schemaInfo, schema, true, resolver);
        }

        /// <include file='doc\XmlSchemaCollection.uex' path='docs/doc[@for="XmlSchemaCollection.Add3"]/*' />
        /// <devdoc>
        ///    <para>Adds all the namespaces defined in the given collection
        ///       (including their associated schemas) to this collection.</para>
        /// </devdoc>
        public void Add(XmlSchemaCollection schema) {
            if (schema == null)
                throw new ArgumentNullException("schema");
            if (this == schema)
                return;
            IDictionaryEnumerator enumerator = schema.collection.GetEnumerator();
            while (enumerator.MoveNext()) {
                XmlSchemaCollectionNode node = (XmlSchemaCollectionNode) enumerator.Value;
                Add(node.NamespaceURI, node);
            }
        }


        /// <include file='doc\XmlSchemaCollection.uex' path='docs/doc[@for="XmlSchemaCollection.this"]/*' />
        /// <devdoc>
        ///    <para>Looks up the schema by it's associated namespace URI</para>
        /// </devdoc>
        public XmlSchema this[string ns] {
            get {
                XmlSchemaCollectionNode node = (XmlSchemaCollectionNode)collection[(ns != null) ? ns: string.Empty];
                return (node != null) ? node.Schema : null;
            }
        }

        /// <include file='doc\XmlSchemaCollection.uex' path='docs/doc[@for="XmlSchemaCollection.Contains"]/*' />
        /// <devdoc>
        ///    <para>[To be supplied.]</para>
        /// </devdoc>
        public bool Contains(XmlSchema schema) {
            if (schema == null) {
                throw new ArgumentNullException("schema");
            }
            return this[schema.TargetNamespace] != null;
        }

        /// <include file='doc\XmlSchemaCollection.uex' path='docs/doc[@for="XmlSchemaCollection.Contains1"]/*' />
        public bool Contains(string ns) {
            return collection[(ns != null) ? ns : string.Empty] != null;
        }

        /// <include file='doc\XmlSchemaCollection.uex' path='docs/doc[@for="XmlSchemaCollection.IEnumerable.GetEnumerator"]/*' />
        /// <internalonly/>
        /// <devdoc>
        /// Get a IEnumerator of the XmlSchemaCollection.
        /// </devdoc>
        IEnumerator IEnumerable.GetEnumerator() {
            return new XmlSchemaCollectionEnumerator(collection);
        }

        /// <include file='doc\XmlSchemaCollection.uex' path='docs/doc[@for="XmlSchemaCollection.GetEnumerator"]/*' />
        public XmlSchemaCollectionEnumerator GetEnumerator() {
            return new XmlSchemaCollectionEnumerator(collection);
        }

        /// <include file='doc\XmlSchemaCollection.uex' path='docs/doc[@for="XmlSchemaCollection.ICollection.CopyTo"]/*' />
        /// <internalonly/>
        void ICollection.CopyTo(Array array, int index) {
            if (array == null)
                throw new ArgumentNullException("array");
            if (index < 0)
                throw new ArgumentOutOfRangeException("index");
            for (XmlSchemaCollectionEnumerator e = this.GetEnumerator(); e.MoveNext();) {
                if (index == array.Length && array.IsFixedSize) {
                    throw new ArgumentOutOfRangeException("index");
                }
                array.SetValue(e.Current, index++);
            }
        }

        /// <include file='doc\XmlSchemaCollection.uex' path='docs/doc[@for="XmlSchemaCollection.CopyTo"]/*' />
        /// <devdoc>
        ///    <para>[To be supplied.]</para>
        /// </devdoc>
        public void CopyTo(XmlSchema[] array, int index) {
            if (array == null)
                throw new ArgumentNullException("array");
            if (index < 0)
                throw new ArgumentOutOfRangeException("index");
            for (XmlSchemaCollectionEnumerator e = this.GetEnumerator(); e.MoveNext();) {
                XmlSchema schema = e.Current;
                if (schema != null) {
                    if (index == array.Length) {
                        throw new ArgumentOutOfRangeException("index");
                    }
                    array[index++] = e.Current;
                }
            }
        }

        /// <include file='doc\XmlSchemaCollection.uex' path='docs/doc[@for="XmlSchemaCollection.ICollection.IsSynchronized"]/*' />
        /// <internalonly/>
        bool ICollection.IsSynchronized {
            get { return true; }
        }

        /// <include file='doc\XmlSchemaCollection.uex' path='docs/doc[@for="XmlSchemaCollection.ICollection.SyncRoot"]/*' />
        /// <internalonly/>
        object ICollection.SyncRoot {
            get { return this; }
        }

