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From-SVN: r102074

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diff --git a/libjava/classpath/gnu/xml/util/Resolver.java b/libjava/classpath/gnu/xml/util/Resolver.java
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+/* Resolver.java -- 
+   Copyright (C) 1999,2000,2001 Free Software Foundation, Inc.
+
+This file is part of GNU Classpath.
+
+GNU Classpath is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2, or (at your option)
+any later version.
+
+GNU Classpath is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU Classpath; see the file COPYING.  If not, write to the
+Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+02110-1301 USA.
+
+Linking this library statically or dynamically with other modules is
+making a combined work based on this library.  Thus, the terms and
+conditions of the GNU General Public License cover the whole
+combination.
+
+As a special exception, the copyright holders of this library give you
+permission to link this library with independent modules to produce an
+executable, regardless of the license terms of these independent
+modules, and to copy and distribute the resulting executable under
+terms of your choice, provided that you also meet, for each linked
+independent module, the terms and conditions of the license of that
+module.  An independent module is a module which is not derived from
+or based on this library.  If you modify this library, you may extend
+this exception to your version of the library, but you are not
+obligated to do so.  If you do not wish to do so, delete this
+exception statement from your version. */
+
+package gnu.xml.util;
+
+import java.io.File;
+import java.io.IOException;
+import java.util.Dictionary;
+
+import org.xml.sax.EntityResolver;
+import org.xml.sax.InputSource;
+import org.xml.sax.SAXException;
+
+/**
+ * Utility implementation of a SAX resolver, which can be used to improve
+ * network utilization of SAX based XML components.  It does this by
+ * supporting local caches of external entities.
+ * SAX parsers <em>should</em> use such local caches when possible.
+ *
+ * @see XCat
+ */
+public class Resolver implements EntityResolver, Cloneable
+{
+    /**
+     * Updates a dictionary used to map PUBLIC identifiers to file names,
+     * so that it uses the mappings in a specified directory.
+     *
+     * @param mappings Array of string pairs, where the first member
+     *	of each pair is a PUBLIC identifier and the second is the
+     *	name of a file, relative to the specified directory.
+     * @param directory File holding the specified files.
+     */
+    public static void addDirectoryMapping (
+	Dictionary	table,
+	String		mappings [][],
+	File		directory
+    ) throws IOException
+    {
+	for (int i = 0; i < mappings.length; i++) {
+	    File	file = new File (directory, mappings [i][1]);
+	    String	temp;
+
+	    if (!file.exists ())	// ?? log a warning ??
+		continue;
+
+	    temp = fileToURL (file);
+	    table.put (mappings [i][0], temp);
+	}
+    }
+
+	// FIXME: these *URL routines don't quite belong here, except
+	// that they're all in the same spirit of making it easy to
+	// use local filesystem URIs with XML parsers.
+
+    /**
+     * Provides the URL for a named file, without relying on the JDK 1.2
+     * {@link java.io.File#toURL File.toURL}() utility method.
+     *
+     * @param filename the file name to convert.  Relative file names
+     *	are resolved the way the JVM resolves them (current to the
+     *	process-global current working directory).
+     *
+     * @exception IOException if the file does not exist
+     */
+    public static String fileNameToURL (String filename)
+    throws IOException
+    {
+	return fileToURL (new File (filename));
+    }
+
+    /**
+     * Provides the URL for a file, without relying on the JDK 1.2
+     * {@link java.io.File#toURL File.toURL}() utility method.
+     *
+     * @param f the file to convert.  Relative file names
+     *	are resolved the way the JVM resolves them (current to the
+     *	process-global current working directory).
+     *
+     * @exception IOException if the file does not exist
+     */
+    public static String fileToURL (File f)
+    throws IOException
+    {
+	String	temp;
+
+	// NOTE:  the javax.xml.parsers.DocumentBuilder and
+	// javax.xml.transform.stream.StreamSource versions
+	// of this don't have this test.  Some JVM versions
+	// don't report this error sanely through URL code. 
+	if (!f.exists ())
+	    throw new IOException ("no such file: " + f.getName ());
+
+	    // FIXME: getAbsolutePath() seems buggy; I'm seeing components
+	    // like "/foo/../" which are clearly not "absolute"
+	    // and should have been resolved with the filesystem.
+
+	    // Substituting "/" would be wrong, "foo" may have been
+	    // symlinked ... the URL code will make that change
+	    // later, so that things can get _really_ broken!
