Turn application state into enum

The application state was encoded in a QByteArray. Thus, there was
no compile-time checking. Typos would lead to silent failures.

Turn the application state into an enum. Use the enum-class construct,
so that the values don't polute the global namespace. Moreover,
this makes them strongly typed, i.e. they don't auto-convert to
integers.

A disadvantage is that the enums now have to be cast to int
explicitly when used to index an array.

Replace two hash-maps in MainWindow to arrays of fixed sizes.

Move the application-state details into their own files.

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

core/CMakeLists.txt

@@ -37,6 +37,8 @@ endif()
 
 # compile the core library part in C, part in C++
 set(SUBSURFACE_CORE_LIB_SRCS
+	applicationstate.cpp
+	applicationstate.h
 	checkcloudconnection.cpp
 	checkcloudconnection.h
 	cloudstorage.cpp

core/applicationstate.cpp

@@ -0,0 +1,15 @@
+// SPDX-License-Identifier: GPL-2.0
+#include "applicationstate.h"
+
+static ApplicationState appState = (ApplicationState)-1; // Set to an invalid value
+
+ApplicationState getAppState()
+{
+	return appState;
+}
+
+void setAppState(ApplicationState state)
+{
+	appState = state;
+}
+

core/applicationstate.h

@@ -0,0 +1,21 @@
+// SPDX-License-Identifier: GPL-2.0
+#ifndef APPLICATIONSTATE_H
+#define APPLICATIONSTATE_H
+
+// By using an enum class, the enum entries don't polute the global namespace.
+// Moreover, they are strongly typed. This means that they are not auto-converted
+// to integer types if e.g. used as array-indices.
+enum class ApplicationState {
+	Default,
+	EditDive,
+	PlanDive,
+	EditPlannedDive,
+	EditDiveSite,
+	FilterDive,
+	Count
+};
+
+ApplicationState getAppState();
+void setAppState(ApplicationState state);
+
+#endif

core/qthelper.cpp

@@ -12,6 +12,7 @@
 #include "divecomputer.h"
 #include "time.h"
 #include "gettextfromc.h"
+#include "applicationstate.h"
 #include "metadata.h"
 #include <sys/time.h>
 #include "exif.h"
@@ -1362,21 +1363,9 @@ extern "C" void parse_display_units(char *line)
 	qDebug() << line;
 }
 
-static QByteArray currentApplicationState;
-
-QByteArray getCurrentAppState()
-{
-	return currentApplicationState;
-}
-
-void setCurrentAppState(const QByteArray &state)
-{
-	currentApplicationState = state;
-}
-
 extern "C" bool in_planner()
 {
-	return currentApplicationState == "PlanDive" || currentApplicationState == "EditPlannedDive";
+	return getAppState() == ApplicationState::PlanDive || getAppState() == ApplicationState::EditPlannedDive;
 }
 
 extern "C" enum deco_mode decoMode()

core/qthelper.h

@@ -40,8 +40,6 @@ volume_t string_to_volume(const char *str, pressure_t workp);
 fraction_t string_to_fraction(const char *str);
 int getCloudURL(QString &filename);
 bool parseGpsText(const QString &gps_text, double *latitude, double *longitude);
-QByteArray getCurrentAppState();
-void setCurrentAppState(const QByteArray &state);
 void init_proxy();
 QString getUUID();
 extern const QStringList videoExtensionsList;