src/Device/SettingsMap.hpp

   1 /*
   2 Copyright_License {
   3
   4   XCSoar Glide Computer - http://www.xcsoar.org/
   5   Copyright (C) 2000-2013 The XCSoar Project
   6   A detailed list of copyright holders can be found in the file "AUTHORS".
   7
   8   This program is free software; you can redistribute it and/or
   9   modify it under the terms of the GNU General Public License
  10   as published by the Free Software Foundation; either version 2
  11   of the License, or (at your option) any later version.
  12
  13   This program is distributed in the hope that it will be useful,
  14   but WITHOUT ANY WARRANTY; without even the implied warranty of
  15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16   GNU General Public License for more details.
  17
  18   You should have received a copy of the GNU General Public License
  19   along with this program; if not, write to the Free Software
  20   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  21 }
  22 */
  23
  24 #ifndef XCSOAR_DEVICE_SETTINGS_MAP_HPP
  25 #define XCSOAR_DEVICE_SETTINGS_MAP_HPP
  26
  27 #include "Util/Serial.hpp"
  28 #include "Time/TimeoutClock.hpp"
  29 #include "Thread/Mutex.hpp"
  30 #include "Operation/Operation.hpp"
  31
  32 #ifdef HAVE_POSIX
  33 #include "Thread/Cond.hpp"
  34 #else
  35 #include "OS/Sleep.h"
  36 #endif
  37
  38 #include <map>
  39 #include <string>
  40 #include <algorithm>
  41
  42 /**
  43  * A thread-safe store for named values received from a device.  The
  44  * driver's NMEA parser fills values, and another thread may wait for
  45  * this.
  46  *
  47  * The caller is responsible for locking and unlocking an instance for
  48  * each method call.
  49  */
  50 template<typename V>
  51 class DeviceSettingsMap {
  52   Mutex mutex;
  53 #ifdef HAVE_POSIX
  54   Cond cond;
  55 #endif
  56
  57   struct Item {
  58     V value;
  59
  60     bool old;
  61
  62     explicit Item(const V &_value):value(_value) {}
  63   };
  64
  65   typedef std::map<std::string, Item> Map;
  66
  67   Map map;
  68
  69 public:
  70   class const_iterator {
  71     typename Map::const_iterator i;
  72
  73   public:
  74     explicit const_iterator(typename Map::const_iterator _i):i(_i) {}
  75
  76     const V &operator*() const {
  77       return i->second.value;
  78     }
  79
  80     const V *operator->() const {
  81       return &i->second.value;
  82     }
  83
  84     bool operator==(const const_iterator &other) const {
  85       return i == other.i;
  86     }
  87
  88     bool operator!=(const const_iterator &other) const {
  89       return i != other.i;
  90     }
  91   };
  92
  93   void Lock() {
  94     mutex.Lock();
  95   }
  96
  97   void Unlock() {
  98     mutex.Unlock();
  99   }
 100
 101   operator Mutex &() const {
 102     return const_cast<Mutex &>(mutex);
 103   }
 104
 105   template<typename K>
 106   void MarkOld(const K &key) {
 107     auto i = map.find(key);
 108     if (i != map.end())
 109       i->second.old = true;
 110   }
 111
 112   template<typename K>
 113   const_iterator Wait(const K &key, OperationEnvironment &env,
 114                       TimeoutClock &timeout) {
 115     while (true) {
 116       auto i = map.find(key);
 117       if (i != map.end() && !i->second.old)
 118         return const_iterator(i);
 119
 120       if (env.IsCancelled())
 121         return end();
 122
 123       int remaining = timeout.GetRemainingSigned();
 124       if (remaining <= 0)
 125         return end();
 126
 127 #ifdef HAVE_POSIX
 128       cond.Wait(*this, remaining);
 129 #else
 130       /* Windows doesn't have condition objects, sorry for this ugly
 131          kludge :-( */
 132       Sleep(std::min(remaining, 250));
 133 #endif
 134     }
 135   }
 136
 137   template<typename K>
 138   const_iterator Wait(const K &key, OperationEnvironment &env,
 139                       unsigned timeout_ms) {
 140     TimeoutClock timeout(timeout_ms);
 141     return Wait(key, env, timeout);
 142   }
 143
 144   template<typename K>
 145   gcc_pure
 146   const_iterator find(const K &key) const {
 147     return const_iterator(map.find(key));
 148   }
 149
 150   gcc_pure
 151   const_iterator end() const {
 152     return const_iterator(map.end());
 153   }
 154
 155   template<typename K>
 156   void Set(const K &key, const V &value) {
 157     auto i = map.insert(std::make_pair(key, Item(value)));
 158     Item &item = i.first->second;
 159     item.old = false;
 160     if (!i.second)
 161       item.value = value;
 162
 163 #ifdef HAVE_POSIX
 164     cond.Broadcast();
 165 #endif
 166   }
 167
 168   template<typename K>
 169   void erase(const K &key) {
 170     map.erase(key);
 171   }
 172
 173   void clear() {
 174     map.clear();
 175   }
 176 };
 177
 178 #endif