1 | // |
---|
2 | // Cforall Version 1.0.0 Copyright (C) 2015 University of Waterloo |
---|
3 | // |
---|
4 | // The contents of this file are covered under the licence agreement in the |
---|
5 | // file "LICENCE" distributed with Cforall. |
---|
6 | // |
---|
7 | // Node.hpp -- |
---|
8 | // |
---|
9 | // Author : Thierry Delisle |
---|
10 | // Created On : Wed May 8 10:27:04 2019 |
---|
11 | // Last Modified By : Andrew Beach |
---|
12 | // Last Modified On : Mon Jun 3 13:26:00 2019 |
---|
13 | // Update Count : 5 |
---|
14 | // |
---|
15 | |
---|
16 | #pragma once |
---|
17 | |
---|
18 | #include <cassert> |
---|
19 | #include <iosfwd> |
---|
20 | |
---|
21 | namespace ast { |
---|
22 | |
---|
23 | class Visitor; |
---|
24 | |
---|
25 | /// Base class for all AST nodes. |
---|
26 | /// Keeps both strong and weak reference counts. |
---|
27 | class Node { |
---|
28 | public: |
---|
29 | // override defaults to ensure assignment doesn't |
---|
30 | // change/share reference counts |
---|
31 | Node() = default; |
---|
32 | Node(const Node&) : strong_count(0), weak_count(0) {} |
---|
33 | Node(Node&&) : strong_count(0), weak_count(0) {} |
---|
34 | Node& operator= (const Node&) = delete; |
---|
35 | Node& operator= (Node&&) = delete; |
---|
36 | virtual ~Node() = default; |
---|
37 | |
---|
38 | virtual const Node * accept( Visitor & v ) const = 0; |
---|
39 | |
---|
40 | /// Types of node references |
---|
41 | enum class ref_type { |
---|
42 | strong, |
---|
43 | weak |
---|
44 | }; |
---|
45 | |
---|
46 | private: |
---|
47 | /// Make a copy of this node; should be overridden in subclass with more precise return type |
---|
48 | virtual Node * clone() const = 0; |
---|
49 | |
---|
50 | /// Must be copied in ALL derived classes |
---|
51 | template<typename node_t> |
---|
52 | friend node_t * mutate(const node_t * node); |
---|
53 | |
---|
54 | mutable size_t strong_count = 0; |
---|
55 | mutable size_t weak_count = 0; |
---|
56 | |
---|
57 | void increment(ref_type ref) const { |
---|
58 | switch (ref) { |
---|
59 | case ref_type::strong: strong_count++; break; |
---|
60 | case ref_type::weak : weak_count ++; break; |
---|
61 | } |
---|
62 | } |
---|
63 | |
---|
64 | void decrement(ast::Node::ref_type ref) const { |
---|
65 | switch (ref) { |
---|
66 | case ref_type::strong: strong_count--; break; |
---|
67 | case ref_type::weak : weak_count --; break; |
---|
68 | } |
---|
69 | |
---|
70 | if(!strong_count && !weak_count) { |
---|
71 | delete this; |
---|
72 | } |
---|
73 | } |
---|
74 | |
---|
75 | template< typename node_t, enum Node::ref_type ref_t > |
---|
76 | friend class ptr_base; |
---|
77 | }; |
---|
78 | |
---|
79 | // Mutate a node, non-member function to avoid static type |
---|
80 | // problems and be able to use auto return |
---|
81 | template<typename node_t> |
---|
82 | node_t * mutate( const node_t * node ) { |
---|
83 | if (node->strong_count <= 1) { |
---|
84 | return const_cast<node_t *>(node); |
---|
85 | } |
---|
86 | |
---|
87 | assertf( |
---|
88 | node->weak_count == 0, |
---|
89 | "Error: mutating node with weak references to it will invalided some references" |
---|
90 | ); |
---|
91 | return node->clone(); |
---|
92 | } |
---|
93 | |
---|
94 | std::ostream& operator<< ( std::ostream& out, const Node * node ); |
---|
95 | |
---|
96 | /// Call a visitor on a possibly-null node |
---|
97 | template<typename node_t> |
---|
98 | auto maybe_accept( const node_t * n, Visitor & v ) -> decltype( n->accept(v) ) { |
---|
99 | return n ? n->accept( v ) : nullptr; |
---|
100 | } |
---|
101 | |
---|
102 | /// Base class for the smart pointer types |
---|
103 | /// should never really be used. |
---|
104 | template< typename node_t, enum Node::ref_type ref_t > |
---|
105 | class ptr_base { |
---|
106 | public: |
---|
107 | ptr_base() : node(nullptr) {} |
---|
