kinetic-scroll-view: Use gint64 for timestamps rather than GTimeVal

GTimeVal is a pain to use and the use of glong means the potential
for overflow when summing several timestamps on 32-bit platforms is
quite high. Instead, use gint64 and g_get_real_time().

clutter-project#98

mx/mx-kinetic-scroll-view.c

@@ -66,7 +66,7 @@ typedef struct {
  /* Units to store the origin of a click when scrolling */
  gfloat x;
  gfloat y;
- GTimeVal time;
+ gint64 time; /* use g_get_real_time() for this */
 } MxKineticScrollViewMotion;
 
 typedef enum {
@@ -758,12 +758,12 @@ add_motion_event (MxKineticScrollView *scroll,
  gfloat y)
 {
  MxKineticScrollViewPrivate *priv = scroll->priv;
- GTimeVal tv;
+ gint64 tv;
 
  LOG_DEBUG (scroll, "%s: x = %f, y = %f, n_motions = %u",
  G_STRFUNC, x, y, priv->n_motions);
 
- g_get_current_time (&tv);
+ tv = g_get_real_time ();
 
  if (priv->n_motions == 0)
  {
@@ -786,8 +786,7 @@ add_motion_event (MxKineticScrollView *scroll,
 
  priv->motion_total.x += x;
  priv->motion_total.y += y;
- priv->motion_total.time.tv_sec += tv.tv_sec;
- priv->motion_total.time.tv_usec += tv.tv_usec;
+ priv->motion_total.time += tv;
 
  /* Avoid overflow by only taking this branch if n_motions will not
  * overflow. Subsequent motions are ignored. */
@@ -1359,37 +1358,28 @@ release_event (MxKineticScrollView *scroll,
  gdouble value, lower, upper, step_increment, page_size,
  d, ax, ay, y, nx, ny, n;
  gfloat frac, x_origin, y_origin;
- GTimeVal release_time, motion_time;
+ gint64 release_time, motion_time; /* real microseconds */
  MxAdjustment *hadjust, *vadjust;
- glong time_diff;
+ gint64 time_diff; /* real microseconds */
  guint duration;
 
  /* Get time delta */
- g_get_current_time (&release_time);
+ release_time = g_get_real_time ();
 
  /* Get average position/time of last x mouse events */
  x_origin = y_origin = 0;
- motion_time = (GTimeVal){ 0, 0 };
+ motion_time = 0;
 
  g_assert (priv->n_motions > 0);
 
  x_origin = priv->motion_total.x / priv->n_motions;
  y_origin = priv->motion_total.y / priv->n_motions;
- motion_time.tv_sec = priv->motion_total.time.tv_sec / priv->n_motions;
- motion_time.tv_usec = priv->motion_total.time.tv_usec / priv->n_motions;
+ motion_time = priv->motion_total.time / priv->n_motions;
 
- /* Normalise the GTimeVal. */
- motion_time.tv_sec += motion_time.tv_usec / G_USEC_PER_SEC;
- motion_time.tv_usec %= G_USEC_PER_SEC;
-
- if (motion_time.tv_sec == release_time.tv_sec)
- time_diff = release_time.tv_usec - motion_time.tv_usec;
- else
- time_diff = release_time.tv_usec +
- (G_USEC_PER_SEC - motion_time.tv_usec);
+ time_diff = release_time - motion_time;
 
  /* Work out the fraction of 1/60th of a second that has elapsed */
- frac = (time_diff/1000.0) / (1000.0/60.0);
+ frac = (time_diff / 1000.0) / (1000.0 / 60.0);
 
  /* See how many units to move in 1/60th of a second */
  priv->dx = (x_origin - event_x) / frac * priv->acceleration_factor;
@@ -1421,7 +1411,7 @@ release_event (MxKineticScrollView *scroll,
  LOG_DEBUG (scroll, "%s: checking duration: x_pos = %i, y_pos = %i, "
  "event_x = %f, event_y = %f, y = %f, nx = %f, ny = %f, "
  "n = %f, frac = %f, x_origin = %f, y_origin = %f, "
- "time_diff = %lu, duration = %u, "
+ "time_diff = %" G_GINT64_FORMAT ", duration = %u, "
  "priv->n_motions = %u, priv->dx = %f, "
  "priv->dy = %f, priv->decel_rate = %f, "
  "priv->overshoot = %f, priv->accumulated_delta = %f, "
@@ -1538,7 +1528,7 @@ release_event (MxKineticScrollView *scroll,
  "upper = %f, step_increment = %f, page_size = %f, "
  "d = %f, ax = %f, ay = %f, y = %f, nx = %f, ny = %f, "
  "n = %f, frac = %f, x_origin = %f, y_origin = %f, "
- "time_diff = %lu, duration = %u, "
+ "time_diff = %" G_GINT64_FORMAT ", duration = %u, "
  "priv->n_motions = %u, priv->dx = %f, "
  "priv->dy = %f, priv->decel_rate = %f, "
  "priv->overshoot = %f, priv->accumulated_delta = %f, "