Clean up preference saving code

The old code (on purpose) didn't try to differentiate "nonexisting
boolean configuration" with "existing boolean configuration set to
false", which is problematic if we optimize the saving to not save
default preferences at all.

Which this does.

So in addition to the logic to know about default preferences, this has
to change the interfaces for the PREF_BOOL reading code so that you can
tell the difference between "no value" and "false".

And since the previous calling convention was an abomination of doing
pointer casting and having case-statements for the config types, change
that while at it.  Both from a usage perspective *and* from a back-end
perspective it is actually much simpler to just have different functions
for the string vs boolean config read/write versions.  The OSX versions
in particular end up being one-liners.

(The GConf library is a nightmare, and doesn't seem to have any way to
know whether a boolean value exists or not, so you have to read it as a
GConfVal and then turn it into a gboolean rather than just get the "oh,
it didn't exist" as an error value).

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

1 files changed, 98 insertions, 70 deletions

diff --git a/gtk-gui.c b/gtk-gui.c
index b6904045b..4dcffbddc 100644
--- a/gtk-gui.c
+++ b/gtk-gui.c
@@ -76,8 +76,8 @@ static void set_default_dive_computer(const char *vendor, const char *product)
 		free((void *)default_dive_computer_product);
 	default_dive_computer_vendor = strdup(vendor);
 	default_dive_computer_product = strdup(product);
-	subsurface_set_conf("dive_computer_vendor", PREF_STRING, vendor);
-	subsurface_set_conf("dive_computer_product", PREF_STRING, product);
+	subsurface_set_conf("dive_computer_vendor", vendor);
+	subsurface_set_conf("dive_computer_product", product);
 }
 
 static void set_default_dive_computer_device(const char *name)
@@ -89,7 +89,7 @@ static void set_default_dive_computer_device(const char *name)
 	if (default_dive_computer_device)
 		free((void *)default_dive_computer_device);
 	default_dive_computer_device = strdup(name);
-	subsurface_set_conf("dive_computer_device", PREF_STRING, name);
+	subsurface_set_conf("dive_computer_device", name);
 }
 
 void repaint_dive(void)
@@ -593,6 +593,19 @@ static void pick_default_file(GtkWidget *w, GtkButton *button)
 	gtk_widget_set_sensitive(parent, TRUE);
 }
 
+static void set_bool_conf(char *name, gboolean value, gboolean def)
+{
+	if (value == def) {
+		subsurface_unset_conf(name);
+		return;
+	}
+	subsurface_set_conf_bool(name, value);
+}
+#define __SAVE_BOOLEAN(name, field, value) \
+	set_bool_conf(name, prefs.field == value, default_prefs.field == value)
+#define SAVE_UNIT(name, field, value) __SAVE_BOOLEAN(name, units.field, value)
+#define SAVE_BOOL(name, field) __SAVE_BOOLEAN(name, field, TRUE)
+
 static void preferences_dialog(GtkWidget *w, gpointer data)
 {
 	int result;
@@ -858,34 +871,39 @@ static void preferences_dialog(GtkWidget *w, gpointer data)
 
 		update_screen();
 
