/**
* @param path
* @param pos
* @throws XmpException
*/
internal static void SkipPathDelimiter(string path, PathPosition pos)
{
if (path[pos.StepBegin] == '/')
{
// skip slash
pos.StepBegin++;
// added for Java
if (pos.StepBegin >= path.Length)
{
throw new XmpException("Empty XmpPath segment", XmpError.BADXPATH);
}
}
if (path[pos.StepBegin] == '*')
{
// skip asterisk
pos.StepBegin++;
if (pos.StepBegin >= path.Length || path[pos.StepBegin] != '[')
{
throw new XmpException("Missing '[' after '*'", XmpError.BADXPATH);
}
}
}
/**
* Parses the root node of an XMP Path, checks if namespace and prefix fit together
* and resolve the property to the base property if it is an alias.
* @param schemaNs the root namespace
* @param pos the parsing position helper
* @param expandedXPath the path to contribute to
* @throws XmpException If the path is not valid.
*/
internal static void ParseRootNode(string schemaNs, PathPosition pos, XmpPath expandedXPath)
{
while (pos.StepEnd < pos.Path.Length && "/[*".IndexOf(pos.Path[pos.StepEnd]) < 0)
{
pos.StepEnd++;
}
if (pos.StepEnd == pos.StepBegin)
{
throw new XmpException("Empty initial XmpPath step", XmpError.BADXPATH);
}
string rootProp = VerifyXPathRoot(schemaNs, pos.Path.Substring(pos.StepBegin, pos.StepEnd - pos.StepBegin));
IXmpAliasInfo aliasInfo = XmpMetaFactory.SchemaRegistry.FindAlias(rootProp);
if (aliasInfo == null)
{
// add schema xpath step
expandedXPath.Add(new XmpPathSegment(schemaNs, XmpPath.SCHEMA_NODE));
XmpPathSegment rootStep = new XmpPathSegment(rootProp, XmpPath.STRUCT_FIELD_STEP);
expandedXPath.Add(rootStep);
}
else
{
// add schema xpath step and base step of alias
expandedXPath.Add(new XmpPathSegment(aliasInfo.Namespace, XmpPath.SCHEMA_NODE));
XmpPathSegment rootStep = new XmpPathSegment(VerifyXPathRoot(aliasInfo.Namespace, aliasInfo.PropName),
XmpPath.STRUCT_FIELD_STEP);
rootStep.Alias = true;
rootStep.AliasForm = aliasInfo.AliasForm.Options;
expandedXPath.Add(rootStep);
if (aliasInfo.AliasForm.ArrayAltText)
{
XmpPathSegment qualSelectorStep = new XmpPathSegment("[?xml:lang='x-default']",
XmpPath.QUAL_SELECTOR_STEP);
qualSelectorStep.Alias = true;
qualSelectorStep.AliasForm = aliasInfo.AliasForm.Options;
expandedXPath.Add(qualSelectorStep);
}
else if (aliasInfo.AliasForm.Array)
{
XmpPathSegment indexStep = new XmpPathSegment("[1]", XmpPath.ARRAY_INDEX_STEP);
indexStep.Alias = true;
indexStep.AliasForm = aliasInfo.AliasForm.Options;
expandedXPath.Add(indexStep);
}
}
}
/**
* Parses a struct segment
* @param pos the current position in the path
* @return Retusn the segment or an errror
* @throws XmpException If the sement is empty
*/
internal static XmpPathSegment ParseStructSegment(PathPosition pos)
{
pos.NameStart = pos.StepBegin;
while (pos.StepEnd < pos.Path.Length && "/[*".IndexOf(pos.Path[pos.StepEnd]) < 0)
{
pos.StepEnd++;
}
pos.NameEnd = pos.StepEnd;
if (pos.StepEnd == pos.StepBegin)
{
throw new XmpException("Empty XmpPath segment", XmpError.BADXPATH);
}
// ! Touch up later, also changing '@' to '?'.
XmpPathSegment segment = new XmpPathSegment(pos.Path.Substring(pos.StepBegin, pos.StepEnd - pos.StepBegin),
XmpPath.STRUCT_FIELD_STEP);
return(segment);
}
/**
* Split an XmpPath expression apart at the conceptual steps, adding the
* root namespace prefix to the first property component. The schema URI is
* put in the first (0th) slot in the expanded XmpPath. Check if the top
* level component is an alias, but don't resolve it.
