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/*
* Copyright (C) 2006 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.database;
import android.os.Bundle;
import android.os.RemoteException;
import android.util.Log;
/**
* Adapts an {@link IBulkCursor} to a {@link Cursor} for use in the local process.
*
* {@hide}
*/
public final class BulkCursorToCursorAdaptor extends AbstractWindowedCursor {
private static final String TAG = "BulkCursor";
private SelfContentObserver mObserverBridge = new SelfContentObserver(this);
private IBulkCursor mBulkCursor;
private String[] mColumns;
private boolean mWantsAllOnMoveCalls;
private int mCount;
/**
* Initializes the adaptor.
* Must be called before first use.
*/
public void initialize(BulkCursorDescriptor d) {
mBulkCursor = d.cursor;
mColumns = d.columnNames;
mRowIdColumnIndex = DatabaseUtils.findRowIdColumnIndex(mColumns);
mWantsAllOnMoveCalls = d.wantsAllOnMoveCalls;
mCount = d.count;
if (d.window != null) {
setWindow(d.window);
}
}
/**
* Gets a SelfDataChangeOberserver that can be sent to a remote
* process to receive change notifications over IPC.
*
* @return A SelfContentObserver hooked up to this Cursor
*/
public IContentObserver getObserver() {
return mObserverBridge.getContentObserver();
}
private void throwIfCursorIsClosed() {
if (mBulkCursor == null) {
throw new StaleDataException("Attempted to access a cursor after it has been closed.");
}
}
@Override
public int getCount() {
throwIfCursorIsClosed();
return mCount;
}
@Override
public boolean onMove(int oldPosition, int newPosition) {
throwIfCursorIsClosed();
try {
// Make sure we have the proper window
if (mWindow == null
|| newPosition < mWindow.getStartPosition()
|| newPosition >= mWindow.getStartPosition() + mWindow.getNumRows()) {
setWindow(mBulkCursor.getWindow(newPosition));
} else if (mWantsAllOnMoveCalls) {
mBulkCursor.onMove(newPosition);
}
} catch (RemoteException ex) {
// We tried to get a window and failed
Log.e(TAG, "Unable to get window because the remote process is dead");
return false;
}
// Couldn't obtain a window, something is wrong
if (mWindow == null) {
return false;
}
return true;
}
@Override
public void deactivate() {
// This will call onInvalidated(), so make sure to do it before calling release,
// which is what actually makes the data set invalid.
super.deactivate();
if (mBulkCursor != null) {
try {
mBulkCursor.deactivate();
} catch (RemoteException ex) {
Log.w(TAG, "Remote process exception when deactivating");
}
}
}
@Override
public void close() {
super.close();
if (mBulkCursor != null) {
try {
mBulkCursor.close();
} catch (RemoteException ex) {
Log.w(TAG, "Remote process exception when closing");
} finally {
mBulkCursor = null;
}
}
}
@Override
public boolean requery() {
throwIfCursorIsClosed();
try {
mCount = mBulkCursor.requery(getObserver());
if (mCount != -1) {
mPos = -1;
closeWindow();
// super.requery() will call onChanged. Do it here instead of relying on the
// observer from the far side so that observers can see a correct value for mCount
// when responding to onChanged.
super.requery();
return true;
} else {
deactivate();
return false;
}
} catch (Exception ex) {
Log.e(TAG, "Unable to requery because the remote process exception " + ex.getMessage());
deactivate();
return false;
}
}
@Override
public String[] getColumnNames() {
throwIfCursorIsClosed();
return mColumns;
}
@Override
public Bundle getExtras() {
throwIfCursorIsClosed();
try {
return mBulkCursor.getExtras();
} catch (RemoteException e) {
// This should never happen because the system kills processes that are using remote
// cursors when the provider process is killed.
throw new RuntimeException(e);
}
}
@Override
public Bundle respond(Bundle extras) {
throwIfCursorIsClosed();
try {
return mBulkCursor.respond(extras);
} catch (RemoteException e) {
// the system kills processes that are using remote cursors when the provider process
// is killed, but this can still happen if this is being called from the system process,
// so, better to log and return an empty bundle.
Log.w(TAG, "respond() threw RemoteException, returning an empty bundle.", e);
return Bundle.EMPTY;
}
}
}
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