/*
* Copyright 2012-present Facebook, Inc.
*
* 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.facebook.buck.json;
import com.facebook.buck.util.ImmutableMapWithNullValues;
import com.fasterxml.jackson.core.JsonParseException;
import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.core.JsonToken;
import com.fasterxml.jackson.databind.DeserializationContext;
import com.fasterxml.jackson.databind.deser.std.StdDeserializer;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableMap;
import java.io.IOException;
import java.util.List;
import java.util.Map;
import java.util.Optional;
import javax.annotation.Nullable;
/**
* JSON deserializer specialized to parse the output of {@code buck.py} into {@link
* BuildFilePythonResult}.
*
* <p>Uses Guava {@link ImmutableMap} and {@link ImmutableList} to reduce memory pressure, along
* with {@link ImmutableMapWithNullValues} to allow {@code null} values in the maps.
*/
final class BuildFilePythonResultDeserializer extends StdDeserializer<BuildFilePythonResult> {
public BuildFilePythonResultDeserializer() {
super(BuildFilePythonResult.class);
}
@Override
public BuildFilePythonResult deserialize(JsonParser jp, DeserializationContext ctxt)
throws IOException, JsonParseException {
if (jp.getCurrentToken() != JsonToken.START_OBJECT) {
throw new JsonParseException(jp, "Missing expected START_OBJECT");
}
ImmutableList<Map<String, Object>> values = ImmutableList.of();
ImmutableList<Map<String, Object>> diagnostics = ImmutableList.of();
Optional<String> profile = Optional.empty();
String fieldName;
while ((fieldName = jp.nextFieldName()) != null) {
switch (fieldName) {
case "values":
values = deserializeObjectList(jp);
break;
case "diagnostics":
diagnostics = deserializeObjectList(jp);
break;
case "profile":
profile = Optional.of(jp.nextTextValue());
break;
default:
throw new JsonParseException(jp, "Unexpected field name: " + fieldName);
}
}
if (jp.getCurrentToken() != JsonToken.END_OBJECT) {
throw new JsonParseException(jp, "Missing expected END_OBJECT");
}
return BuildFilePythonResult.of(values, diagnostics, profile);
}
private static ImmutableList<Map<String, Object>> deserializeObjectList(JsonParser jp)
throws IOException, JsonParseException {
JsonToken token = jp.nextToken();
if (token != JsonToken.START_ARRAY) {
throw new JsonParseException(jp, "Missing expected START_ARRAY, got: " + token);
}
ImmutableList.Builder<Map<String, Object>> result = ImmutableList.builder();
while ((token = jp.nextToken()) == JsonToken.START_OBJECT) {
result.add(deserializeObject(jp));
}
if (token != JsonToken.END_ARRAY) {
throw new JsonParseException(jp, "Missing expected END_ARRAY");
}
return result.build();
}
private static Map<String, Object> deserializeObject(JsonParser jp)
throws IOException, JsonParseException {
ImmutableMapWithNullValues.Builder<String, Object> builder =
ImmutableMapWithNullValues.Builder.insertionOrder();
String fieldName;
while ((fieldName = jp.nextFieldName()) != null) {
builder.put(fieldName, deserializeRecursive(jp, jp.nextToken()));
}
if (jp.getCurrentToken() != JsonToken.END_OBJECT) {
throw new JsonParseException(jp, "Missing expected END_OBJECT");
}
return builder.build();
}
private static List<Object> deserializeList(JsonParser jp)
throws IOException, JsonParseException {
ImmutableList.Builder<Object> builder = ImmutableList.builder();
JsonToken token;
while ((token = jp.nextToken()) != JsonToken.END_ARRAY) {
builder.add(deserializeRecursive(jp, token));
}
if (token != JsonToken.END_ARRAY) {
throw new JsonParseException(jp, "Missing expected END_ARRAY");
}
return builder.build();
}
@Nullable
private static Object deserializeRecursive(JsonParser jp, JsonToken token)
throws IOException, JsonParseException {
switch (token) {
case START_OBJECT:
return deserializeObject(jp);
case START_ARRAY:
return deserializeList(jp);
case VALUE_TRUE:
return true;
case VALUE_FALSE:
return false;
case VALUE_NULL:
return null;
case VALUE_NUMBER_FLOAT:
return jp.getDoubleValue();
case VALUE_NUMBER_INT:
return jp.getLongValue();
case VALUE_STRING:
return jp.getText();
// $CASES-OMITTED$
default:
throw new JsonParseException(jp, "Unexpected token: " + token.toString());
}
}
}