/// <summary>Given a prefix mapping for a specific URI, this returns
/// the prefix mapping previously in effect for the same URI.</summary>
/// <remarks>This can be used to iterate backwards through the stack of
/// prefix mappings for a given URI.</remarks>
/// <param name="prefix"><see cref="ActiveMapping"/> instance for which
/// we want to find the instance previously in effect with the same URI.</param>
/// <returns><see cref="ActiveMapping"/> instance to look for,
/// or <c>null</c> if none exists.</returns>
public ActiveMapping PreviousUriMapping(ActiveMapping prefix)
{
string uri = prefix.Uri;
// check active mapping record
NamespaceMapping nsMapping = prefix.mappingsTop;
if (nsMapping == null || !nsMapping.declared)
{
string msg = Resources.GetString(RsId.UndeclaredMapping);
throw new XmlNamespacesException(String.Format(msg, prefix.Prefix));
}
// find a parent scope where the same URI maps to an "active" prefix
NamespaceScope scope = nsMapping.scope.parent;
while (scope != null)
{
nsMapping = scope.FindByUri(uri);
if (nsMapping != null)
{
ActiveMapping result = nsMapping.prefix;
// result must be different from prefix, since the same prefix
// cannot be "declared" with two different URIs at the same time
if (result.IsDeclared)
{
Debug.Assert(result != prefix, Resources.GetString(RsId.InternalNsError));
return(result);
}
}
scope = scope.parent;
}
return(null);
}
// Returns ActiveMapping instance properly initialized for new use,
// re-using old instance if possible.
internal ActiveMapping NewActiveMapping(string prefix)
{
if (freeActiveMappings == null)
{
return(new ActiveMapping(prefix, this));
}
else
{
ActiveMapping result = freeActiveMappings;
freeActiveMappings = result.next;
result.Init(prefix);
return(result);
}
}
/// <summary> Indicates if a mapping for a given prefix has been added
/// to this scope, even if only to "undeclare" the prefix.</summary>
/// <param name="prefix"><see cref="ActiveMapping"/> instance associated with prefix.</param>
/// <returns><c>true</c> if mapping has ben added, <c>false</c> otherwise.</returns>
public bool InScope(ActiveMapping prefix)
{
NamespaceMapping nsMapping;
Stack <NamespaceMapping> .Enumerator iter = nsMappings.GetEnumerator();
while (iter.MoveNext())
{
nsMapping = iter.Current;
if (nsMapping.prefix == prefix)
{
return(true);
}
}
return(false);
}
/// <summary>Releases all prefix mappings and returns them to the
/// associated <see cref="XmlNamespaces"/> object for re-use.</summary>
/// <remarks>Must not be called unless this instance is the most recent scope,
/// that is, is the last scope in which <see cref="AddMapping"/> was called,
/// otherwise the state of affected <see cref="ActiveMapping"/> instances
/// will get corrupted.</remarks>
protected internal void ClearMappings()
{
Debug.Assert(namespaces.IsLastScope(this), Resources.GetString(RsId.InternalNsError));
NamespaceMapping nsMapping;
ActiveMapping activeMapping;
// returns mapping records back to Namespaces for re-use
while (nsMappings.Count != 0)
{
nsMapping = (NamespaceMapping)nsMappings.Pop();
Debug.Assert(nsMapping != null, Resources.GetString(RsId.InternalNsError));
nsMapping.prefix.PopMapping();
}
// returns ActiveMapping objects back for re-use
while ((activeMapping = mappings) != null)
{
mappings = activeMapping.next;
activeMapping.Reset();
namespaces.ReturnActiveMapping(activeMapping);
}
}
/// <summary> Adds a namespace mapping to this scope.</summary>
/// <remarks>To undeclare the namespace mapping for a given prefix,
/// pass <c>null</c> as <c>uri</c> argument.</remarks>
/// <param name="prefix">Prefix part of namespace mapping.</param>
/// <param name="uri">URI part of namespace mapping.</param>
/// <returns>The newly added <see cref="NamespaceMapping"/> instance, or <c>null</c>
/// if it already exists.</returns>
protected internal NamespaceMapping AddMapping(string prefix, string uri)
{
// find prefix mapping in use
ActiveMapping activeMapping = namespaces.GetPrefixMapping(prefix);
// if not in use, re-use existing instance if possible
if (activeMapping == null)
{
activeMapping = namespaces.NewActiveMapping(prefix);
// since we have acquired an unused ActiveMapping instance we need
// to keep track of it so that we can give it back later for re-use
activeMapping.next = mappings;
mappings = activeMapping;
}
else if (InScope(activeMapping)) // duplicate found
{
return(null);
}
NamespaceMapping result = activeMapping.PushMapping(uri, this);
nsMappings.Push(result);
return(result);
}
// Accepts ActiveMapping instance that is no longer needed, storing it
// for re-use. Note: do not pass null argument - this is not checked.
internal void ReturnActiveMapping(ActiveMapping mapping)
{
mapping.next = freeActiveMappings;
freeActiveMappings = mapping;
}
// Returns ActiveMapping instance properly initialized for new use,
// re-using old instance if possible.
