Add support for sourcemaproot

Gruntfile.js

@@ -127,6 +127,20 @@ module.exports = function(grunt) {
           ]
         }
       },
+      sourcemap4_options: {
+        options: {
+          sourceMap: true,
+          sourceMapName: 'tmp/sourcemap4_embed_map.map',
+          sourceMapRoot: 'file://tmp'
+        },
+        files: {
+          'tmp/sourcemap4_embed': [
+            'test/fixtures/mappedsource_embed',
+            'test/fixtures/file1',
+            'test/fixtures/file2'
+          ]
+        }
+      },
       sourcemap_js: {
         options: {
           banner: '/*\nJS Banner\n*/\n',

tasks/concat.js

@@ -25,7 +25,8 @@ module.exports = function(grunt) {
       process: false,
       sourceMap: false,
       sourceMapName: undefined,
-      sourceMapStyle: 'embed'
+      sourceMapStyle: 'embed',
+      sourceMapRoot: undefined
     });
 
     // Normalize boolean options that accept options objects.

tasks/lib/sourcemap.js

@@ -32,7 +32,8 @@ exports.init = function(grunt) {
     // ensure we're using forward slashes, because these are URLs
     var file = path.relative(path.dirname(this.dest), this.files.dest).replace(/\\/g, '/');
     var generator = new SourceMapGenerator({
-      file: file
+      file: file,
+      sourceRoot: this.options.sourceMapRoot
     });
     this.file = file;
     this.generator = generator;

test/concat_test.js

@@ -83,7 +83,7 @@ exports.concat = {
     test.done();
   },
   sourcemap_options: function(test) {
-    test.expect(5);
+    test.expect(6);
 
     var actual = getNormalizedFile('tmp/sourcemap_inline');
     var expected = getNormalizedFile('test/expected/sourcemap_inline');
@@ -105,6 +105,10 @@ exports.concat = {
     expected = getNormalizedFile('test/expected/sourcemap_css.css.map');
     test.equal(actual, expected, 'should output the css map.');
 
+    actual = getNormalizedFile('tmp/sourcemap4_embed_map.map');
+    expected = getNormalizedFile('test/expected/sourcemap4_embed_map.map');
+    test.equal(actual, expected, 'should include sourceRoot.');
+
     test.done();
   }
 };