Add support for bytes in Encoders (#998)

* Add support for bytes in Encoders.

* Add tests.

* Fix tests.

* Merge byte[] into add(object) logic.

* Update api.txt

* Fix format

Author: rlazo

encoders/firebase-encoders/api.txt

@@ -29,6 +29,7 @@ package com.google.firebase.encoders {
     method @NonNull public com.google.firebase.encoders.ValueEncoderContext add(double) throws com.google.firebase.encoders.EncodingException;
     method @NonNull public com.google.firebase.encoders.ValueEncoderContext add(int) throws com.google.firebase.encoders.EncodingException;
     method @NonNull public com.google.firebase.encoders.ValueEncoderContext add(boolean) throws com.google.firebase.encoders.EncodingException;
+    method @NonNull public com.google.firebase.encoders.ValueEncoderContext add(@NonNull byte[]) throws com.google.firebase.encoders.EncodingException;
   }
 
 }

encoders/firebase-encoders/src/main/java/com/google/firebase/encoders/ValueEncoderContext.java

@@ -42,4 +42,8 @@ public interface ValueEncoderContext {
   /** Adds {@code value} as a primitive encoded value. */
   @NonNull
   ValueEncoderContext add(boolean value) throws IOException, EncodingException;
+
+  /** Adds {@code value} as a encoded array of bytes. */
+  @NonNull
+  ValueEncoderContext add(@NonNull byte[] bytes) throws IOException, EncodingException;
 }

encoders/firebase-encoders/src/main/java/com/google/firebase/encoders/json/JsonValueObjectEncoderContext.java

@@ -14,6 +14,7 @@
 
 package com.google.firebase.encoders.json;
 
+import android.util.Base64;
 import android.util.JsonWriter;
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
@@ -107,6 +108,18 @@ public JsonValueObjectEncoderContext add(boolean value) throws IOException, Enco
     return this;
   }
 
+  @NonNull
+  @Override
+  public JsonValueObjectEncoderContext add(@Nullable byte[] bytes)
+      throws IOException, EncodingException {
+    if (bytes == null) {
+      jsonWriter.nullValue();
+    } else {
+      jsonWriter.value(Base64.encodeToString(bytes, Base64.NO_WRAP));
+    }
+    return this;
+  }
+
   @NonNull
   JsonValueObjectEncoderContext add(@Nullable Object o) throws IOException, EncodingException {
     if (o == null) {
@@ -115,6 +128,13 @@ JsonValueObjectEncoderContext add(@Nullable Object o) throws IOException, Encodi
     }
     // TODO: Add missing primitive types.
     if (o.getClass().isArray()) {
+      // Byte[] are a special case of arrays, because they are not mapped to an array, but to a
+      // string.
+      if (o.getClass().getComponentType() == byte.class) {
+        byte[] bytes = (byte[]) o;
+        return add(bytes);
+      }
+
       jsonWriter.beginArray();
       if (o.getClass().getComponentType() == int.class) {
         int[] array = (int[]) o;

encoders/firebase-encoders/src/test/java/com/google/firebase/encoders/json/JsonValueObjectEncoderContextTest.java

@@ -27,6 +27,7 @@
 import com.google.firebase.encoders.ValueEncoder;
 import java.io.IOException;
 import java.io.Writer;
+import java.nio.charset.Charset;
 import java.util.Calendar;
 import java.util.TimeZone;
 import org.junit.Assert;
@@ -145,6 +146,22 @@ public void testEncodingCollection() throws IOException, EncodingException {
                 "[{\"Name\":\"innerClass\"},{\"Name\":\"innerClass\"}]"));
   }
 
+  @Test
+  public void testEncodingBytes() throws IOException, EncodingException {
+    ObjectEncoder<DummyClass> objectEncoder =
+        (o, ctx) -> {
+          ctx.add("Bytes", "My {custom} value.".getBytes(Charset.forName("UTF-8")));
+        };
+
+    String result =
+        new JsonDataEncoderBuilder()
+            .registerEncoder(DummyClass.class, objectEncoder)
+            .build()
+            .encode(DummyClass.INSTANCE);
+
+    assertThat(result).isEqualTo(String.format("{\"Bytes\":%s}", "\"TXkge2N1c3RvbX0gdmFsdWUu\""));
+  }
+
   @Test
   public void testEncodingCollectionBoxedPrimitives() throws IOException, EncodingException {
     ObjectEncoder<DummyClass> objectEncoder =