From 3903dff3db1cae9e7347cff01191b5ad53416b47 Mon Sep 17 00:00:00 2001
From: Shay Rojansky <roji@roji.org>
Date: Thu, 27 Aug 2020 17:54:08 +0300
Subject: [PATCH] Implement savepoint API for Microsoft.Data.Sqlite

Closes #20228
---
 .../Microsoft.Data.Sqlite.Core.csproj         |  2 +-
 .../SqliteTransaction.cs                      | 92 +++++++++++++++++++
 .../SqliteTransactionTest.cs                  | 20 ++++
 3 files changed, 113 insertions(+), 1 deletion(-)

diff --git a/src/Microsoft.Data.Sqlite.Core/Microsoft.Data.Sqlite.Core.csproj b/src/Microsoft.Data.Sqlite.Core/Microsoft.Data.Sqlite.Core.csproj
index 027520179af..a44c5d0d09c 100644
--- a/src/Microsoft.Data.Sqlite.Core/Microsoft.Data.Sqlite.Core.csproj
+++ b/src/Microsoft.Data.Sqlite.Core/Microsoft.Data.Sqlite.Core.csproj
@@ -15,7 +15,7 @@ Microsoft.Data.Sqlite.SqliteException
 Microsoft.Data.Sqlite.SqliteFactory
 Microsoft.Data.Sqlite.SqliteParameter
 Microsoft.Data.Sqlite.SqliteTransaction</Description>
-    <TargetFramework>netstandard2.0</TargetFramework>
+    <TargetFrameworks>netstandard2.0;net5.0</TargetFrameworks>
     <MinClientVersion>3.6</MinClientVersion>
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
     <CodeAnalysisRuleSet>Microsoft.Data.Sqlite.Core.ruleset</CodeAnalysisRuleSet>
diff --git a/src/Microsoft.Data.Sqlite.Core/SqliteTransaction.cs b/src/Microsoft.Data.Sqlite.Core/SqliteTransaction.cs
index cf6cb9a3201..945b9c2edef 100644
--- a/src/Microsoft.Data.Sqlite.Core/SqliteTransaction.cs
+++ b/src/Microsoft.Data.Sqlite.Core/SqliteTransaction.cs
@@ -4,6 +4,7 @@
 using System;
 using System.Data;
 using System.Data.Common;
+using System.Text;
 using Microsoft.Data.Sqlite.Properties;
 using static SQLitePCL.raw;
 
@@ -113,6 +114,97 @@ public override void Rollback()
             RollbackInternal();
         }
 
+#if NET
+        /// <inheritdoc />
+        public override bool SupportsSavepoints => true;
+#endif
+
+        /// <summary>
+        /// Creates a savepoint in the transaction. This allows all commands that are executed after the savepoint was
+        /// established to be rolled back, restoring the transaction state to what it was at the time of the savepoint.
+        /// </summary>
+        /// <param name="savepointName">The name of the savepoint to be created.</param>
+#if NET
+        public override void Save(string savepointName)
+#else
+        public void Save(string savepointName)
+#endif
+        {
+            if (savepointName is null)
+            {
+                throw new ArgumentNullException(nameof(savepointName));
+            }
+
+            if (_completed || _connection.State != ConnectionState.Open)
+            {
+                throw new InvalidOperationException(Resources.TransactionCompleted);
+            }
+
+            _connection.ExecuteNonQuery(
+                new StringBuilder()
+                    .Append("SAVEPOINT \"")
+                    .Append(savepointName.Replace("\"", "\"\""))
+                    .Append("\";")
+                    .ToString());
+        }
+
+        /// <summary>
+        /// Rolls back all commands that were executed after the specified savepoint was established.
+        /// </summary>
+        /// <param name="savepointName">The name of the savepoint to roll back to.</param>
+#if NET
+        public override void Rollback(string savepointName)
+#else
+        public void Rollback(string savepointName)
+#endif
+        {
+            if (savepointName is null)
+            {
+                throw new ArgumentNullException(nameof(savepointName));
+            }
+
+            if (_completed || _connection.State != ConnectionState.Open)
+            {
+                throw new InvalidOperationException(Resources.TransactionCompleted);
+            }
+
+            _connection.ExecuteNonQuery(
+                new StringBuilder()
+                    .Append("ROLLBACK TO SAVEPOINT \"")
+                    .Append(savepointName.Replace("\"", "\"\""))
+                    .Append("\";")
+                    .ToString());
+        }
+
+        /// <summary>
+        /// Destroys a savepoint previously defined in the current transaction. This allows the system to
+        /// reclaim some resources before the transaction ends.
+        /// </summary>
+        /// <param name="savepointName">The name of the savepoint to release.</param>
+#if NET
+        public override void Release(string savepointName)
+#else
+        public void Release(string savepointName)
+#endif
+        {
+            if (savepointName is null)
+            {
+                throw new ArgumentNullException(nameof(savepointName));
+            }
+
+            if (_completed || _connection.State != ConnectionState.Open)
+            {
+                throw new InvalidOperationException(Resources.TransactionCompleted);
+            }
+
+            _connection.ExecuteNonQuery(
+                new StringBuilder()
+                    .Append("RELEASE SAVEPOINT \"")
+                    .Append(savepointName.Replace("\"", "\"\""))
+                    .Append("\";")
+                    .ToString());
+        }
+
         /// <summary>
         ///     Releases any resources used by the transaction and rolls it back.
         /// </summary>
diff --git a/test/Microsoft.Data.Sqlite.Tests/SqliteTransactionTest.cs b/test/Microsoft.Data.Sqlite.Tests/SqliteTransactionTest.cs
index 522234b0e9e..9e33003fbe5 100644
--- a/test/Microsoft.Data.Sqlite.Tests/SqliteTransactionTest.cs
+++ b/test/Microsoft.Data.Sqlite.Tests/SqliteTransactionTest.cs
@@ -356,6 +356,26 @@ public void Dispose_can_be_called_more_than_once()
             }
         }
 
+        [Fact]
+        public void Savepoint()
+        {
+            using var connection = new SqliteConnection("Data Source=:memory:");
+            connection.Open();
+            CreateTestTable(connection);
+
+            var transaction = connection.BeginTransaction();
+            transaction.Save("MySavepointName");
+
+            connection.ExecuteNonQuery("INSERT INTO TestTable (TestColumn) VALUES (8)");
+            Assert.Equal(1L, connection.ExecuteScalar<long>("SELECT COUNT(*) FROM TestTable;"));
+
+            transaction.Rollback("MySavepointName");
+            Assert.Equal(0L, connection.ExecuteScalar<long>("SELECT COUNT(*) FROM TestTable;"));
+
+            transaction.Release("MySavepointName");
+            Assert.Throws<SqliteException>(() => transaction.Rollback("MySavepointName"));
+        }
+
         private static void CreateTestTable(SqliteConnection connection)
         {
             connection.ExecuteNonQuery(