checker.java

是一款用JAVA 编写的编译器 具有很强的编译功能

/*
 * Copyright 2006 Sun Microsystems, Inc.  All Rights Reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code 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
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
 * CA 95054 USA or visit www.sun.com if you need additional information or
 * have any questions.
 */

import java.io.*;
import java.util.*;
import javax.lang.model.util.*;
import javax.tools.*;
import com.sun.tools.javac.api.*;
import com.sun.source.tree.*;
import com.sun.source.util.*;
import com.sun.tools.javac.tree.JCTree;
import com.sun.tools.javac.tree.JCTree.*;
import com.sun.tools.javac.util.Position;

/*
 * Abstract class to help check the scopes in a parsed source file.
 * -- parse source file
 * -- scan trees looking for string literals
 * -- check the scope at that point against the string, using 
 *      boolean check(Scope s, String ref)
 */
abstract class Checker {
    // parse the source file and call check(scope, string) for each string literal found
    void check(String... fileNames) throws IOException {
        File testSrc = new File(System.getProperty("test.src"));
        
        DiagnosticListener<JavaFileObject> dl = new DiagnosticListener<JavaFileObject>() {
            public void report(Diagnostic d) {
                System.err.println(d);
                if (d.getKind() == Diagnostic.Kind.ERROR)
                    errors = true;
                new Exception().printStackTrace();
            }
        };
        
        JavacTool tool = JavacTool.create();
        StandardJavaFileManager fm = tool.getStandardFileManager(dl, null, null);
        Iterable<? extends JavaFileObject> files = 
            fm.getJavaFileObjectsFromFiles(getFiles(testSrc, fileNames));
        task = tool.getTask(null, fm, dl, null, null, files);
        Iterable<? extends CompilationUnitTree> units = task.parse();

        if (errors)
            throw new AssertionError("errors occurred creating trees");
        
	ScopeScanner s = new ScopeScanner();
        for (CompilationUnitTree unit: units) {
            TreePath p = new TreePath(unit);
            s.scan(p, getTrees());
        }
	task = null;
        
        if (errors)
            throw new AssertionError("errors occurred checking scopes");
    }

    // default impl: split ref at ";" and call checkLocal(scope, ref_segment) on scope and its enclosing scopes
    protected boolean check(Scope s, String ref) {
	// System.err.println("check scope: " + s);
	// System.err.println("check ref: " + ref);
	if (s == null && (ref == null || ref.trim().length() == 0))
	    return true;

	if (s == null) {
	    error(s, ref, "scope missing");
	    return false;
	}

	if (ref == null) {
	    error(s, ref, "scope unexpected");
	    return false;
	}

	String local;
	String encl;
	int semi = ref.indexOf(';');
	if (semi == -1) {
	    local = ref;
	    encl = null;
	} else {
	    local = ref.substring(0, semi);
	    encl = ref.substring(semi + 1);
	}

	return checkLocal(s, local.trim())
	    & check(s.getEnclosingScope(), encl);
    }

    // override if using default check(Scope,String)
    boolean checkLocal(Scope s, String ref) {
	throw new IllegalStateException();
    }

    void error(Scope s, String ref, String msg) { 
        System.err.println("Error: " + msg);
        System.err.println("Scope: " + (s == null ? null : asList(s.getLocalElements())));
        System.err.println("Expect: " + ref);
        System.err.println("javac: " + (s == null ? null : ((JavacScope) s).getEnv())); 
        errors = true;
    }

    protected Elements getElements() {
	return task.getElements();
    }

    protected Trees getTrees() {
	return Trees.instance(task);
    }

    boolean errors = false;
    protected JavacTask task;

    // scan a parse tree, and for every string literal found, call check(scope, string) with
    // the string value at the scope at that point
    class ScopeScanner extends TreePathScanner<Boolean,Trees> {
	public Boolean  visitLiteral(LiteralTree tree, Trees trees) {
	    TreePath path = getCurrentPath();
	    CompilationUnitTree unit = path.getCompilationUnit();
	    Position.LineMap lineMap = ((JCCompilationUnit)unit).lineMap;
//	    long line = lineMap.getLineNumber(((JCTree)tree).pos/*trees.getSourcePositions().getStartPosition(tree)*/);
//	    System.err.println(line + ": " + abbrev(tree));
	    Scope s = trees.getScope(path);
            if (tree.getKind() == Tree.Kind.STRING_LITERAL)
                check(s, tree.getValue().toString().trim());
	    return null;
	}

	private String abbrev(Tree tree) {
            int max = 48;
	    String s = tree.toString().replaceAll("[ \n]+", " ");
	    return (s.length() < max ? s : s.substring(0, max-3) + "...");
	}
    }

    // prefix filenames with a directory
    static Iterable<File> getFiles(File dir, String... names) {
	List<File> files = new ArrayList<File>(names.length);
	for (String name: names)
	    files.add(new File(dir, name));
	return files;
    }
    
    static private <T> List<T> asList(Iterable<T> iter) {
        List<T> l = new ArrayList<T>();
        for (T t: iter)
            l.add(t);
        return l;
    }
}