[wasm] Miscellaneous Foundation fixes

* Removed too conservative guards
* Port `Host` class
* Add `arch(wasm32)` to 32-bit arch conditions

Author: kateinoigakukun

Sources/Foundation/Host.swift

@@ -91,6 +91,8 @@ open class Host: NSObject {
             return "localhost"
         }
         return String(cString: hostname)
+#elseif os(WASI) // WASI does not have uname
+        return "localhost"
 #else
         let hname = UnsafeMutablePointer<Int8>.allocate(capacity: Int(NI_MAXHOST))
         defer {
@@ -170,6 +172,9 @@ open class Host: NSObject {
         }
         _names = [info]
         _resolved = true
+#elseif os(WASI) // WASI does not have getifaddrs
+        _names = [info]
+        _resolved = true
 #else
         var ifaddr: UnsafeMutablePointer<ifaddrs>? = nil
         if getifaddrs(&ifaddr) != 0 {
@@ -267,6 +272,11 @@ open class Host: NSObject {
 
           _resolved = true
         }
+#elseif os(WASI) // WASI does not have getaddrinfo
+        if let info = _info {
+            _names = [info]
+            _resolved = true
+        }
 #else
         if let info = _info {
             var flags: Int32 = 0

Sources/Foundation/NSCharacterSet.swift

@@ -184,7 +184,6 @@ open class NSCharacterSet : NSObject, NSCopying, NSMutableCopying, NSSecureCodin
         _CFCharacterSetInitWithBitmapRepresentation(_cfMutableObject, data._cfObject)
     }
 
-#if !os(WASI)
     public convenience init?(contentsOfFile fName: String) {
         do {
            let data = try Data(contentsOf: URL(fileURLWithPath: fName))
@@ -330,7 +329,6 @@ open class NSCharacterSet : NSObject, NSCopying, NSMutableCopying, NSSecureCodin
             aCoder.encode(true, forKey: .characterSetIsInvertedKey)
         }
     }
-#endif
 
     open func characterIsMember(_ aCharacter: unichar) -> Bool {
         return longCharacterIsMember(UInt32(aCharacter))

Sources/Foundation/NSKeyedArchiver.swift

@@ -150,10 +150,6 @@ open class NSKeyedArchiver : NSCoder {
     /// - Returns:      `true` if the operation was successful, otherwise `false`.
     @available(swift, deprecated: 9999, renamed: "archivedData(withRootObject:requiringSecureCoding:)")
     open class func archiveRootObject(_ rootObject: Any, toFile path: String) -> Bool {
-#if os(WASI)
-        assertionFailure("\(#function) does not support file access on WASI")
-        return false
-#else
         var fd : Int32 = -1
         var auxFilePath : String
         var finishedEncoding : Bool = false
@@ -187,7 +183,6 @@ open class NSKeyedArchiver : NSCoder {
         finishedEncoding = keyedArchiver._flags.contains(.finishedEncoding)
 
         return finishedEncoding
-#endif
     }
 
     public convenience init(requiringSecureCoding: Bool) {
@@ -228,13 +223,8 @@ open class NSKeyedArchiver : NSCoder {
                 success = true
             }
         } else {
-#if !os(WASI)
             let stream = unsafeBitCast(self._stream, to: CFWriteStream.self)
             success = CFPropertyListWrite(plist, stream, kCFPropertyListXMLFormat_v1_0, 0, nil) > 0
-#else
-            assertionFailure("\(#function) only supports data streams on WASI")
-            return false
-#endif
         }
 
         return success

Sources/Foundation/NSPathUtilities.swift

@@ -75,11 +75,9 @@ public func NSTemporaryDirectory() -> String {
       }
     }
 #endif
-#if !os(WASI)
     if let tmpdir = ProcessInfo.processInfo.environment["TMPDIR"] {
         return normalizedPath(with: tmpdir)
     }
-#endif
 #if os(Android)
     // Bionic uses /data/local/tmp/ as temporary directory. TMPDIR is rarely
     // defined.
@@ -433,7 +431,6 @@ extension NSString {
         return paths.map(appendingPathComponent)
     }
 
-#if !os(WASI)
     /// - Experiment: This is a draft API currently under consideration for official import into Foundation
     /// - Note: Since this API is under consideration it may be either removed or revised in the near future
     public func completePath(into outputName: inout String?, caseSensitive flag: Bool, matchesInto outputArray: inout [String], filterTypes: [String]?) -> Int {
@@ -536,7 +533,6 @@ extension NSString {
             return { $0.lowercased().hasPrefix(prefix) }
         }
     }
-#endif
 
     internal func _longestCommonPrefix(_ strings: [String], caseSensitive: Bool) -> String? {
         guard !strings.isEmpty else {
@@ -584,11 +580,9 @@ extension NSString {
         return path + "/"
     }
 
-#if !os(WASI)
     public var fileSystemRepresentation: UnsafePointer<Int8> {
         return FileManager.default.fileSystemRepresentation(withPath: self._swiftObject)
     }
-#endif
 
     public func getFileSystemRepresentation(_ cname: UnsafeMutablePointer<Int8>, maxLength max: Int) -> Bool {
 #if os(Windows)

Sources/Foundation/NSString.swift

@@ -25,11 +25,7 @@ func NSLocalizedString(_ key: String,
                        bundle: Bundle = Bundle.main,
                        value: String = "",
                        comment: String) -> String {
-#if os(WASI)
-    return key
-#else
     return bundle.localizedString(forKey: key, value: value, table: tableName)
-#endif
 }
 
 internal let kCFStringEncodingMacRoman =  CFStringBuiltInEncodings.macRoman.rawValue

Sources/Foundation/ScannerAPI.swift

@@ -43,7 +43,7 @@ extension Scanner {
         if let value = scanInt64(representation: representation) {
             return Int(value)
         }
-        #elseif arch(i386) || arch(arm)
+        #elseif arch(i386) || arch(arm) || arch(wasm32)
         if let value = scanInt32(representation: representation) {
             return Int(value)
         }