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 org.objectweb.asm.MethodVisitor;
  import org.objectweb.asm.Opcodes;
  
  /**
   * This {@link IRuntime} implementation makes the execution data available
   * through a special entry in the {@link System#getProperties()} hash table. The
   * advantage is, that the instrumented classes do not get dependencies to other
   * classes than the JRE library itself.
   * 
   * This runtime may cause problems in environments with security restrictions,
   * in applications that replace the system properties or in applications that
   * fail if non-String values are placed in the system properties.
   */
  public class SystemPropertiesRuntime extends AbstractRuntime {
  
  	private static final String KEYPREFIX = "jacoco-";
  
  	private final String key;
  
  	/**
  	 * Creates a new runtime.
  	 */
  	public SystemPropertiesRuntime() {
  		super();
  		this.key = KEYPREFIX + Integer.toHexString(hashCode());
  	}
  
  	public int generateDataAccessor(final long classid, final String classname,
  			final int probecount, final MethodVisitor mv) {
  		mv.visitMethodInsn(Opcodes.INVOKESTATIC, "java/lang/System",
  				"getProperties", "()Ljava/util/Properties;", false);
  
  		// Stack[0]: Ljava/util/Properties;
  
  		mv.visitLdcInsn(key);
  
  		// Stack[1]: Ljava/lang/String;
  		// Stack[0]: Ljava/util/Properties;
  
  		mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, "java/util/Properties",
  				"get", "(Ljava/lang/Object;)Ljava/lang/Object;", false);
  
  		// Stack[0]: Ljava/lang/Object;
  
  		RuntimeData.generateAccessCall(classid, classname, probecount, mv);
  
  		// Stack[0]: [Z
  
  		return 6; // Maximum local stack size is 3
  	}
  
  	@Override
  	public void startup(final RuntimeData data) throws Exception {
  		super.startup(data);
  		System.getProperties().put(key, data);
  	}
  
  	public void shutdown() {
  		System.getProperties().remove(key);
  	}
  
  }
  