handle a race condition where a cursor receives an inflight onChange after the... (866647f9) · Commits · e / os / android_frameworks_base

core/java/android/content/ContentQueryMap.java

+17 −9

Original line number	Diff line number	Diff line
		@@ -33,7 +33,7 @@ import java.util.Observable;
		* The cursor data is accessed by row key and column name via getValue().
		*/
		public class ContentQueryMap extends Observable {
		private Cursor mCursor;
		private volatile Cursor mCursor;
		private String[] mColumnNames;
		private int mKeyColumn;

		@@ -71,7 +71,7 @@ public class ContentQueryMap extends Observable {
		// ContentProvider then read it once into the cache. Otherwise the cache will be filled
		// automatically.
		if (!keepUpdated) {
		readCursorIntoCache();
		readCursorIntoCache(cursor);
		}
		}

		@@ -128,27 +128,35 @@ public class ContentQueryMap extends Observable {

		/** Requeries the cursor and reads the contents into the cache */
		public void requery() {
		final Cursor cursor = mCursor;
		if (cursor == null) {
		// If mCursor is null then it means there was a requery() in flight
		// while another thread called close(), which nulls out mCursor.
		// If this happens ignore the requery() since we are closed anyways.
		return;
		}
		mDirty = false;
		if (!mCursor.requery()) {
		throw new IllegalStateException("trying to requery an already closed cursor");
		if (!cursor.requery()) {
		// again, don't do anything if the cursor is already closed
		return;
		}
		readCursorIntoCache();
		readCursorIntoCache(cursor);
		setChanged();
		notifyObservers();
		}

		private synchronized void readCursorIntoCache() {
		private synchronized void readCursorIntoCache(Cursor cursor) {
		// Make a new map so old values returned by getRows() are undisturbed.
		int capacity = mValues != null ? mValues.size() : 0;
		mValues = new HashMap<String, ContentValues>(capacity);
		while (mCursor.moveToNext()) {
		while (cursor.moveToNext()) {
		ContentValues values = new ContentValues();
		for (int i = 0; i < mColumnNames.length; i++) {
		if (i != mKeyColumn) {
		values.put(mColumnNames[i], mCursor.getString(i));
		values.put(mColumnNames[i], cursor.getString(i));
		}
		}
		mValues.put(mCursor.getString(mKeyColumn), values);
		mValues.put(cursor.getString(mKeyColumn), values);
		}
		}