Adapt unpaged cursors to paged requests. (e5f868fd) · Commits · e / os / android_frameworks_base

core/java/android/content/ContentProviderNative.java

+2 −0

Original line number	Diff line number	Diff line
		@@ -24,6 +24,7 @@ import android.database.Cursor;
		import android.database.CursorToBulkCursorAdaptor;
		import android.database.DatabaseUtils;
		import android.database.IContentObserver;
		import android.database.PageViewCursor;
		import android.net.Uri;
		import android.os.Binder;
		import android.os.Bundle;
		@@ -103,6 +104,7 @@ abstract public class ContentProviderNative extends Binder implements IContentPr
		if (cursor != null) {
		CursorToBulkCursorAdaptor adaptor = null;

		cursor = PageViewCursor.wrap(cursor, queryArgs);
		try {
		adaptor = new CursorToBulkCursorAdaptor(cursor, observer,
		getProviderName());

core/java/android/database/PageViewCursor.java

0 → 100644

+245 −0

Original line number	Diff line number	Diff line
		/*
		* Copyright (C) 2017 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 static com.android.internal.util.Preconditions.checkArgument;

		import android.annotation.Nullable;
		import android.content.ContentResolver;
		import android.os.Bundle;
		import android.util.Log;
		import android.util.MathUtils;

		import com.android.internal.annotations.VisibleForTesting;
		import com.android.internal.util.ArrayUtils;

		/**
		* Cursor wrapper that provides visibility into a subset of a wrapped cursor.
		*
		* The window is specified by offset and limit.
		*
		* @hide
		*/
		public final class PageViewCursor extends CrossProcessCursorWrapper {

		/**
		* An extra added to results that are auto-paged using the wrapper.
		*/
		public static final String EXTRA_AUTO_PAGED = "android.content.extra.AUTO_PAGED";

		private static final String TAG = "PageViewCursor";
		private static final boolean DEBUG = false;
		private static final boolean VERBOSE = false;

		private final int mOffset; // aka first index
		private final int mCount;
		private final Bundle mExtras;

		private int mPos = -1;

		/**
		* @see PageViewCursor#wrap(Cursor, Bundle)
		*/
		@VisibleForTesting
		public PageViewCursor(Cursor cursor, int offset, int limit) {
		super(cursor);

		checkArgument(offset > -1);
		checkArgument(limit > -1);

		mOffset = offset;

		mExtras = new Bundle();
		Bundle extras = cursor.getExtras();
		if (extras != null) {
		mExtras.putAll(extras);
		}
		mExtras.putBoolean(EXTRA_AUTO_PAGED, true);

		// We need a mutable bundle so we can add QUERY_RESULT_SIZE.
		// Direct equality check is correct here. Bundle.EMPTY is a specific instance
		// of Bundle that is immutable by way of implementation.
		// mExtras = (extras == Bundle.EMPTY) ? new Bundle() : extras;

		// When we're wrapping another cursor, it should not already be "paged".
		checkArgument(!mExtras.containsKey(ContentResolver.EXTRA_TOTAL_SIZE));

		int count = mCursor.getCount();
		mExtras.putInt(ContentResolver.EXTRA_TOTAL_SIZE, count);

		mCount = MathUtils.constrain(count - offset, 0, limit);

		if (DEBUG) Log.d(TAG, "Wrapped cursor"
		+ " offset: " + mOffset
		+ ", limit: " + limit
		+ ", delegate_size: " + count
		+ ", paged_count: " + mCount);
		}

		@Override
		public Bundle getExtras() {
		return mExtras;
		}

		@Override
		public int getPosition() {
		return mPos;
		}

		@Override
		public boolean isBeforeFirst() {
		if (mCount == 0) {
		return true;
		}
		return mPos == -1;
		}

		@Override
		public boolean isAfterLast() {
		if (mCount == 0) {
		return true;
		}
		return mPos == mCount;
		}

		@Override
		public boolean isFirst() {
		return mPos == 0;
		}

		@Override
		public boolean isLast() {
		return mPos == mCount - 1;
		}

		@Override
		public boolean moveToFirst() {
		return moveToPosition(0);
		}

		@Override
		public boolean moveToLast() {
		return moveToPosition(mCount - 1);
		}

		@Override
		public boolean moveToNext() {
		return move(1);
		}

		@Override
		public boolean moveToPrevious() {
		return move(-1);
		}

		@Override
		public boolean move(int offset) {
		return moveToPosition(mPos + offset);
		}

