/*
* Copyright (C) 2015 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_CLASS_TABLE_H_
#define ART_RUNTIME_CLASS_TABLE_H_
#include <string>
#include <utility>
#include <vector>
#include "base/allocator.h"
#include "base/hash_set.h"
#include "base/macros.h"
#include "base/mutex.h"
#include "dex_file.h"
#include "gc_root.h"
#include "object_callbacks.h"
#include "runtime.h"
namespace art {
namespace mirror {
class ClassLoader;
} // namespace mirror
// Each loader has a ClassTable
class ClassTable {
public:
class ClassDescriptorHashEquals {
public:
// uint32_t for cross compilation.
uint32_t operator()(const GcRoot<mirror::Class>& root) const NO_THREAD_SAFETY_ANALYSIS;
// Same class loader and descriptor.
bool operator()(const GcRoot<mirror::Class>& a, const GcRoot<mirror::Class>& b) const
NO_THREAD_SAFETY_ANALYSIS;;
// Same descriptor.
bool operator()(const GcRoot<mirror::Class>& a, const char* descriptor) const
NO_THREAD_SAFETY_ANALYSIS;
// uint32_t for cross compilation.
uint32_t operator()(const char* descriptor) const NO_THREAD_SAFETY_ANALYSIS;
};
class GcRootEmptyFn {
public:
void MakeEmpty(GcRoot<mirror::Class>& item) const {
item = GcRoot<mirror::Class>();
}
bool IsEmpty(const GcRoot<mirror::Class>& item) const {
return item.IsNull();
}
};
// hash set which hashes class descriptor, and compares descriptors and class loaders. Results
// should be compared for a matching Class descriptor and class loader.
typedef HashSet<GcRoot<mirror::Class>, GcRootEmptyFn, ClassDescriptorHashEquals,
ClassDescriptorHashEquals, TrackingAllocator<GcRoot<mirror::Class>, kAllocatorTagClassTable>>
ClassSet;
ClassTable();
// Used by image writer for checking.
bool Contains(mirror::Class* klass)
REQUIRES(!lock_)
SHARED_REQUIRES(Locks::mutator_lock_);
// Freeze the current class tables by allocating a new table and never updating or modifying the
// existing table. This helps prevents dirty pages after caused by inserting after zygote fork.
void FreezeSnapshot()
REQUIRES(!lock_)
SHARED_REQUIRES(Locks::mutator_lock_);
// Returns the number of classes in previous snapshots.
size_t NumZygoteClasses() const REQUIRES(!lock_);
// Returns all off the classes in the lastest snapshot.
size_t NumNonZygoteClasses() const REQUIRES(!lock_);
// Update a class in the table with the new class. Returns the existing class which was replaced.
mirror::Class* UpdateClass(const char* descriptor, mirror::Class* new_klass, size_t hash)
REQUIRES(!lock_)
SHARED_REQUIRES(Locks::mutator_lock_);
// NO_THREAD_SAFETY_ANALYSIS for object marking requiring heap bitmap lock.
template<class Visitor>
void VisitRoots(Visitor& visitor)
NO_THREAD_SAFETY_ANALYSIS
REQUIRES(!lock_)
SHARED_REQUIRES(Locks::mutator_lock_);
template<class Visitor>
void VisitRoots(const Visitor& visitor)
NO_THREAD_SAFETY_ANALYSIS
REQUIRES(!lock_)
SHARED_REQUIRES(Locks::mutator_lock_);
// Stops visit if the visitor returns false.
template <typename Visitor>
bool Visit(Visitor& visitor)
REQUIRES(!lock_)
SHARED_REQUIRES(Locks::mutator_lock_);
// Return the first class that matches the descriptor. Returns null if there are none.
mirror::Class* Lookup(const char* descriptor, size_t hash)
REQUIRES(!lock_)
SHARED_REQUIRES(Locks::mutator_lock_);
// Return the first class that matches the descriptor of klass. Returns null if there are none.
mirror::Class* LookupByDescriptor(mirror::Class* klass)
REQUIRES(!lock_)
SHARED_REQUIRES(Locks::mutator_lock_);
void Insert(mirror::Class* klass)
REQUIRES(!lock_)
SHARED_REQUIRES(Locks::mutator_lock_);
void InsertWithHash(mirror::Class* klass, size_t hash)
REQUIRES(!lock_)
SHARED_REQUIRES(Locks::mutator_lock_);
// Returns true if the class was found and removed, false otherwise.
bool Remove(const char* descriptor)
REQUIRES(!lock_)
SHARED_REQUIRES(Locks::mutator_lock_);
// Return true if we inserted the strong root, false if it already exists.
bool InsertStrongRoot(mirror::Object* obj)
REQUIRES(!lock_)
SHARED_REQUIRES(Locks::mutator_lock_);
// Combines all of the tables into one class set.
size_t WriteToMemory(uint8_t* ptr) const
REQUIRES(!lock_)
SHARED_REQUIRES(Locks::mutator_lock_);
// Read a table from ptr and put it at the front of the class set.
size_t ReadFromMemory(uint8_t* ptr)
REQUIRES(!lock_)
SHARED_REQUIRES(Locks::mutator_lock_);
// Add a class set to the front of classes.
void AddClassSet(ClassSet&& set)
REQUIRES(!lock_)
SHARED_REQUIRES(Locks::mutator_lock_);
// Clear strong roots (other than classes themselves).
void ClearStrongRoots()
REQUIRES(!lock_)
SHARED_REQUIRES(Locks::mutator_lock_);
ReaderWriterMutex& GetLock() {
return lock_;
}
private:
// Lock to guard inserting and removing.
mutable ReaderWriterMutex lock_;
// We have a vector to help prevent dirty pages after the zygote forks by calling FreezeSnapshot.
std::vector<ClassSet> classes_ GUARDED_BY(lock_);
// Extra strong roots that can be either dex files or dex caches. Dex files used by the class
// loader which may not be owned by the class loader must be held strongly live. Also dex caches
// are held live to prevent them being unloading once they have classes in them.
std::vector<GcRoot<mirror::Object>> strong_roots_ GUARDED_BY(lock_);
};
} // namespace art
#endif // ART_RUNTIME_CLASS_TABLE_H_