bundles/org.apache.tomcat/src/org/apache/tomcat/util/bcel/classfile/ClassParser.java - rap/org.apache.tomcat - Git at Google

 /*
  *  Licensed to the Apache Software Foundation (ASF) under one or more
  *  contributor license agreements.  See the NOTICE file distributed with
  *  this work for additional information regarding copyright ownership.
  *  The ASF licenses this file to You under the Apache License, Version 2.0
  *  (the "License"); you may not use this file except in compliance with
  *  the License.  You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  *  Unless required by applicable law or agreed to in writing, software
  *  distributed under the License is distributed on an "AS IS" BASIS,
  *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  *  See the License for the specific language governing permissions and
  *  limitations under the License.
  *
  */
 package org.apache.tomcat.util.bcel.classfile;

 import java.io.BufferedInputStream;
 import java.io.DataInputStream;
 import java.io.FileInputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.util.zip.ZipEntry;
 import java.util.zip.ZipFile;

 import org.apache.tomcat.util.bcel.Constants;

 /**
  * Wrapper class that parses a given Java .class file. The method <A
  * href ="#parse">parse</A> returns a <A href ="JavaClass.html">
  * JavaClass</A> object on success. When an I/O error or an
  * inconsistency occurs an appropiate exception is propagated back to
  * the caller.
  *
  * The structure and the names comply, except for a few conveniences,
  * exactly with the <A href="ftp://java.sun.com/docs/specs/vmspec.ps">
  * JVM specification 1.0</a>. See this paper for
  * further details about the structure of a bytecode file.
  *
  * @version $Id: ClassParser.java,v 1.1 2011/06/28 21:08:23 rherrmann Exp $
  * @author <A HREF="mailto:m.dahm@gmx.de">M. Dahm</A>
  */
 public final class ClassParser {

     private DataInputStream file;
     private boolean fileOwned;
     private String file_name;
     private String zip_file;
     private int class_name_index, superclass_name_index;
     private int major, minor; // Compiler version
     private int access_flags; // Access rights of parsed class
     private int[] interfaces; // Names of implemented interfaces
     private ConstantPool constant_pool; // collection of constants
     private Field[] fields; // class fields, i.e., its variables
     private Method[] methods; // methods defined in the class
     private Attribute[] attributes; // attributes defined in the class
     private boolean is_zip; // Loaded from zip file
     private static final int BUFSIZE = 8192;


     /**
      * Parse class from the given stream.
      *
      * @param file Input stream
      * @param file_name File name
      */
     public ClassParser(InputStream file, String file_name) {
         this.file_name = file_name;
         fileOwned = false;
         String clazz = file.getClass().getName(); // Not a very clean solution ...
         is_zip = clazz.startsWith("java.util.zip.") || clazz.startsWith("java.util.jar.");
         if (file instanceof DataInputStream) {
             this.file = (DataInputStream) file;
         } else {
             this.file = new DataInputStream(new BufferedInputStream(file, BUFSIZE));
         }
     }


     /**
      * Parse the given Java class file and return an object that represents
      * the contained data, i.e., constants, methods, fields and commands.
      * A <em>ClassFormatException</em> is raised, if the file is not a valid
      * .class file. (This does not include verification of the byte code as it
      * is performed by the java interpreter).
      *
      * @return Class object representing the parsed class file
      * @throws  IOException
      * @throws  ClassFormatException
      */
     public JavaClass parse() throws IOException, ClassFormatException {
         ZipFile zip = null;
         try {
             if (fileOwned) {
                 if (is_zip) {
                     zip = new ZipFile(zip_file);
                     ZipEntry entry = zip.getEntry(file_name);

                     if (entry == null) {
                         throw new IOException("File " + file_name + " not found");
                     }

