Addon Manager: Refactor to extract connection check GUI

src/Mod/AddonManager/addonmanager_connection_checker.py

@@ -0,0 +1,113 @@
+# ***************************************************************************
+# *                                                                         *
+# *   Copyright (c) 2022 FreeCAD Project Association                        *
+# *                                                                         *
+# *   This file is part of FreeCAD.                                         *
+# *                                                                         *
+# *   FreeCAD is free software: you can redistribute it and/or modify it    *
+# *   under the terms of the GNU Lesser General Public License as           *
+# *   published by the Free Software Foundation, either version 2.1 of the  *
+# *   License, or (at your option) any later version.                       *
+# *                                                                         *
+# *   FreeCAD is distributed in the hope that it will be useful, but        *
+# *   WITHOUT ANY WARRANTY; without even the implied warranty of            *
+# *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU      *
+# *   Lesser General Public License for more details.                       *
+# *                                                                         *
+# *   You should have received a copy of the GNU Lesser General Public      *
+# *   License along with FreeCAD. If not, see                               *
+# *   <https://www.gnu.org/licenses/>.                                      *
+# *                                                                         *
+# ***************************************************************************
+
+""" System for checking the network connection status asynchronously. """
+
+import FreeCAD
+
+from PySide import QtCore, QtWidgets
+
+import NetworkManager
+from addonmanager_workers_utility import ConnectionChecker
+
+translate = FreeCAD.Qt.translate
+
+
+class ConnectionCheckerGUI(QtCore.QObject):
+    """Determine whether there is an active network connection, showing a progress message if it
+    starts to take too long, and an error message if the network cannot be accessed."""
+
+    connection_available = QtCore.Signal()
+    check_complete = QtCore.Signal()
+
+    def __init__(self):
+        super().__init__()
+
+        # Check the connection in a new thread, so FreeCAD stays responsive
+        self.connection_checker = ConnectionChecker()
+        self.connection_checker.success.connect(self._check_succeeded)
+        self.connection_checker.failure.connect(self._network_connection_failed)
+
+        self.connection_message_timer = None
+        self.connection_check_message = None
+
+    def start(self):
+        """Start the connection check"""
+        self.connection_checker.start()
+
+        # If it takes longer than a half second to check the connection, show a message:
+        self.connection_message_timer = QtCore.QTimer.singleShot(
+            500, self._show_connection_check_message
+        )
+
+    def _show_connection_check_message(self):
+        """Display a message informing the user that the check is in process"""
+        if not self.connection_checker.isFinished():
+            self.connection_check_message = QtWidgets.QMessageBox(
+                QtWidgets.QMessageBox.Information,
+                translate("AddonsInstaller", "Checking connection"),
+                translate("AddonsInstaller", "Checking for connection to GitHub..."),
+                QtWidgets.QMessageBox.Cancel,
+            )
+            self.connection_check_message.buttonClicked.connect(
+                self.cancel_network_check
+            )
+            self.connection_check_message.show()
+
+    def cancel_network_check(self, _):
+        """Cancel the check"""
+        if not self.connection_checker.isFinished():
+            self.connection_checker.success.disconnect(self.launch)
+            self.connection_checker.failure.disconnect(self.network_connection_failed)
+            self.connection_checker.requestInterruption()
+            self.connection_checker.wait(500)
+            self.connection_check_message.close()
+            self.check_complete.emit()
+
+    def _network_connection_failed(self, message: str) -> None:
+        """Callback for failed connection check. Displays an error message, then emits the
+        check_complete signal (but not the connection available signal)."""
+        # This must run on the main GUI thread
+        if hasattr(self, "connection_check_message") and self.connection_check_message:
+            self.connection_check_message.close()
+        if NetworkManager.HAVE_QTNETWORK:
+            QtWidgets.QMessageBox.critical(
+                None, translate("AddonsInstaller", "Connection failed"), message
+            )
+        else:
+            #pylint: disable=line-too-long
+            QtWidgets.QMessageBox.critical(
+                None,
+                translate("AddonsInstaller", "Missing dependency"),
+                translate(
+                    "AddonsInstaller",
+                    "Could not import QtNetwork -- see Report View for details. Addon Manager unavailable.",
+                ),
+            )
+
+        self.check_complete.emit()
+
+    def _check_succeeded(self):
+        """Emit both the connection_available and the check_complete signals, in that order."""
+
+        self.connection_available.emit()
+        self.check_complete.emit()