GetFEM  5.4.3
gmm_feedback_management.h
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1 /* -*- c++ -*- (enables emacs c++ mode) */
2 /*===========================================================================
3 
4  Copyright (C) 2002-2020 Yves Renard
5 
6  This file is a part of GetFEM
7 
8  GetFEM is free software; you can redistribute it and/or modify it
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30 ===========================================================================*/
31 
32 /** @file gmm_feedback_management.h
33  @date July 03, 2017.
34  @brief Support for run time management of trace, warning and assert
35  feedback.
36 */
37 
38 #ifndef GMM_FEEDBACK_MANAGEMENT_H__
39 #define GMM_FEEDBACK_MANAGEMENT_H__
40 #include <iostream>
41 #include <string>
42 #include <memory>
43 
44 namespace gmm {
45 
46 /* *********************************************************************** */
47 /* GetFEM warnings. */
48 /* *********************************************************************** */
49 
50 // This allows to dynamically hide warnings
51 struct warning_level {
52  static int level(int l = -2)
53  { static int level_ = 3; return (l != -2) ? (level_ = l) : level_; }
54 };
55 
56 inline void set_warning_level(int l) { warning_level::level(l>0 ? l : 0); }
57 inline int get_warning_level(void) { return warning_level::level(-2); }
58 
59 /* *********************************************************************** */
60 /* GetFEM traces. */
61 /* *********************************************************************** */
62 
63 // This allows to dynamically hide traces
64 struct traces_level {
65  static int level(int l = -2)
66  { static int level_ = 3; return (l != -2) ? (level_ = l) : level_; }
67 };
68 
69 inline void set_traces_level(int l) { traces_level::level(l>0 ? l : 0); }
70 inline int get_traces_level(void) { return traces_level::level(); }
71 
72 
73 /* *********************************************************************** */
74 /* GetFEM feedback management */
75 /* *********************************************************************** */
76 
77 enum class FeedbackType {
78  TRACE = 0,
79  WARNING,
80  ASSERT
81 };
82 
83 // Abstract class providing feedback management interface.
84 // The interface consist of three functions:
85 // * for sending feedback message
86 // * for getting traces level
87 // * for getting warning level
88 // * for action to be done after feedback is handled
89 struct base_feedback_handler {
90  virtual ~base_feedback_handler() = default;
91  virtual void send(const std::string &message, FeedbackType messageType, size_t level) = 0;
92  virtual size_t traces_level() { return get_traces_level(); }
93  virtual size_t warning_level() { return get_warning_level(); }
94  virtual void terminating_action() = 0;
95 };
96 
97 
98 // Provides the default implementation of feedback handling.
99 struct default_feedback_handler final : public base_feedback_handler {
100  void send(const std::string &message, FeedbackType, size_t) override {
101  std::cerr << message << std::endl;
102  }
103  void terminating_action() override {
104  std::exit(1);
105  }
106 };
107 
108 // This class acts as a run-time dispatcher for sending feedback
109 // messages and getting trace and warning levels.
110 class feedback_manager {
111 public:
112  // Management actions
113  enum Action {
114  SET, // Sets the feedback handler, releasing the one previously set.
115  GET, // Returns currently managed handler (it is still managed).
116  REPLACE, // Replace manager with a new one, stop managing the old one
117  // and returns it unmanaged to the caller. The caller is
118  // then responsible for managing the memory of the handler.
119  };
120 
121  // Steals the pointer to a messenger object that provides
122  // feedback handling implementation.
123  //
124  // Example:
125  // feedback_manager::manage(new default_feedback_handler);
126  //
127  static base_feedback_handler* manage(enum Action action=GET, base_feedback_handler *pHandler=nullptr);
128  static void send(const std::string &message, FeedbackType type, size_t level);
129  static size_t traces_level();
130  static size_t warning_level();
131  // Action to be taken when feedback handling is done
132  static void terminating_action();
133 };
134 
135 // Depending on action either gets, sets or replaces feedback handler. Setting handler to null resets
136 // it to gmm::default_feedback_handler.
137 inline base_feedback_handler* feedback_manager::manage(enum Action action, base_feedback_handler *pHandler) {
138  static std::unique_ptr<base_feedback_handler>
139  pHandler_ = std::make_unique<default_feedback_handler>();
140  base_feedback_handler *rethandler = nullptr;
141  switch(action) {
142  case SET:
143  pHandler_.reset(pHandler != nullptr ? pHandler : new default_feedback_handler);
144  rethandler = pHandler_.get();
145  break;
146  case GET:
147  rethandler = pHandler_.get();
148  break;
149  case REPLACE:
150  rethandler = pHandler_.release();
151  pHandler_.reset(pHandler != nullptr ? pHandler : new default_feedback_handler);
152  break;
153  }
154  return rethandler;
155 }
156 
157 inline void feedback_manager::send(const std::string &message, FeedbackType type, size_t level) {
158  feedback_manager::manage()->send(message, type, level);
159 }
160 
161 inline void feedback_manager::terminating_action() {
162  feedback_manager::manage()->terminating_action();
163 }
164 
165 inline size_t feedback_manager::traces_level() {
166  return feedback_manager::manage()->traces_level();
167 }
168 
169 inline size_t feedback_manager::warning_level() {
170  return feedback_manager::manage()->warning_level();
171 }
172 
173 } // namespace gmm
174 #endif /* GMM_FEEDBACK_MANAGEMENT_H__ */