Implement JSON for boxed oneofs.

wire-library/wire-gson-support/src/main/java/com/squareup/wire/MessageTypeAdapter.kt

@@ -18,7 +18,7 @@ package com.squareup.wire
 import com.google.gson.TypeAdapter
 import com.google.gson.stream.JsonReader
 import com.google.gson.stream.JsonWriter
-import com.squareup.wire.internal.FieldBinding
+import com.squareup.wire.internal.FieldOrOneOfBinding
 import com.squareup.wire.internal.RuntimeMessageAdapter
 import java.io.IOException
 
@@ -79,6 +79,6 @@ internal class MessageTypeAdapter<M : Message<M, B>, B : Message.Builder<M, B>>(
 
   data class JsonField<M : Message<M, B>, B : Message.Builder<M, B>>(
     val adapter: TypeAdapter<Any?>,
-    val fieldBinding: FieldBinding<M, B>
+    val fieldBinding: FieldOrOneOfBinding<M, B>
   )
 }

wire-library/wire-kotlin-generator/src/main/java/com/squareup/wire/kotlin/KotlinGenerator.kt

@@ -68,6 +68,7 @@ import com.squareup.wire.WireEnum
 import com.squareup.wire.WireEnumConstant
 import com.squareup.wire.WireField
 import com.squareup.wire.WireRpc
+import com.squareup.wire.internal.boxedOneOfKeysFieldName
 import com.squareup.wire.internal.camelCase
 import com.squareup.wire.schema.EnclosingType
 import com.squareup.wire.schema.EnumConstant
@@ -96,12 +97,12 @@ import com.squareup.wire.schema.internal.eligibleAsAnnotationMember
 import com.squareup.wire.schema.internal.javaPackage
 import com.squareup.wire.schema.internal.optionValueToInt
 import com.squareup.wire.schema.internal.optionValueToLong
+import java.util.Locale
 import kotlinx.coroutines.Deferred
 import kotlinx.coroutines.channels.ReceiveChannel
 import kotlinx.coroutines.channels.SendChannel
 import okio.ByteString
 import okio.ByteString.Companion.encode
-import java.util.Locale
 
 class KotlinGenerator private constructor(
   val schema: Schema,
@@ -403,12 +404,15 @@ class KotlinGenerator private constructor(
               }
             }
             message.boxOneOfs().forEach { oneOf ->
-              newName(oneOf.name, oneOf)
-              newName(oneOf.name + "Keys",oneOf.name + "Keys")
+              val fieldName = newName(oneOf.name, oneOf)
+              val keysFieldName = boxedOneOfKeysFieldName(fieldName)
+              check(newName(keysFieldName) == keysFieldName) {
+                "unexpected name collision for keys set of boxed one of, ${oneOf.name}"
+              }
               newName(oneOf.name.capitalize(), oneOf.name.capitalize())
-               oneOf.fields.forEach { field ->
-                 newName(oneOf.name + field.name.capitalize(), oneOf.name + field.name.capitalize())
-               }
+              oneOf.fields.forEach { field ->
+                newName(oneOf.name + field.name.capitalize(), oneOf.name + field.name.capitalize())
+              }
             }
           }
         }
@@ -1406,7 +1410,7 @@ class KotlinGenerator private constructor(
           val choiceKey = nameAllocator.newName("choiceKey")
           for (boxOneOf in message.boxOneOfs()) {
             val fieldName = nameAllocator[boxOneOf]
-            val choiceKeys = nameAllocator[boxOneOf.name + "Keys"]
+            val choiceKeys = boxedOneOfKeysFieldName(fieldName)
             beginControlFlow("for (%L in %L)", choiceKey, choiceKeys)
             beginControlFlow("if (%L == %L.tag)", tag, choiceKey)
             addStatement("%L = %L.decode(reader)", fieldName, choiceKey)
@@ -1995,11 +1999,14 @@ class KotlinGenerator private constructor(
       companionBuilder.addProperty(oneOfKey)
     }
 
+    val fieldName = nameAllocator[oneOf]
+    val keysFieldName = boxedOneOfKeysFieldName(fieldName)
     val allKeys = PropertySpec
       .builder(
-        nameAllocator[oneOf.name + "Keys"],
+        keysFieldName,
         Set::class.asClassName().parameterizedBy(boxClassName.parameterizedBy(STAR))
       )
+      .addAnnotation(JvmStatic::class.java)
       .initializer(
         CodeBlock.of(
           """setOf(${keyFieldNames.map { "%L" }.joinToString(", ")})""",

wire-library/wire-runtime/src/commonMain/kotlin/com/squareup/wire/internal/Internal.kt

