Get rid of hand-written Struct, Value, and ListValue. (apple#366)

Author: allevato

Makefile

@@ -140,6 +140,7 @@ LIBRARY_PROTOS= \
 	Protos/google/protobuf/empty.proto \
 	Protos/google/protobuf/field_mask.proto \
 	Protos/google/protobuf/source_context.proto \
+	Protos/google/protobuf/struct.proto \
 	Protos/google/protobuf/timestamp.proto \
 	Protos/google/protobuf/type.proto \
 	Protos/google/protobuf/wrappers.proto

Sources/SwiftProtobuf/CustomJSONCodable.swift

@@ -12,10 +12,25 @@
 ///
 // -----------------------------------------------------------------------------
 
-import Foundation
-
 /// Allows WKTs to provide their custom JSON encodings.
 internal protocol _CustomJSONCodable {
-    func encodedJSONString() throws -> String
-    mutating func decodeJSON(from: inout JSONDecoder) throws
+  func encodedJSONString() throws -> String
+  mutating func decodeJSON(from: inout JSONDecoder) throws
+
+  /// Called when the JSON `null` literal is encountered in a position where
+  /// a message of the conforming type is expected. The message type can then
+  /// handle the `null` value differently, if needed; for example,
+  /// `Google_Protobuf_Value` returns a special instance whose `kind` is set to
+  /// `.nullValue(.nullValue)`.
+  ///
+  /// The default behavior is to return `nil`, which indicates that `null`
+  /// should be treated as the absence of a message.
+  static func decodedFromJSONNull() throws -> Self?
+}
+
+extension _CustomJSONCodable {
+  internal static func decodedFromJSONNull() -> Self? {
+    // Return nil by default. Concrete types can provide custom logic.
+    return nil
+  }
 }

Sources/SwiftProtobuf/Google_Protobuf_ListValue+Extensions.swift

@@ -0,0 +1,74 @@
+// Sources/SwiftProtobuf/Google_Protobuf_ListValue+Extensions.swift - ListValue extensions
+//
+// Copyright (c) 2014 - 2017 Apple Inc. and the project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See LICENSE.txt for license information:
+// https://github.com/apple/swift-protobuf/blob/master/LICENSE.txt
+//
+// -----------------------------------------------------------------------------
+///
+/// ListValue is a well-known message type that can be used to parse or encode
+/// arbitrary JSON arrays without a predefined schema.
+///
+// -----------------------------------------------------------------------------
+
+extension Google_Protobuf_ListValue: ExpressibleByArrayLiteral {
+  // TODO: Give this a direct array interface by proxying the interesting
+  // bits down to values
+  public typealias Element = Google_Protobuf_Value
+
+  /// Creates a new `Google_Protobuf_ListValue` from an array literal containing
+  /// `Google_Protobuf_Value` elements.
+  public init(arrayLiteral elements: Element...) {
+    self.init(values: elements)
+  }
+}
+
+extension Google_Protobuf_ListValue: _CustomJSONCodable {
+  internal func encodedJSONString() throws -> String {
+    var jsonEncoder = JSONEncoder()
+    jsonEncoder.append(text: "[")
+    var separator: StaticString = ""
+    for v in values {
+      jsonEncoder.append(staticText: separator)
+      try v.serializeJSONValue(to: &jsonEncoder)
+      separator = ","
+    }
+    jsonEncoder.append(text: "]")
+    return jsonEncoder.stringResult
+  }
+
+  internal mutating func decodeJSON(from decoder: inout JSONDecoder) throws {
+    if decoder.scanner.skipOptionalNull() {
+      return
+    }
+    try decoder.scanner.skipRequiredArrayStart()
+    if decoder.scanner.skipOptionalArrayEnd() {
+      return
+    }
+    while true {
+      var v = Google_Protobuf_Value()
+      try v.decodeJSON(from: &decoder)
+      values.append(v)
+      if decoder.scanner.skipOptionalArrayEnd() {
+        return
+      }
+      try decoder.scanner.skipRequiredComma()
+    }
+  }
+}
+
+extension Google_Protobuf_ListValue {
+  /// Creates a new `Google_Protobuf_ListValue` from the given array of
+  /// `Google_Protobuf_Value` elements.
+  public init(values: [Google_Protobuf_Value]) {
+    self.init()
+    self.values = values
+  }
+
+  public subscript(index: Int) -> Google_Protobuf_Value {
+    get {return values[index]}
+    set(newValue) {values[index] = newValue}
+  }
+}

Sources/SwiftProtobuf/Google_Protobuf_Struct+Extensions.swift

@@ -0,0 +1,74 @@
+// Sources/SwiftProtobuf/Google_Protobuf_Struct+Extensions.swift - Struct extensions
+//
+// Copyright (c) 2014 - 2017 Apple Inc. and the project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See LICENSE.txt for license information:
+// https://github.com/apple/swift-protobuf/blob/master/LICENSE.txt
+//
+// -----------------------------------------------------------------------------
+///
+/// Struct is a well-known message type that can be used to parse or encode
+/// arbitrary JSON objects without a predefined schema.
+///
+// -----------------------------------------------------------------------------
+
+extension Google_Protobuf_Struct: ExpressibleByDictionaryLiteral {
+  public typealias Key = String
+  public typealias Value = Google_Protobuf_Value
+
+  /// Creates a new `Google_Protobuf_Struct` from a dictionary of string keys to
+  /// values of type `Google_Protobuf_Value`.
+  public init(dictionaryLiteral: (String, Google_Protobuf_Value)...) {
+    self.init()
+    for (k,v) in dictionaryLiteral {
+      fields[k] = v
+    }
+  }
+}
+
+extension Google_Protobuf_Struct: _CustomJSONCodable {
+  internal func encodedJSONString() throws -> String {
+    var jsonEncoder = JSONEncoder()
+    jsonEncoder.startObject()
+    var mapVisitor = JSONMapEncodingVisitor(encoder: jsonEncoder)
+    for (k,v) in fields {
+      try mapVisitor.visitSingularStringField(value: k, fieldNumber: 1)
+      try mapVisitor.visitSingularMessageField(value: v, fieldNumber: 2)
+    }
+    mapVisitor.encoder.endObject()
+    return mapVisitor.encoder.stringResult
+  }
+
+  internal mutating func decodeJSON(from decoder: inout JSONDecoder) throws {
+    try decoder.scanner.skipRequiredObjectStart()
+    if decoder.scanner.skipOptionalObjectEnd() {
+      return
+    }
+    while true {
+      let key = try decoder.scanner.nextQuotedString()
+      try decoder.scanner.skipRequiredColon()
+      var value = Google_Protobuf_Value()
+      try value.decodeJSON(from: &decoder)
+      fields[key] = value
+      if decoder.scanner.skipOptionalObjectEnd() {
+        return
+      }
+      try decoder.scanner.skipRequiredComma()
+    }
+  }
+}
+
+extension Google_Protobuf_Struct {
+  /// Creates a new `Google_Protobuf_Struct` from a dictionary of string keys to
+  /// values of type `Google_Protobuf_Value`.
+  public init(fields: [String: Google_Protobuf_Value]) {
+    self.init()
+    self.fields = fields
+  }
+
+  public subscript(index: String) -> Google_Protobuf_Value? {
+    get {return fields[index]}
+    set(newValue) {fields[index] = newValue}
+  }
+}