content: /*******************************************************************************
   * Copyright (c) 2009, 2019 Mountainminds GmbH & Co. KG and Contributors
   * All rights reserved. This program and the accompanying materials
   * are made available under the terms of the Eclipse Public License v1.0
   * which accompanies this distribution, and is available at
   * http://www.eclipse.org/legal/epl-v10.html
   *
   * Contributors:
   *    Marc R. Hoffmann - initial API and implementation
   *    
   *******************************************************************************/
  package org.jacoco.core.runtime;
  
  import java.io.IOException;
  import java.lang.reflect.Field;
  import java.net.URL;
  import java.net.URLConnection;
  import java.net.URLStreamHandler;
  import java.util.Map;
  
  import org.jacoco.core.internal.instr.InstrSupport;
  import org.objectweb.asm.MethodVisitor;
  import org.objectweb.asm.Opcodes;
  
  /**
   * This {@link IRuntime} implementation registers a special
   * {@link URLStreamHandler} to process coverage data. The handler is not
   * actually used for opening a URL, but to get access to the runtime object.
   */
  public class URLStreamHandlerRuntime extends AbstractRuntime {
  
  	private static final String PROTOCOLPREFIX = "jacoco-";
  
  	private final String protocol;
  
  	private Map<String, URLStreamHandler> handlers;
  
  	/**
  	 * Creates a new runtime.
  	 */
  	public URLStreamHandlerRuntime() {
  		super();
  		protocol = PROTOCOLPREFIX + Integer.toHexString(hashCode());
  	}
  
  	@Override
  	public void startup(final RuntimeData data) throws Exception {
  		super.startup(data);
  		handlers = getHandlersReference();
  		handlers.put(protocol, handler);
  	}
  
  	private Map<String, URLStreamHandler> getHandlersReference()
  			throws Exception {
  		final Field field = URL.class.getDeclaredField("handlers");
  		field.setAccessible(true);
  		@SuppressWarnings("unchecked")
  		final Map<String, URLStreamHandler> map = (Map<String, URLStreamHandler>) field
  				.get(null);
  		return map;
  	}
  
  	public void shutdown() {
  		handlers.remove(protocol);
  	}
  
  	public int generateDataAccessor(final long classid, final String classname,
  			final int probecount, final MethodVisitor mv) {
  
  		// The data accessor performs the following steps:
  		//
  		// final URL url = new URL(protocol, null, "");
  		// final URLConnection connection = url.openConnection();
  		// final Object[] args = new Object[3];
  		// args[0] = Long.valueOf(classid);
  		// args[1] = classname;
  		// args[2] = Integer.valueOf(probecount);
  		// connection.equals(args);
  		// final byte[] probedata = (byte[]) args[0];
  
  		RuntimeData.generateArgumentArray(classid, classname, probecount, mv);
  		mv.visitInsn(Opcodes.DUP);
  
  		// Stack[1]: [Ljava/lang/Object;
  		// Stack[0]: [Ljava/lang/Object;
  
  		mv.visitTypeInsn(Opcodes.NEW, "java/net/URL");
  		mv.visitInsn(Opcodes.DUP);
  		mv.visitLdcInsn(protocol);
  		mv.visitInsn(Opcodes.ACONST_NULL);
  		mv.visitLdcInsn("");
  		mv.visitMethodInsn(Opcodes.INVOKESPECIAL, "java/net/URL", "<init>",
  				"(Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;)V",
  				false);
  
  		// Stack[2]: [Ljava/net/URL;
  		// Stack[1]: [Ljava/lang/Object;
  		// Stack[0]: [Ljava/lang/Object;
  
  		mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, "java/net/URL",
  				"openConnection", "()Ljava/net/URLConnection;", false);
  
  		// Stack[2]: [Ljava/net/URLConnection;
  		// Stack[1]: [Ljava/lang/Object;
  		// Stack[0]: [Ljava/lang/Object;
  
  		mv.visitInsn(Opcodes.SWAP);
  
  		// Stack[2]: [Ljava/lang/Object;
  		// Stack[1]: [Ljava/net/URLConnection;
  		// Stack[0]: [Ljava/lang/Object;
  
  		mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, "java/lang/Object", "equals",
  				"(Ljava/lang/Object;)Z", false);
  
  		// Stack[1]: Z;
  		// Stack[0]: [Ljava/lang/Object;
  
  		mv.visitInsn(Opcodes.POP);
  
  		// Stack[0]: [Ljava/lang/Object;
  
  		mv.visitInsn(Opcodes.ICONST_0);
  		mv.visitInsn(Opcodes.AALOAD);
  		mv.visitTypeInsn(Opcodes.CHECKCAST, InstrSupport.DATAFIELD_DESC);
  
  		return 7;
  	}
  
  	private final URLStreamHandler handler = new URLStreamHandler() {
  		@Override
  		protected URLConnection openConnection(final URL u) throws IOException {
  			return connection;
  		}
  	};
  
  	private final URLConnection connection = new URLConnection(null) {
  		@Override
  		public void connect() throws IOException {
  			throw new AssertionError();
  		}
  
  		@Override
  		public boolean equals(final Object obj) {
  			return data.equals(obj);
  		}
  	};
  
  }
  