Fix #63 - OS X webpack sourcemap issue

adapter/sourceMaps/sourceMaps.ts

@@ -260,13 +260,7 @@ class SourceMap {
 
         // Overwrite the sourcemap's sourceRoot with the version that's resolved to an absolute path,
         // so the work above only has to be done once
-        if (this._absSourceRoot.startsWith('/')) {
-            // OSX paths
-            sm.sourceRoot = 'file://' + this._absSourceRoot;
-        } else {
-            // Windows paths
-            sm.sourceRoot = 'file:///' + this._absSourceRoot;
-        }
+        sm.sourceRoot = utils.pathToFileURL(this._absSourceRoot);
 
         sm.sources = sm.sources.map((sourcePath: string) => {
             // special-case webpack:/// prefixed sources which is kind of meaningless
@@ -339,7 +333,7 @@ class SourceMap {
 	 */
 	public generatedPositionFor(src: string, line: number, column: number, bias = Bias.GREATEST_LOWER_BOUND): SourceMap.Position {
         if (this._sourcesAreURLs) {
-            src = 'file:///' + src;
+            src = utils.pathToFileURL(src);
         } else if (this._absSourceRoot) {
             // make input path relative to sourceRoot
 			src = Path.relative(this._absSourceRoot, src);

test/webkit/utilities.test.ts

@@ -439,4 +439,16 @@ suite('Utilities', () => {
             assert.equal(Utilities.lstrip('asdf', 'sdf'), 'asdf');
         });
     });
+
+    suite('pathToFileURL', () => {
+        const Utilities = getUtilities();
+
+        test('converts windows-style paths', () => {
+            assert.equal(Utilities.pathToFileURL('c:/code/app.js'), 'file:///c:/code/app.js');
+        });
+
+        test('converts unix-style paths', () => {
+            assert.equal(Utilities.pathToFileURL('/code/app.js'), 'file:///code/app.js');
+        });
+    });
 });

webkit/utilities.ts

@@ -406,3 +406,13 @@ export function lstrip(s: string, lStr: string): string {
         s.substr(lStr.length) :
         s;
 }
+
+/**
+ * Convert a local path to a file URL, like
+ * C:/code/app.js => file:///C:/code/app.js
+ * /code/app.js => file:///code/app.js
+ */
+export function pathToFileURL(path: string): string {
+    return (path.startsWith('/') ? 'file://' : 'file:///') +
+        path;
+}