Initial revision

From-SVN: r102075

libjava/classpath/vm/reference/java/lang/VMClassLoader.java

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+/* VMClassLoader.java -- Reference implementation of native interface
+   required by ClassLoader
+   Copyright (C) 1998, 2001, 2002, 2004, 2005 Free Software Foundation
+
+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 java.lang;
+
+import gnu.classpath.SystemProperties;
+
+import java.io.File;
+import java.io.IOException;
+import java.net.MalformedURLException;
+import java.net.URL;
+import java.security.ProtectionDomain;
+import java.util.Enumeration;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.StringTokenizer;
+import java.util.Vector;
+import java.util.zip.ZipFile;
+
+/**
+ * java.lang.VMClassLoader is a package-private helper for VMs to implement
+ * on behalf of java.lang.ClassLoader.
+ *
+ * @author John Keiser
+ * @author Mark Wielaard (mark@klomp.org)
+ * @author Eric Blake (ebb9@email.byu.edu)
+ */
+final class VMClassLoader
+{
+  /**
+   * Helper to define a class using a string of bytes. This assumes that
+   * the security checks have already been performed, if necessary.
+   *
+   * Implementations of this method are advised to consider the
+   * situation where user code modifies the byte array after it has
+   * been passed to defineClass.  This can be handled by making a
+   * private copy of the array, or arranging to only read any given
+   * byte a single time.
+   *
+   * @param name the name to give the class, or null if unknown
+   * @param data the data representing the classfile, in classfile format
+   * @param offset the offset into the data where the classfile starts
+   * @param len the length of the classfile data in the array
+   * @param pd the protection domain
+   * @return the class that was defined
+   * @throws ClassFormatError if data is not in proper classfile format
+   */
+  static final native Class defineClass(ClassLoader cl, String name,
+                                 byte[] data, int offset, int len,
+                                 ProtectionDomain pd)
+    throws ClassFormatError;
+
+  /**
+   * Helper to resolve all references to other classes from this class.
+   *
+   * @param c the class to resolve
+   */
+  static final native void resolveClass(Class c);
+
+  /**
+   * Helper to load a class from the bootstrap class loader.
+   *
+   * @param name the class name to load
+   * @param resolve whether to resolve it
+   * @return the class, loaded by the bootstrap classloader or null
+   * if the class wasn't found. Returning null is equivalent to throwing
+   * a ClassNotFoundException (but a possible performance optimization).
+   */
+  static final native Class loadClass(String name, boolean resolve)
+    throws ClassNotFoundException;
+
+  /**
+   * Helper to load a resource from the bootstrap class loader.
+   *
+   * @param name the resource to find
+   * @return the URL to the resource
+   */
+  static URL getResource(String name)
+  {
+    Enumeration e = getResources(name);
+    if (e.hasMoreElements())
+      return (URL)e.nextElement();
+    return null;
+  }
+
+  /**
+   * Helper to get a list of resources from the bootstrap class loader.
+   *
+   * @param name the resource to find
+   * @return an enumeration of resources
+   * @throws IOException if one occurs
+   */
+  static Enumeration getResources(String name)
+  {
+    StringTokenizer st = new StringTokenizer(
+      SystemProperties.getProperty("java.boot.class.path", "."),
+      File.pathSeparator);
+    Vector v = new Vector();
+    while (st.hasMoreTokens())
+      {
+	File file = new File(st.nextToken());
+	if (file.isDirectory())
+	  {
+	    try
+	      {
+		v.add(new URL("file://"
+		  + new File(file, name).getAbsolutePath()));
+	      }
+	    catch (MalformedURLException e)
+	      {
+		throw new Error(e);
+	      }
+	  }
+	else if (file.isFile())
+	  {
+	    ZipFile zip;
+	    try
+	      {
+		zip = new ZipFile(file);
+	      }
+	    catch (IOException e)
+	      {
+		continue;
+	      }
+	    String zname = name.startsWith("/") ? name.substring(1) : name;
+	    try
+	      {
+		if (zip.getEntry(zname) == null)
+		    continue;
+	      }
+	    finally
+	      {
+		try
+		  {
+		    zip.close();
+		  }
+		catch (IOException e)
+		  {
+		  }
+	      }
+	    try
+	      {
+		v.add(new URL("jar:file://"
+		  + file.getAbsolutePath() + "!/" + zname));
+	      }
+	    catch (MalformedURLException e)
+	      {
+		throw new Error(e);
+	      }
+	  }
+      }
+    return v.elements();
+  }
+
+  /**
+   * Helper to get a package from the bootstrap class loader.  The default
+   * implementation of returning null may be adequate, or you may decide
+   * that this needs some native help.
+   *
+   * @param name the name to find
+   * @return the named package, if it exists
+   */
+  static Package getPackage(String name)
+  {
+    return null;
+  }
+
+  /**
+   * Helper to get all packages from the bootstrap class loader.  The default
+   * implementation of returning an empty array may be adequate, or you may
+   * decide that this needs some native help.
+   *
+   * @return all named packages, if any exist
+   */
+  static Package[] getPackages()
+  {
+    return new Package[0];
+  }
+
+  /**
+   * Helper for java.lang.Integer, Byte, etc to get the TYPE class
+   * at initialization time. The type code is one of the chars that
+   * represents the primitive type as in JNI.
+   *
+   * <ul>
+   * <li>'Z' - boolean</li>
+   * <li>'B' - byte</li>
+   * <li>'C' - char</li>
+   * <li>'D' - double</li>
+   * <li>'F' - float</li>
+   * <li>'I' - int</li>
+   * <li>'J' - long</li>
+   * <li>'S' - short</li>
+   * <li>'V' - void</li>
+   * </ul>
+   *
+   * @param type the primitive type
+   * @return a "bogus" class representing the primitive type
+   */
+  static final native Class getPrimitiveClass(char type);
+
+  /**
+   * The system default for assertion status. This is used for all system
+   * classes (those with a null ClassLoader), as well as the initial value for
+   * every ClassLoader's default assertion status.
+   *
+   * XXX - Not implemented yet; this requires native help.
+   *
+   * @return the system-wide default assertion status
+   */
+  static final boolean defaultAssertionStatus()
+  {
+    return true;
+  }
+
+  /**
+   * The system default for package assertion status. This is used for all
+   * ClassLoader's packageAssertionStatus defaults. It must be a map of
+   * package names to Boolean.TRUE or Boolean.FALSE, with the unnamed package
+   * represented as a null key.
+   *
+   * XXX - Not implemented yet; this requires native help.
+   *
+   * @return a (read-only) map for the default packageAssertionStatus
+   */
+  static final Map packageAssertionStatus()
+  {
+    return new HashMap();
+  }
+
+  /**
+   * The system default for class assertion status. This is used for all
+   * ClassLoader's classAssertionStatus defaults. It must be a map of
+   * class names to Boolean.TRUE or Boolean.FALSE
+   *
+   * XXX - Not implemented yet; this requires native help.
+   *
+   * @return a (read-only) map for the default classAssertionStatus
+   */
+  static final Map classAssertionStatus()
+  {
+    return new HashMap();
+  }
+
+  static ClassLoader getSystemClassLoader()
+  {
+    return ClassLoader.defaultGetSystemClassLoader();
+  }
+}