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Deprecate DatabaseUtils.InsertHelper.

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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
This commit is contained in:
Jeff Brown
2012-06-22 13:37:57 -07:00
parent 880c5f5aea
commit b33eb4e32a
3 changed files with 33 additions and 15 deletions
Download Patch File Download Diff File Expand all files Collapse all files

1
api/16.txt
View File

@@ -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 {

3
api/current.txt
View File

@@ -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 {

44
core/java/android/database/DatabaseUtils.java
View File

@@ -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);