// ==++==
// 
//   Copyright (c) Microsoft Corporation.  All rights reserved.
// 
// ==--==
// <OWNER>Microsoft</OWNER>
// 
 
//
// ExcCanonicalXml.cs
//
 
namespace System.Security.Cryptography.Xml {
    using System.Xml;
    using System.IO;
    using System.Text;
    using System.Collections;
 
    internal class ExcCanonicalXml {
        private CanonicalXmlDocument m_c14nDoc;
        private ExcAncestralNamespaceContextManager m_ancMgr;
 
        internal ExcCanonicalXml(Stream inputStream, bool includeComments, string inclusiveNamespacesPrefixList, XmlResolver resolver, string strBaseUri) {
            if (inputStream == null)
                throw new ArgumentNullException("inputStream");
 
            m_c14nDoc = new CanonicalXmlDocument(true, includeComments);
            m_c14nDoc.XmlResolver = resolver;
            m_c14nDoc.Load(Utils.PreProcessStreamInput(inputStream, resolver, strBaseUri));
            m_ancMgr = new ExcAncestralNamespaceContextManager(inclusiveNamespacesPrefixList);
        }
 
        internal ExcCanonicalXml(XmlDocument document, bool includeComments, string inclusiveNamespacesPrefixList, XmlResolver resolver) {
            if (document == null)
                throw new ArgumentNullException("document");
 
            m_c14nDoc = new CanonicalXmlDocument(true, includeComments);
            m_c14nDoc.XmlResolver = resolver;
            m_c14nDoc.Load(new XmlNodeReader(document));
            m_ancMgr = new ExcAncestralNamespaceContextManager(inclusiveNamespacesPrefixList);
        }
 
        internal ExcCanonicalXml(XmlNodeList nodeList, bool includeComments, string inclusiveNamespacesPrefixList, XmlResolver resolver) {
            if (nodeList == null)
                throw new ArgumentNullException("nodeList");
 
            XmlDocument doc = Utils.GetOwnerDocument(nodeList);
            if (doc == null)
                throw new ArgumentException("nodeList");
 
            m_c14nDoc = new CanonicalXmlDocument(false, includeComments);
            m_c14nDoc.XmlResolver = resolver;
            m_c14nDoc.Load(new XmlNodeReader(doc));
            m_ancMgr = new ExcAncestralNamespaceContextManager(inclusiveNamespacesPrefixList);
 
            MarkInclusionStateForNodes(nodeList, doc, m_c14nDoc);
        }
 
        internal byte[] GetBytes() {
            StringBuilder sb = new StringBuilder();
            m_c14nDoc.Write(sb, DocPosition.BeforeRootElement, m_ancMgr);
            UTF8Encoding utf8 = new UTF8Encoding(false);
            return utf8.GetBytes(sb.ToString());
        }
 
        internal byte[] GetDigestedBytes(HashAlgorithm hash) {
            m_c14nDoc.WriteHash(hash, DocPosition.BeforeRootElement, m_ancMgr);
            hash.TransformFinalBlock(new byte[0], 0, 0);
            byte[] res = (byte[]) hash.Hash.Clone();
            // reinitialize the hash so it is still usable after the call
            hash.Initialize();
            return res;
        }
 
        private static void MarkInclusionStateForNodes(XmlNodeList nodeList, XmlDocument inputRoot, XmlDocument root) {
            CanonicalXmlNodeList elementList = new CanonicalXmlNodeList();
            CanonicalXmlNodeList elementListCanonical = new CanonicalXmlNodeList();
            elementList.Add(inputRoot);
            elementListCanonical.Add(root);
            int index = 0;
 
            do {
                XmlNode currentNode = (XmlNode) elementList[index];
                XmlNode currentNodeCanonical = (XmlNode) elementListCanonical[index];
                XmlNodeList childNodes = currentNode.ChildNodes;
                XmlNodeList childNodesCanonical = currentNodeCanonical.ChildNodes;
                for (int i = 0; i < childNodes.Count; i++) {
                    elementList.Add(childNodes[i]);
                    elementListCanonical.Add(childNodesCanonical[i]);
 
                    if (Utils.NodeInList(childNodes[i], nodeList)) {
                        MarkNodeAsIncluded(childNodesCanonical[i]);
                    }
 
