Serializes CensusContextImpl as a Protocol Buffer.

Author: sebright2

BUILD

@@ -26,8 +26,10 @@ java_library(
     srcs = glob(["core_native/java/com/google/census/*.java"]),
     deps = [
         ":census-core",
+        "//proto:census_context-proto-java",
         "@guava//jar",
         "@jsr305//jar",
+        "@protobuf//jar",
     ],
 )
 

WORKSPACE

@@ -24,7 +24,18 @@ maven_jar(
     artifact = "junit:junit:4.11",
 )
 
+maven_jar(
+    name = "protobuf",
+    artifact = "com.google.protobuf:protobuf-java:3.0.0",
+)
+
 maven_jar(
     name = "truth",
     artifact = "com.google.truth:truth:0.28",
-)
+)
+
+git_repository(
+    name = "io_bazel",
+    remote = "https://github.com/bazelbuild/bazel",
+    tag = "0.3.1",
+)

core/java/com/google/census/Census.java

@@ -41,7 +41,11 @@ public static CensusContext getCurrent() {
     return CONTEXT_FACTORY.getCurrent();
   }
 
-  /** Creates a {@link CensusContext} from the given on-the-wire encoded representation. */
+  /**
+   * Creates a {@link CensusContext} from the given on-the-wire encoded representation. Should be
+   * the inverse of {@link CensusContext#serialize()}. The serialized representation should be
+   * based on the {@link CensusContext} protobuf representation.
+   */
   @Nullable
   public static CensusContext deserialize(ByteBuffer buffer) {
     return CONTEXT_FACTORY.deserialize(buffer);

core/java/com/google/census/CensusContext.java

@@ -48,6 +48,8 @@ public final CensusContext with(
 
   /**
    * Serializes the {@link CensusContext} into the on-the-wire representation.
+   * The inverse of {@link CensusContextFactory#deserialize()} and should be based on the
+   * {@link CensusContext} protobuf representation.
    *
    * @return serialized bytes.
    */

core/java/com/google/census/CensusContextFactory.java

@@ -14,14 +14,16 @@
 package com.google.census;
 
 import java.nio.ByteBuffer;
-
 import javax.annotation.Nullable;
 
 /**
  * Factory class for {@link CensusContext}.
  */
 public abstract class CensusContextFactory {
-  /** Creates a new {@link CensusContext} built from the given on-the-wire encoded representation.
+  /**
+   * Creates a {@link CensusContext} from the given on-the-wire encoded representation. Should be
+   * the inverse of {@link CensusContext#serialize()}. The serialized representation should be
+   * based on the {@link CensusContext} protobuf representation.
    *
    * @param buffer on-the-wire representation of a {@link CensusContext}
    * @return a {@link CensusContext} deserialized from {@code buffer}

core/javatests/com/google/census/CensusContextFactoryTest.java

@@ -15,14 +15,11 @@
 
 import static com.google.common.truth.Truth.assertThat;
 
-import static java.nio.charset.StandardCharsets.UTF_8;
-
+import java.nio.ByteBuffer;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.junit.runners.JUnit4;
 
-import java.nio.ByteBuffer;
-
 /**
  * Tests for {@link CensusContextFactory}.
  */
@@ -33,12 +30,6 @@ public void testDeserializeEmpty() {
     assertThat(Census.deserialize(ByteBuffer.wrap(new byte[0]))).isEqualTo(Census.getDefault());
   }
 
-  @Test
-  public void testDeserializeBadData() {
-    assertThat(Census.deserialize(ByteBuffer.wrap("\2as\3df\2".getBytes(UTF_8))))
-        .isNull();
-  }
-
   @Test
   public void testGetCurrent() {
     assertThat(Census.getCurrent()).isEqualTo(Census.getDefault());

core/javatests/com/google/census/CensusContextTest.java

@@ -147,7 +147,7 @@ public void testMultipleThreadsWithContext() throws Exception {
   // Tests for Object overrides.
   @Test
   public void testEquals() {
-    assertThat(DEFAULT).isEqualTo(DEFAULT);
+    assertThat(DEFAULT).isEqualTo(DEFAULT.builder().build());
     assertThat(DEFAULT.with(K1, V1)).isEqualTo(DEFAULT.with(K1, V1));
     assertThat(DEFAULT.with(K1, V1, K2, V2)).isEqualTo(DEFAULT.with(K1, V1, K2, V2));
     assertThat(DEFAULT.with(K1, V1, K2, V2)).isEqualTo(DEFAULT.with(K2, V2, K1, V1));

core_native/java/com/google/census/CensusContextFactoryImpl.java

@@ -15,30 +15,27 @@
 
 import java.nio.ByteBuffer;
 import java.util.HashMap;
-
 import javax.annotation.Nullable;
 
 /** Native Implementation of {@link CensusContextFactory} */
 final class CensusContextFactoryImpl extends CensusContextFactory {
   static final CensusContextImpl DEFAULT = new CensusContextImpl(new HashMap<String, String>(0));
 
   /**
-   * The serialized tags are of the form:
-   * {@code (<tag prefix> + 'key' + <tag delim> + 'value')}
+   * Deserializes a {@link CensusContextImpl} from a serialized {@link CensusContextProto}. The
+   * encoded tags are of the form: (<tag prefix> + 'key' + <tag delim> + 'value')*
    */
   @Override
   @Nullable
   public CensusContextImpl deserialize(ByteBuffer buffer) {
     return CensusSerializer.deserialize(buffer);
   }
 
