Add flag to store and check canceled state of the packaging

Author: gounux

libqfieldsync/offline_converter.py

@@ -72,6 +72,13 @@ class LayerData(TypedDict):
     LayerData = Dict
 
 
+class PackagingCanceledException(Exception):
+    """Exception to be raised when offline converting is canceled"""
+
+    def __init__(self, *args):
+        super().__init__(QObject().tr("Packaging canceled by the user"), *args)
+
+
 class ExportType(Enum):
     Cable = "cable"
     Cloud = "cloud"
@@ -86,6 +93,8 @@ class OfflineConverter(QObject):
     # feedback used for basemap generation processing algorithm
     _feedback = QgsProcessingFeedback()
 
+    _is_canceled: bool = False
+
     def __init__(
         self,
         project: QgsProject,
@@ -206,7 +215,13 @@ def _convert(self, project: QgsProject) -> None:
         copied_files = list()
 
         if self.create_basemap and self.project_configuration.create_base_map:
-            self._export_basemap()
+            is_basemap_export_success = self._export_basemap()
+
+            if not is_basemap_export_success and not self._is_canceled:
+                self.warning.emit(
+                    self.tr("Failed to create basemap"),
+                    self.tr("The basemap creation was unsuccessful."),
+                )
 
         # We store the pks of the original vector layers
         for layer_idx, layer in enumerate(project_layers):
@@ -270,6 +285,8 @@ def _convert(self, project: QgsProject) -> None:
                 self.trUtf8("Copying layers…"),
             )
 
+            self._check_canceled()
+
             if layer_action == SyncAction.OFFLINE:
                 offline_layers.append(layer)
                 self.__offline_layer_names.append(layer.name())
@@ -292,6 +309,8 @@ def _convert(self, project: QgsProject) -> None:
         # save the original project path
         self.project_configuration.original_project_path = str(self.original_filename)
 
+        self._check_canceled()
+
         # save the offline project twice so that the offline plugin can "know" that it's a relative path
         QgsProject.instance().write(str(export_project_filename))
 
@@ -306,6 +325,8 @@ def _convert(self, project: QgsProject) -> None:
             if not should_copy:
                 continue
 
+            self._check_canceled()
+
             copy_attachments(
                 self.original_filename.parent,
                 export_project_filename.parent,
@@ -315,6 +336,8 @@ def _convert(self, project: QgsProject) -> None:
         # copy project plugin if present
         plugin_file = Path("{}.qml".format(str(self.original_filename)[:-4]))
         if plugin_file.exists():
+            self._check_canceled()
+
             copy_multifile(
                 plugin_file, export_project_filename.parent.joinpath(plugin_file.name)
             )
@@ -328,6 +351,8 @@ def _convert(self, project: QgsProject) -> None:
                     QgsProject.instance(),
                 ).transformBoundingBox(self.area_of_interest.boundingBox())
 
+            self._check_canceled()
+
             is_success = self.offliner.convert_to_offline(
                 str(self._export_filename.with_name("data.gpkg")),
                 offline_layers,
@@ -342,10 +367,14 @@ def _convert(self, project: QgsProject) -> None:
                     )
                 )
 
+            self._check_canceled()
+
             # Disable project options that could create problems on a portable
             # project with offline layers
             self.post_process_offline_layers()
 
+        self._check_canceled()
+
         # Now we have a project state which can be saved as offline project
         on_original_project_write = self._on_original_project_write_wrapper(
             xml_elements_to_preserve
@@ -711,11 +740,18 @@ def _on_offline_editing_task_progress(self, progress):
 
     def cancel(self) -> None:
         """
-        Cancels the offline export of a QField project.
+        Cancels the offline packaging of a QField project.
         Typically used when the QField export dialog is closed.
         """
+        self._is_canceled = True
         self._feedback.cancel()
 
+    def _check_canceled(self) -> None:
+        """Checks if packaging has been and should be canceled."""
+        QCoreApplication.processEvents()
+        if self._is_canceled:
+            raise PackagingCanceledException()
+
     def convertorProcessingProgress(self):
         """
         Will create a new progress object for processing to get feedback from the basemap