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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
package org.mozilla.gecko.mozglue;
import android.annotation.SuppressLint;
import android.os.MemoryFile;
import android.os.Parcel;
import android.os.ParcelFileDescriptor;
import android.os.Parcelable;
import android.util.Log;
import java.io.FileDescriptor;
import java.io.IOException;
import java.lang.reflect.Method;
@SuppressLint("DiscouragedPrivateApi")
public class SharedMemory implements Parcelable {
private static final String LOGTAG = "GeckoShmem";
private static final Method sGetFDMethod;
private ParcelFileDescriptor mDescriptor;
private int mSize;
private int mId;
private long mHandle; // The native pointer.
private boolean mIsMapped;
private MemoryFile mBackedFile;
// MemoryFile.getFileDescriptor() is hidden. :(
static {
Method method = null;
try {
method = MemoryFile.class.getDeclaredMethod("getFileDescriptor");
} catch (final NoSuchMethodException e) {
e.printStackTrace();
}
sGetFDMethod = method;
}
private SharedMemory(final Parcel in) {
mDescriptor = in.readFileDescriptor();
mSize = in.readInt();
mId = in.readInt();
}
public static final Creator<SharedMemory> CREATOR =
new Creator<SharedMemory>() {
@Override
public SharedMemory createFromParcel(final Parcel in) {
return new SharedMemory(in);
}
@Override
public SharedMemory[] newArray(final int size) {
return new SharedMemory[size];
}
};
@Override
public int describeContents() {
return CONTENTS_FILE_DESCRIPTOR;
}
@Override
public void writeToParcel(final Parcel dest, final int flags) {
// We don't want ParcelFileDescriptor.writeToParcel() to close the fd.
dest.writeFileDescriptor(mDescriptor.getFileDescriptor());
dest.writeInt(mSize);
dest.writeInt(mId);
}
public SharedMemory(final int id, final int size) throws NoSuchMethodException, IOException {
if (sGetFDMethod == null) {
throw new NoSuchMethodException("MemoryFile.getFileDescriptor() doesn't exist.");
}
mBackedFile = new MemoryFile(null, size);
try {
final FileDescriptor fd = (FileDescriptor) sGetFDMethod.invoke(mBackedFile);
mDescriptor = ParcelFileDescriptor.dup(fd);
mSize = size;
mId = id;
mBackedFile.allowPurging(false);
} catch (final Exception e) {
e.printStackTrace();
close();
throw new IOException(e.getMessage());
}
}
public void flush() {
if (!mIsMapped) {
return;
}
unmap(mHandle, mSize);
mHandle = 0;
mIsMapped = false;
}
public void close() {
flush();
if (mDescriptor != null) {
try {
mDescriptor.close();
} catch (final IOException e) {
e.printStackTrace();
}
mDescriptor = null;
}
}
// Should only be called by process that allocates shared memory.
public void dispose() {
if (!isValid()) {
return;
}
close();
if (mBackedFile != null) {
mBackedFile.close();
mBackedFile = null;
}
}
private native void unmap(long address, int size);
public boolean isValid() {
return mDescriptor != null;
}
public int getSize() {
return mSize;
}
private int getFD() {
return isValid() ? mDescriptor.getFd() : -1;
}
public long getPointer() {
if (!isValid()) {
return 0;
}
if (!mIsMapped) {
try {
mHandle = map(getFD(), mSize);
} catch (final NullPointerException e) {
Log.e(LOGTAG, "SharedMemory#" + mId + " error.", e);
throw e;
}
if (mHandle != 0) {
mIsMapped = true;
}
}
return mHandle;
}
private native long map(int fd, int size);
@Override
protected void finalize() throws Throwable {
if (mBackedFile != null) {
Log.w(LOGTAG, "dispose() not called before finalizing");
}
dispose();
super.finalize();
}
@Override
public String toString() {
return "SHM("
+ getSize()
+ " bytes): id="
+ mId
+ ", backing="
+ mBackedFile
+ ",fd="
+ mDescriptor;
}
@Override
public boolean equals(final Object that) {
return (this == that) || ((that instanceof SharedMemory) && (hashCode() == that.hashCode()));
}
@Override
public int hashCode() {
return mId;
}
}
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