864d304156
Reflects refactoring of JNI helper code that depends on private methods within libnativehelper. Bug: 151443957 Test: Treehugger Change-Id: I7af128f42ae89a77a8e3fb113ea533331153c535 Merged-In: I7af128f42ae89a77a8e3fb113ea533331153c535 Exempt-From-Owner-Approval: cherry pick (cherry picked from commit 329c612e3d5ae440bf13e1f5fc9a4012263524e9)
84 lines
3.1 KiB
C++
84 lines
3.1 KiB
C++
/*
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* Copyright (C) 2008 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef _ANDROID_NIO_UTILS_H_
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#define _ANDROID_NIO_UTILS_H_
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#include <jni.h>
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#include <cstddef>
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namespace android {
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/**
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* Class providing scoped access to the memory backing a java.nio.Buffer instance.
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*
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* Instances of this class should only be allocated on the stack as heap allocation is not
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* supported.
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*
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* Instances of this class do not create any global references for performance reasons.
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*/
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class AutoBufferPointer final {
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public:
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/** Constructor for an AutoBufferPointer instance.
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*
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* @param env The current JNI env
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* @param nioBuffer Instance of a java.nio.Buffer whose memory will be accessed.
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* @param commit JNI_TRUE if the underlying memory will be updated and should be
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* copied back to the managed heap. JNI_FALSE if the data will
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* not be modified or the modifications may be discarded.
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*
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* The commit parameter is only applicable if the buffer is backed by a managed heap
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* array and the runtime had to provide a copy of the data rather than the original data.
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*/
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AutoBufferPointer(JNIEnv* env, jobject nioBuffer, jboolean commit);
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/** Destructor for an AutoBufferPointer instance.
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*
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* Releases critical managed heap array pointer if acquired.
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*/
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~AutoBufferPointer();
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/**
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* Returns a pointer to the current position of the buffer provided to the constructor. This
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* pointer is only valid whilst the AutoBufferPointer instance remains in scope.
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*/
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void* pointer() const { return fPointer; }
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private:
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JNIEnv* const fEnv;
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void* fPointer; // Pointer to current buffer position when constructed.
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void* fElements; // Pointer to array element 0 (null if buffer is direct, may be
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// within fArray or point to a copy of the array).
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jarray fArray; // Pointer to array on managed heap.
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const jboolean fCommit; // Flag to commit data to source (when fElements is a copy of fArray).
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// Unsupported constructors and operators.
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AutoBufferPointer() = delete;
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AutoBufferPointer(AutoBufferPointer&) = delete;
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AutoBufferPointer& operator=(AutoBufferPointer&) = delete;
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static void* operator new(size_t);
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static void* operator new[](size_t);
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static void* operator new(size_t, void*);
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static void* operator new[](size_t, void*);
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static void operator delete(void*, size_t);
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static void operator delete[](void*, size_t);
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};
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} /* namespace android */
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#endif // _ANDROID_NIO_UTILS_H_
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