[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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| 11 | // Last Modified By : Aaron B. Moss |
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| 12 | // Last Modified On : Wed May 8 11:00:00 2019 |
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| 13 | // Update Count : 2 |
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| 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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| 32 | Node(const Node&) : strong_ref(0), weak_ref(0) {} |
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| 33 | Node(Node&&) : strong_ref(0), weak_ref(0) {} |
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| 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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[2bb4a01] | 38 | virtual Node* accept( Visitor& v ) = 0; |
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| 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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[f47f887] | 46 | inline void increment(ref_type ref) const { |
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| 47 | switch (ref) { |
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| 48 | case ref_type::strong: strong_ref++; break; |
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| 49 | case ref_type::weak : weak_ref ++; break; |
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[cedb545] | 50 | } |
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[f47f887] | 51 | } |
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[cedb545] | 52 | |
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[f47f887] | 53 | inline void decrement(ref_type ref) const { |
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| 54 | switch (ref) { |
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| 55 | case ref_type::strong: strong_ref--; break; |
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| 56 | case ref_type::weak : weak_ref --; break; |
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[cedb545] | 57 | } |
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| 58 | |
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[f47f887] | 59 | if(!strong_ref && !weak_ref) { |
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| 60 | delete this; |
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[6a625de] | 61 | } |
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[f47f887] | 62 | } |
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[6a625de] | 63 | |
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[f47f887] | 64 | template<typename node_t> |
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| 65 | friend auto mutate(const node_t * node); |
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| 66 | |
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| 67 | private: |
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[2bb4a01] | 68 | /// Make a copy of this node; should be overridden in subclass with more precise return type |
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| 69 | virtual Node* clone() const = 0; |
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| 70 | |
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[f47f887] | 71 | mutable size_t strong_ref = 0; |
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| 72 | mutable size_t weak_ref = 0; |
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| 73 | }; |
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| 74 | |
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| 75 | // Mutate a node, non-member function to avoid static type |
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| 76 | // problems and be able to use auto return |
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| 77 | template<typename node_t> |
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| 78 | auto mutate(const node_t * node) { |
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| 79 | assertf( |
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| 80 | node->strong_count >= 1, |
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| 81 | "Error: attempting to mutate a node that appears to have been linked" |
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| 82 | ); |
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| 83 | if (node->strong_count == 1) { |
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| 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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[2bb4a01] | 94 | std::ostream& operator<< ( std::ostream& out, const Node* node ); |
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| 95 | |
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[9e1d485] | 96 | /// Base class for the smart pointer types |
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| 97 | /// should never really be used. |
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| 98 | template< typename node_t, enum Node::ref_type ref_t > |
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[f47f887] | 99 | class ptr_base { |
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| 100 | public: |
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| 101 | ptr_base() : node(nullptr) {} |
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[9e1d485] | 102 | ptr_base( const node_t * n ) : node(n) { if( node ) node->increment(ref_t); } |
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[f47f887] | 103 | ~ptr_base() { if( node ) node->decrement(ref_t); } |
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| 104 | |
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[9e1d485] | 105 | template< enum Node::ref_type o_ref_t > |
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[f47f887] | 106 | ptr_base( const ptr_base<node_t, o_ref_t> & o ) : node(o.node) { |
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[9e1d485] | 107 | if( node ) node->increment(ref_t); |
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[6a625de] | 108 | } |
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| 109 | |
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[9e1d485] | 110 | template< enum Node::ref_type o_ref_t > |
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[f47f887] | 111 | ptr_base( ptr_base<node_t, o_ref_t> && o ) : node(o.node) { |
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| 112 | if( node ) node->increment(ref_t); |
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| 113 | } |
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[cedb545] | 114 | |
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[9e1d485] | 115 | template< enum Node::ref_type o_ref_t > |
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[f47f887] | 116 | ptr_base & operator=( const ptr_base<node_t, o_ref_t> & o ) { |
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| 117 | assign(o.node); |
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| 118 | return *this; |
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| 119 | } |
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[cedb545] | 120 | |
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[9e1d485] | 121 | template< enum Node::ref_type o_ref_t > |
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[f47f887] | 122 | ptr_base & operator=( ptr_base<node_t, o_ref_t> && o ) { |
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| 123 | assign(o.node); |
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| 124 | return *this; |
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| 125 | } |
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[cedb545] | 126 | |
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[f47f887] | 127 | const node_t * get() const { return node; } |
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| 128 | const node_t * operator->() const { return node; } |
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| 129 | const node_t & operator* () const { return *node; } |
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| 130 | explicit operator bool() const { return node; } |
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| 131 | operator const node_t * const() const { return node; } |
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[cedb545] | 132 | |
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[fdbd4fd] | 133 | template<typename o_node_t> |
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[9e1d485] | 134 | const o_node_t * as() const { return dynamic_cast<const o_node_t *>(node); } |
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[fdbd4fd] | 135 | |
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[f47f887] | 136 | using ptr = const node_t *; |
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[cedb545] | 137 | |
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[f47f887] | 138 | private: |
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[9e1d485] | 139 | void assign( const node_t * other ) { |
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[f47f887] | 140 | if( other ) other->increment(ref_t); |
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| 141 | if( node ) node ->decrement(ref_t); |
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| 142 | node = other; |
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| 143 | } |
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[cedb545] | 144 | |
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[f47f887] | 145 | protected: |
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[9e1d485] | 146 | const node_t * node; |
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[f47f887] | 147 | }; |
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[cedb545] | 148 | |
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[2bb4a01] | 149 | /// Owning pointer to node |
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[f47f887] | 150 | template< typename node_t > |
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| 151 | using ptr = ptr_base< node_t, Node::ref_type::strong >; |
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[cedb545] | 152 | |
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[2bb4a01] | 153 | /// Observing pointer to node |
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[f47f887] | 154 | template< typename node_t > |
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| 155 | using readonly = ptr_base< node_t, Node::ref_type::weak >; |
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[2bb4a01] | 156 | } |
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| 157 | |
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| 158 | // Local Variables: // |
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| 159 | // tab-width: 4 // |
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| 160 | // mode: c++ // |
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| 161 | // compile-command: "make install" // |
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| 162 | // End: // |
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