Android example source code file (SQLiteDatabase.java)

This example Android source code file (SQLiteDatabase.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Android by Example" ^TM.

Java - Android tags/keywords

android, arraylist, contentvalues, cursor, cursorfactory, database, illegalstateexception, object, os, pragma, sqlexception, sqlitedatabase, sqlitedatabasecorruptexception, sqlitestatement, string, stringbuilder, syncupdateinfo, util, utilities, utils

The SQLiteDatabase.java Android example source code

/*
 * 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.sqlite;

import com.google.android.collect.Maps;

import android.app.ActivityThread;
import android.content.ContentValues;
import android.database.Cursor;
import android.database.DatabaseUtils;
import android.database.SQLException;
import android.database.sqlite.SQLiteDebug.DbStats;
import android.os.Debug;
import android.os.SystemClock;
import android.os.SystemProperties;
import android.text.TextUtils;
import android.util.Config;
import android.util.EventLog;
import android.util.Log;
import android.util.Pair;

import java.io.File;
import java.lang.ref.WeakReference;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Locale;
import java.util.Map;
import java.util.Random;
import java.util.Set;
import java.util.WeakHashMap;
import java.util.concurrent.locks.ReentrantLock;
import java.util.regex.Pattern;

/**
 * Exposes methods to manage a SQLite database.
 * <p>SQLiteDatabase has methods to create, delete, execute SQL commands, and
 * perform other common database management tasks.
 * <p>See the Notepad sample application in the SDK for an example of creating
 * and managing a database.
 * <p> Database names must be unique within an application, not across all
 * applications.
 *
 * <h3>Localized Collation - ORDER BY
 * <p>In addition to SQLite's default BINARY collator, Android supplies
 * two more, <code>LOCALIZED, which changes with the system's current locale
 * if you wire it up correctly (XXX a link needed!), and <code>UNICODE, which
 * is the Unicode Collation Algorithm and not tailored to the current locale.
 */
public class SQLiteDatabase extends SQLiteClosable {
    private static final String TAG = "Database";
    private static final int EVENT_DB_OPERATION = 52000;
    private static final int EVENT_DB_CORRUPT = 75004;

    /**
     * Algorithms used in ON CONFLICT clause
     * http://www.sqlite.org/lang_conflict.html
     */
    /**
     *  When a constraint violation occurs, an immediate ROLLBACK occurs,
     * thus ending the current transaction, and the command aborts with a
     * return code of SQLITE_CONSTRAINT. If no transaction is active
     * (other than the implied transaction that is created on every command)
     *  then this algorithm works the same as ABORT.
     */
    public static final int CONFLICT_ROLLBACK = 1;

    /**
     * When a constraint violation occurs,no ROLLBACK is executed
     * so changes from prior commands within the same transaction
     * are preserved. This is the default behavior.
     */
    public static final int CONFLICT_ABORT = 2;

    /**
     * When a constraint violation occurs, the command aborts with a return
     * code SQLITE_CONSTRAINT. But any changes to the database that
     * the command made prior to encountering the constraint violation
     * are preserved and are not backed out.
     */
    public static final int CONFLICT_FAIL = 3;

    /**
     * When a constraint violation occurs, the one row that contains
     * the constraint violation is not inserted or changed.
     * But the command continues executing normally. Other rows before and
     * after the row that contained the constraint violation continue to be
     * inserted or updated normally. No error is returned.
     */
    public static final int CONFLICT_IGNORE = 4;

    /**
     * When a UNIQUE constraint violation occurs, the pre-existing rows that
     * are causing the constraint violation are removed prior to inserting
     * or updating the current row. Thus the insert or update always occurs.
     * The command continues executing normally. No error is returned.
     * If a NOT NULL constraint violation occurs, the NULL value is replaced
     * by the default value for that column. If the column has no default
     * value, then the ABORT algorithm is used. If a CHECK constraint
     * violation occurs then the IGNORE algorithm is used. When this conflict
     * resolution strategy deletes rows in order to satisfy a constraint,
     * it does not invoke delete triggers on those rows.
     *  This behavior might change in a future release.
     */
    public static final int CONFLICT_REPLACE = 5;

    /**
     * use the following when no conflict action is specified.
     */
    public static final int CONFLICT_NONE = 0;
    private static final String[] CONFLICT_VALUES = new String[]
            {"", " OR ROLLBACK ", " OR ABORT ", " OR FAIL ", " OR IGNORE ", " OR REPLACE "};

    /**
     * Maximum Length Of A LIKE Or GLOB Pattern
     * The pattern matching algorithm used in the default LIKE and GLOB implementation
     * of SQLite can exhibit O(N^2) performance (where N is the number of characters in
     * the pattern) for certain pathological cases. To avoid denial-of-service attacks
     * the length of the LIKE or GLOB pattern is limited to SQLITE_MAX_LIKE_PATTERN_LENGTH bytes.
     * The default value of this limit is 50000. A modern workstation can evaluate
     * even a pathological LIKE or GLOB pattern of 50000 bytes relatively quickly.
     * The denial of service problem only comes into play when the pattern length gets
     * into millions of bytes. Nevertheless, since most useful LIKE or GLOB patterns
     * are at most a few dozen bytes in length, paranoid application developers may
     * want to reduce this parameter to something in the range of a few hundred
     * if they know that external users are able to generate arbitrary patterns.
     */
    public static final int SQLITE_MAX_LIKE_PATTERN_LENGTH = 50000;

    /**
     * Flag for {@link #openDatabase} to open the database for reading and writing.
     * If the disk is full, this may fail even before you actually write anything.
     *
     * {@more} Note that the value of this flag is 0, so it is the default.
     */
    public static final int OPEN_READWRITE = 0x00000000;          // update native code if changing

    /**
     * Flag for {@link #openDatabase} to open the database for reading only.
     * This is the only reliable way to open a database if the disk may be full.
     */
    public static final int OPEN_READONLY = 0x00000001;           // update native code if changing

    private static final int OPEN_READ_MASK = 0x00000001;         // update native code if changing

    /**
     * Flag for {@link #openDatabase} to open the database without support for localized collators.
     *
     * {@more} This causes the collator <code>LOCALIZED not to be created.
     * You must be consistent when using this flag to use the setting the database was
     * created with.  If this is set, {@link #setLocale} will do nothing.
     */
    public static final int NO_LOCALIZED_COLLATORS = 0x00000010;  // update native code if changing

    /**
     * Flag for {@link #openDatabase} to create the database file if it does not already exist.
     */
    public static final int CREATE_IF_NECESSARY = 0x10000000;     // update native code if changing

    /**
     * Indicates whether the most-recently started transaction has been marked as successful.
     */
    private boolean mInnerTransactionIsSuccessful;

    /**
     * Valid during the life of a transaction, and indicates whether the entire transaction (the
     * outer one and all of the inner ones) so far has been successful.
     */
    private boolean mTransactionIsSuccessful;

    /**
     * Valid during the life of a transaction.
     */
    private SQLiteTransactionListener mTransactionListener;

    /** Synchronize on this when accessing the database */
    private final ReentrantLock mLock = new ReentrantLock(true);

    private long mLockAcquiredWallTime = 0L;
    private long mLockAcquiredThreadTime = 0L;

    // limit the frequency of complaints about each database to one within 20 sec
    // unless run command adb shell setprop log.tag.Database VERBOSE
    private static final int LOCK_WARNING_WINDOW_IN_MS = 20000;
    /** If the lock is held this long then a warning will be printed when it is released. */
    private static final int LOCK_ACQUIRED_WARNING_TIME_IN_MS = 300;
    private static final int LOCK_ACQUIRED_WARNING_THREAD_TIME_IN_MS = 100;
    private static final int LOCK_ACQUIRED_WARNING_TIME_IN_MS_ALWAYS_PRINT = 2000;

    private static final int SLEEP_AFTER_YIELD_QUANTUM = 1000;

    // The pattern we remove from database filenames before
    // potentially logging them.
    private static final Pattern EMAIL_IN_DB_PATTERN = Pattern.compile("[\\w\\.\\-]+@[\\w\\.\\-]+");

    private long mLastLockMessageTime = 0L;

    // Things related to query logging/sampling for debugging
    // slow/frequent queries during development.  Always log queries
    // which take (by default) 500ms+; shorter queries are sampled
    // accordingly.  Commit statements, which are typically slow, are
    // logged together with the most recently executed SQL statement,
    // for disambiguation.  The 500ms value is configurable via a
    // SystemProperty, but developers actively debugging database I/O
    // should probably use the regular log tunable,
    // LOG_SLOW_QUERIES_PROPERTY, defined below.
    private static int sQueryLogTimeInMillis = 0;  // lazily initialized
    private static final int QUERY_LOG_SQL_LENGTH = 64;
    private static final String COMMIT_SQL = "COMMIT;";
    private final Random mRandom = new Random();
    private String mLastSqlStatement = null;

    // String prefix for slow database query EventLog records that show
    // lock acquistions of the database.
    /* package */ static final String GET_LOCK_LOG_PREFIX = "GETLOCK:";

    /** Used by native code, do not rename */
    /* package */ int mNativeHandle = 0;

    /** Used to make temp table names unique */
    /* package */ int mTempTableSequence = 0;

    /** The path for the database file */
    private String mPath;

    /** The anonymized path for the database file for logging purposes */
    private String mPathForLogs = null;  // lazily populated

    /** The flags passed to open/create */
    private int mFlags;

    /** The optional factory to use when creating new Cursors */
    private CursorFactory mFactory;

    private WeakHashMap<SQLiteClosable, Object> mPrograms;

