Merge "Optimize fillWindow to improve reverse-seek performance. Bug: 5520301" (90c487f0) · Commits · e / os / android_frameworks_base

core/java/android/database/BulkCursorNative.java

+2 −2

Original line number	Diff line number	Diff line
		@@ -180,13 +180,13 @@ final class BulkCursorProxy implements IBulkCursor {
		return mRemote;
		}

		public CursorWindow getWindow(int startPos) throws RemoteException
		public CursorWindow getWindow(int position) throws RemoteException
		{
		Parcel data = Parcel.obtain();
		Parcel reply = Parcel.obtain();
		try {
		data.writeInterfaceToken(IBulkCursor.descriptor);
		data.writeInt(startPos);
		data.writeInt(position);

		mRemote.transact(GET_CURSOR_WINDOW_TRANSACTION, data, reply, 0);
		DatabaseUtils.readExceptionFromParcel(reply);

core/java/android/database/CursorToBulkCursorAdaptor.java

+5 −6

Original line number	Diff line number	Diff line
		@@ -132,11 +132,11 @@ public final class CursorToBulkCursorAdaptor extends BulkCursorNative
		}

		@Override
		public CursorWindow getWindow(int startPos) {
		public CursorWindow getWindow(int position) {
		synchronized (mLock) {
		throwIfCursorIsClosed();

		if (!mCursor.moveToPosition(startPos)) {
		if (!mCursor.moveToPosition(position)) {
		closeFilledWindowLocked();
		return null;
		}
		@@ -149,12 +149,11 @@ public final class CursorToBulkCursorAdaptor extends BulkCursorNative
		if (window == null) {
		mFilledWindow = new CursorWindow(mProviderName);
		window = mFilledWindow;
		mCursor.fillWindow(startPos, window);
		} else if (startPos < window.getStartPosition()
		\|\| startPos >= window.getStartPosition() + window.getNumRows()) {
		} else if (position < window.getStartPosition()
		\|\| position >= window.getStartPosition() + window.getNumRows()) {
		window.clear();
		mCursor.fillWindow(startPos, window);
		}
		mCursor.fillWindow(position, window);
		}

		// Acquire a reference before returning from this RPC.

core/java/android/database/CursorWindow.java

+18 −0

Original line number	Diff line number	Diff line
		@@ -55,6 +55,7 @@ public class CursorWindow extends SQLiteClosable implements Parcelable {
		public int mWindowPtr;

		private int mStartPos;
		private final String mName;

		private final CloseGuard mCloseGuard = CloseGuard.get();

		@@ -84,6 +85,8 @@ public class CursorWindow extends SQLiteClosable implements Parcelable {
		private static native boolean nativePutDouble(int windowPtr, double value, int row, int column);
		private static native boolean nativePutNull(int windowPtr, int row, int column);

		private static native String nativeGetName(int windowPtr);

		/**
		* Creates a new empty cursor window and gives it a name.
		* <p>
		@@ -95,6 +98,7 @@ public class CursorWindow extends SQLiteClosable implements Parcelable {
		*/
		public CursorWindow(String name) {
		mStartPos = 0;
		mName = name;
		mWindowPtr = nativeCreate(name, sCursorWindowSize);
		if (mWindowPtr == 0) {
		throw new CursorWindowAllocationException("Cursor window allocation of " +
		@@ -129,6 +133,7 @@ public class CursorWindow extends SQLiteClosable implements Parcelable {
		throw new CursorWindowAllocationException("Cursor window could not be "
		+ "created from binder.");
		}
		mName = nativeGetName(mWindowPtr);
		mCloseGuard.open("close");
		}

		@@ -155,6 +160,14 @@ public class CursorWindow extends SQLiteClosable implements Parcelable {
		}
		}

		/**
		* Gets the name of this cursor window.
		* @hide
		*/
		public String getName() {
		return mName;
		}

		/**
		* Closes the cursor window and frees its underlying resources when all other
		* remaining references have been released.
		@@ -758,4 +771,9 @@ public class CursorWindow extends SQLiteClosable implements Parcelable {
		String s = (buff.length() > 980) ? buff.substring(0, 980) : buff.toString();
		return "# Open Cursors=" + total + s;
		}

		@Override
		public String toString() {
		return getName() + " {" + Integer.toHexString(mWindowPtr) + "}";
		}
		}

core/java/android/database/DatabaseUtils.java

+26 −0

Original line number	Diff line number	Diff line
		@@ -725,6 +725,32 @@ public class DatabaseUtils {
		}
		}

		/**
		* Picks a start position for {@link Cursor#fillWindow} such that the
		* window will contain the requested row and a useful range of rows
		* around it.
		*
		* When the data set is too large to fit in a cursor window, seeking the
		* cursor can become a very expensive operation since we have to run the
		* query again when we move outside the bounds of the current window.
		*
		* We try to choose a start position for the cursor window such that
		* 1/3 of the window's capacity is used to hold rows before the requested
		* position and 2/3 of the window's capacity is used to hold rows after the
		* requested position.
		*
		* @param cursorPosition The row index of the row we want to get.
		* @param cursorWindowCapacity The estimated number of rows that can fit in
		* a cursor window, or 0 if unknown.
		* @return The recommended start position, always less than or equal to
		* the requested row.
		* @hide
		*/
		public static int cursorPickFillWindowStartPosition(
		int cursorPosition, int cursorWindowCapacity) {
		return Math.max(cursorPosition - cursorWindowCapacity / 3, 0);
		}

		/**
		* Query the table for the number of rows in the table.
		* @param db the database the table is in

core/java/android/database/IBulkCursor.java

+9 −3

Original line number	Diff line number	Diff line
		@@ -30,11 +30,17 @@ import android.os.RemoteException;
		*/
		public interface IBulkCursor extends IInterface {
		/**
		* Returns a BulkCursorWindow, which either has a reference to a shared
		* memory segment with the rows, or an array of JSON strings.
		* Gets a cursor window that contains the specified position.
		* The window will contain a range of rows around the specified position.
		*/
		public CursorWindow getWindow(int startPos) throws RemoteException;
		public CursorWindow getWindow(int position) throws RemoteException;

		/**
		* Notifies the cursor that the position has changed.
		* Only called when {@link #getWantsAllOnMoveCalls()} returns true.
		*
		* @param position The new position
		*/
		public void onMove(int position) throws RemoteException;

		/**