                     file = new DataInputStream(new BufferedInputStream(zip.getInputStream(entry),
                             BUFSIZE));
                 } else {
                     file = new DataInputStream(new BufferedInputStream(new FileInputStream(
                             file_name), BUFSIZE));
                 }
             }
             /****************** Read headers ********************************/
             // Check magic tag of class file
             readID();
             // Get compiler version
             readVersion();
             /****************** Read constant pool and related **************/
             // Read constant pool entries
             readConstantPool();
             // Get class information
             readClassInfo();
             // Get interface information, i.e., implemented interfaces
             readInterfaces();
             /****************** Read class fields and methods ***************/
             // Read class fields, i.e., the variables of the class
             readFields();
             // Read class methods, i.e., the functions in the class
             readMethods();
             // Read class attributes
             readAttributes();
             // Check for unknown variables
             //Unknown[] u = Unknown.getUnknownAttributes();
             //for(int i=0; i < u.length; i++)
             //  System.err.println("WARNING: " + u[i]);
             // Everything should have been read now
             //      if(file.available() > 0) {
             //        int bytes = file.available();
             //        byte[] buf = new byte[bytes];
             //        file.read(buf);
             //        if(!(is_zip && (buf.length == 1))) {
             //          System.err.println("WARNING: Trailing garbage at end of " + file_name);
             //          System.err.println(bytes + " extra bytes: " + Utility.toHexString(buf));
             //        }
             //      }
         } finally {
             // Read everything of interest, so close the file
             if (fileOwned) {
                 try {
                     if (file != null) {
                         file.close();
                     }
                     if (zip != null) {
                         zip.close();
                     }
                 } catch (IOException ioe) {
                     //ignore close exceptions
                 }
             }
         }
         // Return the information we have gathered in a new object
         return new JavaClass(class_name_index, superclass_name_index, file_name, major, minor,
                 access_flags, constant_pool, interfaces, fields, methods, attributes);
     }


     /**
      * Read information about the attributes of the class.
      * @throws  IOException
      * @throws  ClassFormatException
      */
     private final void readAttributes() throws IOException, ClassFormatException {
         int attributes_count;
         attributes_count = file.readUnsignedShort();
         attributes = new Attribute[attributes_count];
         for (int i = 0; i < attributes_count; i++) {
             attributes[i] = Attribute.readAttribute(file, constant_pool);
         }
     }


     /**
      * Read information about the class and its super class.
      * @throws  IOException
      * @throws  ClassFormatException
      */
     private final void readClassInfo() throws IOException, ClassFormatException {
         access_flags = file.readUnsignedShort();
         /* Interfaces are implicitely abstract, the flag should be set
          * according to the JVM specification.
          */
         if ((access_flags & Constants.ACC_INTERFACE) != 0) {
             access_flags |= Constants.ACC_ABSTRACT;
         }
         if (((access_flags & Constants.ACC_ABSTRACT) != 0)
                 && ((access_flags & Constants.ACC_FINAL) != 0)) {
             throw new ClassFormatException("Class " + file_name + " can't be both final and abstract");
         }
         class_name_index = file.readUnsignedShort();
         superclass_name_index = file.readUnsignedShort();
     }


     /**
      * Read constant pool entries.
      * @throws  IOException
      * @throws  ClassFormatException
      */
     private final void readConstantPool() throws IOException, ClassFormatException {
         constant_pool = new ConstantPool(file);
     }


     /**
      * Read information about the fields of the class, i.e., its variables.
      * @throws  IOException
      * @throws  ClassFormatException
      */
     private final void readFields() throws IOException, ClassFormatException {
         int fields_count;
         fields_count = file.readUnsignedShort();
         fields = new Field[fields_count];
         for (int i = 0; i < fields_count; i++) {
             fields[i] = new Field(file, constant_pool);
         }
     }


     /******************** Private utility methods **********************/
     /**
      * Check whether the header of the file is ok.
      * Of course, this has to be the first action on successive file reads.
      * @throws  IOException
      * @throws  ClassFormatException
      */
     private final void readID() throws IOException, ClassFormatException {
         int magic = 0xCAFEBABE;
         if (file.readInt() != magic) {
             throw new ClassFormatException(file_name + " is not a Java .class file");
         }
     }


     /**
      * Read information about the interfaces implemented by this class.
      * @throws  IOException
      * @throws  ClassFormatException
      */
     private final void readInterfaces() throws IOException, ClassFormatException {
         int interfaces_count;
         interfaces_count = file.readUnsignedShort();
         interfaces = new int[interfaces_count];
         for (int i = 0; i < interfaces_count; i++) {
             interfaces[i] = file.readUnsignedShort();
         }
     }


     /**
      * Read information about the methods of the class.
      * @throws  IOException
      * @throws  ClassFormatException
      */
     private final void readMethods() throws IOException, ClassFormatException {
         int methods_count;
         methods_count = file.readUnsignedShort();
         methods = new Method[methods_count];
         for (int i = 0; i < methods_count; i++) {
             methods[i] = new Method(file, constant_pool);
         }
     }


