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Merged
magnusp merged 1 commit into from
Oct 21, 2026
Merged

fix(jdbc): serialize statement close and execute #89

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18 changes: 4 additions & 14 deletions libsql-jdbc/src/main/java/com/github/magnusp/libsql/jdbc/LibsqlPreparedStatement.java
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Original file line number Diff line number Diff line change
Expand Up @@ -64,9 +64,9 @@ public ResultSet executeQuery() throws SQLException {
if (result.cols() == null || result.cols().isEmpty()) {
throw new SQLException("Query does not return results");
}
this.currentResultSet = new LibsqlResultSet(this, result, sql, false);
this.updateCount = -1;
return currentResultSet;
LibsqlResultSet resultSet = new LibsqlResultSet(this, result, sql, false);
assignResultSet(resultSet, false);
return resultSet;
}

@Override
Expand Down Expand Up @@ -217,17 +217,7 @@ private record Token(String word, int depth) {}

@Override
public boolean execute() throws SQLException {
StmtResult result = executeCurrent();
updateGeneratedKeys(sql, result);
if (result.cols() != null && !result.cols().isEmpty()) {
this.currentResultSet = new LibsqlResultSet(this, result, sql, false);
this.updateCount = -1;
return true;
} else {
this.currentResultSet = null;
this.updateCount = result.affectedRowCount();
return false;
}
return executeResult(sql, executeCurrent());
}

private StmtResult executeCurrent() throws SQLException {
Expand Down
246 changes: 162 additions & 84 deletions libsql-jdbc/src/main/java/com/github/magnusp/libsql/jdbc/LibsqlStatement.java
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Original file line number Diff line number Diff line change
Expand Up @@ -37,12 +37,17 @@
* <li>Matching xerial's execute-after-close behavior, {@link #execute(String)}, {@link
* #executeQuery(String)}, {@link #executeUpdate(String)}, and {@link #getConnection()} keep
* working after {@link #close()}. This deliberately copies a likely xerial bug for drop-in
* compatibility; see the issue #47 contract decision.
* compatibility; see the issue #47 contract decision. A result set produced after close is
* returned closed, so a closed statement never holds an open result set.
* <li>{@link #close()} and the execute methods are safe when called concurrently. State
* transitions share one lock; when close wins a race, the execute closes and discards its
* result set instead of attaching it to the closed statement.
* </ul>
*/
public class LibsqlStatement implements Statement {

protected final LibsqlConnection connection;
private final Object stateLock = new Object();
protected LibsqlResultSet currentResultSet = null;
protected long updateCount = -1;
protected boolean closed = false;
Expand All @@ -56,9 +61,17 @@ public LibsqlStatement(LibsqlConnection connection) {
this.connection = connection;
}

/**
* Test seam. Called after the closed check and before a result set is attached to the
* statement, so a test can force a close to interleave with execute.
*/
protected void beforeResultSetAssignment() throws SQLException {}

protected void checkClosed() throws SQLException {
if (closed) {
throw new SQLException("Statement is closed");
synchronized (stateLock) {
if (closed) {
throw new SQLException("Statement is closed");
}
}
if (connection != null) {
connection.checkClosed();
Expand All @@ -71,10 +84,28 @@ public ResultSet executeQuery(String sql) throws SQLException {
if (result.cols() == null || result.cols().isEmpty()) {
throw new SQLException("Query did not produce a ResultSet: " + sql);
}
this.currentResultSet = new LibsqlResultSet(this, result, sql, false);
this.updateCount = -1;
this.resultSetRequested = true;
return currentResultSet;
LibsqlResultSet resultSet = new LibsqlResultSet(this, result, sql, false);
assignResultSet(resultSet, true);
return resultSet;
}

protected void assignResultSet(LibsqlResultSet resultSet, boolean requested)
throws SQLException {
if (!isClosed()) {
beforeResultSetAssignment();
}
synchronized (stateLock) {
if (closed) {
closeResultSet(resultSet);
currentResultSet = null;
resultSetRequested = false;
updateCount = -1;
return;
}
currentResultSet = resultSet;
updateCount = -1;
resultSetRequested = requested;
}
}