-  /** Returns the current thread-local {@link CensusContext}. */
   @Override
   public CensusContext getCurrent() {
     return CensusCurrentContext.get();
   }
 
-  /** Returns the default {@link CensusContext}. */
   @Override
   public CensusContext getDefault() {
     return DEFAULT;

core_native/java/com/google/census/CensusContextImpl.java

@@ -34,6 +34,10 @@ public CensusContextImpl record(MetricMap stats) {
     return this;
   }
 
+  /**
+   * Serializes a {@link CensusContextImpl} into {@link CensusContextProto} serialized format. The
+   * encoded tags are of the form: (<tag prefix> + 'key' + <tag delim> + 'value')*
+   */
   @Override
   public ByteBuffer serialize() {
     return CensusSerializer.serialize(this);

core_native/java/com/google/census/CensusSerializer.java

@@ -13,20 +13,22 @@
 
 package com.google.census;
 
-import static java.nio.charset.StandardCharsets.UTF_8;
+import com.google.census.proto.CensusContextProto;
+import com.google.protobuf.InvalidProtocolBufferException;
 
 import java.nio.ByteBuffer;
 import java.util.HashMap;
 import java.util.Map.Entry;
-
 import javax.annotation.Nullable;
 
 /** Native implementation {@link CensusContext} serialization. */
 final class CensusSerializer {
   private static final char TAG_PREFIX = '\2';
   private static final char TAG_DELIM = '\3';
 
-  // The serialized tags are of the form: (<tag prefix> + 'key' + <tag delim> + 'value')*
+
+  // Serializes a CensusContext by transforming it into a CensusContextProto. The
+  // encoded tags are of the form: (<tag prefix> + 'key' + <tag delim> + 'value')*
   static ByteBuffer serialize(CensusContextImpl context) {
     StringBuilder builder = new StringBuilder();
     for (Entry<String, String> tag : context.tags.entrySet()) {
@@ -36,27 +38,58 @@ static ByteBuffer serialize(CensusContextImpl context) {
           .append(TAG_DELIM)
           .append(tag.getValue());
     }
-    return ByteBuffer.wrap(builder.toString().getBytes(UTF_8));
+    return ByteBuffer.wrap(CensusContextProto.CensusContext.
+        newBuilder().setTags(builder.toString()).build().toByteArray());
   }
 
-  // The serialized tags are of the form: (<tag prefix> + 'key' + <tag delim> + 'value')*
+  // Deserializes based on an serialized CensusContextProto. The encoded tags are of the form:
+  // (<tag prefix> + 'key' + <tag delim> + 'value')*
   @Nullable
   static CensusContextImpl deserialize(ByteBuffer buffer) {
-    String input = new String(buffer.array(), UTF_8);
-    HashMap<String, String> tags = new HashMap<>();
-    if (!input.matches("(\2[^\2\3]*\3[^\2\3]*)*")) {
+    try {
+      CensusContextProto.CensusContext context =
+          CensusContextProto.CensusContext.parser().parseFrom(buffer.array());
+      return new CensusContextImpl(fromString(context.getTags()));
+    } catch (IllegalArgumentException | InvalidProtocolBufferException e) {
       return null;
     }
-    if (!input.isEmpty()) {
-      int keyIndex = 0;
-      do {
-        int valIndex = input.indexOf(TAG_DELIM, keyIndex + 1);
-        String key = input.substring(keyIndex + 1, valIndex);
-        keyIndex = input.indexOf(TAG_PREFIX, valIndex + 1);
-        String val = input.substring(valIndex + 1, keyIndex == -1 ? input.length() : keyIndex);
-        tags.put(key, val);
-      } while (keyIndex != -1);
+  }
+
+  private static HashMap<String, String> fromString(String encoded) {
+    HashMap<String, String> tags = new HashMap<>();
+    int length = encoded.length();
+    int index = 0;
+    while (index != length) {
+      int valIndex = endOfKey(encoded, index);
+      String key = encoded.substring(index + 1, valIndex);
+      index = endOfValue(encoded, valIndex);
+      String val = encoded.substring(valIndex + 1, index);
+      tags.put(key, val);
+    }
+    return tags;
+  }
+
+  private static int endOfKey(String encoded, int index) {
+    int valIndex = encoded.indexOf(TAG_DELIM, index);
+    if (valIndex == -1) {
+      throw new IllegalArgumentException("Missing tag delimiter.");
+    }
+    int keyIndex = encoded.lastIndexOf(TAG_PREFIX, valIndex);
+    if (keyIndex != index) {
+      throw new IllegalArgumentException("Missing tag prefix.");
+    }
+    return valIndex;
+  }
+
+  private static int endOfValue(String encoded, int index) {
+    int keyIndex = encoded.indexOf(TAG_PREFIX, index);
+    if (keyIndex == -1) {
+      keyIndex = encoded.length();
+    }
+    int valIndex = encoded.lastIndexOf(TAG_DELIM, keyIndex);
+    if (valIndex != index) {
+      throw new IllegalArgumentException("Missing tag delimiter.");
     }
-    return new CensusContextImpl(tags);
+    return keyIndex;
   }
 }