feat: support Savepoint (#1212)

* feat: support Savepoint

Add support for emulated Savepoints that are now supported in the client
library.

* fix: clirr check

clirr-ignored-differences.xml

@@ -6,4 +6,14 @@
     <className>com/google/cloud/spanner/jdbc/CloudSpannerJdbcConnection</className>
     <method>com.google.cloud.spanner.Dialect getDialect()</method>
   </difference>
+  <difference>
+    <differenceType>7012</differenceType>
+    <className>com/google/cloud/spanner/jdbc/CloudSpannerJdbcConnection</className>
+    <method>com.google.cloud.spanner.connection.SavepointSupport getSavepointSupport()</method>
+  </difference>
+  <difference>
+    <differenceType>7012</differenceType>
+    <className>com/google/cloud/spanner/jdbc/CloudSpannerJdbcConnection</className>
+    <method>void setSavepointSupport(com.google.cloud.spanner.connection.SavepointSupport)</method>
+  </difference>
 </differences>

src/main/java/com/google/cloud/spanner/jdbc/AbstractJdbcConnection.java

@@ -28,7 +28,6 @@
 import java.sql.SQLException;
 import java.sql.SQLWarning;
 import java.sql.SQLXML;
-import java.sql.Savepoint;
 import java.sql.Struct;
 import java.util.Properties;
 import java.util.concurrent.Executor;
@@ -42,7 +41,6 @@ abstract class AbstractJdbcConnection extends AbstractJdbcWrapper
       "Only isolation level TRANSACTION_SERIALIZABLE is supported";
   private static final String ONLY_CLOSE_ALLOWED =
       "Only holdability CLOSE_CURSORS_AT_COMMIT is supported";
-  private static final String SAVEPOINTS_UNSUPPORTED = "Savepoints are not supported";
   private static final String SQLXML_UNSUPPORTED = "SQLXML is not supported";
   private static final String STRUCTS_UNSUPPORTED = "Structs are not supported";
   private static final String ABORT_UNSUPPORTED = "Abort is not supported";
@@ -163,26 +161,6 @@ public void clearWarnings() throws SQLException {
     lastWarning = null;
   }
 
-  @Override
-  public Savepoint setSavepoint() throws SQLException {
-    return checkClosedAndThrowUnsupported(SAVEPOINTS_UNSUPPORTED);
-  }
-
-  @Override
-  public Savepoint setSavepoint(String name) throws SQLException {
-    return checkClosedAndThrowUnsupported(SAVEPOINTS_UNSUPPORTED);
-  }
-
-  @Override
-  public void rollback(Savepoint savepoint) throws SQLException {
-    checkClosedAndThrowUnsupported(SAVEPOINTS_UNSUPPORTED);
-  }
-
-  @Override
-  public void releaseSavepoint(Savepoint savepoint) throws SQLException {
-    checkClosedAndThrowUnsupported(SAVEPOINTS_UNSUPPORTED);
-  }
-
   @Override
   public SQLXML createSQLXML() throws SQLException {
     return checkClosedAndThrowUnsupported(SQLXML_UNSUPPORTED);

src/main/java/com/google/cloud/spanner/jdbc/CloudSpannerJdbcConnection.java

@@ -25,6 +25,7 @@
 import com.google.cloud.spanner.ResultSet;
 import com.google.cloud.spanner.TimestampBound;
 import com.google.cloud.spanner.connection.AutocommitDmlMode;
+import com.google.cloud.spanner.connection.SavepointSupport;
 import com.google.cloud.spanner.connection.TransactionMode;
 import java.sql.Connection;
 import java.sql.SQLException;
@@ -256,6 +257,12 @@ default String getStatementTag() throws SQLException {
    */
   void setRetryAbortsInternally(boolean retryAbortsInternally) throws SQLException;
 
+  /** Returns the current savepoint support for this connection. */
+  SavepointSupport getSavepointSupport() throws SQLException;
+
+  /** Sets how savepoints should be supported on this connection. */
+  void setSavepointSupport(SavepointSupport savepointSupport) throws SQLException;
+
   /**
    * Writes the specified mutation directly to the database and commits the change. The value is
    * readable after the successful completion of this method. Writing multiple mutations to a

src/main/java/com/google/cloud/spanner/jdbc/JdbcConnection.java

@@ -23,6 +23,7 @@
 import com.google.cloud.spanner.TimestampBound;
 import com.google.cloud.spanner.connection.AutocommitDmlMode;
 import com.google.cloud.spanner.connection.ConnectionOptions;
+import com.google.cloud.spanner.connection.SavepointSupport;
 import com.google.cloud.spanner.connection.TransactionMode;
 import com.google.common.collect.Iterators;
 import java.sql.Array;
@@ -33,6 +34,7 @@
 import java.sql.PreparedStatement;
 import java.sql.ResultSet;
 import java.sql.SQLException;
+import java.sql.Savepoint;
 import java.sql.Statement;
 import java.sql.Timestamp;
 import java.util.HashMap;
@@ -402,6 +404,70 @@ public String getSchema() throws SQLException {
     return "";
   }
 
