Microsoft.VisualStudio.Project.NestedProjectNode.LockRdtEntry C# (CSharp) Method

        protected virtual void LockRdtEntry()
        {
            // Define flags for the nested project document
            _VSRDTFLAGS flags = _VSRDTFLAGS.RDT_VirtualDocument | _VSRDTFLAGS.RDT_ProjSlnDocument; ;

            // Request the RDT service
            IVsRunningDocumentTable rdt = this.GetService(typeof(SVsRunningDocumentTable)) as IVsRunningDocumentTable;
            Debug.Assert(rdt != null, " Could not get running document table from the services exposed by this project");
            if (rdt == null)
            {
                throw new InvalidOperationException();
            }

            // First we see if someone else has opened the requested view of the file.
            uint itemid;
            IntPtr docData = IntPtr.Zero;
            IVsHierarchy ivsHierarchy;
            uint docCookie;
            IntPtr projectPtr = IntPtr.Zero;

            try
            {
                ErrorHandler.ThrowOnFailure(rdt.FindAndLockDocument((uint)flags, this.ProjectPath, out ivsHierarchy, out itemid, out docData, out docCookie));
                flags |= _VSRDTFLAGS.RDT_EditLock;

                if (ivsHierarchy != null && docCookie != (uint)ShellConstants.VSDOCCOOKIE_NIL)
                {
                    if (docCookie != this.DocCookie)
                    {
                        this.DocCookie = docCookie;
                    }
                }
                else
                {

                    // get inptr for hierarchy
                    projectPtr = Marshal.GetIUnknownForObject(this.nestedHierarchy);
                    Debug.Assert(projectPtr != IntPtr.Zero, " Project pointer for the nested hierarchy has not been initialized");
                    ErrorHandler.ThrowOnFailure(rdt.RegisterAndLockDocument((uint)flags, this.ProjectPath, this.ProjectManager.InteropSafeIVsHierarchy, this.Id, projectPtr, out docCookie));

                    this.DocCookie = docCookie;
                    Debug.Assert(this.DocCookie != (uint)ShellConstants.VSDOCCOOKIE_NIL, "Invalid cookie when registering document in the running document table.");

                    //we must also set the doc cookie on the nested hier
                    this.SetDocCookieOnNestedHier(this.DocCookie);
                }
            }
            finally
            {
                // Release all IntPtr's that were given as out pointers
                if (docData != IntPtr.Zero)
                {
                    Marshal.Release(docData);
                }
                if (projectPtr != IntPtr.Zero)
                {
                    Marshal.Release(projectPtr);
                }
            }
        }