Refactor loading out of ExtensionService.

chrome/browser/extensions/installed_extension_loader.cc

+// Copyright (c) 2011 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/installed_extension_loader.h"
+
+#include "base/file_path.h"
+#include "base/metrics/histogram.h"
+#include "base/stringprintf.h"
+#include "base/utf_string_conversions.h"
+#include "base/values.h"
+#include "chrome/browser/extensions/extension_prefs.h"
+#include "chrome/browser/extensions/extension_service.h"
+#include "chrome/common/chrome_switches.h"
+#include "chrome/common/extensions/extension.h"
+#include "chrome/common/extensions/extension_file_util.h"
+#include "chrome/common/extensions/extension_l10n_util.h"
+#include "chrome/common/pref_names.h"
+#include "content/public/browser/notification_service.h"
+#include "content/browser/user_metrics.h"
+
+namespace errors = extension_manifest_errors;
+
+namespace {
+
+// The following enumeration is used in histograms matching
+// Extensions.ManifestReload* .  Values may be added, as long as existing
+// values are not changed.
+enum ManifestReloadReason {
+  NOT_NEEDED = 0,  // Reload not needed.
+  UNPACKED_DIR,  // Unpacked directory.
+  NEEDS_RELOCALIZATION,  // The locale has changed since we read this extension.
+  NUM_MANIFEST_RELOAD_REASONS
+};
+
+ManifestReloadReason ShouldReloadExtensionManifest(const ExtensionInfo& info) {
+  // Always reload manifests of unpacked extensions, because they can change
+  // on disk independent of the manifest in our prefs.
+  if (info.extension_location == Extension::LOAD)
+    return UNPACKED_DIR;
+
+  // Reload the manifest if it needs to be relocalized.
+  if (extension_l10n_util::ShouldRelocalizeManifest(info))
+    return NEEDS_RELOCALIZATION;
+
+  return NOT_NEEDED;
+}
+
+}  // namespace
+
+namespace extensions {
+
+InstalledExtensionLoader::InstalledExtensionLoader(
+    ExtensionService* extension_service,
+    ExtensionPrefs* extension_prefs)
+    : extension_service_(extension_service),
+      extension_prefs_(extension_prefs) {
+}
+
+InstalledExtensionLoader::~InstalledExtensionLoader() {
+}
+
+void InstalledExtensionLoader::Load(const ExtensionInfo& info,
+                                    bool write_to_prefs) {
+  std::string error;
+  scoped_refptr<const Extension> extension(NULL);
+  if (!extension_prefs_->IsExtensionAllowedByPolicy(info.extension_id)) {
+    error = errors::kDisabledByPolicy;
+  } else if (info.extension_manifest.get()) {
+    extension = Extension::Create(
+        info.extension_path,
+        info.extension_location,
+        *info.extension_manifest,
+        GetCreationFlags(&info),
+        &error);
+  } else {
+    error = errors::kManifestUnreadable;
+  }
+
+  // Once installed, non-unpacked extensions cannot change their IDs (e.g., by
+  // updating the 'key' field in their manifest).
+  if (extension &&
+      extension->location() != Extension::LOAD &&
+      info.extension_id != extension->id()) {
+    error = errors::kCannotChangeExtensionID;
+    extension = NULL;
+    UserMetrics::RecordAction(UserMetricsAction("Extensions.IDChangedError"));
+  }
+
+  if (!extension) {
+    // TODO(aa): Remove ReportExtensionLoadError. It doesn't do enough to be
+    // worth the dependency on ES.
