aosp12/art/runtime/dex_reference_collection.h

86 lines
2.7 KiB
C++

/*
* Copyright (C) 2017 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_RUNTIME_DEX_REFERENCE_COLLECTION_H_
#define ART_RUNTIME_DEX_REFERENCE_COLLECTION_H_
#include <map>
#include <vector>
#include "base/macros.h"
namespace art {
class DexFile;
// Collection of dex references that is more memory efficient than a vector of <dex, index> pairs.
// Also allows quick lookups of all of the references for a single dex.
template <class IndexType, template<typename Type> class Allocator>
class DexReferenceCollection {
public:
using VectorAllocator = Allocator<IndexType>;
using IndexVector = std::vector<IndexType, VectorAllocator>;
using MapAllocator = Allocator<std::pair<const DexFile*, IndexVector>>;
using DexFileMap = std::map<
const DexFile*,
IndexVector,
std::less<const DexFile*>,
Allocator<std::pair<const DexFile* const, IndexVector>>>;
DexReferenceCollection(const MapAllocator& map_allocator = MapAllocator(),
const VectorAllocator& vector_allocator = VectorAllocator())
: map_(map_allocator),
vector_allocator_(vector_allocator) {}
void AddReference(const DexFile* dex, IndexType index) {
GetOrInsertVector(dex)->push_back(index);
}
DexFileMap& GetMap() {
return map_;
}
size_t NumReferences() const {
size_t ret = 0;
for (auto&& pair : map_) {
ret += pair.second.size();
}
return ret;
}
private:
DexFileMap map_;
const DexFile* current_dex_file_ = nullptr;
IndexVector* current_vector_ = nullptr;
VectorAllocator vector_allocator_;
ALWAYS_INLINE IndexVector* GetOrInsertVector(const DexFile* dex) {
// Optimize for adding to same vector in succession, the cached dex file and vector aims to
// prevent map lookups.
if (UNLIKELY(current_dex_file_ != dex)) {
// There is an assumption that constructing an empty vector wont do any allocations. If this
// incorrect, this might leak for the arena case.
current_vector_ = &map_.emplace(dex, IndexVector(vector_allocator_)).first->second;
current_dex_file_ = dex;
}
return current_vector_;
}
};
} // namespace art
#endif // ART_RUNTIME_DEX_REFERENCE_COLLECTION_H_