+
+	temp = f.getAbsolutePath ();
+
+	if (File.separatorChar != '/')
+	    temp = temp.replace (File.separatorChar, '/');
+	if (!temp.startsWith ("/"))
+	    temp = "/" + temp;
+	if (!temp.endsWith ("/") && f.isDirectory ())
+	    temp = temp + "/";
+	return "file:" + temp;
+    }
+
+
+    /**
+     * Returns a URL string.  Note that if a malformed URL is provided, or
+     * the parameter names a nonexistent file, the resulting URL may be
+     * malformed.
+     *
+     * @param fileOrURL If this is the name of a file which exists,
+     *	then its URL is returned.  Otherwise the argument is returned.
+     */
+    public static String getURL (String fileOrURL)
+    {
+	try {
+	    return fileNameToURL (fileOrURL);
+	} catch (Exception e) {
+	    return fileOrURL;
+	}
+    }
+
+
+
+    // note:  cloneable, this is just copied; unguarded against mods
+    private Dictionary		pubidMapping;
+
+    /**
+     * Constructs a resolver which understands how to map PUBLIC identifiers
+     * to other URIs, typically for local copies of standard DTD components.
+     * 
+     * @param dictionary maps PUBLIC identifiers to URIs.  This is not
+     *	copied; subsequent modifications will be reported through the
+     *	resolution operations.
+     */
+    public Resolver (Dictionary dict)
+	{ pubidMapping = dict; }
+
+    
+    // FIXME: want notion of a "system default" resolver, presumably
+    // loaded with all sorts of useful stuff.  At the same time need
+    // a notion of resolver chaining (failure --> next) so that subsystems
+    // can set up things that won't interfere with other ones.
+
+    /**
+     * This parses most MIME content type strings that have <em>charset=...</em>
+     * encoding declarations to and returns the specified encoding.  This
+     * conforms to RFC 3023, and is useful when constructing InputSource
+     * objects from URLConnection objects or other objects using MIME
+     * content typing.
+     *
+     * @param contentType the MIME content type that will be parsed; must
+     *	not be null.
+     * @return the appropriate encoding, or null if the content type is
+     *	not text and there's no <code>charset=...</code> attribute
+     */
+    static public String getEncoding (String contentType)
+    {
+	// currently a dumb parsing algorithm that works "mostly" and handles
+	//	..anything...charset=ABC
+	//	..anything...charset=ABC;otherAttr=DEF
+	//	..anything...charset=ABC (comment);otherAttr=DEF
+	//	..anything...charset= "ABC" (comment);otherAttr=DEF
+
+	int	temp;
+	String	encoding;
+	String	defValue = null;
+
+	if (contentType.startsWith ("text/"))
+	    defValue = contentType.startsWith ("text/html")
+		    ? "ISO-8859-1" : "US-ASCII";
+
+	// Assumes 'charset' is only an attribute name, not part
+	// of a value, comment, or other attribute name
+	// ALSO assumes no escaped values like "\;" or "\)"
+	if ((temp = contentType.indexOf ("charset")) != -1) {
+	    // strip out everything up to '=' ...
+	    temp = contentType.indexOf ('=', temp);
+	    if (temp == -1)
+		return defValue;
+	    encoding = contentType.substring (temp + 1);
+	    // ... and any subsequent attributes
+	    if ((temp = encoding.indexOf (';')) != -1)
+		encoding = encoding.substring (0, temp);
+	    // ... and any comments after value
+	    if ((temp = encoding.indexOf ('(')) != -1)
+		encoding = encoding.substring (0, temp);
+	    // ... then whitespace, and any (double) quotes
+	    encoding = encoding.trim ();
+	    if (encoding.charAt (0) == '"')
+		encoding = encoding.substring (1, encoding.length () - 1);
+	} else
+	    encoding = defValue;
+	return encoding;
+    }
+
+
+    /**
+     * Uses a local dictionary of public identifiers to resolve URIs,
+     * normally with the goal of minimizing network traffic or latencies.
+     */
+    public InputSource resolveEntity (String publicId, String systemId)
+    throws IOException, SAXException
+    {
+	InputSource	retval = null;
+	String		uri;
+
+	if (publicId != null
+		&& ((uri = (String) pubidMapping.get (publicId)) != null)) {
+	    retval = new InputSource (uri);
+	    retval.setPublicId (publicId);
+	}
+
+	// Could do URN resolution here
+
+	// URL resolution always done by parser
+
+	// FIXME: chain to "next" resolver
+
+	return retval;
+    }
+}