internal ActiveMapping NewActiveMapping(string prefix)
{
if (freeActiveMappings == null)
return new ActiveMapping(prefix, this);
else {
ActiveMapping result = freeActiveMappings;
freeActiveMappings = result.next;
result.Init(prefix);
return result;
}
}
/// <summary>Given a prefix mapping for a specific URI, this returns
/// the prefix mapping previously in effect for the same URI.</summary>
/// <remarks>This can be used to iterate backwards through the stack of
/// prefix mappings for a given URI.</remarks>
/// <param name="prefix"><see cref="ActiveMapping"/> instance for which
/// we want to find the instance previously in effect with the same URI.</param>
/// <returns><see cref="ActiveMapping"/> instance to look for,
/// or <c>null</c> if none exists.</returns>
public ActiveMapping PreviousUriMapping(ActiveMapping prefix)
{
string uri = prefix.Uri;
// check active mapping record
NamespaceMapping nsMapping = prefix.mappingsTop;
if (nsMapping == null || !nsMapping.declared) {
string msg = Resources.GetString(RsId.UndeclaredMapping);
throw new XmlNamespacesException(String.Format(msg, prefix.Prefix));
}
// find a parent scope where the same URI maps to an "active" prefix
NamespaceScope scope = nsMapping.scope.parent;
while (scope != null) {
nsMapping = scope.FindByUri(uri);
if (nsMapping != null) {
ActiveMapping result = nsMapping.prefix;
// result must be different from prefix, since the same prefix
// cannot be "declared" with two different URIs at the same time
if (result.IsDeclared) {
Debug.Assert(result != prefix, Resources.GetString(RsId.InternalNsError));
return result;
}
}
scope = scope.parent;
}
return null;
}
/// <summary>Releases all prefix mappings and returns them to the
/// associated <see cref="XmlNamespaces"/> object for re-use.</summary>
/// <remarks>Must not be called unless this instance is the most recent scope,
/// that is, is the last scope in which <see cref="AddMapping"/> was called,
/// otherwise the state of affected <see cref="ActiveMapping"/> instances
/// will get corrupted.</remarks>
protected internal void ClearMappings()
{
Debug.Assert(namespaces.IsLastScope(this), Resources.GetString(RsId.InternalNsError));
NamespaceMapping nsMapping;
ActiveMapping activeMapping;
// returns mapping records back to Namespaces for re-use
while (nsMappings.Count != 0) {
nsMapping = (NamespaceMapping)nsMappings.Pop();
Debug.Assert(nsMapping != null, Resources.GetString(RsId.InternalNsError));
nsMapping.prefix.PopMapping();
}
// returns ActiveMapping objects back for re-use
while ((activeMapping = mappings) != null) {
mappings = activeMapping.next;
activeMapping.Reset();
namespaces.ReturnActiveMapping(activeMapping);
}
}
/// <summary> Adds a namespace mapping to this scope.</summary>
/// <remarks>To undeclare the namespace mapping for a given prefix,
/// pass <c>null</c> as <c>uri</c> argument.</remarks>
/// <param name="prefix">Prefix part of namespace mapping.</param>
/// <param name="uri">URI part of namespace mapping.</param>
/// <returns>The newly added <see cref="NamespaceMapping"/> instance, or <c>null</c>
/// if it already exists.</returns>
protected internal NamespaceMapping AddMapping(string prefix, string uri)
{
// find prefix mapping in use
ActiveMapping activeMapping = namespaces.GetPrefixMapping(prefix);
// if not in use, re-use existing instance if possible
if (activeMapping == null) {
activeMapping = namespaces.NewActiveMapping(prefix);
// since we have acquired an unused ActiveMapping instance we need
// to keep track of it so that we can give it back later for re-use
activeMapping.next = mappings;
mappings = activeMapping;
}
else if (InScope(activeMapping)) // duplicate found
return null;
NamespaceMapping result = activeMapping.PushMapping(uri, this);
nsMappings.Push(result);
return result;
}
/// <summary> Indicates if a mapping for a given prefix has been added
/// to this scope, even if only to "undeclare" the prefix.</summary>
/// <param name="prefix"><see cref="ActiveMapping"/> instance associated with prefix.</param>
/// <returns><c>true</c> if mapping has ben added, <c>false</c> otherwise.</returns>
public bool InScope(ActiveMapping prefix)
{
NamespaceMapping nsMapping;
Stack<NamespaceMapping>.Enumerator iter = nsMappings.GetEnumerator();
while (iter.MoveNext()) {
nsMapping = iter.Current;
if (nsMapping.prefix == prefix)
return true;
}
return false;
}
/// <summary>Initializes <see cref="ActiveMapping"/> instance for re-use
/// with a different prefix.</summary>
/// <param name="prefix">Prefix to be associated with this instance.</param>
protected internal void Init(string prefix)
{
this.prefix = prefix;
next = null;
}
// Accepts ActiveMapping instance that is no longer needed, storing it
// for re-use. Note: do not pass null argument - this is not checked.
internal void ReturnActiveMapping(ActiveMapping mapping)
{
mapping.next = freeActiveMappings;
freeActiveMappings = mapping;
}
/// <summary>Initializes <see cref="ActiveMapping"/> instance for re-use
/// with a different prefix.</summary>
/// <param name="prefix">Prefix to be associated with this instance.</param>
protected internal void Init(string prefix)
{
this.prefix = prefix;
next = null;
}
