core: make owning pointers a top-level features

The undo-code uses owning pointers based on std::unique_ptr to
manage lifetime of C-objects. Since these are generally useful,
move them from the undo-code to the core-code. In fact, this
eliminates one instance of code duplication.

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

Subsurface-mobile.pro

@@ -206,6 +206,7 @@ HEADERS += \
 	core/extradata.h \
 	core/git-access.h \
 	core/globals.h \
+	core/owning_ptrs.h \
 	core/pref.h \
 	core/profile.h \
 	core/qthelper.h \

commands/command.h

@@ -30,8 +30,8 @@ void clear();				// Reset the undo stack. Delete all commands.
 void setClean();			// Call after save - this marks a state where no changes need to be saved.
 bool isClean();				// Any changes need to be saved?
 QAction *undoAction(QObject *parent);	// Create an undo action.
-QAction *redoAction(QObject *parent);	// Create an redo action.
-QString changesMade();			// return a string with the texts from all commands on the undo stack -> for commit message
+QAction *redoAction(QObject *parent);	// Create a redo action.
+QString changesMade();			// Return a string with the texts from all commands on the undo stack -> for commit message.
 bool placingCommand();			// Currently executing a new command -> might not have to update the field the user just edited.
 
 // 2) Dive-list related commands

commands/command_base.h

@@ -7,6 +7,7 @@
 #include "core/divesite.h"
 #include "core/trip.h"
 #include "core/dive.h"
+#include "core/owning_ptrs.h"
 
 #include <QUndoCommand>
 #include <QCoreApplication>	// For Q_DECLARE_TR_FUNCTIONS
@@ -153,26 +154,6 @@ QVector<T> stdToQt(const std::vector<T> &v)
 // We put everything in a namespace, so that we can shorten names without polluting the global namespace
 namespace Command {
 
-// Classes used to automatically call the appropriate free_*() function for owning pointers that go out of scope.
-struct DiveDeleter {
-	void operator()(dive *d) { free_dive(d); }
-};
-struct TripDeleter {
-	void operator()(dive_trip *t) { free_trip(t); }
-};
-struct DiveSiteDeleter {
-	void operator()(dive_site *ds) { free_dive_site(ds); }
-};
-struct EventDeleter {
-	void operator()(event *ev) { free(ev); }
-};
-
-// Owning pointers to dive, dive_trip, dive_site and event objects.
-typedef std::unique_ptr<dive, DiveDeleter> OwningDivePtr;
-typedef std::unique_ptr<dive_trip, TripDeleter> OwningTripPtr;
-typedef std::unique_ptr<dive_site, DiveSiteDeleter> OwningDiveSitePtr;
-typedef std::unique_ptr<event, EventDeleter> OwningEventPtr;
-
 // This is the base class of all commands.
 // It defines the Qt-translation functions
 class Base : public QUndoCommand {

core/CMakeLists.txt

@@ -132,6 +132,7 @@ set(SUBSURFACE_CORE_LIB_SRCS
 	metrics.cpp
 	metrics.h
 	ostctools.c
+	owning_ptrs.h
 	parse-gpx.cpp
 	parse-xml.c
 	parse.c

core/owning_ptrs.h

@@ -0,0 +1,41 @@
+// SPDX-License-Identifier: GPL-2.0
+// Convenience classes defining owning pointers to C-objects that
+// automatically clean up the objects if the pointers go out of
+// scope. Based on unique_ptr<>.
+// In the future, we should replace these by real destructors.
+#ifndef OWNING_PTR_H
+#define OWNING_PTR_H
+
+#include <memory>
+#include <cstdlib>
+
+struct dive;
+struct dive_trip;
+struct dive_site;
+struct event;
+
+extern "C" void free_dive(struct dive *);
+extern "C" void free_trip(struct dive_trip *);
+extern "C" void free_dive_site(struct dive_site *);
+
+// Classes used to automatically call the appropriate free_*() function for owning pointers that go out of scope.
+struct DiveDeleter {
+	void operator()(dive *d) { free_dive(d); }
+};
+struct TripDeleter {
+	void operator()(dive_trip *t) { free_trip(t); }
+};
+struct DiveSiteDeleter {
+	void operator()(dive_site *ds) { free_dive_site(ds); }
+};
+struct EventDeleter {
+	void operator()(event *ev) { free(ev); }
+};
+
+// Owning pointers to dive, dive_trip, dive_site and event objects.
+using OwningDivePtr = std::unique_ptr<dive, DiveDeleter>;
+using OwningTripPtr = std::unique_ptr<dive_trip, TripDeleter>;
+using OwningDiveSitePtr = std::unique_ptr<dive_site, DiveSiteDeleter>;
+using OwningEventPtr = std::unique_ptr<event, EventDeleter>;
+
+#endif

desktop-widgets/profilewidget.h

@@ -5,10 +5,10 @@
 #define PROFILEWIDGET_H
 
 #include "ui_profilewidget.h"
+#include "core/owning_ptrs.h"
 #include "core/subsurface-qt/divelistnotifier.h"
 
 #include <vector>
-#include <memory>
 
 struct dive;
 class ProfileWidget2;
@@ -40,11 +40,6 @@ slots:
 	void stopRemoved(int count);
 	void stopMoved(int count);
 private:
-	// The same code is in command/command_base.h. Should we make that a global feature?
-	struct DiveDeleter {
-		void operator()(dive *d) { free_dive(d); }
-	};
-
 	std::unique_ptr<EmptyView> emptyView;
 	std::vector<QAction *> toolbarActions;
 	Ui::ProfileWidget ui;
@@ -53,7 +48,7 @@ private:
 	void editDive();
 	void exitEditMode();
 	void rotateDC(int dir);
-	std::unique_ptr<dive, DiveDeleter> editedDive;
+	OwningDivePtr editedDive;
 	int editedDc;
 	dive *originalDive;
 	bool placingCommand;

mobile-widgets/qmlmanager.cpp

@@ -897,7 +897,7 @@ void QMLManager::refreshDiveList()
 // The following structure describes such a change caused by a dive edit.
 // Hopefully, we can remove this in due course by using finer-grained undo-commands.
 struct DiveSiteChange {
-	Command::OwningDiveSitePtr createdDs; // not-null if we created a dive site.
+	OwningDiveSitePtr createdDs; // not-null if we created a dive site.
 
 	dive_site *editDs = nullptr; // not-null if we are supposed to edit an existing dive site.
 	location_t location = zero_location; // new value of the location if we edit an existing dive site.
@@ -1181,7 +1181,7 @@ void QMLManager::commitChanges(QString diveId, QString number, QString date, QSt
 				      QStringLiteral("state   :'%1'\n").arg(state);
 	}
 
-	Command::OwningDivePtr d_ptr(alloc_dive()); // Automatically delete dive if we exit early!
+	OwningDivePtr d_ptr(alloc_dive()); // Automatically delete dive if we exit early!
 	dive *d = d_ptr.get();
 	copy_dive(orig, d);