		@Override
		public boolean moveToPosition(int position) {
		if (position >= mCount) {
		if (VERBOSE) Log.v(TAG, "Invalid Positon: " + position + " >= count: " + mCount
		+ ". Moving to last record.");
		mPos = mCount;
		super.moveToPosition(mOffset + mPos); // move into "after last" state.
		return false;
		}

		// Make sure position isn't before the beginning of the cursor
		if (position < 0) {
		if (VERBOSE) Log.v(TAG, "Ignoring invalid move to position: " + position);
		mPos = -1;
		super.moveToPosition(mPos);
		return false;
		}

		if (position == mPos) {
		if (VERBOSE) Log.v(TAG, "Ignoring no-op move to position: " + position);
		return true;
		}

		int delegatePosition = position + mOffset;
		if (VERBOSE) Log.v(TAG, "Moving delegate cursor to position: " + delegatePosition);
		if (super.moveToPosition(delegatePosition)) {
		mPos = position;
		return true;
		} else {
		mPos = -1;
		super.moveToPosition(-1);
		return false;
		}
		}

		@Override
		public boolean onMove(int oldPosition, int newPosition) {
		throw new UnsupportedOperationException("Not supported.");
		}

		@Override
		public int getCount() {
		return mCount;
		}

		/**
		* Wraps the cursor such that it will honor paging args (if present), AND if the cursor
		* does not report paging size.
		*
		* <p>No-op if cursor already contains paging or is less than specified page size.
		*/
		public static Cursor wrap(Cursor cursor, @Nullable Bundle queryArgs) {

		boolean hasPagingArgs =
		queryArgs != null
		&& (queryArgs.containsKey(ContentResolver.QUERY_ARG_OFFSET)
		\|\| queryArgs.containsKey(ContentResolver.QUERY_ARG_LIMIT));

		if (!hasPagingArgs) {
		if (VERBOSE) Log.d(TAG, "No-wrap: No paging args in request.");
		return cursor;
		}

		if (hasPagedResponseDetails(cursor.getExtras())) {
		if (VERBOSE) Log.d(TAG, "No-wrap. Cursor has paging details.");
		return cursor;
		}

		return new PageViewCursor(
		cursor,
		queryArgs.getInt(ContentResolver.QUERY_ARG_OFFSET, 0),
		queryArgs.getInt(ContentResolver.QUERY_ARG_LIMIT, Integer.MAX_VALUE));
		}

		/**
		* @return true if the extras contains information indicating the associated
		* cursor is paged.
		*/
		private static boolean hasPagedResponseDetails(@Nullable Bundle extras) {
		if (extras != null && extras.containsKey(ContentResolver.EXTRA_TOTAL_SIZE)) {
		return true;
		}

		String[] honoredArgs = extras.getStringArray(ContentResolver.EXTRA_HONORED_ARGS);
		if (honoredArgs != null && (
		ArrayUtils.contains(honoredArgs, ContentResolver.QUERY_ARG_OFFSET)
		\|\| ArrayUtils.contains(honoredArgs, ContentResolver.QUERY_ARG_LIMIT))) {
		return true;
		}

		return false;
		}
		}

core/tests/coretests/src/android/database/PageViewCursorTest.java

0 → 100644

+318 −0

Original line number	Diff line number	Diff line
		/*
		* Copyright (C) 2017 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 static org.junit.Assert.assertEquals;
		import static org.junit.Assert.assertFalse;
		import static org.junit.Assert.assertTrue;

		import android.annotation.Nullable;
		import android.content.ContentResolver;
		import android.os.Bundle;
		import android.support.test.runner.AndroidJUnit4;
		import android.util.Log;
		import android.util.MathUtils;

		import com.android.internal.annotations.VisibleForTesting;
		import com.android.internal.util.ArrayUtils;

		import org.junit.Before;
		import org.junit.Test;
		import org.junit.runner.RunWith;

		import java.util.Random;

		@RunWith(AndroidJUnit4.class)
		public class PageViewCursorTest {

		private static final int ITEM_COUNT = 20;

		private static final String NAME_COLUMN = "name";
		private static final String NUM_COLUMN = "num";

		private static final String[] COLUMNS = new String[]{
		NAME_COLUMN,
		NUM_COLUMN
		};

		private static final String[] NAMES = new String[] {
		"000",
		"111",
		"222",
		"333",
		"444",
		"555",
		"666",
		"777",
		"888",
		"999",
		"aaa",
		"bbb",
		"ccc",
		"ddd",
		"eee",
		"fff",
		"ggg",
		"hhh",
		"iii",
		"jjj"
		};

		private MatrixCursor mDelegate;
		private PageViewCursor mCursor;