     /**
      * Read major and minor version of compiler which created the file.
      * @throws  IOException
      * @throws  ClassFormatException
      */
     private final void readVersion() throws IOException, ClassFormatException {
         minor = file.readUnsignedShort();
         major = file.readUnsignedShort();
     }
 }
	/*
	* Licensed to the Apache Software Foundation (ASF) under one or more
	* contributor license agreements. See the NOTICE file distributed with
	* this work for additional information regarding copyright ownership.
	* The ASF licenses this file to You under the Apache License, Version 2.0
	* (the "License"); you may not use this file except in compliance with
	* the License. You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*
	*/
	package org.apache.tomcat.util.bcel.classfile;

	import java.io.BufferedInputStream;
	import java.io.DataInputStream;
	import java.io.FileInputStream;
	import java.io.IOException;
	import java.io.InputStream;
	import java.util.zip.ZipEntry;
	import java.util.zip.ZipFile;

	import org.apache.tomcat.util.bcel.Constants;

	/**
	* Wrapper class that parses a given Java .class file. The method <A
	* href ="#parse">parse</A> returns a <A href ="JavaClass.html">
	* JavaClass</A> object on success. When an I/O error or an
	* inconsistency occurs an appropiate exception is propagated back to
	* the caller.
	*
	* The structure and the names comply, except for a few conveniences,
	* exactly with the <A href="ftp://java.sun.com/docs/specs/vmspec.ps">
	* JVM specification 1.0</a>. See this paper for
	* further details about the structure of a bytecode file.
	*
	* @version $Id: ClassParser.java,v 1.1 2011/06/28 21:08:23 rherrmann Exp $
	* @author <A HREF="mailto:m.dahm@gmx.de">M. Dahm</A>
	*/
	public final class ClassParser {

	private DataInputStream file;
	private boolean fileOwned;
	private String file_name;
	private String zip_file;
	private int class_name_index, superclass_name_index;
	private int major, minor; // Compiler version
	private int access_flags; // Access rights of parsed class
	private int[] interfaces; // Names of implemented interfaces
	private ConstantPool constant_pool; // collection of constants
	private Field[] fields; // class fields, i.e., its variables
	private Method[] methods; // methods defined in the class
	private Attribute[] attributes; // attributes defined in the class
	private boolean is_zip; // Loaded from zip file
	private static final int BUFSIZE = 8192;


	/**
	* Parse class from the given stream.
	*
	* @param file Input stream
	* @param file_name File name
	*/
	public ClassParser(InputStream file, String file_name) {
	this.file_name = file_name;
	fileOwned = false;
	String clazz = file.getClass().getName(); // Not a very clean solution ...
	is_zip = clazz.startsWith("java.util.zip.") \|\| clazz.startsWith("java.util.jar.");
	if (file instanceof DataInputStream) {
	this.file = (DataInputStream) file;
	} else {
	this.file = new DataInputStream(new BufferedInputStream(file, BUFSIZE));
	}
	}


	/**
	* Parse the given Java class file and return an object that represents
	* the contained data, i.e., constants, methods, fields and commands.
	* A <em>ClassFormatException</em> is raised, if the file is not a valid
	* .class file. (This does not include verification of the byte code as it
	* is performed by the java interpreter).
	*
	* @return Class object representing the parsed class file
	* @throws IOException
	* @throws ClassFormatException
	*/
	public JavaClass parse() throws IOException, ClassFormatException {
	ZipFile zip = null;
	try {
	if (fileOwned) {
	if (is_zip) {
	zip = new ZipFile(zip_file);
	ZipEntry entry = zip.getEntry(file_name);

	if (entry == null) {
	throw new IOException("File " + file_name + " not found");
	}

