// Copyright (C) 2014 The Android Open Source Project
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package com.google.gerrit.server.git.validators;

import com.google.gerrit.extensions.annotations.ExtensionPoint;
import com.google.gerrit.reviewdb.client.Project;
import com.google.gerrit.server.validators.ValidationException;

import org.eclipse.jgit.lib.ObjectId;
import org.eclipse.jgit.lib.Repository;
import org.eclipse.jgit.transport.UploadPack;

import java.util.Collection;

/**
 * Listener to provide validation for upload operations.
 *
 * Invoked by Gerrit before it begins to send a pack to the client.
 *
 * Implementors can block the upload operation by throwing a
 * ValidationException. The exception's message text will be reported to
 * the end-user over the client's protocol connection.
 */
@ExtensionPoint
public interface UploadValidationListener {

  /**
   * Validate an upload before it begins.
   *
   * @param repository The repository
   * @param project The project
   * @param remoteHost Remote address/hostname of the user
   * @param up the UploadPack instance being processed
   * @param wants The list of wanted objects. These may be RevObject or
   *        RevCommit if the processor parsed them. Implementors should not rely
   *        on the values being parsed.
   * @param haves The list of common objects. Empty on an initial clone request.
   *        These may be RevObject or RevCommit if the processor parsed them.
   *        Implementors should not rely on the values being parsed.
   * @throws ValidationException to block the upload and send a message
   *         back to the end-user over the client's protocol connection.
   */
  void onPreUpload(Repository repository, Project project,
      String remoteHost, UploadPack up, Collection<? extends ObjectId> wants,
      Collection<? extends ObjectId> haves)
      throws ValidationException;

  /**
   * Invoked before negotiation round is started.
   *
   * @param repository The repository
   * @param project The project
   * @param remoteHost Remote address/hostname of the user
   * @param up the UploadPack instance being processed
   * @param wants The list of wanted objects. These may be RevObject or
   *        RevCommit if the processor parsed them. Implementors should not rely
   *        on the values being parsed.
   * @param cntOffered number of objects the client has offered.
   * @throws ValidationException to block the upload and send a message back to
   *         the end-user over the client's protocol connection.
   */
  void onBeginNegotiate(Repository repository, Project project,
      String remoteHost, UploadPack up, Collection<? extends ObjectId> wants,
      int cntOffered) throws ValidationException;
}