src/driver.h

   1 /* $Id: driver.h 26108 2013-11-25 14:30:22Z rubidium $ */
   2
   3 /*
   4  * This file is part of OpenTTD.
   5  * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
   6  * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
   7  * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
   8  */
   9
  10 /** @file driver.h Base for all drivers (video, sound, music, etc). */
  11
  12 #ifndef DRIVER_H
  13 #define DRIVER_H
  14
  15 #include "core/enum_type.hpp"
  16 #include "core/string_compare_type.hpp"
  17 #include <map>
  18
  19 const char *GetDriverParam(const char * const *parm, const char *name);
  20 bool GetDriverParamBool(const char * const *parm, const char *name);
  21 int GetDriverParamInt(const char * const *parm, const char *name, int def);
  22
  23 /** A driver for communicating with the user. */
  24 class Driver {
  25 public:
  26         /**
  27          * Start this driver.
  28          * @param parm Parameters passed to the driver.
  29          * @return nullptr if everything went okay, otherwise an error message.
  30          */
  31         virtual const char *Start(const char * const *parm) = 0;
  32
  33         /**
  34          * Stop this driver.
  35          */
  36         virtual void Stop() = 0;
  37
  38         virtual ~Driver() { }
  39
  40         /** The type of driver */
  41         enum Type {
  42                 DT_BEGIN = 0, ///< Helper for iteration
  43                 DT_MUSIC = 0, ///< A music driver, needs to be before sound to properly shut down extmidi forked music players
  44                 DT_SOUND,     ///< A sound driver
  45                 DT_VIDEO,     ///< A video driver
  46                 DT_END,       ///< Helper for iteration
  47         };
  48
  49         /**
  50          * Get the name of this driver.
  51          * @return The name of the driver.
  52          */
  53         virtual const char *GetName() const = 0;
  54 };
  55
  56 DECLARE_POSTFIX_INCREMENT(Driver::Type)
  57
  58
  59 /** Base for all driver factories. */
  60 class DriverFactoryBase {
  61 private:
  62         friend class MusicDriver;
  63         friend class SoundDriver;
  64         friend class VideoDriver;
  65
  66         Driver::Type type;       ///< The type of driver.
  67         int priority;            ///< The priority of this factory.
  68         const char *name;        ///< The name of the drivers of this factory.
  69         const char *description; ///< The description of this driver.
  70
  71         typedef std::map<const char *, DriverFactoryBase *, StringCompare> Drivers; ///< Type for a map of drivers.
  72
  73         /**
  74          * Get the map with drivers.
  75          */
  76         static Drivers &GetDrivers()
  77         {
  78                 static Drivers &s_drivers = *new Drivers();
  79                 return s_drivers;
  80         }
  81
  82         /**
  83          * Get the active driver for the given type.
  84          * @param type The type to get the driver for.
  85          * @return The active driver.
  86          */
  87         static Driver **GetActiveDriver(Driver::Type type)
  88         {
  89                 static Driver *s_driver[3] = { nullptr, nullptr, nullptr };
  90                 return &s_driver[type];
  91         }
  92
  93         /**
  94          * Get the driver type name.
  95          * @param type The type of driver to get the name of.
  96          * @return The name of the type.
  97          */
  98         static const char *GetDriverTypeName(Driver::Type type)
  99         {
 100                 static const char * const driver_type_name[] = { "music", "sound", "video" };
 101                 return driver_type_name[type];
 102         }
 103
 104         static bool SelectDriverImpl(const char *name, Driver::Type type);
 105
 106 protected:
 107         DriverFactoryBase(Driver::Type type, int priority, const char *name, const char *description);
 108
 109         virtual ~DriverFactoryBase();
 110
 111 public:
 112         /**
 113          * Shuts down all active drivers
 114          */
 115         static void ShutdownDrivers()
 116         {
 117                 for (Driver::Type dt = Driver::DT_BEGIN; dt < Driver::DT_END; dt++) {
 118                         Driver *driver = *GetActiveDriver(dt);
 119                         if (driver != nullptr) driver->Stop();
 120                 }
 121         }
 122
 123         static void SelectDriver(const char *name, Driver::Type type);
 124         static char *GetDriversInfo(char *p, const char *last);
 125
 126         /**
 127          * Get a nice description of the driver-class.
 128          * @return The description.
 129          */
 130         const char *GetDescription() const
 131         {
 132                 return this->description;
 133         }
 134
 135         /**
 136          * Create an instance of this driver-class.
 137          * @return The instance.
 138          */
 139         virtual Driver *CreateInstance() const = 0;
 140 };
 141
 142 #endif /* DRIVER_H */