When the model of a qetgraphicstableitem is reseted (for exemple when
the sql query is modified) we check if there is useless tables (table
with 0 row displayed) and remove it.
When a qetgraphicstable is deleted, the next and previous table is not
aware about the deletion and keep a dangled pointer of the deleted table
who cause a segfault.
Like previous commit, in the method loadDiadrams() we call the method
diagramAdded(), in this method we call rebuildDiagramsMap()
updateAllTabsTitle() and these methods operate a loop for each existing
DiagramView.
Now loadDiagrams don't call diagramAdded (which must be used only when
user add a diagram during the use of QElectroTech) but make operations
itself and when all DiagramView are added, call rebuildDiagramsMap()
updateAllTabsTitle() only once.
In the methods readDiagramsXml we call addDiagram for each diagrams
loaded from xml, inside the addDiagram method we call the method
updateDiagramsFolioData() and to finish this method operate a loop for
each existing diagram.
Then when we load a project from xml of
10 folios, loop inside updateDiagramsFolioData() is called 55 time.
50 folios, loop inside updateDiagramsFolioData() is called 1275 time.
100 folios, loop inside updateDiagramsFolioData() is called 5050 time.
Now instead of call addDiagram, we add diagram directly inside the
methods readDiagramsXml and call the method updateDiagramsFolioData()
only once when all diagrams are loaded.
According to Qt creator flame graph, call QSettings take lot of time.
When loading the element collection, each items of the collection get
the current language by calling the function QString
QETApp::langFromSetting().
This function instantiate a QSettings object each time and take a lot of
time.
Now the QSettings is instantiate only at the first call, and the value
is stored in memory, then all other call of the function don't
instantiate a QSettings, but just return the value in memory.