    /**
     * for each instance of this class, a cache is maintained to store
     * the compiled query statement ids returned by sqlite database.
     *     key = sql statement with "?" for bind args
     *     value = {@link SQLiteCompiledSql}
     * If an application opens the database and keeps it open during its entire life, then
     * there will not be an overhead of compilation of sql statements by sqlite.
     *
     * why is this cache NOT static? because sqlite attaches compiledsql statements to the
     * struct created when {@link SQLiteDatabase#openDatabase(String, CursorFactory, int)} is
     * invoked.
     *
     * this cache has an upper limit of mMaxSqlCacheSize (settable by calling the method
     * (@link setMaxCacheSize(int)}). its default is 0 - i.e., no caching by default because
     * most of the apps don't use "?" syntax in their sql, caching is not useful for them.
     */
    /* package */ Map<String, SQLiteCompiledSql> mCompiledQueries = Maps.newHashMap();
    /**
     * @hide
     */
    public static final int MAX_SQL_CACHE_SIZE = 250;
    private int mMaxSqlCacheSize = MAX_SQL_CACHE_SIZE; // max cache size per Database instance
    private int mCacheFullWarnings;
    private static final int MAX_WARNINGS_ON_CACHESIZE_CONDITION = 1;

    /** maintain stats about number of cache hits and misses */
    private int mNumCacheHits;
    private int mNumCacheMisses;

    /** the following 2 members maintain the time when a database is opened and closed */
    private String mTimeOpened = null;
    private String mTimeClosed = null;

    /** Used to find out where this object was created in case it never got closed. */
    private Throwable mStackTrace = null;

    // System property that enables logging of slow queries. Specify the threshold in ms.
    private static final String LOG_SLOW_QUERIES_PROPERTY = "db.log.slow_query_threshold";
    private final int mSlowQueryThreshold;

    /**
     * @param closable
     */
    void addSQLiteClosable(SQLiteClosable closable) {
        lock();
        try {
            mPrograms.put(closable, null);
        } finally {
            unlock();
        }
    }

    void removeSQLiteClosable(SQLiteClosable closable) {
        lock();
        try {
            mPrograms.remove(closable);
        } finally {
            unlock();
        }
    }

    @Override
    protected void onAllReferencesReleased() {
        if (isOpen()) {
            if (SQLiteDebug.DEBUG_SQL_CACHE) {
                mTimeClosed = getTime();
            }
            dbclose();
        }
    }

    /**
     * Attempts to release memory that SQLite holds but does not require to
     * operate properly. Typically this memory will come from the page cache.
     *
     * @return the number of bytes actually released
     */
    static public native int releaseMemory();

    /**
     * Control whether or not the SQLiteDatabase is made thread-safe by using locks
     * around critical sections. This is pretty expensive, so if you know that your
     * DB will only be used by a single thread then you should set this to false.
     * The default is true.
     * @param lockingEnabled set to true to enable locks, false otherwise
     */
    public void setLockingEnabled(boolean lockingEnabled) {
        mLockingEnabled = lockingEnabled;
    }

    /**
     * If set then the SQLiteDatabase is made thread-safe by using locks
     * around critical sections
     */
    private boolean mLockingEnabled = true;

    /* package */ void onCorruption() {
        Log.e(TAG, "Removing corrupt database: " + mPath);
        EventLog.writeEvent(EVENT_DB_CORRUPT, mPath);
        try {
            // Close the database (if we can), which will cause subsequent operations to fail.
            close();
        } finally {
            // Delete the corrupt file.  Don't re-create it now -- that would just confuse people
            // -- but the next time someone tries to open it, they can set it up from scratch.
            if (!mPath.equalsIgnoreCase(":memory")) {
                // delete is only for non-memory database files
                new File(mPath).delete();
            }
        }
    }

    /**
     * Locks the database for exclusive access. The database lock must be held when
     * touch the native sqlite3* object since it is single threaded and uses
     * a polling lock contention algorithm. The lock is recursive, and may be acquired
     * multiple times by the same thread. This is a no-op if mLockingEnabled is false.
     *
     * @see #unlock()
     */
    /* package */ void lock() {
        if (!mLockingEnabled) return;
        mLock.lock();
        if (SQLiteDebug.DEBUG_LOCK_TIME_TRACKING) {
            if (mLock.getHoldCount() == 1) {
                // Use elapsed real-time since the CPU may sleep when waiting for IO
                mLockAcquiredWallTime = SystemClock.elapsedRealtime();
                mLockAcquiredThreadTime = Debug.threadCpuTimeNanos();
            }
        }
    }

    /**
     * Locks the database for exclusive access. The database lock must be held when
     * touch the native sqlite3* object since it is single threaded and uses
     * a polling lock contention algorithm. The lock is recursive, and may be acquired
     * multiple times by the same thread.
     *
     * @see #unlockForced()
     */
    private void lockForced() {
        mLock.lock();
        if (SQLiteDebug.DEBUG_LOCK_TIME_TRACKING) {
            if (mLock.getHoldCount() == 1) {
                // Use elapsed real-time since the CPU may sleep when waiting for IO
                mLockAcquiredWallTime = SystemClock.elapsedRealtime();
                mLockAcquiredThreadTime = Debug.threadCpuTimeNanos();
            }
        }
    }

    /**
     * Releases the database lock. This is a no-op if mLockingEnabled is false.
     *
     * @see #unlock()
     */
    /* package */ void unlock() {
        if (!mLockingEnabled) return;
        if (SQLiteDebug.DEBUG_LOCK_TIME_TRACKING) {
            if (mLock.getHoldCount() == 1) {
                checkLockHoldTime();
            }
        }
        mLock.unlock();
    }

    /**
     * Releases the database lock.
     *
     * @see #unlockForced()
     */
    private void unlockForced() {
        if (SQLiteDebug.DEBUG_LOCK_TIME_TRACKING) {
            if (mLock.getHoldCount() == 1) {
                checkLockHoldTime();
            }
        }
        mLock.unlock();
    }

    private void checkLockHoldTime() {
        // Use elapsed real-time since the CPU may sleep when waiting for IO
        long elapsedTime = SystemClock.elapsedRealtime();
        long lockedTime = elapsedTime - mLockAcquiredWallTime;
        if (lockedTime < LOCK_ACQUIRED_WARNING_TIME_IN_MS_ALWAYS_PRINT &&
                !Log.isLoggable(TAG, Log.VERBOSE) &&
                (elapsedTime - mLastLockMessageTime) < LOCK_WARNING_WINDOW_IN_MS) {
            return;
        }
        if (lockedTime > LOCK_ACQUIRED_WARNING_TIME_IN_MS) {
            int threadTime = (int)
                    ((Debug.threadCpuTimeNanos() - mLockAcquiredThreadTime) / 1000000);
            if (threadTime > LOCK_ACQUIRED_WARNING_THREAD_TIME_IN_MS ||
                    lockedTime > LOCK_ACQUIRED_WARNING_TIME_IN_MS_ALWAYS_PRINT) {
                mLastLockMessageTime = elapsedTime;
                String msg = "lock held on " + mPath + " for " + lockedTime + "ms. Thread time was "
                        + threadTime + "ms";
                if (SQLiteDebug.DEBUG_LOCK_TIME_TRACKING_STACK_TRACE) {
                    Log.d(TAG, msg, new Exception());
                } else {
                    Log.d(TAG, msg);
                }
            }
        }
    }

    /**
     * Begins a transaction. Transactions can be nested. When the outer transaction is ended all of
     * the work done in that transaction and all of the nested transactions will be committed or
     * rolled back. The changes will be rolled back if any transaction is ended without being
     * marked as clean (by calling setTransactionSuccessful). Otherwise they will be committed.
     *
     * <p>Here is the standard idiom for transactions:
     *
     * <pre>
     *   db.beginTransaction();
     *   try {
     *     ...
     *     db.setTransactionSuccessful();
     *   } finally {
     *     db.endTransaction();
     *   }
     * </pre>
     */
    public void beginTransaction() {
        beginTransactionWithListener(null /* transactionStatusCallback */);
    }

    /**
     * Begins a transaction. Transactions can be nested. When the outer transaction is ended all of
     * the work done in that transaction and all of the nested transactions will be committed or
     * rolled back. The changes will be rolled back if any transaction is ended without being
     * marked as clean (by calling setTransactionSuccessful). Otherwise they will be committed.
     *
     * <p>Here is the standard idiom for transactions:
     *
     * <pre>
     *   db.beginTransactionWithListener(listener);
     *   try {
     *     ...
     *     db.setTransactionSuccessful();
     *   } finally {
     *     db.endTransaction();
     *   }
     * </pre>
     * @param transactionListener listener that should be notified when the transaction begins,
     * commits, or is rolled back, either explicitly or by a call to
     * {@link #yieldIfContendedSafely}.
     */
    public void beginTransactionWithListener(SQLiteTransactionListener transactionListener) {
        lockForced();
        if (!isOpen()) {
            throw new IllegalStateException("database not open");
        }
        boolean ok = false;
        try {
            // If this thread already had the lock then get out
            if (mLock.getHoldCount() > 1) {
                if (mInnerTransactionIsSuccessful) {
                    String msg = "Cannot call beginTransaction between "
                            + "calling setTransactionSuccessful and endTransaction";
                    IllegalStateException e = new IllegalStateException(msg);
                    Log.e(TAG, "beginTransaction() failed", e);
                    throw e;
                }
                ok = true;
                return;
            }

            // This thread didn't already have the lock, so begin a database
            // transaction now.
            execSQL("BEGIN EXCLUSIVE;");
            mTransactionListener = transactionListener;
            mTransactionIsSuccessful = true;
            mInnerTransactionIsSuccessful = false;
            if (transactionListener != null) {
                try {
                    transactionListener.onBegin();
                } catch (RuntimeException e) {
                    execSQL("ROLLBACK;");
                    throw e;
                }
            }
            ok = true;
        } finally {
            if (!ok) {
                // beginTransaction is called before the try block so we must release the lock in
                // the case of failure.
                unlockForced();
            }
        }
    }