-		subsurface_set_conf("feet", PREF_BOOL, BOOL_TO_PTR(prefs.units.length == FEET));
-		subsurface_set_conf("psi", PREF_BOOL, BOOL_TO_PTR(prefs.units.pressure == PSI));
-		subsurface_set_conf("cuft", PREF_BOOL, BOOL_TO_PTR(prefs.units.volume == CUFT));
-		subsurface_set_conf("fahrenheit", PREF_BOOL, BOOL_TO_PTR(prefs.units.temperature == FAHRENHEIT));
-		subsurface_set_conf("lbs", PREF_BOOL, BOOL_TO_PTR(prefs.units.weight == LBS));
-
-		subsurface_set_conf("TEMPERATURE", PREF_BOOL, BOOL_TO_PTR(prefs.visible_cols.temperature));
-		subsurface_set_conf("TOTALWEIGHT", PREF_BOOL, BOOL_TO_PTR(prefs.visible_cols.totalweight));
-		subsurface_set_conf("SUIT", PREF_BOOL, BOOL_TO_PTR(prefs.visible_cols.suit));
-		subsurface_set_conf("CYLINDER", PREF_BOOL, BOOL_TO_PTR(prefs.visible_cols.cylinder));
-		subsurface_set_conf("NITROX", PREF_BOOL, BOOL_TO_PTR(prefs.visible_cols.nitrox));
-		subsurface_set_conf("SAC", PREF_BOOL, BOOL_TO_PTR(prefs.visible_cols.sac));
-		subsurface_set_conf("OTU", PREF_BOOL, BOOL_TO_PTR(prefs.visible_cols.otu));
-		subsurface_set_conf("MAXCNS", PREF_BOOL, BOOL_TO_PTR(prefs.visible_cols.maxcns));
-
-		subsurface_set_conf("divelist_font", PREF_STRING, divelist_font);
-
-		subsurface_set_conf("po2graph", PREF_BOOL, BOOL_TO_PTR(prefs.pp_graphs.po2));
-		subsurface_set_conf("pn2graph", PREF_BOOL, BOOL_TO_PTR(prefs.pp_graphs.pn2));
-		subsurface_set_conf("phegraph", PREF_BOOL, BOOL_TO_PTR(prefs.pp_graphs.phe));
-		subsurface_set_conf("po2threshold", PREF_STRING, po2_threshold_text);
-		subsurface_set_conf("pn2threshold", PREF_STRING, pn2_threshold_text);
-		subsurface_set_conf("phethreshold", PREF_STRING, phe_threshold_text);
-		subsurface_set_conf("redceiling", PREF_BOOL, BOOL_TO_PTR(prefs.profile_red_ceiling));
-		subsurface_set_conf("calcceiling", PREF_BOOL, BOOL_TO_PTR(prefs.profile_calc_ceiling));
-		subsurface_set_conf("calcceiling3m", PREF_BOOL, BOOL_TO_PTR(prefs.calc_ceiling_3m_incr));
-		subsurface_set_conf("gflow", PREF_STRING, gflow_text);
-		subsurface_set_conf("gfhigh", PREF_STRING, gfhigh_text);
+		SAVE_UNIT("feet", length, FEET);
+		SAVE_UNIT("psi", pressure, PSI);
+		SAVE_UNIT("cuft", volume, CUFT);
+		SAVE_UNIT("fahrenheit", temperature, FAHRENHEIT);
+		SAVE_UNIT("lbs", weight, LBS);
+
+		SAVE_BOOL("TEMPERATURE", visible_cols.temperature);
+		SAVE_BOOL("TOTALWEIGHT", visible_cols.totalweight);
+		SAVE_BOOL("SUIT", visible_cols.suit);
+		SAVE_BOOL("CYLINDER", visible_cols.cylinder);
+		SAVE_BOOL("NITROX", visible_cols.nitrox);
+		SAVE_BOOL("SAC", visible_cols.sac);
+		SAVE_BOOL("OTU", visible_cols.otu);
+		SAVE_BOOL("MAXCNS", visible_cols.maxcns);
+
+		subsurface_set_conf("divelist_font", divelist_font);
+
+		SAVE_BOOL("po2graph", pp_graphs.po2);
+		SAVE_BOOL("pn2graph", pp_graphs.pn2);
+		SAVE_BOOL("phegraph", pp_graphs.phe);
+
+		/* Fixme! Only save if different-from-default. unset if default */
+		subsurface_set_conf("po2threshold", po2_threshold_text);
+		subsurface_set_conf("pn2threshold", pn2_threshold_text);
+		subsurface_set_conf("phethreshold", phe_threshold_text);
+
+		SAVE_BOOL("redceiling", profile_red_ceiling);
+		SAVE_BOOL("calcceiling", profile_calc_ceiling);
+		SAVE_BOOL("calcceiling3m", calc_ceiling_3m_incr);
+
+		/* Fixme! Only save if different-from-default. unset if default */
+		subsurface_set_conf("gflow", gflow_text);
+		subsurface_set_conf("gfhigh", gfhigh_text);
 
 		new_default = strdup(gtk_button_get_label(GTK_BUTTON(xmlfile_button)));
 
@@ -899,7 +917,7 @@ static void preferences_dialog(GtkWidget *w, gpointer data)
 		}
 
 		if (strcmp(current_default, new_default)) {
-			subsurface_set_conf("default_filename", PREF_STRING, new_default);
+			subsurface_set_conf("default_filename", new_default);
 			free((void *)default_filename);
 			default_filename = new_default;
 		}
@@ -1242,6 +1260,18 @@ static gboolean on_key_press(GtkWidget *w, GdkEventKey *event, GtkWidget *diveli
 	return FALSE;
 }
 
