cfgprinter.java

一个查找java程序里bug的程序的源代码,该程序本身也是java写的,对提高java编程水平很有用

/*
 * Bytecode Analysis Framework
 * Copyright (C) 2003,2004 University of Maryland
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * 
 * This library 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
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

package edu.umd.cs.findbugs.ba;

import java.io.PrintStream;
import java.util.*;

import org.apache.bcel.classfile.ClassParser;
import org.apache.bcel.classfile.JavaClass;
import org.apache.bcel.classfile.Method;
import org.apache.bcel.generic.CodeExceptionGen;
import org.apache.bcel.generic.ConstantPoolGen;
import org.apache.bcel.generic.InstructionHandle;
import org.apache.bcel.generic.MethodGen;

/**
 * Print out a representation of a control-flow graph.
 * For debugging.
 *
 * @see CFG
 * @see CFGBuilder
 */
public class CFGPrinter {
	private CFG cfg;
	private boolean isForwards;

	public CFGPrinter(CFG cfg) {
		this.cfg = cfg;
	}

	public void setIsForwards(boolean isForwards) {
		this.isForwards = isForwards;
	}

	public void print(PrintStream out) {
		Iterator<BasicBlock> i = cfg.blockIterator();
		while (i.hasNext()) {
			BasicBlock bb = i.next();
			out.println();
			out.println("BASIC BLOCK: " + bb.getId() + (bb.isExceptionThrower() ? " [EXCEPTION THROWER]" : "") + blockStartAnnotate(bb));
			if (bb.isExceptionThrower()) {
				out.println("  Exception thrower: " + bb.getExceptionThrower());
			}
			CodeExceptionGen exceptionGen = bb.getExceptionGen();
			if (exceptionGen != null) {
				System.out.println("	CATCHES " + exceptionGen.getCatchType());
			}
			Iterator<InstructionHandle> j = instructionIterator(bb);
			while (j.hasNext()) {
				InstructionHandle handle = j.next();
				out.println(handle + instructionAnnotate(handle, bb));
			}
			out.println("END" + blockAnnotate(bb));
			Iterator<Edge> edgeIter =
				isForwards
					? cfg.outgoingEdgeIterator(bb)
					: cfg.incomingEdgeIterator(bb);
			while (edgeIter.hasNext()) {
				Edge edge = edgeIter.next();
				out.println("  " + edge.formatAsString(!isForwards) + " " + edgeAnnotate(edge));
			}
		}
	}

	public String edgeAnnotate(Edge edge) {
		return "";
	}

	public String blockStartAnnotate(BasicBlock block) {
		return "";
	}

	public String blockAnnotate(BasicBlock block) {
		return "";
	}

	public String instructionAnnotate(InstructionHandle handle, BasicBlock bb) {
		return "";
	}

	protected Iterator<InstructionHandle> instructionIterator(BasicBlock bb) {
		if (isForwards)
			return bb.instructionIterator();
		else
			return bb.instructionReverseIterator();
	}

	public static void main(String[] argv) {
		try {
			if (argv.length != 1) {
				System.out.println("Usage: " + CFGPrinter.class.getName() + " <class file>");
				System.exit(1);
			}

			String className = argv[0];
			JavaClass cls = new ClassParser(className).parse();
			RepositoryLookupFailureCallback lookupFailureCallback = new RepositoryLookupFailureCallback() {
				public void reportMissingClass(ClassNotFoundException ex) {
					ex.printStackTrace();
					System.exit(1);
				}
			};

			AnalysisContext analysisContext = new AnalysisContext(lookupFailureCallback);
			ClassContext classContext = analysisContext.getClassContext(cls);

			Method[] methods = cls.getMethods();
			String methodName = System.getProperty("cfg.method");

			for (int i = 0; i < methods.length; ++i) {
				Method method = methods[i];
				MethodGen methodGen = classContext.getMethodGen(method);
				if (methodGen == null)
					continue;

				if (methodName != null && !method.getName().equals(methodName))
					continue;

				System.out.println();
				System.out.println("----------------------------------------------------------------------------");
				System.out.println("Method " + SignatureConverter.convertMethodSignature(methodGen));
				System.out.println("----------------------------------------------------------------------------");

				CFG cfg = classContext.getCFG(method);
				CFGPrinter printer = new CFGPrinter(cfg);
				printer.print(System.out);
			}
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
}

// vim:ts=4