+    extension_service_->
+        ReportExtensionLoadError(info.extension_path, error, false);
+    return;
+  }
+
+  if (write_to_prefs)
+    extension_prefs_->UpdateManifest(extension);
+
+  extension_service_->AddExtension(extension);
+}
+
+void InstalledExtensionLoader::LoadAllExtensions() {
+  CHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+
+  base::TimeTicks start_time = base::TimeTicks::Now();
+
+  scoped_ptr<ExtensionPrefs::ExtensionsInfo> extensions_info(
+      extension_prefs_->GetInstalledExtensionsInfo());
+
+  std::vector<int> reload_reason_counts(NUM_MANIFEST_RELOAD_REASONS, 0);
+  bool should_write_prefs = false;
+
+  for (size_t i = 0; i < extensions_info->size(); ++i) {
+    ExtensionInfo* info = extensions_info->at(i).get();
+
+    ManifestReloadReason reload_reason = ShouldReloadExtensionManifest(*info);
+    ++reload_reason_counts[reload_reason];
+    UMA_HISTOGRAM_ENUMERATION("Extensions.ManifestReloadEnumValue",
+                              reload_reason, 100);
+
+    if (reload_reason != NOT_NEEDED) {
+      // Reloading an extension reads files from disk.  We do this on the
+      // UI thread because reloads should be very rare, and the complexity
+      // added by delaying the time when the extensions service knows about
+      // all extensions is significant.  See crbug.com/37548 for details.
+      // |allow_io| disables tests that file operations run on the file
+      // thread.
+      base::ThreadRestrictions::ScopedAllowIO allow_io;
+
+      std::string error;
+      scoped_refptr<const Extension> extension(
+          extension_file_util::LoadExtension(
+              info->extension_path,
+              info->extension_location,
+              GetCreationFlags(info),
+              &error));
+
+      if (extension.get()) {
+        extensions_info->at(i)->extension_manifest.reset(
+            static_cast<DictionaryValue*>(
+                extension->manifest_value()->DeepCopy()));
+        should_write_prefs = true;
+      }
+    }
+  }
+
+  for (size_t i = 0; i < extensions_info->size(); ++i) {
+    Load(*extensions_info->at(i), should_write_prefs);
+  }
+
+  extension_service_->OnLoadedInstalledExtensions();
+
+  // The histograms Extensions.ManifestReload* allow us to validate
+  // the assumption that reloading manifest is a rare event.
+  UMA_HISTOGRAM_COUNTS_100("Extensions.ManifestReloadNotNeeded",
+                           reload_reason_counts[NOT_NEEDED]);
+  UMA_HISTOGRAM_COUNTS_100("Extensions.ManifestReloadUnpackedDir",
+                           reload_reason_counts[UNPACKED_DIR]);
+  UMA_HISTOGRAM_COUNTS_100("Extensions.ManifestReloadNeedsRelocalization",
+                           reload_reason_counts[NEEDS_RELOCALIZATION]);
+
+  UMA_HISTOGRAM_COUNTS_100("Extensions.LoadAll",
+                           extension_service_->extensions()->size());
+  UMA_HISTOGRAM_COUNTS_100("Extensions.Disabled",
+                           extension_service_->disabled_extensions()->size());
+
+  UMA_HISTOGRAM_TIMES("Extensions.LoadAllTime",
+                      base::TimeTicks::Now() - start_time);
+
+  int app_user_count = 0;
+  int app_external_count = 0;
+  int hosted_app_count = 0;
+  int packaged_app_count = 0;
+  int user_script_count = 0;
+  int extension_user_count = 0;
+  int extension_external_count = 0;
+  int theme_count = 0;
+  int page_action_count = 0;
+  int browser_action_count = 0;
+  const ExtensionList* extensions = extension_service_->extensions();
+  ExtensionList::const_iterator ex;
+  for (ex = extensions->begin(); ex != extensions->end(); ++ex) {
+    Extension::Location location = (*ex)->location();
+    Extension::Type type = (*ex)->GetType();
+    if ((*ex)->is_app()) {
+      UMA_HISTOGRAM_ENUMERATION("Extensions.AppLocation",
+                                location, 100);
+    } else if (type == Extension::TYPE_EXTENSION) {
+      UMA_HISTOGRAM_ENUMERATION("Extensions.ExtensionLocation",
+                                location, 100);
+    }
+
+    // Don't count component extensions, since they are only extensions as an
+    // implementation detail.