    /**
     * End a transaction. See beginTransaction for notes about how to use this and when transactions
     * are committed and rolled back.
     */
    public void endTransaction() {
        if (!isOpen()) {
            throw new IllegalStateException("database not open");
        }
        if (!mLock.isHeldByCurrentThread()) {
            throw new IllegalStateException("no transaction pending");
        }
        try {
            if (mInnerTransactionIsSuccessful) {
                mInnerTransactionIsSuccessful = false;
            } else {
                mTransactionIsSuccessful = false;
            }
            if (mLock.getHoldCount() != 1) {
                return;
            }
            RuntimeException savedException = null;
            if (mTransactionListener != null) {
                try {
                    if (mTransactionIsSuccessful) {
                        mTransactionListener.onCommit();
                    } else {
                        mTransactionListener.onRollback();
                    }
                } catch (RuntimeException e) {
                    savedException = e;
                    mTransactionIsSuccessful = false;
                }
            }
            if (mTransactionIsSuccessful) {
                execSQL(COMMIT_SQL);
            } else {
                try {
                    execSQL("ROLLBACK;");
                    if (savedException != null) {
                        throw savedException;
                    }
                } catch (SQLException e) {
                    if (Config.LOGD) {
                        Log.d(TAG, "exception during rollback, maybe the DB previously "
                                + "performed an auto-rollback");
                    }
                }
            }
        } finally {
            mTransactionListener = null;
            unlockForced();
            if (Config.LOGV) {
                Log.v(TAG, "unlocked " + Thread.currentThread()
                        + ", holdCount is " + mLock.getHoldCount());
            }
        }
    }

    /**
     * Marks the current transaction as successful. Do not do any more database work between
     * calling this and calling endTransaction. Do as little non-database work as possible in that
     * situation too. If any errors are encountered between this and endTransaction the transaction
     * will still be committed.
     *
     * @throws IllegalStateException if the current thread is not in a transaction or the
     * transaction is already marked as successful.
     */
    public void setTransactionSuccessful() {
        if (!isOpen()) {
            throw new IllegalStateException("database not open");
        }
        if (!mLock.isHeldByCurrentThread()) {
            throw new IllegalStateException("no transaction pending");
        }
        if (mInnerTransactionIsSuccessful) {
            throw new IllegalStateException(
                    "setTransactionSuccessful may only be called once per call to beginTransaction");
        }
        mInnerTransactionIsSuccessful = true;
    }

    /**
     * return true if there is a transaction pending
     */
    public boolean inTransaction() {
        return mLock.getHoldCount() > 0;
    }

    /**
     * Checks if the database lock is held by this thread.
     *
     * @return true, if this thread is holding the database lock.
     */
    public boolean isDbLockedByCurrentThread() {
        return mLock.isHeldByCurrentThread();
    }

    /**
     * Checks if the database is locked by another thread. This is
     * just an estimate, since this status can change at any time,
     * including after the call is made but before the result has
     * been acted upon.
     *
     * @return true, if the database is locked by another thread
     */
    public boolean isDbLockedByOtherThreads() {
        return !mLock.isHeldByCurrentThread() && mLock.isLocked();
    }

    /**
     * Temporarily end the transaction to let other threads run. The transaction is assumed to be
     * successful so far. Do not call setTransactionSuccessful before calling this. When this
     * returns a new transaction will have been created but not marked as successful.
     * @return true if the transaction was yielded
     * @deprecated if the db is locked more than once (becuase of nested transactions) then the lock
     *   will not be yielded. Use yieldIfContendedSafely instead.
     */
    @Deprecated
    public boolean yieldIfContended() {
        return yieldIfContendedHelper(false /* do not check yielding */,
                -1 /* sleepAfterYieldDelay */);
    }

    /**
     * Temporarily end the transaction to let other threads run. The transaction is assumed to be
     * successful so far. Do not call setTransactionSuccessful before calling this. When this
     * returns a new transaction will have been created but not marked as successful. This assumes
     * that there are no nested transactions (beginTransaction has only been called once) and will
     * throw an exception if that is not the case.
     * @return true if the transaction was yielded
     */
    public boolean yieldIfContendedSafely() {
        return yieldIfContendedHelper(true /* check yielding */, -1 /* sleepAfterYieldDelay*/);
    }

    /**
     * Temporarily end the transaction to let other threads run. The transaction is assumed to be
     * successful so far. Do not call setTransactionSuccessful before calling this. When this
     * returns a new transaction will have been created but not marked as successful. This assumes
     * that there are no nested transactions (beginTransaction has only been called once) and will
     * throw an exception if that is not the case.
     * @param sleepAfterYieldDelay if > 0, sleep this long before starting a new transaction if
     *   the lock was actually yielded. This will allow other background threads to make some
     *   more progress than they would if we started the transaction immediately.
     * @return true if the transaction was yielded
     */
    public boolean yieldIfContendedSafely(long sleepAfterYieldDelay) {
        return yieldIfContendedHelper(true /* check yielding */, sleepAfterYieldDelay);
    }

    private boolean yieldIfContendedHelper(boolean checkFullyYielded, long sleepAfterYieldDelay) {
        if (mLock.getQueueLength() == 0) {
            // Reset the lock acquire time since we know that the thread was willing to yield
            // the lock at this time.
            mLockAcquiredWallTime = SystemClock.elapsedRealtime();
            mLockAcquiredThreadTime = Debug.threadCpuTimeNanos();
            return false;
        }
        setTransactionSuccessful();
        SQLiteTransactionListener transactionListener = mTransactionListener;
        endTransaction();
        if (checkFullyYielded) {
            if (this.isDbLockedByCurrentThread()) {
                throw new IllegalStateException(
                        "Db locked more than once. yielfIfContended cannot yield");
            }
        }
        if (sleepAfterYieldDelay > 0) {
            // Sleep for up to sleepAfterYieldDelay milliseconds, waking up periodically to
            // check if anyone is using the database.  If the database is not contended,
            // retake the lock and return.
            long remainingDelay = sleepAfterYieldDelay;
            while (remainingDelay > 0) {
                try {
                    Thread.sleep(remainingDelay < SLEEP_AFTER_YIELD_QUANTUM ?
                            remainingDelay : SLEEP_AFTER_YIELD_QUANTUM);
                } catch (InterruptedException e) {
                    Thread.interrupted();
                }
                remainingDelay -= SLEEP_AFTER_YIELD_QUANTUM;
                if (mLock.getQueueLength() == 0) {
                    break;
                }
            }
        }
        beginTransactionWithListener(transactionListener);
        return true;
    }

    /** Maps table names to info about what to which _sync_time column to set
     * to NULL on an update. This is used to support syncing. */
    private final Map<String, SyncUpdateInfo> mSyncUpdateInfo =
            new HashMap<String, SyncUpdateInfo>();

    public Map<String, String> getSyncedTables() {
        synchronized(mSyncUpdateInfo) {
            HashMap<String, String> tables = new HashMap();
            for (String table : mSyncUpdateInfo.keySet()) {
                SyncUpdateInfo info = mSyncUpdateInfo.get(table);
                if (info.deletedTable != null) {
                    tables.put(table, info.deletedTable);
                }
            }
            return tables;
        }
    }

    /**
     * Internal class used to keep track what needs to be marked as changed
     * when an update occurs. This is used for syncing, so the sync engine
     * knows what data has been updated locally.
     */
    static private class SyncUpdateInfo {
        /**
         * Creates the SyncUpdateInfo class.
         *
         * @param masterTable The table to set _sync_time to NULL in
         * @param deletedTable The deleted table that corresponds to the
         *          master table
         * @param foreignKey The key that refers to the primary key in table
         */
        SyncUpdateInfo(String masterTable, String deletedTable,
                String foreignKey) {
            this.masterTable = masterTable;
            this.deletedTable = deletedTable;
            this.foreignKey = foreignKey;
        }

        /** The table containing the _sync_time column */
        String masterTable;

        /** The deleted table that corresponds to the master table */
        String deletedTable;

        /** The key in the local table the row in table. It may be _id, if table
         * is the local table. */
        String foreignKey;
    }

    /**
     * Used to allow returning sub-classes of {@link Cursor} when calling query.
     */
    public interface CursorFactory {
        /**
         * See
         * {@link SQLiteCursor#SQLiteCursor(SQLiteDatabase, SQLiteCursorDriver,
         * String, SQLiteQuery)}.
         */
        public Cursor newCursor(SQLiteDatabase db,
                SQLiteCursorDriver masterQuery, String editTable,
                SQLiteQuery query);
    }

    /**
     * Open the database according to the flags {@link #OPEN_READWRITE}
     * {@link #OPEN_READONLY} {@link #CREATE_IF_NECESSARY} and/or {@link #NO_LOCALIZED_COLLATORS}.
     *
     * <p>Sets the locale of the database to the  the system's current locale.
     * Call {@link #setLocale} if you would like something else.</p>
     *
     * @param path to database file to open and/or create
     * @param factory an optional factory class that is called to instantiate a
     *            cursor when query is called, or null for default
     * @param flags to control database access mode
     * @return the newly opened database
     * @throws SQLiteException if the database cannot be opened
     */
    public static SQLiteDatabase openDatabase(String path, CursorFactory factory, int flags) {
        SQLiteDatabase sqliteDatabase = null;
        try {
            // Open the database.
            sqliteDatabase = new SQLiteDatabase(path, factory, flags);
            if (SQLiteDebug.DEBUG_SQL_STATEMENTS) {
                sqliteDatabase.enableSqlTracing(path);
            }
            if (SQLiteDebug.DEBUG_SQL_TIME) {
                sqliteDatabase.enableSqlProfiling(path);
            }
        } catch (SQLiteDatabaseCorruptException e) {
            // Try to recover from this, if we can.
            // TODO: should we do this for other open failures?
            Log.e(TAG, "Deleting and re-creating corrupt database " + path, e);
            EventLog.writeEvent(EVENT_DB_CORRUPT, path);
            if (!path.equalsIgnoreCase(":memory")) {
                // delete is only for non-memory database files
                new File(path).delete();
            }
            sqliteDatabase = new SQLiteDatabase(path, factory, flags);
        }
        ActiveDatabases.getInstance().mActiveDatabases.add(
                new WeakReference<SQLiteDatabase>(sqliteDatabase));
        return sqliteDatabase;
    }

