| 1 | /* |
|---|---|
| 2 | * Copyright (C) 2007-2010 Júlio Vilmar Gesser. |
| 3 | * Copyright (C) 2011, 2013-2020 The JavaParser Team. |
| 4 | * |
| 5 | * This file is part of JavaParser. |
| 6 | * |
| 7 | * JavaParser can be used either under the terms of |
| 8 | * a) the GNU Lesser General Public License as published by |
| 9 | * the Free Software Foundation, either version 3 of the License, or |
| 10 | * (at your option) any later version. |
| 11 | * b) the terms of the Apache License |
| 12 | * |
| 13 | * You should have received a copy of both licenses in LICENCE.LGPL and |
| 14 | * LICENCE.APACHE. Please refer to those files for details. |
| 15 | * |
| 16 | * JavaParser is distributed in the hope that it will be useful, |
| 17 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 18 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 19 | * GNU Lesser General Public License for more details. |
| 20 | */ |
| 21 | |
| 22 | package com.github.javaparser.printer.lexicalpreservation; |
| 23 | |
| 24 | import com.github.javaparser.ast.Node; |
| 25 | import com.github.javaparser.ast.observer.AstObserver; |
| 26 | import com.github.javaparser.ast.observer.AstObserverAdapter; |
| 27 | import com.github.javaparser.ast.type.UnknownType; |
| 28 | |
| 29 | import java.util.IdentityHashMap; |
| 30 | import java.util.Map; |
| 31 | |
| 32 | import static java.util.Collections.synchronizedMap; |
| 33 | |
| 34 | /** |
| 35 | * We want to recognize and ignore "phantom" nodes, like the fake type of variable in FieldDeclaration |
| 36 | */ |
| 37 | public class PhantomNodeLogic { |
| 38 | |
| 39 | private static final int LEVELS_TO_EXPLORE = 3; |
| 40 | |
| 41 | private static final Map<Node, Boolean> isPhantomNodeCache = synchronizedMap(new IdentityHashMap<>()); |
| 42 | |
| 43 | private static final AstObserver cacheCleaner = new AstObserverAdapter() { |
| 44 | @Override |
| 45 | public void parentChange(Node observedNode, Node previousParent, Node newParent) { |
| 46 | isPhantomNodeCache.remove(observedNode); |
| 47 | } |
| 48 | }; |
| 49 | |
| 50 | static boolean isPhantomNode(Node node) { |
| 51 | if (isPhantomNodeCache.containsKey(node)) { |
| 52 | return isPhantomNodeCache.get(node); |
| 53 | } else { |
| 54 | if (node instanceof UnknownType) { |
| 55 | return true; |
| 56 | } |
| 57 | boolean res = (node.getParentNode().isPresent() && |
| 58 | !node.getParentNode().get().getRange().get().contains(node.getRange().get()) |
| 59 | || inPhantomNode(node, LEVELS_TO_EXPLORE)); |
| 60 | isPhantomNodeCache.put(node, res); |
| 61 | node.register(cacheCleaner); |
| 62 | return res; |
| 63 | } |
| 64 | } |
| 65 | |
| 66 | /** |
| 67 | * A node contained in a phantom node is also a phantom node. We limit how many levels up we check just for performance reasons. |
| 68 | */ |
| 69 | private static boolean inPhantomNode(Node node, int levels) { |
| 70 | return node.getParentNode().isPresent() && |
| 71 | (isPhantomNode(node.getParentNode().get()) |
| 72 | || inPhantomNode(node.getParentNode().get(), levels - 1)); |
| 73 | } |
| 74 | |
| 75 | /** |
| 76 | * Clean up the cache used by the LexicalPreserving logic. This should only be used once you're done printing all parsed data with |
| 77 | * a JavaParser's configuration setLexicalPreservationEnabled=true. |
| 78 | */ |
| 79 | public static void cleanUpCache() { |
| 80 | isPhantomNodeCache.clear(); |
| 81 | } |
| 82 | } |
| 83 |
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