Jupyter refactoring and cleanup

src/python/cutter_ipykernel.py

@@ -28,7 +28,7 @@ def launch_ipykernel(argv):
     def run_kernel():
         app = CutterIPKernelApp.instance()
         app.kernel_class = CutterIPythonKernel
-        app.log_level = logging.DEBUG
+        #app.log_level = logging.DEBUG
         app.initialize(argv[3:])
         app.start()
 

src/utils/JupyterConnection.cpp

@@ -11,6 +11,13 @@
 #include "JupyterConnection.h"
 #include "PythonAPI.h"
 
+Q_GLOBAL_STATIC(JupyterConnection, uniqueInstance)
+
+JupyterConnection *JupyterConnection::getInstance()
+{
+    return uniqueInstance;
+}
+
 JupyterConnection::JupyterConnection(QObject *parent) : QObject(parent)
 {
 }
@@ -24,18 +31,29 @@ JupyterConnection::~JupyterConnection()
         auto stopFunc = PyObject_GetAttrString(cutterNotebookAppInstance, "stop");
         PyObject_CallObject(stopFunc, nullptr);
         Py_DECREF(cutterNotebookAppInstance);
+    }
 
+    if (Py_IsInitialized())
+    {
         Py_FinalizeEx();
     }
 }
 
-void JupyterConnection::start()
+
+void JupyterConnection::initPython()
 {
     PyImport_AppendInittab("cutter", &PyInit_api);
     PyImport_AppendInittab("cutter_internal", &PyInit_api_internal);
     Py_Initialize();
     PyEval_InitThreads();
 
+    pyThreadState = PyEval_SaveThread();
+}
+
+void JupyterConnection::createCutterJupyterModule()
+{
+    PyEval_RestoreThread(pyThreadState);
+
     QFile moduleFile(":/python/cutter_jupyter.py");
     moduleFile.open(QIODevice::ReadOnly);
     QByteArray moduleCode = moduleFile.readAll();
@@ -46,6 +64,7 @@ void JupyterConnection::start()
     {
         qWarning() << "Could not compile cutter_jupyter.";
         emit creationFailed();
+        pyThreadState = PyEval_SaveThread();
         return;
     }
     cutterJupyterModule = PyImport_ExecCodeModule("cutter_jupyter", moduleCodeObject);
@@ -54,16 +73,54 @@ void JupyterConnection::start()
     {
         qWarning() << "Could not import cutter_jupyter.";
         emit creationFailed();
+        pyThreadState = PyEval_SaveThread();
         return;
     }
 
+    pyThreadState = PyEval_SaveThread();
+}
+
+void JupyterConnection::start()
+{
+    if (cutterNotebookAppInstance)
+    {
+        return;
+    }
+
+    if (!Py_IsInitialized())
+    {
+        initPython();
+    }
+
+    if (!cutterJupyterModule)
+    {
+        createCutterJupyterModule();
+    }
+
+    PyEval_RestoreThread(pyThreadState);
     auto startFunc = PyObject_GetAttrString(cutterJupyterModule, "start_jupyter");
     cutterNotebookAppInstance = PyObject_CallObject(startFunc, nullptr);
+    pyThreadState = PyEval_SaveThread();
+
+    emit urlReceived(getUrl());
+}
+
+QString JupyterConnection::getUrl()
+{
+    if (!cutterNotebookAppInstance)
+    {
+        return nullptr;
+    }
+
+    PyEval_RestoreThread(pyThreadState);
+
     auto urlWithToken = PyObject_GetAttrString(cutterNotebookAppInstance, "url_with_token");
     auto asciiBytes = PyUnicode_AsASCIIString(urlWithToken);
-    emit urlReceived(QString::fromUtf8(PyBytes_AsString(asciiBytes)));
+    auto urlWithTokenString = QString::fromUtf8(PyBytes_AsString(asciiBytes));
     Py_DECREF(asciiBytes);
     Py_DECREF(urlWithToken);
 
     pyThreadState = PyEval_SaveThread();
+
+    return urlWithTokenString;
 }

src/utils/JupyterConnection.h

@@ -14,10 +14,13 @@ class JupyterConnection : public QObject
     Q_OBJECT
 
 public:
+    static JupyterConnection* getInstance();
+
     JupyterConnection(QObject *parent = nullptr);
     ~JupyterConnection();
 
     void start();
+    QString getUrl();
 
 signals:
     void urlReceived(const QString &url);
@@ -28,6 +31,13 @@ private:
     PyObject *cutterNotebookAppInstance = nullptr;
 
     PyThreadState *pyThreadState = nullptr;
+
+    void initPython();
+    void createCutterJupyterModule();
 };
 
+
+#define Jupyter() (JupyterConnection::getInstance())
+
+
 #endif //JUPYTERCONNECTION_H

src/widgets/JupyterWidget.cpp

@@ -14,10 +14,9 @@ JupyterWidget::JupyterWidget(QWidget *parent, Qt::WindowFlags flags) :
 {
     ui->setupUi(this);
 
-    jupyter = new JupyterConnection(this);
-    connect(jupyter, &JupyterConnection::urlReceived, this, &JupyterWidget::urlReceived);
-    connect(jupyter, &JupyterConnection::creationFailed, this, &JupyterWidget::creationFailed);
-    jupyter->start();
+    connect(Jupyter(), &JupyterConnection::urlReceived, this, &JupyterWidget::urlReceived);
+    connect(Jupyter(), &JupyterConnection::creationFailed, this, &JupyterWidget::creationFailed);
+    Jupyter()->start();
 }
 
 JupyterWidget::~JupyterWidget()
@@ -48,6 +47,7 @@ void JupyterWidget::creationFailed()
     ui->tabWidget->addTab(failPage, tr("Error"));
 }
 
+
 JupyterWebView::JupyterWebView(JupyterWidget *mainWidget, QWidget *parent) : QWebEngineView(parent)
 {
     this->mainWidget = mainWidget;

src/widgets/JupyterWidget.h

@@ -32,8 +32,6 @@ private slots:
 
 private:
     std::unique_ptr<Ui::JupyterWidget> ui;
-
-    JupyterConnection *jupyter;
 };