		@Before
		public void setUp() {
		Random rand = new Random();

		mDelegate = new MatrixCursor(COLUMNS);
		for (int i = 0; i < ITEM_COUNT; i++) {
		MatrixCursor.RowBuilder row = mDelegate.newRow();
		row.add(NAME_COLUMN, NAMES[i]);
		row.add(NUM_COLUMN, rand.nextInt());
		}

		mCursor = new PageViewCursor(mDelegate, 10, 5);
		}

		@Test
		public void testPage_Size() {
		assertEquals(5, mCursor.getCount());
		}

		@Test
		public void testPage_TotalSize() {
		assertEquals(ITEM_COUNT, mCursor.getExtras().getInt(ContentResolver.EXTRA_TOTAL_SIZE));
		}

		@Test
		public void testPage_OffsetExceedsCursorCount_EffectivelyEmptyCursor() {
		mCursor = new PageViewCursor(mDelegate, ITEM_COUNT * 2, 5);
		assertEquals(0, mCursor.getCount());
		}

		@Test
		public void testMoveToPosition() {
		assertTrue(mCursor.moveToPosition(0));
		assertEquals(NAMES[10], mCursor.getString(0));
		assertTrue(mCursor.moveToPosition(1));
		assertEquals(NAMES[11], mCursor.getString(0));
		assertTrue(mCursor.moveToPosition(4));
		assertEquals(NAMES[14], mCursor.getString(0));

		// and then back down again for good measure.
		assertTrue(mCursor.moveToPosition(1));
		assertEquals(NAMES[11], mCursor.getString(0));
		assertTrue(mCursor.moveToPosition(0));
		assertEquals(NAMES[10], mCursor.getString(0));
		}

		@Test
		public void testMoveToPosition_MoveToSamePosition_NoOp() {
		assertTrue(mCursor.moveToPosition(1));
		assertEquals(NAMES[11], mCursor.getString(0));
		assertTrue(mCursor.moveToPosition(1));
		assertEquals(NAMES[11], mCursor.getString(0));
		}

		@Test
		public void testMoveToPosition_PositionOutOfBounds_MovesToBeforeFirst() {
		assertTrue(mCursor.moveToPosition(0));
		assertEquals(NAMES[10], mCursor.getString(0));

		// move before
		assertFalse(mCursor.moveToPosition(-12));
		assertTrue(mCursor.isBeforeFirst());
		}

		@Test
		public void testMoveToPosition_PositionOutOfBounds_MovesToAfterLast() {
		assertTrue(mCursor.moveToPosition(0));
		assertEquals(NAMES[10], mCursor.getString(0));

		assertFalse(mCursor.moveToPosition(222));
		assertTrue(mCursor.isAfterLast());
		}

		@Test
		public void testPosition() {
		assertEquals(-1, mCursor.getPosition());
		}

		@Test
		public void testIsBeforeFirst() {
		assertTrue(mCursor.isBeforeFirst());
		mCursor.moveToFirst();
		assertFalse(mCursor.isBeforeFirst());
		}

		@Test
		public void testCount_ZeroForEmptyCursor() {
		mCursor = new PageViewCursor(mDelegate, 0, 0);
		assertEquals(0, mCursor.getCount());
		}

		@Test
		public void testIsBeforeFirst_TrueForEmptyCursor() {
		mCursor = new PageViewCursor(mDelegate, 0, 0);
		assertTrue(mCursor.isBeforeFirst());
		}

		@Test
		public void testIsAfterLast() {
		assertFalse(mCursor.isAfterLast());
		mCursor.moveToLast();
		mCursor.moveToNext();
		assertTrue(mCursor.isAfterLast());
		}

		@Test
		public void testIsAfterLast_TrueForEmptyCursor() {
		mCursor = new PageViewCursor(mDelegate, 0, 0);
		assertTrue(mCursor.isAfterLast());
		}

		@Test
		public void testIsFirst() {
		assertFalse(mCursor.isFirst());
		mCursor.moveToFirst();
		assertTrue(mCursor.isFirst());
		}