+static gboolean get_bool(char *name, gboolean def)
+{
+	int val = subsurface_get_conf_bool(name);
+	if (val < 0)
+		return def;
+	return val;
+}
+#define GET_UNIT(name, field, f, t) \
+	prefs.units.field = get_bool(name, default_prefs.units.field) ? (t) : (f)
+#define GET_BOOL(name, field) \
+	prefs.field = get_bool(name, default_prefs.field)
+
 void init_ui(int *argcp, char ***argvp)
 {
 	GtkWidget *win;
@@ -1274,68 +1304,66 @@ void init_ui(int *argcp, char ***argvp)
 	g_type_init();
 
 	subsurface_open_conf();
-	if (subsurface_get_conf("feet", PREF_BOOL))
-		prefs.units.length = FEET;
-	if (subsurface_get_conf("psi", PREF_BOOL))
-		prefs.units.pressure = PSI;
-	if (subsurface_get_conf("cuft", PREF_BOOL))
-		prefs.units.volume = CUFT;
-	if (subsurface_get_conf("fahrenheit", PREF_BOOL))
-		prefs.units.temperature = FAHRENHEIT;
-	if (subsurface_get_conf("lbs", PREF_BOOL))
-		prefs.units.weight = LBS;
-	/* an unset key is FALSE - all these are hidden by default */
-	prefs.visible_cols.cylinder = PTR_TO_BOOL(subsurface_get_conf("CYLINDER", PREF_BOOL));
-	prefs.visible_cols.temperature = PTR_TO_BOOL(subsurface_get_conf("TEMPERATURE", PREF_BOOL));
-	prefs.visible_cols.totalweight = PTR_TO_BOOL(subsurface_get_conf("TOTALWEIGHT", PREF_BOOL));
-	prefs.visible_cols.suit = PTR_TO_BOOL(subsurface_get_conf("SUIT", PREF_BOOL));
-	prefs.visible_cols.nitrox = PTR_TO_BOOL(subsurface_get_conf("NITROX", PREF_BOOL));
-	prefs.visible_cols.otu = PTR_TO_BOOL(subsurface_get_conf("OTU", PREF_BOOL));
-	prefs.visible_cols.maxcns = PTR_TO_BOOL(subsurface_get_conf("MAXCNS", PREF_BOOL));
-	prefs.visible_cols.sac = PTR_TO_BOOL(subsurface_get_conf("SAC", PREF_BOOL));
-	prefs.pp_graphs.po2 = PTR_TO_BOOL(subsurface_get_conf("po2graph", PREF_BOOL));
-	prefs.pp_graphs.pn2 = PTR_TO_BOOL(subsurface_get_conf("pn2graph", PREF_BOOL));
-	prefs.pp_graphs.phe = PTR_TO_BOOL(subsurface_get_conf("phegraph", PREF_BOOL));
-	conf_value = subsurface_get_conf("po2threshold", PREF_STRING);
+
+	GET_UNIT("feet", length, METERS, FEET);
+	GET_UNIT("psi", pressure, BAR, PSI);
+	GET_UNIT("cuft", volume, LITER, CUFT);
+	GET_UNIT("fahrenheit", temperature, CELSIUS, FAHRENHEIT);
+	GET_UNIT("lbs", weight, KG, LBS);
+
+	/* an unset key is 'default' */
+	GET_BOOL("CYLINDER", visible_cols.cylinder);
+	GET_BOOL("TEMPERATURE", visible_cols.temperature);
+	GET_BOOL("TOTALWEIGHT", visible_cols.totalweight);
+	GET_BOOL("SUIT", visible_cols.suit);
+	GET_BOOL("NITROX", visible_cols.nitrox);
+	GET_BOOL("OTU", visible_cols.otu);
+	GET_BOOL("MAXCNS", visible_cols.maxcns);
+	GET_BOOL("SAC", visible_cols.sac);
+	GET_BOOL("po2graph", pp_graphs.po2);
+	GET_BOOL("pn2graph", pp_graphs.pn2);
+	GET_BOOL("phegraph", pp_graphs.phe);
+
+	conf_value = subsurface_get_conf("po2threshold");
 	if (conf_value) {
 		sscanf(conf_value, "%lf", &prefs.pp_graphs.po2_threshold);
 		free((void *)conf_value);
 	}
-	conf_value = subsurface_get_conf("pn2threshold", PREF_STRING);
+	conf_value = subsurface_get_conf("pn2threshold");
 	if (conf_value) {
 		sscanf(conf_value, "%lf", &prefs.pp_graphs.pn2_threshold);
 		free((void *)conf_value);
 	}
-	conf_value = subsurface_get_conf("phethreshold", PREF_STRING);
+	conf_value = subsurface_get_conf("phethreshold");
 	if (conf_value) {
 		sscanf(conf_value, "%lf", &prefs.pp_graphs.phe_threshold);
 		free((void *)conf_value);
 	}
-	prefs.profile_red_ceiling = PTR_TO_BOOL(subsurface_get_conf("redceiling", PREF_BOOL));
-	prefs.profile_calc_ceiling = PTR_TO_BOOL(subsurface_get_conf("calcceiling", PREF_BOOL));
-	prefs.calc_ceiling_3m_incr = PTR_TO_BOOL(subsurface_get_conf("calcceiling3m", PREF_BOOL));
-	conf_value = subsurface_get_conf("gflow", PREF_STRING);
+	GET_BOOL("redceiling", profile_red_ceiling);
+	GET_BOOL("calcceiling", profile_calc_ceiling);
+	GET_BOOL("calcceiling3m", calc_ceiling_3m_incr);
+	conf_value = subsurface_get_conf("gflow");
 	if (conf_value) {
 		sscanf(conf_value, "%lf", &prefs.gflow);
 		prefs.gflow /= 100.0;
 		set_gf(prefs.gflow, -1.0);
 		free((void *)conf_value);
 	}
-	conf_value = subsurface_get_conf("gfhigh", PREF_STRING);
+	conf_value = subsurface_get_conf("gfhigh");
 	if (conf_value) {
 		sscanf(conf_value, "%lf", &prefs.gfhigh);
 		prefs.gfhigh /= 100.0;
 		set_gf(-1.0, prefs.gfhigh);
 		free((void *)conf_value);
 	}
-	divelist_font = subsurface_get_conf("divelist_font", PREF_STRING);
+	divelist_font = subsurface_get_conf("divelist_font");
 
