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// 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.
#include "chrome/browser/chromeos/policy/cloud_external_data_store.h"
#include <set>
#include "base/logging.h"
#include "base/sequenced_task_runner.h"
#include "base/strings/string_number_conversions.h"
#include "components/policy/core/common/cloud/resource_cache.h"
#include "crypto/sha2.h"
namespace policy {
namespace {
// Encodes (policy, hash) into a single string.
std::string GetSubkey(const std::string& policy, const std::string& hash) {
DCHECK(!policy.empty());
DCHECK(!hash.empty());
return base::IntToString(policy.size()) + ":" +
base::IntToString(hash.size()) + ":" +
policy + hash;
}
} // namespace
CloudExternalDataStore::CloudExternalDataStore(
const std::string& cache_key,
scoped_refptr<base::SequencedTaskRunner> task_runner,
ResourceCache* cache)
: cache_key_(cache_key),
task_runner_(task_runner),
cache_(cache) {
}
CloudExternalDataStore::~CloudExternalDataStore() {
DCHECK(task_runner_->RunsTasksOnCurrentThread());
}
void CloudExternalDataStore::Prune(
const CloudExternalDataManager::Metadata& metadata) {
DCHECK(task_runner_->RunsTasksOnCurrentThread());
std::set<std::string> subkeys_to_keep;
for (CloudExternalDataManager::Metadata::const_iterator it = metadata.begin();
it != metadata.end(); ++it) {
subkeys_to_keep.insert(GetSubkey(it->first, it->second.hash));
}
cache_->PurgeOtherSubkeys(cache_key_, subkeys_to_keep);
}
bool CloudExternalDataStore::Store(const std::string& policy,
const std::string& hash,
const std::string& data) {
DCHECK(task_runner_->RunsTasksOnCurrentThread());
return cache_->Store(cache_key_, GetSubkey(policy, hash), data);
}
bool CloudExternalDataStore::Load(const std::string& policy,
const std::string& hash,
size_t max_size,
std::string* data) {
DCHECK(task_runner_->RunsTasksOnCurrentThread());
const std::string subkey = GetSubkey(policy, hash);
if (cache_->Load(cache_key_, subkey, data)) {
if (data->size() <= max_size && crypto::SHA256HashString(*data) == hash)
return true;
// If the data is larger than allowed or does not match the expected hash,
// delete the entry.
cache_->Delete(cache_key_, subkey);
data->clear();
}
return false;
}
} // namespace policy
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