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Commit f442477a authored by Hans Boehm's avatar Hans Boehm
Browse files

Clean up database access operations 

Bug: 33251173

Move write and erase operations to a background thread.

Fix interrupt handling during database initialization. Simplify
initialization synchronization.

Initialize a Cursor at startup and use it for most read operations.
Continue to perform accesses on negative indices directly, if they
would miss the CursorWindow. This avoids a somewhat likely situation
in which we're bounding between windows.

Add some code to gracefully degrade in the event of a database failure.
This is currently disabled.

Test: The alternate direct read path was minimally tested by temporarily
modifying the code. Manual tests were run.

Change-Id: I2112f73ca43cc5f855da98d7f9b1c3beaed3f610
parent 2976d21d

src/com/android/calculator2/CalculatorExpr.java

+17 −0
Original line number Diff line number Diff line
@@ -22,8 +22,10 @@ import android.text.SpannableStringBuilder; 
import android.text.Spanned;

import android.text.style.TtsSpan;



import java.io.ByteArrayOutputStream;

import java.io.DataInput;

import java.io.DataOutput;

import java.io.DataOutputStream;

import java.io.IOException;

import java.math.BigInteger;

import java.util.ArrayList;
@@ -411,6 +413,21 @@ class CalculatorExpr { 
        }

    }



    /**

     * Use write() above to generate a byte array containing a serialized representation of

     * this expression.

     */

    public byte[] toBytes() {

        ByteArrayOutputStream byteArrayStream = new ByteArrayOutputStream();

        try (DataOutputStream out = new DataOutputStream(byteArrayStream)) {

            write(out);

        } catch (IOException e) {

            // Impossible; No IO involved.

            throw new AssertionError("Impossible IO exception", e);

        }

        return byteArrayStream.toByteArray();

    }



    /**

     * Does this expression end with a numeric constant?

     * As opposed to an operator or preevaluated expression.

src/com/android/calculator2/Evaluator.java

+1 −9
Original line number Diff line number Diff line
@@ -1407,15 +1407,7 @@ public class Evaluator implements CalculatorExpr.ExprResolver { 
     * If in_history is true, add it with a positive index, so it will appear in the history.

     */

    private long addToDB(boolean in_history, ExprInfo ei) {

        /* TODO: Possibly do this in a different thread. */

        ByteArrayOutputStream byteArrayStream = new ByteArrayOutputStream();

        try (DataOutputStream out = new DataOutputStream(byteArrayStream)) {

            ei.mExpr.write(out);

        } catch (IOException e) {

            // Impossible; No IO involved.

            throw new AssertionError("Impossible IO exception", e);

        }

        byte[] serializedExpr = byteArrayStream.toByteArray();

        byte[] serializedExpr = ei.mExpr.toBytes();

        ExpressionDB.RowData rd = new ExpressionDB.RowData(serializedExpr, ei.mDegreeMode,

                ei.mLongTimeout, 0);

        long resultIndex = mExprDB.addRow(!in_history, rd);