gulp-sourcemap support (#94)

* gulp-sourcemap support

* handling of pre-existing source maps.

* Documented gulp-sourcemaps support

* simplified file options handling

README.md

@@ -71,6 +71,23 @@ gulp.task('test', ['pre-test'], function () {
 });
 ```
 
+#### Source Maps
+gulp-istanbul supports [gulp-sourcemaps][gulp-sourcemaps] when instrumenting:
+
+
+```javascript
+gulp.task('pre-test', function () {
+  return gulp.src(['lib/**/*.js'])
+    // optionally load existing source maps
+    .pipe(sourcemaps.init())
+    // Covering files
+    .pipe(istanbul())
+    .pipe(sourcemaps.write('.'))
+    // Write the covered files to a temporary directory
+    .pipe(gulp.dest('test-tmp/'));
+});
+```
+
 API
 --------------
 
@@ -305,6 +322,7 @@ License
 
 [istanbul]: http://gotwarlost.github.io/istanbul/
 [gulp]: https://github.com/gulpjs/gulp
+[gulp-sourcemaps]: https://github.com/floridoo/gulp-sourcemaps
 
 [npm-url]: https://npmjs.org/package/gulp-istanbul
 [npm-image]: https://badge.fury.io/js/gulp-istanbul.svg

index.js

@@ -8,6 +8,7 @@ var checker = require('istanbul-threshold-checker');
 var istanbul = require('istanbul');
 var gutil = require('gulp-util');
 var _ = require('lodash');
+var applySourceMap = require('vinyl-sourcemaps-apply');
 var Report = istanbul.Report;
 var Collector = istanbul.Collector;
 var PluginError = gutil.PluginError;
@@ -23,22 +24,41 @@ var plugin = module.exports = function (opts) {
   });
   opts.includeUntested = opts.includeUntested === true;
 
-  var instrumenter = new opts.instrumenter(opts);
-
   return through(function (file, enc, cb) {
+    var fileContents = file.contents.toString();
+    var fileOpts = _.cloneDeep(opts);
+
+    if (file.sourceMap) {
+      fileOpts = _.defaultsDeep(fileOpts, {
+        codeGenerationOptions: {
+          sourceMap: file.sourceMap.file,
+          sourceMapWithCode: true,
+          sourceContent: fileContents,
+          sourceMapRoot: file.sourceMap.sourceRoot,
+          file: file.path
+        }
+      });
+    }
+    var instrumenter = new opts.instrumenter(fileOpts);
+
     cb = _.once(cb);
     if (!(file.contents instanceof Buffer)) {
       return cb(new PluginError(PLUGIN_NAME, 'streams not supported'));
     }
 
-    instrumenter.instrument(file.contents.toString(), file.path, function (err, code) {
+    instrumenter.instrument(fileContents, file.path, function (err, code) {
       if (err) {
         return cb(new PluginError(
           PLUGIN_NAME,
           'Unable to parse ' + file.path + '\n\n' + err.message + '\n'
         ));
       }
 
+      var sourceMap = instrumenter.lastSourceMap();
+      if (sourceMap !== null) {
+          applySourceMap(file, sourceMap.toString());
+      }
+
       file.contents = new Buffer(code);
 
       // Parse the blank coverage object from the instrumented file and save it

package.json

@@ -32,11 +32,13 @@
     "istanbul": "^0.4.0",
     "istanbul-threshold-checker": "^0.1.0",
     "lodash": "^4.0.0",
-    "through2": "^2.0.0"
+    "through2": "^2.0.0",
+    "vinyl-sourcemaps-apply": "^0.2.1"
   },
   "devDependencies": {
     "gulp": "^3.6.2",
     "gulp-mocha": "^2.0.0",
+    "gulp-sourcemaps": "^1.6.0",
     "isparta": "^3.0.0",
     "jshint": "^2.5.0",
     "mocha": "^2.0.1",

test/main.js

@@ -8,6 +8,7 @@ var gulp = require('gulp');
 var istanbul = require('../');
 var isparta = require('isparta');
 var mocha = require('gulp-mocha');
+var sourcemaps = require('gulp-sourcemaps');
 var Report = require('istanbul').Report;
 
 var out = process.stdout.write.bind(process.stdout);
@@ -19,16 +20,18 @@ describe('gulp-istanbul', function () {
     require.cache = {};
   });
 
-  var libFile = new gutil.File({
-    path: 'test/fixtures/lib/add.js',
-    cwd: 'test/',
-    base: 'test/fixtures/lib',
-    contents: fs.readFileSync('test/fixtures/lib/add.js')
-  });
+  var libFile;
 
   describe('istanbul()', function () {
     beforeEach(function () {
       this.stream = istanbul();
+      libFile = new gutil.File({
+        path: 'test/fixtures/lib/add.js',
+        cwd: 'test/',
+        base: 'test/fixtures/lib',
+        contents: fs.readFileSync('test/fixtures/lib/add.js')
+      });
+
     });
 
     it('instrument files', function (done) {
@@ -74,6 +77,51 @@ describe('gulp-istanbul', function () {
       this.stream.write(srcFile);
       this.stream.end();
     });
+
+    it('is compatible to gulp-sourcemaps', function(done) {
+      var initStream = sourcemaps.init();
+      var sourceMapStream = initStream.pipe(this.stream);
+      sourceMapStream.on('data', function (file) {
+        assert(file.sourceMap !== undefined);
+        assert.equal(file.sourceMap.file, file.path);
+        done();
+      });
+
+      initStream.write(libFile);
+      initStream.end();
+    });
+
+    it('handles existing source maps', function(done) {
+        var initStream = sourcemaps.init();
+        var sourceMapStream = initStream.pipe(this.stream);
+        sourceMapStream.on('data', function (file) {
+          assert.equal(file.sourceMap.sourceRoot, 'testSourceRoot');
+          assert(file.sourceMap.sources.indexOf('testInputFile.js') >= 0);
+          done();
+        });
+
+        libFile.sourceMap = {
+          version: 3,
+          sources: [ 'add.js' ],
+          names: [ 'exports', 'add', 'a', 'b', 'missed' ],
+          mappings: ';;;;;;;;;AAEAA,OAAA,CAAQC,GAAR,GAAc,UAAUC,CAAV,EAAaC,CAAb,EAAgB;AAAA,I,sCAAA;AAAA,I,sCAAA;AAAA,IAC5B,OAAOD,CAAA,GAAIC,CAAX,CAD4B;AAAA,CAA9B,C;;AAIAH,OAAA,CAAQI,MAAR,GAAiB,YAAY;AAAA,I,sCAAA;AAAA,I,sCAAA;AAAA,IAC3B,OAAO,aAAP,CAD2B;AAAA,CAA7B',
+          file: 'testInputFile.js',
+          sourcesContent: [ '' ],
+          sourceRoot: 'testSourceRoot'
+        };
+        initStream.write(libFile);
+        initStream.end();
+    });
+
+    it('creates sourcemaps only if requested', function(done) {
+      this.stream.on('data', function (file) {
+        assert(file.sourceMap === undefined);
+        done();
+      });
+
+      this.stream.write(libFile);
+      this.stream.end();
+    });
   });
 
   describe('istanbul() with custom instrumentor', function() {