	file = new DataInputStream(new BufferedInputStream(zip.getInputStream(entry),
	BUFSIZE));
	} else {
	file = new DataInputStream(new BufferedInputStream(new FileInputStream(
	file_name), BUFSIZE));
	}
	}
	/**************** Read headers ******************************/
	// Check magic tag of class file
	readID();
	// Get compiler version
	readVersion();
	/**************** Read constant pool and related ************/
	// Read constant pool entries
	readConstantPool();
	// Get class information
	readClassInfo();
	// Get interface information, i.e., implemented interfaces
	readInterfaces();
	/**************** Read class fields and methods *************/
	// Read class fields, i.e., the variables of the class
	readFields();
	// Read class methods, i.e., the functions in the class
	readMethods();
	// Read class attributes
	readAttributes();
	// Check for unknown variables
	//Unknown[] u = Unknown.getUnknownAttributes();
	//for(int i=0; i < u.length; i++)
	// System.err.println("WARNING: " + u[i]);
	// Everything should have been read now
	// if(file.available() > 0) {
	// int bytes = file.available();
	// byte[] buf = new byte[bytes];
	// file.read(buf);
	// if(!(is_zip && (buf.length == 1))) {
	// System.err.println("WARNING: Trailing garbage at end of " + file_name);
	// System.err.println(bytes + " extra bytes: " + Utility.toHexString(buf));
	// }
	// }
	} finally {
	// Read everything of interest, so close the file
	if (fileOwned) {
	try {
	if (file != null) {
	file.close();
	}
	if (zip != null) {
	zip.close();
	}
	} catch (IOException ioe) {
	//ignore close exceptions
	}
	}
	}
	// Return the information we have gathered in a new object
	return new JavaClass(class_name_index, superclass_name_index, file_name, major, minor,
	access_flags, constant_pool, interfaces, fields, methods, attributes);
	}


	/**
	* Read information about the attributes of the class.
	* @throws IOException
	* @throws ClassFormatException
	*/
	private final void readAttributes() throws IOException, ClassFormatException {
	int attributes_count;
	attributes_count = file.readUnsignedShort();
	attributes = new Attribute[attributes_count];
	for (int i = 0; i < attributes_count; i++) {
	attributes[i] = Attribute.readAttribute(file, constant_pool);
	}
	}


	/**
	* Read information about the class and its super class.
	* @throws IOException
	* @throws ClassFormatException
	*/
	private final void readClassInfo() throws IOException, ClassFormatException {
	access_flags = file.readUnsignedShort();
	/* Interfaces are implicitely abstract, the flag should be set
	* according to the JVM specification.
	*/
	if ((access_flags & Constants.ACC_INTERFACE) != 0) {
	access_flags \|= Constants.ACC_ABSTRACT;
	}
	if (((access_flags & Constants.ACC_ABSTRACT) != 0)
	&& ((access_flags & Constants.ACC_FINAL) != 0)) {
	throw new ClassFormatException("Class " + file_name + " can't be both final and abstract");
	}
	class_name_index = file.readUnsignedShort();
	superclass_name_index = file.readUnsignedShort();
	}


	/**
	* Read constant pool entries.
	* @throws IOException
	* @throws ClassFormatException
	*/
	private final void readConstantPool() throws IOException, ClassFormatException {
	constant_pool = new ConstantPool(file);
	}


	/**
	* Read information about the fields of the class, i.e., its variables.
	* @throws IOException
	* @throws ClassFormatException
	*/
	private final void readFields() throws IOException, ClassFormatException {
	int fields_count;
	fields_count = file.readUnsignedShort();
	fields = new Field[fields_count];
	for (int i = 0; i < fields_count; i++) {
	fields[i] = new Field(file, constant_pool);
	}
	}


	/****************** Private utility methods ********************/
	/**
	* Check whether the header of the file is ok.
	* Of course, this has to be the first action on successive file reads.
	* @throws IOException
	* @throws ClassFormatException
	*/
	private final void readID() throws IOException, ClassFormatException {
	int magic = 0xCAFEBABE;
	if (file.readInt() != magic) {
	throw new ClassFormatException(file_name + " is not a Java .class file");
	}
	}


	/**
	* Read information about the interfaces implemented by this class.
	* @throws IOException
	* @throws ClassFormatException
	*/
	private final void readInterfaces() throws IOException, ClassFormatException {
	int interfaces_count;
	interfaces_count = file.readUnsignedShort();
	interfaces = new int[interfaces_count];
	for (int i = 0; i < interfaces_count; i++) {
	interfaces[i] = file.readUnsignedShort();
	}
	}


	/**
	* Read information about the methods of the class.
	* @throws IOException
	* @throws ClassFormatException
	*/
	private final void readMethods() throws IOException, ClassFormatException {
	int methods_count;
	methods_count = file.readUnsignedShort();
	methods = new Method[methods_count];
	for (int i = 0; i < methods_count; i++) {
	methods[i] = new Method(file, constant_pool);
	}
	}


	/**
	* Read major and minor version of compiler which created the file.
	* @throws IOException
	* @throws ClassFormatException
	*/
	private final void readVersion() throws IOException, ClassFormatException {
	minor = file.readUnsignedShort();
	major = file.readUnsignedShort();
	}
	}