@@ -205,3 +205,8 @@ fun sanitize(value: String): String {
 fun sanitize(values: List<String>): String {
   return values.map(::sanitize).joinToString(prefix = "[", postfix = "]")
 }
+
+/** Maps [fieldName] to the companion object field of type `Set` containing the eligible keys.  */
+fun boxedOneOfKeysFieldName(fieldName: String): String {
+  return "${fieldName}Keys"
+}

wire-library/wire-runtime/src/jvmMain/kotlin/com/squareup/wire/internal/FieldBinding.kt

@@ -17,6 +17,7 @@ package com.squareup.wire.internal
 
 import com.squareup.wire.Message
 import com.squareup.wire.ProtoAdapter
+import com.squareup.wire.Syntax
 import com.squareup.wire.WireField
 import java.lang.reflect.Field
 import java.lang.reflect.Method
@@ -29,16 +30,16 @@ class FieldBinding<M : Message<M, B>, B : Message.Builder<M, B>> internal constr
   wireField: WireField,
   private val messageField: Field,
   builderType: Class<B>
-) {
-  val label: WireField.Label = wireField.label
-  val name: String = messageField.name
-  val declaredName: String =
+) : FieldOrOneOfBinding<M, B> {
+  override val label: WireField.Label = wireField.label
+  override val name: String = messageField.name
+  override val wireFieldJsonName: String = wireField.jsonName
+  override val declaredName: String =
       if (wireField.declaredName.isEmpty()) messageField.name else wireField.declaredName
-  val jsonName: String = if (wireField.jsonName.isEmpty()) declaredName else wireField.jsonName
-  val tag: Int = wireField.tag
+  override val tag: Int = wireField.tag
   private val keyAdapterString = wireField.keyAdapter
   private val adapterString = wireField.adapter
-  val redacted: Boolean = wireField.redacted
+  override val redacted: Boolean = wireField.redacted
   private val builderField = getBuilderField(builderType, name)
   private val builderMethod = getBuilderMethod(builderType, name, messageField.type)
 
@@ -47,7 +48,7 @@ class FieldBinding<M : Message<M, B>, B : Message.Builder<M, B>> internal constr
   private var keyAdapter: ProtoAdapter<*>? = null
   private var adapter: ProtoAdapter<Any>? = null
 
-  val isMap: Boolean
+  override val isMap: Boolean
     get() = keyAdapterString.isNotEmpty()
 
   private fun getBuilderField(builderType: Class<*>, name: String): Field {
@@ -66,15 +67,15 @@ class FieldBinding<M : Message<M, B>, B : Message.Builder<M, B>> internal constr
     }
   }
 
-  fun singleAdapter(): ProtoAdapter<*> {
+  override fun singleAdapter(): ProtoAdapter<*> {
     return singleAdapter ?: ProtoAdapter.get(adapterString).also { singleAdapter = it }
   }
 
-  fun keyAdapter(): ProtoAdapter<*> {
+  override fun keyAdapter(): ProtoAdapter<*> {
     return keyAdapter ?: ProtoAdapter.get(keyAdapterString).also { keyAdapter = it }
   }
 
-  internal fun adapter(): ProtoAdapter<Any> {
+  override fun adapter(): ProtoAdapter<Any> {
     val result = adapter
     if (result != null) return result
     if (isMap) {
@@ -88,7 +89,7 @@ class FieldBinding<M : Message<M, B>, B : Message.Builder<M, B>> internal constr
   }
 
   /** Accept a single value, independent of whether this value is single or repeated. */
-  internal fun value(builder: B, value: Any) {
+  override fun value(builder: B, value: Any) {
     when {
       label.isRepeated -> {
         when (val list = getFromBuilder(builder)) {
@@ -123,7 +124,7 @@ class FieldBinding<M : Message<M, B>, B : Message.Builder<M, B>> internal constr
   }
 
   /** Assign a single value for required/optional fields, or a list for repeated/packed fields. */
-  fun set(builder: B, value: Any?) {
+  override fun set(builder: B, value: Any?) {
     if (label.isOneOf) {
       // In order to maintain the 'oneof' invariant, call the builder setter method rather
       // than setting the builder field directly.
@@ -133,7 +134,18 @@ class FieldBinding<M : Message<M, B>, B : Message.Builder<M, B>> internal constr
     }
   }
 
-  operator fun get(message: M): Any? = messageField.get(message)
+  override operator fun get(message: M): Any? = messageField.get(message)
 
-  internal fun getFromBuilder(builder: B): Any? = builderField.get(builder)
+  override fun getFromBuilder(builder: B): Any? = builderField.get(builder)
+
+  override fun omitFromJson(syntax: Syntax, value: Any?): Boolean {
+    return omitIdentity(syntax) && value == adapter().identity
+  }
+
+  private fun omitIdentity(syntax: Syntax): Boolean {
+    if (label == WireField.Label.OMIT_IDENTITY) return true
+    if (label.isRepeated && syntax == Syntax.PROTO_3) return true
+    if (isMap && syntax == Syntax.PROTO_3) return true
+    return false
+  }
 }

wire-library/wire-runtime/src/jvmMain/kotlin/com/squareup/wire/internal/FieldOrOneOfBinding.kt

