Add, move or remove a folio without building the others (stage D5)

Adding, moving or removing a folio rewrote every folio's position in
the project database through diagrams(), which builds every folio: 3 s
on a 50-folio project opened lazily. A folio not built has its position
and title block already, so folios() is enough. The list of tables a
table can continue builds only the folios holding a table (from the
index of a .qetz), and the wiring list's count of wires left out looks
at built folios only: reading a wire drops it unless both its ends are
found.

tst_lazyfolios: a folio added, moved and removed builds no other, with
the folios' rows as when every folio is built (fails with diagrams():
47 built); the tables listed as when built, building the 12 folios that
hold one (fails when every folio is built). ctest 96/96 eager and lazy;
342 corpus projects save the same in all four arms.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

sources/dataBase/projectdatabase.cpp

@@ -1536,8 +1536,10 @@ int projectDataBase::excludedConductorCount() const
 		return 0;
 	}
 
+		//A folio not built (QET_LAZY_FOLIOS) has none: reading a wire
+		//drops it unless both its ends are found (Conductor::fromXml())
 	int count = 0;
-	for (auto *diagram : m_project->diagrams())
+	for (auto *diagram : m_project->builtFolios())
 	{
 		const auto conductor_list = diagram->conductors();
 		for (auto *conductor : conductor_list)
@@ -1722,11 +1724,12 @@ void projectDataBase::flushElementPositions()
 /**
 	@brief projectDataBase::updateFolioPositions
 	Write every folio's position and folio number again, after a folio was
-	added, removed or moved.
+	added, removed or moved. A folio not built yet (QET_LAZY_FOLIOS) has
+	its position and title block already: it is not built for this.
 */
 void projectDataBase::updateFolioPositions()
 {
-	for (auto diagram : m_project->diagrams())
+	for (auto diagram : m_project->folios())
 	{
 		m_diagram_order_changed.bindValue(":pos", m_project->folioIndex(diagram)+1);
 		m_diagram_order_changed.bindValue(":uuid", diagram->uuid().toString());

sources/elementprovider.cpp

@@ -199,7 +199,14 @@ QVector<QetGraphicsTableItem *> ElementProvider::table(
 		}
 	}
 
-	for (auto d : allFolios()) {
+		//Only the folios holding a table are built for it
+	QList<Diagram *> folios = m_diagram_list;
+	if (m_project) {
+		m_project->buildFoliosHoldingTables();
+		folios = m_project->builtFolios();
+		folios.removeOne(m_excluded);
+	}
+	for (auto d : std::as_const(folios)) {
 		for (auto item_ : d->items())
 		{
 			if(item_->type() == QetGraphicsTableItem::Type)

sources/qetproject.cpp

@@ -2978,6 +2978,27 @@ bool QETProject::usesElement(const ElementsLocation &location) const
 	return(unbuiltFolioElements().contains(location));
 }
 
+/**
+	@brief QETProject::buildFoliosHoldingTables
+	Build the folios not built yet (QET_LAZY_FOLIOS) that hold a drawn
+	table, found from the index the project was opened from when it has
+	one: what a list of the project's tables needs, and no more
+*/
+void QETProject::buildFoliosHoldingTables()
+{
+	QList<Diagram *> to_build;
+	for (Diagram *d : std::as_const(m_diagrams_list))
+		if (!d->isLoaded() && unbuiltFolioHasTables(d))
+			to_build << d;
+	if (to_build.isEmpty()) {
+		return;
+	}
+	if (qEnvironmentVariableIntValue("QET_LAZY_FOLIOS_TRACE") == 1) {
+		qWarning().noquote() << "lazy folios:" << to_build.size() << "folios built for their tables";
+	}
+	buildFolios(to_build);
+}
+
 /**
 	@brief QETProject::unbuiltFolioHasTables
 	@return true if @p folio, not built yet (QET_LAZY_FOLIOS), has a drawn

sources/qetproject.h

@@ -135,6 +135,7 @@ class QETProject : public QObject
 		void buildPartnerSymbols(const QList<Diagram *> &folios, const QSet<QUuid> &partners);
 		void buildFoliosHolding(ElementData::Types kinds, bool free_only);
 		void buildFoliosHoldingSymbols(const QSet<QUuid> &symbols);
+		void buildFoliosHoldingTables();
 		QSet<QUuid> symbolsOnUnbuiltFolios() const;
 			/// While saving: the symbols on folios not built a built symbol
 			/// may be saved linked to (Element::toXml())

tests/qttest/lazy_folios_probe.cpp

@@ -725,6 +725,61 @@ int main(int argc, char **argv)
 				check(asked.folioPartsRead() == built, "asking a .qetz reads no file of a folio not built");
 			}
 
+				//A folio added, moved and removed: no other folio built, the
+				//folios' rows as when every folio is built (D5)
+			{
+				auto shuffle = [](QETProject &project) {
+					Diagram *added = project.addNewDiagram();
+					project.diagramOrderChanged(1, 0);
+					project.removeDiagram(added);
+				};
+				auto folioRows = [](QETProject &project) {
+					QStringList rows;
+					for (const QString &row : tables(project))
+						if (row.startsWith("diagram")) rows << row;
+					return rows;
+				};
+				QETProject shuffled(zipped);
+				const int unbuilt = shuffled.unloadedFolioCount();
+				shuffle(shuffled);
+				std::printf(".qetz folio added, moved, removed: %d folios built\n",
+							unbuilt - shuffled.unloadedFolioCount());
+				check(shuffled.unloadedFolioCount() == unbuilt, "adding, moving and removing a folio builds no other");
+				qunsetenv("QET_LAZY_FOLIOS");
+				QETProject usual_shuffled(zipped);
+				qputenv("QET_LAZY_FOLIOS", "1");
+				shuffle(usual_shuffled);
+				check(folioRows(shuffled) == folioRows(usual_shuffled), "folios' rows after a move as when built");
+			}
+
+				//The tables a table can continue (its properties editor) and
+				//the wiring list's count of wires left out: only the folios
+				//holding a table built (D5)
+			{
+				QETProject listed(zipped);
+				const int unbuilt = listed.unloadedFolioCount();
+				auto tableUuids = [](const QVector<QetGraphicsTableItem *> &list) {
+					QStringList uuids;
+					for (QetGraphicsTableItem *table : list) uuids << table->uuid().toString();
+					uuids.sort();
+					return uuids;
+				};
+				const QStringList lazy_tables = tableUuids(ElementProvider(&listed).table(nullptr, nullptr));
+				check(!lazy_tables.isEmpty(), "the project has tables");
+				check(lazy_tables == tableUuids(ElementProvider(&eager).table(nullptr, nullptr)),
+					  "the project's tables listed as when built");
+				check(listed.dataBase()->excludedConductorCount() == eager.dataBase()->excludedConductorCount(),
+					  "wires left out of the wiring list counted as when built");
+				int with_tables = 0;
+				for (Diagram *folio : folios) {
+					for (QGraphicsItem *item : folio->items())
+						if (item->type() == QetGraphicsTableItem::Type) { ++with_tables; break; }
+				}
+				std::printf(".qetz tables listed: %d folios built, %d hold a table\n",
+							unbuilt - listed.unloadedFolioCount(), with_tables);
+				check(listed.unloadedFolioCount() > 0, "listing the tables does not build every folio");
+			}
+
 				//Saved as a .qetz without building the folios not touched
 				//(D4): their parts and rows copied as they were
 			QETProject untouched(zipped);