-	default_filename = subsurface_get_conf("default_filename", PREF_STRING);
+	default_filename = subsurface_get_conf("default_filename");
 
-	default_dive_computer_vendor = subsurface_get_conf("dive_computer_vendor", PREF_STRING);
-	default_dive_computer_product = subsurface_get_conf("dive_computer_product", PREF_STRING);
-	default_dive_computer_device = subsurface_get_conf("dive_computer_device", PREF_STRING);
-	conf_value = subsurface_get_conf("dc_nicknames", PREF_STRING);
+	default_dive_computer_vendor = subsurface_get_conf("dive_computer_vendor");
+	default_dive_computer_product = subsurface_get_conf("dive_computer_product");
+	default_dive_computer_device = subsurface_get_conf("dive_computer_device");
+	conf_value = subsurface_get_conf("dc_nicknames");
 	nicknamestring = strdup("");
 	if (conf_value) {
 		char *next_token, *nickname, *model, *conf_copy;
@@ -2288,7 +2316,7 @@ void remove_dc(const char *model, uint32_t deviceid, gboolean change_conf)
 	memmove(nnstring, brace, strlen(brace) + 1);
 
 	if (change_conf)
-		subsurface_set_conf("dc_nicknames", PREF_STRING, nicknamestring);
+		subsurface_set_conf("dc_nicknames", nicknamestring);
 
 bail:
 	free(entry);
@@ -2319,7 +2347,7 @@ void remember_dc(const char *model, uint32_t deviceid, const char *nickname, gbo
 		replace_nickname_nicknamestring(model, deviceid, nickname);
 	}
 	if (change_conf)
-		subsurface_set_conf("dc_nicknames", PREF_STRING, nicknamestring);
+		subsurface_set_conf("dc_nicknames", nicknamestring);
 }
 
 void set_dc_nickname(struct dive *dive)