Delay showing the download list in the UI until all checkpoints are l…

…oaded; show the number of the loaded checkpoints instead

src/tribler/core/components/libtorrent/download_manager/download_manager.py

@@ -104,6 +104,10 @@ def __init__(self,
 
         self.downloads = {}
 
+        self.checkpoints_count = None
+        self.checkpoints_loaded = 0
+        self.all_checkpoints_are_loaded = False
+
         self.metadata_tmpdir = None
         # Dictionary that maps infohashes to download instances. These include only downloads that have
         # been made specifically for fetching metainfo, and will be removed afterwards.
@@ -839,9 +843,13 @@ def get_last_download_states(self):
 
     async def load_checkpoints(self):
         self._logger.info("Load checkpoints...")
-        for filename in self.get_checkpoint_dir().glob('*.conf'):
+        checkpoint_filenames = list(self.get_checkpoint_dir().glob('*.conf'))
+        self.checkpoints_count = len(checkpoint_filenames)
+        for i, filename in enumerate(checkpoint_filenames, start=1):
             self.load_checkpoint(filename)
+            self.checkpoints_loaded = i
             await sleep(.01)
+        self.all_checkpoints_are_loaded = True
         self._logger.info("Checkpoints are loaded")
 
     def load_checkpoint(self, filename):

src/tribler/core/components/libtorrent/restapi/downloads_endpoint.py

@@ -84,7 +84,7 @@ class DownloadsEndpoint(RESTEndpoint):
     starting, pausing and stopping downloads.
     """
 
-    def __init__(self, download_manager, metadata_store=None, tunnel_community=None):
+    def __init__(self, download_manager: DownloadManager, metadata_store=None, tunnel_community=None):
         super().__init__()
         self.download_manager = download_manager
         self.mds = metadata_store
@@ -219,6 +219,11 @@ def get_files_info_json(download):
                         'vod_prebuffering_progress_consec': Float,
                         'error': String,
                         'time_added': Integer
+                    }),
+                    'checkpoints': schema(Checkpoints={
+                        'total': Integer,
+                        'loaded': Integer,
+                        'all_loaded': Boolean,
                     })
                 }),
             }
@@ -237,6 +242,15 @@ async def get_downloads(self, request):
         get_pieces = params.get('get_pieces', '0') == '1'
         get_files = params.get('get_files', '0') == '1'
 
+        checkpoints = {
+            "total": self.download_manager.checkpoints_count,
+            "loaded": self.download_manager.checkpoints_loaded,
+            "all_loaded": self.download_manager.all_checkpoints_are_loaded,
+        }
+
+        if not self.download_manager.all_checkpoints_are_loaded:
+            return RESTResponse({"downloads": [], "checkpoints": checkpoints})
+
         downloads_json = []
         downloads = self.download_manager.get_downloads()
         for download in downloads:
@@ -332,7 +346,7 @@ async def get_downloads(self, request):
                 download_json["files"] = self.get_files_info_json(download)
 
             downloads_json.append(download_json)
-        return RESTResponse({"downloads": downloads_json})
+        return RESTResponse({"downloads": downloads_json, "checkpoints": checkpoints})
 
     @docs(
         tags=["Libtorrent"],

src/tribler/core/components/libtorrent/restapi/tests/test_downloads_endpoint.py

@@ -149,22 +149,39 @@ def test_get_extended_status_circuits(mock_extended_status):
     assert mock_extended_status == DLSTATUS_CIRCUITS
 
 
+async def test_get_downloads_if_checkpoints_are_not_loaded(mock_dlmgr, rest_api):
+    mock_dlmgr.checkpoints_count = 10
+    mock_dlmgr.checkpoints_loaded = 5
+    mock_dlmgr.all_checkpoints_are_loaded = False
+
+    expected_json = {"downloads": [], "checkpoints": {"total": 10, "loaded": 5, "all_loaded": False}}
+    await do_request(rest_api, "downloads?get_peers=1&get_pieces=1", expected_code=200, expected_json=expected_json)
+
+
 async def test_get_downloads_no_downloads(mock_dlmgr, rest_api):
     """
     Testing whether the API returns an empty list when downloads are fetched but no downloads are active
     """
-    result = await do_request(rest_api, 'downloads?get_peers=1&get_pieces=1',
-                              expected_code=200, expected_json={"downloads": []})
-    assert result["downloads"] == []
+    mock_dlmgr.checkpoints_count = 0
+    mock_dlmgr.checkpoints_loaded = 0
+    mock_dlmgr.all_checkpoints_are_loaded = True
+
+    expected_json = {"downloads": [], "checkpoints": {"total": 0, "loaded": 0, "all_loaded": True}}
+    await do_request(rest_api, "downloads?get_peers=1&get_pieces=1", expected_code=200, expected_json=expected_json)
 
 
 async def test_get_downloads(mock_dlmgr, test_download, rest_api):
     """
     Testing whether the API returns the right download when a download is added
     """
     mock_dlmgr.get_downloads = lambda: [test_download]
+    mock_dlmgr.checkpoints_count = 1
+    mock_dlmgr.checkpoints_loaded = 1
+    mock_dlmgr.all_checkpoints_are_loaded = True
+
     downloads = await do_request(rest_api, 'downloads?get_peers=1&get_pieces=1', expected_code=200)
     assert len(downloads["downloads"]) == 1
+    assert downloads["checkpoints"] == {"total": 1, "loaded": 1, "all_loaded": True}
 
 
 async def test_start_download_no_uri(rest_api):

src/tribler/core/components/libtorrent/tests/test_download_manager.py

@@ -1,3 +1,4 @@
+import asyncio
 from asyncio import Future, gather, get_event_loop, sleep
 from unittest.mock import MagicMock
 
