Add bool support to the proto decoder. (#32)

Author: jverkoey

Tests/BinaryCodableTests/protobufs/Message.swift

@@ -26,6 +26,7 @@ struct Message: ProtoDecodable {
   var sint64Value: Int64?
   var fixed32Value: UInt32?
   var fixed64Value: UInt64?
+  var boolValue: Bool?
   var missingValue: Int32?
 
   static func fieldDescriptor(for key: CodingKey) -> Field? {
@@ -43,6 +44,7 @@ struct Message: ProtoDecodable {
     case .sint64Value: return Field(number: 8, type: .sint64)
     case .fixed32Value: return Field(number: 9, type: .fixed32)
     case .fixed64Value: return Field(number: 10, type: .fixed64)
+    case .boolValue: return Field(number: 13, type: .bool)
     case .missingValue: return Field(number: 20, type: .int32)
     }
   }

Tests/BinaryCodableTests/protobufs/ProtoDecoderSupport.swift

@@ -28,6 +28,7 @@ struct Field {
     case sint64
     case fixed32
     case fixed64
+    case bool
   }
   let type: FieldType
 }
@@ -103,7 +104,7 @@ private struct ProtoKeyedDecodingContainer<Key: CodingKey>: KeyedDecodingContain
   }
 
   func decode(_ type: Bool.Type, forKey key: Key) throws -> Bool {
-    preconditionFailure("Unimplemented")
+    return try decodeFixedWidthInteger(UInt8.self, forKey: key) != 0
   }
 
   func decode(_ type: String.Type, forKey key: Key) throws -> String {
@@ -197,7 +198,8 @@ private struct ProtoKeyedDecodingContainer<Key: CodingKey>: KeyedDecodingContain
     case (.int32, .varint(let rawValue)),
          (.int64, .varint(let rawValue)),
          (.uint32, .varint(let rawValue)),
-         (.uint64, .varint(let rawValue)): return T.init(clamping: rawValue)
+         (.uint64, .varint(let rawValue)),
+         (.bool, .varint(let rawValue)): return T.init(clamping: rawValue)
     case (.sint32, .varint(let rawValue)): return T.init(clamping: Int32(rawValue >> 1) ^ -Int32(rawValue & 1))
     case (.sint64, .varint(let rawValue)): return T.init(clamping: Int64(rawValue >> 1) ^ -Int64(rawValue & 1))
     case (.fixed32, .fixed32(let rawValue)): return T.init(clamping: rawValue)

Tests/BinaryCodableTests/protobufs/ProtobufTests.swift

@@ -586,6 +586,7 @@ class ProtobufTests: XCTestCase {
           sint32 sint64_value = 8;
           fixed32 fixed32_value = 9;
           fixed64 fixed64_value = 10;
+          bool bool_value = 13;
           int32 missing_value = 20;
         }
         """, message: "value", content: """
@@ -599,6 +600,7 @@ class ProtobufTests: XCTestCase {
         sint64_value: 268435456
         fixed32_value: \(UInt32.max)
         fixed64_value: \(UInt64.max)
+        bool_value: true
         """)
       let decoder = ProtoDecoder()
 
@@ -616,6 +618,10 @@ class ProtobufTests: XCTestCase {
       XCTAssertEqual(message.sint64Value, 268435456)
       XCTAssertEqual(message.fixed32Value, UInt32.max)
       XCTAssertEqual(message.fixed64Value, UInt64.max)
+      XCTAssertNotNil(message.boolValue)
+      if let boolValue = message.boolValue {
+        XCTAssertTrue(boolValue)
+      }
       XCTAssertNil(message.missingValue)
     } catch let error {
       XCTFail(String(describing: error))