OpenStep plist decoding via PropertyListDecoder is not available on Windows and Linux (#1002)

resolves: rdar://136243566

Co-authored-by: Kevin Perry <kperry@apple.com>

Author: iCharlesHu

Sources/FoundationEssentials/PropertyList/OpenStepPlist.swift

@@ -302,12 +302,7 @@ private func parseOctal(startingWith ch: UInt16, _ pInfo: inout _ParseInfo) -> U
         }
     }
 
-    // A probably more expensive replacement for CFStringEncodingBytesToUnicode(kCFStringEncodingNextStepLatin, …)
-    guard let str = String(bytes: [num], encoding: .nextstep) else {
-        pInfo.err = OpenStepPlistError("Unable to convert octet-stream while parsing plist")
-        return 0
-    }
-    return str.utf16.first ?? 0
+    return .init(nextStep: num)
 }
 
 private func parseU16Scalar(_ pInfo: inout _ParseInfo) -> UInt16 {

Sources/FoundationEssentials/PropertyList/PlistDecoder.swift

@@ -158,7 +158,6 @@ open class PropertyListDecoder {
             format = .xml
             return result
         }, openstep: { utf16View in
-#if FOUNDATION_FRAMEWORK
             let value: Any
             do {
                 value = try __ParseOldStylePropertyList(utf16: utf16View)
@@ -168,10 +167,6 @@ open class PropertyListDecoder {
             let decoder = __PlistDictionaryDecoder(referencing: value, at: [], options: options)
             format = .openStep
             return try doDecode(decoder)
-#else
-            // Unsupported until __PlistDictionaryDecoder is available
-            throw DecodingError.dataCorrupted(.init(codingPath: [], debugDescription: "The openStep format is unsupported on this platform."))
-#endif
         })
     }
 

Sources/FoundationEssentials/PropertyList/PlistDictionaryDecoder.swift

@@ -10,9 +10,6 @@
 //
 //===----------------------------------------------------------------------===//
 
-// Relies on NSNumber
-#if FOUNDATION_FRAMEWORK
-
 // MARK: - __PlistDictionaryDecoder
 
 internal class __PlistDictionaryDecoder : Decoder, _PlistDecoderEntryPointProtocol {
@@ -899,10 +896,14 @@ extension __PlistDictionaryDecoder {
             }
             return converted
         }
+
+        // Relies on NSNumber
+        #if FOUNDATION_FRAMEWORK
         if let ns = value as? NSNumber {
             // This was some other NSNumber value that couldn't fit in T.
             throw DecodingError.dataCorrupted(DecodingError.Context(codingPath: self.codingPath, debugDescription: "Parsed property list number <\(ns)> does not fit in \(type)."))
         }
+        #endif
 
         throw DecodingError._typeMismatch(at: self.codingPath, expectation: type, reality: value)
     }
@@ -966,10 +967,14 @@ extension __PlistDictionaryDecoder {
             }
             return converted
         }
+
+        // Relies on NSNumber
+        #if FOUNDATION_FRAMEWORK
         if let ns = value as? NSNumber {
             // This was some other NSNumber value that couldn't fit in T.
             throw DecodingError.dataCorrupted(DecodingError.Context(codingPath: self.codingPath, debugDescription: "Parsed property list number <\(ns)> does not fit in \(type)."))
         }
+        #endif
 
         throw DecodingError._typeMismatch(at: self.codingPath, expectation: type, reality: value)
     }
@@ -1028,5 +1033,3 @@ extension __PlistDictionaryDecoder {
         return try type.init(from: self, configuration: configuration)
     }
 }
-
-#endif // FOUNDATION_FRAMEWORK

Sources/FoundationEssentials/String/StringProtocol+Essentials.swift

@@ -74,6 +74,21 @@ extension UInt8 {
     }
 }
 
+extension UInt16 {
+    init(nextStep codepoint: UInt8) {
+        if codepoint < 128 {
+            self = Self(codepoint)
+        } else {
+            let tableOffset = Int(codepoint - 128)
+            self = withUnsafePointer(to: _stringshims_nextstep_mapping) {
+                $0.withMemoryRebound(to: Self.self, capacity: Int(_STRINGSHIMS_NEXTSTEP_MAP_SIZE)) {
+                    $0.advanced(by: tableOffset).pointee
+                }
+            }
+        }
+    }
+}
+
 // These provides concrete implementations for String and Substring, enhancing performance over generic StringProtocol.
 
