001/*
002 * (C) Copyright 2006-2017 Nuxeo (http://nuxeo.com/) and others.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *     http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 *
016 * Contributors:
017 *     Florent Guillaume
018 */
019package org.nuxeo.ecm.core.storage.dbs;
020
021import java.io.ByteArrayOutputStream;
022import java.io.IOException;
023import java.io.InputStream;
024import java.io.OutputStream;
025import java.util.Collection;
026import java.util.HashSet;
027import java.util.Set;
028
029import org.nuxeo.ecm.core.pubsub.SerializableInvalidations;
030
031/**
032 * A set of invalidations for a given repository.
033 * <p>
034 * Records both modified and deleted fragments, as well as "parents modified" fragments.
035 *
036 * @since 8.10
037 */
038public class DBSInvalidations implements SerializableInvalidations {
039
040    private static final long serialVersionUID = 1L;
041
042    /**
043     * Maximum number of invalidations kept, after which only {@link #all} is set. This avoids accumulating too many
044     * invalidations in memory, at the expense of more coarse-grained invalidations.
045     */
046    public static final int MAX_SIZE = 10000;
047
048    /**
049     * Used locally when invalidating everything, or when too many invalidations have been received.
050     */
051    public boolean all;
052
053    /** null when empty */
054    public Set<String> ids;
055
056    public DBSInvalidations() {
057    }
058
059    public DBSInvalidations(boolean all) {
060        this.all = all;
061    }
062
063    @Override
064    public boolean isEmpty() {
065        return ids == null && !all;
066    }
067
068    public void clear() {
069        all = false;
070        ids = null;
071    }
072
073    protected void setAll() {
074        all = true;
075        ids = null;
076    }
077
078    protected void checkMaxSize() {
079        if (ids != null && ids.size() > MAX_SIZE) {
080            setAll();
081        }
082    }
083
084    @Override
085    public void add(SerializableInvalidations o) {
086        DBSInvalidations other = (DBSInvalidations) o;
087        if (other == null) {
088            return;
089        }
090        if (all) {
091            return;
092        }
093        if (other.all) {
094            setAll();
095            return;
096        }
097        if (other.ids != null) {
098            if (ids == null) {
099                ids = new HashSet<>();
100            }
101            ids.addAll(other.ids);
102        }
103        checkMaxSize();
104    }
105
106    public void add(String id) {
107        if (all) {
108            return;
109        }
110        if (ids == null) {
111            ids = new HashSet<>();
112        }
113        ids.add(id);
114        checkMaxSize();
115    }
116
117    public void addAll(Collection<String> idsToAdd) {
118        if (all) {
119            return;
120        }
121        if (ids == null) {
122            ids = new HashSet<>(idsToAdd);
123        } else {
124            ids.addAll(idsToAdd);
125        }
126        checkMaxSize();
127    }
128
129    private static final String UTF_8 = "UTF-8";
130
131    private static final int ALL_IDS = (byte) 'A';
132
133    private static final int ID_SEP = (byte) ',';
134
135    @Override
136    public void serialize(OutputStream out) throws IOException {
137        if (all) {
138            out.write(ALL_IDS);
139        } else if (ids != null) {
140            for (String id : ids) {
141                out.write(ID_SEP);
142                out.write(id.getBytes(UTF_8));
143            }
144        }
145    }
146
147    public static DBSInvalidations deserialize(InputStream in) throws IOException {
148        int first = in.read();
149        if (first == -1) {
150            // empty message
151            return null;
152        }
153        DBSInvalidations invalidations = new DBSInvalidations();
154        if (first == ALL_IDS) {
155            invalidations.setAll();
156        } else if (first != ID_SEP) {
157            // invalid message
158            return null;
159        } else {
160            ByteArrayOutputStream baout = new ByteArrayOutputStream(36); // typical uuid size
161            for (;;) {
162                int b = in.read(); // we read from a ByteArrayInputStream so one at a time is ok
163                if (b == ID_SEP || b == -1) {
164                    invalidations.add(baout.toString(UTF_8));
165                    if (b == -1) {
166                        break;
167                    }
168                    baout.reset();
169                } else {
170                    baout.write(b);
171                }
172            }
173        }
174        return invalidations;
175    }
176
177    @Override
178    public String toString() {
179        StringBuilder sb = new StringBuilder(this.getClass().getSimpleName() + '(');
180        if (all) {
181            sb.append("all=true");
182        }
183        if (ids != null) {
184            sb.append("ids=");
185            sb.append(ids);
186        }
187        sb.append(')');
188        return sb.toString();
189    }
190
191}