[2bb4a01] | 1 | // |
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| 2 | // Cforall Version 1.0.0 Copyright (C) 2015 University of Waterloo |
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| 3 | // |
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| 4 | // The contents of this file are covered under the licence agreement in the |
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| 5 | // file "LICENCE" distributed with Cforall. |
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| 6 | // |
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| 7 | // Node.hpp -- |
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| 8 | // |
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| 9 | // Author : Thierry Delisle |
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| 10 | // Created On : Wed May 8 10:27:04 2019 |
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[1e97287] | 11 | // Last Modified By : Andrew Beach |
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| 12 | // Last Modified On : Wed May 15 16:02:00 2019 |
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| 13 | // Update Count : 3 |
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[2bb4a01] | 14 | // |
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| 15 | |
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[cedb545] | 16 | #pragma once |
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| 17 | |
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[2bb4a01] | 18 | #include <cassert> |
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| 19 | #include <iosfwd> |
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[cedb545] | 20 | |
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| 21 | namespace ast { |
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[2bb4a01] | 22 | |
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| 23 | class Visitor; |
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| 24 | |
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| 25 | /// Base class for all AST nodes. |
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| 26 | /// Keeps both strong and weak reference counts. |
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[f47f887] | 27 | class Node { |
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| 28 | public: |
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[14cebb7a] | 29 | // override defaults to ensure assignment doesn't |
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[2bb4a01] | 30 | // change/share reference counts |
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| 31 | Node() = default; |
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[6d51bd7] | 32 | Node(const Node&) : strong_count(0), weak_count(0) {} |
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| 33 | Node(Node&&) : strong_count(0), weak_count(0) {} |
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[2bb4a01] | 34 | Node& operator= (const Node&) = delete; |
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| 35 | Node& operator= (Node&&) = delete; |
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[f47f887] | 36 | virtual ~Node() = default; |
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[cedb545] | 37 | |
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[6d51bd7] | 38 | virtual const Node * accept( Visitor & v ) const = 0; |
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[2bb4a01] | 39 | |
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| 40 | /// Types of node references |
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[f47f887] | 41 | enum class ref_type { |
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| 42 | strong, |
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| 43 | weak |
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| 44 | }; |
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[cedb545] | 45 | |
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[87701b6] | 46 | private: |
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| 47 | /// Make a copy of this node; should be overridden in subclass with more precise return type |
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| 48 | virtual Node * clone() const = 0; |
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| 49 | |
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| 50 | /// Must be copied in ALL derived classes |
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| 51 | template<typename node_t> |
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| 52 | friend node_t * mutate(const node_t * node); |
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| 53 | |
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| 54 | mutable size_t strong_count = 0; |
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| 55 | mutable size_t weak_count = 0; |
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| 56 | |
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| 57 | void increment(ref_type ref) const { |
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[f47f887] | 58 | switch (ref) { |
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[6d51bd7] | 59 | case ref_type::strong: strong_count++; break; |
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| 60 | case ref_type::weak : weak_count ++; break; |
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[cedb545] | 61 | } |
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[f47f887] | 62 | } |
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[cedb545] | 63 | |
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[87701b6] | 64 | void decrement(ast::Node::ref_type ref) const { |
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[f47f887] | 65 | switch (ref) { |
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[6d51bd7] | 66 | case ref_type::strong: strong_count--; break; |
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| 67 | case ref_type::weak : weak_count --; break; |
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[cedb545] | 68 | } |
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| 69 | |
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[6d51bd7] | 70 | if(!strong_count && !weak_count) { |
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[f47f887] | 71 | delete this; |
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[6a625de] | 72 | } |
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[f47f887] | 73 | } |
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[6a625de] | 74 | |
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[87701b6] | 75 | template< typename node_t, enum Node::ref_type ref_t > |
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| 76 | friend class ptr_base; |
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[f47f887] | 77 | }; |
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| 78 | |
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| 79 | // Mutate a node, non-member function to avoid static type |
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| 80 | // problems and be able to use auto return |
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| 81 | template<typename node_t> |
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[87701b6] | 82 | node_t * mutate( const node_t * node ) { |
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| 83 | if (node->strong_count <= 1) { |
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[f47f887] | 84 | return const_cast<node_t *>(node); |
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[6a625de] | 85 | } |
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| 86 | |
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[f47f887] | 87 | assertf( |
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| 88 | node->weak_count == 0, |
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| 89 | "Error: mutating node with weak references to it will invalided some references" |
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| 90 | ); |
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| 91 | return node->clone(); |
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| 92 | } |
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| 93 | |
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[54e41b3] | 94 | std::ostream& operator<< ( std::ostream& out, const Node * node ); |
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[2bb4a01] | 95 | |
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[d8938622] | 96 | /// Call a visitor on a possibly-null node |
