[PATCH] Fix crash on right click dive trip.

[amit.k.chaudhuri at gmail.com]

From: Amit Chaudhuri <amit.k.chaudhuri at gmail.com>

A null pointer dereference occured after right click on a dive trip
because updateDiveInfo was called with dive == -1 causing get_dive(int)
to return null.

Wrap to avoid crash and clear dive info widget text labels.

Signed-off-by: Amit Chaudhuri <amit.k.chaudhuri at gmail.com>
---
 qt-ui/maintab.cpp |   28 +++++++++++++++++++++-------
 1 file changed, 21 insertions(+), 7 deletions(-)

diff --git a/qt-ui/maintab.cpp b/qt-ui/maintab.cpp
index 89501fc..3734aba 100644
--- a/qt-ui/maintab.cpp
+++ b/qt-ui/maintab.cpp
@@ -91,13 +91,27 @@ void MainTab::updateDiveInfo(int dive)
 		ui->rating->setCurrentStars(d->rating);
 	else
 		ui->rating->setCurrentStars(0);
-	ui->maximumDepthText->setText(get_depth_string(d->maxdepth, TRUE));
-	ui->averageDepthText->setText(get_depth_string(d->meandepth, TRUE));
-	sacVal.mliter = d ? d->sac : 0;
-	ui->sacText->setText(get_volume_string(sacVal, TRUE).append("/min"));
-	ui->otuText->setText(QString("%1").arg( d ? d->otu : 0));
-	ui->waterTemperatureText->setText(d ? get_temperature_string(d->watertemp, TRUE) : "");
-	ui->airTemperatureText->setText(d ? get_temperature_string(d->airtemp, TRUE) : "");
+	if (d) {
+		ui->maximumDepthText->setText(get_depth_string(d->maxdepth, TRUE));
+		ui->averageDepthText->setText(get_depth_string(d->meandepth, TRUE));
+		sacVal.mliter = d ? d->sac : 0;
+		ui->sacText->setText(get_volume_string(sacVal, TRUE).append("/min"));
+		ui->otuText->setText(QString("%1").arg( d ? d->otu : 0));
+		ui->waterTemperatureText->setText(d ? get_temperature_string(d->watertemp, TRUE) : "");
+		ui->airTemperatureText->setText(d ? get_temperature_string(d->airtemp, TRUE) : "");
+	} else {
+		ui->sacText->setText(QString());
+		ui->otuText->setText(QString());
+		ui->oxygenHeliumText->setText(QString());
+		ui->dateText->setText(QString());
+		ui->diveTimeText->setText(QString());
+		ui->surfaceIntervalText->setText(QString());
+		ui->maximumDepthText->setText(QString());
+		ui->averageDepthText->setText(QString());
+		ui->visibilityText->setText(QString());
+		ui->waterTemperatureText->setText(QString());
+		ui->airTemperatureText->setText(QString());
+	}
 	if (d && d->surface_pressure.mbar)
 		/* this is ALWAYS displayed in mbar */
 		ui->airPressureText->setText(QString("%1mbar").arg(d->surface_pressure.mbar));
-- 
1.7.10.4