| /* |
| * Copyright (C) 2019 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. |
| */ |
| |
| package android.os; |
| |
| import android.annotation.IntRange; |
| import android.annotation.NonNull; |
| import android.annotation.Nullable; |
| import android.annotation.SystemApi; |
| import android.annotation.TestApi; |
| |
| import java.io.Closeable; |
| import java.io.IOException; |
| |
| /** |
| * An abstract representation of a memory block, as representing by the HIDL system. |
| * |
| * The block is defined by a {name, size, handle} tuple, where the name is used to determine how to |
| * interpret the handle. The underlying handle is assumed to be owned by this instance and will be |
| * closed as soon as {@link #close()} is called on this instance, or this instance has been |
| * finalized (the latter supports using it in a shared manner without having to worry about who owns |
| * this instance, the former is more efficient resource-wise and is recommended for most use-cases). |
| * Note, however, that ownership of the handle does not necessarily imply ownership of the |
| * underlying file descriptors - the underlying handle may or may not own them. If you want the |
| * underlying handle to outlive this instance, call {@link #releaseHandle()} to obtain the handle |
| * and detach the ownership relationship. |
| * |
| * @hide |
| */ |
| @SystemApi |
| @TestApi |
| public class HidlMemory implements Closeable { |
| private final @NonNull String mName; |
| private final long mSize; |
| private @Nullable NativeHandle mHandle; |
| private long mNativeContext; // For use of native code. |
| |
| /** |
| * Constructor. |
| * |
| * @param name The name of the IMapper service used to resolve the handle (e.g. "ashmem"). |
| * @param size The (non-negative) size in bytes of the memory block. |
| * @param handle The handle. May be null. This instance will own the handle and will close it |
| * as soon as {@link #close()} is called or the object is destroyed. This, this |
| * handle instance should generally not be shared with other clients. |
| */ |
| public HidlMemory(@NonNull String name, @IntRange(from = 0) long size, |
| @Nullable NativeHandle handle) { |
| mName = name; |
| mSize = size; |
| mHandle = handle; |
| } |
| |
| /** |
| * Create a copy of this instance, where the underlying handle (and its file descriptors) have |
| * been duplicated. |
| */ |
| @NonNull |
| public HidlMemory dup() throws IOException { |
| return new HidlMemory(mName, mSize, mHandle != null ? mHandle.dup() : null); |
| } |
| |
| /** |
| * Close the underlying native handle. No-op if handle is null or has been released using {@link |
| * #releaseHandle()}. |
| */ |
| @Override |
| public void close() throws IOException { |
| if (mHandle != null) { |
| mHandle.close(); |
| } |
| } |
| |
| /** |
| * Disowns the underlying handle and returns it. The underlying handle becomes null. |
| * |
| * @return The underlying handle. |
| */ |
| @Nullable |
| public NativeHandle releaseHandle() { |
| NativeHandle handle = mHandle; |
| mHandle = null; |
| return handle; |
| } |
| |
| /** |
| * Gets the name, which represents how the handle is to be interpreted. |
| * |
| * @return The name. |
| */ |
| @NonNull |
| public String getName() { |
| return mName; |
| } |
| |
| /** |
| * Gets the size of the block, in bytes. |
| * |
| * @return The size. |
| */ |
| public long getSize() { |
| return mSize; |
| } |
| |
| /** |
| * Gets a native handle. The actual interpretation depends on the name and is implementation |
| * defined. |
| * |
| * @return The native handle. |
| */ |
| @Nullable |
| public NativeHandle getHandle() { |
| return mHandle; |
| } |
| |
| @Override |
| protected void finalize() { |
| try { |
| close(); |
| } catch (IOException e) { |
| throw new RuntimeException(e); |
| } finally { |
| nativeFinalize(); |
| } |
| } |
| |
| private native void nativeFinalize(); |
| } |