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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_SRC_STACK_INDIRECT_REFERENCE_TABLE_H_
#define ART_SRC_STACK_INDIRECT_REFERENCE_TABLE_H_
#include "logging.h"
#include "macros.h"
#include "thread.h"
namespace art {
class Object;
// Stack allocated indirect reference table. It can allocated within
// the bridge frame between managed and native code backed by stack
// storage or manually allocated by SirtRef to hold one reference.
class StackIndirectReferenceTable {
public:
explicit StackIndirectReferenceTable(Object* object) {
number_of_references_ = 1;
references_[0] = object;
Thread::Current()->PushSirt(this);
}
~StackIndirectReferenceTable() {
StackIndirectReferenceTable* sirt = Thread::Current()->PopSirt();
CHECK_EQ(this, sirt);
}
// Number of references contained within this SIRT
size_t NumberOfReferences() const {
return number_of_references_;
}
// Link to previous SIRT or NULL
StackIndirectReferenceTable* GetLink() const {
return link_;
}
void SetLink(StackIndirectReferenceTable* sirt) {
DCHECK_NE(this, sirt);
link_ = sirt;
}
Object* GetReference(size_t i) const {
DCHECK_LT(i, number_of_references_);
return references_[i];
}
void SetReference(size_t i, Object* object) {
DCHECK_LT(i, number_of_references_);
references_[i] = object;
}
bool Contains(Object** sirt_entry) const {
// A SIRT should always contain something. One created by the
// jni_compiler should have a jobject/jclass as a native method is
// passed in a this pointer or a class
DCHECK_GT(number_of_references_, 0U);
return ((&references_[0] <= sirt_entry)
&& (sirt_entry <= (&references_[number_of_references_ - 1])));
}
// Offset of length within SIRT, used by generated code
static size_t NumberOfReferencesOffset() {
return OFFSETOF_MEMBER(StackIndirectReferenceTable, number_of_references_);
}
// Offset of link within SIRT, used by generated code
static size_t LinkOffset() {
return OFFSETOF_MEMBER(StackIndirectReferenceTable, link_);
}
private:
StackIndirectReferenceTable() {}
size_t number_of_references_;
StackIndirectReferenceTable* link_;
// number_of_references_ are available if this is allocated and filled in by jni_compiler.
Object* references_[1];
DISALLOW_COPY_AND_ASSIGN(StackIndirectReferenceTable);
};
template<class T>
class SirtRef {
public:
explicit SirtRef(T* object) : sirt_(object) {}
~SirtRef() {}
T& operator*() const { return *get(); }
T* operator->() const { return get(); }
T* get() const {
return down_cast<T*>(sirt_.GetReference(0));
}
void reset(T* object = NULL) {
sirt_.SetReference(0, object);
}
private:
StackIndirectReferenceTable sirt_;
DISALLOW_COPY_AND_ASSIGN(SirtRef);
};
} // namespace art
#endif // ART_SRC_STACK_INDIRECT_REFERENCE_TABLE_H_
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