com.google.gerrit.server.change.ChangeResource.java Source code

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Here is the source code for com.google.gerrit.server.change.ChangeResource.java

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// Copyright (C) 2012 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.change;

import static java.nio.charset.StandardCharsets.UTF_8;

import com.google.common.base.MoreObjects;
import com.google.common.hash.Hasher;
import com.google.common.hash.Hashing;
import com.google.gerrit.extensions.restapi.RestResource;
import com.google.gerrit.extensions.restapi.RestResource.HasETag;
import com.google.gerrit.extensions.restapi.RestView;
import com.google.gerrit.reviewdb.client.AccountGroup;
import com.google.gerrit.reviewdb.client.Change;
import com.google.gerrit.reviewdb.client.Project;
import com.google.gerrit.server.CurrentUser;
import com.google.gerrit.server.IdentifiedUser;
import com.google.gerrit.server.StarredChangesUtil;
import com.google.gerrit.server.notedb.ChangeNotes;
import com.google.gerrit.server.permissions.PermissionBackend;
import com.google.gerrit.server.project.ChangeControl;
import com.google.gerrit.server.project.ProjectState;
import com.google.gwtorm.server.OrmException;
import com.google.inject.Inject;
import com.google.inject.TypeLiteral;
import com.google.inject.assistedinject.Assisted;
import org.eclipse.jgit.lib.ObjectId;

public class ChangeResource implements RestResource, HasETag {
    /**
     * JSON format version number for ETag computations.
     *
     * <p>Should be bumped on any JSON format change (new fields, etc.) so that otherwise unmodified
     * changes get new ETags.
     */
    public static final int JSON_FORMAT_VERSION = 1;

    public static final TypeLiteral<RestView<ChangeResource>> CHANGE_KIND = new TypeLiteral<RestView<ChangeResource>>() {
    };

    public interface Factory {
        ChangeResource create(ChangeControl ctl);
    }

    private final PermissionBackend permissionBackend;
    private final StarredChangesUtil starredChangesUtil;
    private final ChangeControl control;

    @Inject
    ChangeResource(PermissionBackend permissionBackend, StarredChangesUtil starredChangesUtil,
            @Assisted ChangeControl control) {
        this.permissionBackend = permissionBackend;
        this.starredChangesUtil = starredChangesUtil;
        this.control = control;
    }

    public PermissionBackend.ForChange permissions() {
        return permissionBackend.user(getControl().getUser()).change(getNotes());
    }

    public ChangeControl getControl() {
        return control;
    }

    public IdentifiedUser getUser() {
        return getControl().getUser().asIdentifiedUser();
    }

    public Change.Id getId() {
        return getControl().getId();
    }

    public Change getChange() {
        return getControl().getChange();
    }

    public Project.NameKey getProject() {
        return getChange().getProject();
    }

    public ChangeNotes getNotes() {
        return getControl().getNotes();
    }

    // This includes all information relevant for ETag computation
    // unrelated to the UI.
    public void prepareETag(Hasher h, CurrentUser user) {
        h.putInt(JSON_FORMAT_VERSION).putLong(getChange().getLastUpdatedOn().getTime())
                .putInt(getChange().getRowVersion())
                .putInt(user.isIdentifiedUser() ? user.getAccountId().get() : 0);

        if (user.isIdentifiedUser()) {
            for (AccountGroup.UUID uuid : user.getEffectiveGroups().getKnownGroups()) {
                h.putBytes(uuid.get().getBytes(UTF_8));
            }
        }

        byte[] buf = new byte[20];
        ObjectId noteId;
        try {
            noteId = getNotes().loadRevision();
        } catch (OrmException e) {
            noteId = null; // This ETag will be invalidated if it loads next time.
        }
        hashObjectId(h, noteId, buf);
        // TODO(dborowitz): Include more NoteDb and other related refs, e.g. drafts
        // and edits.

        for (ProjectState p : control.getProjectControl().getProjectState().tree()) {
            hashObjectId(h, p.getConfig().getRevision(), buf);
        }
    }

    @Override
    public String getETag() {
        CurrentUser user = control.getUser();
        Hasher h = Hashing.md5().newHasher();
        if (user.isIdentifiedUser()) {
            h.putString(starredChangesUtil.getObjectId(user.getAccountId(), getId()).name(), UTF_8);
        }
        prepareETag(h, user);
        return h.hash().toString();
    }

    private void hashObjectId(Hasher h, ObjectId id, byte[] buf) {
        MoreObjects.firstNonNull(id, ObjectId.zeroId()).copyRawTo(buf, 0);
        h.putBytes(buf);
    }
}