* <p>
* In the most verbose case steps are separated by '/', and each step can be
* of these forms:
* <dl>
* <dt>prefix:name
* <dd> A top level property or struct field.
* <dt>[index]
* <dd> An element of an array.
* <dt>[last()]
* <dd> The last element of an array.
* <dt>[fieldName="value"]
* <dd> An element in an array of structs, chosen by a field value.
* <dt>[@xml:lang="value"]
* <dd> An element in an alt-text array, chosen by the xml:lang qualifier.
* <dt>[?qualName="value"]
* <dd> An element in an array, chosen by a qualifier value.
* <dt>@xml:lang
* <dd> An xml:lang qualifier.
* <dt>?qualName
* <dd> A general qualifier.
* </dl>
* <p>
* The logic is complicated though by shorthand for arrays, the separating
* '/' and leading '*' are optional. These are all equivalent: array/*[2]
* array/[2] array*[2] array[2] All of these are broken into the 2 steps
* "array" and "[2]".
* <p>
* The value portion in the array selector forms is a string quoted by '''
* or '"'. The value may contain any character including a doubled quoting
* character. The value may be empty.
* <p>
* The syntax isn't checked, but an XML name begins with a letter or '_',
* and contains letters, digits, '.', '-', '_', and a bunch of special
* non-ASCII Unicode characters. An XML qualified name is a pair of names
* separated by a colon.
* @param schemaNs
* schema namespace
* @param path
* property name
* @return Returns the expandet XmpPath.
* @throws XmpException
* Thrown if the format is not correct somehow.
*
*/
public static XmpPath ExpandXPath(string schemaNs, string path) {
if (schemaNs == null || path == null) {
throw new XmpException("Parameter must not be null", XmpError.BADPARAM);
}
XmpPath expandedXPath = new XmpPath();
PathPosition pos = new PathPosition();
pos.Path = path;
// Pull out the first component and do some special processing on it: add the schema
// namespace prefix and and see if it is an alias. The start must be a "qualName".
ParseRootNode(schemaNs, pos, expandedXPath);
// Now continue to process the rest of the XmpPath string.
while (pos.StepEnd < path.Length) {
pos.StepBegin = pos.StepEnd;
SkipPathDelimiter(path, pos);
pos.StepEnd = pos.StepBegin;
XmpPathSegment segment = path[pos.StepBegin] != '[' ? ParseStructSegment(pos) : ParseIndexSegment(pos);
if (segment.Kind == XmpPath.STRUCT_FIELD_STEP) {
if (segment.Name[0] == '@') {
segment.Name = "?" + segment.Name.Substring(1);
if (!"?xml:lang".Equals(segment.Name)) {
throw new XmpException("Only xml:lang allowed with '@'", XmpError.BADXPATH);
}
}
if (segment.Name[0] == '?') {
pos.NameStart++;
segment.Kind = XmpPath.QUALIFIER_STEP;
}
VerifyQualName(pos.Path.Substring(pos.NameStart, pos.NameEnd - pos.NameStart));
}
else if (segment.Kind == XmpPath.FIELD_SELECTOR_STEP) {
if (segment.Name[1] == '@') {
segment.Name = "[?" + segment.Name.Substring(2);
if (!segment.Name.StartsWith("[?xml:lang=")) {
throw new XmpException("Only xml:lang allowed with '@'", XmpError.BADXPATH);
}
}
if (segment.Name[1] == '?') {
pos.NameStart++;
segment.Kind = XmpPath.QUAL_SELECTOR_STEP;
VerifyQualName(pos.Path.Substring(pos.NameStart, pos.NameEnd - pos.NameStart));
}
}
expandedXPath.Add(segment);
}
return expandedXPath;
}
/**
* Parses the root node of an XMP Path, checks if namespace and prefix fit together
* and resolve the property to the base property if it is an alias.
* @param schemaNs the root namespace
* @param pos the parsing position helper
* @param expandedXPath the path to contribute to
* @throws XmpException If the path is not valid.
