Resolve circular imports for CuraAPI

cura/API/Account.py

@@ -1,15 +1,18 @@
 # Copyright (c) 2018 Ultimaker B.V.
 # Cura is released under the terms of the LGPLv3 or higher.
-from typing import Optional, Dict
+from typing import Optional, Dict, TYPE_CHECKING
 
 from PyQt5.QtCore import QObject, pyqtSignal, pyqtSlot, pyqtProperty
 
+from UM.i18n import i18nCatalog
 from UM.Message import Message
+
 from cura.OAuth2.AuthorizationService import AuthorizationService
 from cura.OAuth2.Models import OAuth2Settings
-from UM.Application import Application
 
-from UM.i18n import i18nCatalog
+if TYPE_CHECKING:
+    from cura.CuraApplication import CuraApplication
+
 i18n_catalog = i18nCatalog("cura")
 
 
@@ -26,8 +29,9 @@ class Account(QObject):
     # Signal emitted when user logged in or out.
     loginStateChanged = pyqtSignal(bool)
 
-    def __init__(self, parent = None) -> None:
+    def __init__(self, application: "CuraApplication", parent = None) -> None:
         super().__init__(parent)
+        self._application = application
 
         self._error_message = None  # type: Optional[Message]
         self._logged_in = False
@@ -47,7 +51,11 @@ class Account(QObject):
             AUTH_FAILED_REDIRECT="{}/app/auth-error".format(self._oauth_root)
         )
 
-        self._authorization_service = AuthorizationService(Application.getInstance().getPreferences(), self._oauth_settings)
+        self._authorization_service = AuthorizationService(self._oauth_settings)
+
+    def initialize(self) -> None:
+        self._authorization_service.initialize(self._application.getPreferences())
+
         self._authorization_service.onAuthStateChanged.connect(self._onLoginStateChanged)
         self._authorization_service.onAuthenticationError.connect(self._onLoginStateChanged)
         self._authorization_service.loadAuthDataFromPreferences()

cura/API/Backups.py

@@ -1,9 +1,12 @@
 # Copyright (c) 2018 Ultimaker B.V.
 # Cura is released under the terms of the LGPLv3 or higher.
-from typing import Tuple, Optional
+from typing import Tuple, Optional, TYPE_CHECKING
 
 from cura.Backups.BackupsManager import BackupsManager
 
+if TYPE_CHECKING:
+    from cura.CuraApplication import CuraApplication
+
 
 ##  The back-ups API provides a version-proof bridge between Cura's
 #   BackupManager and plug-ins that hook into it.
@@ -13,9 +16,10 @@ from cura.Backups.BackupsManager import BackupsManager
 #       api = CuraAPI()
 #       api.backups.createBackup()
 #       api.backups.restoreBackup(my_zip_file, {"cura_release": "3.1"})``
-
 class Backups:
-    manager = BackupsManager()  # Re-used instance of the backups manager.
+
+    def __init__(self, application: "CuraApplication") -> None:
+        self.manager = BackupsManager(application)
 
     ##  Create a new back-up using the BackupsManager.
     #   \return Tuple containing a ZIP file with the back-up data and a dict

cura/API/Interface/Settings.py

@@ -1,7 +1,11 @@
 # Copyright (c) 2018 Ultimaker B.V.
 # Cura is released under the terms of the LGPLv3 or higher.
 
-from cura.CuraApplication import CuraApplication
+from typing import TYPE_CHECKING
+
+if TYPE_CHECKING:
+    from cura.CuraApplication import CuraApplication
+
 
 ##  The Interface.Settings API provides a version-proof bridge between Cura's
 #   (currently) sidebar UI and plug-ins that hook into it.
@@ -19,8 +23,9 @@ from cura.CuraApplication import CuraApplication
 #       api.interface.settings.addContextMenuItem(data)``
 
 class Settings:
-    # Re-used instance of Cura:
-    application = CuraApplication.getInstance()  # type: CuraApplication
+
+    def __init__(self, application: "CuraApplication") -> None:
+        self.application = application
 
     ##  Add items to the sidebar context menu.
     #   \param menu_item dict containing the menu item to add.
@@ -30,4 +35,4 @@ class Settings:
     ##  Get all custom items currently added to the sidebar context menu.
     #   \return List containing all custom context menu items.
     def getContextMenuItems(self) -> list:
-        return self.application.getSidebarCustomMenuItems()
+        return self.application.getSidebarCustomMenuItems()

cura/API/Interface/__init__.py

@@ -1,9 +1,15 @@
 # Copyright (c) 2018 Ultimaker B.V.
 # Cura is released under the terms of the LGPLv3 or higher.
 
+from typing import TYPE_CHECKING
+
 from UM.PluginRegistry import PluginRegistry
 from cura.API.Interface.Settings import Settings
 
+if TYPE_CHECKING:
+    from cura.CuraApplication import CuraApplication
+
+
 ##  The Interface class serves as a common root for the specific API
 #   methods for each interface element.
 #
@@ -20,5 +26,6 @@ class Interface:
     # For now we use the same API version to be consistent.
     VERSION = PluginRegistry.APIVersion
 
-    # API methods specific to the settings portion of the UI
-    settings = Settings()
+    def __init__(self, application: "CuraApplication") -> None:
+        # API methods specific to the settings portion of the UI
+        self.settings = Settings(application)

cura/API/__init__.py

@@ -1,5 +1,7 @@
 # Copyright (c) 2018 Ultimaker B.V.
 # Cura is released under the terms of the LGPLv3 or higher.
+from typing import Optional, TYPE_CHECKING
+
 from PyQt5.QtCore import QObject, pyqtProperty
 
 from UM.PluginRegistry import PluginRegistry
@@ -7,6 +9,9 @@ from cura.API.Backups import Backups
 from cura.API.Interface import Interface
 from cura.API.Account import Account
 
+if TYPE_CHECKING:
+    from cura.CuraApplication import CuraApplication
+
 
 ##  The official Cura API that plug-ins can use to interact with Cura.
 #
@@ -19,14 +24,30 @@ class CuraAPI(QObject):
     # For now we use the same API version to be consistent.
     VERSION = PluginRegistry.APIVersion
 
-    # Backups API
-    backups = Backups()
+    def __init__(self, application: "CuraApplication") -> None:
+        super().__init__(parent = application)
+        self._application = application
 
-    # Interface API
-    interface = Interface()
+        # Accounts API
+        self._account = Account(self._application)
 
-    _account = Account()
+        # Backups API
+        self._backups = Backups(self._application)
+
+        # Interface API
+        self._interface = Interface(self._application)
+
+    def initialize(self) -> None:
+        self._account.initialize()
 
     @pyqtProperty(QObject, constant = True)
-    def account(self) -> Account:
-        return CuraAPI._account
+    def account(self) -> "Account":
+        return self._account
+
+    @property
+    def backups(self) -> "Backups":
+        return self._backups
+
+    @property
+    def interface(self) -> "Interface":
+        return self._interface