		@Test
		public void testIsLast() {
		assertFalse(mCursor.isLast());
		mCursor.moveToLast();
		assertTrue(mCursor.isLast());
		}

		@Test
		public void testMove() {
		// note that initial position is -1, so moving
		// 2 will only put as at 1.
		mCursor.move(2);
		assertEquals(NAMES[11], mCursor.getString(0));
		mCursor.move(-1);
		assertEquals(NAMES[10], mCursor.getString(0));
		}

		@Test
		public void testMoveToFist() {
		mCursor.moveToPosition(3);
		mCursor.moveToFirst();
		assertEquals(NAMES[10], mCursor.getString(0));
		}

		@Test
		public void testMoveToLast() {
		mCursor.moveToLast();
		assertEquals(NAMES[14], mCursor.getString(0));
		}

		@Test
		public void testMoveToNext() {
		// default position is -1, so next is 0.
		mCursor.moveToNext();
		assertEquals(NAMES[10], mCursor.getString(0));
		}

		@Test
		public void testMoveToNext_AfterLastReturnsFalse() {
		mCursor.moveToLast();
		assertFalse(mCursor.moveToNext());
		}

		@Test
		public void testMoveToPrevious() {
		mCursor.moveToPosition(3);
		mCursor.moveToPrevious();
		assertEquals(NAMES[12], mCursor.getString(0));
		}

		@Test
		public void testMoveToPrevious_BeforeFirstReturnsFalse() {
		assertFalse(mCursor.moveToPrevious());
		}

		@Test
		public void testWindow_ReadPastEnd() {
		assertFalse(mCursor.moveToPosition(10));
		}

		@Test
		public void testOffset_LimitOutOfBounds() {
		mCursor = new PageViewCursor(mDelegate, 5, 100);
		assertEquals(15, mCursor.getCount());
		}

		@Test
		public void testPagingMarker() {
		mCursor = new PageViewCursor(mDelegate, 5, 100);
		assertTrue(mCursor.getExtras().getBoolean(PageViewCursor.EXTRA_AUTO_PAGED));
		}

		@Test
		public void testWrap() {
		Bundle queryArgs = new Bundle();
		queryArgs.putInt(ContentResolver.QUERY_ARG_OFFSET, 5);
		queryArgs.putInt(ContentResolver.QUERY_ARG_LIMIT, 5);
		Cursor wrapped = PageViewCursor.wrap(mDelegate, queryArgs);
		assertTrue(wrapped instanceof PageViewCursor);
		assertEquals(5, wrapped.getCount());
		}

		@Test
		public void testWrap_NoOpWithoutPagingArgs() {
		Cursor wrapped = PageViewCursor.wrap(mDelegate, Bundle.EMPTY);
		assertTrue(mDelegate == wrapped);
		}

		@Test
		public void testWrap_NoOpCursorsWithExistingPaging_ByTotalSize() {
		Bundle extras = new Bundle();
		extras.putInt(ContentResolver.EXTRA_TOTAL_SIZE, 5);
		mDelegate.setExtras(extras);

		Bundle queryArgs = new Bundle();
		queryArgs.putInt(ContentResolver.QUERY_ARG_OFFSET, 5);
		queryArgs.putInt(ContentResolver.QUERY_ARG_LIMIT, 5);
		Cursor wrapped = PageViewCursor.wrap(mDelegate, queryArgs);
		assertTrue(mDelegate == wrapped);
		}

		@Test
		public void testWrap_NoOpCursorsWithExistingPaging_ByHonoredArgs() {
		Bundle extras = new Bundle();
		extras.putStringArray(
		ContentResolver.EXTRA_HONORED_ARGS,
		new String[] {
		ContentResolver.QUERY_ARG_OFFSET,
		ContentResolver.QUERY_ARG_LIMIT
		});
		mDelegate.setExtras(extras);

		Bundle queryArgs = new Bundle();
		queryArgs.putInt(ContentResolver.QUERY_ARG_OFFSET, 5);
		queryArgs.putInt(ContentResolver.QUERY_ARG_LIMIT, 5);
		Cursor wrapped = PageViewCursor.wrap(mDelegate, queryArgs);
		assertTrue(mDelegate == wrapped);
		}

		private void assertStringAt(int row, int column, String expected) {
		mCursor.moveToPosition(row);
		assertEquals(expected, mCursor.getString(column));
		}
		}