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/*
* Copyright (C) 2013 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 ART_COMPILER_UTILS_DEDUPE_SET_H_
#define ART_COMPILER_UTILS_DEDUPE_SET_H_
#include <set>
#include <string>
#include "base/mutex.h"
#include "base/stl_util.h"
#include "base/stringprintf.h"
namespace art {
// A set of Keys that support a HashFunc returning HashType. Used to find duplicates of Key in the
// Add method. The data-structure is thread-safe through the use of internal locks, it also
// supports the lock being sharded.
template <typename Key, typename HashType, typename HashFunc, HashType kShard = 1>
class DedupeSet {
typedef std::pair<HashType, Key*> HashedKey;
class Comparator {
public:
bool operator()(const HashedKey& a, const HashedKey& b) const {
if (a.first != b.first) {
return a.first < b.first;
} else {
return *a.second < *b.second;
}
}
};
public:
Key* Add(Thread* self, const Key& key) {
HashType raw_hash = HashFunc()(key);
HashType shard_hash = raw_hash / kShard;
HashType shard_bin = raw_hash % kShard;
HashedKey hashed_key(shard_hash, const_cast<Key*>(&key));
MutexLock lock(self, *lock_[shard_bin]);
auto it = keys_[shard_bin].find(hashed_key);
if (it != keys_[shard_bin].end()) {
return it->second;
}
hashed_key.second = new Key(key);
keys_[shard_bin].insert(hashed_key);
return hashed_key.second;
}
explicit DedupeSet(const char* set_name) {
for (HashType i = 0; i < kShard; ++i) {
std::ostringstream oss;
oss << set_name << " lock " << i;
lock_name_[i] = oss.str();
lock_[i].reset(new Mutex(lock_name_[i].c_str()));
}
}
~DedupeSet() {
for (HashType i = 0; i < kShard; ++i) {
STLDeleteValues(&keys_[i]);
}
}
private:
std::string lock_name_[kShard];
std::unique_ptr<Mutex> lock_[kShard];
std::set<HashedKey, Comparator> keys_[kShard];
DISALLOW_COPY_AND_ASSIGN(DedupeSet);
};
} // namespace art
#endif // ART_COMPILER_UTILS_DEDUPE_SET_H_
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