io.dapr.internal.opencensus.BinaryFormatImpl Maven / Gradle / Ivy
/*
* Copyright 2021 The Dapr Authors
* 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 io.dapr.internal.opencensus;
import static com.google.common.base.Preconditions.checkNotNull;
/**
* Code originally from https://github.com/census-instrumentation/opencensus-java/blob/
* 446e9bde9b1f6c0317e3f310644997e5d6d5eab2/impl_core/src/main/java/io/opencensus/
* implcore/trace/propagation/BinaryFormatImpl.java
*/
final class BinaryFormatImpl {
private static final byte VERSION_ID = 0;
private static final int VERSION_ID_OFFSET = 0;
// The version_id/field_id size in bytes.
private static final byte ID_SIZE = 1;
private static final byte TRACE_ID_FIELD_ID = 0;
// TODO: clarify if offsets are correct here. While the specification suggests you should stop
// parsing when you hit an unknown field, it does not suggest that fields must be declared in
// ID order. Rather it only groups by data type order, in this case Trace Context
// https://github.com/census-instrumentation/opencensus-specs/blob/master/encodings/BinaryEncoding
// .md#deserialization-rules
private static final int TRACE_ID_FIELD_ID_OFFSET = VERSION_ID_OFFSET + ID_SIZE;
private static final int TRACE_ID_OFFSET = TRACE_ID_FIELD_ID_OFFSET + ID_SIZE;
private static final byte SPAN_ID_FIELD_ID = 1;
private static final int SPAN_ID_FIELD_ID_OFFSET = TRACE_ID_OFFSET + TraceId.SIZE;
private static final int SPAN_ID_OFFSET = SPAN_ID_FIELD_ID_OFFSET + ID_SIZE;
private static final byte TRACE_OPTION_FIELD_ID = 2;
private static final int TRACE_OPTION_FIELD_ID_OFFSET = SPAN_ID_OFFSET + SpanId.SIZE;
private static final int TRACE_OPTIONS_OFFSET = TRACE_OPTION_FIELD_ID_OFFSET + ID_SIZE;
/**
* Version, Trace and Span IDs are required fields.
*/
private static final int REQUIRED_FORMAT_LENGTH = 3 * ID_SIZE + TraceId.SIZE + SpanId.SIZE;
private static final int ALL_FORMAT_LENGTH = REQUIRED_FORMAT_LENGTH + ID_SIZE + TraceOptions.SIZE;
/**
* Generates the byte array for a span context.
* @param spanContext OpenCensus' span context.
* @return byte array for span context.
*/
byte[] toByteArray(SpanContext spanContext) {
checkNotNull(spanContext, "spanContext");
byte[] bytes = new byte[ALL_FORMAT_LENGTH];
bytes[VERSION_ID_OFFSET] = VERSION_ID;
bytes[TRACE_ID_FIELD_ID_OFFSET] = TRACE_ID_FIELD_ID;
spanContext.getTraceId().copyBytesTo(bytes, TRACE_ID_OFFSET);
bytes[SPAN_ID_FIELD_ID_OFFSET] = SPAN_ID_FIELD_ID;
spanContext.getSpanId().copyBytesTo(bytes, SPAN_ID_OFFSET);
bytes[TRACE_OPTION_FIELD_ID_OFFSET] = TRACE_OPTION_FIELD_ID;
spanContext.getTraceOptions().copyBytesTo(bytes, TRACE_OPTIONS_OFFSET);
return bytes;
}
}