very new files are not removed

this makes download_http more reliable when reusing a file that could otherwise have been removed by UnusedCleaner

larigira/unused.py

@@ -7,6 +7,8 @@ This component will look for files to be removed. There are some assumptions:
 import logging
 import os
 from os.path import normpath
+from pathlib import Path
+import time
 
 import mpd
 
@@ -30,6 +32,10 @@ except ImportError:
 
 
 class UnusedCleaner:
+    # ONLY_DELETE_OLDER_THAN is expressed in seconds.
+    # It configures the maximum age a file can have before being removed.
+    # Set it to "None" if you want to disable this feature.
+    ONLY_DELETE_OLDER_THAN = 30
     def __init__(self, conf):
         self.conf = conf
         self.waiting_removal_files = set()
@@ -69,7 +75,19 @@ class UnusedCleaner:
             for song in mpdc.playlistid()
             if song["file"].startswith("/")
         }
+        now = time.time()
         for fpath in self.waiting_removal_files - files_in_playlist:
+
+            # audio files are sometimes reused, as in download_http. To avoid
+            # referencing a file that UnusedCleaner is going to remove, users
+            # are invited to touch the file, so that UnusedCleaner doesn't
+            # consider it for removal. While this doesn't conceptually solve
+            # the race condition, it should now be extremely rare.
+
+            if ONLY_DELETE_OLDER_THAN is not None:
+                mtime = Path(fpath).stat().st_mtime
+                if now - mtime < ONLY_DELETE_OLDER_THAN:
+                    continue
             # we can remove it!
             self.log.debug("removing unused: %s", fpath)
             self.waiting_removal_files.remove(fpath)