*/
internal static void ParseRootNode(string schemaNs, PathPosition pos, XmpPath expandedXPath) {
while (pos.StepEnd < pos.Path.Length && "/[*".IndexOf(pos.Path[pos.StepEnd]) < 0) {
pos.StepEnd++;
}
if (pos.StepEnd == pos.StepBegin) {
throw new XmpException("Empty initial XmpPath step", XmpError.BADXPATH);
}
string rootProp = VerifyXPathRoot(schemaNs, pos.Path.Substring(pos.StepBegin, pos.StepEnd - pos.StepBegin));
IXmpAliasInfo aliasInfo = XmpMetaFactory.SchemaRegistry.FindAlias(rootProp);
if (aliasInfo == null) {
// add schema xpath step
expandedXPath.Add(new XmpPathSegment(schemaNs, XmpPath.SCHEMA_NODE));
XmpPathSegment rootStep = new XmpPathSegment(rootProp, XmpPath.STRUCT_FIELD_STEP);
expandedXPath.Add(rootStep);
}
else {
// add schema xpath step and base step of alias
expandedXPath.Add(new XmpPathSegment(aliasInfo.Namespace, XmpPath.SCHEMA_NODE));
XmpPathSegment rootStep = new XmpPathSegment(VerifyXPathRoot(aliasInfo.Namespace, aliasInfo.PropName),
XmpPath.STRUCT_FIELD_STEP);
rootStep.Alias = true;
rootStep.AliasForm = aliasInfo.AliasForm.Options;
expandedXPath.Add(rootStep);
if (aliasInfo.AliasForm.ArrayAltText) {
XmpPathSegment qualSelectorStep = new XmpPathSegment("[?xml:lang='x-default']",
XmpPath.QUAL_SELECTOR_STEP);
qualSelectorStep.Alias = true;
qualSelectorStep.AliasForm = aliasInfo.AliasForm.Options;
expandedXPath.Add(qualSelectorStep);
}
else if (aliasInfo.AliasForm.Array) {
XmpPathSegment indexStep = new XmpPathSegment("[1]", XmpPath.ARRAY_INDEX_STEP);
indexStep.Alias = true;
indexStep.AliasForm = aliasInfo.AliasForm.Options;
expandedXPath.Add(indexStep);
}
}
}
/**
* Parses an array index segment.
*
* @param pos the xmp path
* @return Returns the segment or an error
* @throws XmpException thrown on xmp path errors
*
*/
internal static XmpPathSegment ParseIndexSegment(PathPosition pos) {
XmpPathSegment segment;
pos.StepEnd++; // Look at the character after the leading '['.
if ('0' <= pos.Path[pos.StepEnd] && pos.Path[pos.StepEnd] <= '9') {
// A numeric (decimal integer) array index.
while (pos.StepEnd < pos.Path.Length && '0' <= pos.Path[pos.StepEnd] && pos.Path[pos.StepEnd] <= '9') {
pos.StepEnd++;
}
segment = new XmpPathSegment(null, XmpPath.ARRAY_INDEX_STEP);
}
else {
// Could be "[last()]" or one of the selector forms. Find the ']' or '='.
while (pos.StepEnd < pos.Path.Length && pos.Path[pos.StepEnd] != ']' && pos.Path[pos.StepEnd] != '=') {
pos.StepEnd++;
}
if (pos.StepEnd >= pos.Path.Length) {
throw new XmpException("Missing ']' or '=' for array index", XmpError.BADXPATH);
}
if (pos.Path[pos.StepEnd] == ']') {
if (!"[last()".Equals(pos.Path.Substring(pos.StepBegin, pos.StepEnd - pos.StepBegin))) {
throw new XmpException("Invalid non-numeric array index", XmpError.BADXPATH);
}
segment = new XmpPathSegment(null, XmpPath.ARRAY_LAST_STEP);
}
else {
pos.NameStart = pos.StepBegin + 1;
pos.NameEnd = pos.StepEnd;
pos.StepEnd++; // Absorb the '=', remember the quote.
char quote = pos.Path[pos.StepEnd];
if (quote != '\'' && quote != '"') {
throw new XmpException("Invalid quote in array selector", XmpError.BADXPATH);
}
pos.StepEnd++; // Absorb the leading quote.
while (pos.StepEnd < pos.Path.Length) {
if (pos.Path[pos.StepEnd] == quote) {
// check for escaped quote
if (pos.StepEnd + 1 >= pos.Path.Length || pos.Path[pos.StepEnd + 1] != quote) {
break;
}
pos.StepEnd++;
}
pos.StepEnd++;
}
if (pos.StepEnd >= pos.Path.Length) {
throw new XmpException("No terminating quote for array selector", XmpError.BADXPATH);
}
pos.StepEnd++; // Absorb the trailing quote.