@Override
Expand All @@ -85,18 +116,34 @@ public int executeUpdate(String sql) throws SQLException {

@Override
public boolean execute(String sql) throws SQLException {
StmtResult result = executeSql(sql);
updateGeneratedKeys(sql, result);
if (result.cols() != null && !result.cols().isEmpty()) {
this.currentResultSet = new LibsqlResultSet(this, result, sql, false);
this.updateCount = -1;
this.resultSetRequested = false;
return true;
} else {
this.currentResultSet = null;
this.updateCount = result.affectedRowCount();
this.resultSetRequested = false;
return false;
return executeResult(sql, executeSql(sql));
}

protected boolean executeResult(String sql, StmtResult result) throws SQLException {
boolean hasResultSet = result.cols() != null && !result.cols().isEmpty();
LibsqlResultSet resultSet =
hasResultSet ? new LibsqlResultSet(this, result, sql, false) : null;

if (hasResultSet && !isClosed()) {
beforeResultSetAssignment();
}

synchronized (stateLock) {
if (closed) {
clearGeneratedKeys();
if (resultSet != null) {
closeResultSet(resultSet);
}
currentResultSet = null;
resultSetRequested = false;
updateCount = hasResultSet ? -1 : result.affectedRowCount();
return hasResultSet;
}
updateGeneratedKeys(sql, result);
currentResultSet = resultSet;
updateCount = hasResultSet ? -1 : result.affectedRowCount();
resultSetRequested = false;
return hasResultSet;
}
}

Expand All @@ -106,44 +153,58 @@ private StmtResult executeSql(String sql) throws SQLException {
}

protected void closeCurrentResultSet() throws SQLException {
LibsqlResultSet resultSet = currentResultSet;
currentResultSet = null;
resultSetRequested = false;
if (resultSet != null) {
closeResultSet(resultSet);
synchronized (stateLock) {
LibsqlResultSet resultSet = currentResultSet;
currentResultSet = null;
resultSetRequested = false;
if (resultSet != null) {
closeResultSet(resultSet);
}
}
}

private void closeResultSet(LibsqlResultSet resultSet) throws SQLException {
boolean wasClosed = closed;
boolean wasClosing = closing;
closed = false;
closing = true;
try {
resultSet.close();
} finally {
closed = wasClosed;
closing = wasClosing;
synchronized (stateLock) {
boolean wasClosed = closed;
boolean wasClosing = closing;
closed = false;
closing = true;
try {
resultSet.close();
} finally {
closed = wasClosed;
closing = wasClosing;
}
}
}

protected void updateGeneratedKeys(String sql, StmtResult result) throws SQLException {
clearGeneratedKeys();
if (sql != null && result != null && result.lastInsertRowid() != null && isInsertSql(sql)) {
long rowid = result.lastInsertRowid();
StmtResult keys = new StmtResult(
List.of(new Col("last_insert_rowid()", null)),
List.of(new Row(List.of(Value.of(rowid)))),
0,
rowid);
generatedKeys = new LibsqlResultSet(this, keys);
synchronized (stateLock) {
clearGeneratedKeys();
if (sql != null
&& result != null
&& result.lastInsertRowid() != null
&& isInsertSql(sql)) {
long rowid = result.lastInsertRowid();
StmtResult keys = new StmtResult(
List.of(new Col("last_insert_rowid()", null)),
List.of(new Row(List.of(Value.of(rowid)))),
0,
rowid);
generatedKeys = new LibsqlResultSet(this, keys);
}
}
}

protected void clearGeneratedKeys() throws SQLException {
if (generatedKeys != null) {
generatedKeys.close();
synchronized (stateLock) {
ResultSet keys = generatedKeys;
generatedKeys = null;
if (keys instanceof LibsqlResultSet libsqlKeys) {
closeResultSet(libsqlKeys);
} else if (keys != null) {
keys.close();
}
}
}

