Add savepoint API to DbTransaction (#34561)

Closes #33397
dotnet · Aug 5, 2020 · 8250b0a · 8250b0a
1 parent 890fe97
commit 8250b0a
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diff --git a/src/libraries/System.Data.Common/ref/System.Data.Common.cs b/src/libraries/System.Data.Common/ref/System.Data.Common.cs
@@ -2441,6 +2441,13 @@ protected virtual void Dispose(bool disposing) { }
         public virtual System.Threading.Tasks.ValueTask DisposeAsync() { throw null; }
         public abstract void Rollback();
         public virtual System.Threading.Tasks.Task RollbackAsync(System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken)) { throw null; }
+        public virtual bool SupportsSavepoints { get { throw null; } }
+        public virtual System.Threading.Tasks.Task SaveAsync(string savepointName, System.Threading.CancellationToken cancellationToken = default) { throw null; }
+        public virtual System.Threading.Tasks.Task RollbackAsync(string savepointName, System.Threading.CancellationToken cancellationToken = default) { throw null; }
+        public virtual System.Threading.Tasks.Task ReleaseAsync(string savepointName, System.Threading.CancellationToken cancellationToken = default) { throw null; }
+        public virtual void Save(string savepointName) { throw null; }
+        public virtual void Rollback(string savepointName) { throw null; }
+        public virtual void Release(string savepointName) { throw null; }
     }
     public enum GroupByBehavior
     {

diff --git a/src/libraries/System.Data.Common/src/System/Data/Common/DbTransaction.cs b/src/libraries/System.Data.Common/src/System/Data/Common/DbTransaction.cs
@@ -67,5 +67,121 @@ public virtual Task RollbackAsync(CancellationToken cancellationToken = default)
                 return Task.FromException(e);
             }
         }
+
+        #region Savepoints
+
+        /// <summary>
+        /// Gets a value that indicates whether this <see cref="DbTransaction" /> instance supports database savepoints.
+        /// If <see langword="false" />, the methods <see cref="SaveAsync" />,
+        /// <see cref="RollbackAsync(string, System.Threading.CancellationToken)"/> and <see cref="ReleaseAsync" /> as
+        /// well as their synchronous counterparts are expected to throw <see cref="NotSupportedException" />.
+        /// </summary>
+        /// <returns>
+        /// <see langword="true" /> if this <see cref="DbTransaction"/> instance supports database savepoints; otherwise,
+        /// <see langword="false" />.
+        /// </returns>
+        public virtual bool SupportsSavepoints => false;
+
+        /// <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>
+        /// <param name="cancellationToken">
+        /// An optional token to cancel the asynchronous operation. The default value is <see cref="CancellationToken.None" />.
+        /// </param>
+        /// <returns>A <see cref="Task " /> representing the asynchronous operation.</returns>
+        public virtual Task SaveAsync(string savepointName, CancellationToken cancellationToken = default)
+        {
+            if (cancellationToken.IsCancellationRequested)
+            {
+                return Task.FromCanceled(cancellationToken);
+            }
+
+            try
+            {
+                Save(savepointName);
+                return Task.CompletedTask;
+            }
+            catch (Exception e)
+            {
+                return Task.FromException(e);
+            }
+        }
+
+        /// <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>
+        /// <param name="cancellationToken">
+        /// An optional token to cancel the asynchronous operation. The default value is <see cref="CancellationToken.None" />.
+        /// </param>
+        /// <returns>A <see cref="Task " /> representing the asynchronous operation.</returns>
+        public virtual Task RollbackAsync(string savepointName, CancellationToken cancellationToken = default)
+        {
+            if (cancellationToken.IsCancellationRequested)
+            {
+                return Task.FromCanceled(cancellationToken);
+            }
+
+            try
+            {
+                Rollback(savepointName);
+                return Task.CompletedTask;
+            }
+            catch (Exception e)
+            {
+                return Task.FromException(e);
+            }
+        }
+
+        /// <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>
+        /// <param name="cancellationToken">
+        /// An optional token to cancel the asynchronous operation. The default value is <see cref="CancellationToken.None" />.
+        /// </param>
+        /// <returns>A <see cref="Task " /> representing the asynchronous operation.</returns>
+        public virtual Task ReleaseAsync(string savepointName, CancellationToken cancellationToken = default)
+        {
+            if (cancellationToken.IsCancellationRequested)
+            {
+                return Task.FromCanceled(cancellationToken);
+            }
+
+            try
+            {
+                Release(savepointName);
+                return Task.CompletedTask;
+            }
+            catch (Exception e)
+            {
+                return Task.FromException(e);
+            }
+        }
+
+        /// <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>
+        public virtual void Save(string savepointName) => throw new NotSupportedException();
+
+        /// <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>
+        public virtual void Rollback(string savepointName) => throw new NotSupportedException();
+
+        /// <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>
+        public virtual void Release(string savepointName) {}
+
+        #endregion
     }
 }