                    XmlAttributeCollection attribNodes = childNodes[i].Attributes;
                    if (attribNodes != null) {
                        for (int j = 0; j < attribNodes.Count; j++) {
                            if (Utils.NodeInList(attribNodes[j], nodeList)) {
                                MarkNodeAsIncluded(childNodesCanonical[i].Attributes.Item(j));
                            }
                        }
                    }
                }
                index++;
            } while (index < elementList.Count);
        }
 
        static void MarkNodeAsIncluded(XmlNode node) {
            if (node is ICanonicalizableNode)
               ((ICanonicalizableNode) node).IsInNodeSet = true;
        }
    }
 
    // the stack of currently active NamespaceFrame contexts. this
    // object also maintains the inclusive prefix list in a tokenized form.
    internal class ExcAncestralNamespaceContextManager : AncestralNamespaceContextManager {
        private Hashtable m_inclusivePrefixSet = null;
 
        internal ExcAncestralNamespaceContextManager(string inclusiveNamespacesPrefixList) {
            m_inclusivePrefixSet = Utils.TokenizePrefixListString(inclusiveNamespacesPrefixList);
        }
 
        private bool HasNonRedundantInclusivePrefix(XmlAttribute attr) {
            int tmp;
            string nsPrefix = Utils.GetNamespacePrefix(attr);
            return m_inclusivePrefixSet.ContainsKey(nsPrefix) &&
                Utils.IsNonRedundantNamespaceDecl(attr, GetNearestRenderedNamespaceWithMatchingPrefix(nsPrefix, out tmp));
        }
 
        private void GatherNamespaceToRender(string nsPrefix, SortedList nsListToRender, Hashtable nsLocallyDeclared) {
            foreach (object a in nsListToRender.GetKeyList()) {
                if (Utils.HasNamespacePrefix((XmlAttribute) a, nsPrefix))
                    return;
            }
 
            int rDepth;
            XmlAttribute local = (XmlAttribute) nsLocallyDeclared[nsPrefix];
            XmlAttribute rAncestral = GetNearestRenderedNamespaceWithMatchingPrefix(nsPrefix, out rDepth);
 
            if (local != null) {
                if (Utils.IsNonRedundantNamespaceDecl(local, rAncestral)) {
                    nsLocallyDeclared.Remove(nsPrefix);
                    nsListToRender.Add(local, null);
                }
            } else {
                int uDepth;
                XmlAttribute uAncestral = GetNearestUnrenderedNamespaceWithMatchingPrefix(nsPrefix, out uDepth);
                if (uAncestral != null && uDepth > rDepth && Utils.IsNonRedundantNamespaceDecl(uAncestral, rAncestral)) {
                    nsListToRender.Add(uAncestral, null);
                }
            }
        }
 
        internal override void GetNamespacesToRender (XmlElement element, SortedList attrListToRender, SortedList nsListToRender, Hashtable nsLocallyDeclared) {                
            GatherNamespaceToRender(element.Prefix, nsListToRender, nsLocallyDeclared);
            foreach (object attr in attrListToRender.GetKeyList()) {
                string prefix = ((XmlAttribute) attr).Prefix;
                if (prefix.Length > 0)
                    GatherNamespaceToRender(prefix, nsListToRender, nsLocallyDeclared);
            }
        }
    
        internal override void TrackNamespaceNode(XmlAttribute attr, SortedList nsListToRender, Hashtable nsLocallyDeclared) {
            if(!Utils.IsXmlPrefixDefinitionNode(attr)) {
                if(HasNonRedundantInclusivePrefix(attr))
                    nsListToRender.Add(attr, null);
                else
                    nsLocallyDeclared.Add(Utils.GetNamespacePrefix(attr), attr);
            }
        }
 
        internal override void TrackXmlNamespaceNode(XmlAttribute attr, SortedList nsListToRender, SortedList attrListToRender, Hashtable nsLocallyDeclared) {
            // exclusive canonicalization treats Xml namespaces as simple attributes. They are not propagated.
            attrListToRender.Add(attr, null);
        }
    }
}