[gnome-2048] Various code improvements.

[Arnaud B. <arnaudb src gnome org>]

commit 80adb04800386cc0b96d5f80231c5ae8fce732c7
Author: Arnaud Bonatti <arnaud bonatti gmail com>
Date:   Fri Feb 1 11:49:27 2019 +0100

    Various code improvements.

 src/game.vala | 29 +++++++++++++++--------------
 src/grid.vala | 44 ++++++++++++++++----------------------------
 2 files changed, 31 insertions(+), 42 deletions(-)
---
diff --git a/src/game.vala b/src/game.vala
index 7ea6bbc..ba300e1 100644
--- a/src/game.vala
+++ b/src/game.vala
@@ -72,11 +72,10 @@ private class Game : Object
 
         int rows = _settings.get_int ("rows");
         int cols = _settings.get_int ("cols");
-        _grid = new Grid (rows, cols);
 
-        _animations_duration = (int)_settings.get_double ("animations-speed");
+        _init_grid (rows, cols, out _grid, ref _settings);
 
-        _settings.bind ("target-value", _grid, "target-value", GLib.SettingsBindFlags.DEFAULT);
+        _animations_duration = (int)_settings.get_double ("animations-speed");
 
         _allow_undo = _settings.get_boolean ("allow-undo");
         _undo_stack_max_size = _settings.get_uint ("allow-undo-max");
@@ -86,6 +85,12 @@ private class Game : Object
         _state = GameState.STOPPED;
     }
 
+    private static void _init_grid (int rows, int cols, out Grid grid, ref GLib.Settings settings)
+    {
+        grid = new Grid (rows, cols);
+        settings.bind ("target-value", grid, "target-value", GLib.SettingsBindFlags.DEFAULT | 
GLib.SettingsBindFlags.NO_SENSITIVITY);
+    }
+
     /*\
     * * view
     \*/
@@ -231,7 +236,7 @@ private class Game : Object
             _clear_foreground ();
             _clear_background ();
 
-            _grid = new Grid (rows, cols);
+            _init_grid (rows, cols, out _grid, ref _settings);
 
             _init_background ();
 
@@ -340,16 +345,14 @@ private class Game : Object
     private void _create_random_tile ()
     {
         Tile tile;
+        _grid.new_tile (out tile);
 
-        if (_grid.new_tile (out tile))
-        {
-            _create_show_hide_transition (true);
+        _create_show_hide_transition (true);
 
-            _create_tile (tile);
-            _to_show.add (tile);
-            _show_tile (tile.pos);
-            _show_hide_trans.start ();
-        }
+        _create_tile (tile);
+        _to_show.add (tile);
+        _show_tile (tile.pos);
+        _show_hide_trans.start ();
     }
 
     private void _create_tile (Tile tile)
@@ -547,8 +550,6 @@ private class Game : Object
 
         _move_trans.remove_all ();
 
-        _create_show_hide_transition (true);
-
         foreach (TileMovement? e in _to_hide)
         {
             if (e == null)
diff --git a/src/grid.vala b/src/grid.vala
index a5ceada..80bf505 100644
--- a/src/grid.vala
+++ b/src/grid.vala
@@ -55,29 +55,24 @@ private class Grid : Object
                 _grid [i, j] = 0;
     }
 
-    internal bool new_tile (out Tile tile)
+    internal void new_tile (out Tile tile)
     {
-        GridPosition pos = { 0, 0 };
-        uint val;
-        tile = { pos, 0 };
-
         if (_grid_is_full ())
-            return false;
+            assert_not_reached ();
 
-        val = 2;
-
-        while (true)
-        {
-            pos = _random_position ();
+        GridPosition pos = { 0, 0 }; // TODO report bug: garbage init needed
+        do { _generate_random_position (rows, cols, out pos); }
+        while (_grid [pos.row, pos.col] != 0);
 
-            if (_grid[pos.row,pos.col] == 0)
-            {
-                _grid[pos.row,pos.col] = val;
-                _check_target_value_reached (val);
-                tile = { pos, val };
-                return true;
-            }
-        }
+        _grid [pos.row, pos.col] = 2;
+        tile = { pos, /* tile value */ 2 };
+    }
+    private static inline void _generate_random_position (int rows, int cols, out GridPosition pos)
+        requires (rows > 0)
+        requires (cols > 0)
+    {
+        pos = { Random.int_range (0, rows),
+                Random.int_range (0, cols) };
     }
 
     internal inline void move (MoveRequest request,
@@ -542,17 +537,10 @@ private class Grid : Object
         return true;
     }
 
-    private GridPosition _random_position ()
-    {
-        GridPosition ret = { Random.int_range (0, (int)_rows),
-                             Random.int_range (0, (int)_cols) };
-
-        return ret;
-    }
-
     private void _check_target_value_reached (uint val)
+        requires (target_value > 3)
     {
-        if (target_value != 0 && val == target_value)
+        if ( val == target_value)
             target_value_reached = true;
     }
 }