@@ -0,0 +1,64 @@
+/*
+ * Copyright 2021 Square 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.squareup.wire.internal
+
+import com.squareup.wire.Message
+import com.squareup.wire.ProtoAdapter
+import com.squareup.wire.Syntax
+import com.squareup.wire.WireField
+
+interface FieldOrOneOfBinding<M : Message<M, B>, B : Message.Builder<M, B>> {
+  val tag: Int
+
+  val label: WireField.Label
+
+  val redacted: Boolean
+
+  val isMap: Boolean
+
+  /**
+   * The name of the field in generated code. If the declared name is a keyword like `fun`, this
+   * will be a transformed name like `fun_`.
+   */
+  val name: String
+
+  /**
+   * The name of the field as declared in the `.proto` file.
+   */
+  val declaredName: String
+
+  /**
+   * The JSON name as determined at code-generation name. This is usually camelCase even if the
+   * field is declared in snake_case.
+   */
+  val wireFieldJsonName: String
+
+  fun keyAdapter(): ProtoAdapter<*>
+
+  fun adapter(): ProtoAdapter<Any>
+
+  fun value(builder: B, value: Any)
+
+  fun set(builder: B, value: Any?)
+
+  operator fun get(message: M): Any?
+
+  fun getFromBuilder(builder: B): Any?
+
+  fun singleAdapter(): ProtoAdapter<*>
+
+  fun omitFromJson(syntax: Syntax, value: Any?): Boolean
+}

wire-library/wire-runtime/src/jvmMain/kotlin/com/squareup/wire/internal/JsonIntegration.kt

@@ -56,7 +56,7 @@ abstract class JsonIntegration<F, A> {
   fun <M : Message<M, B>, B : Message.Builder<M, B>> jsonAdapter(
     framework: F,
     syntax: Syntax,
-    field: FieldBinding<M, B>
+    field: FieldOrOneOfBinding<M, B>
   ): A {
     if (field.singleAdapter().isStruct) {
       return structAdapter(framework)

wire-library/wire-runtime/src/jvmMain/kotlin/com/squareup/wire/internal/OneOfBinding.kt

@@ -0,0 +1,86 @@
+/*
+ * Copyright 2021 Square 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.squareup.wire.internal
+
+import com.squareup.wire.Message
+import com.squareup.wire.OneOf
+import com.squareup.wire.ProtoAdapter
+import com.squareup.wire.Syntax
+import com.squareup.wire.WireField
+import java.lang.reflect.Field
+
+internal class OneOfBinding<M : Message<M, B>, B : Message.Builder<M, B>> internal constructor(
+  private val messageField: Field,
+  builderType: Class<B>,
+  private val key: OneOf.Key<*>
+) : FieldOrOneOfBinding<M, B> {
+  private val builderField: Field = builderType.getDeclaredField(messageField.name)
+
+  override val tag: Int
+    get() = key.tag
+
+  override val label: WireField.Label
+    get() = WireField.Label.OPTIONAL
+
+  override val redacted: Boolean
+    get() = key.redacted
+
+  override val wireFieldJsonName: String
+    get() = key.jsonName
+
+  override val name: String
+    get() = key.declaredName
+
+  override val declaredName: String
+    get() = key.declaredName
+
+  override val isMap: Boolean
+    get() = false
+
+  override fun keyAdapter(): ProtoAdapter<*> {
+    error("not a map")
+  }
+
+  override fun adapter(): ProtoAdapter<Any> {
+    return key.adapter as ProtoAdapter<Any>
+  }
+
+  override fun value(builder: B, value: Any) {
+    set(builder, value)
+  }
+
+  override fun set(builder: B, value: Any?) {
+    builderField.set(builder, OneOf(key as OneOf.Key<Any>, value!!))
+  }
+
+  override fun get(message: M): Any? {
+    val oneOfOrNull = messageField.get(message) as OneOf<*, *>?
+    return oneOfOrNull?.getOrNull(key)
+  }
+
+  override fun getFromBuilder(builder: B): Any? {
+    val oneOfOrNull = builderField.get(builder) as OneOf<*, *>?
+    return oneOfOrNull?.getOrNull(key)
+  }
+
+  override fun singleAdapter(): ProtoAdapter<*> {
+    return adapter()
+  }
+
+  override fun omitFromJson(syntax: Syntax, value: Any?): Boolean {
+    return value == null
+  }
+}