Cleaning Up Extensions When Local Content Removed

chrome/browser/extensions/extension_garbage_collector.h

+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_BROWSER_EXTENSIONS_EXTENSION_GARBAGE_COLLECTOR_H_
+#define CHROME_BROWSER_EXTENSIONS_EXTENSION_GARBAGE_COLLECTOR_H_
+#pragma once
+
+#include <set>
+
+#include "base/file_path.h"
+#include "base/memory/ref_counted.h"
+
+class ExtensionService;
+
+// Garbage collection for extensions. This will delete any directories in the
+// installation directory of |extension_service_| that aren't valid, as well
+// as removing any references in the preferences to extensions that are
+// missing local content.
+class ExtensionGarbageCollector
+    : public base::RefCountedThreadSafe<ExtensionGarbageCollector> {
+ public:
+  explicit ExtensionGarbageCollector(ExtensionService* extension_service);
+  virtual ~ExtensionGarbageCollector();
+
+  // Begin garbage collection; fetch the installed extensions' ids.
+  void GarbageCollectExtensions();
+
+ private:
+  // Check the installation directory for directories with invalid extension
+  // ids, deleting them if found. Call CheckExtensionPreferences with a list of
+  // present directories.
+  void CheckExtensionDirectoriesOnBackgroundThread(
+      const FilePath& installation_directory);
+
+  // Check for any extension directories which:
+  //   - Are an old version of a current extension;
+  //   - Are present in the preferences but not on the file system;
+  //   - Are present on the file system, but not in the preferences
+  // and delete them if found.
+  void CheckExtensionPreferences(const std::set<FilePath>& extension_paths);
+
+  // Helper function to cleanup any old versions of an extension in the
+  // extension's base directory.
+  void CleanupOldVersionsOnBackgroundThread(
+      const FilePath& path, const FilePath& current_version);
+
+  ExtensionService* extension_service_;
+};
+
+#endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_GARBAGE_COLLECTOR_H_