Merge pull request #140 from open-ephys-plugins/issue-139

Check if canvas exists before accessing it

Author: bparks13

Source/OnixSourceEditor.cpp

@@ -416,6 +416,12 @@ void OnixSourceEditor::comboBoxChanged(ComboBox* cb)
 
 void OnixSourceEditor::updateComboBox(ComboBox* cb)
 {
+	if (canvas == nullptr)
+	{
+		Onix1::showWarningMessageBoxAsync("Missing Canvas", missingCanvasErrorMessage);
+		return;
+	}
+
 	bool isPortA = cb == headstageComboBoxA.get();
 
 	PortName currentPort = isPortA ? PortName::PortA : PortName::PortB;
@@ -432,6 +438,7 @@ void OnixSourceEditor::updateComboBox(ComboBox* cb)
 		std::string headstage = isPortA ? headstageComboBoxA->getText().toStdString() : headstageComboBoxB->getText().toStdString();
 
 		source->updateDiscoveryParameters(currentPort, PortController::getHeadstageDiscoveryParameters(headstage));
+
 		canvas->addHub(headstage, PortController::getPortOffset(currentPort));
 
 		if (headstage == NEUROPIXELSV2E_HEADSTAGE_NAME || headstage == NEUROPIXELSV1E_HEADSTAGE_NAME)
@@ -631,6 +638,12 @@ void OnixSourceEditor::setComboBoxSelection(ComboBox* comboBox, std::string head
 
 void OnixSourceEditor::refreshComboBoxSelection()
 {
+	if (canvas == nullptr)
+	{
+		Onix1::showWarningMessageBoxAsync("Missing Canvas", missingCanvasErrorMessage);
+		return;
+	}
+
 	Array<CustomTabComponent*> hubTabs = canvas->getHubTabs();
 
 	bool resetPortA = true, resetPortB = true;
@@ -657,6 +670,12 @@ void OnixSourceEditor::refreshComboBoxSelection()
 
 OnixDeviceMap OnixSourceEditor::createTabMapFromCanvas()
 {
+	if (canvas == nullptr)
+	{
+		Onix1::showWarningMessageBoxAsync("Missing Canvas", missingCanvasErrorMessage);
+		return OnixDeviceMap{};
+	}
+
 	return canvas->getSelectedDevices(canvas->settingsInterfaces);
 }
 
@@ -675,6 +694,8 @@ void OnixSourceEditor::saveVisualizerEditorParameters(XmlElement* xml)
 
 void OnixSourceEditor::loadVisualizerEditorParameters(XmlElement* xml)
 {
+	checkForCanvas();
+
 	LOGD("Loading OnixSourceEditor settings.");
 
 	if (xml->hasAttribute("headstagePortA"))

Source/OnixSourceEditor.h

@@ -137,6 +137,8 @@ namespace OnixSourcePlugin
 
 		static constexpr int DefaultBlockReadSize = 4096;
 
+		static constexpr char* missingCanvasErrorMessage = "The canvas for this plugin could not be found. Some functionality may not work as expected, and you may not be able to acquire or record data. Try removing and replacing the plugin.";
+
 		JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR(OnixSourceEditor);
 	};
 }