Bug 1788986 - Part 2: Use a background task for QM shutdown cleanup r=janv,smaug

Differential Revision: https://phabricator.services.mozilla.com/D156331

modules/libpref/init/StaticPrefList.yaml

@@ -3431,6 +3431,14 @@
   value: 200
   mirror: always
 
+#ifdef MOZ_BACKGROUNDTASKS
+# Use a Background Task to delete files at shutdown.
+- name: dom.quotaManager.backgroundTask.enabled
+  type: bool
+  value: @IS_NIGHTLY_BUILD@
+  mirror: never
+#endif
+
 # Determines within what distance of a tick mark, in pixels, dragging an input
 # range range will snap the range's value to that tick mark. By default, this is
 # half the default width of the range thumb.

toolkit/components/cleardata/ClearDataService.sys.mjs

@@ -739,11 +739,29 @@ const QuotaCleaner = {
   async cleanupAfterDeletionAtShutdown() {
     const storageDir = PathUtils.join(
       PathUtils.profileDir,
-      Services.prefs.getStringPref("dom.quotaManager.storageName"),
-      "to-be-removed"
+      Services.prefs.getStringPref("dom.quotaManager.storageName")
     );
 
-    await IOUtils.remove(storageDir, { recursive: true });
+    if (
+      !AppConstants.MOZ_BACKGROUNDTASKS ||
+      !Services.prefs.getBoolPref("dom.quotaManager.backgroundTask.enabled")
+    ) {
+      await IOUtils.remove(PathUtils.join(storageDir, "to-be-removed"), {
+        recursive: true,
+      });
+      return;
+    }
+
+    const runner = Cc["@mozilla.org/backgroundtasksrunner;1"].getService(
+      Ci.nsIBackgroundTasksRunner
+    );
+
+    runner.removeDirectoryInDetachedProcess(
+      storageDir,
+      "to-be-removed",
+      "0",
+      ""
+    );
   },
 };
 

toolkit/components/cleardata/tests/marionette/test_moved_origin_directory_cleanup.py

@@ -15,6 +15,7 @@ class MovedOriginDirectoryCleanupTestCase(MarionetteTestCase):
             {
                 "privacy.sanitize.sanitizeOnShutdown": True,
                 "privacy.clearOnShutdown.offlineApps": True,
+                "dom.quotaManager.backgroundTask.enabled": False,
             }
         )
         self.moved_origin_directory = (
@@ -58,3 +59,19 @@ class MovedOriginDirectoryCleanupTestCase(MarionetteTestCase):
             lambda _: not self.moved_origin_directory.exists(),
             message="to-be-removed subdirectory must disappear",
         )
+
+    def test_ensure_cleanup_by_quit_with_background_task(self):
+        self.assertTrue(
+            self.moved_origin_directory.exists(),
+            "to-be-removed subdirectory must exist",
+        )
+
+        self.marionette.set_pref("dom.quotaManager.backgroundTask.enabled", True)
+
+        # Cleanup happens via Sanitizer.sanitizeOnShutdown
+        self.marionette.quit()
+
+        Wait(self.marionette).until(
+            lambda _: not self.moved_origin_directory.exists(),
+            message="to-be-removed subdirectory must disappear",
+        )

toolkit/components/cleardata/tests/unit/test_quota.js

@@ -18,6 +18,11 @@ const skipLocalStorageTests = Services.prefs.getBoolPref(
   "dom.storage.enable_unsupported_legacy_implementation"
 );
 
+// XXX(krosylight): xpcshell does not support background tasks
+const skipCleanupAfterDeletionAtShutdownTests = Services.prefs.getBoolPref(
+  "dom.quotaManager.backgroundTask.enabled"
+);
+
 /**
  * Create an origin with partitionKey.
  * @param {String} host - Host portion of origin to create.
@@ -535,6 +540,11 @@ add_task(async function test_deleteAllAtShutdown() {
     `storage/to-be-removed has ${TEST_ORIGINS.length} subdirectories`
   );
 
+  if (skipCleanupAfterDeletionAtShutdownTests) {
+    // XXX(krosylight): xpcshell does not support background tasks
+    return;
+  }
+
   info("Verifying cleanupAfterDeletionAtShutdown");
   await new Promise(aResolve => {
     Services.clearData.cleanupAfterDeletionAtShutdown(