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lucaspimentellucaspimentel
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initial attempt to add W3CBaggageHttpCodec
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3 files changed

+201
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3 files changed

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‎dd-trace-api/src/main/java/datadog/trace/api/TracePropagationStyle.java‎

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@@ -21,6 +21,9 @@ public enum TracePropagationStyle {
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// W3C trace context propagation style
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// https://www.w3.org/TR/trace-context-1/
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TRACECONTEXT,
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// W3C baggage propagation style
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// https://www.w3.org/TR/baggage/
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BAGGAGE,
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// None does not extract or inject
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NONE;
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‎dd-trace-core/src/main/java/datadog/trace/core/propagation/HttpCodec.java‎

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@@ -125,6 +125,8 @@ private static Map<TracePropagationStyle, Injector> createInjectors(
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case TRACECONTEXT:
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result.put(style, W3CHttpCodec.newInjector(reverseBaggageMapping));
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break;
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case BAGGAGE:
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result.put(style, W3CBaggageHttpCodec.newInjector(reverseBaggageMapping));
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default:
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log.debug("No implementation found to inject propagation style: {}", style);
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break;
@@ -159,6 +161,9 @@ public static Extractor createExtractor(
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case TRACECONTEXT:
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extractors.add(W3CHttpCodec.newExtractor(config, traceConfigSupplier));
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break;
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case BAGGAGE:
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extractors.add(W3CBaggageHttpCodec.newExtractor(config, traceConfigSupplier));
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break;
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default:
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log.debug("No implementation found to extract propagation style: {}", style);
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break;

‎dd-trace-core/src/main/java/datadog/trace/core/propagation/W3CBaggageHttpCodec.java‎