    /**
     * Equivalent to openDatabase(file.getPath(), factory, CREATE_IF_NECESSARY).
     */
    public static SQLiteDatabase openOrCreateDatabase(File file, CursorFactory factory) {
        return openOrCreateDatabase(file.getPath(), factory);
    }

    /**
     * Equivalent to openDatabase(path, factory, CREATE_IF_NECESSARY).
     */
    public static SQLiteDatabase openOrCreateDatabase(String path, CursorFactory factory) {
        return openDatabase(path, factory, CREATE_IF_NECESSARY);
    }

    /**
     * Create a memory backed SQLite database.  Its contents will be destroyed
     * when the database is closed.
     *
     * <p>Sets the locale of the database to the  the system's current locale.
     * Call {@link #setLocale} if you would like something else.</p>
     *
     * @param factory an optional factory class that is called to instantiate a
     *            cursor when query is called
     * @return a SQLiteDatabase object, or null if the database can't be created
     */
    public static SQLiteDatabase create(CursorFactory factory) {
        // This is a magic string with special meaning for SQLite.
        return openDatabase(":memory:", factory, CREATE_IF_NECESSARY);
    }

    /**
     * Close the database.
     */
    public void close() {
        if (!isOpen()) {
            return; // already closed
        }
        lock();
        try {
            closeClosable();
            // close this database instance - regardless of its reference count value
            onAllReferencesReleased();
        } finally {
            unlock();
        }
    }

    private void closeClosable() {
        /* deallocate all compiled sql statement objects from mCompiledQueries cache.
         * this should be done before de-referencing all {@link SQLiteClosable} objects
         * from this database object because calling
         * {@link SQLiteClosable#onAllReferencesReleasedFromContainer()} could cause the database
         * to be closed. sqlite doesn't let a database close if there are
         * any unfinalized statements - such as the compiled-sql objects in mCompiledQueries.
         */
        deallocCachedSqlStatements();

        Iterator<Map.Entry iter = mPrograms.entrySet().iterator();
        while (iter.hasNext()) {
            Map.Entry<SQLiteClosable, Object> entry = iter.next();
            SQLiteClosable program = entry.getKey();
            if (program != null) {
                program.onAllReferencesReleasedFromContainer();
            }
        }
    }

    /**
     * Native call to close the database.
     */
    private native void dbclose();

    /**
     * Gets the database version.
     *
     * @return the database version
     */
    public int getVersion() {
        SQLiteStatement prog = null;
        lock();
        if (!isOpen()) {
            throw new IllegalStateException("database not open");
        }
        try {
            prog = new SQLiteStatement(this, "PRAGMA user_version;");
            long version = prog.simpleQueryForLong();
            return (int) version;
        } finally {
            if (prog != null) prog.close();
            unlock();
        }
    }

    /**
     * Sets the database version.
     *
     * @param version the new database version
     */
    public void setVersion(int version) {
        execSQL("PRAGMA user_version = " + version);
    }

    /**
     * Returns the maximum size the database may grow to.
     *
     * @return the new maximum database size
     */
    public long getMaximumSize() {
        SQLiteStatement prog = null;
        lock();
        if (!isOpen()) {
            throw new IllegalStateException("database not open");
        }
        try {
            prog = new SQLiteStatement(this,
                    "PRAGMA max_page_count;");
            long pageCount = prog.simpleQueryForLong();
            return pageCount * getPageSize();
        } finally {
            if (prog != null) prog.close();
            unlock();
        }
    }

    /**
     * Sets the maximum size the database will grow to. The maximum size cannot
     * be set below the current size.
     *
     * @param numBytes the maximum database size, in bytes
     * @return the new maximum database size
     */
    public long setMaximumSize(long numBytes) {
        SQLiteStatement prog = null;
        lock();
        if (!isOpen()) {
            throw new IllegalStateException("database not open");
        }
        try {
            long pageSize = getPageSize();
            long numPages = numBytes / pageSize;
            // If numBytes isn't a multiple of pageSize, bump up a page
            if ((numBytes % pageSize) != 0) {
                numPages++;
            }
            prog = new SQLiteStatement(this,
                    "PRAGMA max_page_count = " + numPages);
            long newPageCount = prog.simpleQueryForLong();
            return newPageCount * pageSize;
        } finally {
            if (prog != null) prog.close();
            unlock();
        }
    }

    /**
     * Returns the current database page size, in bytes.
     *
     * @return the database page size, in bytes
     */
    public long getPageSize() {
        SQLiteStatement prog = null;
        lock();
        if (!isOpen()) {
            throw new IllegalStateException("database not open");
        }
        try {
            prog = new SQLiteStatement(this,
                    "PRAGMA page_size;");
            long size = prog.simpleQueryForLong();
            return size;
        } finally {
            if (prog != null) prog.close();
            unlock();
        }
    }

    /**
     * Sets the database page size. The page size must be a power of two. This
     * method does not work if any data has been written to the database file,
     * and must be called right after the database has been created.
     *
     * @param numBytes the database page size, in bytes
     */
    public void setPageSize(long numBytes) {
        execSQL("PRAGMA page_size = " + numBytes);
    }

    /**
     * Mark this table as syncable. When an update occurs in this table the
     * _sync_dirty field will be set to ensure proper syncing operation.
     *
     * @param table the table to mark as syncable
     * @param deletedTable The deleted table that corresponds to the
     *          syncable table
     */
    public void markTableSyncable(String table, String deletedTable) {
        markTableSyncable(table, "_id", table, deletedTable);
    }

    /**
     * Mark this table as syncable, with the _sync_dirty residing in another
     * table. When an update occurs in this table the _sync_dirty field of the
     * row in updateTable with the _id in foreignKey will be set to
     * ensure proper syncing operation.
     *
     * @param table an update on this table will trigger a sync time removal
     * @param foreignKey this is the column in table whose value is an _id in
     *          updateTable
     * @param updateTable this is the table that will have its _sync_dirty
     */
    public void markTableSyncable(String table, String foreignKey,
            String updateTable) {
        markTableSyncable(table, foreignKey, updateTable, null);
    }

    /**
     * Mark this table as syncable, with the _sync_dirty residing in another
     * table. When an update occurs in this table the _sync_dirty field of the
     * row in updateTable with the _id in foreignKey will be set to
     * ensure proper syncing operation.
     *
     * @param table an update on this table will trigger a sync time removal
     * @param foreignKey this is the column in table whose value is an _id in
     *          updateTable
     * @param updateTable this is the table that will have its _sync_dirty
     * @param deletedTable The deleted table that corresponds to the
     *          updateTable
     */
    private void markTableSyncable(String table, String foreignKey,
            String updateTable, String deletedTable) {
        lock();
        try {
            native_execSQL("SELECT _sync_dirty FROM " + updateTable
                    + " LIMIT 0");
            native_execSQL("SELECT " + foreignKey + " FROM " + table
                    + " LIMIT 0");
        } finally {
            unlock();
        }

        SyncUpdateInfo info = new SyncUpdateInfo(updateTable, deletedTable,
                foreignKey);
        synchronized (mSyncUpdateInfo) {
            mSyncUpdateInfo.put(table, info);
        }
    }

    /**
     * Call for each row that is updated in a cursor.
     *
     * @param table the table the row is in
     * @param rowId the row ID of the updated row
     */
    /* package */ void rowUpdated(String table, long rowId) {
        SyncUpdateInfo info;
        synchronized (mSyncUpdateInfo) {
            info = mSyncUpdateInfo.get(table);
        }
        if (info != null) {
            execSQL("UPDATE " + info.masterTable
                    + " SET _sync_dirty=1 WHERE _id=(SELECT " + info.foreignKey
                    + " FROM " + table + " WHERE _id=" + rowId + ")");
        }
    }

    /**
     * Finds the name of the first table, which is editable.
     *
     * @param tables a list of tables
     * @return the first table listed
     */
    public static String findEditTable(String tables) {
        if (!TextUtils.isEmpty(tables)) {
            // find the first word terminated by either a space or a comma
            int spacepos = tables.indexOf(' ');
            int commapos = tables.indexOf(',');

            if (spacepos > 0 && (spacepos < commapos || commapos < 0)) {
                return tables.substring(0, spacepos);
            } else if (commapos > 0 && (commapos < spacepos || spacepos < 0) ) {
                return tables.substring(0, commapos);
            }
            return tables;
        } else {
            throw new IllegalStateException("Invalid tables");
        }
    }

    /**
     * Compiles an SQL statement into a reusable pre-compiled statement object.
     * The parameters are identical to {@link #execSQL(String)}. You may put ?s in the
     * statement and fill in those values with {@link SQLiteProgram#bindString}
     * and {@link SQLiteProgram#bindLong} each time you want to run the
     * statement. Statements may not return result sets larger than 1x1.
     *
     * @param sql The raw SQL statement, may contain ? for unknown values to be
     *            bound later.
     * @return A pre-compiled {@link SQLiteStatement} object. Note that
     * {@link SQLiteStatement}s are not synchronized, see the documentation for more details.
     */
    public SQLiteStatement compileStatement(String sql) throws SQLException {
        lock();
        if (!isOpen()) {
            throw new IllegalStateException("database not open");
        }
        try {
            return new SQLiteStatement(this, sql);
        } finally {
            unlock();
        }
    }

