Cleaning Up Extensions When Local Content Removed

chrome/browser/extensions/extension_garbage_collector.cc

+// 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.
+
+#include "chrome/browser/extensions/extension_garbage_collector.h"
+
+#include <map>
+#include <string>
+
+#include "base/bind.h"
+#include "base/file_util.h"
+#include "base/logging.h"
+#include "chrome/browser/extensions/extension_prefs.h"
+#include "chrome/browser/extensions/extension_service.h"
+#include "chrome/browser/prefs/pref_service.h"
+#include "chrome/common/extensions/extension_file_util.h"
+#include "content/public/browser/browser_thread.h"
+
+namespace extensions {
+
+ExtensionGarbageCollector::ExtensionGarbageCollector(
+    ExtensionService* extension_service)
+    : extension_service_(extension_service) {
+}
+
+ExtensionGarbageCollector::~ExtensionGarbageCollector() {
+}
+
+void ExtensionGarbageCollector::GarbageCollectExtensions() {
+  CHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
+
+  FilePath install_directory = extension_service_->install_directory();
+
+  // NOTE: It's important to use the file thread here because when the
+  // ExtensionService installs an extension, it begins on the file thread, and
+  // there are ordering dependencies between all of the extension-file-
+  // management tasks. If we do not follow the same thread pattern as the
+  // ExtensionService, then a race condition develops.
+  content::BrowserThread::PostTask(
+      content::BrowserThread::FILE, FROM_HERE,
+      base::Bind(
+           &ExtensionGarbageCollector::
+               CheckExtensionDirectoriesOnBackgroundThread,
+           base::Unretained(this),
+           install_directory));
+}
+
+void ExtensionGarbageCollector::CheckExtensionDirectoriesOnBackgroundThread(
+    const FilePath& install_directory) {
+  CHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::FILE));
+
+  DVLOG(1) << "Garbage collecting extensions...";
+
+  if (!file_util::DirectoryExists(install_directory))
+    return;
+
+  std::set<FilePath> extension_paths;
+
+  file_util::FileEnumerator enumerator(install_directory,
+                                       false,  // Not recursive.
+                                       file_util::FileEnumerator::DIRECTORIES);
+
+  for (FilePath extension_path = enumerator.Next(); !extension_path.empty();
+       extension_path = enumerator.Next()) {
+    std::string extension_id = extension_path.BaseName().MaybeAsASCII();
+    if (!Extension::IdIsValid(extension_id))
+      extension_id.clear();
+
+    // Delete directories that aren't valid IDs.
+    if (extension_id.empty()) {
+      DVLOG(1) << "Deleting invalid extension directory "
+               << extension_path.value() << ".";
+      file_util::Delete(extension_path, true);  // Recursive.
+      continue;
+    }
+
+    extension_paths.insert(extension_path);
+  }
+
+  content::BrowserThread::PostTask(
+      content::BrowserThread::UI, FROM_HERE,
+      base::Bind(
+           &ExtensionGarbageCollector::CheckExtensionPreferences,
+           base::Unretained(this),
+           extension_paths));
+}
+
+void ExtensionGarbageCollector::CheckExtensionPreferences(
+    const std::set<FilePath>& extension_paths) {
+  CHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
+
+  ExtensionPrefs* extension_prefs = extension_service_->extension_prefs();
+
+  if (extension_prefs->pref_service()->ReadOnly())
+    return;
+
+  scoped_ptr<ExtensionPrefs::ExtensionsInfo> info(
+      extension_prefs->GetInstalledExtensionsInfo());
+
+  std::map<std::string, FilePath> extension_pref_paths;
+  for (size_t i = 0; i < info->size(); ++i) {
+    extension_pref_paths[info->at(i)->extension_id] =
+        info->at(i)->extension_path;
+  }
+
+  std::set<std::string> extension_ids;
+
+  // Check each directory for a reference in the preferences.
+  for (std::set<FilePath>::const_iterator path = extension_paths.begin();
+       path != extension_paths.end();
+       ++path) {
+    std::string extension_id;
+    extension_id = path->BaseName().MaybeAsASCII();
+    if (extension_id.empty())
+      continue;
+
+    extension_ids.insert(extension_id);
+
+    std::map<std::string, FilePath>::const_iterator iter =
+        extension_pref_paths.find(extension_id);
+
+    if (iter == extension_pref_paths.end()) {
+      DVLOG(1) << "Deleting unreferenced install for directory "
+               << path->LossyDisplayName() << ".";
+      content::BrowserThread::PostTask(
+          content::BrowserThread::FILE, FROM_HERE,
+          base::Bind(
+              &extension_file_util::DeleteFile,
+              *path,
+              true));  // recursive.
+      continue;
+    }
+
+    // Clean up old version directories.
+    content::BrowserThread::PostTask(
+        content::BrowserThread::FILE, FROM_HERE,
+        base::Bind(
+             &ExtensionGarbageCollector::CleanupOldVersionsOnBackgroundThread,
+             base::Unretained(this), *path, iter->second.BaseName()));
+  }
+
+  // Check each entry in the preferences for an existing path.
+  for (std::map<std::string, FilePath>::const_iterator extension =
+           extension_pref_paths.begin();
+       extension != extension_pref_paths.end();
+       ++extension) {
+    std::set<std::string>::const_iterator iter = extension_ids.find(
+        extension->first);
+
+    if (iter != extension_ids.end())
+      continue;
+
+    std::string extension_id = extension->first;
+
+    DVLOG(1) << "Could not access local content for extension with id "
+             << extension_id << "; uninstalling extension.";
+
+    // If the extension failed to load fully (e.g. the user deleted an unpacked
+    // extension's manifest or the manifest points to the wrong path), we cannot
+    // use UninstallExtension, which relies on a valid Extension object.
+    if (!extension_service_->GetInstalledExtension(extension_id)) {
+      scoped_ptr<ExtensionInfo> info(extension_service_->extension_prefs()
+          ->GetInstalledExtensionInfo(extension_id));
+      extension_service_->extension_prefs()->OnExtensionUninstalled(
+          extension_id, info->extension_location, false);
+    } else {
+      extension_service_->UninstallExtension(extension_id, false, NULL);
+    }
+  }
+}
+
+void ExtensionGarbageCollector::CleanupOldVersionsOnBackgroundThread(
+    const FilePath& path,
+    const FilePath& current_version) {
+  CHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::FILE));
+  file_util::FileEnumerator versions_enumerator(
+      path,
+      false,  // Not recursive.
+      file_util::FileEnumerator::DIRECTORIES);
+  for (FilePath version_dir = versions_enumerator.Next();
+       !version_dir.value().empty();
+       version_dir = versions_enumerator.Next()) {
+    if (version_dir.BaseName() != current_version) {
+      DVLOG(1) << "Deleting old version for directory "
+               << version_dir.LossyDisplayName() << ".";
+      if (!file_util::Delete(version_dir, true))  // Recursive.
+        NOTREACHED();
+    }
+  }
+}
+
+}  // namespace extensions