108 | ptr_base( const node_t * n ) : node(n) { if( node ) _inc(node); } |
---|
109 | ~ptr_base() { if( node ) { auto tmp = node; node = nullptr; _dec(tmp); } } |
---|
110 | |
---|
111 | ptr_base( const ptr_base & o ) : node(o.node) { |
---|
112 | if( node ) _inc(node); |
---|
113 | } |
---|
114 | |
---|
115 | ptr_base( ptr_base && o ) : node(o.node) { o.node = nullptr; } |
---|
116 | |
---|
117 | template< enum Node::ref_type o_ref_t > |
---|
118 | ptr_base( const ptr_base<node_t, o_ref_t> & o ) : node(o.node) { |
---|
119 | if( node ) _inc(node); |
---|
120 | } |
---|
121 | |
---|
122 | template< enum Node::ref_type o_ref_t > |
---|
123 | ptr_base( ptr_base<node_t, o_ref_t> && o ) : node(o.node) { |
---|
124 | if( node ) _inc(node); |
---|
125 | } |
---|
126 | |
---|
127 | template<typename o_node_t> |
---|
128 | ptr_base & operator=( const o_node_t * node ) { |
---|
129 | assign( strict_dynamic_cast<const node_t *, nullptr>(node) ); |
---|
130 | return *this; |
---|
131 | } |
---|
132 | |
---|
133 | ptr_base & operator=( const ptr_base & o ) { |
---|
134 | assign(o.node); |
---|
135 | return *this; |
---|
136 | } |
---|
137 | |
---|
138 | ptr_base & operator=( ptr_base && o ) { |
---|
139 | if ( node == o.node ) return *this; |
---|
140 | if ( node ) _dec(node); |
---|
141 | node = o.node; |
---|
142 | o.node = nullptr; |
---|
143 | return *this; |
---|
144 | } |
---|
145 | |
---|
146 | template< enum Node::ref_type o_ref_t > |
---|
147 | ptr_base & operator=( const ptr_base<node_t, o_ref_t> & o ) { |
---|
148 | assign(o.node); |
---|
149 | return *this; |
---|
150 | } |
---|
151 | |
---|
152 | template< enum Node::ref_type o_ref_t > |
---|
153 | ptr_base & operator=( ptr_base<node_t, o_ref_t> && o ) { |
---|
154 | assign(o.node); |
---|
155 | return *this; |
---|
156 | } |
---|
157 | |
---|
158 | const node_t * get() const { return node; } |
---|
159 | const node_t * operator->() const { return node; } |
---|
160 | const node_t & operator* () const { return *node; } |
---|
161 | explicit operator bool() const { return node; } |
---|
162 | operator const node_t * () const { return node; } |
---|
163 | |
---|
164 | /// wrapper for convenient access to dynamic_cast |
---|
165 | template<typename o_node_t> |
---|
166 | const o_node_t * as() const { return dynamic_cast<const o_node_t *>(node); } |
---|
167 | |
---|
168 | /// wrapper for convenient access to strict_dynamic_cast |
---|
169 | template<typename o_node_t> |
---|
170 | const o_node_t * strict_as() const { return strict_dynamic_cast<const o_node_t *>(node); } |
---|
171 | |
---|
172 | /// Returns a mutable version of the pointer in this node. |
---|
173 | node_t * get_and_mutate(); |
---|
174 | |
---|
175 | /// Sets this pointer to a mutated version of a pointer (possibly) owned elsehere. |
---|
176 | /// Returns a mutable version of the pointer in this node. |
---|
177 | node_t * set_and_mutate( const node_t * n ); |
---|
178 | |
---|
179 | using ptr = const node_t *; |
---|
180 | |
---|
181 | private: |
---|
182 | void assign( const node_t * other ) { |
---|
183 | if( other ) _inc(other); |
---|
184 | if( node ) _dec(node ); |
---|
185 | node = other; |
---|
186 | } |
---|
187 | |
---|
188 | void _inc( const node_t * other ); |
---|
189 | void _dec( const node_t * other ); |
---|
190 | |
---|
191 | protected: |
---|
192 | const node_t * node; |
---|
193 | }; |
---|
194 | |
---|
195 | /// Owning pointer to node |
---|
196 | template< typename node_t > |
---|
197 | using ptr = ptr_base< node_t, Node::ref_type::strong >; |
---|
198 | |
---|
199 | /// Observing pointer to node |
---|
200 | template< typename node_t > |
---|
201 | using readonly = ptr_base< node_t, Node::ref_type::weak >; |
---|
202 | } |
---|
203 | |
---|
204 | // Local Variables: // |
---|
205 | // tab-width: 4 // |
---|
206 | // mode: c++ // |
---|
207 | // compile-command: "make install" // |
---|
208 | // End: // |
---|