public int Exec()

in Python/Product/PythonTools/PythonTools/Intellisense/IntellisenseController.cs [1071:1223]
131 lines of code
70 McCabe index (conditional complexity)

        public int Exec(ref Guid pguidCmdGroup, uint nCmdID, uint nCmdexecopt, IntPtr pvaIn, IntPtr pvaOut) {
            var session = Volatile.Read(ref _activeSession);
            ISignatureHelpSession sigHelpSession;

            if (pguidCmdGroup == VSConstants.VSStd2K && nCmdID == (int)VSConstants.VSStd2KCmdID.TYPECHAR) {
                var ch = (char)(ushort)System.Runtime.InteropServices.Marshal.GetObjectForNativeVariant(pvaIn);
                bool suppressChar = false;

                if (session != null && !session.IsDismissed) {
                    if (session.SelectedCompletionSet != null &&
                        session.SelectedCompletionSet.SelectionStatus.IsSelected &&
                        _services.Python.AdvancedOptions.CompletionCommittedBy.IndexOf(ch) != -1) {

                        if ((ch == '\\' || ch == '/') && session.SelectedCompletionSet.Moniker == "PythonFilenames") {
                            // We want to dismiss filename completions on slashes
                            // rather than committing them. Then it will probably
                            // be retriggered after the slash is inserted.
                            session.Dismiss();
                        } else {
                            if (ch == session.SelectedCompletionSet.SelectionStatus.Completion.InsertionText.LastOrDefault()) {
                                suppressChar = true;
                            }
                            session.Commit();
                        }
                    } else if (!Tokenizer.IsIdentifierChar(ch)) {
                        session.Dismiss();
                    }
                }

                int res = VSConstants.S_OK;
                if (!suppressChar) {
                    res = _oldTarget != null ? _oldTarget.Exec(ref pguidCmdGroup, nCmdID, nCmdexecopt, pvaIn, pvaOut) : VSConstants.S_OK;

                    HandleChar(ch);

                    if (session != null && session.IsStarted && !session.IsDismissed) {
                        session.Filter();
                    }
                }

                return res;
            }

            if (session != null) {
                if (pguidCmdGroup == VSConstants.VSStd2K) {
                    switch ((VSConstants.VSStd2KCmdID)nCmdID) {
                        case VSConstants.VSStd2KCmdID.RETURN:
                            if (_services.Python.AdvancedOptions.EnterCommitsIntellisense &&
                                !session.IsDismissed &&
                                (session.SelectedCompletionSet?.SelectionStatus.IsSelected ?? false)) {

                                // If the user has typed all of the characters as the completion and presses
                                // enter we should dismiss & let the text editor receive the enter.  For example 
                                // when typing "import sys[ENTER]" completion starts after the space.  After typing
                                // sys the user wants a new line and doesn't want to type enter twice.

                                bool enterOnComplete = _services.Python.AdvancedOptions.AddNewLineAtEndOfFullyTypedWord &&
                                        EnterOnCompleteText(session);

                                session.Commit();

                                if (!enterOnComplete) {
                                    return VSConstants.S_OK;
                                }
                            } else {
                                session.Dismiss();
                            }

                            break;
                        case VSConstants.VSStd2KCmdID.TAB:
                            if (!session.IsDismissed) {
                                session.Commit();
                                return VSConstants.S_OK;
                            }

                            break;
                        case VSConstants.VSStd2KCmdID.BACKSPACE:
                        case VSConstants.VSStd2KCmdID.DELETE:
                        case VSConstants.VSStd2KCmdID.DELETEWORDLEFT:
                        case VSConstants.VSStd2KCmdID.DELETEWORDRIGHT:
                            int res = _oldTarget != null ? _oldTarget.Exec(ref pguidCmdGroup, nCmdID, nCmdexecopt, pvaIn, pvaOut) : VSConstants.S_OK;
                            if (session != null && session.IsStarted && !session.IsDismissed) {
                                session.Filter();
                            }
                            return res;
                    }
                }
            } else if ((sigHelpSession = Volatile.Read(ref _sigHelpSession)) != null) {
                if (pguidCmdGroup == VSConstants.VSStd2K) {
                    switch ((VSConstants.VSStd2KCmdID)nCmdID) {
                        case VSConstants.VSStd2KCmdID.BACKSPACE:
                            bool fDeleted = Backspace();
                            if (fDeleted) {
                                return VSConstants.S_OK;
                            }
                            break;
                        case VSConstants.VSStd2KCmdID.LEFT:
                            _editOps.MoveToPreviousCharacter(false);
                            UpdateCurrentParameter();
                            return VSConstants.S_OK;
                        case VSConstants.VSStd2KCmdID.RIGHT:
                            _editOps.MoveToNextCharacter(false);
                            UpdateCurrentParameter();
                            return VSConstants.S_OK;
                        case VSConstants.VSStd2KCmdID.HOME:
                        case VSConstants.VSStd2KCmdID.BOL:
                        case VSConstants.VSStd2KCmdID.BOL_EXT:
                        case VSConstants.VSStd2KCmdID.EOL:
                        case VSConstants.VSStd2KCmdID.EOL_EXT:
                        case VSConstants.VSStd2KCmdID.END:
                        case VSConstants.VSStd2KCmdID.WORDPREV:
                        case VSConstants.VSStd2KCmdID.WORDPREV_EXT:
                        case VSConstants.VSStd2KCmdID.DELETEWORDLEFT:
                            sigHelpSession.Dismiss();
                            break;
                    }
                }
            } else {
                if (pguidCmdGroup == VSConstants.VSStd2K) {
                    switch ((VSConstants.VSStd2KCmdID)nCmdID) {
                        case VSConstants.VSStd2KCmdID.RETURN:
                            if (_expansionMgr != null && _expansionClient.InSession && ErrorHandler.Succeeded(_expansionClient.EndCurrentExpansion(false))) {
                                return VSConstants.S_OK;
                            }
                            break;
                        case VSConstants.VSStd2KCmdID.TAB:
                            if (_expansionMgr != null && _expansionClient.InSession && ErrorHandler.Succeeded(_expansionClient.NextField())) {
                                return VSConstants.S_OK;
                            }
                            if (_textView.Selection.IsEmpty && _textView.Caret.Position.BufferPosition > 0) {
                                if (TryTriggerExpansion()) {
                                    return VSConstants.S_OK;
                                }
                            }
                            break;
                        case VSConstants.VSStd2KCmdID.BACKTAB:
                            if (_expansionMgr != null && _expansionClient.InSession && ErrorHandler.Succeeded(_expansionClient.PreviousField())) {
                                return VSConstants.S_OK;
                            }
                            break;
                        case VSConstants.VSStd2KCmdID.SURROUNDWITH:
                        case VSConstants.VSStd2KCmdID.INSERTSNIPPET:
                            TriggerSnippet(nCmdID);
                            return VSConstants.S_OK;
                    }
                }
            }

            if (_oldTarget != null) {
                return _oldTarget.Exec(ref pguidCmdGroup, nCmdID, nCmdexecopt, pvaIn, pvaOut);
            }
            return (int)Constants.OLECMDERR_E_UNKNOWNGROUP;
        }