upload android base code part6

android/system/update_engine/update_manager/evaluation_context-inl.h

@@ -0,0 +1,55 @@
+//
+// Copyright (C) 2014 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+#ifndef UPDATE_ENGINE_UPDATE_MANAGER_EVALUATION_CONTEXT_INL_H_
+#define UPDATE_ENGINE_UPDATE_MANAGER_EVALUATION_CONTEXT_INL_H_
+
+#include <string>
+
+#include <base/logging.h>
+
+namespace chromeos_update_manager {
+
+template<typename T>
+const T* EvaluationContext::GetValue(Variable<T>* var) {
+  if (var == nullptr) {
+    LOG(ERROR) << "GetValue received an uninitialized variable.";
+    return nullptr;
+  }
+
+  // Search for the value on the cache first.
+  ValueCacheMap::iterator it = value_cache_.find(var);
+  if (it != value_cache_.end())
+    return reinterpret_cast<const T*>(it->second.value());
+
+  // Get the value from the variable if not found on the cache.
+  std::string errmsg;
+  const T* result = var->GetValue(RemainingTime(evaluation_monotonic_deadline_),
+                                  &errmsg);
+  if (result == nullptr) {
+    LOG(WARNING) << "Error reading Variable " << var->GetName() << ": \""
+        << errmsg << "\"";
+  }
+  // Cache the value for the next time. The map of CachedValues keeps the
+  // ownership of the pointer until the map is destroyed.
+  value_cache_.emplace(
+    static_cast<BaseVariable*>(var), BoxedValue(result));
+  return result;
+}
+
+}  // namespace chromeos_update_manager
+
+#endif  // UPDATE_ENGINE_UPDATE_MANAGER_EVALUATION_CONTEXT_INL_H_