    /**
     * Query the given URL, returning a {@link Cursor} over the result set.
     *
     * @param distinct true if you want each row to be unique, false otherwise.
     * @param table The table name to compile the query against.
     * @param columns A list of which columns to return. Passing null will
     *            return all columns, which is discouraged to prevent reading
     *            data from storage that isn't going to be used.
     * @param selection A filter declaring which rows to return, formatted as an
     *            SQL WHERE clause (excluding the WHERE itself). Passing null
     *            will return all rows for the given table.
     * @param selectionArgs You may include ?s in selection, which will be
     *         replaced by the values from selectionArgs, in order that they
     *         appear in the selection. The values will be bound as Strings.
     * @param groupBy A filter declaring how to group rows, formatted as an SQL
     *            GROUP BY clause (excluding the GROUP BY itself). Passing null
     *            will cause the rows to not be grouped.
     * @param having A filter declare which row groups to include in the cursor,
     *            if row grouping is being used, formatted as an SQL HAVING
     *            clause (excluding the HAVING itself). Passing null will cause
     *            all row groups to be included, and is required when row
     *            grouping is not being used.
     * @param orderBy How to order the rows, formatted as an SQL ORDER BY clause
     *            (excluding the ORDER BY itself). Passing null will use the
     *            default sort order, which may be unordered.
     * @param limit Limits the number of rows returned by the query,
     *            formatted as LIMIT clause. Passing null denotes no LIMIT clause.
     * @return A {@link Cursor} object, which is positioned before the first entry. Note that
     * {@link Cursor}s are not synchronized, see the documentation for more details.
     * @see Cursor
     */
    public Cursor query(boolean distinct, String table, String[] columns,
            String selection, String[] selectionArgs, String groupBy,
            String having, String orderBy, String limit) {
        return queryWithFactory(null, distinct, table, columns, selection, selectionArgs,
                groupBy, having, orderBy, limit);
    }

    /**
     * Query the given URL, returning a {@link Cursor} over the result set.
     *
     * @param cursorFactory the cursor factory to use, or null for the default factory
     * @param distinct true if you want each row to be unique, false otherwise.
     * @param table The table name to compile the query against.
     * @param columns A list of which columns to return. Passing null will
     *            return all columns, which is discouraged to prevent reading
     *            data from storage that isn't going to be used.
     * @param selection A filter declaring which rows to return, formatted as an
     *            SQL WHERE clause (excluding the WHERE itself). Passing null
     *            will return all rows for the given table.
     * @param selectionArgs You may include ?s in selection, which will be
     *         replaced by the values from selectionArgs, in order that they
     *         appear in the selection. The values will be bound as Strings.
     * @param groupBy A filter declaring how to group rows, formatted as an SQL
     *            GROUP BY clause (excluding the GROUP BY itself). Passing null
     *            will cause the rows to not be grouped.
     * @param having A filter declare which row groups to include in the cursor,
     *            if row grouping is being used, formatted as an SQL HAVING
     *            clause (excluding the HAVING itself). Passing null will cause
     *            all row groups to be included, and is required when row
     *            grouping is not being used.
     * @param orderBy How to order the rows, formatted as an SQL ORDER BY clause
     *            (excluding the ORDER BY itself). Passing null will use the
     *            default sort order, which may be unordered.
     * @param limit Limits the number of rows returned by the query,
     *            formatted as LIMIT clause. Passing null denotes no LIMIT clause.
     * @return A {@link Cursor} object, which is positioned before the first entry. Note that
     * {@link Cursor}s are not synchronized, see the documentation for more details.
     * @see Cursor
     */
    public Cursor queryWithFactory(CursorFactory cursorFactory,
            boolean distinct, String table, String[] columns,
            String selection, String[] selectionArgs, String groupBy,
            String having, String orderBy, String limit) {
        if (!isOpen()) {
            throw new IllegalStateException("database not open");
        }
        String sql = SQLiteQueryBuilder.buildQueryString(
                distinct, table, columns, selection, groupBy, having, orderBy, limit);

        return rawQueryWithFactory(
                cursorFactory, sql, selectionArgs, findEditTable(table));
    }

    /**
     * Query the given table, returning a {@link Cursor} over the result set.
     *
     * @param table The table name to compile the query against.
     * @param columns A list of which columns to return. Passing null will
     *            return all columns, which is discouraged to prevent reading
     *            data from storage that isn't going to be used.
     * @param selection A filter declaring which rows to return, formatted as an
     *            SQL WHERE clause (excluding the WHERE itself). Passing null
     *            will return all rows for the given table.
     * @param selectionArgs You may include ?s in selection, which will be
     *         replaced by the values from selectionArgs, in order that they
     *         appear in the selection. The values will be bound as Strings.
     * @param groupBy A filter declaring how to group rows, formatted as an SQL
     *            GROUP BY clause (excluding the GROUP BY itself). Passing null
     *            will cause the rows to not be grouped.
     * @param having A filter declare which row groups to include in the cursor,
     *            if row grouping is being used, formatted as an SQL HAVING
     *            clause (excluding the HAVING itself). Passing null will cause
     *            all row groups to be included, and is required when row
     *            grouping is not being used.
     * @param orderBy How to order the rows, formatted as an SQL ORDER BY clause
     *            (excluding the ORDER BY itself). Passing null will use the
     *            default sort order, which may be unordered.
     * @return A {@link Cursor} object, which is positioned before the first entry. Note that
     * {@link Cursor}s are not synchronized, see the documentation for more details.
     * @see Cursor
     */
    public Cursor query(String table, String[] columns, String selection,
            String[] selectionArgs, String groupBy, String having,
            String orderBy) {

        return query(false, table, columns, selection, selectionArgs, groupBy,
                having, orderBy, null /* limit */);
    }

    /**
     * Query the given table, returning a {@link Cursor} over the result set.
     *
     * @param table The table name to compile the query against.
     * @param columns A list of which columns to return. Passing null will
     *            return all columns, which is discouraged to prevent reading
     *            data from storage that isn't going to be used.
     * @param selection A filter declaring which rows to return, formatted as an
     *            SQL WHERE clause (excluding the WHERE itself). Passing null
     *            will return all rows for the given table.
     * @param selectionArgs You may include ?s in selection, which will be
     *         replaced by the values from selectionArgs, in order that they
     *         appear in the selection. The values will be bound as Strings.
     * @param groupBy A filter declaring how to group rows, formatted as an SQL
     *            GROUP BY clause (excluding the GROUP BY itself). Passing null
     *            will cause the rows to not be grouped.
     * @param having A filter declare which row groups to include in the cursor,
     *            if row grouping is being used, formatted as an SQL HAVING
     *            clause (excluding the HAVING itself). Passing null will cause
     *            all row groups to be included, and is required when row
     *            grouping is not being used.
     * @param orderBy How to order the rows, formatted as an SQL ORDER BY clause
     *            (excluding the ORDER BY itself). Passing null will use the
     *            default sort order, which may be unordered.
     * @param limit Limits the number of rows returned by the query,
     *            formatted as LIMIT clause. Passing null denotes no LIMIT clause.
     * @return A {@link Cursor} object, which is positioned before the first entry. Note that
     * {@link Cursor}s are not synchronized, see the documentation for more details.
     * @see Cursor
     */
    public Cursor query(String table, String[] columns, String selection,
            String[] selectionArgs, String groupBy, String having,
            String orderBy, String limit) {

        return query(false, table, columns, selection, selectionArgs, groupBy,
                having, orderBy, limit);
    }

    /**
     * Runs the provided SQL and returns a {@link Cursor} over the result set.
     *
     * @param sql the SQL query. The SQL string must not be ; terminated
     * @param selectionArgs You may include ?s in where clause in the query,
     *     which will be replaced by the values from selectionArgs. The
     *     values will be bound as Strings.
     * @return A {@link Cursor} object, which is positioned before the first entry. Note that
     * {@link Cursor}s are not synchronized, see the documentation for more details.
     */
    public Cursor rawQuery(String sql, String[] selectionArgs) {
        return rawQueryWithFactory(null, sql, selectionArgs, null);
    }

    /**
     * Runs the provided SQL and returns a cursor over the result set.
     *
     * @param cursorFactory the cursor factory to use, or null for the default factory
     * @param sql the SQL query. The SQL string must not be ; terminated
     * @param selectionArgs You may include ?s in where clause in the query,
     *     which will be replaced by the values from selectionArgs. The
     *     values will be bound as Strings.
     * @param editTable the name of the first table, which is editable
     * @return A {@link Cursor} object, which is positioned before the first entry. Note that
     * {@link Cursor}s are not synchronized, see the documentation for more details.
     */
    public Cursor rawQueryWithFactory(
            CursorFactory cursorFactory, String sql, String[] selectionArgs,
            String editTable) {
        if (!isOpen()) {
            throw new IllegalStateException("database not open");
        }
        long timeStart = 0;

        if (Config.LOGV || mSlowQueryThreshold != -1) {
            timeStart = System.currentTimeMillis();
        }

        SQLiteCursorDriver driver = new SQLiteDirectCursorDriver(this, sql, editTable);

        Cursor cursor = null;
        try {
            cursor = driver.query(
                    cursorFactory != null ? cursorFactory : mFactory,
                    selectionArgs);
        } finally {
            if (Config.LOGV || mSlowQueryThreshold != -1) {

                // Force query execution
                int count = -1;
                if (cursor != null) {
                    count = cursor.getCount();
                }

                long duration = System.currentTimeMillis() - timeStart;

                if (Config.LOGV || duration >= mSlowQueryThreshold) {
                    Log.v(SQLiteCursor.TAG,
                          "query (" + duration + " ms): " + driver.toString() + ", args are "
                                  + (selectionArgs != null
                                  ? TextUtils.join(",", selectionArgs)
                                  : "<null>")  + ", count is " + count);
                }
            }
        }
        return cursor;
    }

