1 /* 2 * Copyright (c) Facebook, Inc. and its affiliates. 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #pragma once 18 19 #include <memory> 20 #include <vector> 21 22 #include <thrift/compiler/ast/t_const.h> 23 #include <thrift/compiler/ast/t_enum.h> 24 #include <thrift/compiler/ast/t_field.h> 25 #include <thrift/compiler/ast/t_program.h> 26 #include <thrift/compiler/ast/t_service.h> 27 #include <thrift/compiler/ast/t_struct.h> 28 29 namespace apache { 30 namespace thrift { 31 namespace compiler { 32 33 // TODO(afuller): Replace usage with ast_visitor and remove. 34 class visitor { 35 public: 36 virtual ~visitor() = default; 37 38 /*** 39 * The entry point for traversal. Call-sites should call this method. 40 */ 41 void traverse(t_program* program); 42 43 /*** 44 * Derived visitor types will generally override these virtual methods. 45 * 46 * Return whether or not to visit children AST nodes afterward. For example, 47 * if `visit(t_program*)` returns `true`, then the visitor will 48 * continue visiting the program's members. 49 * 50 * The default implementations of these virtual methods is simply to return 51 * `true`. This allows derived visitor types to implement only the particular 52 * overloads that they specifically need. 53 * 54 * Note: These are extension points, not entry points for traversal. 55 */ 56 virtual bool visit(t_program* program); 57 virtual bool visit(t_service* service); 58 virtual bool visit(t_enum* tenum); 59 virtual bool visit(t_struct* tstruct); 60 virtual bool visit(t_field* tfield); 61 virtual bool visit(t_const* tconst); 62 63 protected: 64 visitor() = default; 65 66 /*** 67 * Visitor combinator types will generally override these virutal methods. 68 * 69 * General derived visitors should not need to. 70 */ 71 virtual void visit_and_recurse(t_program* program); 72 virtual void visit_and_recurse(t_service* service); 73 virtual void visit_and_recurse(t_enum* tenum); 74 virtual void visit_and_recurse(t_struct* tstruct); 75 virtual void visit_and_recurse(t_field* tfield); 76 virtual void visit_and_recurse(t_const* tconst); 77 78 void recurse(t_program* program); 79 void recurse(t_service* service); 80 void recurse(t_enum* tenum); 81 void recurse(t_struct* tstruct); 82 void recurse(t_field* tfield); 83 void recurse(t_const* tconst); 84 }; 85 86 /*** 87 * Useful for splitting up a single large visitor into multiple smaller ones, 88 * each doing its own portion of the work. 89 * 90 * Runs the visitors across the AST nodes in lockstep with each other, taking 91 * care to recurse with only those visitors which return true from visit(). 92 * 93 * Performs a single concurrent traversal will all visitors, rather than a 94 * sequence of traversals with one visitor each. The concurrent traversal will 95 * interleave all the visitor traversals in lockstep. 96 */ 97 class interleaved_visitor : public visitor { 98 public: 99 explicit interleaved_visitor(std::vector<visitor*> visitors); 100 101 protected: 102 void visit_and_recurse(t_program* program) override; 103 void visit_and_recurse(t_service* service) override; 104 void visit_and_recurse(t_enum* tenum) override; 105 void visit_and_recurse(t_struct* tstruct) override; 106 void visit_and_recurse(t_field* tfield) override; 107 void visit_and_recurse(t_const* tconst) override; 108 109 private: 110 template <typename Visitee> 111 void visit_and_recurse_gen(Visitee* visitee); 112 113 std::vector<visitor*> visitors_; 114 std::vector<bool> rec_mask_{std::vector<bool>(visitors_.size(), true)}; 115 }; 116 117 } // namespace compiler 118 } // namespace thrift 119 } // namespace apache 120