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/*
* Copyright (C) 2011 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_INTERN_TABLE_H_
#define ART_RUNTIME_INTERN_TABLE_H_
#include <unordered_set>
#include "base/allocator.h"
#include "base/mutex.h"
#include "gc_root.h"
#include "object_callbacks.h"
namespace art {
enum VisitRootFlags : uint8_t;
namespace mirror {
class String;
} // namespace mirror
class Transaction;
/**
* Used to intern strings.
*
* There are actually two tables: one that holds strong references to its strings, and one that
* holds weak references. The former is used for string literals, for which there is an effective
* reference from the constant pool. The latter is used for strings interned at runtime via
* String.intern. Some code (XML parsers being a prime example) relies on being able to intern
* arbitrarily many strings for the duration of a parse without permanently increasing the memory
* footprint.
*/
class InternTable {
public:
InternTable();
// Interns a potentially new string in the 'strong' table. (See above.)
mirror::String* InternStrong(int32_t utf16_length, const char* utf8_data)
SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
// Interns a potentially new string in the 'strong' table. (See above.)
mirror::String* InternStrong(const char* utf8_data)
SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
// Interns a potentially new string in the 'strong' table. (See above.)
mirror::String* InternStrong(mirror::String* s) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
// Interns a potentially new string in the 'weak' table. (See above.)
mirror::String* InternWeak(mirror::String* s) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
void SweepInternTableWeaks(IsMarkedCallback* callback, void* arg)
SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
bool ContainsWeak(mirror::String* s) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
size_t Size() const;
size_t StrongSize() const;
size_t WeakSize() const;
void VisitRoots(RootCallback* callback, void* arg, VisitRootFlags flags)
SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
void DumpForSigQuit(std::ostream& os) const;
void DisallowNewInterns() EXCLUSIVE_LOCKS_REQUIRED(Locks::mutator_lock_);
void AllowNewInterns() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
private:
class StringHashEquals {
public:
std::size_t operator()(const GcRoot<mirror::String>& root) NO_THREAD_SAFETY_ANALYSIS;
bool operator()(const GcRoot<mirror::String>& a, const GcRoot<mirror::String>& b)
NO_THREAD_SAFETY_ANALYSIS;
};
typedef std::unordered_set<GcRoot<mirror::String>, StringHashEquals, StringHashEquals,
TrackingAllocator<GcRoot<mirror::String>, kAllocatorTagInternTable>> Table;
mirror::String* Insert(mirror::String* s, bool is_strong)
LOCKS_EXCLUDED(Locks::intern_table_lock_)
SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
mirror::String* LookupStrong(mirror::String* s)
SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
mirror::String* LookupWeak(mirror::String* s)
SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
mirror::String* Lookup(Table* table, mirror::String* s)
SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
mirror::String* InsertStrong(mirror::String* s)
EXCLUSIVE_LOCKS_REQUIRED(Locks::intern_table_lock_);
mirror::String* InsertWeak(mirror::String* s)
EXCLUSIVE_LOCKS_REQUIRED(Locks::intern_table_lock_);
void RemoveStrong(mirror::String* s)
SHARED_LOCKS_REQUIRED(Locks::mutator_lock_)
EXCLUSIVE_LOCKS_REQUIRED(Locks::intern_table_lock_);
void RemoveWeak(mirror::String* s)
SHARED_LOCKS_REQUIRED(Locks::mutator_lock_)
EXCLUSIVE_LOCKS_REQUIRED(Locks::intern_table_lock_);
void Remove(Table* table, mirror::String* s)
SHARED_LOCKS_REQUIRED(Locks::mutator_lock_)
EXCLUSIVE_LOCKS_REQUIRED(Locks::intern_table_lock_);
// Transaction rollback access.
mirror::String* InsertStrongFromTransaction(mirror::String* s)
EXCLUSIVE_LOCKS_REQUIRED(Locks::intern_table_lock_);
mirror::String* InsertWeakFromTransaction(mirror::String* s)
EXCLUSIVE_LOCKS_REQUIRED(Locks::intern_table_lock_);
void RemoveStrongFromTransaction(mirror::String* s)
SHARED_LOCKS_REQUIRED(Locks::mutator_lock_)
EXCLUSIVE_LOCKS_REQUIRED(Locks::intern_table_lock_);
void RemoveWeakFromTransaction(mirror::String* s)
SHARED_LOCKS_REQUIRED(Locks::mutator_lock_)
EXCLUSIVE_LOCKS_REQUIRED(Locks::intern_table_lock_);
friend class Transaction;
bool log_new_roots_ GUARDED_BY(Locks::intern_table_lock_);
bool allow_new_interns_ GUARDED_BY(Locks::intern_table_lock_);
ConditionVariable new_intern_condition_ GUARDED_BY(Locks::intern_table_lock_);
// Since this contains (strong) roots, they need a read barrier to
// enable concurrent intern table (strong) root scan. Do not
// directly access the strings in it. Use functions that contain
// read barriers.
Table strong_interns_ GUARDED_BY(Locks::intern_table_lock_);
std::vector<GcRoot<mirror::String>> new_strong_intern_roots_
GUARDED_BY(Locks::intern_table_lock_);
// Since this contains (weak) roots, they need a read barrier. Do
// not directly access the strings in it. Use functions that contain
// read barriers.
Table weak_interns_ GUARDED_BY(Locks::intern_table_lock_);
};
} // namespace art
#endif // ART_RUNTIME_INTERN_TABLE_H_
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