    /**
     * Runs the provided SQL and returns a cursor over the result set.
     * The cursor will read an initial set of rows and the return to the caller.
     * It will continue to read in batches and send data changed notifications
     * when the later batches are ready.
     * @param sql the SQL query. The SQL string must not be ; terminated
     * @param selectionArgs You may include ?s in where clause in the query,
     *     which will be replaced by the values from selectionArgs. The
     *     values will be bound as Strings.
     * @param initialRead set the initial count of items to read from the cursor
     * @param maxRead set the count of items to read on each iteration after the first
     * @return A {@link Cursor} object, which is positioned before the first entry. Note that
     * {@link Cursor}s are not synchronized, see the documentation for more details.
     *
     * This work is incomplete and not fully tested or reviewed, so currently
     * hidden.
     * @hide
     */
    public Cursor rawQuery(String sql, String[] selectionArgs,
            int initialRead, int maxRead) {
        SQLiteCursor c = (SQLiteCursor)rawQueryWithFactory(
                null, sql, selectionArgs, null);
        c.setLoadStyle(initialRead, maxRead);
        return c;
    }

    /**
     * Convenience method for inserting a row into the database.
     *
     * @param table the table to insert the row into
     * @param nullColumnHack SQL doesn't allow inserting a completely empty row,
     *            so if initialValues is empty this column will explicitly be
     *            assigned a NULL value
     * @param values this map contains the initial column values for the
     *            row. The keys should be the column names and the values the
     *            column values
     * @return the row ID of the newly inserted row, or -1 if an error occurred
     */
    public long insert(String table, String nullColumnHack, ContentValues values) {
        try {
            return insertWithOnConflict(table, nullColumnHack, values, CONFLICT_NONE);
        } catch (SQLException e) {
            Log.e(TAG, "Error inserting " + values, e);
            return -1;
        }
    }

    /**
     * Convenience method for inserting a row into the database.
     *
     * @param table the table to insert the row into
     * @param nullColumnHack SQL doesn't allow inserting a completely empty row,
     *            so if initialValues is empty this column will explicitly be
     *            assigned a NULL value
     * @param values this map contains the initial column values for the
     *            row. The keys should be the column names and the values the
     *            column values
     * @throws SQLException
     * @return the row ID of the newly inserted row, or -1 if an error occurred
     */
    public long insertOrThrow(String table, String nullColumnHack, ContentValues values)
            throws SQLException {
        return insertWithOnConflict(table, nullColumnHack, values, CONFLICT_NONE);
    }

    /**
     * Convenience method for replacing a row in the database.
     *
     * @param table the table in which to replace the row
     * @param nullColumnHack SQL doesn't allow inserting a completely empty row,
     *            so if initialValues is empty this row will explicitly be
     *            assigned a NULL value
     * @param initialValues this map contains the initial column values for
     *   the row. The key
     * @return the row ID of the newly inserted row, or -1 if an error occurred
     */
    public long replace(String table, String nullColumnHack, ContentValues initialValues) {
        try {
            return insertWithOnConflict(table, nullColumnHack, initialValues,
                    CONFLICT_REPLACE);
        } catch (SQLException e) {
            Log.e(TAG, "Error inserting " + initialValues, e);
            return -1;
        }
    }

    /**
     * Convenience method for replacing a row in the database.
     *
     * @param table the table in which to replace the row
     * @param nullColumnHack SQL doesn't allow inserting a completely empty row,
     *            so if initialValues is empty this row will explicitly be
     *            assigned a NULL value
     * @param initialValues this map contains the initial column values for
     *   the row. The key
     * @throws SQLException
     * @return the row ID of the newly inserted row, or -1 if an error occurred
     */
    public long replaceOrThrow(String table, String nullColumnHack,
            ContentValues initialValues) throws SQLException {
        return insertWithOnConflict(table, nullColumnHack, initialValues,
                CONFLICT_REPLACE);
    }

    /**
     * General method for inserting a row into the database.
     *
     * @param table the table to insert the row into
     * @param nullColumnHack SQL doesn't allow inserting a completely empty row,
     *            so if initialValues is empty this column will explicitly be
     *            assigned a NULL value
     * @param initialValues this map contains the initial column values for the
     *            row. The keys should be the column names and the values the
     *            column values
     * @param conflictAlgorithm for insert conflict resolver
     * @return the row ID of the newly inserted row
     * OR the primary key of the existing row if the input param 'conflictAlgorithm' =
     * {@link #CONFLICT_IGNORE}
     * OR -1 if any error
     */
    public long insertWithOnConflict(String table, String nullColumnHack,
            ContentValues initialValues, int conflictAlgorithm) {
        if (!isOpen()) {
            throw new IllegalStateException("database not open");
        }

        // Measurements show most sql lengths <= 152
        StringBuilder sql = new StringBuilder(152);
        sql.append("INSERT");
        sql.append(CONFLICT_VALUES[conflictAlgorithm]);
        sql.append(" INTO ");
        sql.append(table);
        // Measurements show most values lengths < 40
        StringBuilder values = new StringBuilder(40);

        Set<Map.Entry entrySet = null;
        if (initialValues != null && initialValues.size() > 0) {
            entrySet = initialValues.valueSet();
            Iterator<Map.Entry entriesIter = entrySet.iterator();
            sql.append('(');

            boolean needSeparator = false;
            while (entriesIter.hasNext()) {
                if (needSeparator) {
                    sql.append(", ");
                    values.append(", ");
                }
                needSeparator = true;
                Map.Entry<String, Object> entry = entriesIter.next();
                sql.append(entry.getKey());
                values.append('?');
            }

            sql.append(')');
        } else {
            sql.append("(" + nullColumnHack + ") ");
            values.append("NULL");
        }

        sql.append(" VALUES(");
        sql.append(values);
        sql.append(");");

        lock();
        SQLiteStatement statement = null;
        try {
            statement = compileStatement(sql.toString());

            // Bind the values
            if (entrySet != null) {
                int size = entrySet.size();
                Iterator<Map.Entry entriesIter = entrySet.iterator();
                for (int i = 0; i < size; i++) {
                    Map.Entry<String, Object> entry = entriesIter.next();
                    DatabaseUtils.bindObjectToProgram(statement, i + 1, entry.getValue());
                }
            }

            // Run the program and then cleanup
            statement.execute();

            long insertedRowId = lastInsertRow();
            if (insertedRowId == -1) {
                Log.e(TAG, "Error inserting " + initialValues + " using " + sql);
            } else {
                if (Config.LOGD && Log.isLoggable(TAG, Log.VERBOSE)) {
                    Log.v(TAG, "Inserting row " + insertedRowId + " from "
                            + initialValues + " using " + sql);
                }
            }
            return insertedRowId;
        } catch (SQLiteDatabaseCorruptException e) {
            onCorruption();
            throw e;
        } finally {
            if (statement != null) {
                statement.close();
            }
            unlock();
        }
    }

    /**
     * Convenience method for deleting rows in the database.
     *
     * @param table the table to delete from
     * @param whereClause the optional WHERE clause to apply when deleting.
     *            Passing null will delete all rows.
     * @return the number of rows affected if a whereClause is passed in, 0
     *         otherwise. To remove all rows and get a count pass "1" as the
     *         whereClause.
     */
    public int delete(String table, String whereClause, String[] whereArgs) {
        lock();
        if (!isOpen()) {
            throw new IllegalStateException("database not open");
        }
        SQLiteStatement statement = null;
        try {
            statement = compileStatement("DELETE FROM " + table
                    + (!TextUtils.isEmpty(whereClause)
                    ? " WHERE " + whereClause : ""));
            if (whereArgs != null) {
                int numArgs = whereArgs.length;
                for (int i = 0; i < numArgs; i++) {
                    DatabaseUtils.bindObjectToProgram(statement, i + 1, whereArgs[i]);
                }
            }
            statement.execute();
            return lastChangeCount();
        } catch (SQLiteDatabaseCorruptException e) {
            onCorruption();
            throw e;
        } finally {
            if (statement != null) {
                statement.close();
            }
            unlock();
        }
    }

    /**
     * Convenience method for updating rows in the database.
     *
     * @param table the table to update in
     * @param values a map from column names to new column values. null is a
     *            valid value that will be translated to NULL.
     * @param whereClause the optional WHERE clause to apply when updating.
     *            Passing null will update all rows.
     * @return the number of rows affected
     */
    public int update(String table, ContentValues values, String whereClause, String[] whereArgs) {
        return updateWithOnConflict(table, values, whereClause, whereArgs, CONFLICT_NONE);
    }

    /**
     * Convenience method for updating rows in the database.
     *
     * @param table the table to update in
     * @param values a map from column names to new column values. null is a
     *            valid value that will be translated to NULL.
     * @param whereClause the optional WHERE clause to apply when updating.
     *            Passing null will update all rows.
     * @param conflictAlgorithm for update conflict resolver
     * @return the number of rows affected
     */
    public int updateWithOnConflict(String table, ContentValues values,
            String whereClause, String[] whereArgs, int conflictAlgorithm) {
        if (values == null || values.size() == 0) {
            throw new IllegalArgumentException("Empty values");
        }

        StringBuilder sql = new StringBuilder(120);
        sql.append("UPDATE ");
        sql.append(CONFLICT_VALUES[conflictAlgorithm]);
        sql.append(table);
        sql.append(" SET ");

        Set<Map.Entry entrySet = values.valueSet();
        Iterator<Map.Entry entriesIter = entrySet.iterator();

        while (entriesIter.hasNext()) {
            Map.Entry<String, Object> entry = entriesIter.next();
            sql.append(entry.getKey());
            sql.append("=?");
            if (entriesIter.hasNext()) {
                sql.append(", ");
            }
        }

        if (!TextUtils.isEmpty(whereClause)) {
            sql.append(" WHERE ");
            sql.append(whereClause);
        }

        lock();
        if (!isOpen()) {
            throw new IllegalStateException("database not open");
        }
        SQLiteStatement statement = null;
        try {
            statement = compileStatement(sql.toString());

