Don't crash when trying to create an ExtensionSyncData from invalid SyncData.

chrome/browser/extensions/extension_sync_data.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_sync_data.h"
 
 #include "base/logging.h"
+#include "base/metrics/histogram_macros.h"
 #include "base/strings/stringprintf.h"
 #include "chrome/browser/extensions/app_sync_data.h"
 #include "chrome/browser/extensions/extension_service.h"
 #include "components/crx_file/id_util.h"
 #include "extensions/common/extension.h"
 #include "extensions/common/manifest_url_handlers.h"
 #include "sync/api/sync_data.h"
 #include "sync/protocol/extension_specifics.pb.h"
 #include "sync/protocol/sync.pb.h"
 
 namespace extensions {
 
 namespace {
 
 std::string GetExtensionSpecificsLogMessage(
     const sync_pb::ExtensionSpecifics& specifics) {
   return base::StringPrintf("id: %s\nversion: %s\nupdate_url: %s",
                             specifics.id().c_str(),
                             specifics.version().c_str(),
                             specifics.update_url().c_str());
 }
 
+enum BadSyncDataReason {
+  // Invalid extension ID.
+  BAD_EXTENSION_ID,
+
+  // Invalid version.
+  BAD_VERSION,
+
+  // Invalid update URL.
+  BAD_UPDATE_URL,
+
+  // No ExtensionSpecifics in the EntitySpecifics.
+  NO_EXTENSION_SPECIFICS,
+
+  // Must be at the end.
+  NUM_BAD_SYNC_DATA_REASONS
+};
+
+void RecordBadSyncData(BadSyncDataReason reason) {
+  UMA_HISTOGRAM_ENUMERATION("Extensions.BadSyncDataReason", reason,
+                            NUM_BAD_SYNC_DATA_REASONS);
+}
+
 }  // namespace
 
 ExtensionSyncData::ExtensionSyncData()
     : uninstalled_(false),
       enabled_(false),
       incognito_enabled_(false),
       remote_install_(false),
       all_urls_enabled_(BOOLEAN_UNSET),
       installed_by_custodian_(false) {
 }
 
-ExtensionSyncData::ExtensionSyncData(const syncer::SyncData& sync_data)
-    : uninstalled_(false),
-      enabled_(false),
-      incognito_enabled_(false),
-      remote_install_(false),
-      all_urls_enabled_(BOOLEAN_UNSET),
-      installed_by_custodian_(false) {
-  PopulateFromSyncData(sync_data);
-}
-
-ExtensionSyncData::ExtensionSyncData(const syncer::SyncChange& sync_change)
-    : uninstalled_(sync_change.change_type() ==
-                   syncer::SyncChange::ACTION_DELETE),
-      enabled_(false),
-      incognito_enabled_(false),
-      remote_install_(false),
-      all_urls_enabled_(BOOLEAN_UNSET),
-      installed_by_custodian_(false) {
-  PopulateFromSyncData(sync_change.sync_data());
-}
-
 ExtensionSyncData::ExtensionSyncData(const Extension& extension,
                                      bool enabled,
                                      bool incognito_enabled,
                                      bool remote_install,
                                      OptionalBoolean all_urls_enabled)
     : id_(extension.id()),
       uninstalled_(false),
       enabled_(enabled),
       incognito_enabled_(incognito_enabled),
       remote_install_(remote_install),
       all_urls_enabled_(all_urls_enabled),
       installed_by_custodian_(extension.was_installed_by_custodian()),
       version_(extension.from_bookmark() ? base::Version("0")
                                          : *extension.version()),
       update_url_(ManifestURL::GetUpdateURL(&extension)),
       name_(extension.non_localized_name()) {
 }
 
 ExtensionSyncData::~ExtensionSyncData() {}
 
+// static
+scoped_ptr<ExtensionSyncData> ExtensionSyncData::CreateFromSyncData(
+    const syncer::SyncData& sync_data) {
+  scoped_ptr<ExtensionSyncData> data(new ExtensionSyncData);
+  if (data->PopulateFromSyncData(sync_data))
+    return data.Pass();
+  return scoped_ptr<ExtensionSyncData>();
+}
+
+// static
+scoped_ptr<ExtensionSyncData> ExtensionSyncData::CreateFromSyncChange(
+    const syncer::SyncChange& sync_change) {
+  scoped_ptr<ExtensionSyncData> data(
+      CreateFromSyncData(sync_change.sync_data()));
+  if (!data.get())
+    return scoped_ptr<ExtensionSyncData>();
+
+  data->set_uninstalled(sync_change.change_type() ==
+                        syncer::SyncChange::ACTION_DELETE);
+  return data.Pass();
+}
+
 syncer::SyncData ExtensionSyncData::GetSyncData() const {
   sync_pb::EntitySpecifics specifics;
   PopulateExtensionSpecifics(specifics.mutable_extension());
 
