Add unlockable icon

include/ui/unlockableicon.h

@@ -0,0 +1,57 @@
+#ifndef UNLOCKABLEICON_H
+#define UNLOCKABLEICON_H
+
+// Manages an icon loaded from an obfuscated data file containing the icon's image data and a key.
+// The icon can only be accessed by inputting the correct key.
+
+#include <QObject>
+#include <QIcon>
+#include <QString>
+#include <QSet>
+
+class UnlockableIcon : public QObject
+{
+    Q_OBJECT
+public:
+    UnlockableIcon(QObject* parent = nullptr);
+    UnlockableIcon(const QString& dataFilepath, QObject* parent = nullptr);
+    ~UnlockableIcon() {};
+
+    // Create the obfuscated data file to load an unlockable icon from.
+    // Normally unused, this is only needed to update the resource data file.
+    static bool createDataFile(const QString& inputFilepath, const QString& outputFilepath, const QString& key);
+
+    bool load(const QString& dataFilepath);
+    void clear();
+
+    // Try to unlock the icon by matching the next character in the key.
+    // Progress resets if the character is not a match.
+    void tryUnlock(const QChar& c);
+
+    // Try to unlock the icon by matching the next character in the key.
+    // Progress resets if none of the characters in the set are a match.
+    void tryUnlock(const QSet<QChar>& cSet);
+
+    // Try to unlock the icon by matching the remaining characters in the key.
+    // Progress resets if any character in the string is not a match.
+    void tryUnlock(const QString& key);
+
+    bool isUnlocked() const;
+    QIcon icon() const;
+
+signals:
+    void unlocked(const QIcon& icon);
+
+private:
+    QIcon m_icon;
+    QString m_key;
+    quint32 m_keyIndex = 0;
+    bool m_loaded = false;
+
+    bool canUnlock() const;
+    bool tryKeyMatch(const QSet<QChar>& cSet);
+};
+
+
+
+#endif // UNLOCKABLEICON_H