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

/*

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

 *

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

 * modification, are permitted provided that the following conditions

 * are met:

 *

 *   - Redistributions of source code must retain the above copyright

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

 *

 *   - Redistributions in binary form must reproduce the above copyright

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

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

 *

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

 *     contributors may be used to endorse or promote products derived

 *     from this software without specific prior written permission.

 *

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

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

 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR

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

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

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

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

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

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

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

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

 */

// This example demonstrates Java subclassing by Java.extend

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

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

if (arguments.length == 0) {

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

    exit(1);

}

// Java types used

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

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

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

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

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

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

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

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

// printEmptyCatch

function printEmptyCatch() {

    // get the system compiler tool

    var compiler = ToolProvider.systemJavaCompiler;

    // get standard file manager

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

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

    var compUnits = fileMgr.getJavaFileObjects(

        Java.to(arguments, StringArray));

    // create a new compilation task

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

    // SourcePositions object to get positions of AST nodes

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

    // subclass SimpleTreeVisitor - to print empty catch

    var EmptyCatchFinder = Java.extend(TreeScanner);

    function hasOnlyEmptyStats(stats) {

        var itr = stats.iterator();

        while (itr.hasNext()) {

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

                return false;

            }

        }

        return true;

    }

    var visitor = new EmptyCatchFinder() {

        // current CompilationUnitTree

        compUnit: null,

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

        lineMap: null,

        // current compilation unit's file name

        fileName: null,

        // overrides of TreeScanner methods

        visitCompilationUnit: function(node, p) {

            // capture info about current Compilation unit

            this.compUnit = node;

            this.lineMap = node.lineMap;

            this.fileName = node.sourceFile.name;

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

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

        },

        visitCatch: function (node, p) {

            var stats = node.block.statements;

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

                // print information on this empty catch

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

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

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

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

                // print(node);

            }

        }

    }

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

        cu.accept(visitor, null);

    }

}

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

function main(dir) {

    Files.walk(dir.toPath()).

      forEach(function(p) {

        var name = p.toFile().absolutePath;

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

            try {

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

            } catch (e) {

                print(e);

            }

        }

      });

}

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