cleanup: invert control-flow when resetting the core structures

To reset the core data structures, the mobile and desktop UIs
were calling into the dive-list models, which then reset the
core data structures, themselves and the unrelated
locationinformation model. The UI code then reset various other
things, such as the TankInformation model or the map. . This was
unsatisfying from a control-flow perspective, as the models should
display the core data, not act on it. Moreover, this meant lots
of intricate intermodule-dependencies.

Thus, straighten up the control flow: give the C core the
possibility to send a "all data reset" event. And do that
in those functions that reset the core data structures.
Let each module react to this event by itself. This removes
inter-module dependencies. For example, the MainWindow now
doesn't have to reset the TankInfoModel or the MapWidget.

Then, to reset the core data structures, let the UI code
simply directly call the respective core functions.

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

core/divelist.c

@@ -835,6 +835,9 @@ void process_loaded_dives()
 	autogroup_dives(&dive_table, &trip_table);
 
 	fulltext_populate();
+
+	/* Inform frontend of reset data. This should reset all the models. */
+	emit_reset_signal();
 }
 
 /*
@@ -1045,6 +1048,9 @@ void add_imported_dives(struct dive_table *import_table, struct trip_table *impo
 	 * Choose the newest dive as selected (if any) */
 	current_dive = dive_table.nr > 0 ? dive_table.dives[dive_table.nr - 1] : NULL;
 	mark_divelist_changed(true);
+
+	/* Inform frontend of reset data. This should reset all the models. */
+	emit_reset_signal();
 }
 
 /* Helper function for process_imported_dives():
@@ -1373,6 +1379,9 @@ void clear_dive_file_data()
 
 	reset_min_datafile_version();
 	clear_git_id();
+
+	/* Inform frontend of reset data. This should reset all the models. */
+	emit_reset_signal();
 }
 
 bool dive_less_than(const struct dive *a, const struct dive *b)

core/qthelper.cpp

@@ -3,6 +3,7 @@
 #include "dive.h"
 #include "core/settings/qPrefLanguage.h"
 #include "core/settings/qPrefUpdateManager.h"
+#include "core/subsurface-qt/divelistnotifier.h"
 #include "subsurface-string.h"
 #include "subsurface-string.h"
 #include "gettextfromc.h"
@@ -1675,3 +1676,8 @@ std::vector<int> get_cylinder_map_for_add(int count, int n)
 	std::iota(mapping.begin() + n, mapping.end(), n + 1);
 	return mapping;
 }
+
+extern "C" void emit_reset_signal()
+{
+	emit diveListNotifier.dataReset();
+}

core/qthelper.h

@@ -155,6 +155,8 @@ pressure_t string_to_pressure(const char *str);
 volume_t string_to_volume(const char *str, pressure_t workp);
 fraction_t string_to_fraction(const char *str);
 char *get_changes_made();
+void emit_reset_signal();
+
 #ifdef __cplusplus
 }
 #endif

core/subsurface-qt/divelistnotifier.h

@@ -78,6 +78,9 @@ struct TripField {
 class DiveListNotifier : public QObject {
 	Q_OBJECT
 signals:
+	// The core structures were completely reset. Repopulate all models.
+	void dataReset();
+
 	// Note that there are no signals for trips being added and created
 	// because these events never happen without a dive being added, removed or moved.
 	// The dives are always sorted according to the dives_less_than() function of the core.