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Commit b33eb4e3 authored by Jeff Brown's avatar Jeff Brown
Browse files

Deprecate DatabaseUtils.InsertHelper. 

This class does not offer any advantages over SQLiteStatement
and just makes code more complex and error-prone.

Documented that the class is not thread-safe.

Removed a potential deadlock in insert() and replace() caused
by the insertInternal() method being synchronized in the case
where the class was being used concurrently (woe to you!).

Thread A would start a transaction.
Thread B would call insertInternal() and acquire the object monitor,
but block because it could not obtain the db connection because
thread A is holding onto it.
Thread A would call insertInternal() and block because Thread B
was holding the object monitor.
Deadlock.

Changed this code to use a transaction instead of a lock,
which provides the necessary mutual exclusion guarantee without
the potential for a deadlock.  Even so, the class really isn't
thread safe.

Bug: 6625094
Change-Id: I51d9a15567a6f2bad6f25e550b48f8f6ffcab2a7
parent 880c5f5a

api/16.txt

+0 −1
Original line number Diff line number Diff line
@@ -7321,7 +7321,6 @@ package android.database { 
    method public void prepareForInsert();

    method public void prepareForReplace();

    method public long replace(android.content.ContentValues);

    field public static final int TABLE_INFO_PRAGMA_DEFAULT_INDEX = 4; // 0x4

  }















  public final class DefaultDatabaseErrorHandler implements android.database.DatabaseErrorHandler {

























api/current.txt



+1
−2




























Original line number
Diff line number
Diff line








@@ -7316,7 +7316,7 @@ package android.database {













    field public static final int STATEMENT_UPDATE = 2; // 0x2















  }



























  public static class DatabaseUtils.InsertHelper {













  public static deprecated class DatabaseUtils.InsertHelper {















    ctor public DatabaseUtils.InsertHelper(android.database.sqlite.SQLiteDatabase, java.lang.String);















    method public void bind(int, double);















    method public void bind(int, float);









@@ -7333,7 +7333,6 @@ package android.database {













    method public void prepareForInsert();















    method public void prepareForReplace();















    method public long replace(android.content.ContentValues);













    field public static final int TABLE_INFO_PRAGMA_DEFAULT_INDEX = 4; // 0x4















  }





























  public final class DefaultDatabaseErrorHandler implements android.database.DatabaseErrorHandler {

























core/java/android/database/DatabaseUtils.java



+32
−12




























Original line number
Diff line number
Diff line








@@ -50,9 +50,6 @@ public class DatabaseUtils {













    private static final String TAG = "DatabaseUtils";































    private static final boolean DEBUG = false;













    private static final boolean LOCAL_LOGV = false;



























    private static final String[] countProjection = new String[]{"count(*)"};































    /** One of the values returned by {@link #getSqlStatementType(String)}. */















    public static final int STATEMENT_SELECT = 1;










@@ -963,10 +960,15 @@ public class DatabaseUtils {













    }































    /**













     * This class allows users to do multiple inserts into a table but













     * compile the SQL insert statement only once, which may increase













     * performance.













     * This class allows users to do multiple inserts into a table using













     * the same statement.













     * <p>













     * This class is not thread-safe.













     * </p>













     *













     * @deprecated Use {@link SQLiteStatement} instead.















     */













    @Deprecated















    public static class InsertHelper {















        private final SQLiteDatabase mDb;















        private final String mTableName;









@@ -983,6 +985,13 @@ public class DatabaseUtils {













         * table_info(...)" command that we depend on.















         */















        public static final int TABLE_INFO_PRAGMA_COLUMNNAME_INDEX = 1;



























        /**













         * This field was accidentally exposed in earlier versions of the platform













         * so we can hide it but we can't remove it.













         *













         * @hide













         */















        public static final int TABLE_INFO_PRAGMA_DEFAULT_INDEX = 4;































        /**










@@ -1036,7 +1045,7 @@ public class DatabaseUtils {













            sb.append(sbv);































            mInsertSQL = sb.toString();













            if (LOCAL_LOGV) Log.v(TAG, "insert statement is " + mInsertSQL);













            if (DEBUG) Log.v(TAG, "insert statement is " + mInsertSQL);















        }































        private SQLiteStatement getStatement(boolean allowReplace) throws SQLException {










@@ -1069,24 +1078,35 @@ public class DatabaseUtils {













         * @return the row ID of the newly inserted row, or -1 if an















         * error occurred















         */













        private synchronized long insertInternal(ContentValues values, boolean allowReplace) {













        private long insertInternal(ContentValues values, boolean allowReplace) {













            // Start a transaction even though we don't really need one.













            // This is to help maintain compatibility with applications that













            // access InsertHelper from multiple threads even though they never should have.













            // The original code used to lock the InsertHelper itself which was prone













            // to deadlocks.  Starting a transaction achieves the same mutual exclusion













            // effect as grabbing a lock but without the potential for deadlocks.













            mDb.beginTransactionNonExclusive();















            try {















                SQLiteStatement stmt = getStatement(allowReplace);















                stmt.clearBindings();













                if (LOCAL_LOGV) Log.v(TAG, "--- inserting in table " + mTableName);













                if (DEBUG) Log.v(TAG, "--- inserting in table " + mTableName);















                for (Map.Entry<String, Object> e: values.valueSet()) {















                    final String key = e.getKey();















                    int i = getColumnIndex(key);















                    DatabaseUtils.bindObjectToProgram(stmt, i, e.getValue());













                    if (LOCAL_LOGV) {













                    if (DEBUG) {















                        Log.v(TAG, "binding " + e.getValue() + " to column " +















                              i + " (" + key + ")");















                    }















                }













                return stmt.executeInsert();













                long result = stmt.executeInsert();













                mDb.setTransactionSuccessful();













                return result;















            } catch (SQLException e) {















                Log.e(TAG, "Error inserting " + values + " into table  " + mTableName, e);















                return -1;













            } finally {













                mDb.endTransaction();















            }















        }


























@@ -1223,7 +1243,7 @@ public class DatabaseUtils {













                        + "execute");















            }















            try {













                if (LOCAL_LOGV) Log.v(TAG, "--- doing insert or replace in table " + mTableName);













                if (DEBUG) Log.v(TAG, "--- doing insert or replace in table " + mTableName);















                return mPreparedStatement.executeInsert();















            } catch (SQLException e) {















                Log.e(TAG, "Error executing InsertHelper with table " + mTableName, e);