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| 97 | template<typename node_t> |
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| 98 | auto maybe_accept( const node_t * n, Visitor & v ) -> decltype( n->accept(v) ) { |
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| 99 | return n ? n->accept( v ) : nullptr; |
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| 100 | } |
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| 101 | |
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[9e1d485] | 102 | /// Base class for the smart pointer types |
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| 103 | /// should never really be used. |
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| 104 | template< typename node_t, enum Node::ref_type ref_t > |
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[f47f887] | 105 | class ptr_base { |
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| 106 | public: |
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| 107 | ptr_base() : node(nullptr) {} |
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[87701b6] | 108 | ptr_base( const node_t * n ) : node(n) { if( node ) _inc(node); } |
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| 109 | ~ptr_base() { if( node ) _dec(node); } |
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[f47f887] | 110 | |
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[9e1d485] | 111 | template< enum Node::ref_type o_ref_t > |
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[f47f887] | 112 | ptr_base( const ptr_base<node_t, o_ref_t> & o ) : node(o.node) { |
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[87701b6] | 113 | if( node ) _inc(node); |
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[6a625de] | 114 | } |
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| 115 | |
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[9e1d485] | 116 | template< enum Node::ref_type o_ref_t > |
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[f47f887] | 117 | ptr_base( ptr_base<node_t, o_ref_t> && o ) : node(o.node) { |
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[87701b6] | 118 | if( node ) _inc(node); |
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[6d51bd7] | 119 | } |
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| 120 | |
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| 121 | template<typename o_node_t> |
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| 122 | ptr_base & operator=( const o_node_t * node ) { |
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[8abee136] | 123 | assign( node ? strict_dynamic_cast<const node_t *>(node) : nullptr ); |
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[6d51bd7] | 124 | return *this; |
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[f47f887] | 125 | } |
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[cedb545] | 126 | |
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[9e1d485] | 127 | template< enum Node::ref_type o_ref_t > |
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[f47f887] | 128 | ptr_base & operator=( const ptr_base<node_t, o_ref_t> & o ) { |
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| 129 | assign(o.node); |
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| 130 | return *this; |
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| 131 | } |
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[cedb545] | 132 | |
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[9e1d485] | 133 | template< enum Node::ref_type o_ref_t > |
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[f47f887] | 134 | ptr_base & operator=( ptr_base<node_t, o_ref_t> && o ) { |
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| 135 | assign(o.node); |
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| 136 | return *this; |
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| 137 | } |
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[cedb545] | 138 | |
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[f47f887] | 139 | const node_t * get() const { return node; } |
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| 140 | const node_t * operator->() const { return node; } |
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| 141 | const node_t & operator* () const { return *node; } |
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| 142 | explicit operator bool() const { return node; } |
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[3648d98] | 143 | operator const node_t * () const { return node; } |
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[cedb545] | 144 | |
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[54e41b3] | 145 | /// wrapper for convenient access to dynamic_cast |
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[fdbd4fd] | 146 | template<typename o_node_t> |
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[9e1d485] | 147 | const o_node_t * as() const { return dynamic_cast<const o_node_t *>(node); } |
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[fdbd4fd] | 148 | |
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[76ed81f] | 149 | /// Returns a mutable version of the pointer in this node. |
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| 150 | node_t * get_and_mutate(); |
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| 151 | |
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[54e41b3] | 152 | /// Sets this pointer to a mutated version of a pointer (possibly) owned elsehere. |
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| 153 | /// Returns a mutable version of the pointer in this node. |
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[10a1225] | 154 | node_t * set_and_mutate( const node_t * n ); |
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[54e41b3] | 155 | |
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[f47f887] | 156 | using ptr = const node_t *; |
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[cedb545] | 157 | |
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[f47f887] | 158 | private: |
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[9e1d485] | 159 | void assign( const node_t * other ) { |
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[87701b6] | 160 | if( other ) _inc(other); |
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| 161 | if( node ) _dec(node ); |
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[f47f887] | 162 | node = other; |
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| 163 | } |
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[cedb545] | 164 | |
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[87701b6] | 165 | void _inc( const node_t * other ); |
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| 166 | void _dec( const node_t * other ); |
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| 167 | |
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[f47f887] | 168 | protected: |
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[9e1d485] | 169 | const node_t * node; |
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[f47f887] | 170 | }; |
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[cedb545] | 171 | |
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[2bb4a01] | 172 | /// Owning pointer to node |
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[f47f887] | 173 | template< typename node_t > |
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| 174 | using ptr = ptr_base< node_t, Node::ref_type::strong >; |
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[cedb545] | 175 | |
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[2bb4a01] | 176 | /// Observing pointer to node |
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[f47f887] | 177 | template< typename node_t > |
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| 178 | using readonly = ptr_base< node_t, Node::ref_type::weak >; |
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[2bb4a01] | 179 | } |
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| 180 | |
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| 181 | // Local Variables: // |
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| 182 | // tab-width: 4 // |
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| 183 | // mode: c++ // |
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| 184 | // compile-command: "make install" // |
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[1e97287] | 185 | // End: // |
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