// ! Touch up later, also changing '@' to '?'.
segment = new XmpPathSegment(null, XmpPath.FIELD_SELECTOR_STEP);
}
}
if (pos.StepEnd >= pos.Path.Length || pos.Path[pos.StepEnd] != ']') {
throw new XmpException("Missing ']' for array index", XmpError.BADXPATH);
}
pos.StepEnd++;
segment.Name = pos.Path.Substring(pos.StepBegin, pos.StepEnd - pos.StepBegin);
return segment;
}
/**
* Parses a struct segment
* @param pos the current position in the path
* @return Retusn the segment or an errror
* @throws XmpException If the sement is empty
*/
internal static XmpPathSegment ParseStructSegment(PathPosition pos) {
pos.NameStart = pos.StepBegin;
while (pos.StepEnd < pos.Path.Length && "/[*".IndexOf(pos.Path[pos.StepEnd]) < 0) {
pos.StepEnd++;
}
pos.NameEnd = pos.StepEnd;
if (pos.StepEnd == pos.StepBegin) {
throw new XmpException("Empty XmpPath segment", XmpError.BADXPATH);
}
// ! Touch up later, also changing '@' to '?'.
XmpPathSegment segment = new XmpPathSegment(pos.Path.Substring(pos.StepBegin, pos.StepEnd - pos.StepBegin),
XmpPath.STRUCT_FIELD_STEP);
return segment;
}
/**
* @param path
* @param pos
* @throws XmpException
*/
internal static void SkipPathDelimiter(string path, PathPosition pos) {
if (path[pos.StepBegin] == '/') {
// skip slash
pos.StepBegin++;
// added for Java
if (pos.StepBegin >= path.Length) {
throw new XmpException("Empty XmpPath segment", XmpError.BADXPATH);
}
}
if (path[pos.StepBegin] == '*') {
// skip asterisk
pos.StepBegin++;
if (pos.StepBegin >= path.Length || path[pos.StepBegin] != '[') {
throw new XmpException("Missing '[' after '*'", XmpError.BADXPATH);
}
}
}
/**
* Split an XmpPath expression apart at the conceptual steps, adding the
* root namespace prefix to the first property component. The schema URI is
* put in the first (0th) slot in the expanded XmpPath. Check if the top
* level component is an alias, but don't resolve it.
* <p>
* In the most verbose case steps are separated by '/', and each step can be
* of these forms:
* <dl>
* <dt>prefix:name
* <dd> A top level property or struct field.
* <dt>[index]
* <dd> An element of an array.
* <dt>[last()]
* <dd> The last element of an array.
* <dt>[fieldName="value"]
* <dd> An element in an array of structs, chosen by a field value.
* <dt>[@xml:lang="value"]
* <dd> An element in an alt-text array, chosen by the xml:lang qualifier.
* <dt>[?qualName="value"]
* <dd> An element in an array, chosen by a qualifier value.
* <dt>@xml:lang
* <dd> An xml:lang qualifier.
* <dt>?qualName
* <dd> A general qualifier.
* </dl>
* <p>
* The logic is complicated though by shorthand for arrays, the separating
* '/' and leading '*' are optional. These are all equivalent: array/*[2]
* array/[2] array*[2] array[2] All of these are broken into the 2 steps
* "array" and "[2]".
* <p>
* The value portion in the array selector forms is a string quoted by '''
* or '"'. The value may contain any character including a doubled quoting
* character. The value may be empty.
* <p>
* The syntax isn't checked, but an XML name begins with a letter or '_',
* and contains letters, digits, '.', '-', '_', and a bunch of special
* non-ASCII Unicode characters. An XML qualified name is a pair of names
* separated by a colon.
* @param schemaNs
* schema namespace
* @param path
* property name
* @return Returns the expandet XmpPath.
* @throws XmpException
* Thrown if the format is not correct somehow.
*
*/
public static XmpPath ExpandXPath(string schemaNs, string path)
{
if (schemaNs == null || path == null)
{
throw new XmpException("Parameter must not be null", XmpError.BADPARAM);
}
XmpPath expandedXPath = new XmpPath();
PathPosition pos = new PathPosition();
pos.Path = path;
// Pull out the first component and do some special processing on it: add the schema
// namespace prefix and and see if it is an alias. The start must be a "qualName".