            // Bind the values
            int size = entrySet.size();
            entriesIter = entrySet.iterator();
            int bindArg = 1;
            for (int i = 0; i < size; i++) {
                Map.Entry<String, Object> entry = entriesIter.next();
                DatabaseUtils.bindObjectToProgram(statement, bindArg, entry.getValue());
                bindArg++;
            }

            if (whereArgs != null) {
                size = whereArgs.length;
                for (int i = 0; i < size; i++) {
                    statement.bindString(bindArg, whereArgs[i]);
                    bindArg++;
                }
            }

            // Run the program and then cleanup
            statement.execute();
            int numChangedRows = lastChangeCount();
            if (Config.LOGD && Log.isLoggable(TAG, Log.VERBOSE)) {
                Log.v(TAG, "Updated " + numChangedRows + " using " + values + " and " + sql);
            }
            return numChangedRows;
        } catch (SQLiteDatabaseCorruptException e) {
            onCorruption();
            throw e;
        } catch (SQLException e) {
            Log.e(TAG, "Error updating " + values + " using " + sql);
            throw e;
        } finally {
            if (statement != null) {
                statement.close();
            }
            unlock();
        }
    }

    /**
     * Execute a single SQL statement that is not a query. For example, CREATE
     * TABLE, DELETE, INSERT, etc. Multiple statements separated by ;s are not
     * supported. it takes a write lock
     *
     * @throws SQLException If the SQL string is invalid for some reason
     */
    public void execSQL(String sql) throws SQLException {
        long timeStart = SystemClock.uptimeMillis();
        lock();
        if (!isOpen()) {
            throw new IllegalStateException("database not open");
        }
        logTimeStat(mLastSqlStatement, timeStart, GET_LOCK_LOG_PREFIX);
        try {
            native_execSQL(sql);
        } catch (SQLiteDatabaseCorruptException e) {
            onCorruption();
            throw e;
        } finally {
            unlock();
        }

        // Log commit statements along with the most recently executed
        // SQL statement for disambiguation.  Note that instance
        // equality to COMMIT_SQL is safe here.
        if (sql == COMMIT_SQL) {
            logTimeStat(mLastSqlStatement, timeStart, COMMIT_SQL);
        } else {
            logTimeStat(sql, timeStart, null);
        }
    }

    /**
     * Execute a single SQL statement that is not a query. For example, CREATE
     * TABLE, DELETE, INSERT, etc. Multiple statements separated by ;s are not
     * supported. it takes a write lock,
     *
     * @param sql
     * @param bindArgs only byte[], String, Long and Double are supported in bindArgs.
     * @throws SQLException If the SQL string is invalid for some reason
     */
    public void execSQL(String sql, Object[] bindArgs) throws SQLException {
        if (bindArgs == null) {
            throw new IllegalArgumentException("Empty bindArgs");
        }
        long timeStart = SystemClock.uptimeMillis();
        lock();
        if (!isOpen()) {
            throw new IllegalStateException("database not open");
        }
        SQLiteStatement statement = null;
        try {
            statement = compileStatement(sql);
            if (bindArgs != null) {
                int numArgs = bindArgs.length;
                for (int i = 0; i < numArgs; i++) {
                    DatabaseUtils.bindObjectToProgram(statement, i + 1, bindArgs[i]);
                }
            }
            statement.execute();
        } catch (SQLiteDatabaseCorruptException e) {
            onCorruption();
            throw e;
        } finally {
            if (statement != null) {
                statement.close();
            }
            unlock();
        }
        logTimeStat(sql, timeStart);
    }

    @Override
    protected void finalize() {
        if (isOpen()) {
            Log.e(TAG, "close() was never explicitly called on database '" +
                    mPath + "' ", mStackTrace);
            closeClosable();
            onAllReferencesReleased();
        }
    }

    /**
     * Private constructor. See {@link #create} and {@link #openDatabase}.
     *
     * @param path The full path to the database
     * @param factory The factory to use when creating cursors, may be NULL.
     * @param flags 0 or {@link #NO_LOCALIZED_COLLATORS}.  If the database file already
     *              exists, mFlags will be updated appropriately.
     */
    private SQLiteDatabase(String path, CursorFactory factory, int flags) {
        if (path == null) {
            throw new IllegalArgumentException("path should not be null");
        }
        mFlags = flags;
        mPath = path;
        mSlowQueryThreshold = SystemProperties.getInt(LOG_SLOW_QUERIES_PROPERTY, -1);
        mStackTrace = new DatabaseObjectNotClosedException().fillInStackTrace();
        mFactory = factory;
        dbopen(mPath, mFlags);
        if (SQLiteDebug.DEBUG_SQL_CACHE) {
            mTimeOpened = getTime();
        }
        mPrograms = new WeakHashMap<SQLiteClosable,Object>();
        try {
            setLocale(Locale.getDefault());
        } catch (RuntimeException e) {
            Log.e(TAG, "Failed to setLocale() when constructing, closing the database", e);
            dbclose();
            if (SQLiteDebug.DEBUG_SQL_CACHE) {
                mTimeClosed = getTime();
            }
            throw e;
        }
    }

    private String getTime() {
        return new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS ").format(System.currentTimeMillis());
    }

    /**
     * return whether the DB is opened as read only.
     * @return true if DB is opened as read only
     */
    public boolean isReadOnly() {
        return (mFlags & OPEN_READ_MASK) == OPEN_READONLY;
    }

    /**
     * @return true if the DB is currently open (has not been closed)
     */
    public boolean isOpen() {
        return mNativeHandle != 0;
    }

    public boolean needUpgrade(int newVersion) {
        return newVersion > getVersion();
    }

    /**
     * Getter for the path to the database file.
     *
     * @return the path to our database file.
     */
    public final String getPath() {
        return mPath;
    }

    /* package */ void logTimeStat(String sql, long beginMillis) {
        logTimeStat(sql, beginMillis, null);
    }

    /* package */ void logTimeStat(String sql, long beginMillis, String prefix) {
        // Keep track of the last statement executed here, as this is
        // the common funnel through which all methods of hitting
        // libsqlite eventually flow.
        mLastSqlStatement = sql;

        // Sample fast queries in proportion to the time taken.
        // Quantize the % first, so the logged sampling probability
        // exactly equals the actual sampling rate for this query.

        int samplePercent;
        long durationMillis = SystemClock.uptimeMillis() - beginMillis;
        if (durationMillis == 0 && prefix == GET_LOCK_LOG_PREFIX) {
            // The common case is locks being uncontended.  Don't log those,
            // even at 1%, which is our default below.
            return;
        }
        if (sQueryLogTimeInMillis == 0) {
            sQueryLogTimeInMillis = SystemProperties.getInt("db.db_operation.threshold_ms", 500);
        }
        if (durationMillis >= sQueryLogTimeInMillis) {
            samplePercent = 100;
        } else {;
            samplePercent = (int) (100 * durationMillis / sQueryLogTimeInMillis) + 1;
            if (mRandom.nextInt(100) >= samplePercent) return;
        }

        // Note: the prefix will be "COMMIT;" or "GETLOCK:" when non-null.  We wait to do
        // it here so we avoid allocating in the common case.
        if (prefix != null) {
            sql = prefix + sql;
        }

        if (sql.length() > QUERY_LOG_SQL_LENGTH) sql = sql.substring(0, QUERY_LOG_SQL_LENGTH);

        // ActivityThread.currentPackageName() only returns non-null if the
        // current thread is an application main thread.  This parameter tells
        // us whether an event loop is blocked, and if so, which app it is.
        //
        // Sadly, there's no fast way to determine app name if this is *not* a
        // main thread, or when we are invoked via Binder (e.g. ContentProvider).
        // Hopefully the full path to the database will be informative enough.

        String blockingPackage = ActivityThread.currentPackageName();
        if (blockingPackage == null) blockingPackage = "";

        EventLog.writeEvent(
            EVENT_DB_OPERATION,
            getPathForLogs(),
            sql,
            durationMillis,
            blockingPackage,
            samplePercent);
    }

    /**
     * Removes email addresses from database filenames before they're
     * logged to the EventLog where otherwise apps could potentially
     * read them.
     */
    private String getPathForLogs() {
        if (mPathForLogs != null) {
            return mPathForLogs;
        }
        if (mPath == null) {
            return null;
        }
        if (mPath.indexOf('@') == -1) {
            mPathForLogs = mPath;
        } else {
            mPathForLogs = EMAIL_IN_DB_PATTERN.matcher(mPath).replaceAll("XX@YY");
        }
        return mPathForLogs;
    }

    /**
     * Sets the locale for this database.  Does nothing if this database has
     * the NO_LOCALIZED_COLLATORS flag set or was opened read only.
     * @throws SQLException if the locale could not be set.  The most common reason
     * for this is that there is no collator available for the locale you requested.
     * In this case the database remains unchanged.
     */
    public void setLocale(Locale locale) {
        lock();
        try {
            native_setLocale(locale.toString(), mFlags);
        } finally {
            unlock();
        }
    }

    /*
     * ============================================================================
     *
     *       The following methods deal with compiled-sql cache
     * ============================================================================
     */
    /**
     * adds the given sql and its compiled-statement-id-returned-by-sqlite to the
     * cache of compiledQueries attached to 'this'.
     *
     * if there is already a {@link SQLiteCompiledSql} in compiledQueries for the given sql,
     * the new {@link SQLiteCompiledSql} object is NOT inserted into the cache (i.e.,the current
     * mapping is NOT replaced with the new mapping).
     */
    /* package */ void addToCompiledQueries(String sql, SQLiteCompiledSql compiledStatement) {
        if (mMaxSqlCacheSize == 0) {
            // for this database, there is no cache of compiled sql.
            if (SQLiteDebug.DEBUG_SQL_CACHE) {
                Log.v(TAG, "|NOT adding_sql_to_cache|" + getPath() + "|" + sql);
            }
            return;
        }

