Ensure corona::containments() is ordered

the order in which containments were restored used to be quite random:
ensure that's ordered by id this makes the shell startups be more reproduceable
from one to another, if a new containment arrives, ensure it's inserted
maintaining id order

containment::appelts() will need the same treatment

adds a test as well that checks the order is right

Change-Id: Ie1b278e5b83d7e3645f7293bf6d030aa7f43a221

autotests/coronatest.cpp

@@ -144,9 +144,7 @@ void CoronaTest::restore()
 {
     m_corona->loadLayout("plasma-test-appletsrc");
     QCOMPARE(m_corona->containments().count(), 3);
-    //TODO: check the order of m_corona->containments() is stable:
+
-    //at the moment the ordering seems pretty random
-    //same thing for the order of containment->applets()
     for (auto cont : m_corona->containments()) {
         switch (cont->id()) {
         case 1:
@@ -157,6 +155,21 @@ void CoronaTest::restore()
             break;
         }
     }
+
+
+}
+
+
+void CoronaTest::checkOrder()
+{
+    QCOMPARE(m_corona->containments().count(), 3);
+
+    //check containments order
+    QCOMPARE(m_corona->containments()[0]->id(), (uint)1);
+    QCOMPARE(m_corona->containments()[1]->id(), (uint)4);
+    QCOMPARE(m_corona->containments()[2]->id(), (uint)5);
+
+    //TODO: Containment::applets() order check
 }
 
 void CoronaTest::startupCompletion()

autotests/coronatest.h

@@ -84,6 +84,7 @@ public Q_SLOTS:
 
 private Q_SLOTS:
     void restore();
+    void checkOrder();
     void startupCompletion();
     void addRemoveApplets();
     void immutability();

src/plasma/corona.cpp

@@ -477,7 +477,11 @@ Containment *CoronaPrivate::addContainment(const QString &name, const QVariantLi
         conf.deleteGroup();
     }
 
-    containments.append(containment);
+    //make sure the containments are sorted by id
+    auto position = std::lower_bound(containments.begin(), containments.end(), containment, [](Plasma::Containment *c1,  Plasma::Containment *c2) {
+        return c1->id() < c2->id();
+    });
+    containments.insert(position, containment);
 
     QObject::connect(containment, SIGNAL(destroyed(QObject*)),
                      q, SLOT(containmentDestroyed(QObject*)));
@@ -514,8 +518,10 @@ QList<Plasma::Containment *> CoronaPrivate::importLayout(const KConfigGroup &con
     }
 
     KConfigGroup containmentsGroup(&conf, "Containments");
+    QStringList groups = containmentsGroup.groupList();
+    qSort(groups.begin(), groups.end());
 
-    foreach (const QString &group, containmentsGroup.groupList()) {
+    foreach (const QString &group, groups) {
         KConfigGroup containmentConfig(&containmentsGroup, group);
 
         if (containmentConfig.entryMap().isEmpty()) {