Merge pull request #628 from ispyisail/feature-wiring-db-tables

Add terminal and conductor tables to projectDataBase (discussion #503, slice 2)

sources/qetgraphicsitem/conductor.cpp

@@ -91,6 +91,7 @@ Conductor::Conductor(Terminal *p1, Terminal* p2) :
 		//set Zvalue at 11 to be upper than the DiagramImageItem and element
 	setZValue(11);
 	m_previous_z_value = zValue();
+	m_uuid = QUuid::createUuid();
 
 		//Add this conductor to the list of conductors of each of the two terminals
 	bool ajout_p1 = terminal1 -> addConductor(this);
@@ -1005,6 +1006,18 @@ void Conductor::pointsToSegments(const QList<QPointF>& points_list) {
 */
 bool Conductor::fromXml(QDomElement &dom_element)
 {
+		//Older project files have no conductor uuid attribute at all --
+		//generate one on load, same treatment terminal uuids got when
+		//that field was introduced (see terminal1/terminal2 handling in
+		//toXml() below).
+	m_uuid = QUuid(dom_element.attribute(QStringLiteral("uuid")));
+	if (m_uuid.isNull()) {
+			//Absent, empty or malformed: mint one. A null uuid is not a usable
+			//identity -- every conductor carrying one would collide with every
+			//other on the conductor table's primary key.
+		m_uuid = QUuid::createUuid();
+	}
+
 	setPos(dom_element.attribute("x", nullptr).toDouble(),
 		   dom_element.attribute("y", nullptr).toDouble());
 
@@ -1043,6 +1056,7 @@ QDomElement Conductor::toXml(QDomDocument &dom_document,
 {
 	QDomElement dom_element = dom_document.createElement("conductor");
 
+	dom_element.setAttribute("uuid", m_uuid.toString());
 	dom_element.setAttribute("x", QString::number(pos().x()));
 	dom_element.setAttribute("y", QString::number(pos().y()));
 	

sources/qetgraphicsitem/conductor.h

@@ -21,6 +21,7 @@
 #include "../conductorproperties.h"
 
 #include <QGraphicsPathItem>
+#include <QUuid>
 
 class ConductorProfile;
 class ConductorSegmentProfile;
@@ -77,6 +78,8 @@ class Conductor : public QGraphicsObject
 		int type() const override { return Type; }
 		Diagram *diagram() const;
 		ConductorTextItem *textItem() const;
+		QUuid uuid() const {return m_uuid;}
+		void newUuid() {m_uuid = QUuid::createUuid();}	//create new uuid for this conductor
 		void updatePath(const QRectF & = QRectF());
 
 		//This method do nothing, it's only made to be used with Q_PROPERTY
@@ -205,6 +208,7 @@ class Conductor : public QGraphicsObject
 		Highlight must_highlight_;
 		bool m_valid;
 		bool m_freeze_label = false;
+		QUuid m_uuid;
 
 			/// QPen et QBrush objects used to draw conductors
 		static QPen conductor_pen;

sources/qetgraphicsitem/terminal.cpp

@@ -820,6 +820,60 @@ QUuid Terminal::uuid() const
 	return d->m_uuid;
 }
 
+/**
+	@brief Terminal::stableUuid
+	An identity for this terminal that exists on every element, not only on
+	those saved by a uuid-aware element editor.
+
+	uuid() comes from the catalog .elmt definition and is empty for every
+	element authored before that field existed -- which is most of the
+	installed base. Anything keyed on uuid() alone therefore cannot see those
+	elements at all.
+
+	When there is no uuid, derive one from the terminal's local position and
+	orientation inside its element. That is not an arbitrary choice: it is the
+	same thing the project format itself uses to match a conductor back to a
+	terminal ("each connection is made by using the local position of the
+	terminal and a dynamic id" -- TerminalData::m_uuid). m_pos is the position
+	read from the definition and is not touched by moving the element on the
+	folio, so the result is stable across loads, saves and folio moves, and it
+	is unique within an element except where a definition genuinely declares
+	two terminals at the same point -- three cases in the whole example corpus,
+	and harmless, because two terminals sharing a position and orientation are
+	indistinguishable in every observable respect: they merge to one terminal
+	row and every conductor on either of them still resolves to the right
+	element and name.
+
+	Derived values are UUID v5 in a fixed namespace, so they are reproducible
+	without being written to the file, and cannot collide with the v4 uuids
+	the element editor generates.
+
+	@return the terminal's own uuid when it has one, otherwise a derived one
+*/
+QUuid Terminal::stableUuid() const
+{
+	if (!d->m_uuid.isNull()) {
+		return d->m_uuid;
+	}
+
+		//Fixed namespace for terminal identities derived from geometry.
+	static const QUuid derived_ns(QStringLiteral("{6b1f6d1e-6a1a-5f7e-9a3d-9c0a5b2d7e11}"));
+
+		//Position and orientation only. The name is deliberately excluded: it
+		//is not stable across a save cycle -- QET rewrites a terminal named
+		//"_" as unnamed, which would silently change the identity of 1421 of
+		//industrial.qet's 1790 terminals on the first resave. It is also not
+		//needed: keying on geometry alone produces exactly the same number of
+		//collisions across the example corpus, and it means renaming a
+		//terminal does not change what it is.
+	const QString key = QStringLiteral("%1|%2|%3")
+			.arg(d->m_pos.x(), 0, 'f', 4)
+			.arg(d->m_pos.y(), 0, 'f', 4)
+			.arg(static_cast<int>(d->m_orientation));
+
+	return QUuid::createUuidV5(derived_ns, key);
+}
+
 QString Terminal::name() const
 {
 	if (d->m_use_master_label && parent_element_) {

sources/qetgraphicsitem/terminal.h

@@ -75,6 +75,7 @@ class Terminal : public QGraphicsObject
 		Diagram  *diagram             () const;
 		Element  *parentElement       () const;
 		QUuid     uuid                () const;
+		QUuid     stableUuid          () const;
 		QString   name                () const;
 		QString   baseName            () const;
 		TerminalData::Type terminalType() const;