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 | |