// Copyright 2013 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.
#ifndef CHROME_BROWSER_CHROMEOS_POLICY_CLOUD_EXTERNAL_DATA_STORE_H_
#define CHROME_BROWSER_CHROMEOS_POLICY_CLOUD_EXTERNAL_DATA_STORE_H_
#include <string>
#include "base/basictypes.h"
#include "base/memory/ref_counted.h"
#include "components/policy/core/common/cloud/cloud_external_data_manager.h"
namespace base {
class SequencedTaskRunner;
}
namespace policy {
class ResourceCache;
// Stores external data referenced by policies. Data is keyed by (policy, hash),
// the name of the policy referencing it and its SHA1 hash. Outdated entries are
// removed by calling Prune() with the list of (policy, hash) entries that are
// to be kept. Instances of this class may be created on any thread and may
// share the same cache, however:
// * After creation, the cache and all stores using it must always be accessed
// via the same |task_runner| only.
// * Stores sharing a cache must use different cache_keys to avoid namespace
// overlaps.
// * The cache must outlive all stores using it.
class CloudExternalDataStore {
public:
CloudExternalDataStore(const std::string& cache_key,
scoped_refptr<base::SequencedTaskRunner> task_runner,
ResourceCache* cache);
~CloudExternalDataStore();
// Removes all entries from the store whose (policy, hash) pair is not found
// in |metadata|.
void Prune(const CloudExternalDataManager::Metadata& metadata);
// Stores |data| under (policy, hash). Returns true if the store succeeded.
bool Store(const std::string& policy,
const std::string& hash,
const std::string& data);
// Loads the entry at (policy, hash) into |data|, verifies that it does not
// exceed |max_size| and matches the expected |hash|, then returns true.
// Returns false if no entry is found at (policy, hash), there is a problem
// during the load, the entry exceeds |max_size| or does not match |hash|.
bool Load(const std::string& policy,
const std::string& hash,
size_t max_size,
std::string* data);
private:
std::string cache_key_;
// Task runner that |this| runs on.
scoped_refptr<base::SequencedTaskRunner> task_runner_;
ResourceCache* cache_; // Not owned.
DISALLOW_COPY_AND_ASSIGN(CloudExternalDataStore);
};
} // namespace policy
#endif // CHROME_BROWSER_CHROMEOS_POLICY_CLOUD_EXTERNAL_DATA_STORE_H_