@@ -381,6 +382,13 @@ def mock_start_download(*_, **__):
     assert not good
 
 
+@pytest.mark.asyncio
+async def test_download_manager_start(fake_dlmgr):
+    fake_dlmgr.start()
+    await asyncio.sleep(0.01)
+    assert fake_dlmgr.all_checkpoints_are_loaded
+
+
 def test_load_empty_checkpoint(fake_dlmgr, tmpdir):
     """
     Test whether download resumes with faulty pstate file.
@@ -413,8 +421,16 @@ def mocked_load_checkpoint(filename):
         state_file.write(b"hi")
 
     fake_dlmgr.load_checkpoint = mocked_load_checkpoint
+    assert fake_dlmgr.all_checkpoints_are_loaded is False
+    assert fake_dlmgr.checkpoints_count is None
+    assert fake_dlmgr.checkpoints_loaded == 0
+
     await fake_dlmgr.load_checkpoints()
+
     assert mocked_load_checkpoint.called
+    assert fake_dlmgr.all_checkpoints_are_loaded is True
+    assert fake_dlmgr.checkpoints_count == 1
+    assert fake_dlmgr.checkpoints_loaded == 1
 
 
 @pytest.mark.asyncio

src/tribler/core/conftest.py

@@ -96,6 +96,9 @@ def mock_dlmgr(state_dir):
     dlmgr.get_checkpoint_dir = lambda: checkpoints_dir
     dlmgr.state_dir = state_dir
     dlmgr.get_downloads = lambda: []
+    dlmgr.checkpoints_count = 1
+    dlmgr.checkpoints_loaded = 1
+    dlmgr.all_checkpoints_are_loaded = True
     return dlmgr
 
 

src/tribler/gui/widgets/downloadspage.py

@@ -1,5 +1,7 @@
+import logging
 import os
 import time
+from typing import Optional
 
 from PyQt5.QtCore import QTimer, QUrl, Qt, pyqtSignal
 from PyQt5.QtGui import QDesktopServices
@@ -53,6 +55,7 @@ class DownloadsPage(AddBreadcrumbOnShowMixin, QWidget):
 
     def __init__(self):
         QWidget.__init__(self)
+        self._logger = logging.getLogger(self.__class__.__name__)
         self.export_dir = None
         self.filter = DOWNLOADS_FILTER_ALL
         self.download_widgets = {}  # key: infohash, value: QTreeWidgetItem
@@ -62,7 +65,8 @@ def __init__(self):
         self.downloads_last_update = 0
         self.selected_items = []
         self.dialog = None
-        self.loading_message_widget = None
+        self.loading_message_widget: Optional[LoadingDownloadWidgetItem] = None
+        self.loading_list_item: Optional[LoadingListItem] = None
         self.total_download = 0
         self.total_upload = 0
 
@@ -109,10 +113,9 @@ def on_filter_text_changed(self, text):
     def start_loading_downloads(self):
         self.window().downloads_list.setSelectionMode(QAbstractItemView.NoSelection)
         self.loading_message_widget = LoadingDownloadWidgetItem()
+        self.loading_list_item = LoadingListItem(self.window().downloads_list)
         self.window().downloads_list.addTopLevelItem(self.loading_message_widget)
-        self.window().downloads_list.setItemWidget(
-            self.loading_message_widget, 2, LoadingListItem(self.window().downloads_list)
-        )
+        self.window().downloads_list.setItemWidget(self.loading_message_widget, 2, self.loading_list_item)
         self.schedule_downloads_timer(now=True)
 
     def schedule_downloads_timer(self, now=False):
@@ -148,6 +151,20 @@ def load_downloads(self):
     def on_received_downloads(self, downloads):
         if not downloads or "downloads" not in downloads:
             return  # This might happen when closing Tribler
+
+        checkpoints = downloads.get('checkpoints', {})
+        if checkpoints and self.loading_message_widget:
+            # If not all checkpoints are loaded, display the number of the loaded checkpoints
+            total = checkpoints['total']
+            loaded = checkpoints['loaded']
+            if not checkpoints['all_loaded']:
+                # The column is too narrow for a long message, probably we should redesign this UI element later
+                message = f'{loaded}/{total} checkpoints'
+                self._logger.info(f'Loading checkpoints: {message}')
+                self.loading_list_item.textlabel.setText(message)
+                self.schedule_downloads_timer()
+                return
+
         loading_widget_index = self.window().downloads_list.indexOfTopLevelItem(self.loading_message_widget)
         if loading_widget_index > -1:
             self.window().downloads_list.takeTopLevelItem(loading_widget_index)