com.google.gerrit.server.notedb.ChangeNoteJson Maven / Gradle / Ivy
// Copyright (C) 2018 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.collect.ImmutableList;
import com.google.gerrit.entities.EntitiesAdapterFactory;
import com.google.gerrit.entities.SubmitRequirementExpressionResult;
import com.google.gerrit.entities.SubmitRequirementExpressionResult.Status;
import com.google.gerrit.json.EnumTypeAdapterFactory;
import com.google.gerrit.json.OptionalSubmitRequirementExpressionResultAdapterFactory;
import com.google.gerrit.json.OptionalTypeAdapter;
import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.JsonElement;
import com.google.gson.JsonObject;
import com.google.gson.JsonParser;
import com.google.gson.TypeAdapter;
import com.google.gson.stream.JsonReader;
import com.google.gson.stream.JsonWriter;
import com.google.inject.Singleton;
import com.google.inject.TypeLiteral;
import java.io.IOException;
import java.sql.Timestamp;
import java.util.Arrays;
import java.util.List;
import java.util.Optional;
import org.eclipse.jgit.lib.ObjectId;
/**
* Provides {@link Gson} to parse {@link ChangeRevisionNote}, attached to the change update.
*
* Apart from the adapters for the custom JSON format, this class also registers adapters that
* support forward/backward compatibility when modifying {@link ChangeNotes} storage format.
*
*
NOTE: All changes to the storage format must be both forward and backward compatible, see
* comment on {@link ChangeNotesParser}.
*
*
For JSON, such changes include e.g. modifications to the serialized {@code AutoValue} classes.
*/
@Singleton
public class ChangeNoteJson {
private final Gson gson = newGson();
static Gson newGson() {
return new GsonBuilder()
.registerTypeAdapter(Optional.class, new OptionalTypeAdapter())
.registerTypeAdapter(Timestamp.class, new CommentTimestampAdapter().nullSafe())
.registerTypeAdapterFactory(new EnumTypeAdapterFactory())
.registerTypeAdapterFactory(EntitiesAdapterFactory.create())
.registerTypeAdapter(
new TypeLiteral>() {}.getType(),
new ImmutableListAdapter().nullSafe())
.registerTypeAdapter(
new TypeLiteral>() {}.getType(),
new OptionalBooleanAdapter().nullSafe())
.registerTypeAdapterFactory(new OptionalSubmitRequirementExpressionResultAdapterFactory())
.registerTypeAdapter(ObjectId.class, new ObjectIdAdapter())
.registerTypeAdapter(
SubmitRequirementExpressionResult.Status.class,
new SubmitRequirementExpressionResultStatusAdapter())
.setPrettyPrinting()
.create();
}
public Gson getGson() {
return gson;
}
static class OptionalBooleanAdapter extends TypeAdapter> {
@Override
public void write(JsonWriter out, Optional value) throws IOException {
// Serialize the field using the same format used by the AutoValue's default Gson serializer.
out.beginObject();
out.name("value");
if (value.isPresent()) {
out.value(value.get());
} else {
out.nullValue();
}
out.endObject();
}
@Override
public Optional read(JsonReader in) throws IOException {
JsonElement parsed = JsonParser.parseReader(in);
if (parsed == null) {
return Optional.empty();
}
if (parsed.isJsonObject()) {
// If it's not a JSON object, then the boolean value is available directly in the Json
// element.
parsed = parsed.getAsJsonObject().get("value");
}
if (parsed == null || parsed.isJsonNull()) {
return Optional.empty();
}
return Optional.of(parsed.getAsBoolean());
}
}
/** Json serializer for the {@link ObjectId} class. */
static class ObjectIdAdapter extends TypeAdapter {
private static final List legacyFields = Arrays.asList("w1", "w2", "w3", "w4", "w5");
@Override
public void write(JsonWriter out, ObjectId value) throws IOException {
out.value(value.name());
}
@Override
public ObjectId read(JsonReader in) throws IOException {
JsonElement parsed = JsonParser.parseReader(in);
if (parsed.isJsonObject() && isJGitFormat(parsed)) {
// Some object IDs may have been serialized using the JGit format using the five integers
// w1, w2, w3, w4, w5. Detect this case so that we can deserialize properly.
int[] raw =
legacyFields.stream()
.mapToInt(field -> parsed.getAsJsonObject().get(field).getAsInt())
.toArray();
return ObjectId.fromRaw(raw);
}
return ObjectId.fromString(parsed.getAsString());
}
/** Return true if the json element contains the JGit serialized format of the Object ID. */
private boolean isJGitFormat(JsonElement elem) {
JsonObject asObj = elem.getAsJsonObject();
return legacyFields.stream().allMatch(field -> asObj.has(field));
}
}
static class ImmutableListAdapter extends TypeAdapter> {
@Override
public void write(JsonWriter out, ImmutableList value) throws IOException {
out.beginArray();
for (String v : value) {
out.value(v);
}
out.endArray();
}
@Override
public ImmutableList read(JsonReader in) throws IOException {
ImmutableList.Builder builder = ImmutableList.builder();
in.beginArray();
while (in.hasNext()) {
builder.add(in.nextString());
}
in.endArray();
return builder.build();
}
}
/**
* A Json type adapter for the Status enum in {@link SubmitRequirementExpressionResult}. This
* adapter is able to parse unrecognized values. Unrecognized values are converted to the value
* "ERROR" The adapter is needed to ensure forward compatibility since we want to add more values
* to this enum. We do that to ensure safer rollout in distributed setups where some tasks are
* updated before others. We make sure that tasks running the old binaries are still able to parse
* values written by tasks running the new binaries.
*
* TODO(ghareeb): Remove this adapter.
*/
static class SubmitRequirementExpressionResultStatusAdapter
extends TypeAdapter {
@Override
public void write(JsonWriter jsonWriter, Status status) throws IOException {
jsonWriter.value(status.name());
}
@Override
public Status read(JsonReader jsonReader) throws IOException {
String val = jsonReader.nextString();
try {
return SubmitRequirementExpressionResult.Status.valueOf(val);
} catch (IllegalArgumentException e) {
return SubmitRequirementExpressionResult.Status.ERROR;
}
}
}
}