 @available(FoundationPreview 0.4, *)

Sources/_FoundationCShims/include/string_shims.h

@@ -46,6 +46,9 @@ INTERNAL float _stringshims_strtof_l(const char * _Nullable __restrict nptr, cha
 #define _STRINGSHIMS_MACROMAN_MAP_SIZE 129
 INTERNAL const uint8_t _stringshims_macroman_mapping[_STRINGSHIMS_MACROMAN_MAP_SIZE][3];
 
+#define _STRINGSHIMS_NEXTSTEP_MAP_SIZE 128
+INTERNAL const uint16_t _stringshims_nextstep_mapping[_STRINGSHIMS_NEXTSTEP_MAP_SIZE];
+
 #ifdef __cplusplus
 }
 #endif

Sources/_FoundationCShims/string_shims.c

@@ -234,3 +234,23 @@ const uint8_t _stringshims_macroman_mapping[_STRINGSHIMS_MACROMAN_MAP_SIZE][3] =
     { 0xEF, 0xAC, 0x81 }, /* LATIN SMALL LIGATURE FI */
     { 0xEF, 0xAC, 0x82 }, /* LATIN SMALL LIGATURE FL */
 };
+
+// NEXTSTEP string encoding character mapping, offset by 128.
+const uint16_t _stringshims_nextstep_mapping[_STRINGSHIMS_NEXTSTEP_MAP_SIZE] = {
+    0x00A0, 0x00C0, 0x00C1, 0x00C2, 0x00C3, 0x00C4, 0x00C5, 0x00C7,
+    0x00C8, 0x00C9, 0x00CA, 0x00CB, 0x00CC, 0x00CD, 0x00CE, 0x00CF,
+    0x00D0, 0x00D1, 0x00D2, 0x00D3, 0x00D4, 0x00D5, 0x00D6, 0x00D9,
+    0x00DA, 0x00DB, 0x00DC, 0x00DD, 0x00DE, 0x00B5, 0x00D7, 0x00F7,
+    0x00A9, 0x00A1, 0x00A2, 0x00A3, 0x2044, 0x00A5, 0x0192, 0x00A7,
+    0x00A4, 0x2019, 0x201C, 0x00AB, 0x2039, 0x203A, 0xFB01, 0xFB02,
+    0x00AE, 0x2013, 0x2020, 0x2021, 0x00B7, 0x00A6, 0x00B6, 0x2022,
+    0x201A, 0x201E, 0x201D, 0x00BB, 0x2026, 0x2030, 0x00AC, 0x00BF,
+    0x00B9, 0x02CB, 0x00B4, 0x02C6, 0x02DC, 0x00AF, 0x02D8, 0x02D9,
+    0x00A8, 0x00B2, 0x02DA, 0x00B8, 0x00B3, 0x02DD, 0x02DB, 0x02C7,
+    0x2014, 0x00B1, 0x00BC, 0x00BD, 0x00BE, 0x00E0, 0x00E1, 0x00E2,
+    0x00E3, 0x00E4, 0x00E5, 0x00E7, 0x00E8, 0x00E9, 0x00EA, 0x00EB,
+    0x00EC, 0x00C6, 0x00ED, 0x00AA, 0x00EE, 0x00EF, 0x00F0, 0x00F1,
+    0x0141, 0x00D8, 0x0152, 0x00BA, 0x00F2, 0x00F3, 0x00F4, 0x00F5,
+    0x00F6, 0x00E6, 0x00F9, 0x00FA, 0x00FB, 0x0131, 0x00FC, 0x00FD,
+    0x0142, 0x00F8, 0x0153, 0x00DF, 0x00FE, 0x00FF, 0xFFFD, 0xFFFD
+};

Tests/FoundationEssentialsTests/PropertyListEncoderTests.swift

@@ -858,9 +858,6 @@ class TestPropertyListEncoder : XCTestCase {
         }
     }
 
-#if FOUNDATION_FRAMEWORK
-    // Requires old style plist support
-    // Requires "NEXTStep" decoding in String(bytes:encoding:) for decoding the octal characters
 
     func test_oldStylePlist_invalid() {
         let data = "goodbye cruel world".data(using: String._Encoding.utf16)!
@@ -968,7 +965,6 @@ string3 = "Good evening"; // Test
             XCTFail("Unexpected error: \(error)")
         }
     }
-#endif
 
 #if FOUNDATION_FRAMEWORK
     // Requires __PlistDictionaryDecoder