ParseRootNode(schemaNs, pos, expandedXPath);
// Now continue to process the rest of the XmpPath string.
while (pos.StepEnd < path.Length)
{
pos.StepBegin = pos.StepEnd;
SkipPathDelimiter(path, pos);
pos.StepEnd = pos.StepBegin;
XmpPathSegment segment = path[pos.StepBegin] != '[' ? ParseStructSegment(pos) : ParseIndexSegment(pos);
if (segment.Kind == XmpPath.STRUCT_FIELD_STEP)
{
if (segment.Name[0] == '@')
{
segment.Name = "?" + segment.Name.Substring(1);
if (!"?xml:lang".Equals(segment.Name))
{
throw new XmpException("Only xml:lang allowed with '@'", XmpError.BADXPATH);
}
}
if (segment.Name[0] == '?')
{
pos.NameStart++;
segment.Kind = XmpPath.QUALIFIER_STEP;
}
VerifyQualName(pos.Path.Substring(pos.NameStart, pos.NameEnd - pos.NameStart));
}
else if (segment.Kind == XmpPath.FIELD_SELECTOR_STEP)
{
if (segment.Name[1] == '@')
{
segment.Name = "[?" + segment.Name.Substring(2);
if (!segment.Name.StartsWith("[?xml:lang="))
{
throw new XmpException("Only xml:lang allowed with '@'", XmpError.BADXPATH);
}
}
if (segment.Name[1] == '?')
{
pos.NameStart++;
segment.Kind = XmpPath.QUAL_SELECTOR_STEP;
VerifyQualName(pos.Path.Substring(pos.NameStart, pos.NameEnd - pos.NameStart));
}
}
expandedXPath.Add(segment);
}
return(expandedXPath);
}
/**
* Parses an array index segment.
*
* @param pos the xmp path
* @return Returns the segment or an error
* @throws XmpException thrown on xmp path errors
*
*/
internal static XmpPathSegment ParseIndexSegment(PathPosition pos)
{
XmpPathSegment segment;
pos.StepEnd++; // Look at the character after the leading '['.
if ('0' <= pos.Path[pos.StepEnd] && pos.Path[pos.StepEnd] <= '9')
{
// A numeric (decimal integer) array index.
while (pos.StepEnd < pos.Path.Length && '0' <= pos.Path[pos.StepEnd] && pos.Path[pos.StepEnd] <= '9')
{
pos.StepEnd++;
}
segment = new XmpPathSegment(null, XmpPath.ARRAY_INDEX_STEP);
}
else
{
// Could be "[last()]" or one of the selector forms. Find the ']' or '='.
while (pos.StepEnd < pos.Path.Length && pos.Path[pos.StepEnd] != ']' && pos.Path[pos.StepEnd] != '=')
{
pos.StepEnd++;
}
if (pos.StepEnd >= pos.Path.Length)
{
throw new XmpException("Missing ']' or '=' for array index", XmpError.BADXPATH);
}
if (pos.Path[pos.StepEnd] == ']')
{
if (!"[last()".Equals(pos.Path.Substring(pos.StepBegin, pos.StepEnd - pos.StepBegin)))
{
throw new XmpException("Invalid non-numeric array index", XmpError.BADXPATH);
}
segment = new XmpPathSegment(null, XmpPath.ARRAY_LAST_STEP);
}
else
{
pos.NameStart = pos.StepBegin + 1;
pos.NameEnd = pos.StepEnd;
pos.StepEnd++; // Absorb the '=', remember the quote.
char quote = pos.Path[pos.StepEnd];
if (quote != '\'' && quote != '"')
{
throw new XmpException("Invalid quote in array selector", XmpError.BADXPATH);
}
pos.StepEnd++; // Absorb the leading quote.
while (pos.StepEnd < pos.Path.Length)
{
if (pos.Path[pos.StepEnd] == quote)
{
// check for escaped quote
if (pos.StepEnd + 1 >= pos.Path.Length || pos.Path[pos.StepEnd + 1] != quote)
{
break;
}
pos.StepEnd++;
}
pos.StepEnd++;
}
if (pos.StepEnd >= pos.Path.Length)
{
throw new XmpException("No terminating quote for array selector", XmpError.BADXPATH);
}
pos.StepEnd++; // Absorb the trailing quote.
// ! Touch up later, also changing '@' to '?'.
segment = new XmpPathSegment(null, XmpPath.FIELD_SELECTOR_STEP);
}
}
if (pos.StepEnd >= pos.Path.Length || pos.Path[pos.StepEnd] != ']')
{
throw new XmpException("Missing ']' for array index", XmpError.BADXPATH);
}
pos.StepEnd++;
segment.Name = pos.Path.Substring(pos.StepBegin, pos.StepEnd - pos.StepBegin);
return(segment);
}
