Final fixes

Author: fabianfett

Sources/Foundation/JSONSerialization+Parser.swift

@@ -128,7 +128,11 @@ internal struct JSONParser {
                 // consume the comma
                 reader.moveReaderIndex(forwardBy: 1)
                 // consume the whitespace before the next value
-                try reader.consumeWhitespace()
+                if try reader.consumeWhitespace() == ._closebracket {
+                    // the foundation json implementation does support trailing commas
+                    reader.moveReaderIndex(forwardBy: 1)
+                    return array
+                }
                 continue
             default:
                 throw JSONError.unexpectedCharacter(ascii: ascii, characterIndex: reader.readerIndex)
@@ -178,7 +182,11 @@ internal struct JSONParser {
                 return object
             case ._comma:
                 reader.moveReaderIndex(forwardBy: 1)
-                try reader.consumeWhitespace()
+                if try reader.consumeWhitespace() == ._closebrace {
+                    // the foundation json implementation does support trailing commas
+                    reader.moveReaderIndex(forwardBy: 1)
+                    return object
+                }
                 continue
             default:
                 throw JSONError.unexpectedCharacter(ascii: commaOrBrace, characterIndex: reader.readerIndex)
@@ -637,6 +645,7 @@ extension UInt8 {
 
 
 enum JSONError: Swift.Error, Equatable {
+    case cannotConvertInputDataToUTF8
     case unexpectedCharacter(ascii: UInt8, characterIndex: Int)
     case unexpectedEndOfFile
     case tooManyNestedArraysOrDictionaries(characterIndex: Int)

Sources/Foundation/JSONSerialization.swift

@@ -185,16 +185,18 @@ open class JSONSerialization : NSObject {
         do {
             let jsonValue = try data.withUnsafeBytes { (ptr) -> JSONValue in
                 let (encoding, advanceBy) = JSONSerialization.detectEncoding(ptr)
-                guard encoding == .utf8, advanceBy == 0 else {
-                    let newPtr = ptr[advanceBy..<ptr.count]
-                    let json = String(bytes: newPtr, encoding: encoding)!
-                    return try json.utf8.withContiguousStorageIfAvailable { (utf8) -> JSONValue in
-                        var parser = JSONParser(bytes: Array(utf8))
-                        return try parser.parse()
-                    }!
+                
+                if encoding == .utf8 {
+                    // we got utf8... happy path
+                    var parser = JSONParser(bytes: Array(ptr[advanceBy..<ptr.count]))
+                    return try parser.parse()
                 }
-
-                var parser = JSONParser(bytes: Array(ptr))
+                
+                guard let utf8String = String(bytes: ptr[advanceBy..<ptr.count], encoding: encoding) else {
+                    throw JSONError.cannotConvertInputDataToUTF8
+                }
+                
+                var parser = JSONParser(bytes: Array(utf8String.utf8))
                 return try parser.parse()
             }
 
@@ -205,6 +207,10 @@ open class JSONSerialization : NSObject {
             return try jsonValue.toObjcRepresentation(options: opt)
         } catch let error as JSONError {
             switch error {
+            case .cannotConvertInputDataToUTF8:
+                throw NSError(domain: NSCocoaErrorDomain, code: CocoaError.propertyListReadCorrupt.rawValue, userInfo: [
+                    NSDebugDescriptionErrorKey : "Cannot convert input string to valid utf8 input."
+                ])
             case .unexpectedEndOfFile:
                 throw NSError(domain: NSCocoaErrorDomain, code: CocoaError.propertyListReadCorrupt.rawValue, userInfo: [
                     NSDebugDescriptionErrorKey : "Unexpected end of file during JSON parse."

Tests/Foundation/Tests/TestJSONSerialization.swift

@@ -623,9 +623,13 @@ extension TestJSONSerialization {
         let subject = "[1.1e547]"
         let data = Data(subject.utf8)
 
-        var numbers: [NSNumber]?
-        XCTAssertNoThrow(numbers = try getjsonObjectResult(data, objectType) as? [NSNumber])
-        XCTAssertEqual(numbers?.first?.doubleValue.isInfinite, true)
+        XCTAssertThrowsError(try getjsonObjectResult(data, objectType)) { error in
+            guard let nserror = (error as? NSError) else {
+                return XCTFail("Unexpected error: \(error)")
+            }
+            XCTAssertEqual(nserror.domain, NSCocoaErrorDomain)
+            XCTAssertEqual(CocoaError(_nsError: nserror).code, .propertyListReadCorrupt)
+        }
     }
 
     func deserialize_numbers_as_reference_types(objectType: ObjectType) {