sundar@1232: #// Usage: jjs getclassnpe.js -- <directory>
sundar@1232: 
sundar@1232: /*
sundar@1232:  * Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.
sundar@1232:  *
sundar@1232:  * Redistribution and use in source and binary forms, with or without
sundar@1232:  * modification, are permitted provided that the following conditions
sundar@1232:  * are met:
sundar@1232:  *
sundar@1232:  *   - Redistributions of source code must retain the above copyright
sundar@1232:  *     notice, this list of conditions and the following disclaimer.
sundar@1232:  *
sundar@1232:  *   - Redistributions in binary form must reproduce the above copyright
sundar@1232:  *     notice, this list of conditions and the following disclaimer in the
sundar@1232:  *     documentation and/or other materials provided with the distribution.
sundar@1232:  *
sundar@1232:  *   - Neither the name of Oracle nor the names of its
sundar@1232:  *     contributors may be used to endorse or promote products derived
sundar@1232:  *     from this software without specific prior written permission.
sundar@1232:  *
sundar@1232:  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
sundar@1232:  * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
sundar@1232:  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
sundar@1232:  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
sundar@1232:  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
sundar@1232:  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
sundar@1232:  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
sundar@1232:  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
sundar@1232:  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
sundar@1232:  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
sundar@1232:  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
sundar@1232:  */
sundar@1232: 
sundar@1232: /*
sundar@1232:  * java.lang.Object.getClass() is sometimes used to do null check. This
sundar@1232:  * obfuscating Object.getClass() check relies on non-related intrinsic
sundar@1232:  * performance, which is potentially not available everywhere.
sundar@1232:  * See also http://cr.openjdk.java.net/~shade/scratch/NullChecks.java
sundar@1232:  * This nashorn script checks for such uses in your .java files in the
sundar@1232:  * given directory (recursively).
sundar@1232:  */
sundar@1232: 
sundar@1232: if (arguments.length == 0) {
sundar@1232:     print("Usage: jjs getclassnpe.js -- <directory>");
sundar@1232:     exit(1);
sundar@1232: }
sundar@1232: 
sundar@1232: // Java types used
sundar@1232: var File = Java.type("java.io.File");
sundar@1232: var Files = Java.type("java.nio.file.Files");
sundar@1232: var StringArray = Java.type("java.lang.String[]");
sundar@1232: var ToolProvider = Java.type("javax.tools.ToolProvider");
sundar@1232: var MethodInvocationTree = Java.type("com.sun.source.tree.MethodInvocationTree");
sundar@1232: var TreeScanner = Java.type("com.sun.source.util.TreeScanner");
sundar@1232: 
sundar@1232: // parse a specific .java file to check if it uses
sundar@1232: // Object.getClass() for null check.
sundar@1232: function checkGetClassNPE() {
sundar@1232:     // get the system compiler tool
sundar@1232:     var compiler = ToolProvider.systemJavaCompiler;
sundar@1232:     // get standard file manager
sundar@1232:     var fileMgr = compiler.getStandardFileManager(null, null, null);
sundar@1232:     // Using Java.to convert script array (arguments) to a Java String[]
sundar@1232:     var compUnits = fileMgr.getJavaFileObjects(
sundar@1232:         Java.to(arguments, StringArray));
sundar@1232:     // create a new compilation task
sundar@1232:     var task = compiler.getTask(null, fileMgr, null, null, null, compUnits);
sundar@1232:     // subclass SimpleTreeVisitor - to check for obj.getClass(); statements
sundar@1232:     var GetClassNPEChecker = Java.extend(TreeScanner);
sundar@1232: 
sundar@1232:     var visitor = new GetClassNPEChecker() {
sundar@1232:         lineMap: null,
sundar@1232:         sourceFile: null,
sundar@1232: 
sundar@1232:         // save compilation unit details for reporting
sundar@1232:         visitCompilationUnit: function(node, p) {
sundar@1232:            this.sourceFile = node.sourceFile;
sundar@1232:            this.lineMap = node.lineMap;
sundar@1232:            return Java.super(visitor).visitCompilationUnit(node, p);
sundar@1232:         },
sundar@1232: 
sundar@1232:         // look for "foo.getClass();" expression statements
sundar@1232:         visitExpressionStatement: function(node, p) {
sundar@1232:             var expr = node.expression;
sundar@1232:             if (expr instanceof MethodInvocationTree) {
sundar@1232:                 var name = String(expr.methodSelect.identifier);
sundar@1232: 
sundar@1232:                 // will match any "getClass" call with zero arguments!
sundar@1232:                 if (name == "getClass" && expr.arguments.size() == 0) {
sundar@1232:                     print(this.sourceFile.getName()
sundar@1232:                      + " @ "
sundar@1232:                      + this.lineMap.getLineNumber(node.pos)
sundar@1232:                      + ":"
sundar@1232:                      + this.lineMap.getColumnNumber(node.pos));
sundar@1232: 
sundar@1232:                     print("\t", node);
sundar@1232:                 }
sundar@1232:             }
sundar@1232:         }
sundar@1232:     }
sundar@1232: 
sundar@1232:     for each (var cu in task.parse()) {
sundar@1232:         cu.accept(visitor, null);
sundar@1232:     }
sundar@1232: }
sundar@1232: 
sundar@1232: // for each ".java" file in the directory (recursively)
sundar@1232: function main(dir) {
sundar@1232:     Files.walk(dir.toPath()).
sundar@1232:       forEach(function(p) {
sundar@1232:           var name = p.toFile().absolutePath;
sundar@1232:           if (name.endsWith(".java")) {
sundar@1232:               try {
sundar@1232:                   checkGetClassNPE(p.toFile().getAbsolutePath());
sundar@1232:               } catch (e) {
sundar@1232:                   print(e);
sundar@1232:               }
sundar@1232:           }
sundar@1232:       });
sundar@1232: }
sundar@1232: 
sundar@1232: main(new File(arguments[0]));