Cleanup: fix printGPSCoords signature and leaks

The printGPSCoords() function returns a copied C-style string. Since
the owndership is transferred to the caller, the correct return type
is "char *" instead of "const char *".

Thus a number of casts when calling free can be removed.

Moreover a number of callers didn't free the string and thus were
leaking memory. Fix them. Ultimately we might want two versions
of the function: one for QString, one for C-style strings.

Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>

6 files changed, 15 insertions, 8 deletions

diff --git a/core/gpslocation.cpp b/core/gpslocation.cpp
index e0b176f58..d0bbcdc8f 100644
--- a/core/gpslocation.cpp
+++ b/core/gpslocation.cpp
@@ -137,7 +137,9 @@ QString GpsLocation::currentPosition()
 		if (delta < 300) {
 			// we can simply use the last position that we tracked
 			gpsTracker gt = m_trackers.last();
-			QString gpsString = printGPSCoords(&gt.location);
+			char *gps = printGPSCoords(&gt.location);
+			QString gpsString = gps;
+			free(gps);
 			qDebug() << "returning last position" << gpsString;
 			return gpsString;
 		} else {
diff --git a/core/load-git.c b/core/load-git.c
index 08d9b7765..8417fc2e4 100644
--- a/core/load-git.c
+++ b/core/load-git.c
@@ -164,10 +164,10 @@ static void parse_dive_gps(char *line, struct membuffer *str, void *_dive)
 			dive->dive_site = ds;
 	} else {
 		if (dive_site_has_gps_location(ds) && !same_location(&ds->location, &location)) {
-			const char *coords = printGPSCoords(&location);
+			char *coords = printGPSCoords(&location);
 			// we have a dive site that already has GPS coordinates
 			ds->notes = add_to_string(ds->notes, translate("gettextFromC", "multiple GPS locations for this dive site; also %s\n"), coords);
-			free((void *)coords);
+			free(coords);
 		}
 		ds->location = location;
 	}
diff --git a/core/parse-xml.c b/core/parse-xml.c
index c2e2ef937..c118c89cc 100644
--- a/core/parse-xml.c
+++ b/core/parse-xml.c
@@ -1201,9 +1201,9 @@ static void gps_in_dive(char *buffer, struct dive *dive, struct parser_state *st
 			fprintf(stderr, "dive site uuid in dive, but gps location (%10.6f/%10.6f) different from dive location (%10.6f/%10.6f)\n",
 				ds->location.lat.udeg / 1000000.0, ds->location.lon.udeg / 1000000.0,
 				location.lat.udeg / 1000000.0, location.lon.udeg / 1000000.0);
-			const char *coords = printGPSCoords(&location);
+			char *coords = printGPSCoords(&location);
 			ds->notes = add_to_string(ds->notes, translate("gettextFromC", "multiple GPS locations for this dive site; also %s\n"), coords);
-			free((void *)coords);
+			free(coords);
 		} else {
 			ds->location = location;
 		}
diff --git a/core/qthelper.cpp b/core/qthelper.cpp
index 89dd1befb..26a8a68f9 100644
--- a/core/qthelper.cpp
+++ b/core/qthelper.cpp
@@ -72,7 +72,7 @@ QString distance_string(int distanceInMeters)
 	return str;
 }
 
-extern "C" const char *printGPSCoords(const location_t *location)
+extern "C" char *printGPSCoords(const location_t *location)
 {
 	int lat = location->lat.udeg;
 	int lon = location->lon.udeg;
diff --git a/core/qthelper.h b/core/qthelper.h
index 3e90a1979..ed09d70fb 100644
--- a/core/qthelper.h
+++ b/core/qthelper.h
@@ -123,7 +123,7 @@ void moveInVector(Vector &v, int rangeBegin, int rangeEnd, int destination)
 extern "C" {
 #endif
 
-const char *printGPSCoords(const location_t *loc);
+char *printGPSCoords(const location_t *loc);
 bool in_planner();
 bool getProxyString(char **buffer);
 bool canReachCloudServer();
diff --git a/core/subsurface-qt/DiveObjectHelper.cpp b/core/subsurface-qt/DiveObjectHelper.cpp
index 0742e382f..921d55bea 100644
--- a/core/subsurface-qt/DiveObjectHelper.cpp
+++ b/core/subsurface-qt/DiveObjectHelper.cpp
@@ -112,7 +112,12 @@ QString DiveObjectHelper::location() const
 QString DiveObjectHelper::gps() const
 {
 	struct dive_site *ds = m_dive->dive_site;
-	return ds ? QString(printGPSCoords(&ds->location)) : QString();
+	if (!ds)
+		return QString();
+	char *gps = printGPSCoords(&ds->location);
+	QString res = gps;
+	free(gps);
+	return res;
 }
 
 QString DiveObjectHelper::gps_decimal() const