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An OSGi bundle for Saxon-HE
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Copyright (c) 2013 Saxonica Limited.
// This Source Code Form is subject to the terms of the Mozilla Public License, v. 2.0.
// If a copy of the MPL was not distributed with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
// This Source Code Form is "Incompatible With Secondary Licenses", as defined by the Mozilla Public License, v. 2.0.
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
package net.sf.saxon.functions;
import net.sf.saxon.expr.Callable;
import net.sf.saxon.expr.Expression;
import net.sf.saxon.expr.StaticContext;
import net.sf.saxon.expr.XPathContext;
import net.sf.saxon.expr.parser.ExpressionVisitor;
import net.sf.saxon.om.Sequence;
import net.sf.saxon.trans.Err;
import net.sf.saxon.trans.XPathException;
import net.sf.saxon.value.AnyURIValue;
import net.sf.saxon.value.AtomicValue;
import net.sf.saxon.value.EmptySequence;
import java.io.File;
import java.net.MalformedURLException;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.URL;
/**
* This class supports the resolve-uri() functions in XPath 2.0
*/
public class ResolveURI extends SystemFunctionCall implements Callable {
/*@Nullable*/ String expressionBaseURI = null;
@Override
public void bindStaticContext(StaticContext env) throws XPathException {
expressionBaseURI = env.getBaseURI();
}
public void checkArguments(/*@NotNull*/ ExpressionVisitor visitor) throws XPathException {
super.checkArguments(visitor);
if (expressionBaseURI == null) {
expressionBaseURI = visitor.getStaticContext().getBaseURI();
if (expressionBaseURI == null && argument.length == 1) {
XPathException de = new XPathException("Base URI in static context of resolve-uri() is unknown");
de.setErrorCode("FONS0005");
throw de;
}
}
}
/**
* Get the static base URI of the expression
* @return the base URI from the static context
*/
/*@Nullable*/ public String getStaticBaseURI() {
return expressionBaseURI;
}
/**
* Copy an expression. This makes a deep copy.
* @return the copy of the original expression
*/
/*@NotNull*/ public Expression copy() {
ResolveURI d = (ResolveURI)super.copy();
d.expressionBaseURI = expressionBaseURI;
return d;
}
/**
* Determine whether two expressions are equivalent
*/
@Override
public boolean equals(/*@NotNull*/ Object o) {
return (o instanceof ResolveURI) &&
super.equals(o) &&
equalOrNull(expressionBaseURI, ((ResolveURI)o).expressionBaseURI);
}
/**
* Evaluate the function at run-time
*/
/*@Nullable*/ public AnyURIValue evaluateItem(XPathContext context) throws XPathException {
AtomicValue arg0 = (AtomicValue)argument[0].evaluateItem(context);
if (arg0 == null) {
return null;
}
String relative = arg0.getStringValue();
String base;
if (argument.length == 2) {
base = argument[1].evaluateAsString(context).toString();
} else {
base = expressionBaseURI;
if (expressionBaseURI == null) {
dynamicError("Base URI in static context of resolve-uri() is unknown", "FONS0005", context);
return null;
}
}
return resolve(base, relative, context);
}
/**
* Evaluate the expression
*
*
*
* @param context the dynamic evaluation context
* @param arguments the values of the arguments, supplied as SequenceIterators
* @return the result of the evaluation, in the form of a SequenceIterator
* @throws net.sf.saxon.trans.XPathException
* if a dynamic error occurs during the evaluation of the expression
*/
/*@Nullable*/ public Sequence call(XPathContext context, Sequence[] arguments) throws XPathException {
AtomicValue arg0 = (AtomicValue)arguments[0].head();
if (arg0 == null) {
return EmptySequence.getInstance();
}
String relative = arg0.getStringValue();
String base;
if (argument.length == 2) {
//noinspection ConstantConditions
base = arguments[1].head().getStringValue();
} else {
base = expressionBaseURI;
if (expressionBaseURI == null) {
dynamicError("Base URI in static context of resolve-uri() is unknown", "FONS0005", context);
return null;
}
}
return resolve(base, relative, context);
}
/*@NotNull*/ private AnyURIValue resolve(String base, String relative, XPathContext context) throws XPathException {
try {
URI absoluteURI = new URI(base);
if (!absoluteURI.isAbsolute()) {
URI relativeURI = new URI(relative);
if (relativeURI.isAbsolute()) {
return new AnyURIValue(relative);
}
dynamicError("Base URI " + Err.wrap(base) + " is not an absolute URI", "FORG0002", context);
}
if (absoluteURI.isOpaque()) {
// Special-case JAR file URLs, even though non-conformant
if (base.startsWith("jar:file:")) {
try {
URL absoluteURL = new URL(base);
URL resolved = new URL(absoluteURL, relative);
return new AnyURIValue(resolved.toString());
} catch (Exception err) {
// fall through to report error
}
}
dynamicError("Base URI " + Err.wrap(base) + " is a non-hierarchic URI", "FORG0002", context);
}
if (absoluteURI.getRawFragment() != null) {
dynamicError("Base URI " + Err.wrap(base) + " contains a fragment identifier", "FORG0002", context);
}
URI resolved = makeAbsolute(relative, base);
return new AnyURIValue(resolved.toString());
} catch (URISyntaxException err) {
dynamicError("Base URI " + Err.wrap(base) + " is invalid: " + err.getMessage(),
"FORG0002", context);
return new AnyURIValue(""); //dummy return to satisfy the language rules
}
}
/**
* If a system ID can't be parsed as a URL, try to expand it as a relative
* URI using the current directory as the base URI.
