New JavaScript CharStreams functions

runtime-testsuite/test/org/antlr/v4/test/runtime/javascript/browser/BaseBrowserTest.java

@@ -678,7 +678,7 @@ protected void writeParserTestFile(String parserName,
 			"			test = function() {\r\n" +
 			"				document.getElementById('output').value = ''\r\n" +
 			"				var input = document.getElementById('input').value;\r\n" +
-			"			var stream = new antlr4.InputStream(input, true);\n" +
+			"			var stream = antlr4.CharStreams.fromString(input);\n" +
 			"    			var lexer = new " + lexerName + "." + lexerName + "(stream);\n" +
 			"				lexer._listeners = [new listener()];\r\n" +
 			"    			var tokens = new antlr4.CommonTokenStream(lexer);\n" +
@@ -737,7 +737,7 @@ protected void writeLexerTestFile(String lexerName, boolean showDFA) {
 			"			test = function() {\r\n" +
 			"				document.getElementById('output').value = ''\r\n" +
 			"				var input = document.getElementById('input').value;\r\n" +
-			"			var chars = new antlr4.InputStream(input, true);\r\n" +
+			"			var chars = antlr4.CharStreams.fromString(input);\r\n" +
 			"    			var lexer = new " + lexerName + "." + lexerName + "(chars);\r\n" +
 			"				lexer._listeners = [new listener()];\r\n" +
 			"    			var stream = new antlr4.CommonTokenStream(lexer);\r\n" +

runtime/JavaScript/src/antlr4/CharStreams.js

@@ -0,0 +1,71 @@
+//
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+//
+
+var InputStream = require('./InputStream').InputStream;
+
+var isNodeJs = typeof window === 'undefined' && typeof importScripts === 'undefined';
+var fs = isNodeJs ? require("fs") : null;
+
+// Utility functions to create InputStreams from various sources.
+//
+// All returned InputStreams support the full range of Unicode
+// up to U+10FFFF (the default behavior of InputStream only supports
+// code points up to U+FFFF).
+var CharStreams = {
+  // Creates an InputStream from a string.
+  fromString: function(str) {
+    return InputStream(str, true);
+  },
+
+  // Asynchronously creates an InputStream from a blob given the
+  // encoding of the bytes in that blob (defaults to 'utf8' if
+  // encoding is null).
+  //
+  // Invokes onLoad(result) on success, onError(error) on
+  // failure.
+  fromBlob: function(blob, encoding, onLoad, onError) {
+    var reader = FileReader();
+    reader.onload = function(e) {
+      var is = InputStream(e.target.result, true);
+      onLoad(is);
+    };
+    reader.onerror = onError;
+    reader.readAsText(blob, encoding);
+  },
+
+  // Creates an InputStream from a Buffer given the
+  // encoding of the bytes in that buffer (defaults to 'utf8' if
+  // encoding is null).
+  fromBuffer: function(buffer, encoding) {
+    return InputStream(buffer.toString(encoding), true);
+  },
+
+  // Asynchronously creates an InputStream from a file on disk given
+  // the encoding of the bytes in that file (defaults to 'utf8' if
+  // encoding is null).
+  //
+  // Invokes callback(error, result) on completion.
+  fromPath: function(path, encoding, callback) {
+    fs.readFile(path, encoding, function(err, data) {
+      var is = null;
+      if (data !== null) {
+        is = InputStream(data, true);
+      }
+      callback(err, is);
+    });
+  },
+
+  // Synchronously creates an InputStream given a path to a file
+  // on disk and the encoding of the bytes in that file (defaults to
+  // 'utf8' if encoding is null).
+  fromPathSync: function(path, encoding) {
+    var data = fs.readFileSync(path, encoding);
+    return InputStream(data, true);
+  }
+};
+
+exports.CharStreams = CharStreams;

runtime/JavaScript/src/antlr4/index.js

@@ -9,6 +9,7 @@ exports.fromcodepoint = require('./polyfills/fromcodepoint');
 exports.tree = require('./tree/index');
 exports.error = require('./error/index');
 exports.Token = require('./Token').Token;
+exports.CharStreams = require('./CharStreams').CharStreams;
 exports.CommonToken = require('./Token').CommonToken;
 exports.InputStream = require('./InputStream').InputStream;
 exports.FileStream = require('./FileStream').FileStream;