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@@ -0,0 +1,193 @@
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package datadog.trace.core.propagation;
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import static datadog.trace.api.TracePropagationStyle.TRACECONTEXT;
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import static datadog.trace.api.sampling.PrioritySampling.SAMPLER_DROP;
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import static datadog.trace.api.sampling.PrioritySampling.SAMPLER_KEEP;
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import static datadog.trace.core.propagation.HttpCodec.firstHeaderValue;
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import static datadog.trace.core.propagation.PropagationTags.HeaderType.W3C;
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import static java.util.concurrent.TimeUnit.MILLISECONDS;
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import static java.util.concurrent.TimeUnit.NANOSECONDS;
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import datadog.trace.api.Config;
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import datadog.trace.api.DD128bTraceId;
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import datadog.trace.api.DDSpanId;
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import datadog.trace.api.DDTags;
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import datadog.trace.api.DDTraceId;
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import datadog.trace.api.TraceConfig;
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import datadog.trace.api.TracePropagationStyle;
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import datadog.trace.api.internal.util.LongStringUtils;
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import datadog.trace.api.sampling.PrioritySampling;
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import datadog.trace.api.sampling.SamplingMechanism;
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import datadog.trace.bootstrap.instrumentation.api.AgentPropagation;
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import datadog.trace.bootstrap.instrumentation.api.TagContext;
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import datadog.trace.core.DDSpanContext;
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import java.util.Map;
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import java.util.TreeMap;
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import java.util.function.Supplier;
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import java.net.URLEncoder;
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import java.nio.charset.StandardCharsets;
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import org.slf4j.Logger;
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import org.slf4j.LoggerFactory;
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/** A codec designed for HTTP transport via headers using W3C "baggage" header */
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class W3CBaggageHttpCodec {
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private static final Logger log = LoggerFactory.getLogger(W3CHttpCodec.class);
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static final String BAGGAGE_KEY = "baggage";
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private W3CBaggageHttpCodec() {
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// This class should not be created. This also makes code coverage checks happy.
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}
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public static HttpCodec.Injector newInjector(Map<String, String> invertedBaggageMapping) {
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return new Injector(invertedBaggageMapping);
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}
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private static class Injector implements HttpCodec.Injector {
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private final Map<String, String> invertedBaggageMapping;
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public Injector(Map<String, String> invertedBaggageMapping) {
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assert invertedBaggageMapping != null;
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this.invertedBaggageMapping = invertedBaggageMapping;
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}
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@Override
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public <C> void inject(
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final DDSpanContext context, final C carrier, final AgentPropagation.Setter<C> setter) {
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StringBuilder baggageHeader = new StringBuilder();
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for (final Map.Entry<String, String> entry : context.baggageItems()) {
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if (baggageHeader.length() > 0) {
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baggageHeader.append(",");
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}
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String header = invertedBaggageMapping.get(entry.getKey());
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header = header != null ? header : entry.getKey();
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String value = HttpCodec.encodeBaggage(entry.getValue());
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baggageHeader.append(header).append("=").append(value);
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}
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setter.set(carrier, BAGGAGE_KEY, baggageHeader.toString());
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}
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}
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public static HttpCodec.Extractor newExtractor(
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Config config, Supplier<TraceConfig> traceConfigSupplier) {
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return new TagContextExtractor(traceConfigSupplier, () -> new W3CBaggageContextInterpreter(config));
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}
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private static class W3CBaggageContextInterpreter extends ContextInterpreter {
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private W3CBaggageContextInterpreter(Config config) {
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super(config);
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}
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@Override
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public TracePropagationStyle style() {
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return BAGGAGE;
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}
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@Override
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public boolean accept(String key, String value) {
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if (null == key || key.isEmpty()) {
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return true;
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}
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if (LOG_EXTRACT_HEADER_NAMES) {
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log.debug("Header: {}", key);
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}
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if (first == 'b' && BAGGAGE_KEY.equalsIgnoreCase(key)) {
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try {
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if (baggage.isEmpty()) {
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baggage = new TreeMap<>();
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}
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// Split by comma
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for (String entry : header.split(",")) {
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// Split into key=value
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String[] keyValue = entry.split("=", 2);
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if (keyValue.length == 2) {
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baggage.put(
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HttpCodec.decode(keyValue[0].trim()),
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HttpCodec.decode(keyValue[1].trim())
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);
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}
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}
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} catch (RuntimeException e) {
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invalidateContext();
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log.debug("Exception when extracting baggage", e);
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return false;
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}
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}
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return true;
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}
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private long extractEndToEndStartTime(String value) {
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try {
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return MILLISECONDS.toNanos(Long.parseLong(value));
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} catch (RuntimeException e) {
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log.debug("Ignoring invalid end-to-end start time {}", value, e);
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return 0;
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}
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}
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private boolean storeTraceParent(String value) {
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String trimmed = trim(value);
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if (traceparentHeader != null) {
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// We should not accept multiple traceparent headers
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if (log.isDebugEnabled()) {
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log.debug(
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"Multiple traceparent headers. Had '{}' and got '{}'", traceparentHeader, trimmed);
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}
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onlyTagContext();
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} else {
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traceparentHeader = trimmed;
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}
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return true;
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}
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private boolean storeTraceState(String value) {
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String trimmed = trim(value);
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if (!trimmed.isEmpty()) {
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// Yes, this is not efficient for multiple headers, but that is hopefully not common
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tracestateHeader = tracestateHeader == null ? trimmed : tracestateHeader + "," + trimmed;
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}
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return true;
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}
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private static String trim(String input) {
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if (input == null) {
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return "";
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}
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final int last = input.length() - 1;
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if (last == 0) {
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return input;
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}
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int start;
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for (start = 0; start <= last; start++) {
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char c = input.charAt(start);
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if (c != '\t' && c != ' ') {
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break;
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}
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}
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int end;
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for (end = last; end > start; end--) {
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char c = input.charAt(end);
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if (c != '\t' && c != ' ') {
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break;
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}
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}
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if (start == 0 && end == last) {
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return input;
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} else {
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return input.substring(start, end + 1);
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}
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}
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}
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}

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