        SQLiteCompiledSql compiledSql = null;
        synchronized(mCompiledQueries) {
            // don't insert the new mapping if a mapping already exists
            compiledSql = mCompiledQueries.get(sql);
            if (compiledSql != null) {
                return;
            }
            // add this <sql, compiledStatement> to the cache
            if (mCompiledQueries.size() == mMaxSqlCacheSize) {
                /*
                 * cache size of {@link #mMaxSqlCacheSize} is not enough for this app.
                 * log a warning MAX_WARNINGS_ON_CACHESIZE_CONDITION times
                 * chances are it is NOT using ? for bindargs - so caching is useless.
                 * TODO: either let the callers set max cchesize for their app, or intelligently
                 * figure out what should be cached for a given app.
                 */
                if (++mCacheFullWarnings == MAX_WARNINGS_ON_CACHESIZE_CONDITION) {
                    Log.w(TAG, "Reached MAX size for compiled-sql statement cache for database " +
                            getPath() + "; i.e., NO space for this sql statement in cache: " +
                            sql + ". Please change your sql statements to use '?' for " +
                            "bindargs, instead of using actual values");
                }
                // don't add this entry to cache
            } else {
                // cache is NOT full. add this to cache.
                mCompiledQueries.put(sql, compiledStatement);
                if (SQLiteDebug.DEBUG_SQL_CACHE) {
                    Log.v(TAG, "|adding_sql_to_cache|" + getPath() + "|" +
                            mCompiledQueries.size() + "|" + sql);
                }
            }
        }
        return;
    }


    private void deallocCachedSqlStatements() {
        synchronized (mCompiledQueries) {
            for (SQLiteCompiledSql compiledSql : mCompiledQueries.values()) {
                compiledSql.releaseSqlStatement();
            }
            mCompiledQueries.clear();
        }
    }

    /**
     * from the compiledQueries cache, returns the compiled-statement-id for the given sql.
     * returns null, if not found in the cache.
     */
    /* package */ SQLiteCompiledSql getCompiledStatementForSql(String sql) {
        SQLiteCompiledSql compiledStatement = null;
        boolean cacheHit;
        synchronized(mCompiledQueries) {
            if (mMaxSqlCacheSize == 0) {
                // for this database, there is no cache of compiled sql.
                if (SQLiteDebug.DEBUG_SQL_CACHE) {
                    Log.v(TAG, "|cache NOT found|" + getPath());
                }
                return null;
            }
            cacheHit = (compiledStatement = mCompiledQueries.get(sql)) != null;
        }
        if (cacheHit) {
            mNumCacheHits++;
        } else {
            mNumCacheMisses++;
        }

        if (SQLiteDebug.DEBUG_SQL_CACHE) {
            Log.v(TAG, "|cache_stats|" +
                    getPath() + "|" + mCompiledQueries.size() +
                    "|" + mNumCacheHits + "|" + mNumCacheMisses +
                    "|" + cacheHit + "|" + mTimeOpened + "|" + mTimeClosed + "|" + sql);
        }
        return compiledStatement;
    }

    /**
     * returns true if the given sql is cached in compiled-sql cache.
     * @hide
     */
    public boolean isInCompiledSqlCache(String sql) {
        synchronized(mCompiledQueries) {
            return mCompiledQueries.containsKey(sql);
        }
    }

    /**
     * purges the given sql from the compiled-sql cache.
     * @hide
     */
    public void purgeFromCompiledSqlCache(String sql) {
        synchronized(mCompiledQueries) {
            mCompiledQueries.remove(sql);
        }
    }

    /**
     * remove everything from the compiled sql cache
     * @hide
     */
    public void resetCompiledSqlCache() {
        synchronized(mCompiledQueries) {
            mCompiledQueries.clear();
        }
    }

    /**
     * return the current maxCacheSqlCacheSize
     * @hide
     */
    public synchronized int getMaxSqlCacheSize() {
        return mMaxSqlCacheSize;
    }

    /**
     * set the max size of the compiled sql cache for this database after purging the cache.
     * (size of the cache = number of compiled-sql-statements stored in the cache).
     *
     * max cache size can ONLY be increased from its current size (default = 0).
     * if this method is called with smaller size than the current value of mMaxSqlCacheSize,
     * then IllegalStateException is thrown
     *
     * synchronized because we don't want t threads to change cache size at the same time.
     * @param cacheSize the size of the cache. can be (0 to MAX_SQL_CACHE_SIZE)
     * @throws IllegalStateException if input cacheSize > MAX_SQL_CACHE_SIZE or < 0 or
     * < the value set with previous setMaxSqlCacheSize() call.
     *
     * @hide
     */
    public synchronized void setMaxSqlCacheSize(int cacheSize) {
        if (cacheSize > MAX_SQL_CACHE_SIZE || cacheSize < 0) {
            throw new IllegalStateException("expected value between 0 and " + MAX_SQL_CACHE_SIZE);
        } else if (cacheSize < mMaxSqlCacheSize) {
            throw new IllegalStateException("cannot set cacheSize to a value less than the value " +
                    "set with previous setMaxSqlCacheSize() call.");
        }
        mMaxSqlCacheSize = cacheSize;
    }

    static class ActiveDatabases {
        private static final ActiveDatabases activeDatabases = new ActiveDatabases();
        private HashSet<WeakReference mActiveDatabases =
            new HashSet<WeakReference();
        private ActiveDatabases() {} // disable instantiation of this class
        static ActiveDatabases getInstance() {return activeDatabases;}
    }

    /**
     * this method is used to collect data about ALL open databases in the current process.
     * bugreport is a user of this data. 
     */
    /* package */ static ArrayList<DbStats> getDbStats() {
        ArrayList<DbStats> dbStatsList = new ArrayList();
        for (WeakReference<SQLiteDatabase> w : ActiveDatabases.getInstance().mActiveDatabases) {
            SQLiteDatabase db = w.get();
            if (db == null || !db.isOpen()) {
                continue;
            }
            // get SQLITE_DBSTATUS_LOOKASIDE_USED for the db
            int lookasideUsed = db.native_getDbLookaside();

            // get the lastnode of the dbname
            String path = db.getPath();
            int indx = path.lastIndexOf("/");
            String lastnode = path.substring((indx != -1) ? ++indx : 0);

            // get list of attached dbs and for each db, get its size and pagesize
            ArrayList<Pair attachedDbs = getAttachedDbs(db);
            if (attachedDbs == null) {
                continue;
            }
            for (int i = 0; i < attachedDbs.size(); i++) {
                Pair<String, String> p = attachedDbs.get(i);
                long pageCount = getPragmaVal(db, p.first + ".page_count;");

                // first entry in the attached db list is always the main database
                // don't worry about prefixing the dbname with "main"
                String dbName;
                if (i == 0) {
                    dbName = lastnode;
                } else {
                    // lookaside is only relevant for the main db
                    lookasideUsed = 0;
                    dbName = "  (attached) " + p.first;
                    // if the attached db has a path, attach the lastnode from the path to above
                    if (p.second.trim().length() > 0) {
                        int idx = p.second.lastIndexOf("/");
                        dbName += " : " + p.second.substring((idx != -1) ? ++idx : 0);
                    }
                }
                if (pageCount > 0) {
                    dbStatsList.add(new DbStats(dbName, pageCount, db.getPageSize(),
                            lookasideUsed));
                }
            }
        }
        return dbStatsList;
    }

    /**
     * get the specified pragma value from sqlite for the specified database.
     * only handles pragma's that return int/long.
     * NO JAVA locks are held in this method.
     * TODO: use this to do all pragma's in this class
     */
    private static long getPragmaVal(SQLiteDatabase db, String pragma) {
        if (!db.isOpen()) {
            return 0;
        }
        SQLiteStatement prog = null;
        try {
            prog = new SQLiteStatement(db, "PRAGMA " + pragma);
            long val = prog.simpleQueryForLong();
            return val;
        } finally {
            if (prog != null) prog.close();
        }
    }

    /**
     * returns list of full pathnames of all attached databases
     * including the main database
     * TODO: move this to {@link DatabaseUtils}
     */
    private static ArrayList<Pair getAttachedDbs(SQLiteDatabase dbObj) {
        if (!dbObj.isOpen()) {
            return null;
        }
        ArrayList<Pair attachedDbs = new ArrayList>();
        Cursor c = dbObj.rawQuery("pragma database_list;", null);
        while (c.moveToNext()) {
             attachedDbs.add(new Pair<String, String>(c.getString(1), c.getString(2)));
        }
        c.close();
        return attachedDbs;
    }

    /**
     * Native call to open the database.
     *
     * @param path The full path to the database
     */
    private native void dbopen(String path, int flags);

    /**
     * Native call to setup tracing of all sql statements
     *
     * @param path the full path to the database
     */
    private native void enableSqlTracing(String path);

    /**
     * Native call to setup profiling of all sql statements.
     * currently, sqlite's profiling = printing of execution-time
     * (wall-clock time) of each of the sql statements, as they
     * are executed.
     *
     * @param path the full path to the database
     */
    private native void enableSqlProfiling(String path);

    /**
     * Native call to execute a raw SQL statement. {@link #lock} must be held
     * when calling this method.
     *
     * @param sql The raw SQL string
     * @throws SQLException
     */
    /* package */ native void native_execSQL(String sql) throws SQLException;

    /**
     * Native call to set the locale.  {@link #lock} must be held when calling
     * this method.
     * @throws SQLException
     */
    /* package */ native void native_setLocale(String loc, int flags);

    /**
     * Returns the row ID of the last row inserted into the database.
     *
     * @return the row ID of the last row inserted into the database.
     */
    /* package */ native long lastInsertRow();

    /**
     * Returns the number of changes made in the last statement executed.
     *
     * @return the number of changes made in the last statement executed.
     */
    /* package */ native int lastChangeCount();

    /**
     * return the SQLITE_DBSTATUS_LOOKASIDE_USED documented here
     * http://www.sqlite.org/c3ref/c_dbstatus_lookaside_used.html
     * @return int value of SQLITE_DBSTATUS_LOOKASIDE_USED
     */
    private native int native_getDbLookaside();
}