gerrit-server/src/main/java/com/google/gerrit/server/notedb/DraftCommentNotes.java

// 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.notedb;

import com.google.common.annotations.VisibleForTesting;
import com.google.common.collect.ArrayListMultimap;
import com.google.common.collect.ImmutableListMultimap;
import com.google.common.collect.Multimap;
import com.google.gerrit.reviewdb.client.Account;
import com.google.gerrit.reviewdb.client.Change;
import com.google.gerrit.reviewdb.client.PatchLineComment;
import com.google.gerrit.reviewdb.client.Project;
import com.google.gerrit.reviewdb.client.RefNames;
import com.google.gerrit.reviewdb.client.RevId;
import com.google.gerrit.server.git.RepoRefCache;
import com.google.gerrit.server.project.NoSuchChangeException;
import com.google.gwtorm.server.OrmException;
import com.google.inject.assistedinject.Assisted;
import com.google.inject.assistedinject.AssistedInject;

import org.eclipse.jgit.errors.ConfigInvalidException;
import org.eclipse.jgit.lib.ObjectId;
import org.eclipse.jgit.lib.ObjectReader;
import org.eclipse.jgit.lib.Repository;
import org.eclipse.jgit.notes.NoteMap;
import org.eclipse.jgit.revwalk.RevCommit;

import java.io.IOException;

/**
 * View of the draft comments for a single {@link Change} based on the log of
 * its drafts branch.
 */
public class DraftCommentNotes extends AbstractChangeNotes<DraftCommentNotes> {
  public interface Factory {
    DraftCommentNotes create(Change change, Account.Id accountId);
    DraftCommentNotes createWithAutoRebuildingDisabled(
        Change.Id changeId, Account.Id accountId);
  }

  private final Change change;
  private final Account.Id author;
  private final boolean autoRebuild;

  private ImmutableListMultimap<RevId, PatchLineComment> comments;
  private RevisionNoteMap revisionNoteMap;

  @AssistedInject
  DraftCommentNotes(
      Args args,
      @Assisted Change change,
      @Assisted Account.Id author) {
    this(args, change, author, true);
  }

  @AssistedInject
  DraftCommentNotes(
      Args args,
      @Assisted Change.Id changeId,
      @Assisted Account.Id author) {
    super(args, changeId);
    this.change = null;
    this.author = author;
    this.autoRebuild = true;
  }

  DraftCommentNotes(
      Args args,
      Change change,
      Account.Id author,
      boolean autoRebuild) {
    super(args, change.getId());
    this.change = change;
    this.author = author;
    this.autoRebuild = autoRebuild;
  }

  RevisionNoteMap getRevisionNoteMap() {
    return revisionNoteMap;
  }

  public Account.Id getAuthor() {
    return author;
  }

  public ImmutableListMultimap<RevId, PatchLineComment> getComments() {
    // TODO(dborowitz): Defensive copy?
    return comments;
  }

  public boolean containsComment(PatchLineComment c) {
    for (PatchLineComment existing : comments.values()) {
      if (c.getKey().equals(existing.getKey())) {
        return true;
      }
    }
    return false;
  }

  @Override
  protected String getRefName() {
    return RefNames.refsDraftComments(getChangeId(), author);
  }

  @Override
  protected void onLoad(LoadHandle handle)
      throws IOException, ConfigInvalidException {
    ObjectId rev = handle.id();
    if (rev == null) {
      loadDefaults();
      return;
    }

    RevCommit tipCommit = handle.walk().parseCommit(rev);
    ObjectReader reader = handle.walk().getObjectReader();
    revisionNoteMap = RevisionNoteMap.parse(
        args.noteUtil, getChangeId(), reader, NoteMap.read(reader, tipCommit),
        true);
    Multimap<RevId, PatchLineComment> cs = ArrayListMultimap.create();
    for (RevisionNote rn : revisionNoteMap.revisionNotes.values()) {
      for (PatchLineComment c : rn.comments) {
        cs.put(c.getRevId(), c);
      }
    }
    comments = ImmutableListMultimap.copyOf(cs);
  }

  @Override
  protected void loadDefaults() {
    comments = ImmutableListMultimap.of();
  }

  @Override
  public Project.NameKey getProjectName() {
    return args.allUsers;
  }

  @Override
  protected LoadHandle openHandle(Repository repo) throws IOException {
    if (change != null && autoRebuild) {
      NoteDbChangeState state = NoteDbChangeState.parse(change);
      // Only check if this particular user's drafts are up to date, to avoid
      // reading unnecessary refs.
      if (!NoteDbChangeState.areDraftsUpToDate(
          state, new RepoRefCache(repo), getChangeId(), author)) {
        return rebuildAndOpen(repo);
      }
    }
    return super.openHandle(repo);
  }

  private LoadHandle rebuildAndOpen(Repository repo) throws IOException {
    try {
      NoteDbChangeState newState =
          args.rebuilder.get().rebuild(args.db.get(), getChangeId());
      if (newState == null) {
        return super.openHandle(repo); // May be null in tests.
      }
      ObjectId draftsId = newState.getDraftIds().get(author);
      repo.scanForRepoChanges();
      return LoadHandle.create(ChangeNotesCommit.newRevWalk(repo), draftsId);
    } catch (NoSuchChangeException e) {
      return super.openHandle(repo);
    } catch (OrmException | ConfigInvalidException e) {
      throw new IOException(e);
    }
  }

  @VisibleForTesting
  NoteMap getNoteMap() {
    return revisionNoteMap != null ? revisionNoteMap.noteMap : null;
  }
}