[WIP] Fix #39: Generate correct source paths

lib/source-map-support.js

@@ -6,7 +6,10 @@
 var SourceMap = require('source-map').SourceMapGenerator;
 var SourceMapConsumer = require('source-map').SourceMapConsumer;
 var sourceMapResolve = require('source-map-resolve');
+var urix = require('urix');
 var fs = require('fs');
+var path = require('path');
+var url = require('url');
 
 /**
  * Expose `mixin()`.
@@ -22,14 +25,29 @@ module.exports = mixin;
  */
 
 function mixin(compiler) {
-  var file = compiler.options.filename || 'generated.css';
+  var file = compiler.options.filename;
+  compiler.sourcemapPath = typeof compiler.options.sourcemap === 'string'
+    ? compiler.options.sourcemap
+    : file || '.';
   compiler._comment = compiler.comment;
-  compiler.map = new SourceMap({ file: file });
+  compiler.map = new SourceMap({ file: file ? path.basename(file) : null });
   compiler.position = { line: 1, column: 1 };
   compiler.files = {};
   for (var k in exports) compiler[k] = exports[k];
 }
 
+/**
+ * Convert `filepath` to a URL, relative to `this.sourcemapPath`.
+ *
+ * @param {String} filepath
+ * @return {String}
+ * @api private
+ */
+
+exports.relativeUrl = function(filepath) {
+  return url.resolve(urix(this.sourcemapPath), urix(filepath))
+};
+
 /**
  * Update position.
  *
@@ -55,7 +73,7 @@ exports.updatePosition = function(str) {
  */
 
 exports.emit = function(str, pos, startOnly) {
-  var sourceFile = pos && pos.source || 'source.css';
+  var sourceFile = this.relativeUrl(pos && pos.source || 'source.css');
 
   if (pos && pos.start) {
     this.map.addMapping({
@@ -115,8 +133,9 @@ exports.applySourceMaps = function() {
     var originalMap = sourceMapResolve.resolveSync(
       this.files[file], file, fs.readFileSync);
     if (originalMap) {
-      originalMap = new SourceMapConsumer(originalMap.map);
-      this.map.applySourceMap(originalMap, file);
+      var map = new SourceMapConsumer(originalMap.map);
+      var relativeTo = this.relativeUrl(path.dirname(originalMap.sourcesRelativeTo));
+      this.map.applySourceMap(map, file, relativeTo);
     }
   }, this);
 };

package.json

@@ -23,6 +23,7 @@
   },
   "dependencies": {
     "source-map": "~0.1.31",
-    "source-map-resolve": "^0.1.3"
+    "source-map-resolve": "^0.1.3",
+    "urix": "~0.1.0"
   }
 }

test/css-stringify.js

@@ -81,14 +81,14 @@ describe('stringify(obj, {sourcemap: true})', function(){
       column: 0,
       line: 1,
       name: null,
-      source: 'source-map-apply.scss'
+      source: 'test/source-map-apply.scss'
     });
 
     map.originalPositionFor({ line: 2, column: 2 }).should.eql({
       column: 7,
       line: 1,
       name: null,
-      source: 'source-map-apply.scss'
+      source: 'test/source-map-apply.scss'
     });
   });
 });