chromeos: Wait for service to be available when getting system salt

chromeos/cryptohome/system_salt_getter.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 "chromeos/cryptohome/system_salt_getter.h"
 
 #include "base/bind.h"
 #include "base/location.h"
 #include "base/message_loop/message_loop_proxy.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_util.h"
 #include "chromeos/dbus/cryptohome_client.h"
 #include "chromeos/dbus/dbus_thread_manager.h"
 
 namespace chromeos {
 namespace {
 
 SystemSaltGetter* g_system_salt_getter = NULL;
 
 }  // namespace
 
-SystemSaltGetter::SystemSaltGetter() {
+SystemSaltGetter::SystemSaltGetter() : weak_ptr_factory_(this) {
 }
 
 SystemSaltGetter::~SystemSaltGetter() {
 }
 
 void SystemSaltGetter::GetSystemSalt(
     const GetSystemSaltCallback& callback) {
-  // TODO(hashimoto): Stop using GetSystemSaltSynt(). crbug.com/141009
-  base::MessageLoopProxy::current()->PostTask(
-      FROM_HERE, base::Bind(callback, GetSystemSaltSync()));
+  DBusThreadManager::Get()->GetCryptohomeClient()->WaitForServiceToBeAvailable(
+      base::Bind(&SystemSaltGetter::GetSystemSaltInternal,
+                 weak_ptr_factory_.GetWeakPtr(),
+                 callback));
 }
 
 std::string SystemSaltGetter::GetSystemSaltSync() {
   LoadSystemSalt();  // no-op if it's already loaded.
   return system_salt_;
 }
 
 std::string SystemSaltGetter::GetCachedSystemSalt() {
   return system_salt_;
 }
 
+void SystemSaltGetter::GetSystemSaltInternal(
+    const GetSystemSaltCallback& callback,
+    bool service_is_available) {
+  LOG_IF(ERROR, !service_is_available) << "WaitForServiceToBeAvailable failed.";
+  // TODO(hashimoto): Stop using GetSystemSaltSync(). crbug.com/141009
+  callback.Run(GetSystemSaltSync());
+}
+
 void SystemSaltGetter::LoadSystemSalt() {
   if (!system_salt_.empty())
     return;
   std::vector<uint8> salt;
   DBusThreadManager::Get()->GetCryptohomeClient()->GetSystemSalt(&salt);
   if (salt.empty() || salt.size() % 2 != 0U) {
     LOG(WARNING) << "System salt not available";
     return;
   }
   system_salt_ = ConvertRawSaltToHexString(salt);
@@ skipping 25 matching lines @@
 }
 
 // static
 std::string SystemSaltGetter::ConvertRawSaltToHexString(
     const std::vector<uint8>& salt) {
   return StringToLowerASCII(base::HexEncode(
       reinterpret_cast<const void*>(salt.data()), salt.size()));
 }
 
 }  // namespace chromeos