        /// <include file='doc\XmlSchemaCollection.uex' path='docs/doc[@for="XmlSchemaCollection.ICollection.Count"]/*' />
        /// <internalonly/>
        int ICollection.Count {
            get { return collection.Count; }
        }

        internal SchemaInfo GetSchemaInfo(string ns) {
            XmlSchemaCollectionNode node = (XmlSchemaCollectionNode)collection[(ns != null) ? ns : string.Empty];
            return (node != null) ? node.SchemaInfo : null;
        }

        internal SchemaNames GetSchemaNames(XmlNameTable nt) {
            if (nameTable != nt) {
                return new SchemaNames(nt);
            }
            else {
                if (schemaNames == null) {
                    schemaNames = new SchemaNames( nameTable );
                }
                return schemaNames;
            }
        }

        internal XmlSchema Add(string ns, SchemaInfo schemaInfo, XmlSchema schema, bool compile) {
		return Add(ns, schemaInfo, schema, compile, xmlResolver);
	}

        private XmlSchema Add(string ns, SchemaInfo schemaInfo, XmlSchema schema, bool compile, XmlResolver resolver) {
            int errorCount = 0;
            if (schema != null) {
                if (schema.ErrorCount == 0 && compile) {
					if (!schema.CompileSchema(this, resolver, schemaInfo, ns, validationEventHandler, nameTable, true)) {
						errorCount = 1;
					}
					ns = schema.TargetNamespace == null ? string.Empty : schema.TargetNamespace;
                }
				errorCount += schema.ErrorCount;
            } 
            else {
                errorCount += schemaInfo.ErrorCount;
                //ns = ns == null? string.Empty : NameTable.Add(ns);
                ns = NameTable.Add(ns); //Added without checking for ns == null, since XDR cannot have null namespace
            }
            if (errorCount == 0) {
                XmlSchemaCollectionNode node = new XmlSchemaCollectionNode();
                node.NamespaceURI = ns;
                node.SchemaInfo = schemaInfo; 
				node.Schema = schema; 
                Add(ns, node);
                return schema;
            }
            return null;
        }

        private void Add(string ns, XmlSchemaCollectionNode node) {
            if (isThreadSafe)
                wLock.AcquireWriterLock(timeout);           
            try {
                if (collection[ns] != null)
                    collection.Remove(ns);
                collection.Add(ns, node);    
            }
            finally {
                if (isThreadSafe)
                    wLock.ReleaseWriterLock();                      
            }
        }

        private void SendValidationEvent(XmlSchemaException e) {
            if (validationEventHandler != null) {
                validationEventHandler(this, new ValidationEventArgs(e));
            } 
            else {
                throw e;
            }
        }

        internal ValidationEventHandler EventHandler {
            get {
                return validationEventHandler;
            }
            set {
                validationEventHandler = value;
            }
        }
    };


    internal sealed class XmlSchemaCollectionNode {
        private String      namespaceUri;
        private SchemaInfo  schemaInfo;
        private XmlSchema   schema;

        internal String NamespaceURI {
            get { return namespaceUri;}
            set { namespaceUri = value;}
        }

        internal SchemaInfo SchemaInfo {       
            get { return schemaInfo;}
            set { schemaInfo = value;}
        }

        internal XmlSchema Schema {
            get { return schema;}
            set { schema = value;}
        }   
}


    /// <include file='doc\XmlSchemaCollection.uex' path='docs/doc[@for="XmlSchemaCollectionEnumerator"]/*' />
    /// <devdoc>
    ///    <para>[To be supplied.]</para>
    /// </devdoc>
    public sealed class XmlSchemaCollectionEnumerator: IEnumerator {
        private IDictionaryEnumerator     enumerator;

        internal XmlSchemaCollectionEnumerator( Hashtable collection ) {
            enumerator = collection.GetEnumerator();            
        }

        /// <include file='doc\XmlSchemaCollection.uex' path='docs/doc[@for="XmlSchemaCollectionEnumerator.IEnumerator.Reset"]/*' />
        /// <internalonly/>
        void IEnumerator.Reset() {
            enumerator.Reset();
        }

        /// <include file='doc\XmlSchemaCollection.uex' path='docs/doc[@for="XmlSchemaCollectionEnumerator.IEnumerator.MoveNext"]/*' />
        /// <internalonly/>
        bool IEnumerator.MoveNext() {
            return enumerator.MoveNext();
        }

        /// <include file='doc\XmlSchemaCollection.uex' path='docs/doc[@for="XmlSchemaCollectionEnumerator.MoveNext"]/*' />
        /// <devdoc>
        ///    <para>[To be supplied.]</para>
        /// </devdoc>
        public bool MoveNext() {
            return enumerator.MoveNext();
        }

        /// <include file='doc\XmlSchemaCollection.uex' path='docs/doc[@for="XmlSchemaCollectionEnumerator.IEnumerator.Current"]/*' />
        /// <internalonly/>
        object IEnumerator.Current {
            get { return this.Current; }
        }

        /// <include file='doc\XmlSchemaCollection.uex' path='docs/doc[@for="XmlSchemaCollectionEnumerator.Current"]/*' />
        /// <devdoc>
        ///    <para>[To be supplied.]</para>
        /// </devdoc>
        public XmlSchema Current {
            get {
                XmlSchemaCollectionNode n = (XmlSchemaCollectionNode)enumerator.Value;
                if (n != null)
                    return n.Schema;
                else
                    return null;
            }
        }

        internal XmlSchemaCollectionNode CurrentNode {
            get {
                XmlSchemaCollectionNode n = (XmlSchemaCollectionNode)enumerator.Value;
                return n;
            }
        }
    }
}