1 files changed, 58 insertions, 0 deletions
diff --git a/src/Text/Def/TextUI/Utilities/IUIThreadOperationContext.cs b/src/Text/Def/TextUI/Utilities/IUIThreadOperationContext.cs
new file mode 100644
index 0000000..fce50d4
--- /dev/null
+++ b/src/Text/Def/TextUI/Utilities/IUIThreadOperationContext.cs
@@ -0,0 +1,58 @@
+using System;
+using System.Collections.Generic;
+using System.Threading;
+
+namespace Microsoft.VisualStudio.Utilities
+{
+    /// <summary>
+    /// Represents a context of executing potentially long running operation on the UI thread, which
+    /// enables shared two way cancellability and wait indication.
+    /// </summary>
+    /// <remarks>
+    /// Instances implementing this interface are produced by <see cref="IUIThreadOperationExecutor"/>
+    /// MEF component.
+    /// </remarks>
+    public interface IUIThreadOperationContext : IPropertyOwner, IDisposable
+    {
+        /// <summary>
+        /// Cancellation token that allows user to cancel the operation unless the operation
+        /// is not cancellable.
+        /// </summary>
+        CancellationToken UserCancellationToken { get; }
+
+        /// <summary>
+        /// Gets whether the operation can be cancelled.
+        /// </summary>
+        /// <remarks>This value is composed of initial AllowCancellation value and
+        /// <see cref="IUIThreadOperationScope.AllowCancellation"/> values of all currently added scopes.
+        /// The value composition logic takes into acount disposed scopes too - if any of added scopes
+        /// were disposed while its <see cref="IUIThreadOperationScope.AllowCancellation"/> was false,
+        /// this property will stay false regardless of all other scopes' <see cref="IUIThreadOperationScope.AllowCancellation"/>
+        /// values.
+        /// </remarks>
+        bool AllowCancellation { get; }
+
+        /// <summary>
+        /// Gets user readable operation description, composed of initial context description and
+        /// descriptions of all currently added scopes.
+        /// </summary>
+        string Description { get; }
+
+        /// <summary>
+        /// Gets current list of <see cref="IUIThreadOperationScope"/>s in this context.
+        /// </summary>
+        IEnumerable<IUIThreadOperationScope> Scopes { get; }
+
+        /// <summary>
+        /// Adds a UI thread operation scope with its own two way cancellability, description and progress tracker.
+        /// The scope is removed from the context on dispose.
+        /// </summary>
+        IUIThreadOperationScope AddScope(bool allowCancellation, string description);
+
+        /// <summary>
+        /// Allows a component to take full ownership over this UI thread operation, for example
+        /// when it shows its own modal UI dialog and handles cancellability through that dialog instead.
+        /// </summary>
+        void TakeOwnership();
+    }
+}