   return syncer::SyncData::CreateLocalData(id_, name_, specifics);
 }
 
 syncer::SyncChange ExtensionSyncData::GetSyncChange(
     syncer::SyncChange::SyncChangeType change_type) const {
   return syncer::SyncChange(FROM_HERE, change_type, GetSyncData());
 }
 
 void ExtensionSyncData::PopulateExtensionSpecifics(
     sync_pb::ExtensionSpecifics* specifics) const {
   DCHECK(crx_file::id_util::IdIsValid(id_));
   specifics->set_id(id_);
   specifics->set_update_url(update_url_.spec());
   specifics->set_version(version_.GetString());
   specifics->set_enabled(enabled_);
   specifics->set_incognito_enabled(incognito_enabled_);
   specifics->set_remote_install(remote_install_);
   if (all_urls_enabled_ != BOOLEAN_UNSET)
     specifics->set_all_urls_enabled(all_urls_enabled_ == BOOLEAN_TRUE);
   specifics->set_installed_by_custodian(installed_by_custodian_);
   specifics->set_name(name_);
 }
 
-void ExtensionSyncData::PopulateFromExtensionSpecifics(
+bool ExtensionSyncData::PopulateFromExtensionSpecifics(
     const sync_pb::ExtensionSpecifics& specifics) {
   if (!crx_file::id_util::IdIsValid(specifics.id())) {
-    LOG(FATAL) << "Attempt to sync bad ExtensionSpecifics (bad ID):\n"
+    LOG(ERROR) << "Attempt to sync bad ExtensionSpecifics (bad ID):\n"
                << GetExtensionSpecificsLogMessage(specifics);
+    RecordBadSyncData(BAD_EXTENSION_ID);
+    return false;
   }
 
   Version specifics_version(specifics.version());
   if (!specifics_version.IsValid()) {
-    LOG(FATAL) << "Attempt to sync bad ExtensionSpecifics (bad version):\n"
+    LOG(ERROR) << "Attempt to sync bad ExtensionSpecifics (bad version):\n"
                << GetExtensionSpecificsLogMessage(specifics);
+    RecordBadSyncData(BAD_VERSION);
+    return false;
   }
 
   // The update URL must be either empty or valid.
   GURL specifics_update_url(specifics.update_url());
   if (!specifics_update_url.is_empty() && !specifics_update_url.is_valid()) {
-    LOG(FATAL) << "Attempt to sync bad ExtensionSpecifics (bad update URL):\n"
+    LOG(ERROR) << "Attempt to sync bad ExtensionSpecifics (bad update URL):\n"
                << GetExtensionSpecificsLogMessage(specifics);
+    RecordBadSyncData(BAD_UPDATE_URL);
+    return false;
   }
 
   id_ = specifics.id();
   update_url_ = specifics_update_url;
   version_ = specifics_version;
   enabled_ = specifics.enabled();
   incognito_enabled_ = specifics.incognito_enabled();
   if (specifics.has_all_urls_enabled()) {
     all_urls_enabled_ =
         specifics.all_urls_enabled() ? BOOLEAN_TRUE : BOOLEAN_FALSE;
   } else {
     // Set this explicitly (even though it's the default) on the offchance
     // that someone is re-using an ExtensionSyncData object.
     all_urls_enabled_ = BOOLEAN_UNSET;
   }
   remote_install_ = specifics.remote_install();
   installed_by_custodian_ = specifics.installed_by_custodian();
   name_ = specifics.name();
+  return true;
 }
 
 void ExtensionSyncData::set_uninstalled(bool uninstalled) {
   uninstalled_ = uninstalled;
 }
 
-void ExtensionSyncData::PopulateFromSyncData(
+bool ExtensionSyncData::PopulateFromSyncData(
     const syncer::SyncData& sync_data) {
   const sync_pb::EntitySpecifics& entity_specifics = sync_data.GetSpecifics();
 
-  if (entity_specifics.has_extension()) {
-    PopulateFromExtensionSpecifics(entity_specifics.extension());
-  } else {
-    LOG(FATAL) << "Attempt to sync bad EntitySpecifics.";
-  }
+  if (entity_specifics.has_extension())
+    return PopulateFromExtensionSpecifics(entity_specifics.extension());
+
+  LOG(ERROR) << "Attempt to sync bad EntitySpecifics: no extension data.";
+  RecordBadSyncData(NO_EXTENSION_SPECIFICS);
+  return false;
 }
 
 }  // namespace extensions