Bug 161738 [Undo] - API - promote ability to quietly compute status to operations API
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/ide/undo/AbstractWorkspaceOperation.java
* @see #setQuietCompute(boolean)
	 */
	public IStatus computeExecutionStatus(IProgressMonitor monitor) {
		IStatus status = Status.OK_STATUS;
		
		if (quietCompute) {
			return status;
		}
		IResourceChangeDescriptionFactory factory = ResourceChangeValidator
				.getValidator().createDeltaFactory();
		if (updateResourceChangeDescriptionFactory(factory, EXECUTE)) {
			boolean proceed = IDE
					.promptToConfirm(
							getShell(null),
							UndoMessages.AbstractWorkspaceOperation_SideEffectsWarningTitle,
							NLS
									.bind(
											UndoMessages.AbstractWorkspaceOperation_ExecuteSideEffectsWarningMessage,
											getLabel()), factory.getDelta(),
							modelProviderIds, true );
			if (!proceed) {
				status = IOperationHistory.OPERATION_INVALID_STATUS;
				markInvalid();
			}
		}
		return status;
	}
	/**
	 * Return a status indicating the projected outcome of undoing the receiver.
	 * This method is not called by the operation history, but instead is used