LPreferences.h

   1 // key/value user settings service
   2 // Copyright © 2009 The University of Chicago
   3 #ifndef LPREFERENCES_H
   4 #define LPREFERENCES_H
   5
   6 class CLPreferences;
   7
   8 #include <map>
   9 #include <QString>
  10 template<class K, class V> class QMap;
  11
  12 /// A CLPreferences object maintains a list of key/value pairs
  13 /// representing parameters for Linguistica’s various algorithms.
  14 ///
  15 /// Settings can be read from and written to a QSettings object
  16 /// (for transparently remembering their values in the Windows
  17 /// registry or a dotfile in the user’s home directory), a
  18 /// named file (for importing or exporting preferences to share
  19 /// them), or both.
  20 ///
  21 /// Settings are read on construction and written on destruction
  22 /// of the preferences object.  One can also explicitly request
  23 /// a read or write of preferences using the LoadPrefs or
  24 /// StorePrefs method.
  25 ///
  26 /// The values of all parameters can be saved into memory and
  27 /// restored using the data() method.  Example:
  28 ///
  29 ///     QSettings settings
  30 ///     CLPreferences prefs(&settings);
  31 ///     // Unless do_something_to() calls StorePrefs(), the
  32 ///     // following block has no effect on prefs.
  33 ///     {
  34 ///             CLPreferences::data_type saved = prefs.data();
  35 ///             do_something_to(prefs);
  36 ///             // oops! back that out:
  37 ///             prefs.data() = saved;
  38 ///     }
  39 class CLPreferences {
  40 public:
  41         typedef std::map<QString, QString> data_type;
  42 private:
  43         // where to read/write settings for long-term storage
  44         /// pointer to a handle for a Windows Registry-style
  45         /// setting storage service.  Unused if null.
  46         class QSettings* registry;
  47         /// filename for an “exported settings” file to use.
  48         /// Unused if empty.
  49         QString prefs_filename;
  50
  51         // Linguistica parameters
  52         data_type m;
  53 public:
  54         // construction/destruction.
  55
  56         /// preferences stored in *settings
  57         explicit CLPreferences(QSettings* settings);
  58         /// preferences stored in named file
  59         explicit CLPreferences(QString filename);
  60         /// save preferences to long-term storage
  61         ~CLPreferences();
  62 private:
  63         // disable default-construction and copy.
  64         CLPreferences();
  65         CLPreferences(const CLPreferences& x);
  66         CLPreferences& operator=(const CLPreferences& x);
  67 public:
  68
  69         // string preference values.
  70
  71         QString GetPreference(QString key) const;
  72         void SetPreference(QString key, QString value);
  73         void RemovePreference(QString key);
  74
  75         // integer preference values.
  76
  77         /// result is -1 on error
  78         int GetIntPreference(QString key) const;
  79         void SetIntPreference(QString key, int value);
  80         void RemoveIntPreference(QString key) { RemovePreference(key); }
  81
  82         // font preference values.
  83
  84         class QFont GetFontPreference(QString key) const;
  85         void SetFontPreference(QString key, class QFont value);
  86         void RemoveFontPreference(QString key);
  87
  88         // StringList preference values.
  89
  90         void GetStringListPreference(QString key,
  91                 class QStringList* out) const;
  92         void SetStringListPreference(QString key,
  93                 const class QStringList& value);
  94
  95         // dictionary preference values.
  96
  97         void GetDictionaryPreference(QString key,
  98                 QMap<QString, QString>* out) const;
  99         /// requires: no key in val.keys() contains a colon
 100         void SetDictionaryPreference(QString key,
 101                 const QMap<QString, QString>& val);
 102
 103         // mass storage and retrieval.
 104
 105         void LoadPrefs();
 106         void StorePrefs() const;
 107
 108         // export to file.
 109
 110         void load_prefs_from_file(const QString& filename);
 111         /// requires: no key in m contains an equal sign
 112         void store_prefs_to_file(const QString& filename) const;
 113
 114         // save/restore preference data.
 115
 116         data_type& data() { return m; }
 117         const data_type& data() const { return m; }
 118 };
 119
 120 #endif // LPREFERENCES_H