Dive site: implement purge of unused dive sites

Add a "purge unused dive sites" button to the dive site list.
Connect it to a new PurgeUnusedDiveSites command. Implementation
was trivial: simply copy the DeleteDiveSites command.

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

desktop-widgets/command.cpp

@@ -123,4 +123,9 @@ void mergeDiveSites(dive_site *ds, const QVector<dive_site *> &sites)
 	execute(new MergeDiveSites(ds, sites));
 }
 
+void purgeUnusedDiveSites()
+{
+	execute(new PurgeUnusedDiveSites);
+}
+
 } // namespace Command

desktop-widgets/command.h

@@ -49,6 +49,7 @@ void editDiveSiteLocation(dive_site *ds, location_t value);
 void editDiveSiteTaxonomy(dive_site *ds, taxonomy_data &value); // value is consumed (i.e. will be erased after call)!
 void addDiveSite(const QString &name);
 void mergeDiveSites(dive_site *ds, const QVector<dive_site *> &sites);
+void purgeUnusedDiveSites();
 
 } // namespace Command
 

desktop-widgets/command_divesite.cpp

@@ -105,6 +105,31 @@ void DeleteDiveSites::undo()
 	sitesToRemove = std::move(addDiveSites(sitesToAdd));
 }
 
+PurgeUnusedDiveSites::PurgeUnusedDiveSites()
+{
+	setText(tr("purge unused dive sites"));
+	for (int i = 0; i < dive_site_table.nr; ++i) {
+		dive_site *ds = dive_site_table.dive_sites[i];
+		if (ds->dives.nr == 0)
+			sitesToRemove.push_back(ds);
+	}
+}
+
+bool PurgeUnusedDiveSites::workToBeDone()
+{
+	return !sitesToRemove.empty();
+}
+
+void PurgeUnusedDiveSites::redo()
+{
+	sitesToAdd = std::move(removeDiveSites(sitesToRemove));
+}
+
+void PurgeUnusedDiveSites::undo()
+{
+	sitesToRemove = std::move(addDiveSites(sitesToAdd));
+}
+
 // Helper function: swap C and Qt string
 static void swap(char *&c, QString &q)
 {

desktop-widgets/command_divesite.h

@@ -43,6 +43,21 @@ private:
 	std::vector<OwningDiveSitePtr> sitesToAdd;
 };
 
+class PurgeUnusedDiveSites : public Base {
+public:
+	PurgeUnusedDiveSites();
+private:
+	bool workToBeDone() override;
+	void undo() override;
+	void redo() override;
+
+	// For redo
+	std::vector<dive_site *> sitesToRemove;
+
+	// For undo
+	std::vector<OwningDiveSitePtr> sitesToAdd;
+};
+
 class EditDiveSiteName : public Base {
 public:
 	EditDiveSiteName(dive_site *ds, const QString &name);

desktop-widgets/tab-widgets/TabDiveSite.cpp

@@ -69,3 +69,8 @@ void TabDiveSite::diveSiteChanged(struct dive_site *ds, int field)
 	QModelIndex localIdx = model.mapFromSource(globalIdx);
 	ui.diveSites->view()->scrollTo(localIdx);
 }
+
+void TabDiveSite::on_purgeUnused_clicked()
+{
+	Command::purgeUnusedDiveSites();
+}

desktop-widgets/tab-widgets/TabDiveSite.h

@@ -16,6 +16,7 @@ private slots:
 	void add();
 	void diveSiteAdded(struct dive_site *, int idx);
 	void diveSiteChanged(struct dive_site *ds, int field);
+	void on_purgeUnused_clicked();
 private:
 	Ui::TabDiveSite ui;
 	DiveSiteSortedModel model;

desktop-widgets/tab-widgets/TabDiveSite.ui

@@ -14,6 +14,13 @@
    <string>Dive sites</string>
   </property>
   <layout class="QVBoxLayout" name="verticalLayout">
+   <item>
+    <widget class="QToolButton" name="purgeUnused">
+     <property name="text">
+      <string>Purge unused dive sites</string>
+     </property>
+    </widget>
+   </item>
    <item>
     <widget class="TableView" name="diveSites" native="true"/>
    </item>