+  @Override
+  public SavepointSupport getSavepointSupport() throws SQLException {
+    checkClosed();
+    return getSpannerConnection().getSavepointSupport();
+  }
+
+  @Override
+  public void setSavepointSupport(SavepointSupport savepointSupport) throws SQLException {
+    checkClosed();
+    try {
+      getSpannerConnection().setSavepointSupport(savepointSupport);
+    } catch (SpannerException e) {
+      throw JdbcSqlExceptionFactory.of(e);
+    }
+  }
+
+  @Override
+  public Savepoint setSavepoint() throws SQLException {
+    checkClosed();
+    try {
+      JdbcSavepoint savepoint = JdbcSavepoint.unnamed();
+      getSpannerConnection().savepoint(savepoint.internalGetSavepointName());
+      return savepoint;
+    } catch (SpannerException e) {
+      throw JdbcSqlExceptionFactory.of(e);
+    }
+  }
+
+  @Override
+  public Savepoint setSavepoint(String name) throws SQLException {
+    checkClosed();
+    try {
+      JdbcSavepoint savepoint = JdbcSavepoint.named(name);
+      getSpannerConnection().savepoint(savepoint.internalGetSavepointName());
+      return savepoint;
+    } catch (SpannerException e) {
+      throw JdbcSqlExceptionFactory.of(e);
+    }
+  }
+
+  @Override
+  public void rollback(Savepoint savepoint) throws SQLException {
+    checkClosed();
+    JdbcPreconditions.checkArgument(savepoint instanceof JdbcSavepoint, savepoint);
+    JdbcSavepoint jdbcSavepoint = (JdbcSavepoint) savepoint;
+    try {
+      getSpannerConnection().rollbackToSavepoint(jdbcSavepoint.internalGetSavepointName());
+    } catch (SpannerException e) {
+      throw JdbcSqlExceptionFactory.of(e);
+    }
+  }
+
+  @Override
+  public void releaseSavepoint(Savepoint savepoint) throws SQLException {
+    checkClosed();
+    JdbcPreconditions.checkArgument(savepoint instanceof JdbcSavepoint, savepoint);
+    JdbcSavepoint jdbcSavepoint = (JdbcSavepoint) savepoint;
+    try {
+      getSpannerConnection().releaseSavepoint(jdbcSavepoint.internalGetSavepointName());
+    } catch (SpannerException e) {
+      throw JdbcSqlExceptionFactory.of(e);
+    }
+  }
+
   @Override
   public Timestamp getCommitTimestamp() throws SQLException {
     checkClosed();

src/main/java/com/google/cloud/spanner/jdbc/JdbcSavepoint.java

@@ -0,0 +1,58 @@
+/*
+ * Copyright 2023 Google LLC
+ *
+ * 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 com.google.cloud.spanner.jdbc;
+
+import java.sql.SQLException;
+import java.sql.Savepoint;
+import java.util.concurrent.atomic.AtomicInteger;
+
+class JdbcSavepoint implements Savepoint {
+  private static final AtomicInteger COUNTER = new AtomicInteger();
+
+  static JdbcSavepoint named(String name) {
+    return new JdbcSavepoint(-1, name);
+  }
+
+  static JdbcSavepoint unnamed() {
+    int id = COUNTER.incrementAndGet();
+    return new JdbcSavepoint(id, String.format("s_%d", id));
+  }
+
+  private final int id;
+  private final String name;
+
+  private JdbcSavepoint(int id, String name) {
+    this.id = id;
+    this.name = name;
+  }
+
+  @Override
+  public int getSavepointId() throws SQLException {
+    JdbcPreconditions.checkState(this.id >= 0, "This is a named savepoint");
+    return id;
+  }
+
+  @Override
+  public String getSavepointName() throws SQLException {
+    JdbcPreconditions.checkState(this.id < 0, "This is an unnamed savepoint");
+    return name;
+  }
+
+  String internalGetSavepointName() {
+    return name;
+  }
+}

src/test/java/com/google/cloud/spanner/jdbc/JdbcSavepointTest.java

@@ -0,0 +1,47 @@
+/*
+ * Copyright 2023 Google LLC
+ *
+ * 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 com.google.cloud.spanner.jdbc;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertThrows;
+import static org.junit.Assert.assertTrue;
+
+import java.sql.SQLException;
+import java.sql.Savepoint;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.JUnit4;
+
+@RunWith(JUnit4.class)
+public class JdbcSavepointTest {
+
+  @Test
+  public void testNamed() throws SQLException {
+    Savepoint savepoint = JdbcSavepoint.named("test");
+    assertEquals("test", savepoint.getSavepointName());
+    assertThrows(SQLException.class, savepoint::getSavepointId);
+  }
+
+  @Test
+  public void testUnnamed() throws SQLException {
+    Savepoint savepoint = JdbcSavepoint.unnamed();
+    assertTrue(
+        String.format("Savepoint id: %d", savepoint.getSavepointId()),
+        savepoint.getSavepointId() > 0);
+    assertThrows(SQLException.class, savepoint::getSavepointName);
+  }
+}