+    if (location == Extension::COMPONENT)
+      continue;
+
+    // Don't count unpacked extensions, since they're a developer-specific
+    // feature.
+    if (location == Extension::LOAD)
+      continue;
+
+    // Using an enumeration shows us the total installed ratio across all users.
+    // Using the totals per user at each startup tells us the distribution of
+    // usage for each user (e.g. 40% of users have at least one app installed).
+    UMA_HISTOGRAM_ENUMERATION("Extensions.LoadType", type, 100);
+    switch (type) {
+      case Extension::TYPE_THEME:
+        ++theme_count;
+        break;
+      case Extension::TYPE_USER_SCRIPT:
+        ++user_script_count;
+        break;
+      case Extension::TYPE_HOSTED_APP:
+        ++hosted_app_count;
+        if (Extension::IsExternalLocation(location)) {
+          ++app_external_count;
+        } else {
+          ++app_user_count;
+        }
+        break;
+      case Extension::TYPE_PACKAGED_APP:
+        ++packaged_app_count;
+        if (Extension::IsExternalLocation(location)) {
+          ++app_external_count;
+        } else {
+          ++app_user_count;
+        }
+        break;
+      case Extension::TYPE_EXTENSION:
+      default:
+        if (Extension::IsExternalLocation(location)) {
+          ++extension_external_count;
+        } else {
+          ++extension_user_count;
+        }
+        break;
+    }
+    if ((*ex)->page_action() != NULL)
+      ++page_action_count;
+    if ((*ex)->browser_action() != NULL)
+      ++browser_action_count;
+
+    extension_service_->RecordPermissionMessagesHistogram(
+        ex->get(), "Extensions.Permissions_Load");
+  }
+  UMA_HISTOGRAM_COUNTS_100("Extensions.LoadApp",
+                           app_user_count + app_external_count);
+  UMA_HISTOGRAM_COUNTS_100("Extensions.LoadAppUser", app_user_count);
+  UMA_HISTOGRAM_COUNTS_100("Extensions.LoadAppExternal", app_external_count);
+  UMA_HISTOGRAM_COUNTS_100("Extensions.LoadHostedApp", hosted_app_count);
+  UMA_HISTOGRAM_COUNTS_100("Extensions.LoadPackagedApp", packaged_app_count);
+  UMA_HISTOGRAM_COUNTS_100("Extensions.LoadExtension",
+                           extension_user_count + extension_external_count);
+  UMA_HISTOGRAM_COUNTS_100("Extensions.LoadExtensionUser",
+                           extension_user_count);
+  UMA_HISTOGRAM_COUNTS_100("Extensions.LoadExtensionExternal",
+                           extension_external_count);
+  UMA_HISTOGRAM_COUNTS_100("Extensions.LoadUserScript", user_script_count);
+  UMA_HISTOGRAM_COUNTS_100("Extensions.LoadTheme", theme_count);
+  UMA_HISTOGRAM_COUNTS_100("Extensions.LoadPageAction", page_action_count);
+  UMA_HISTOGRAM_COUNTS_100("Extensions.LoadBrowserAction",
+                           browser_action_count);
+}
+
+int InstalledExtensionLoader::GetCreationFlags(const ExtensionInfo* info) {
+  int flags = Extension::NO_FLAGS;
+  if (info->extension_location != Extension::LOAD)
+    flags |= Extension::REQUIRE_KEY;
+  if (Extension::ShouldDoStrictErrorChecking(info->extension_location))
+    flags |= Extension::STRICT_ERROR_CHECKS;
+  if (extension_prefs_->AllowFileAccess(info->extension_id))
+    flags |= Extension::ALLOW_FILE_ACCESS;
+  if (extension_prefs_->IsFromWebStore(info->extension_id))
+    flags |= Extension::FROM_WEBSTORE;
+  if (extension_prefs_->IsFromBookmark(info->extension_id))
+    flags |= Extension::FROM_BOOKMARK;
+  return flags;
+}
+
+}  // namespace extensions