qt: allow user to choose data directory

This adds an introduction screen that is shown when the client is first
started in which the user can choose a data directory.

It is also possible to force the intro screen to appear using command
line argument `-choosedatadir`.

The user is warned that the client will download and store 10Gb of data.
The intro screen shows how much space is available on the device that
contains the chosen directory and warns if this is less than the 10Gb.

To make it possible to translate the introduction dialog, the initialization
sequence is changed so that translations are
loaded before the data directory. This has the by-effect that it is
no longer possible to specify a language in bitcoin.conf inside the data
directory.

1 files changed, 67 insertions, 0 deletions

diff --git a/src/qt/intro.h b/src/qt/intro.h
new file mode 100644
index 0000000000..b246c65a82
--- /dev/null
+++ b/src/qt/intro.h
@@ -0,0 +1,67 @@
+#ifndef INTRO_H
+#define INTRO_H
+
+#include <QDialog>
+#include <QThread>
+#include <QMutex>
+
+namespace Ui {
+class Intro;
+}
+class FreespaceChecker;
+
+/** Introduction screen (pre-GUI startup).
+  Allows the user to choose a data directory,
+  in which the wallet and block chain will be stored.
+ */
+class Intro : public QDialog
+{
+    Q_OBJECT
+
+public:
+    explicit Intro(QWidget *parent = 0);
+    ~Intro();
+
+    QString getDataDirectory();
+    void setDataDirectory(const QString &dataDir);
+
+    /**
+     * Determine data directory. Let the user choose if the current one doesn't exist.
+     *
+     * @note do NOT call global GetDataDir() before calling this function, this
+     * will cause the wrong path to be cached.
+     */
+    static void pickDataDirectory();
+
+    /**
+     * Determine default data directory for operating system.
+     */
+    static QString getDefaultDataDirectory();
+signals:
+    void requestCheck();
+    void stopThread();
+
+public slots:
+    void setStatus(int status, const QString &message, quint64 bytesAvailable);
+
+private slots:
+    void on_dataDirectory_textChanged(const QString &arg1);
+    void on_ellipsisButton_clicked();
+    void on_dataDirDefault_clicked();
+    void on_dataDirCustom_clicked();
+
+private:
+    Ui::Intro *ui;
+    QThread *thread;
+    QMutex mutex;
+    bool signalled;
+    QString pathToCheck;
+
+    void startThread();
+    void checkPath(const QString &dataDir);
+    QString getPathToCheck();
+
+    friend class FreespaceChecker;
+};
+
+#endif // INTRO_H