1 #// Usage: jjs exceptionswallow.js -- <directory>

     2 

     3 /*

     4  * Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.

     5  *

     6  * Redistribution and use in source and binary forms, with or without

     7  * modification, are permitted provided that the following conditions

     8  * are met:

     9  *

    10  *   - Redistributions of source code must retain the above copyright

    11  *     notice, this list of conditions and the following disclaimer.

    12  *

    13  *   - Redistributions in binary form must reproduce the above copyright

    14  *     notice, this list of conditions and the following disclaimer in the

    15  *     documentation and/or other materials provided with the distribution.

    16  *

    17  *   - Neither the name of Oracle nor the names of its

    18  *     contributors may be used to endorse or promote products derived

    19  *     from this software without specific prior written permission.

    20  *

    21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS

    22  * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,

    23  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR

    24  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR

    25  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,

    26  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,

    27  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR

    28  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF

    29  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING

    30  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS

    31  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

    32  */

    33 

    34 // This example demonstrates Java subclassing by Java.extend

    35 // and javac Compiler and Tree API. This example looks for

    36 // empty catch blocks ("exception swallow") and reports those.

    37 

    38 if (arguments.length == 0) {

    39     print("Usage: jjs exceptionswallow.js -- <directory>");

    40     exit(1);

    41 }

    42  

    43 // Java types used

    44 var File = Java.type("java.io.File");

    45 var Files = Java.type("java.nio.file.Files");

    46 var StringArray = Java.type("java.lang.String[]");

    47 var ToolProvider = Java.type("javax.tools.ToolProvider");

    48 var Tree = Java.type("com.sun.source.tree.Tree");

    49 var EmptyStatementTree = Java.type("com.sun.source.tree.EmptyStatementTree");

    50 var Trees = Java.type("com.sun.source.util.Trees");

    51 var TreeScanner = Java.type("com.sun.source.util.TreeScanner");

    52 

    53 // printEmptyCatch

    54 

    55 function printEmptyCatch() {

    56     // get the system compiler tool

    57     var compiler = ToolProvider.systemJavaCompiler;

    58     // get standard file manager

    59     var fileMgr = compiler.getStandardFileManager(null, null, null);

    60     // Using Java.to convert script array (arguments) to a Java String[]

    61     var compUnits = fileMgr.getJavaFileObjects(

    62         Java.to(arguments, StringArray));

    63     // create a new compilation task

    64     var task = compiler.getTask(null, fileMgr, null, null, null, compUnits);

    65 

    66     // SourcePositions object to get positions of AST nodes

    67     var sourcePositions = Trees.instance(task).sourcePositions;

    68 

    69     // subclass SimpleTreeVisitor - to print empty catch

    70     var EmptyCatchFinder = Java.extend(TreeScanner);

    71    

    72     function hasOnlyEmptyStats(stats) {

    73         var itr = stats.iterator();

    74         while (itr.hasNext()) {

    75             if (! (itr.next() instanceof EmptyStatementTree)) {

    76                 return false;

    77             }

    78         }

    79 

    80         return true;

    81     }

    82  

    83     var visitor = new EmptyCatchFinder() {

    84         // current CompilationUnitTree

    85         compUnit: null,

    86         // current LineMap (pos -> line, column)

    87         lineMap: null,

    88         // current compilation unit's file name

    89         fileName: null,

    90 

    91         // overrides of TreeScanner methods

    92 

    93         visitCompilationUnit: function(node, p) {

    94             // capture info about current Compilation unit

    95             this.compUnit = node;

    96             this.lineMap = node.lineMap;

    97             this.fileName = node.sourceFile.name;

    98 

    99             // Using Java.super API to call super class method here

   100             return Java.super(visitor).visitCompilationUnit(node, p);

   101         },

   102 

   103         visitCatch: function (node, p) {

   104             var stats = node.block.statements;

   105             if (stats.empty || hasOnlyEmptyStats(stats)) {

   106                 // print information on this empty catch

   107                 var pos = sourcePositions.getStartPosition(this.compUnit, node);

   108                 var line = this.lineMap.getLineNumber(pos);

   109                 var col = this.lineMap.getColumnNumber(pos);

   110                 print("Exception swallow" + " @ " + this.fileName + ":" + line + ":" + col);

   111                 // print(node);

   112             }

   113         }

   114     }

   115  

   116     for each (var cu in task.parse()) {

   117         cu.accept(visitor, null);

   118     }

   119 }

   120  

   121 // for each ".java" file in directory (recursively) and check it!

   122 function main(dir) {

   123     Files.walk(dir.toPath()).

   124       forEach(function(p) {

   125         var name = p.toFile().absolutePath;

   126         if (name.endsWith(".java")) {

   127             try {

   128                 printEmptyCatch(p.toFile().getAbsolutePath());

   129             } catch (e) {

   130                 print(e);

   131             }

   132         }

   133       });

   134 }

   135  

   136 main(new File(arguments[0]));