/*
* The Apache Software License, Version 1.1
*
*
* Copyright (c) 1999-2003 The Apache Software Foundation. All rights
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
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* the documentation and/or other materials provided with the
* distribution.
*
* 3. The end-user documentation included with the redistribution,
* if any, must include the following acknowledgment:
* "This product includes software developed by the
* Apache Software Foundation (http://www.apache.org/)."
* Alternately, this acknowledgment may appear in the software itself,
* if and wherever such third-party acknowledgments normally appear.
*
* 4. The names "Xalan" and "Apache Software Foundation" must
* not be used to endorse or promote products derived from this
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*
* 5. Products derived from this software may not be called "Apache",
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*
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation and was
* originally based on software copyright (c) 1999, Lotus
* Development Corporation., http://www.lotus.com. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*/
package org.apache.xml.utils;
import java.io.File;
import javax.xml.transform.TransformerException;
import org.apache.xml.utils.URI.MalformedURIException;
/**
* <meta name="usage" content="internal"/>
* This class is used to resolve relative URIs and SystemID
* strings into absolute URIs.
*
* <p>This is a generic utility for resolving URIs, other than the
* fact that it's declared to throw TransformerException. Please
* see code comments for details on how resolution is performed.</p>
*/
public class SystemIDResolver
{
/**
* Get an absolute URI from a given relative URI (local path).
*
* <p>The relative URI is a local filesystem path. The path can be
* absolute or relative. If it is a relative path, it is resolved relative
* to the system property "user.dir" if it is available; if not (i.e. in an
* Applet perhaps which throws SecurityException) then we just return the
* relative path. The space and backslash characters are also replaced to
* generate a good absolute URI.</p>
*
* @param localPath The relative URI to resolve
*
* @return Resolved absolute URI
*/
public static String getAbsoluteURIFromRelative(String localPath)
{
if (localPath == null || localPath.length() == 0)
return "";
// If the local path is a relative path, then it is resolved against
// the "user.dir" system property.
String absolutePath = localPath;
if (!isAbsolutePath(localPath))
{
try
{
absolutePath = getAbsolutePathFromRelativePath(localPath);
}
// user.dir not accessible from applet
catch (SecurityException se)
{
return "file:" + localPath;
}
}
String urlString;
if (null != absolutePath)
{
if (absolutePath.startsWith(File.separator))
urlString = "file://" + absolutePath;
else
urlString = "file:///" + absolutePath;
}
else
urlString = "file:" + localPath;
return replaceChars(urlString);
}
/**
* Return an absolute path from a relative path.
*
* @param relativePath A relative path
* @return The absolute path
*/
private static String getAbsolutePathFromRelativePath(String relativePath)
{
return new File(relativePath).getAbsolutePath();
}
/**
* Return true if the systemId denotes an absolute URI (contains the scheme part).
*
* @param systemId The systemId string
* @return true if the systemId contains a scheme part
*/
public static boolean isAbsoluteURI(String systemId)
{
// If there is more than one character before the ':' character,
// then it is considered to be an absolute URI; otherwise it is a local path.
int colonIndex = systemId.indexOf(':');
if (colonIndex > 1)
return true;
else
return false;
}
/**
* Return true if the local path is an absolute path.
*
* @param systemId The path string
* @return true if the path is absolute
*/
public static boolean isAbsolutePath(String systemId)
{
// On Unix, an absolute path starts with '/'.
if (systemId.startsWith(File.separator))
return true;
// On Windows, an absolute path starts with "[drive_letter]:\".
if (systemId.length() > 2
&& systemId.charAt(1) == ':'
&& Character.isLetter(systemId.charAt(0))
&& (systemId.charAt(2) == '\\' || systemId.charAt(2) == '/'))
return true;
else
return false;
}
/**
* Replace spaces with "%20" and backslashes with forward slashes in
* the input string to generate a well-formed URI string.
*
* @param str The input string
* @return The string after conversion
*/
private static String replaceChars(String str)
{
StringBuffer buf = new StringBuffer(str);
int length = buf.length();
for (int i = 0; i < length; i++)
{
char currentChar = buf.charAt(i);
// Replace space with "%20"
if (currentChar == ' ')
{
buf.setCharAt(i, '%');
buf.insert(i+1, "20");
length = length + 2;
i = i + 2;
}
// Replace backslash with forward slash
else if (currentChar == '\\')
{
buf.setCharAt(i, '/');
}
}
return buf.toString();
}
/**
* Take a SystemID string and try to turn it into a good absolute URI.
*
* @param systemId A URI string, which may be absolute or relative.
*
* @return The resolved absolute URI
*/
public static String getAbsoluteURI(String systemId)
{
String absoluteURI = systemId;
if (isAbsoluteURI(systemId))
{
// Only process the systemId if it starts with "file:".
if (systemId.startsWith("file:"))
{
String str = systemId.substring(5);
// Resolve the absolute path if the systemId starts with "file:///"
// or "file:/". Don't do anything if it only starts with "file://".
if (str != null && str.startsWith("/"))
{
if (str.startsWith("///") || !str.startsWith("//"))
{
// A Windows path containing a drive letter can be relative.
// A Unix path starting with "file:/" is always absolute.
int secondColonIndex = systemId.indexOf(':', 5);
if (secondColonIndex > 0)
{
String localPath = systemId.substring(secondColonIndex-1);
try {
if (!isAbsolutePath(localPath))
absoluteURI = systemId.substring(0, secondColonIndex-1) +
getAbsolutePathFromRelativePath(localPath);
}
catch (SecurityException se) {
return systemId;
}
}
}
}
else
{
return getAbsoluteURIFromRelative(systemId.substring(5));
}
return replaceChars(absoluteURI);
}
else
return systemId;
}
else
return getAbsoluteURIFromRelative(systemId);
}
/**
* Take a SystemID string and try to turn it into a good absolute URI.
*
* @param urlString SystemID string
* @param base The URI string used as the base for resolving the systemID
*
* @return The resolved absolute URI
* @throws TransformerException thrown if the string can't be turned into a URI.
*/
public static String getAbsoluteURI(String urlString, String base)
throws TransformerException
{
if (base == null)
return getAbsoluteURI(urlString);
String absoluteBase = getAbsoluteURI(base);
URI uri = null;
try
{
URI baseURI = new URI(absoluteBase);
uri = new URI(baseURI, urlString);
}
catch (MalformedURIException mue)
{
throw new TransformerException(mue);
}
return replaceChars(uri.toString());
}
}