Expand Down Expand Up @@ -244,35 +305,43 @@ private ResultSet emptyGeneratedKeys() {

@Override
public ResultSet getResultSet() throws SQLException {
checkClosed();
if (currentResultSet == null) {
return null;
}
if (resultSetRequested) {
throw new SQLException("ResultSet already requested");
synchronized (stateLock) {
checkClosed();
if (currentResultSet == null) {
return null;
}
if (resultSetRequested) {
throw new SQLException("ResultSet already requested");
}
resultSetRequested = true;
return currentResultSet;
}
resultSetRequested = true;
return currentResultSet;
}

@Override
public int getUpdateCount() throws SQLException {
checkClosed();
return (int) updateCount;
synchronized (stateLock) {
checkClosed();
return (int) updateCount;
}
}

@Override
public long getLargeUpdateCount() throws SQLException {
checkClosed();
return updateCount;
synchronized (stateLock) {
checkClosed();
return updateCount;
}
}

@Override
public boolean getMoreResults() throws SQLException {
checkClosed();
closeCurrentResultSet();
updateCount = -1;
return false;
synchronized (stateLock) {
checkClosed();
closeCurrentResultSet();
updateCount = -1;
return false;
}
}

@Override
Expand Down Expand Up @@ -304,28 +373,31 @@ public Connection getConnection() throws SQLException {

@Override
public void close() throws SQLException {
if (closing) {
return;
}
closing = true;
try {
closed = false;
clearGeneratedKeys();
LibsqlResultSet resultSet = currentResultSet;
currentResultSet = null;
resultSetRequested = false;
if (resultSet != null) {
resultSet.close();
synchronized (stateLock) {
if (closing) {
return;
}
closing = true;
try {
LibsqlResultSet resultSet = currentResultSet;
currentResultSet = null;
resultSetRequested = false;
clearGeneratedKeys();
if (resultSet != null) {
closeResultSet(resultSet);
}
} finally {
closed = true;
closing = false;
}
} finally {
closed = true;
closing = false;
}
}

@Override
public boolean isClosed() throws SQLException {
return closed;
synchronized (stateLock) {
return closed;
}
}

@Override public int getMaxFieldSize() throws SQLException { return 0; }
Expand Down Expand Up @@ -359,11 +431,13 @@ public boolean getMoreResults(int current) throws SQLException {
}
@Override
public ResultSet getGeneratedKeys() throws SQLException {
checkClosed();
if (generatedKeys == null) {
generatedKeys = emptyGeneratedKeys();
synchronized (stateLock) {
checkClosed();
if (generatedKeys == null) {
generatedKeys = emptyGeneratedKeys();
}
return generatedKeys;
}
return generatedKeys;
}
@Override public int executeUpdate(String sql, int autoGeneratedKeys) throws SQLException { return executeUpdate(sql); }
@Override public int executeUpdate(String sql, int[] columnIndexes) throws SQLException { return executeUpdate(sql); }
Expand All @@ -376,14 +450,18 @@ public ResultSet getGeneratedKeys() throws SQLException {
@Override public boolean isPoolable() throws SQLException { return false; }
@Override
public void closeOnCompletion() throws SQLException {
checkClosedForCompletion();
closeOnCompletion = true;
synchronized (stateLock) {
checkClosedForCompletion();
closeOnCompletion = true;
}
}

@Override
public boolean isCloseOnCompletion() throws SQLException {
checkClosedForCompletion();
return closeOnCompletion;
synchronized (stateLock) {
checkClosedForCompletion();
return closeOnCompletion;
}
}

private void checkClosedForCompletion() throws SQLException {
Expand Down
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