Report errors in ANTLRFileStream.

Change the initializer to ANTLRFileStream so that it throws any errors that
occur while reading the file.  Previously, it was just dropping any errors on
the floor (inside Utils.readFile).

Remove Utils.readFile, it's not used anywhere else.

runtime-testsuite/test/org/antlr/v4/test/runtime/swift/BaseSwiftTest.java

@@ -281,7 +281,7 @@ public class BaseSwiftTest implements RuntimeTestSupport {
 						"\n" +
 						"do {\n" +
 						"let args = CommandLine.arguments\n" +
-						"let input = ANTLRFileStream(args[1])\n" +
+						"let input = try ANTLRFileStream(args[1])\n" +
 						"let lex = <lexerName>(input)\n" +
 						"let tokens = CommonTokenStream(lex)\n" +
 						"<createParser>\n" +
@@ -327,7 +327,7 @@ public class BaseSwiftTest implements RuntimeTestSupport {
 
 						"setbuf(stdout, nil)\n" +
 						"let args = CommandLine.arguments\n" +
-						"let input = ANTLRFileStream(args[1])\n" +
+						"let input = try ANTLRFileStream(args[1])\n" +
 						"let lex = <lexerName>(input)\n" +
 						"let tokens = CommonTokenStream(lex)\n" +
 

runtime/Swift/Sources/Antlr4/ANTLRFileStream.swift

@@ -9,30 +9,18 @@
 import Foundation
 
 public class ANTLRFileStream: ANTLRInputStream {
-    internal var fileName: String
+    private let fileName: String
 
-    public convenience override init(_ fileName: String) {
+    public init(_ fileName: String, _ encoding: String.Encoding? = nil) throws {
-        self.init(fileName, nil)
-    }
-
-    public init(_ fileName: String, _ encoding: String.Encoding?) {
         self.fileName = fileName
         super.init()
-        load(fileName, encoding)
+        let fileContents = try String(contentsOfFile: fileName, encoding: encoding ?? .utf8)
-    }
+        data = Array(fileContents)
-
+        n = data.count
-    public func load(_ fileName: String, _ encoding: String.Encoding?) {
-        if encoding != nil {
-            data = Utils.readFile(fileName, encoding!)
-        } else {
-            data = Utils.readFile(fileName)
-        }
-        self.n = data.count
     }
 
     override
     public func getSourceName() -> String {
         return fileName
     }
-
 }

runtime/Swift/Sources/Antlr4/misc/Utils.swift

@@ -34,19 +34,6 @@ public class Utils {
     }
 
 
-    public static func readFile(_ path: String, _ encoding: String.Encoding = String.Encoding.utf8) -> [Character] {
-
-        var fileContents: String
-
-        do {
-            fileContents = try String(contentsOfFile: path, encoding: encoding)
-        } catch {
-            return [Character]()
-        }
-
-        return Array(fileContents.characters)
-    }
-
     public static func toMap(_ keys: [String]) -> Dictionary<String, Int> {
         var m = Dictionary<String, Int>()
         for (index,v) in keys.enumerated() {