1 /* 2 * Copyright (c) 2015, Intel Corporation 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions are met: 6 * 7 * * Redistributions of source code must retain the above copyright notice, 8 * this list of conditions and the following disclaimer. 9 * * Redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution. 12 * * Neither the name of Intel Corporation nor the names of its contributors 13 * may be used to endorse or promote products derived from this software 14 * without specific prior written permission. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 17 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE 20 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 26 * POSSIBILITY OF SUCH DAMAGE. 27 */ 28 29 /** \file 30 * \brief Visitor base class for working with the component tree. 31 */ 32 33 #ifndef COMPONENTVISITOR_H 34 #define COMPONENTVISITOR_H 35 36 namespace ue2 { 37 38 class AsciiComponentClass; 39 class Component; 40 class ComponentAlternation; 41 class ComponentAssertion; 42 class ComponentAtomicGroup; 43 class ComponentBackReference; 44 class ComponentBoundary; 45 class ComponentByte; 46 class ComponentClass; 47 class ComponentCondReference; 48 class ComponentEmpty; 49 class ComponentEUS; 50 class ComponentRepeat; 51 class ComponentSequence; 52 class ComponentWordBoundary; 53 class UTF8ComponentClass; 54 55 /** 56 * \brief Visitor base class for working with the component tree. 57 * 58 * Our approach to implementing the visitor pattern for traversing (and 59 * optionally mutating) the Component tree for a pattern. Each _visit_ function 60 * takes a Component subclass pointer in and returns a Component pointer. That 61 * pointer can have several values, dictating what the containing Component 62 * should do: 63 * 64 * 1. If ptr == c, then do nothing. 65 * 2. If ptr == nullptr, then remove c from the tree. 66 * 3. If ptr != c && ptr != nullptr, then replace c with ptr. 67 * 68 * Traversal order is pre-order. 69 * 70 * After a Component's subcomponents have been visited, the _post_ function for 71 * that Component will be called. 72 */ 73 class ComponentVisitor { 74 public: 75 virtual ~ComponentVisitor(); 76 77 virtual Component *visit(AsciiComponentClass *c) = 0; 78 virtual Component *visit(ComponentAlternation *c) = 0; 79 virtual Component *visit(ComponentAssertion *c) = 0; 80 virtual Component *visit(ComponentAtomicGroup *c) = 0; 81 virtual Component *visit(ComponentBackReference *c) = 0; 82 virtual Component *visit(ComponentBoundary *c) = 0; 83 virtual Component *visit(ComponentByte *c) = 0; 84 virtual Component *visit(ComponentCondReference *c) = 0; 85 virtual Component *visit(ComponentEmpty *c) = 0; 86 virtual Component *visit(ComponentEUS *c) = 0; 87 virtual Component *visit(ComponentRepeat *c) = 0; 88 virtual Component *visit(ComponentSequence *c) = 0; 89 virtual Component *visit(ComponentWordBoundary *c) = 0; 90 virtual Component *visit(UTF8ComponentClass *c) = 0; 91 92 virtual void post(AsciiComponentClass *c) = 0; 93 virtual void post(ComponentAlternation *c) = 0; 94 virtual void post(ComponentAssertion *c) = 0; 95 virtual void post(ComponentAtomicGroup *c) = 0; 96 virtual void post(ComponentBackReference *c) = 0; 97 virtual void post(ComponentBoundary *c) = 0; 98 virtual void post(ComponentByte *c) = 0; 99 virtual void post(ComponentCondReference *c) = 0; 100 virtual void post(ComponentEmpty *c) = 0; 101 virtual void post(ComponentEUS *c) = 0; 102 virtual void post(ComponentRepeat *c) = 0; 103 virtual void post(ComponentSequence *c) = 0; 104 virtual void post(ComponentWordBoundary *c) = 0; 105 virtual void post(UTF8ComponentClass *c) = 0; 106 }; 107 108 /** 109 * \brief Concrete subclass of ComponentVisitor with default behaviour, 110 * allowing you to just implement the member functions you need. 111 */ 112 class DefaultComponentVisitor : public ComponentVisitor { 113 public: 114 DefaultComponentVisitor(); 115 ~DefaultComponentVisitor() override; 116 117 Component *visit(AsciiComponentClass *c) override; 118 Component *visit(ComponentAlternation *c) override; 119 Component *visit(ComponentAssertion *c) override; 120 Component *visit(ComponentAtomicGroup *c) override; 121 Component *visit(ComponentBackReference *c) override; 122 Component *visit(ComponentBoundary *c) override; 123 Component *visit(ComponentByte *c) override; 124 Component *visit(ComponentCondReference *c) override; 125 Component *visit(ComponentEmpty *c) override; 126 Component *visit(ComponentEUS *c) override; 127 Component *visit(ComponentRepeat *c) override; 128 Component *visit(ComponentSequence *c) override; 129 Component *visit(ComponentWordBoundary *c) override; 130 Component *visit(UTF8ComponentClass *c) override; 131 132 void post(AsciiComponentClass *c) override; 133 void post(ComponentAlternation *c) override; 134 void post(ComponentAssertion *c) override; 135 void post(ComponentAtomicGroup *c) override; 136 void post(ComponentBackReference *c) override; 137 void post(ComponentBoundary *c) override; 138 void post(ComponentByte *c) override; 139 void post(ComponentCondReference *c) override; 140 void post(ComponentEmpty *c) override; 141 void post(ComponentEUS *c) override; 142 void post(ComponentRepeat *c) override; 143 void post(ComponentSequence *c) override; 144 void post(ComponentWordBoundary *c) override; 145 void post(UTF8ComponentClass *c) override; 146 }; 147 148 } // namespace ue2 149 150 #endif // COMPONENTVISITOR_H 151