/*******************************************************************************
 * Copyright (c) 2006 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 * Port to the D programming language:
 *     Frank Benoit <benoit@tionex.de>
 *******************************************************************************/
module org.eclipse.core.commands.operations.IOperationApprover2;

import org.eclipse.core.runtime.IAdaptable;
import org.eclipse.core.runtime.IStatus;

import org.eclipse.core.commands.operations.IOperationApprover;
import org.eclipse.core.commands.operations.IUndoableOperation;
import org.eclipse.core.commands.operations.IOperationHistory;

import java.lang.all;

/**
 * Extends {@link IOperationApprover} to approve the execution of a particular
 * operation within an operation history. Operations that are candidates for
 * execution have already been validated against their current state and
 * according to the rules of the history. Prior to 3.2, an operation approver
 * was only consulted for undo and redo of an operation, not its initial
 * execution.
 * <p>
 * By the time an IOperationApprover2 is consulted, the execution has already
 * been requested and it has been determined that the operation is valid.
 * Approvers should return an <code>IStatus</code> object with severity
 * <code>OK</code> if the operation should proceed, and any other severity if
 * it should not. When an operation is not approved, it is expected that the
 * object not allowing the operation has already consulted the user if necessary
 * or otherwise provided any necessary information to the user about the fact
 * that the operation is not approved.
 * </p>
 * <p>
 * Like {@link IOperationApprover}, implementers of this extension must be
 * prepared to receive the approval messages from a background thread. Any UI
 * access occurring inside the implementation must be properly synchronized
 * using the techniques specified by the client's widget library.
 * </p>
 *
 * @since 3.2
 */
public interface IOperationApprover2 : IOperationApprover {
    /**
     * Return a status indicating whether the specified operation should be
     * executed. Any status that does not have severity <code>IStatus.OK</code>
     * will not be approved. Implementers should not assume that the execution
     * will be performed when the status is <code>OK</code>, since other
     * operation approvers may veto the execution.
     *
     * @param operation
     *            the operation to be executed
     * @param history
     *            the history performing the execution of the operation
     * @param info
     *            the IAdaptable (or <code>null</code>) provided by the
     *            caller in order to supply UI information for prompting the
     *            user if necessary. When this parameter is not
     *            <code>null</code>, it should minimally contain an adapter
     *            for the org.eclipse.swt.widgets.Shell.class. Even if UI
     *            information is provided, the implementation of this method
     *            must be prepared for being called from a background thread.
     *            Any UI access must be properly synchronized using the
     *            techniques specified by the client's widget library.
     * @return the IStatus describing whether the operation is approved. The
     *         execution will not proceed if the status severity is not
     *         <code>OK</code>, and the caller requesting the execution will
     *         be returned the status that caused the rejection. Any other
     *         status severities will not be interpreted by the history.
     */
    IStatus proceedExecuting(IUndoableOperation operation,
            IOperationHistory history, IAdaptable info);
}