* @param systemId the supplied systemId. Null is treated as equivalent to ""
* @return the systemId itself if it is a valid URL; otherwise the result of resolving
* the systemId as a relative file name in the current working directory; or if the
* current working directory is not available (e.g. in an applet) the supplied systemId
* unchanged (except that null is treated as "").
*/
/*@NotNull*/
public static String tryToExpand(/*@Nullable*/ String systemId) {
if (systemId==null) {
systemId = "";
}
try {
new URL(systemId);
return systemId; // all is well
} catch (MalformedURLException err) {
String dir;
try {
dir = System.getProperty("user.dir");
} catch (Exception geterr) {
// this doesn't work when running an applet
return systemId;
}
if (!(dir.endsWith("/") || systemId.startsWith("/"))) {
dir = dir + '/';
}
try {
URI currentDirectoryURI = new File(dir).toURI();
URI baseURI = currentDirectoryURI.resolve(systemId);
return baseURI.toString();
} catch (Exception e) {
return systemId;
}
}
}
/**
* Construct an absolute URI from a relative URI and a base URI. The method uses the resolve
* method of the java.net.URI class, except where the base URI uses the (non-standard) "jar:" scheme,
* in which case the method used is new URL(baseURL, relativeURL).
*
* Spaces in either URI are converted to %20
*
* If no base URI is available, and the relative URI is not an absolute URI, then the current
* directory is used as a base URI.
*
* @param relativeURI the relative URI. Null is permitted provided that the base URI is an absolute URI
* @param base the base URI. Null is permitted provided that relativeURI is an absolute URI
* @return the absolutized URI
* @throws java.net.URISyntaxException if either of the strings is not a valid URI or
* if the resolution fails
*/
/*@NotNull*/
public static URI makeAbsolute(/*@Nullable*/ String relativeURI, /*@Nullable*/ String base) throws URISyntaxException {
URI absoluteURI;
// System.err.println("makeAbsolute " + relativeURI + " against base " + base);
if (relativeURI == null) {
if (base == null) {
throw new URISyntaxException("", "Relative and Base URI must not both be null");
}
absoluteURI = new URI(ResolveURI.escapeSpaces(base));
if (!absoluteURI.isAbsolute()) {
throw new URISyntaxException(base, "Relative URI not supplied, so base URI must be absolute");
} else {
return absoluteURI;
}
}
relativeURI = ResolveURI.escapeSpaces(relativeURI);
base = (base == null ? null : ResolveURI.escapeSpaces(base));
try {
if (base==null || base.length() == 0) {
absoluteURI = new URI(relativeURI);
if (!absoluteURI.isAbsolute()) {
String expandedBase = ResolveURI.tryToExpand(base);
if (!expandedBase.equals(base)) { // prevent infinite recursion
return makeAbsolute(relativeURI, expandedBase);
}
}
} else if (base != null && (base.startsWith("jar:") || base.startsWith("file:////"))) {
// jar: URIs can't be resolved by the java.net.URI class, because they don't actually
// conform with the RFC standards for hierarchic URI schemes (quite apart from not being
// a registered URI scheme). But they seem to be widely used.
// URIs starting file://// are accepted by the java.net.URI class, they are used to
// represent Windows UNC filenames. However, the java.net.URI algorithm for resolving
// a relative URI against such a base URI fails to produce a usable UNC filename (it's not
// clear whether Java is implementing RFC 3986 correctly here, it depends on interpretation).
// So we use the java.net.URL algorithm for this case too, because it works.
try {
URL baseURL = new URL(base);
URL absoluteURL = new URL(baseURL, relativeURI);
absoluteURI = absoluteURL.toURI();
// Note JDK1.5 dependency on URL.toURI()
} catch (MalformedURLException err) {
throw new URISyntaxException(base + " " + relativeURI, err.getMessage());
}
} else {
URI baseURI;
try {
baseURI = new URI(base);
} catch (URISyntaxException e) {
throw new URISyntaxException(base, "Invalid base URI: " + e.getMessage());
}
if (baseURI.getFragment() != null) {
int hash = base.indexOf('#');
if (hash >= 0) {
base = base.substring(0, hash);
}
try {
baseURI = new URI(base);
} catch (URISyntaxException e) {
throw new URISyntaxException(base, "Invalid base URI: " + e.getMessage());
}
}
try {
new URI(relativeURI); // for validation only
} catch (URISyntaxException e) {
throw new URISyntaxException(base, "Invalid relative URI: " + e.getMessage());
}
absoluteURI = (relativeURI.length() == 0 ? baseURI : baseURI.resolve(relativeURI));
}
} catch (IllegalArgumentException err0) {
// can be thrown by resolve() when given a bad URI
throw new URISyntaxException(relativeURI, "Cannot resolve URI against base " + Err.wrap(base));
}
return absoluteURI;
}
/**
* Replace spaces by %20
* @param s the input string
* @return the input string with each space replaced by %20
*/
/*@NotNull*/ public static String escapeSpaces(/*@NotNull*/ String s) {
// It's not entirely clear why we have to escape spaces by hand, and not other special characters;
// it's just that tests with a variety of filenames show that this approach seems to work.
int i = s.indexOf(' ');
if (i < 0) {
return s;
}
return (i == 0 ? "" : s.substring(0, i))
+ "%20"
+ (i == s.length()-1 ? "" : escapeSpaces(s.substring(i+1)));
}
}